Comprehensive imaging of tumor recurrence in breast cancer patients using whole-body MRI at 1.5 and 3 T compared to FDG-PET-CT

PURPOSE: To compare the diagnostic accuracy for the detection of tumor recurrence in breast cancer patients using whole-body-MRI (WB-MRI) at 1.5 or 3T compared to FDG-PET-CT. MATERIALS AND METHODS: Thirty-three female patients with breast cancer and suspicion of recurrence underwent FDG-PET-CT and WB-MRI. Coronal T1w-TSE- and STIR-sequences, HASTE-imaging of the lungs, contrast-enhanced T1w- and T2w-TSE-sequences of the liver, brain and abdomen were performed, using a WB-MRI-scanner at 1.5 (n=23) or 3T (n=10). Presence of local recurrence, lymph node involvement and distant metastatic disease was assessed using clinical and radiological follow-up as a standard of reference. RESULTS: Tumor recurrence was found in 20 of 33 patients. Overall 186 malignant foci were detected with WB-MRI and PET-CT. Both modalities revealed two recurrent tumors of the breast. PET-CT detected more lymph node metastases (n=21) than WB-MRI (n=16). WB-MRI was more precise in the detection of distant metastases (n=154 versus n=147). Sensitivity was 93% (172/186) and 91% (170/186) for WB-MRI and PET-CT, specificity was 86% (66/77) and 90% (69/77), respectively. Examination times for WB-MRI at 1.5 and 3T were 51 and 43 min, respectively, examination time for PET-CT was 103 min. CONCLUSION: WB-MRI and PET-CT are useful for the detection of tumor recurrence in the follow-up of breast cancer. WB-MRI is highly sensitive to distant metastatic disease. PET-CT is more sensitive in detecting lymph node involvement. Tumor screening with WB-MRI is feasible at 1.5 and 3T, scan time is further reduced at 3T with identical resolution.     

Comparison of MRI (including SS SE-EPI and SPIO-enhanced MRI) and FDG-PET/CT for the detection of colorectal liver metastases

Fluoro-18-deoxyglucose positron emission tomography computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI), including unenhanced single-shot spin-echo echo planar imaging (SS SE-EPI) and small paramagnetic iron oxide (SPIO) enhancement, were compared prospectively for detecting colorectal liver metastases. Twenty-four consecutive patients suspected for metastases underwent MRI and FDG-PET/CT. Fourteen patients (58%) had previously received chemotherapy, including seven patients whose chemotherapy was still continuing to within 1 month of the PET/CT study. The mean interval between PET/CT and MRI was 10.2 ± 5.2 days. Histopathology (n = 18) or follow-up imaging (n = 6) were used as reference. Seventy-seven metastases were detected. In nine patients, MRI and PET/CT gave concordant results. Sensitivities for unenhanced SS SE-EPI, MRI without SS SE-EPI and FDG-PET/CT were, respectively, 100% (p = 9 × 10⁻¹⁰ vs PET, p = 8 × 10⁻³ vs MRI without SS SE-EPI), 90% (p = 2 × 10⁻⁷ vs PET) and 60%. PET/CT sensitivity dropped significantly with decreasing size, from 100% in lesions larger than 20 mm (identical to MRI), over 54% in lesions between 10 and 20 mm (p = 3 × 10⁵ versus unenhanced SS SE-EPI), to 32% in lesions under 10 mm (p = 6 × 10⁻⁵ versus unenhanced SS SE-EPI). Positive predictive value of PET was 100% (identical to MRI). MRI, particularly unenhanced SS SE-EPI, has good sensitivity and positive predictive value for detecting liver metastases from colorectal carcinoma. Its sensitivity is better than that of FDG-PET/CT, especially for small lesions.     

基于CT/MRI/PET-CT进行鼻咽癌大体肿瘤区及淋巴结勾画的对照研究

目的:比较基于计算机体层成像(CT)、磁共振成像(MRI)、 18氟-脱氧葡萄糖正电子发射计算机断层显像( 18F-FDG PET-CT)3种图像勾画鼻咽癌(NPC)大体肿瘤靶区(GTV)及淋巴结的差异,并以MRI为参考研究基于PET自动勾画NPC GTV的最佳标准摄取值(SUV)。 ...     

MRI全景矩阵成像技术在全身骨转移瘤诊断中的价值

目的 探讨全景矩阵成像(TIM)技术对全身骨转移瘤的诊断价值.资料与方法 对25例恶性肿瘤患者采用单光子发射计算机断层显像(SPECT)进行全身骨扫描与TIM技术全身MRI扫描,对两种检查方法进行评价比较.结果 25例中,MRI-TIM及SPECT共检出23例63个病灶,其中恶性54个、良性9个,TIM正确诊断50个转移瘤病灶,敏感度为93%(50/54),特异度为67%(6/9),阳性预测值为94%(50/53),阴性预测值为60%(6/10).SPECT正确诊断47个病灶,敏感度为87%(47/54),特异度为56%(5/9),阳性预测值为92%(47/51),阴性预测值为42%(5/12).两种检查方法的敏感度与特异度之间的差异均无统计学意义(P值分别为0.077和0.643).全身MRI的诊断准确率为89%(56/63),SPECT的诊断准确率为83%(52/63),两者之间的差异有统计学意义(P=0.000).结论 SPECT与TIM能有效地检出全身骨转移癌灶,但TIM对骨髓病变有较高的空间分辨率,比SPECT的诊断正确率更高.     

PET/CT和MRI在多发性骨髓瘤中的应用与进展

多发性骨髓瘤（MM）是一种恶性B细胞肿瘤,其主要累及骨髓,部分也可出现髓外浸润。影像学检查是全面评估MM不可或缺的手段,X射线与CT对病灶的检出率低、定量能力差。PET/CT与MRI对MM的评估具有较大的价值,特别是18F-FDG及其他新型分子探针,全身扩散加权成像、动态增强MRI及水脂分离等MRI新技术。笔者就PET/CT及MRI在MM中的应用与进展进行综述。     

MRI and 18F-fluorodeoxyglucose positron emission tomography in hemimegalencephaly

We report hemimegalencephaly in a 44-year-old woman with mental retardation, epilepsy and a mild hemiparesis. In addition to typical findings on MRI, 2-deoxy-2[¹⁸F]fluorodeoxyglucose positron-emission tomography (PET) demonstrated glucose hypometabolism of the affected hemisphere. The results of PET have been coregistered with morphological information from the MRI studies by image fusion. Received: 14 December 1999/Accepted: 15 February 2000     

Whole-body MRI and PET-CT in the management of cancer patients

Mortality rate, prognosis, and treatment outcome of cancer patients depend strongly on the detection of malignancy at an early stage and efficient monitoring of the disease. Multimodality diagnostic approaches are now widely applied for tumor detection, staging, and follow-up. However, the introduction of whole-body imaging modalities into clinical practice has substantially expanded diagnostic options. PET-CT has increased diagnostic accuracy by providing “anatometabolic” information by fusing tumor glucose-uptake measures from the PET examination and accurate delineation of anatomical structures given by spiral CT. Since PET-CT is associated with high doses of ionizing radiation, it is used in mainly tumor staging and screening within the scope of tertiary prevention. Here promising results have been reported for various tumor entities. MRI provides excellent tissue contrast, detailed morphological information and lack of ionizing radiation. MRI has been employed for the assessment of focal pathologies in specific anatomical regions. Whole-body MRI scanners using multiple receiver channels with parallel acquisition techniques now allow tumor screening from head to toe within substantially shorter examination times and without compromises in image resolution. We report our experience with these two novel techniques and discuss their benefits and drawbacks in terms of systemic tumor screening.     

椎体淋巴瘤MRI及PET临床应用价值

目的探讨椎体淋巴瘤MRI及正电子发射体层成像(PET)的影像特征及临床应用价值。资料与方法回顾性分析经病理证实的15例椎体淋巴瘤患者的MRI和PET表现,原发性骨淋巴瘤6例,继发性9例。结果MRI:原发性6例均为单一椎体压缩性骨折伴局部硬膜外和/或椎体旁软组织肿块,软组织范围超过病变椎体;继发性9例均为多椎体压缩性改变,7例伴硬膜外和/或椎体旁软组织肿块。椎体病变T1WI呈等或混杂信号,T2WI呈稍高信号。软组织肿块T1WI呈等/低信号,T2WI呈稍高信号,明显均匀强化5例,轻度均匀强化8例。PET:原发性6例均为术后PET检查,1例术后2个月显示局部复发,5例无异常;继发性9例(术前6例、术后3例)PET显示多椎体、淋巴结及脾葡萄糖代谢异常增高。结论椎体原发性淋巴瘤多为单椎体病变;继发性常为多椎体受累,两者均可伴硬膜外和/或椎体旁软组织肿块。椎体淋巴瘤MRI、PET表现无特异性,MRI能清晰显示椎管内病灶与脊髓的关系,PET对鉴别原发性与继发性淋巴瘤有重要价值。     

The impact of image fusion in resolving discrepant findings between FDG-PET and MRI/CT in patients with gynaecological cancers

This study was performed to prospectively investigate the impact of image fusion in resolving discrepant findings between fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) or X-ray computed tomography (CT) in patients with gynaecological cancers. Discrepant findings were defined as lesions where the difference between the FDG-PET and MRI/CT images was assigned a value of at least 2 on a 5-point probability scale. The FDG-PET and MRI/CT images were taken within 1 month of each other. Image fusion between FDG-PET and CT was performed by automatic registration between the two images. During an 18-month period, 34 malignant lesions and seven benign lesions from 32 patients who had undergone either surgical excision or a CT-guided histopathological investigation were included for analysis. Among these cases, image fusion was most frequently required to determine the nature and/or the extent of abdominal and pelvic lesions (28/41, 68%), especially as regards peritoneal seeding (8/41, 20%). Image fusion was most useful in providing better localisation for biopsy (16/41, 39%) and in discriminating between lesions with pathological versus physiological FDG uptake (12/41, 29%). Image fusion changed the original diagnosis based on MRI/CT alone in 9/41 lesions (22%), and the original diagnosis based on FDG-PET alone in 5/41 lesions (12%). It led to alteration of treatment planning (surgery or radiotherapy) in seven of the 32 patients (22%). In patients with gynaecological cancers, the technique of image fusion is helpful in discriminating the nature of FDG-avid lesions, in effectively localising lesions for CT-guided biopsy and in providing better surgical or radiotherapy planning.     

Screening for bone metastases: whole-body MRI using a 32-channel system versus dual-modality PET-CT

The diagnostic accuracy of screening for bone metastases was evaluated using whole-body magnetic resonance imaging (WB-MRI) compared with combined fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) (FDG-PET-CT). In a prospective, blinded study, 30 consecutive patients (18 female, 12 male; 24–76 years) with different oncological diseases and suspected skeletal metastases underwent FDG-PET-CT as well as WB-MRI with the use of parallel imaging (PAT). With a 32-channel scanner, coronal imaging of the entire body and sagittal imaging of the complete spine was performed using T1-weighted and short tau inversion recovery (STIR) sequences in combination. PET-CT was conducted using a low-dose CT for attenuation correction, a PET-emission scan and diagnostic contrast-enhanced CT scan covering the thorax, abdomen and pelvis. Two radiologists read the MRI scans, another radiologist in combination with a nuclear medicine physician read the PET-CT scans, each in consensus. The standard of reference was constituted by radiological follow-up within at least 6 months. In 28 patients, 102 malignant and 25 benign bone lesions were detected and confirmed. WB-MRI showed a sensitivity of 94% (96/102), PET-CT exams achieved 78% (79/102; P<0.001). Specificities were 76% (19/25) for WB-MRI and 80% (20/25) for PET-CT (P>0.05). Diagnostic accuracy was 91% (115/127) and 78% (99/127; P<0.001), respectively. Cut-off size for the detection of malignant bone lesions was 2 mm for WB-MRI and 5 mm for PET-CT. WB-MRI revealed ten additional bone metastases due to the larger field of view. In conclusion, WB-MRI and FDG-PET-CT are robust imaging modalities for a systemic screening for metastatic bone disease. PAT allows WB-MRI bone marrow screening at high spatial resolution and with a diagnostic accuracy superior to PET-CT.     

PET/MRI融合显像在脑胶质瘤诊断和治疗中的研究进展

脑胶质瘤发病率较高,是颅内最常见的原发肿瘤。MRI技术在脑胶质瘤分级、手术定位和术后放疗靶区勾画中有着重要的作用。但是,越来越多的研究发现,MRI在肿瘤显像方面仍存在局限性,如准确确定肿瘤边界。PET利用组织代谢原理进行功能显像,有利于发现增殖活跃的肿瘤组织。PET与MRI图像的融合,实现了解剖与功能共同显像,为提高脑胶质瘤诊断的准确性提供了一条新途径。     

Balo's concentric sclerosis followed by MRI and positron emission tomography

We report a case of Balo's concentric sclerosis diagnosed in vivo by characteristic MRI changes and stereotactic biopsy. Follow-up after 6 months of immunosuppressive treatment demonstrated virtually complete clinical remission, reduction of the white matter lesions on MRI and normalisation of regional cerebral glucose metabolism as assessed by positron emission tomography not only in white matter but also in the cerebral grey matter structures with input from the affected regions.     

Whole-body MRI for the staging and follow-up of patients with metastasis

The advent of whole-body MRI (WB-MRI) has introduced tumor imaging with a systemic approach compared to established sequential, multi-modal diagnostic algorithms. Hardware innovations, such as the introduction of multi-receiver channel whole-body scanners at 1.5 T and recently 3 T, combined with acquisition acceleration techniques, have made high resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution and contrast media dynamics can be combined with whole-body anatomic coverage in a multi-planar imaging approach. More flexible protocols, e.g. including T1-weighted TSE- and STIR-imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen can be performed within less than 45 min.For initial tumor staging PET-CT as a competing whole-body modality in oncologic imaging has proved more accurate for the definition of T-stage and lymph node assessment, using the additional metabolic information of PET for the assessment of tumor viability and therapy response. However, new applications, such as MR-whole-body diffusion imaging, may significantly increase sensitivity in near future. WB-MRI has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and it is especially useful as a radiation-free alternative for the surveillance of tumor patients with multiple follow-up exams. Furthermore, it has been introduced as a whole-body bone marrow screening application. Within this context WB-MRI is highly accurate for the detection of skeletal metastases and staging of hematologic diseases, such as multiple myeloma or lymphoma. This article summarizes recent developments and applications of WB-MRI and highlights its performance within the scope of systemic oncologic staging and surveillance.     

2-[Fluorine-18]-fluoro-2-deoxy-<Emphasis Type="SmallCaps">d</Emphasis>-glucose positron emission tomography/computed tomography versus whole-body diffusion-weighted MRI for detection of malignant lesions: initial experience

Objectives The new magnetic resonance whole body diffusion-weighted imaging with background body signal suppression (DWIBS) uses short tau inversion recovery-echo planar imaging sequence under normal respiration. DWIBS is different from 2-[fluorine-18]-fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET) imaging in technology, but their images are similar. We compared the two modalities regarding the detection and characterization of malignant tumors. Methods DWIBS and ¹⁸F-FDG PET/computed tomography (CT) were performed on 16 cancer patients on the same day. The diagnoses were the following: lung cancer (n = 12), colon cancer (n = 2), breast cancer (n = 1), and pulmonary metastasis (n = 1). A total of 27 malignant tumors (15 lung cancer, 5 pulmonary metastases of parathyroid cancer, 3 pulmonary metastases of lung cancer, 3 colon cancer, 1 breast cancer) and seven reference organs around malignant lesions (two liver regions, four normal lymph nodes, one muscle region) were evaluated visually and quantitatively using the apparent diffusion coefficient (ADC) (×10⁻³ mm²/s) and standardized uptake value (SUV). Results Twenty-five (92.6%) of the 27 malignant lesions were detected visually with DWIBS imaging in contrast to 22 malignant tumors (81.5%) with ¹⁸F-FDG PET/CT imaging. The quantitative evaluation showed that there was a significant difference between the mean SUVs of the reference organs (n = 7, 1.48 ± 0.62) and the malignant (n = 22, 5.36 ± 2.80) lesions (P < 0.01). However, there was no significant difference between the mean ADCs of the reference organs (n = 7, 1.54 ± 0.24) and the malignant (n = 25, 1.18 ± 0.70) lesions. Conclusions DWIBS can be used for the detection of malignant tumors or benign tumors; however, it may be difficult to differentiate between benign and malignant lesions by ADC.     

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

Purpose

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases.

Methods

Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85 ± 13 min after ¹⁸F-FDG injection of 403 ± 45 MBq) and then (125 ± 19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison.

Results

Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64 ± 0.70; in-phase, 1.29 ± 1.01; opposed-phase, 1.29 ± 1.15; water-weighted, 1.71 ± 1.07; fat weighted, 0.56 ± 1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63 ± 1.62; SUVmax, 4.30 ± 2.88) and contrast-enhanced PET/CT (SUVmean, 3.88 ± 2.30; SUVmax, 6.53 ± 4.04) in PET-positive lesions (SUVmean, ρ = 0.93; SUVmax, ρ = 0.95), although hybrid PET/MR presented a decrease of SUVs compared with contrast-enhanced PET/CT (mean reduction; SUVmean, 32.44 ± 15.64 %; SUVmax, 35.16 ± 12.59 %).

Conclusions

Despite different attenuation correction approaches, the SUV of PET-positive lesions correlated well between hybrid PET/MR and contrast-enhanced PET/CT. However Dixon MR images acquired for attenuation correction were insufficient to provide anatomic information of PET images because of low spatial resolution. Thus, additional MR sequence with fast and higher resolution may be necessary for anatomic information.     

PET/MRI在肿瘤研究中的新进展

PET/MRI成像整合了PET提供的人体生理代谢、分子信息和MRI提供的功能、解剖形态信息,在肿瘤诊断、评估肿瘤生物学行为(包括分期、分级、浸润深度、远处转移)、评价治疗疗效及预后方面具有较高的准确性、敏感性、特异性,实现了PET及MR成像设备的优势互补。就PET/MRI在肿瘤中的应用现状及其发展前景进行回顾和展望。     

CT, MR, US, 18F-FDG PET/CT, and their combined use for the assessment of cervical lymph node metastases in squamous cell carcinoma of the head and neck

The purpose of this retrospective study was to compare the diagnostic value of four different imaging methods—computed tomography (CT), magnetic resonance (MR) imaging, ultrasonography (US), and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT—and their combined use for preoperative detection of cervical nodal metastases in head and neck squamous cell carcinoma (SCC). Sixty-seven patients (58 men and 9 women; mean age, 60.1 years) with head and neck SCCs underwent CT, MR, US, and PET/CT before surgery. First, each study was reviewed separately for the presence of nodal metastases. Then, the value of combined images was assessed based on a confidence rating score for each modality assigned by observers. These results were verified, on a level-by-level basis, with histopathologic findings. Histopathologic examination revealed nodal metastases in 74 of 402 nodal levels. The sensitivity, specificity, and accuracy were 77.0%, 99.4%, and 95.3% for CT and MR; 78.4%, 98.5%, and 94.8% for US; and 81.1%, 98.2%, and 95.0% for PET/CT, respectively. The comparison of these modalities showed no statistically significant difference among them (p > 0.05). The combination of CT, MR, US, and PET/CT improved sensitivity (86.5%), without loss of specificity (99.4%) and accuracy (97.0%), although the difference failed to reach statistical significance.     

Comparison of the utility of whole-body MRI with and without contrast-enhanced Quick 3D and double RF fat suppression techniques,conventional whole-body MRI,PET/CT and conventional examination for assessment of recurrence in NSCLC patients

Purpose

The purpose of this study was to compare diagnostic capabilities for assessment of recurrence in non-small cell lung cancer (NSCLC) patients by contrast-enhanced whole-body MRI (CE-WB-MRI) with and without CE-Quick 3D and double RF fat suppression technique (DFS), FDG-PET/CT and conventional radiological examinations.

Materials and methods

A total of 134 pathologically proven and completely resected NSCLC patients (78 males, 56 females; mean age: 72 years) underwent FDG-PET/CT, CE-WB-MRI with and without Quick 3D and DFS at 3 T as well as conventional radiological examinations. The probability of recurrence was assessed with a 5-point scoring system on a per-patient basis, and final diagnosis was made by consensus between two readers. The capability for overall recurrence assessment by all the methods was compared by means of ROC analysis and their sensitivity, specificity and accuracy by means of McNemar's test.

Results

Although areas under the curve did not show any significant differences, specificity (100%) and accuracy (95.5%) of CE-WB-MRI with CE-Quick 3D and DFS were significantly higher than those of FDG-PET/CT (specificity: 93.6%, p = 0.02; accuracy: 89.6%, p = 0.01) and conventional radiological examinations (specificity: 92.7%, p = 0.01; accuracy: 91.0%, p = 0.03). In addition, specificity of CE-WB-MRI without CE-Quick 3D and DFS (100%) was significantly higher than that of FDG-PET/CT (p = 0.02) and conventional radiological examinations (p = 0.01).

Conclusion

Specificity and accuracy of CE-WB-MRI with CE-Quick 3D and DFS for assessment of recurrence in NSCLC patients are at least as high as, or higher than those of others.     

18F-FDG PET/CT and PET/MRI fusion imaging for neuroendocrine carcinoma of the tongue: A case report

Neuroendocrine carcinoma (NEC) involving the tongue is a rare and aggressive disease that is more common in middle-aged and elderly males. We report a case of a 56-year-old male who presented to our hospital with sore throat and was found to have a mass in the left root of the tongue. ¹⁸F-FDG PET/CT revealed intense FDG uptake in the mass of the tongue base, as well as different uptake of FDG in the mid-posterior mediastinal mass, right adrenal gland, and enlarged lymph nodes in the neck and mediastinum. Gadolinium-enhanced MRI clearly showed the extent of the tongue lesion, additionally suggesting the presence of brain metastases. ¹⁸F-FDG PET/MRI fusion images of the neck were obtained on the workstation, which may have a higher diagnostic value for tongue NEC. The patient underwent a biopsy of the mass in the left root of the tongue and was pathologically diagnosed with NEC. Whole-body ¹⁸F-FDG PET/CT and regional PET/MRI fusion images have complementary roles in the diagnosis of tongue NEC, and the former is mainly applied to determine the clinical stage of the disease and to guide treatment.     

Cerebral fat embolism studied with MRI and SPECT

Summary In a patient with fat embolism to the brain CT showed no abnormality. MRI performed after recovery from coma, when the patient had aphasia and quadriparesis, demonstrated multiple high signal abnormalities in the white matter on both T1- and T2-weighted images. HMPAO-SPECT showed left-sided hypoperfusion which resolved in parallel with clinical improvement 1 month later.