Stroke
MARCH-APRIL VOL. 7
1976 NO. 2
A Journal of Cerebral Circulation Comparison of Computerized Tomography and Radionuclide Imaging in "Stroke".99 MOKHTAR H . GADO, M.D., R. EDWARD C O L E M A N , M.D., ANTHONY L. MERLIS, M.D., PHILIP O. ALDERSON, M.D., AND KIL SOO LEE, M.D.
SUMMARY Forty patients were studied by computerized tomography and by radionuclide brain imaging. The final diagnosis was infarction in 29 patients, intracerebral hematoma in seven, acute SAH in one, and old cerebrovascular accidents in three. CT was far superior to RN in detecting intracerebral hematomas and distinguishing them from cerebral infarction. The results of CT and RN
tests were comparable regarding the percentage of abnormalities. However, the results in the same patients were not identical in 55% of the cases, indicating a complementary role for the two tests. There was no relationship between the frequency of abnormalities on CT and the time lapse after the onset of cerebral infarction. RN uptake was not seen in patients with old cerebrovascular accidents.
SINCE THE INTRODUCTION of computerized tomography (CT) as a noninvasive technique for brain imaging, several reports have discussed its usefulness in patients with stroke. The purpose of this communication is to compare CT and radionuclide brain scanning in patients with cerebrovascular disease.
patients. Three patients admitted for evaluation of late sequelae of a cerebrovascular accident that had occurred one year earlier are included in the last column of table 1. In this study there was a slight inadvertent selection of patients resulting in a slight artificial bias in the results. During the greater part of the period covered in this study there was a single CT unit in operation at our institute. As a result of the inevitable waiting list, some patients with a negative RN study were not studied by CT. It is quite possible, therefore, that a group of patients with negative isotope studies and positive CT was inadvertently omitted from the study. This will be discussed later. CT scans were performed with an EMI scanner, using the standard technique. The x-ray tube was operated at 120 KVP and 33 mA with 13 mm collimation of the beam. The scan was done at a plane of 20° above the orbitomeatal plane. The image consisted of an 80 X 80 matrix in the studies of the first 17 patients. The remaining 23 patients were studied by the 160 X 160 matrix. The RN brain scan was performed utilizing a scintillation camera and the intravenous injection of MmTc-pertechnetate (15 to 20 mCi in 1 to 4 cc of saline). A rapid sequence study was performed at the time of the injection, using a high sensitivity parallel hole collimator. Static brain imaging was performed approximately 30 minutes after injection using a high resolution parallel hole collimator. When necessary, delayed images (two to four hours) were obtained.
Methods There were 40 patients with a final diagnosis of cerebrovascular accident. Each patient was examined by CT and radionuclide (RN) brain imaging. There were 29 cases of recent infarction (28 in the cerebral hemisphere and one in the cerebellum), seven cases of intracerebral hemorrhage, and one with subarachnoid hemorrhage (SAH). The diagnosis of cerebral infarction was made on clinical grounds. The diagnosis of intracerebral hematoma was confirmed by surgery in three cases and by autopsy in two. There were two cases in this series in which the diagnosis of a hematoma was based on the CT scan. The interval between the onset of symptoms and the diagnostic imaging in this group of patients is shown in table 1. The time lapse between CT and RN brain imaging was less than one week in the same patient, with a mean of 1.8 days. As shown in table 1, CT was done in the first two days in 15 patients, between two and seven days after the onset in 13 patients, between seven and 21 days in six patients, and more than 21 days after the onset in six patients. RN studies were done in the first two days in 18 patients, between two and seven days after the episode in 13 patients, between seven and 21 days in four patients, and more than 21 days after the episode in five
Results Of the 29 patients with recent infarction, 16 patients (55%) showed abnormality on the CT scan and 20 (69%) showed abnormality on RN brain imaging (table 2). The abnormality on CT consisted of decreased density of the brain tissue (fig. 1). None of the patients had evidence of brain swelling on CT. Twenty of the patients showed increased up-
From the Neuroradiology Section and the Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway, St. Louis, Missouri 63110. Supported in part by Neuroradiology Training Grant NIH-5-T01-NS0522-08. Reprint requests to Dr. Gado, Associate Professor, Chief, Neuroradiology Section.
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TABLE 1 Time Interval Between Cerebrovascular Accident and Imaging Studies Days
CT RN
0-2
2-7
7-21
>21
Total
15 18
13 13
6 4
6 5
40 40
take on radionuclide imaging (fig. 2). Rapid sequence scintigraphy was done on 14 of these patients and showed decreased vascularity in three, a flip-flop phenomenon (fig. 3) in one, and normal results in ten. There was no increased uptake in eight patients with recent infarction. Rapid sequence scintigraphy was done on four of them and showed decreased vascularity in three, all of whom had a positive CT. There were three cases in which both the CT and radionuclide study were negative. Rapid sequence scintigraphy was done on one of these and it also was negative (table 3). Of the three patients evaluated one year after a cerebrovascular accident, none showed increased uptake on radionuclide images. Rapid sequence scintigraphy was done on two of them and showed a flip-flop phenomenon in both. CT was positive in all three cases. The results of RN and CT studies were analyzed in relation to the time interval between the scan and the onset of symptoms in the 29 patients with cerebral infarction (table 4). The studies were divided into four groups in which the time interval was 0 to 2 days, 2 to 7 days, 7 to 21 days, and greater than 21 days, respectively. Radionuclide imaging showed an increase in the percentage of detectable cases in
FIGURE 1 Cerebral infarction in the territory of the left middle cerebral artery (MCA). CT scan shows decreased density in the left cerebral hemisphere in the distribution of the MCA.
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the two to seven day-interval and a further increase in the 7 to 21 day-interval. A decline was noted after 21 days. CT showed, on the other hand, little difference in the incidence of positive results between the three groups in this small sample. Unlike thromboembolic cerebral infarction, intracerebral hematomas were detected by CT in all seven patients included in this series (table 2). In all cases the nature of the lesion was also determined, as distinct from infarction, by its high density (fig. 4). The RN studies showed an increased uptake, indistinct from infarction, in two patients only. The remaining five patients showed normal RN studies. Discussion CEREBRAL INFARCTION
The changes shown on CT scan in patients with infarction have been described by New et al.1 and Paxton and Ambrose.2 These authors point to a series of changes based upon the natural history of cerebral infarction. CT obtained in the
FIGURE 2 Cerebral infarction in the territory of the left MCA. RN brain images: anteroposterior view (top), left lateral view (bottom). There is increased uptake of the radionuclide by the brain in the distribution of the left MCA.
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COMPUTERIZED TOMOGRAPHY AND RADIONUCLIDE IMAGING/Garfo et al. TABLE 2 Cerebrovascular Accidents: Results of Images and CT Scans
Ill
Radionuclide
Diagnosis
n
CTT abnormal
Radionuclide imaging abnormal*
Recent cerebral infarction Recent intracerebral hematoma Acute SAH Old cerebrovascular accidents
29
16 (55%)
20 (69%)
7
7 (100%)
2 (28%)
1 3
1 3
0 0
•Does not include results of rapid sequence scintigraphy. SAH = subarachnoid hemorrhage.
first few days after the ictus shows a diffuse low density area involving the cortex and white matter with little or no midline displacement. Studies done more than ten days after the initial episode show a more clearly defined low density area. After a month or more some patients show a well-defined cystic area with CSF density. New1 ascribes the early changes, within hours or days after the onset of infarction, to accompanying cerebral edema. He suggests that necrosis and phagocytosis result in the appearance ten days later of a more well-defined margin and lower density of the lesion as compared to the edema of the earlier stage. He postulates that if the area of necrosis is small, the lesion may become difficult to detect. When it is large, a remaining cavity with CSF density is seen at the site of an old infarct. The incidence of abnormal findings on CT in patients with cerebral infarction was reported to be 48% by Baker et al.3 and 49% by Paxton and Ambrose.2 Our results show a slightly higher figure of 55% in recent infarction. None of our studies showed evidence of deformity of the ventricular system due to cerebral swelling. Davis and Pressman4 also found that the majority of patients with cerebral infarction showed no such swelling. The frequency of abnormal RN studies in patients with cerebral infarction studied during the first week after the onset of symptoms 5 " has been reported to vary between 20% and 40%. Welch et al.12 in a study of 169 radionuclide studies in patients with thromboembolic cerebral infarction reported 32% positive studies during the first week after the ictus and 52% positive findings in studies done later than one week after the ictus. They also indicated a 27% incidence of abnormal studies in the first two days after the episode. Our results of RN imaging show the same trend but the figures in our series are higher due to an artificial bias as indicated earlier. They are higher than our previously published data.12
TABLE 3 Recent Infarction: Results of Radionuclide and CT Scans*
No. of cases
CRAG (n.) CRAG result +
i
Sillfife:
Images
CT + RN +
CT RN +
CT + RN -
CT RN -
10 6 1 5
10 8 3 5
6 3 3 0
3 1 0 1
*CT = computerized tomography. RN = radionuclide static images. CRAG = rapid sequence scintigraphy. + = positive. — = negative.
M
FIGURE 3 Occlusion of right internal carotid artery. Rapid sequence scintigraphy showing arterial phase (top), capillary phase (middle), and venous phase (bottom). There is decreased activity in the right hemisphere in the arterial phase. In the venous phase, there is increased activity in the right hemisphere suggesting collateral flow to the right hemisphere. This has been referred to as the "flipflop" phenomenon.
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It appears, therefore, that the percentage of abnormalities on CT in recent infarction is comparable to RN brain imaging. While this is the case, if one compares the results of the two tests in the same patient, one finds that patients with
VOL. 7, No. 2, MARCH-APRIL
1976
negative CT are not necessarily those who have negative RN imaging, and vice versa. Table 3 shows that in 29 patients with recent infarction, the results of the two tests were not identical in 16 (55%). The significance of this observation is evident. While the two tests yield a comparable percentage of abnormalities, their roles in detection of a lesion are complementary rather than alternative. The three patients evaluated one year after the episode showed abnormalities on CT while the RN images showed no increased uptake. Patients with old strokes are prone to have new strokes. A positive RN uptake would be related to the recent stroke whereas a positive CT could be the result of either the recent or the old stroke, another indication for the complementary role of the two tests. Our results show no relationship between the incidence of abnormalities on CT and the time lapse after the episode. INTRACEREBRAL HEMATOMA
Previous reports have demonstrated the high efficacy of CT in detecting fresh intracerebral hematomas.1-2 The high x-ray attenuation characteristics of clotted blood enable CT scanning to detect 100%2 of intracerebral hematomas and to distinguish them from infarction. Our results in this small series and our experience are in agreement with these findings. Moreover, we have studied three patients with intracerebral hematoma (one of them not included in this series) in whom the clinical diagnosis was one of thromboembolic infarction. It was only after CT that the nature of the lesion was determined. The results of RN brain imaging in patients with intracerebral hematoma in previous reports6' "• 1S~1B show a wide range (107o to 60%) of incidence of abnormal scans. In our experience12 abnormal RN images were seen in 43% of patients with intracerebral hematoma. The results in the current study show a lower percentage (28%) and confirm the superiority of CT over RN imaging in this group of patients. Conclusions The incidence of abnormalities on CT in cases of cerebral infarction is comparable to those of RN imaging. In intracerebral hematoma CT is far superior to RN studies.
TABLE 4 Relationship of Findings on Radionuclide and CT Studies lo Time Interval After Onset of Cerebral Thromboembolic Infarction
FIGURE 4 Right intracerebral hematoma. CT scan shows increased density caused by high x-ray absorbency of clotted blood in the deep portion of the right cerebral hemisphere. The blood clot extended into the lateral ventricle.
Time interval
Total (no.)
Abnormal scans (no.)
% Abnormal studies
Radionuclide imaging 0-2 days 2-7 days 7-21 days >21 days*
32 10 13 4 5
20 6 9 3 2
63 40 69 75 40
CT scan 0-2 days 2-7 days 7-21 days >21 days*
32 8 12 6 6
19 5 7 4
59 63 58 66 50
3
•Includes three patients evaluated one year after a cerebrovascular accident.
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NEUROGENIC REGULATION OF CBF FOLLOWING ISCHEMIA/Zervas et al. The distinction between intracerebral hematoma and cerebral infarction can be made only by CT. Three observations in this study indicate complementary roles for RN brain imaging and CT in evaluation of patients with stroke. (1) While the percentages of abnormalities on both tests were comparable in recent infarction, the results in the same patients were not identical in 55% of the cases. (2) In patients with a recent and an old stroke a positive RN uptake would be the result of the recent insult, while on CT both types of lesions show similar abnormalities. (3) Hemodynamic changes on rapid sequence studies were demonstrated in 38% of 18 patients on whom the test was done. References 1. New PFJ, Scott WR, Schnur JA, et al: Computerized axial tomography with the EMI scanner. Radiology 110:109-123, 1974 2. Paxton R, Ambrose J: The EMI scanner. A brief review of the first 650 patients. Br J Radiol 47:530-565, 1974 3. Baker HL Jr, Campbell JK, Houser OD, et al: Computer assisted tomography of the head. An early evaluation. Mayo d i n Proc 49:17-27 (Jan) 1974
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4. Davis DO, Pressman BD: Computerized tomography of the brain. Radiol Clin North Am 12:297-313 (Aug) 1974 5. Tow RE, Wagner HN, Deland FH, et al: Brain scanning in cerebral vascular disease. JAMA 207:105-108, 1969 6. Glasgow JL, Currier RD, Goodrich JK, et al: Brain scans at varied intervals following CVA. J Nud Med 6:902-916, 1965 7. Morrison RT, Afifi AK, Van Allen MW, et al: Scintiencephalography for the detection and localization of non-neoplastic intracranial lesions. J Nucl Med 6:7-15, 1965 8. Brown A, Zingesser L, Scheinberg LC: Radioactive mercury-labeled chlormerodrin scans in cerebrovascular accidents. Neurology 17:405-411, 1967 9. Oeconomos D: Gammaencephalography in cerebral vascular accidents. Prog Brain Res 30:201-209, 1968 10. Marshall J, Popham MG: Radioactive brain scanning in the management of cerebrovascular disease. J Neurol Neurosurg Psychiat 33:201-204, 1970 11. Molinari GF, Pircher F, Heyman A: Serial brain scanning using technetium 99m in patients with cerebral infarction. Neurology 17:627-636, 1967 12. Welch DM, Coleman RE, Hardin WB, et al: Brain scanning in cerebral vascular disease. A reappraisal. Stroke 6:136-141 (Mar-Apr) 1975 13. Sharma SM, Quinn JL: Brain scans in autopsy proved cases of intracerebral hemorrhage. Arch Neurol 28:270-271, 1973 14. Ojemann RG, Aronow S, Sweet WH: Scanning with positron-emitting isotopes in cerebrovascular disease. Acta Radiol Diagn 5:894-905, 1966 15. Overton MC III, Haynie TP, Snodgrass SR: Brain scans in non-neoplastic intracranial lesions. JAMA 191:431-436, 1965
Neurogenic Regulation of Cerebral Blood Flow Following Ischemia NICHOLAS T.
ZERVAS, M.D., HIROSHI HORI, M.D.,
MAKATO NAGORO, M.D., AND RICHARD WURTMAN, M.D.
SUMMARY To elicit evidence concerning neurogenic control, regional cerebral blood flow determined by measurement of cortical temperature was examined in monkeys. Following three hours of temporary occlusion of the MCA, pressure autoregulation was preserved in all control animals. Presumptive partial chemical sympathectomy, produced by the administration of either L-alpha-
methyl-tyrosine or 3-alpha-dimethyl-tyrosine methyl ester HCI, was associated with loss of pressure autoregulation following 1.5 hours of occlusion of the MCA on only the side of the occlusion. Failure of pressure autoregulation in the treated animals implies that sympathetic control was a partial requirement of proper postischemic pressure autoregulation.
Introduction
we examined regional cerebral blood flow (rCBF) in animals with transient cerebral ischemia. Sympathetic function was altered by interference with the synthesis of norepinephrine. Ischemia was produced by temporary ligation of the middle cerebral artery (MCA). Pressure autoregulation (PAR) was then studied to determine whether impairment of autonomic function would modify the control of the cerebral circulation. In the normal state regional or total CBF remains relatively constant within moderate limits of systemic arterial blood pressure. However, if systolic pressure is greater than 140 mm Hg2 or less than 70 mm Hg,3 CBF may increase or decrease, respectively. PAR is said to be preserved if CBF does not change in response to fluctuations of mean arterial blood pressure (MABP) within this range. In the studies described below, MABP was raised by 20 mm Hg for very short periods to determine whether control of CBF was impaired in these ischemic chemically denervated animals. The results will be discussed in the light of recent discussions of sympathetic nerve-blood flow interactions.
THE NORADRENERGIC NERVE TERMINALS of the cervical sympathetic trunk arborize extensively in the adventitia of cerebral arteries and arterioles.1 One would anticipate that these neural elements should participate in the regulation of the cerebral circulation. However, numerous conflicting reports have generated an unresolved controversy regarding the importance of these cerebral sympathetic fibers (see discussion below). Since the normal state may not offer a satisfactory substrate from which to elicit evidence of neurogenic control, From the Department of Neurosurgery, Beth Israel Hospital and Harvard Medical School, Boston, Massachusetts; and the Department of Nutrition and Food Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts. These studies were supported in part by the US Public Health Services (NS-10459, GM-2019, and HL-15365). Reprint requests to Dr. Zervas, Beth Israel Hospital, 330 Brookline Avenue, Boston, Massachusetts 02215.
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Comparison of computerized tomography and radionuclide imaging in "stroke". M H Gado, R E Coleman, A L Merlis, P O Alderson and K S Lee Stroke. 1976;7:109-113 doi: 10.1161/01.STR.7.2.109 Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1976 American Heart Association, Inc. All rights reserved. Print ISSN: 0039-2499. Online ISSN: 1524-4628
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://stroke.ahajournals.org/content/7/2/109
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MARCH-APRIL VOL. 7
1976 NO. 2
A Journal of Cerebral Circulation Comparison of Computerized Tomography and Radionuclide Imaging in "Stroke".99 MOKHTAR H . GADO, M.D., R. EDWARD C O L E M A N , M.D., ANTHONY L. MERLIS, M.D., PHILIP O. ALDERSON, M.D., AND KIL SOO LEE, M.D.
SUMMARY Forty patients were studied by computerized tomography and by radionuclide brain imaging. The final diagnosis was infarction in 29 patients, intracerebral hematoma in seven, acute SAH in one, and old cerebrovascular accidents in three. CT was far superior to RN in detecting intracerebral hematomas and distinguishing them from cerebral infarction. The results of CT and RN
tests were comparable regarding the percentage of abnormalities. However, the results in the same patients were not identical in 55% of the cases, indicating a complementary role for the two tests. There was no relationship between the frequency of abnormalities on CT and the time lapse after the onset of cerebral infarction. RN uptake was not seen in patients with old cerebrovascular accidents.
SINCE THE INTRODUCTION of computerized tomography (CT) as a noninvasive technique for brain imaging, several reports have discussed its usefulness in patients with stroke. The purpose of this communication is to compare CT and radionuclide brain scanning in patients with cerebrovascular disease.
patients. Three patients admitted for evaluation of late sequelae of a cerebrovascular accident that had occurred one year earlier are included in the last column of table 1. In this study there was a slight inadvertent selection of patients resulting in a slight artificial bias in the results. During the greater part of the period covered in this study there was a single CT unit in operation at our institute. As a result of the inevitable waiting list, some patients with a negative RN study were not studied by CT. It is quite possible, therefore, that a group of patients with negative isotope studies and positive CT was inadvertently omitted from the study. This will be discussed later. CT scans were performed with an EMI scanner, using the standard technique. The x-ray tube was operated at 120 KVP and 33 mA with 13 mm collimation of the beam. The scan was done at a plane of 20° above the orbitomeatal plane. The image consisted of an 80 X 80 matrix in the studies of the first 17 patients. The remaining 23 patients were studied by the 160 X 160 matrix. The RN brain scan was performed utilizing a scintillation camera and the intravenous injection of MmTc-pertechnetate (15 to 20 mCi in 1 to 4 cc of saline). A rapid sequence study was performed at the time of the injection, using a high sensitivity parallel hole collimator. Static brain imaging was performed approximately 30 minutes after injection using a high resolution parallel hole collimator. When necessary, delayed images (two to four hours) were obtained.
Methods There were 40 patients with a final diagnosis of cerebrovascular accident. Each patient was examined by CT and radionuclide (RN) brain imaging. There were 29 cases of recent infarction (28 in the cerebral hemisphere and one in the cerebellum), seven cases of intracerebral hemorrhage, and one with subarachnoid hemorrhage (SAH). The diagnosis of cerebral infarction was made on clinical grounds. The diagnosis of intracerebral hematoma was confirmed by surgery in three cases and by autopsy in two. There were two cases in this series in which the diagnosis of a hematoma was based on the CT scan. The interval between the onset of symptoms and the diagnostic imaging in this group of patients is shown in table 1. The time lapse between CT and RN brain imaging was less than one week in the same patient, with a mean of 1.8 days. As shown in table 1, CT was done in the first two days in 15 patients, between two and seven days after the onset in 13 patients, between seven and 21 days in six patients, and more than 21 days after the onset in six patients. RN studies were done in the first two days in 18 patients, between two and seven days after the episode in 13 patients, between seven and 21 days in four patients, and more than 21 days after the episode in five
Results Of the 29 patients with recent infarction, 16 patients (55%) showed abnormality on the CT scan and 20 (69%) showed abnormality on RN brain imaging (table 2). The abnormality on CT consisted of decreased density of the brain tissue (fig. 1). None of the patients had evidence of brain swelling on CT. Twenty of the patients showed increased up-
From the Neuroradiology Section and the Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway, St. Louis, Missouri 63110. Supported in part by Neuroradiology Training Grant NIH-5-T01-NS0522-08. Reprint requests to Dr. Gado, Associate Professor, Chief, Neuroradiology Section.
109
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TABLE 1 Time Interval Between Cerebrovascular Accident and Imaging Studies Days
CT RN
0-2
2-7
7-21
>21
Total
15 18
13 13
6 4
6 5
40 40
take on radionuclide imaging (fig. 2). Rapid sequence scintigraphy was done on 14 of these patients and showed decreased vascularity in three, a flip-flop phenomenon (fig. 3) in one, and normal results in ten. There was no increased uptake in eight patients with recent infarction. Rapid sequence scintigraphy was done on four of them and showed decreased vascularity in three, all of whom had a positive CT. There were three cases in which both the CT and radionuclide study were negative. Rapid sequence scintigraphy was done on one of these and it also was negative (table 3). Of the three patients evaluated one year after a cerebrovascular accident, none showed increased uptake on radionuclide images. Rapid sequence scintigraphy was done on two of them and showed a flip-flop phenomenon in both. CT was positive in all three cases. The results of RN and CT studies were analyzed in relation to the time interval between the scan and the onset of symptoms in the 29 patients with cerebral infarction (table 4). The studies were divided into four groups in which the time interval was 0 to 2 days, 2 to 7 days, 7 to 21 days, and greater than 21 days, respectively. Radionuclide imaging showed an increase in the percentage of detectable cases in
FIGURE 1 Cerebral infarction in the territory of the left middle cerebral artery (MCA). CT scan shows decreased density in the left cerebral hemisphere in the distribution of the MCA.
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the two to seven day-interval and a further increase in the 7 to 21 day-interval. A decline was noted after 21 days. CT showed, on the other hand, little difference in the incidence of positive results between the three groups in this small sample. Unlike thromboembolic cerebral infarction, intracerebral hematomas were detected by CT in all seven patients included in this series (table 2). In all cases the nature of the lesion was also determined, as distinct from infarction, by its high density (fig. 4). The RN studies showed an increased uptake, indistinct from infarction, in two patients only. The remaining five patients showed normal RN studies. Discussion CEREBRAL INFARCTION
The changes shown on CT scan in patients with infarction have been described by New et al.1 and Paxton and Ambrose.2 These authors point to a series of changes based upon the natural history of cerebral infarction. CT obtained in the
FIGURE 2 Cerebral infarction in the territory of the left MCA. RN brain images: anteroposterior view (top), left lateral view (bottom). There is increased uptake of the radionuclide by the brain in the distribution of the left MCA.
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COMPUTERIZED TOMOGRAPHY AND RADIONUCLIDE IMAGING/Garfo et al. TABLE 2 Cerebrovascular Accidents: Results of Images and CT Scans
Ill
Radionuclide
Diagnosis
n
CTT abnormal
Radionuclide imaging abnormal*
Recent cerebral infarction Recent intracerebral hematoma Acute SAH Old cerebrovascular accidents
29
16 (55%)
20 (69%)
7
7 (100%)
2 (28%)
1 3
1 3
0 0
•Does not include results of rapid sequence scintigraphy. SAH = subarachnoid hemorrhage.
first few days after the ictus shows a diffuse low density area involving the cortex and white matter with little or no midline displacement. Studies done more than ten days after the initial episode show a more clearly defined low density area. After a month or more some patients show a well-defined cystic area with CSF density. New1 ascribes the early changes, within hours or days after the onset of infarction, to accompanying cerebral edema. He suggests that necrosis and phagocytosis result in the appearance ten days later of a more well-defined margin and lower density of the lesion as compared to the edema of the earlier stage. He postulates that if the area of necrosis is small, the lesion may become difficult to detect. When it is large, a remaining cavity with CSF density is seen at the site of an old infarct. The incidence of abnormal findings on CT in patients with cerebral infarction was reported to be 48% by Baker et al.3 and 49% by Paxton and Ambrose.2 Our results show a slightly higher figure of 55% in recent infarction. None of our studies showed evidence of deformity of the ventricular system due to cerebral swelling. Davis and Pressman4 also found that the majority of patients with cerebral infarction showed no such swelling. The frequency of abnormal RN studies in patients with cerebral infarction studied during the first week after the onset of symptoms 5 " has been reported to vary between 20% and 40%. Welch et al.12 in a study of 169 radionuclide studies in patients with thromboembolic cerebral infarction reported 32% positive studies during the first week after the ictus and 52% positive findings in studies done later than one week after the ictus. They also indicated a 27% incidence of abnormal studies in the first two days after the episode. Our results of RN imaging show the same trend but the figures in our series are higher due to an artificial bias as indicated earlier. They are higher than our previously published data.12
TABLE 3 Recent Infarction: Results of Radionuclide and CT Scans*
No. of cases
CRAG (n.) CRAG result +
i
Sillfife:
Images
CT + RN +
CT RN +
CT + RN -
CT RN -
10 6 1 5
10 8 3 5
6 3 3 0
3 1 0 1
*CT = computerized tomography. RN = radionuclide static images. CRAG = rapid sequence scintigraphy. + = positive. — = negative.
M
FIGURE 3 Occlusion of right internal carotid artery. Rapid sequence scintigraphy showing arterial phase (top), capillary phase (middle), and venous phase (bottom). There is decreased activity in the right hemisphere in the arterial phase. In the venous phase, there is increased activity in the right hemisphere suggesting collateral flow to the right hemisphere. This has been referred to as the "flipflop" phenomenon.
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It appears, therefore, that the percentage of abnormalities on CT in recent infarction is comparable to RN brain imaging. While this is the case, if one compares the results of the two tests in the same patient, one finds that patients with
VOL. 7, No. 2, MARCH-APRIL
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negative CT are not necessarily those who have negative RN imaging, and vice versa. Table 3 shows that in 29 patients with recent infarction, the results of the two tests were not identical in 16 (55%). The significance of this observation is evident. While the two tests yield a comparable percentage of abnormalities, their roles in detection of a lesion are complementary rather than alternative. The three patients evaluated one year after the episode showed abnormalities on CT while the RN images showed no increased uptake. Patients with old strokes are prone to have new strokes. A positive RN uptake would be related to the recent stroke whereas a positive CT could be the result of either the recent or the old stroke, another indication for the complementary role of the two tests. Our results show no relationship between the incidence of abnormalities on CT and the time lapse after the episode. INTRACEREBRAL HEMATOMA
Previous reports have demonstrated the high efficacy of CT in detecting fresh intracerebral hematomas.1-2 The high x-ray attenuation characteristics of clotted blood enable CT scanning to detect 100%2 of intracerebral hematomas and to distinguish them from infarction. Our results in this small series and our experience are in agreement with these findings. Moreover, we have studied three patients with intracerebral hematoma (one of them not included in this series) in whom the clinical diagnosis was one of thromboembolic infarction. It was only after CT that the nature of the lesion was determined. The results of RN brain imaging in patients with intracerebral hematoma in previous reports6' "• 1S~1B show a wide range (107o to 60%) of incidence of abnormal scans. In our experience12 abnormal RN images were seen in 43% of patients with intracerebral hematoma. The results in the current study show a lower percentage (28%) and confirm the superiority of CT over RN imaging in this group of patients. Conclusions The incidence of abnormalities on CT in cases of cerebral infarction is comparable to those of RN imaging. In intracerebral hematoma CT is far superior to RN studies.
TABLE 4 Relationship of Findings on Radionuclide and CT Studies lo Time Interval After Onset of Cerebral Thromboembolic Infarction
FIGURE 4 Right intracerebral hematoma. CT scan shows increased density caused by high x-ray absorbency of clotted blood in the deep portion of the right cerebral hemisphere. The blood clot extended into the lateral ventricle.
Time interval
Total (no.)
Abnormal scans (no.)
% Abnormal studies
Radionuclide imaging 0-2 days 2-7 days 7-21 days >21 days*
32 10 13 4 5
20 6 9 3 2
63 40 69 75 40
CT scan 0-2 days 2-7 days 7-21 days >21 days*
32 8 12 6 6
19 5 7 4
59 63 58 66 50
3
•Includes three patients evaluated one year after a cerebrovascular accident.
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NEUROGENIC REGULATION OF CBF FOLLOWING ISCHEMIA/Zervas et al. The distinction between intracerebral hematoma and cerebral infarction can be made only by CT. Three observations in this study indicate complementary roles for RN brain imaging and CT in evaluation of patients with stroke. (1) While the percentages of abnormalities on both tests were comparable in recent infarction, the results in the same patients were not identical in 55% of the cases. (2) In patients with a recent and an old stroke a positive RN uptake would be the result of the recent insult, while on CT both types of lesions show similar abnormalities. (3) Hemodynamic changes on rapid sequence studies were demonstrated in 38% of 18 patients on whom the test was done. References 1. New PFJ, Scott WR, Schnur JA, et al: Computerized axial tomography with the EMI scanner. Radiology 110:109-123, 1974 2. Paxton R, Ambrose J: The EMI scanner. A brief review of the first 650 patients. Br J Radiol 47:530-565, 1974 3. Baker HL Jr, Campbell JK, Houser OD, et al: Computer assisted tomography of the head. An early evaluation. Mayo d i n Proc 49:17-27 (Jan) 1974
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4. Davis DO, Pressman BD: Computerized tomography of the brain. Radiol Clin North Am 12:297-313 (Aug) 1974 5. Tow RE, Wagner HN, Deland FH, et al: Brain scanning in cerebral vascular disease. JAMA 207:105-108, 1969 6. Glasgow JL, Currier RD, Goodrich JK, et al: Brain scans at varied intervals following CVA. J Nud Med 6:902-916, 1965 7. Morrison RT, Afifi AK, Van Allen MW, et al: Scintiencephalography for the detection and localization of non-neoplastic intracranial lesions. J Nucl Med 6:7-15, 1965 8. Brown A, Zingesser L, Scheinberg LC: Radioactive mercury-labeled chlormerodrin scans in cerebrovascular accidents. Neurology 17:405-411, 1967 9. Oeconomos D: Gammaencephalography in cerebral vascular accidents. Prog Brain Res 30:201-209, 1968 10. Marshall J, Popham MG: Radioactive brain scanning in the management of cerebrovascular disease. J Neurol Neurosurg Psychiat 33:201-204, 1970 11. Molinari GF, Pircher F, Heyman A: Serial brain scanning using technetium 99m in patients with cerebral infarction. Neurology 17:627-636, 1967 12. Welch DM, Coleman RE, Hardin WB, et al: Brain scanning in cerebral vascular disease. A reappraisal. Stroke 6:136-141 (Mar-Apr) 1975 13. Sharma SM, Quinn JL: Brain scans in autopsy proved cases of intracerebral hemorrhage. Arch Neurol 28:270-271, 1973 14. Ojemann RG, Aronow S, Sweet WH: Scanning with positron-emitting isotopes in cerebrovascular disease. Acta Radiol Diagn 5:894-905, 1966 15. Overton MC III, Haynie TP, Snodgrass SR: Brain scans in non-neoplastic intracranial lesions. JAMA 191:431-436, 1965
Neurogenic Regulation of Cerebral Blood Flow Following Ischemia NICHOLAS T.
ZERVAS, M.D., HIROSHI HORI, M.D.,
MAKATO NAGORO, M.D., AND RICHARD WURTMAN, M.D.
SUMMARY To elicit evidence concerning neurogenic control, regional cerebral blood flow determined by measurement of cortical temperature was examined in monkeys. Following three hours of temporary occlusion of the MCA, pressure autoregulation was preserved in all control animals. Presumptive partial chemical sympathectomy, produced by the administration of either L-alpha-
methyl-tyrosine or 3-alpha-dimethyl-tyrosine methyl ester HCI, was associated with loss of pressure autoregulation following 1.5 hours of occlusion of the MCA on only the side of the occlusion. Failure of pressure autoregulation in the treated animals implies that sympathetic control was a partial requirement of proper postischemic pressure autoregulation.
Introduction
we examined regional cerebral blood flow (rCBF) in animals with transient cerebral ischemia. Sympathetic function was altered by interference with the synthesis of norepinephrine. Ischemia was produced by temporary ligation of the middle cerebral artery (MCA). Pressure autoregulation (PAR) was then studied to determine whether impairment of autonomic function would modify the control of the cerebral circulation. In the normal state regional or total CBF remains relatively constant within moderate limits of systemic arterial blood pressure. However, if systolic pressure is greater than 140 mm Hg2 or less than 70 mm Hg,3 CBF may increase or decrease, respectively. PAR is said to be preserved if CBF does not change in response to fluctuations of mean arterial blood pressure (MABP) within this range. In the studies described below, MABP was raised by 20 mm Hg for very short periods to determine whether control of CBF was impaired in these ischemic chemically denervated animals. The results will be discussed in the light of recent discussions of sympathetic nerve-blood flow interactions.
THE NORADRENERGIC NERVE TERMINALS of the cervical sympathetic trunk arborize extensively in the adventitia of cerebral arteries and arterioles.1 One would anticipate that these neural elements should participate in the regulation of the cerebral circulation. However, numerous conflicting reports have generated an unresolved controversy regarding the importance of these cerebral sympathetic fibers (see discussion below). Since the normal state may not offer a satisfactory substrate from which to elicit evidence of neurogenic control, From the Department of Neurosurgery, Beth Israel Hospital and Harvard Medical School, Boston, Massachusetts; and the Department of Nutrition and Food Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts. These studies were supported in part by the US Public Health Services (NS-10459, GM-2019, and HL-15365). Reprint requests to Dr. Zervas, Beth Israel Hospital, 330 Brookline Avenue, Boston, Massachusetts 02215.
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Comparison of computerized tomography and radionuclide imaging in "stroke". M H Gado, R E Coleman, A L Merlis, P O Alderson and K S Lee Stroke. 1976;7:109-113 doi: 10.1161/01.STR.7.2.109 Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1976 American Heart Association, Inc. All rights reserved. Print ISSN: 0039-2499. Online ISSN: 1524-4628
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