European Journal of Radiology 83 (2014) 163–166

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Whole-body MRI vs. CT for staging lymphoma: Patient experience Hugo J.A. Adams a , Thomas C. Kwee a,∗ , Malou A. Vermoolen a , Inge Ludwig b , Marc B. Bierings c , Rutger A.J. Nievelstein a a b c

Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands Department of Hematology, University Medical Center Utrecht, Utrecht, The Netherlands Department of Pediatric Hematology, University Medical Center Utrecht, Utrecht, The Netherlands

a r t i c l e

i n f o

Article history: Received 22 June 2013 Received in revised form 22 August 2013 Accepted 7 October 2013 Keywords: CT Lymphoma Patient experience Whole-body MRI

a b s t r a c t Objective: To assess and compare patient experience of whole-body magnetic resonance imaging (MRI) to that of computed tomography (CT) for staging newly diagnosed lymphoma. Materials and methods: A total of 36 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and CT for staging purposes. Patients were asked to fill in a short questionnaire with regard to the burden and experience of the examination on a Likert scale (range 1–4). Wilcoxon signed rank tests were used to determine statistically significant differences in patient (dis)comfort between the two examinations. Results: Patients reported to be significantly (P = 0.007) less worried before undergoing whole-body MRI compared to CT. Patients also experienced whole-body MRI as significantly (P = 0.010) less unpleasant and felt significantly (P = 0.003) better shortly after the scan. The necessary preparations before CT scanning (i.e. insertion of intravenous line, drinking of contrast fluid), which are not required for whole-body MRI, were reported to be a considerable burden. Conclusion: In this study in patients with newly diagnosed lymphoma, whole-body MRI was experienced as a more patient-friendly technique than CT. © 2013 Elsevier Ireland Ltd. All rights reserved.

1. Introduction Whole-body magnetic resonance imaging (MRI) is an emerging technique for the evaluation of several types of cancer, including lymphoma [1–9], and is about to enter the clinical arena as a feasible alternative to more established whole-body cross-sectional imaging modalities like computed tomography (CT). Whole-body MRI has several advantages over CT. First, whole-body MRI does not use any ionizing radiation, which makes it particularly advantageous for the evaluation of pediatric and pregnant patients and for repeat follow-up surveillance of cancer patients in general [10]. Second, thanks to its high soft-tissue contrast and the possibility to implement functional sequences such as diffusion-weighted imaging (DWI) in a whole-body MRI examination [11,12], it is possible to perform a diagnostic whole-body MRI acquisition without using any contrast agents in specific clinical settings (e.g. in staging of lymphoma [4,5]), whereas CT requires administering intravenous contrast media (which may cause allergic reactions

∗ Corresponding author at: University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Tel.: +31 88 7556687; fax: +31 30 2581098. E-mail address: [email protected] (T.C. Kwee). 0720-048X/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejrad.2013.10.008

[13]). Third, whole-body MRI generally does not require ingestion of an oral contrast medium as is usually necessary with CT. On the other hand, acquisition time of whole-body MRI is considerably longer (up to 1 h) compared to that of CT (usually less than 2 min), which may be an issue in cancer patients who may not be able to tolerate such a long examination. MRI-related claustrophobia may also be an issue. Furthermore, there are several MRI contraindications, including cadiac pacemakers, implantable defibrillators, neurostimulators, or insuline or other infusion pumps [14,15]. Finally, current MRI systems produce considerable acoustic noise [16]. Besides comparative studies on diagnostic and prognostic accuracies, it is important to assess and compare patient experience of undergoing whole-body MRI relative to CT. Such information is crucial for the successful clinical implementation of whole-body MRI. The necessity for the imaging community to evaluate diagnostic procedures, including whole-body MRI, from the perspective of the patient has also been emphasized by the theme of the 2012 Annual Meeting of the Radiological Society of North America (RSNA) (“Patients first”) and the keynote lecture by RSNA 2012 president George S. Bisset, III, MD (“It is in our best interest to make our procedures more patient-friendly and to observe care more often through the eyes of the patient rather than through our own”) [17]. The purpose of this prospective study was therefore to assess and compare patient experience

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of whole-body MRI to that of CT for staging newly diagnosed lymphoma.

T1 W, 12–15 min for T2W-STIR, and 20–25 min for DWI. No oral or intravenous contrast media were applied for whole-body MRI. 2.3. CT

2. Methods 2.1. Patients This prospective study was institutional review board approved and all patients provided written informed consent. The parent(s) or guardian(s) of all patients under 18 years of age also provided written informed consent. Inclusion criteria were: patients aged 8 years or older who were clinically scheduled to undergo CT for staging newly diagnosed (histologically proven) Hodgkin or non-Hodgkin lymphoma, written informed consent before start of the study, and the possibility to perform whole-body MRI within 15 days of CT, before therapy. Exclusion criteria were: patients with a general contraindication for MRI (including cardiovascular pacemakers, claustrophobia), patients physically or psychologically unable to undergo a whole-body MRI examination, patients with a previous malignancy, patients who were pregnant or nursing, and patients in whom therapy had already started.

2.2. Whole-body MRI Whole-body MRI was performed at 1.5T (Achieva, Philips Healthcare, Best, The Netherlands. First, coronal multishot turbo spin-echo T1-weighted (T1W) and T2-weighted short inversion time inversion recovery (T2W-STIR) turbo spin-echo whole-body images were acquired using the built-in body coil for signal reception. Second, axial single-shot spin-echo echo-planar imaging diffusion-weighted images (b-values of 0 and 1000 s/mm2 ) of the head/neck, chest, abdomen, and pelvis were acquired using phasedarray surface coils for signal reception (Fig. 1). Scan parameters are listed in Table 1. Total actual scan times were 12–15 min for

CT scanning of the neck, chest, abdomen, and pelvis was performed using 16- and 64-slice CT scanners (Philips Brilliance, Philips Healthcare, Best, The Netherlands). All patients ingested an oral contrast agent (Telebrix Gastro, Guerbet, The Netherlands) and received an intravenous non-ionic iodinated contrast agent (Ultravist 300, Schering, Berlin, Germany) before scanning. The administered amount of CT contrast agents was adjusted according to age and weight. CT scanning was done using two volumes, with the first volume including the neck and chest in the arterial phase, and the second volume including the abdomen and pelvis in the portal venous phase (Fig. 1). In adults, tube voltage and tube setting were 120 kV and 130 mAs for the head/neck and chest region and 120 kV and 200 mAs for the abdominal and pelvic region with application of automatic tube current modulation. In children, tube voltage and tube setting ranged between 90–120 kV and 50–70 mAs, depending on the patients’ height and weight. No automatic tube current modulation was used in children. The computed tomography dose index volume (CTDIvol) ranged between 3.0 and 5.5 mGy in children. CT acquisition time (i.e. the time it took to scan two volumes) was less than 2 min. All CT images were acquired with a slice thickness/increment of 1–1.5/0.7–0.8 mm, and were reconstructed to contiguous axial 5-mm slices. 2.4. Questionnaire All patients were asked to fill in a short questionnaire on the day of the whole-body MRI and CT examinations (usually directly after the examination). The questionnaire included questions with regard to the burden and experience of the whole-body MRI and CT examinations and patient wellbeing before, during and shortly after scanning (Table 2). The questionnaire also evaluated the patients’

Fig. 1. Coronal T1W (a), T2W-STIR (b), and maximum intensity projection greyscale inverted diffusion-weighted (c) images, and coronal CT images of the head/neck (d), chest (e), and abdomen/pelvis (f) in a 67-year-old male with follicular lymphoma. Both T1W, T2W-STIR, DWI, and CT show extensive supra- and infradiaphragmatic lymph node involvement (arrows).

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Table 1 MRI parameters.

Plane Repetition time (ms) Echo time (ms) Inversion time (ms) Slice thickness/gap (mm) Field of view (mm2 ) Acquisition matrix Number of signal averages Partial Fourier (half scan) factor Parallel acquisition (SENSitivity Encoding) factor Turbo spin echo factor Echo planar imaging factor Acquired voxel size (mm3 ) Reconstructed voxel size Free breathing (FB), breath hold (BH) or respiratory triggering (RT) Total craniocaudal coverage (cm) b-Values (s/mm2 ) Total effective scan time Total actual scan time

T1W

T2W-STIR

DWI

Coronal 537 18 NA 6/1 530 × 265 208 × 287 1 NA NA 7 NA 1.27 × 1.85 × 6.00 1.04 × 1.04 × 6.00 FB and BHb 185.5 NA 5 min 29 s 12–15 min

Coronal 2444 64 165 6/1 530 × 265 336 × 120 2 NA NA 30 NA 1.58 × 2.21 × 6.00 1.04 × 1.04 × 6.00 FB and RT‡ 185.5 NA 5 min 8 s 12–15 min

Axial 8612a or 6962b 78 180 4/0 450 × 360 128 × 81 3 0.651 2 NA 43 3.52 × 4.50 × 4.00 1.76 × 1.76 × 1.76 FB 96.0 0 and 1000 4 min 4 sa or 3 min 20 sb per station 20–25 min

Notes: NA: not applicable. a Head/neck station. b Chest/abdominal/pelvic stations.

opinion about the CT preparation (insertion of intravenous line, drinking of contrast fluid) (Table 2). In addition, pediatric patients were asked two more questions about fear and pain during the examination (Table 2). Questions were answered on a four-point Likert scale.

performed). P-values less than 0.05 were considered to indicate a significant difference. Statistical analyses were executed using the Statistical Package for the Social Sciences version 17.0 software (SPSS Inc., Chicago, IL).

2.5. Statistical analysis

3. Results

Descriptive statistics (including mean, standard deviation, median, and range) of the responses to the different questions for whole-body MRI and CT were calculated. Whole-body MRI scores and CT scores were statistically compared using (nonparametric) Wilcoxon signed rank tests (if pairwise comparisons could be

A total of 36 consecutive patients (21 males and 15 females, 32 adults and 4 children, mean age 50.2 ± 19.4 years, age range 12–78 years) were included, of whom 5 patients had Hodgkin lymphoma and 31 patients had non-Hodgkin lymphoma. All CT scans were performed before whole-body MRI. The mean interval between CT

Table 2 Questions listed on the questionnaire, number of patients, scores (mean ± standard deviation [SD], median, and range) for whole-body MRI and CT, and results of Wilcoxon test comparing whole-body MRI and CT scores. Question

Were you worried to undergo the examination? 1 = absolutely not; 2 = not; 3 = a little; 4 = a lot How did you experience the preparation of the CT scan (insertion of intravenous line, ingestion of contrast? 1 = not unpleasant at all; 2= not so unpleasant; 3 = unpleasant; 4 = very unpleasant Were you afraid during the examination?a 1 = not afraid at all; 2 = not so afraid; 3 = afraid; 4 = very afraid Did the examination hurt?a 1 = not painful at all; 2 = a bit painful; 3 = painful; 4 = very painful How did you experience the examination? 1 = not unpleasant at all; 2 = not so unpleasant; 3 = unpleasant; 4 = very unpleasant How did you feel directly after the scan? 1 = very well; 2 = quite well; 3 = not so well; 4 = not well at all

No. of patients

Whole-body MRI

CT

P-value of Wilcoxon test

Mean ± SD

Median

Range

Mean ± SD

Median

Range

N = 36

1.472 ± 0.654

1

1–3

1.833 ± 0.845

2

1–3

0.007b

N = 36

NA

NA

NA

2.278 ± 0.882

2

1–4

NA

N=4

1.250 ± 0.500

1

1–2

1.250 ± 0.500

1

1–2

c

N=4

1.000 ± 0.000

1

1–1

2.250 ± 0.957

2

1–3

c

N = 36

1.486 ± 0.579

1

1–3

1.833 ± 0.737

2

1–3

0.010b

N = 36

1.639 ± 0.487

2

1–2

1.931 ± 0.563

2

1–3

0.003b

Notes: NA: not applicable. a Question for pediatric patients only (i.e. patients below 18 years of age). b Significantly more positive scores (i.e. in terms of concerns before the examination, experiencing the actual examination, or wellbeing after the examination) for whole-body MRI compared to CT. c Numbers too low to test for significant differences.

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and whole-body MRI was 8.2 days (standard deviation 9.2 days, range 0–34 days). Table 2 shows the results of the questionnaires. Patients reported to be significantly (P = 0.007) less worried before undergoing whole-body MRI compared to CT. Patients also experienced whole-body MRI as significantly (P = 0.010) less unpleasant and felt significantly (P = 0.003) better shortly after the scan. Although the low number of included pediatric patients precluded statistical comparisons in this subpopulation, pediatric patients reported an equal amount of anxiety for both scans, while whole-body MRI was generally experienced as less painful than CT. The necessary preparations before CT scanning (i.e. insertion of intravenous line, ingestion of contrast medium), which are not required for whole-body MRI in staging of lymphoma, were reported to be a considerable burden. 4. Discussion The results of this study suggest that patients with newly diagnosed lymphoma prefer whole-body MRI over CT. Patients reported to be less worried before, to experience less discomfort during, and to feel better after the whole-body MRI examination. On top of that, the present study shows that the preparation of CT (intravenous line insertion and oral contrast ingestion), which is not needed in whole-body MRI in staging of lymphoma, is seen as a considerable burden by patients. Several studies have already shown that whole-body MRI is a clinically feasible technique for staging lymphoma that provides diagnostic accuracy comparable to CT and 18 F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) [4–9]. For example, one study in 31 patients with newly diagnosed lymphoma reported that whole-body MRI (without DWI and with DWI) equals staging using CT in the majority of patients, whereas whole-body MRI never understaged relative to CT. Furthermore, whole-body MRI mostly correctly overstaged relative to CT, with a possible advantage of using DWI [4]. The positive patient experience of whole-body MRI (relative to CT) supports its further clinical implementation. To the best of our knowledge, no previous studies have investigated patient experience of whole-body MRI and compared it to other cross-sectional imaging modalities like CT or PET. On the other hand, patient experience has been the subject of active investigation in several other areas. For example, there are several studies that compared patient experience of CT colonography and MR colonography to that of conventional colonoscopy [18,19]. The present study has several limitations. First, only patients with newly diagnosed lymphoma were included, and the results of this study may not apply to other patient populations. Second, only a limited number of children was included. Future studies should further investigate patient experience of whole-body MRI in a larger pediatric sample size. Third, patient experience of wholebody MRI was compared to that of CT and not to that of FDG-PET or FDG-PET/CT. However, CT is still the most commonly used imaging modality for staging newly diagnosed lymphoma [20], and the benefit of performing baseline FDG-PET has not been proven yet [21]. For this reason, baseline FDG-PET is not routinely performed in our hospitals, and this particular comparison was not done. Fourth, the majority of the whole-body MRI scans were acquired after CT, and this may have introduced some bias to the results. However, scheduling of the whole-body MRI and CT examinations was influenced by logistic circumstances, and it was not possible to randomize the order of the scans in this study. Fifth, the applied questionnaires were short, and it may be worthwhile for future studies to further explore specific reasons that provided

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