Clinical Imaging 38 (2014) 236–240
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
A strategy to optimize CT use in children with mild blunt head trauma utilizing clinical risk stratification; Could we improve CT use in children with mild head injury? Ali Kocyigit a,⁎, Mustafa Serinken b, Zumrut Ceven a, Atakan Yılmaz c, Furkan Kaya a, Celile Hatipoglu d, Serpil Yaylacı e, Nevzat Karabulut a a b c d e
Pamukkale University Faculty of Medicine, Department of Radiology, Denizli, Turkey Pamukkale University Faculty of Medicine, Department of Emergency Medicine, Denizli, Turkey Tekirdağ State Hospital, Department of Emergency Medicine, Tekirdağ, Turkey Pamukkale University Faculty of Medicine, Department of Public Health, Denizli, Turkey Acibadem University School of Medicine, Department of Emergency Medicine, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 7 September 2013 Received in revised form 25 November 2013 Accepted 12 December 2013 Keywords: Computed tomography Head trauma Pediatric Radiation dosage
a b s t r a c t Aim: The purpose of our study was to investigate the impact of clinical risk classification on optimization of the rationale of CT scanning in children with mild blunt head trauma. Exposed effective radiation dose values of CT scanning were also evaluated. Methods: Children with isolated pediatric mild head trauma admitted in a single center over a 5-year period (n=3102, N 2 years and b 16 years of age) were retrospectively reviewed. The study group comprised 806 patients with a mean age of 7.4±2.1 years (range, 2–15 years). The patients were categorized into low and high risk groups with regard to presence of predefined signs and symptoms. Effective radiation dose values were calculated. Results: Incidences of the pathologic CT findings related to trauma were significantly different between low (n=10) 1.9% and high (n=90) 29.8% risk groups. Certain predefined signs and symptoms (e.g., vomiting, suspected skull fracture and loss of consciousness) were related significantly with pathologic CT findings attributed to trauma. Estimated mean effective dose values were 3.91±0.38mSv for 2-6 year old (n=557), and 3.33±0.12mSv for 7-16 year old patients (n=349). Conclusion: The pediatric victims of mild head trauma patients within high risk group and those with vomiting, suspected skull fracture and loss of consciousness should undergo head CT scanning. The manufacturer settings on the CT scanners for children should be revised to alleviate untoward radiation exposure. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Traumatic head injury in pediatric population is one of the most common causes of admissions into the emergency departments (ED). Computed tomography (CT) is the most commonly employed tool to demonstrate suspected traumatic brain injury (TBI) in children particularly with moderate (GCS between 9 - 12) or severe (GCS between 3 - 8) head trauma. However, the indications of CT scanning for mild (GCS between 13 - 15) blunt head injury (MBHI) are still controversial and several guidelines are used by trauma centers and EDs [1,2]. These guidelines based upon some signs and symptoms related to the head ⁎ Corresponding author. Pamukkale University Hospital, Department of Radiology, Denizli, Turkey. E-mail addresses: [email protected] (A. Kocyigit), [email protected] (M. Serinken), [email protected] (Z. Ceven), [email protected] (A. Yılmaz), [email protected] (F. Kaya), [email protected] (C. Hatipoglu), [email protected] (S. Yaylacı), [email protected] (N. Karabulut). 0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2013.12.004
trauma as loss of consciousness (LOC), amnesia, vomiting, hyporeactivity, suspected skull fracture (rhinorrhea, otorrhea), severe or increasingly severe headache, asymmetric pupils, focal neurological findings, posttraumatic seizures which are used for the indication of CT examination. The clinical course of the majority of the mild head traumas goes uneventful and approximately 95% of the CT interpretations are normal [2]. Only 0.6% of the patients who underwent CT examination are admitted into hospital [2]. Therefore, the main questions regarding clinical guidelines for MBHI today probably involve the optimum use of CT, home care and in-hospital observation. Because of the high rates of normal CT examinations in the MBHI and pediatric population’s sensitivity to radiation exposure is, utilization of CT in the setting of MBHI should be optimized and the principle of As Low As Reasonably Achievable (ALARA) should be employed in the management of the victims of MBHI [3]. The primary goal of the present study is to determine if clinical classification of children with MBHI into high and low risk groups can predict the rate of abnormal CT examinations. The secondary goal was
A. Kocyigit et al. / Clinical Imaging 38 (2014) 236–240
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to define the significant risk factors for TBI in pediatric patients with MBHI who underwent CT scanning. 2. Materials and methods A retrospective review of pediatric victims of isolated mild blunt head injury (MBHI) (N2 years and b 16 years) admitted to ED of a tertiary care center between January 2007 and December 2011 were analyzed. Ethical approval was waived due to retrospective nature of the study. The exclusion criteria for the study were as follows: 1. Patients with multiple trauma (trauma to at least one of the other systems in addition to head injury). 2. Patients with penetrating head trauma. 3. Patients with a Glasgow Coma Scale (GCS) below 15. 4. Patients younger than two and older than 16 years of age. 5. Patients without CT scanning. 6. Patients with lack of data in the hospital information system. The data were collected from the hospital information system (HIS) and radiology information system. The demographic characteristics of patients, including age and gender, mechanism and etiology of the trauma, findings on physical examination, symptoms (headache, seizure, vomiting, etc.), GCS, interpretation of initial CT scanning and exposed radiation doses were documented. Patients with MBHI were categorized into low risk and high risk groups according to presence or absence of history of LOC, amnesia, vomiting, hyporeactivity, suspected skull fracture, severe or increasingly severe headache, asymmetric pupils, focal neurological findings, post-traumatic seizures, and a history of coagulopathy or continuing anticoagulant treatment. The patients with no signs or symptoms were assigned to the low risk group and those with any of the mentioned signs and symptoms were included in high risk group.
Fig. 1. The image shows automatic measurement values of CTDIvol and DLP.
with k factors calculated for each group (0.0040 and 0.0032, respectively) [4]. 2.3. Statistical analysis Statistical analysis was performed using the Statistical Package for Social Sciences for Windows, version 17. Descriptive statistics were calculated using mean±SD, frequency and percentage. The Chisquare tests (Pearson's chi-squared test, Yates' correction for continuity) or Fisher's exact test were used to compare proportions in different groups. A p-value of less than 0.05 was considered statistically significant result. 3. Results Overall, a total of 3102 pediatric trauma patients whom admitted to the ED in 5 year period were investigated. Of these 446 patients with multiple trauma, 1711 patients without CT scanning, 78 patients with a GCSb15, 54 patients with penetrating head injury and 7
2.1. Computed tomography scanning and assessment Axial head CT examinations were acquired using a 16-detector CT (Brilliance 16, Philips Medical Systems, Best, The Netherland) in supine position with a slightly extended head. The scanning line was parallel to the orbitomeatal line to prevent lens from direct irradiation. The average scanogram length was 225mm (200-250mm), and the scan area extended from the foramen magnum to the vertex. The tube voltage was 120kV, and tube current was 30mA for scanogram. Axial scanning parameters were as follows; tube voltage, 120kV; collimation, 16x0,75mm; matrix 512x512; rotation time 0.75 second; table speed, 9mm/second; pitch, 0.56 and slice thickness, 3mm. The effective tube current was in the range of 200-400 mAs and field of view (FOV) was in the range of 235-250mm adjusted according to the age, weight and size of the patients. No contrast material was administered. The CT images were then transferred to the PACS (Picture Archiving and Communication System). All the archived CT scans in the PACS were retrieved and retrospectively reviewed by a pediatric radiologist with 4 year experience. Subarachnoid, subdural and epidural hemorrhage, brain contusion and skull fractures were recorded as abnormal findings. The rest of the CT findings were recorded as normal (haematoma of the scalp was accepted as normal). 2.2. Radiation dose CTDIvol and DLP values calculated automatically by the CT system were archived as an image in PACS for each CT examination (Fig. 1). Patients were subdivided into two groups according to age as defined by American Association of Physicists in Medicine. For each patient, the effective radiation dose values were calculated according to age groups (19 months-6 years, and 7-16 years) by multiplying the DLP
Fig. 2. Patient flow chart.
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Table 1 The demographic and clinical characteristics of the patients
Gender Male Female Mechanism of injury Falls Motor vehicle accidents Sport injury Bicycle accidents Others Signs and symptoms Lacerated and contused wound Hyporeactivity (sleepiness) Vomiting Suspected skull fracture Loss of consciousness Amnesia Headache Asymmetric pupils Focal neurological deficit Seizure Coagulopathy CT evaluation Normal Abnormal Mode of disposition Discharge Admission
Table 3 The relationship between signs and symptoms and pathologic CT findings
n
%
Sign and symptoms (n)
Pathologic CT Number
Pathologic CT Percentage
p value
587 219
72.8 27.2
490 165 84 47 20
60.8 20.5 10.4 5.8 2.5
Lacerated and contused wound (88) Hyporeactivity (sleepiness) (31) Vomiting (206) Suspected skull fracture (42) Loss of consciousness (18) Amnesia (112) Headache (195)
5 6 81 27 11 30 26
5.6 19.3 39.3 64.2 61.1 26.8 13.3
0.082 0.250 b0.001 0.005 b0.001 0.059 0.481
88 31 206 42 18 112 195 2 2 1 0
10.9 3.8 25.5 5.3 2.2 13.9 24.2 0.2 0.2 0.1 0
710 96
88.1 11.9
737 69
91.4 8.6
patients with inadequate data for the study were excluded from the study. The remaining 806 patients with isolated minor head trauma constituted the study group (Fig. 2). The mean age of the study group was 7.4±2.1 years (range, 2 –15 years). Falling was the most frequent trauma mechanism (n=490, 60.8%), followed by by motor vehicle accidents (n=165, 20.5%). The demographic and clinical data of the patients are summarized in Table 1. Scalp haematoma, considered as an insignificant finding, was the most frequent CT finding (n=82, 10.1%) followed by skull fracture (n=69, 8.5%). Abnormal CT findings were encountered only in 96 (11.9%) patients. The comparison and distribution of these CT findings between low and high risk groups are demonstrated in Table 2. The rates of pathologic CT finding were significantly different between high risk group (n=90) 29.8% and low risk group (n=10) 1.9% (pb0,001). Vomiting, suspected skull fracture and LOC were the signs and symptoms which were related significantly with the pathologic CT findings (pb0.001, p=0.005, pb0001, respectively) (Table 3). Estimated mean effective dose values were 3.91mSv (2.3-4.48mSv) in 2-6 year-olds (n=557, 62.5%), and 3.33mSv (2.48-3.59mSv) in 7-16 year old patients (n=349, 38.5%), (Table 4).
Table 2 Distribution of CT findings between low and high risk groups⁎ CT findings (n)
Low risk group (n=504)
High risk group (n=302)
n
%
n
%
Scalp haematoma (82) Skull fracture (69) Brain contusion (14) Subdural hemorrhage (8) Epidural hemorrhage (5)
8 6 2 2 0
9.8 8.7 14.3 25.0 0
74 63 12 6 5
90.2 91,3 85,7 75,0 100.0
Subarachnoid hemorrhage (4)
0
0
4
100.0
⁎ Some patients had more than 1 intracranial injury.
p value
b0.001 b0.001 b0.001 0.058 Could not be evaluated Could not be evaluated
4. Discussion The present study indicates that the pathologic CT findings of skull fracture, brain contusion, subdural, epidural and subarachnoid haemorrhage were significantly higher in high risk patient group. The signs and symptoms of vomiting, suspected skull fracture and LOC also showed significant relationship with pathologic CT findings. The CT scan rate was 35% for overall study group with a pathologic finding rate of 11.9%. The exposed effective radiation doses were higher than the reported values in the literature [5]. There is a wide consensus for CT exam indications in moderate and severe pediatric head trauma patients in the literature [6]. On the contrary, the indications for CT scan in pediatric MBHI population is controversial and various guidelines were published [2]. All these guidelines are based on the signs and symptoms which may indicate a pathologic finding at CT examination. Fundaro et al reported that the CT scan rate was 58% among pediatric MBHI patients in their study [7]. In the present study, the CT scan rate (35%) in MBHI patients was smaller than that of Fundaro et al [7] and similar to that of Larson et al [8]. In the study by Fundaro et al [7], high rate of CT scanning was attributed to the guideline they used in their ED. In addition, they stated that if they followed different guidelines, they could avoid to perform 11% of the CT scanning rate. Various CT scanning rates in patients with mild head trauma could be related to different indication parameters of the ED. Furthermore these parameters are influenced not only from the guidelines or physician dependent assessment but also from the medicolegal issues. There are also some other reports highlighting this issue [9,10]. In our ED, no particular guideline is used for the pediatric MBHI management. Head CT is requested when any of the following is present: abnormal neurological findings on examination, GCS score less than 15, persistent severe headache, vomiting, posttraumatic amnesia, a history of LOC and findings suggestive of skull fracture. Moreover parents request for head CT examination was thevast majority of indications for head CT examination with a rate of 60 % [11]. Nevertheless CT scanning rates in the present study are similar to the other EDs reported in the literature [8]. Despite the formulation of clinical decision rules, less than 10% of CT scans in children with MBHI show TBI [12]. The accuracy and predictive value of these rules which could identify children at very low risk of TBI should be revised. In this study, we subdivided the patients with MBHI into low and high risk groups. There was a significant difference in the frequency of pathologic CT findings Table 4 CTDI, DLP and effective dose values according to age groups
2- 6 year (n=557) 7 - 15 year (n=349)
k factor
CTDIvol (mGy)
DLP (mGy.cm)
ED (mSv)
0.0040 0.0032
61.32±2.81 60.12±1.19
1002,25±96.1 1034,78±37.59
3.91±0.38 3.33±0.12
CTDIvol: Computed Tomography Dose Index, DLP: Dose Length Product, ED: Effective Dose. mGy: milliGray, mSv: milliSievert.
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between the low (1.9%) and high (29.8%) risk group. Servadei et al. subdivided the adult patients with MBHI into low-, medium- and high-risk groups [13]. They stated that low-risk MBHI patients were those with a GCS of 15 and without a history of loss of consciousness, amnesia, vomiting, or diffuse headache and the risk of TBI requiring surgery was less than 0.1 %. They suggested that these patients can be sent home with written recommendations. Medium risk mild injury patients have a GCS of 15 and one or more of the following symptoms: loss of consciousness, amnesia, vomiting, or diffuse headache. The risk of TBI requiring surgery was in the range of 1-3 % and a CT scan should be obtained for such patients. High-risk mild head injury patients were those with an admission GCS of 14 or 15, with a skull fracture and/or neurological deficits. The risk of TBI requiring surgery was in the range of 6-10 % and a CT scan must be obtained. Finally they recommended CT scanning for medium and high risk patients. Turedi et al [14] stated that the abnormal CT scanning rates for the pediatric patients according to low and high risk group were 10% and 40% respectively. If one of the following finding; a history of LOC, amnesia, vomiting, suspected skull fracture, presence of multiple trauma, severe or increasingly severe headache, asymmetric pupils, focal neurological findings, post-traumatic seizures, a history of coagulopathy or continuing anticoagulant treatment, and a GCS score of 14 or 15, was present, the patient would be defined in the high risk group. In our study, the rate of abnormal CT scans for the low and high risk group was smaller than that of Turedi et al. This can be related to the small number of pediatric patients (n=60) in their study, and inclusion of patients with multiple trauma and GCS of 14. In the light of these results, the low and high risk classification can be used in pediatric MBHI patients in decision making process to discharge home without CT scanning and to perform CT scanning respectively. Inspite of using low and high risk classification, the percent of positive CT examination couldn't be decreased to zero. Hence the clinical followup of these patients should be observed even by the parents to avoid missing patients with TBI. Several studies [6,15] reported that local pathological physical examination findings of the head (head swelling, suspected skull fracture or lacerated and contused wound) represent statistically significant predictors of abnormal CT. This study demonstrated that suspected skull fracture was a significant factor for abnormal CT. However the scalp haematoma, and lacerated or contused wound of the head were not significant predictors for abnormal CT. Furthermore the present study revealed that LOC and vomiting were significant risk factors for abnormal CT similar to the study by Fundoro et al [7]. On the other hand, some authors stated that a prolonged LOC (N5 min) was associated with a high risk of intracranial lesion [16,17]. Fundoro et al [7] reported that 10.6% of children presented with LOC of b1min underwent neurosurgical treatment. In line with this, we found that LOC may be an indicator of CT examination for patients with MBHI. The LOC in young children is often difficult to define and this can be the reason for conflicting results in the literature [15]. In the pediatric population the value of vomiting as an indicator of abnormal CT is less clear. Some studies revealed vomiting as an insignificant factor for intracranial injury [2]. Turedi et al reported vomiting as a significant factor for abnormal CT [14]. In this study, vomiting was found to be a significant factor for abnormal CT scanning and it can be used as an indication for CT scanning in pediatric MBHI patients. Increased awareness of the potential long-term hazards of ionizing radiation in children [18] has led physicians to justify CT use without compromising patient care [19]. McCollough et al [5] reported the average effective radiation dose of head CT scanning in pediatric patients as 1-2mSv. In the present study, the effective radiation dose was approximately twice higher than the former reported values. The investigation of the reasons of this high effective radiation dose values revealed that the head CT scanning parameters (mAs: 200-400, kVp: 120) set by the manufacturer for pediatric patients were much higher
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than the accepted values defined in literature (5) (mAs: 50, kVp: 120). Furthermore the radiology technicians working in the ED were novice and inexpert staff, and they probably preferred to use manufacturer’s preset parameters rather than adjusting scanning parameters according to patient age, sex and body weight [20]. After the study, we reset the pediatric CT scanning parameters of the CT system, and refreshed the knowledge of radiology technicians in the ED to decrease effective radiation dose in our department. Hence, we suggest to recheck the preset CT scan parameters of the CT systems by the manufacturers, and pay attention to the education of the radiology technicians about the patient specific CT scanning parameters in the radiology departments. There was some major limitations of this retrospective study. Because of the retrospective nature of the study missing data and selection bias were unavoidable limitations. We could not find any record about the severity of the headache for the patients with MBHI. Furthermore the time of amnesia and LOC and the number of vomiting were also not taken into assessment because of the lack of adequate record. Another major limitation was; although there was no negative follow-up data in HIS for the non CT examination MBHI group, we did not know if these patients had gone to another medical center due to complications of MBHI. Also we investigated initial CT findings just after the ED attendance of MBHI patients and we did not know the time interval between the head trauma and ED attendance. On the other hand, the patients below GCS 15 were excluded from the study and this situation limited the number of patients. However, the patients with GCS 13–14 have a significantly increased overall risk compared to patients with GCS 15 and CT scanning is already indicated for GCS 13-14 patients [21]. Therefore the management strategy of GCS 15 patients without CT scanning is the main issue. Furthermore the vast majority of patients with mild head injury is GCS 15 patients [21]. In a recent prediction rule developed by Atabaki et al. age below 2 years is also considered a risk factor per se because many clinical symptoms can not be assessed in this very young age group [22]. Thus, children younger than 2 years of age were excluded from the study. In conclusion, overuse of CT in mild head trauma patients leads to redundant ionizing radiation exposure. Low and high risk classification can be used for ED discharge of low risk patients without CT scanning. Patients with GCS of 15, those with vomiting, suspected skull fracture and LOC should undergo head CT scanning. The manufacturer settings on the CT scanner should be revised. Finally, there is a need for further prospective studies with larger series to evaluate all high-risk factors in relation to indications for delayed CT scan in patients with mild head injuries. References [1] Andruszkow H, Urner J, Deniz E, Probst C, Grün O, Lohse R, et al. Subjective impact of traumatic brain injury on long-term outcome at a minimum of 10 years after trauma- first results of a survey on 368 patients from a single academic trauma center in Germany. Patient Saf Surg 2013;7:32. [2] Schachar JL, Zampolin RL, Miller TS, Farinhas JM, Freeman K, Taragin BH. External validation of the New Orleans Criteria (NOC), the Canadian CT Head Rule (CCHR) and the National Emergency X-Radiography Utilization Study II (NEXUS II) for CT scanning in pediatric patients with minor head injury in a non-trauma center. Pediatr Radiol 2011;41:971–9. [3] Slovis TL. Children, computed tomography radiation dose, and the As Low As Reasonably Achievable (ALARA) concept. Pediatrics 2003;112:971–2. [4] McCollough C, Branham T, Herlihy V, Bhargavan M, Robbins L, Bush K, et al. Diagnostic reference levels from the ACR CT Accreditation Program. J Am Coll Radiol 2011;8:795–803. [5] McCollough CH, Christner JA, Kofler JM. How Effective Is Effective Dose as a Predictor of Radiation Risk? Am J Roentgenol 2010;194:890–6. [6] Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K. Derivation of the children’s head injury algorithm for the prediction of important clinical events decision rule for head injury in children. Arch Dis Child 2006;91:885–91. [7] Fundaro C, Caldarelli M, Monaco S, Cota F, Giorgio V, Filoni S, et al. Brain CT scan for pediatric minor accidental head injury. An Italian experience and review of literature. Childs Nerv Syst 2012;28:1063–8. [8] Larson DB, Johnson LW, Schnell BM, Salisbury SR, Forman HP. Rising use of CT in child visits to the emergency department in the United States, 1995–2008. Radiology 2011;259:793–801.
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[9] Ryu WH, Feinstein A, Colantonio A, Streiner DL, Dawson D. Regional Variability in the Use of CT for Patients with Suspected Mild Traumatic Brain Injury. Can J Neurol Sci 2009;36:42–6. [10] Wong AC, Kowalenko T, Roahen-Harrison S, Smith B, Maio RF, Stanley RM. A Survey of Emergency Physicians’ Fear of Malpractice and Its Association With the Decision to Order Computed Tomography Scans for Children With Minor Head Trauma. J Pediatr Emerg Care 2011;27:182–5. [11] Serinken M, Kocyigit A, Karcioglu O, Sengül C, Hatipoglu C, Elicabuk H. Parental anxiety and affecting factors in acute paediatric blunt head injury. Emerg Med J May 18 2013. http://dx.doi.org/10.1136/emermed-2013-202492. [12] Kuppermann N, Holmes JF, Dayan PS, Hoyle JD, Atabaki SM, Holubkov R, et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet 2009;374:1160–70. [13] Servadei F, Teasdale G, Merry G. Neurotraumatology Committee of the World Federation of Neurosurgical Societies. Defining acute mild head injury in adults: a proposal based on prognostic factors, diagnosis and management. J Neurotrauma 2001;18:657–64. [14] Türedi S, Hasanbasoglu A, Gunduz A, Yandi M. Clinical decision instruments for CT scan in minor head trauma. J Emerg Med 2008;34:253–9.
[15] Homer CJ, Kleinman L. Technical report: minor head injury in children. Pediatrics 2003;104:1–7. [16] Klemetti S, Uhari M, Pokka T, Rantala H. Evaluation of decision rules for identifying serious consequences of traumatic head injuries in pediatric patient. Pediatr Emerg Care 2009;25:811–5. [17] Haydel MJ, Shembekar AD. Prediction of intracranial injury in children aged five years and older with loss of consciousness after minor head injury due to non trivial mechanisms. Ann Emerg Med 2003;42:507–14. [18] Smith-Bindman R. Is computed tomography safe? N Engl J Med 2010;363:1–4. [19] Brenner DJ, Hricak H. Radiation exposure from medical imaging: time to regulate? JAMA 2010;304:208–9. [20] Dougeni E, Faulkner K, Panayiotakis G. A review of patient dose and optimisation methods in adult and paediatric CT. Eur J Radiol 2012;81:665–83. [21] af Geijerstam JL, Britton M. Mild head injury mortality and complication rate: meta-analysis of findings in a systematic literature review. Acta Neurochir 2003;145:843–50. [22] Atabaki SM, Stiell IG, Bazarian JJ, Sadow KE, Vu TT, Camarca MA, et al. A clinical decision rule for cranial computed tomography in minor pediatric head trauma. Arch Pediatr Adolesc Med 2008;162:439.
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
A strategy to optimize CT use in children with mild blunt head trauma utilizing clinical risk stratification; Could we improve CT use in children with mild head injury? Ali Kocyigit a,⁎, Mustafa Serinken b, Zumrut Ceven a, Atakan Yılmaz c, Furkan Kaya a, Celile Hatipoglu d, Serpil Yaylacı e, Nevzat Karabulut a a b c d e
Pamukkale University Faculty of Medicine, Department of Radiology, Denizli, Turkey Pamukkale University Faculty of Medicine, Department of Emergency Medicine, Denizli, Turkey Tekirdağ State Hospital, Department of Emergency Medicine, Tekirdağ, Turkey Pamukkale University Faculty of Medicine, Department of Public Health, Denizli, Turkey Acibadem University School of Medicine, Department of Emergency Medicine, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 7 September 2013 Received in revised form 25 November 2013 Accepted 12 December 2013 Keywords: Computed tomography Head trauma Pediatric Radiation dosage
a b s t r a c t Aim: The purpose of our study was to investigate the impact of clinical risk classification on optimization of the rationale of CT scanning in children with mild blunt head trauma. Exposed effective radiation dose values of CT scanning were also evaluated. Methods: Children with isolated pediatric mild head trauma admitted in a single center over a 5-year period (n=3102, N 2 years and b 16 years of age) were retrospectively reviewed. The study group comprised 806 patients with a mean age of 7.4±2.1 years (range, 2–15 years). The patients were categorized into low and high risk groups with regard to presence of predefined signs and symptoms. Effective radiation dose values were calculated. Results: Incidences of the pathologic CT findings related to trauma were significantly different between low (n=10) 1.9% and high (n=90) 29.8% risk groups. Certain predefined signs and symptoms (e.g., vomiting, suspected skull fracture and loss of consciousness) were related significantly with pathologic CT findings attributed to trauma. Estimated mean effective dose values were 3.91±0.38mSv for 2-6 year old (n=557), and 3.33±0.12mSv for 7-16 year old patients (n=349). Conclusion: The pediatric victims of mild head trauma patients within high risk group and those with vomiting, suspected skull fracture and loss of consciousness should undergo head CT scanning. The manufacturer settings on the CT scanners for children should be revised to alleviate untoward radiation exposure. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Traumatic head injury in pediatric population is one of the most common causes of admissions into the emergency departments (ED). Computed tomography (CT) is the most commonly employed tool to demonstrate suspected traumatic brain injury (TBI) in children particularly with moderate (GCS between 9 - 12) or severe (GCS between 3 - 8) head trauma. However, the indications of CT scanning for mild (GCS between 13 - 15) blunt head injury (MBHI) are still controversial and several guidelines are used by trauma centers and EDs [1,2]. These guidelines based upon some signs and symptoms related to the head ⁎ Corresponding author. Pamukkale University Hospital, Department of Radiology, Denizli, Turkey. E-mail addresses: [email protected] (A. Kocyigit), [email protected] (M. Serinken), [email protected] (Z. Ceven), [email protected] (A. Yılmaz), [email protected] (F. Kaya), [email protected] (C. Hatipoglu), [email protected] (S. Yaylacı), [email protected] (N. Karabulut). 0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2013.12.004
trauma as loss of consciousness (LOC), amnesia, vomiting, hyporeactivity, suspected skull fracture (rhinorrhea, otorrhea), severe or increasingly severe headache, asymmetric pupils, focal neurological findings, posttraumatic seizures which are used for the indication of CT examination. The clinical course of the majority of the mild head traumas goes uneventful and approximately 95% of the CT interpretations are normal [2]. Only 0.6% of the patients who underwent CT examination are admitted into hospital [2]. Therefore, the main questions regarding clinical guidelines for MBHI today probably involve the optimum use of CT, home care and in-hospital observation. Because of the high rates of normal CT examinations in the MBHI and pediatric population’s sensitivity to radiation exposure is, utilization of CT in the setting of MBHI should be optimized and the principle of As Low As Reasonably Achievable (ALARA) should be employed in the management of the victims of MBHI [3]. The primary goal of the present study is to determine if clinical classification of children with MBHI into high and low risk groups can predict the rate of abnormal CT examinations. The secondary goal was
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to define the significant risk factors for TBI in pediatric patients with MBHI who underwent CT scanning. 2. Materials and methods A retrospective review of pediatric victims of isolated mild blunt head injury (MBHI) (N2 years and b 16 years) admitted to ED of a tertiary care center between January 2007 and December 2011 were analyzed. Ethical approval was waived due to retrospective nature of the study. The exclusion criteria for the study were as follows: 1. Patients with multiple trauma (trauma to at least one of the other systems in addition to head injury). 2. Patients with penetrating head trauma. 3. Patients with a Glasgow Coma Scale (GCS) below 15. 4. Patients younger than two and older than 16 years of age. 5. Patients without CT scanning. 6. Patients with lack of data in the hospital information system. The data were collected from the hospital information system (HIS) and radiology information system. The demographic characteristics of patients, including age and gender, mechanism and etiology of the trauma, findings on physical examination, symptoms (headache, seizure, vomiting, etc.), GCS, interpretation of initial CT scanning and exposed radiation doses were documented. Patients with MBHI were categorized into low risk and high risk groups according to presence or absence of history of LOC, amnesia, vomiting, hyporeactivity, suspected skull fracture, severe or increasingly severe headache, asymmetric pupils, focal neurological findings, post-traumatic seizures, and a history of coagulopathy or continuing anticoagulant treatment. The patients with no signs or symptoms were assigned to the low risk group and those with any of the mentioned signs and symptoms were included in high risk group.
Fig. 1. The image shows automatic measurement values of CTDIvol and DLP.
with k factors calculated for each group (0.0040 and 0.0032, respectively) [4]. 2.3. Statistical analysis Statistical analysis was performed using the Statistical Package for Social Sciences for Windows, version 17. Descriptive statistics were calculated using mean±SD, frequency and percentage. The Chisquare tests (Pearson's chi-squared test, Yates' correction for continuity) or Fisher's exact test were used to compare proportions in different groups. A p-value of less than 0.05 was considered statistically significant result. 3. Results Overall, a total of 3102 pediatric trauma patients whom admitted to the ED in 5 year period were investigated. Of these 446 patients with multiple trauma, 1711 patients without CT scanning, 78 patients with a GCSb15, 54 patients with penetrating head injury and 7
2.1. Computed tomography scanning and assessment Axial head CT examinations were acquired using a 16-detector CT (Brilliance 16, Philips Medical Systems, Best, The Netherland) in supine position with a slightly extended head. The scanning line was parallel to the orbitomeatal line to prevent lens from direct irradiation. The average scanogram length was 225mm (200-250mm), and the scan area extended from the foramen magnum to the vertex. The tube voltage was 120kV, and tube current was 30mA for scanogram. Axial scanning parameters were as follows; tube voltage, 120kV; collimation, 16x0,75mm; matrix 512x512; rotation time 0.75 second; table speed, 9mm/second; pitch, 0.56 and slice thickness, 3mm. The effective tube current was in the range of 200-400 mAs and field of view (FOV) was in the range of 235-250mm adjusted according to the age, weight and size of the patients. No contrast material was administered. The CT images were then transferred to the PACS (Picture Archiving and Communication System). All the archived CT scans in the PACS were retrieved and retrospectively reviewed by a pediatric radiologist with 4 year experience. Subarachnoid, subdural and epidural hemorrhage, brain contusion and skull fractures were recorded as abnormal findings. The rest of the CT findings were recorded as normal (haematoma of the scalp was accepted as normal). 2.2. Radiation dose CTDIvol and DLP values calculated automatically by the CT system were archived as an image in PACS for each CT examination (Fig. 1). Patients were subdivided into two groups according to age as defined by American Association of Physicists in Medicine. For each patient, the effective radiation dose values were calculated according to age groups (19 months-6 years, and 7-16 years) by multiplying the DLP
Fig. 2. Patient flow chart.
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Table 1 The demographic and clinical characteristics of the patients
Gender Male Female Mechanism of injury Falls Motor vehicle accidents Sport injury Bicycle accidents Others Signs and symptoms Lacerated and contused wound Hyporeactivity (sleepiness) Vomiting Suspected skull fracture Loss of consciousness Amnesia Headache Asymmetric pupils Focal neurological deficit Seizure Coagulopathy CT evaluation Normal Abnormal Mode of disposition Discharge Admission
Table 3 The relationship between signs and symptoms and pathologic CT findings
n
%
Sign and symptoms (n)
Pathologic CT Number
Pathologic CT Percentage
p value
587 219
72.8 27.2
490 165 84 47 20
60.8 20.5 10.4 5.8 2.5
Lacerated and contused wound (88) Hyporeactivity (sleepiness) (31) Vomiting (206) Suspected skull fracture (42) Loss of consciousness (18) Amnesia (112) Headache (195)
5 6 81 27 11 30 26
5.6 19.3 39.3 64.2 61.1 26.8 13.3
0.082 0.250 b0.001 0.005 b0.001 0.059 0.481
88 31 206 42 18 112 195 2 2 1 0
10.9 3.8 25.5 5.3 2.2 13.9 24.2 0.2 0.2 0.1 0
710 96
88.1 11.9
737 69
91.4 8.6
patients with inadequate data for the study were excluded from the study. The remaining 806 patients with isolated minor head trauma constituted the study group (Fig. 2). The mean age of the study group was 7.4±2.1 years (range, 2 –15 years). Falling was the most frequent trauma mechanism (n=490, 60.8%), followed by by motor vehicle accidents (n=165, 20.5%). The demographic and clinical data of the patients are summarized in Table 1. Scalp haematoma, considered as an insignificant finding, was the most frequent CT finding (n=82, 10.1%) followed by skull fracture (n=69, 8.5%). Abnormal CT findings were encountered only in 96 (11.9%) patients. The comparison and distribution of these CT findings between low and high risk groups are demonstrated in Table 2. The rates of pathologic CT finding were significantly different between high risk group (n=90) 29.8% and low risk group (n=10) 1.9% (pb0,001). Vomiting, suspected skull fracture and LOC were the signs and symptoms which were related significantly with the pathologic CT findings (pb0.001, p=0.005, pb0001, respectively) (Table 3). Estimated mean effective dose values were 3.91mSv (2.3-4.48mSv) in 2-6 year-olds (n=557, 62.5%), and 3.33mSv (2.48-3.59mSv) in 7-16 year old patients (n=349, 38.5%), (Table 4).
Table 2 Distribution of CT findings between low and high risk groups⁎ CT findings (n)
Low risk group (n=504)
High risk group (n=302)
n
%
n
%
Scalp haematoma (82) Skull fracture (69) Brain contusion (14) Subdural hemorrhage (8) Epidural hemorrhage (5)
8 6 2 2 0
9.8 8.7 14.3 25.0 0
74 63 12 6 5
90.2 91,3 85,7 75,0 100.0
Subarachnoid hemorrhage (4)
0
0
4
100.0
⁎ Some patients had more than 1 intracranial injury.
p value
b0.001 b0.001 b0.001 0.058 Could not be evaluated Could not be evaluated
4. Discussion The present study indicates that the pathologic CT findings of skull fracture, brain contusion, subdural, epidural and subarachnoid haemorrhage were significantly higher in high risk patient group. The signs and symptoms of vomiting, suspected skull fracture and LOC also showed significant relationship with pathologic CT findings. The CT scan rate was 35% for overall study group with a pathologic finding rate of 11.9%. The exposed effective radiation doses were higher than the reported values in the literature [5]. There is a wide consensus for CT exam indications in moderate and severe pediatric head trauma patients in the literature [6]. On the contrary, the indications for CT scan in pediatric MBHI population is controversial and various guidelines were published [2]. All these guidelines are based on the signs and symptoms which may indicate a pathologic finding at CT examination. Fundaro et al reported that the CT scan rate was 58% among pediatric MBHI patients in their study [7]. In the present study, the CT scan rate (35%) in MBHI patients was smaller than that of Fundaro et al [7] and similar to that of Larson et al [8]. In the study by Fundaro et al [7], high rate of CT scanning was attributed to the guideline they used in their ED. In addition, they stated that if they followed different guidelines, they could avoid to perform 11% of the CT scanning rate. Various CT scanning rates in patients with mild head trauma could be related to different indication parameters of the ED. Furthermore these parameters are influenced not only from the guidelines or physician dependent assessment but also from the medicolegal issues. There are also some other reports highlighting this issue [9,10]. In our ED, no particular guideline is used for the pediatric MBHI management. Head CT is requested when any of the following is present: abnormal neurological findings on examination, GCS score less than 15, persistent severe headache, vomiting, posttraumatic amnesia, a history of LOC and findings suggestive of skull fracture. Moreover parents request for head CT examination was thevast majority of indications for head CT examination with a rate of 60 % [11]. Nevertheless CT scanning rates in the present study are similar to the other EDs reported in the literature [8]. Despite the formulation of clinical decision rules, less than 10% of CT scans in children with MBHI show TBI [12]. The accuracy and predictive value of these rules which could identify children at very low risk of TBI should be revised. In this study, we subdivided the patients with MBHI into low and high risk groups. There was a significant difference in the frequency of pathologic CT findings Table 4 CTDI, DLP and effective dose values according to age groups
2- 6 year (n=557) 7 - 15 year (n=349)
k factor
CTDIvol (mGy)
DLP (mGy.cm)
ED (mSv)
0.0040 0.0032
61.32±2.81 60.12±1.19
1002,25±96.1 1034,78±37.59
3.91±0.38 3.33±0.12
CTDIvol: Computed Tomography Dose Index, DLP: Dose Length Product, ED: Effective Dose. mGy: milliGray, mSv: milliSievert.
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between the low (1.9%) and high (29.8%) risk group. Servadei et al. subdivided the adult patients with MBHI into low-, medium- and high-risk groups [13]. They stated that low-risk MBHI patients were those with a GCS of 15 and without a history of loss of consciousness, amnesia, vomiting, or diffuse headache and the risk of TBI requiring surgery was less than 0.1 %. They suggested that these patients can be sent home with written recommendations. Medium risk mild injury patients have a GCS of 15 and one or more of the following symptoms: loss of consciousness, amnesia, vomiting, or diffuse headache. The risk of TBI requiring surgery was in the range of 1-3 % and a CT scan should be obtained for such patients. High-risk mild head injury patients were those with an admission GCS of 14 or 15, with a skull fracture and/or neurological deficits. The risk of TBI requiring surgery was in the range of 6-10 % and a CT scan must be obtained. Finally they recommended CT scanning for medium and high risk patients. Turedi et al [14] stated that the abnormal CT scanning rates for the pediatric patients according to low and high risk group were 10% and 40% respectively. If one of the following finding; a history of LOC, amnesia, vomiting, suspected skull fracture, presence of multiple trauma, severe or increasingly severe headache, asymmetric pupils, focal neurological findings, post-traumatic seizures, a history of coagulopathy or continuing anticoagulant treatment, and a GCS score of 14 or 15, was present, the patient would be defined in the high risk group. In our study, the rate of abnormal CT scans for the low and high risk group was smaller than that of Turedi et al. This can be related to the small number of pediatric patients (n=60) in their study, and inclusion of patients with multiple trauma and GCS of 14. In the light of these results, the low and high risk classification can be used in pediatric MBHI patients in decision making process to discharge home without CT scanning and to perform CT scanning respectively. Inspite of using low and high risk classification, the percent of positive CT examination couldn't be decreased to zero. Hence the clinical followup of these patients should be observed even by the parents to avoid missing patients with TBI. Several studies [6,15] reported that local pathological physical examination findings of the head (head swelling, suspected skull fracture or lacerated and contused wound) represent statistically significant predictors of abnormal CT. This study demonstrated that suspected skull fracture was a significant factor for abnormal CT. However the scalp haematoma, and lacerated or contused wound of the head were not significant predictors for abnormal CT. Furthermore the present study revealed that LOC and vomiting were significant risk factors for abnormal CT similar to the study by Fundoro et al [7]. On the other hand, some authors stated that a prolonged LOC (N5 min) was associated with a high risk of intracranial lesion [16,17]. Fundoro et al [7] reported that 10.6% of children presented with LOC of b1min underwent neurosurgical treatment. In line with this, we found that LOC may be an indicator of CT examination for patients with MBHI. The LOC in young children is often difficult to define and this can be the reason for conflicting results in the literature [15]. In the pediatric population the value of vomiting as an indicator of abnormal CT is less clear. Some studies revealed vomiting as an insignificant factor for intracranial injury [2]. Turedi et al reported vomiting as a significant factor for abnormal CT [14]. In this study, vomiting was found to be a significant factor for abnormal CT scanning and it can be used as an indication for CT scanning in pediatric MBHI patients. Increased awareness of the potential long-term hazards of ionizing radiation in children [18] has led physicians to justify CT use without compromising patient care [19]. McCollough et al [5] reported the average effective radiation dose of head CT scanning in pediatric patients as 1-2mSv. In the present study, the effective radiation dose was approximately twice higher than the former reported values. The investigation of the reasons of this high effective radiation dose values revealed that the head CT scanning parameters (mAs: 200-400, kVp: 120) set by the manufacturer for pediatric patients were much higher
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than the accepted values defined in literature (5) (mAs: 50, kVp: 120). Furthermore the radiology technicians working in the ED were novice and inexpert staff, and they probably preferred to use manufacturer’s preset parameters rather than adjusting scanning parameters according to patient age, sex and body weight [20]. After the study, we reset the pediatric CT scanning parameters of the CT system, and refreshed the knowledge of radiology technicians in the ED to decrease effective radiation dose in our department. Hence, we suggest to recheck the preset CT scan parameters of the CT systems by the manufacturers, and pay attention to the education of the radiology technicians about the patient specific CT scanning parameters in the radiology departments. There was some major limitations of this retrospective study. Because of the retrospective nature of the study missing data and selection bias were unavoidable limitations. We could not find any record about the severity of the headache for the patients with MBHI. Furthermore the time of amnesia and LOC and the number of vomiting were also not taken into assessment because of the lack of adequate record. Another major limitation was; although there was no negative follow-up data in HIS for the non CT examination MBHI group, we did not know if these patients had gone to another medical center due to complications of MBHI. Also we investigated initial CT findings just after the ED attendance of MBHI patients and we did not know the time interval between the head trauma and ED attendance. On the other hand, the patients below GCS 15 were excluded from the study and this situation limited the number of patients. However, the patients with GCS 13–14 have a significantly increased overall risk compared to patients with GCS 15 and CT scanning is already indicated for GCS 13-14 patients [21]. Therefore the management strategy of GCS 15 patients without CT scanning is the main issue. Furthermore the vast majority of patients with mild head injury is GCS 15 patients [21]. In a recent prediction rule developed by Atabaki et al. age below 2 years is also considered a risk factor per se because many clinical symptoms can not be assessed in this very young age group [22]. Thus, children younger than 2 years of age were excluded from the study. In conclusion, overuse of CT in mild head trauma patients leads to redundant ionizing radiation exposure. Low and high risk classification can be used for ED discharge of low risk patients without CT scanning. Patients with GCS of 15, those with vomiting, suspected skull fracture and LOC should undergo head CT scanning. The manufacturer settings on the CT scanner should be revised. Finally, there is a need for further prospective studies with larger series to evaluate all high-risk factors in relation to indications for delayed CT scan in patients with mild head injuries. References [1] Andruszkow H, Urner J, Deniz E, Probst C, Grün O, Lohse R, et al. Subjective impact of traumatic brain injury on long-term outcome at a minimum of 10 years after trauma- first results of a survey on 368 patients from a single academic trauma center in Germany. Patient Saf Surg 2013;7:32. [2] Schachar JL, Zampolin RL, Miller TS, Farinhas JM, Freeman K, Taragin BH. External validation of the New Orleans Criteria (NOC), the Canadian CT Head Rule (CCHR) and the National Emergency X-Radiography Utilization Study II (NEXUS II) for CT scanning in pediatric patients with minor head injury in a non-trauma center. Pediatr Radiol 2011;41:971–9. [3] Slovis TL. Children, computed tomography radiation dose, and the As Low As Reasonably Achievable (ALARA) concept. Pediatrics 2003;112:971–2. [4] McCollough C, Branham T, Herlihy V, Bhargavan M, Robbins L, Bush K, et al. Diagnostic reference levels from the ACR CT Accreditation Program. J Am Coll Radiol 2011;8:795–803. [5] McCollough CH, Christner JA, Kofler JM. How Effective Is Effective Dose as a Predictor of Radiation Risk? Am J Roentgenol 2010;194:890–6. [6] Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K. Derivation of the children’s head injury algorithm for the prediction of important clinical events decision rule for head injury in children. Arch Dis Child 2006;91:885–91. [7] Fundaro C, Caldarelli M, Monaco S, Cota F, Giorgio V, Filoni S, et al. Brain CT scan for pediatric minor accidental head injury. An Italian experience and review of literature. Childs Nerv Syst 2012;28:1063–8. [8] Larson DB, Johnson LW, Schnell BM, Salisbury SR, Forman HP. Rising use of CT in child visits to the emergency department in the United States, 1995–2008. Radiology 2011;259:793–801.
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