MR扩散加权成像对Creutzfeldt-Jakob病的诊断意义

目的评价MR扩散加权像(DWI)对Creutzfeldt-Jakob病(CJD)的诊断价值。方法8例散发性CJD(4例确诊，3例临床很可能，1例临床可能)，比较其常规MRI及DWI检查结果。结果T1WI及LWI除4例显示脑萎缩外，未见异常信号；而8例DWI均异常，其中2例为单纯大脑皮层高信号改变，6例为大脑皮层合并尾状核、壳核高信号改变，5例呈对称性，3例呈非对称性；1例液体衰减反转恢复(FLAIR)序列成像显示大脑皮层呈稍高信号，但不如DWI明显。结论DWI显示的大脑皮层和(或)纹状体的高信号改变是CJD的特征之一，其诊断价值明显优于常规MRI，是早期诊断CJD的重要方法。     

Creutzfeldt-Jakob disease: focal symmetrical cortical involvement demonstrated by MR imaging.

The authors present two biopsy-proved cases of Creutzfeldt-Jakob disease. MR appears to be more sensitive than CT in detecting pathologic changes; signal abnormalities, when found, are predominantly within gray matter and may involve only peripheral cortex.     

MR imaging of familial Creutzfeldt-Jakob disease: a blinded and controlled study

BACKGROUND AND PURPOSE: The E200K mutation of the PRNP (prion protein) gene is the most common cause of familial Creutzfeldt-Jakob disease (fCJD), which has imaging and clinical features that are similar to the sporadic form. The purpose of this study was to conduct a controlled and blinded evaluation of the sensitivity and specificity of MR imaging in this unique population.MATERIALS AND METHODS: We compared the MR imaging characteristics of 15 early stage familial CJD patients (age, 60 ± 7 years) with a group of 22 healthy subjects from the same families (age, 61 ± 8 years). MR imaging included diffusion-weighted imaging (DWI), T2-weighted fast spin-echo imaging, and a fluid-attenuated inversion recovery (FLAIR) sequence. The scans were rated for abnormalities by an experienced neuroradiologist blind to diagnosis, group assignment, age, and sex.RESULTS: Thirteen of 15 fCJD subjects had abnormal MR imaging. FLAIR signal intensity abnormality in the caudate or putamen nuclei demonstrated a sensitivity of 87% and specificity of 91%. DWI abnormality in the caudate nucleus showed a sensitivity of 73% and a specificity of 100%. Abnormalities in the thalamus (6 patients), cingulate gyrus (6 patients), frontal lobes (4 patients), and occipital lobes (3 patients) were best detected with DWI. No signal intensity abnormalities were demonstrated in the cerebellum. T2-weighted and T1-weighted sequences were uninformative.CONCLUSIONS: FLAIR and DWI abnormalities in the caudate nucleus and putamen offer the best sensitivity and specificity for diagnosing fCJD. Our findings support recent recommendations that MR imaging should be added to the diagnostic evaluation of CJD.

Creutzfeldt-Jakob disease (CJD) is the most common human prion disease. It is a rare neurodegenerative disorder that is progressive and invariably fatal, with nearly 90% of patients dying within 1 year of diagnosis.¹ CJD occurs in approximately 1 person per 1 million people per year worldwide.¹ The most common form is sporadic CJD (sCJD), which occurs randomly without a known risk factor and accounts for 85%-90% of cases. Familial or hereditary CJD (fCJD), seen in 5%-10% of cases, is caused by mutations in the gene that controls formation of the normal prion protein on chromosome 20.¹ The most common pathogenic mutation is the E200K mutation. The risk of fCJD is transmitted in an autosomal dominant inheritance pattern, with nearly 100% penetrance.²The imaging findings in sCJD typically consist of cortical atrophy and hyperintensities in the basal ganglia, thalamus, and cortex on fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI).^3–13 fCJD has imaging findings and neuropathology that are, in general, similar to the most common forms of sCJD; however, most imaging studies on fCJD consist primarily of case reports or studies focused on sCJD that combine a few fCJD patients into a single CJD patient sample.^8,14–22 fCJD studies are limited not only by small sample sizes but also by nonstandardized imaging protocols and clinical and pathophysiologic heterogeneity. The complex interactions with disease duration and cognitive and neurologic severity have also made it difficult to interpret studies, especially because the sample sizes are small.²³To address the difficulties of clinical research in this area, we initiated a study of fCJD occurring among Libyan Jews living in Israel that is caused by familial transmission of the E200K mutation.^24–26 In a preliminary report, it was demonstrated that 4 patients with fCJD due to the E200K mutation had gray matter atrophy and decreased apparent diffusion coefficient (ADC) in the basal ganglia. Signal intensity hyperintensities were seen in the basal ganglia and thalamus with FLAIR and DWI.²⁷ The sample size in that study was insufficient to calculate sensitivity and specificity. Here we describe a rigorously blinded and controlled evaluation of MR imaging findings in a larger number of fCJD patients.     

Serial MR imaging in Creutzfeldt-Jakob disease

Summary Serial magnetic resonance (MR) imagings of two autopsied patients with Creutzfeldt-Jakob disease (CJD) are presented. Both patients showed a dramatic progression of brain atrophy. The initial MR imagings were, however, interpreted as normal except for localized mild cortical atrophy in one patient. When a normal MR image is obtained in a demented middle-aged or aged patient, CJD may still need to be ruled out: follow up MR imaging may be useful.     

Isolated cortical signal increase on MR imaging as a frequent lesion pattern in sporadic Creutzfeldt-Jakob disease

BACKGROUND AND PURPOSE: Hyperintense basal ganglia on MR imaging support the diagnosis of sporadic Creutzfeldt-Jakob disease (CJD). Our aim was to study the frequency of patients with sporadic CJD presenting with and without characteristic basal ganglia lesions on MR imaging and to examine the corresponding patient characteristics.MATERIALS AND METHODS: Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted images (DWI) of 55 patients with CJD were assessed for signal-intensity increase (FLAIR) or restricted diffusion (DWI) in 7 cortex regions and the basal ganglia, thalamus, and cerebellum. Patient characteristics as well as electroencephalography, CSF, and codon 129 genotype of the prion protein gene (PRNP) were correlated with the most frequent MR imaging lesion patterns.RESULTS: Two major lesion patterns were identified by DWI: cortex and basal ganglia involvement (two thirds) and isolated cortex involvement (one third). In the latter patient group, the cortex involvement was widespread (at least 3 regions affected in 89% on DWI) and usually included the frontal and parietal lobes (78%). The length of the disease course was significantly prolonged (median, 12 versus 5 months). No significant differences were observed concerning electroencephalography and CSF findings and codon 129 genotype distributions. Of 4 patients with normal MR imaging findings, the CSF was positive for the 14-3-3 protein in 3.CONCLUSION: A high number of patients with CJD present without basal ganglia lesions on MR imaging. Isolated cortex involvement on DWI and FLAIR should lead to suggestion of CJD, even if the disease course is only slowly progressive. Additional 14-3-3 protein analysis in the CSF may support the CJD diagnosis.

Sporadic Creutzfeldt-Jakob disease (CJD) is a rare and fatal disease caused by the accumulation of abnormal/pathologic prion protein (PrP^Sc; Sc indicates scrapie) in the human brain. The classic disease type is characterized by rapidly progressive dementia, ataxia, abnormal muscle tone, and myoclonus. It leads to a state of akinetic mutism and death after a median disease duration of 6 months.¹ The definite CJD diagnosis relies on the finding of PrP^Sc in the brain tissue, together with astrocytic gliosis, nerve cell loss, and spongiform degeneration as the typical neuropathologic changes.^2,3During one''s lifetime, MR imaging hyperintensity of the basal ganglia on T2-weighted (T2WI), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) is increasingly used to support the CJD diagnosis, next to positive CSF (14-3-3 protein) and electroencephalography (EEG) findings of periodic sharp-wave complexes (PSWCs). Although the origin of the signal-intensity changes is still not fully understood, hyperintensity on T2WI and FLAIR has been thought to be caused by gliosis, whereas abnormalities on DWI are most likely derived from spongiform changes.^4–6 DWI was shown to be the most sensitive sequence in the detection of brain lesions, particularly in the neocortex.^7–10 Isolated cortex involvement was also found.^9,11Although abnormal MR imaging findings in CJD have been studied in detail with respect to their location, few attempts have been made to define the most frequently occurring patterns of hyperintensity in a spectrum of patients. Six disease phenotypes (MM1, MM2, MV1, MV2, VV1, and VV2) defined by the codon 129 genotype (MM, MV, VV) of the prion protein gene (PRNP) and pathologic isotype of the PrP^Sc type 1 or 2 have been recently described with distinctive neuropathologic features and various clinical and diagnostic findings.^1–3,12 On MR imaging, predominant cortical (VV1)¹³ or subcortical involvement (MV2 and VV2)^14,15 or no abnormalities (MM2)^16,17 were found in smaller case series.To date, to our knowledge, the overall distribution of MR imaging abnormalities has not been studied in a larger spectrum of patients with CJD, and it is unclear whether there are clinical correlates corresponding to specific MR imaging lesion patterns. The proportion of patients presenting without basal ganglia abnormalities is unknown.We defined the most frequent MR imaging lesion patterns and corresponding clinical characteristics in a CJD patient collective by using highly sensitive MR images, and we considered a possible influence of the codon 129 genotype of the PRNP. We particularly focused on patients lacking basal ganglia abnormalities on MR imaging and suggested criteria that might support the early CJD diagnosis in these patients.     

Emerging patterns of diffusion-weighted MR imaging in Creutzfeldt-Jakob disease: case report and review of the literature

We report the use of diffusion-weighted MR imaging in the early diagnosis and monitoring of the progression of a histopathologically proved case of sporadic Creutzfeldt-Jakob disease. Ribbon-like areas of hyperintensity in the cerebral cortex on diffusion-weighted images corresponded to the localization of periodic sharp-wave complexes on the electroencephalogram.     

Creutzfeldt-Jakob disease: comparative analysis of MR imaging sequences

BACKGROUND AND PURPOSE: MR imaging has played an increasingly important role in the diagnosis of Creutzfeldt-Jakob disease (CJD) since basal ganglia abnormalities on T2-weighted images have been described; thus, the aim of our study was to compare the value of different MR images in the diagnosis of CJD. METHODS: One hundred fifty-seven patients with CJD underwent MR imaging examinations. Ninety-two patients were neuropathologically confirmed, and 65 were clinically classified as having CJD through the CJD Surveillance Unit (probability of 95%). There was no standardized MR imaging protocol; thus, the examinations included 143 T2-weighted, 43 proton attenuation (PD)-weighted, 84 fluid-attenuated inversion recovery (FLAIR), and 44 diffusion-weighted images (DWI). The MR images were reviewed for pathologic changes of the basal ganglia, thalamus, and cerebral cortex. RESULTS: Cortical abnormalities were present in 70 patients (45%) and were visible in 80% (35/44) of all available DWI examinations. The basal ganglia were affected in 94 patients (60%), in particular in the caudate nucleus; the most sensitive sequences were DWI (64%) and PD-weighted (63%). A thalamic involvement was more frequently diagnosed on PD-weighted images (19%) and DWI (14%) than on FLAIR or T2-weighted images. CONCLUSION: PD-weighted images and DWI showed better results in the diagnosis of signal intensity changes in the basal ganglia compared with T2-weighted or FLAIR images; however, in the diagnosis of cortical changes, DWI was clearly superior. Our data suggest that DWI is the most sensitive MR imaging technique in the diagnosis of CJD.     

Cerebral MR and CT imaging in Creutzfeldt-Jakob disease

Magnetic resonance (MR) imaging and CT of three patients with Creutzfeldt-Jakob disease (CJD) showed bilateral cortical atrophy and no apparent white matter changes. Serial examinations revealed the progressive nature of the atrophy, findings compatible with the patients' clinical deterioration. At autopsy some white matter abnormalities were detected in one patient 6 months after MR imaging. The available data suggest that the white matter abnormalities, if present, develop during the final stage of CJD.     

Conspicuity and evolution of lesions in Creutzfeldt-Jakob disease at diffusion-weighted imaging

BACKGROUND AND PURPOSE: Diffusion-weighted imaging can disclose distinct hyperintense lesions in Creutzfeldt-Jakob disease (CJD). However, these findings and chronologic changes of CJD at diffusion-weighted imaging have not been fully investigated. Our purpose was to assess the diagnostic value of diffusion-weighted imaging in depicting CJD-related lesions and in tracking the evolution of these lesions. We also compared the sensitivity of diffusion-weighted imaging in depicting CJD-related lesions to that of fluid-attenuated inversion recovery (FLAIR) imaging. METHODS: We reviewed findings in 13 patients with a diagnosis of CJD who underwent MR imaging, including diffusion-weighted imaging. Nine patients were initially examined within 4 months of onset of symptoms (early stage), and eight were examined 4 months or later (late stage). We evaluated four items: 1) distribution of lesions at diffusion-weighted imaging, 2) conspicuity of lesions at diffusion-weighted imaging and FLAIR imaging, 3) chronologic changes in lesions at diffusion-weighted imaging, and 4) chronologic changes in lesions revealed by apparent diffusion coefficient (ADC) maps. RESULTS: Patients had striatal lesions or cerebral cortical lesions or both. The thalamus was involved in only one patient, and the globus pallidus was spared in all patients. The sensitivity of diffusion-weighted imaging in depicting lesions was superior or at least equal to that of FLAIR imaging. Hyperintense lesions at diffusion-weighted imaging changed in extent and intensity over time. Unlike infarction, lesional ADC decreased for 2 weeks or longer. CONCLUSION: The progressively hyperintense changes in the striata and cerebral cortices at diffusion-weighted imaging are considered characteristic of CJD. Diffusion-weighted imaging may be useful for the early diagnosis of CJD.     

FDG-PET and diffusion-weighted MR imaging appearance in retroperitoneal Castleman's disease: a case report

Castleman's disease is a rare lymphoid neoplasm that is characterized by the proliferation of lymphoid tissue. A case of young woman having the plasma cell type of retroperitoneal Castleman's disease is reported, and radiological findings of the condition are discussed with a review of the radiological literature.     

Serial diffusion-weighted MRI of Creutzfeldt-Jakob disease

OBJECTIVE: The objective of our study was to evaluate the clinical usefulness of MRI findings, including diffusion-weighted imaging, in relation to the clinical signs and symptoms of Creutzfeldt-Jakob disease (CJD). MATERIALS AND METHODS: We reviewed nine cases of CJD in which MRI was performed from the early to terminal phase of the disease. MRI findings were correlated before (early phase) and after (intermediate phase) the onset of the characteristic clinical findings of myoclonus and periodic synchronous discharges on electroencephalograms. The chronologic changes in imaging findings were followed from the akinetic mutism to the terminal phase of the disease (terminal phase). T2-weighted images had been obtained in all the patients, and diffusion-weighted images and FLAIR images had been obtained in six patients. We evaluated the images for the presence and location of abnormal signal intensities. RESULTS: During the early phase, the T2-weighted images showed no abnormal findings. The diffusion-weighted images, however, revealed abnormal high signal intensities in the cortex in all patients and in the basal ganglia in five patients. In two cases, there were abnormal signals on FLAIR images that corresponded to diffusion-weighted imaging abnormalities. During the intermediate phase, the area of the high signal intensities on the diffusion-weighted images had expanded and progressive cerebral atrophy had become apparent. During the terminal phase, abnormal high signal intensities in the cerebral cortex and basal ganglia on the diffusion-weighted images in one patient disappeared. CONCLUSION: Diffusion-weighted imaging is extremely useful in detecting CJD during the very early phase-even before the onset of characteristic clinical findings.     

Creutzfeldt-Jakob disease: serial changes on diffusion-weighted MRI

We present serial changes on diffusion-weighted MRI (DWI) in a patient with Creutzfeldt-Jakob disease (CJD). DWI revealed serial changes of abnormal hyperintense lesions that had become more extensive and conspicuous with progression of neurologic findings, more sensitively than conventional MRI. In the late stage, disappearance of abnormal hyperintense lesions on DWI was observed. DWI proved to be particularly useful for monitoring the progression of CJD.     

磁共振超高b值弥散序列指导前列腺穿刺的初步研究

目的探讨MR超高b值弥散序列指导前列腺穿刺的临床意义。方法前列腺穿刺病理证实患者共计48例,其中前列腺癌15例,前列腺增生33例。所有患者行MR常规扫描及弥散序列扫描,b=800,1500。以穿刺所得病理结果为金标准,分别观察前列腺癌及前列腺增生的常规b值及超高b值弥散图像特点。同时评价常规b值,超高b值及两组联合的诊断灵敏度、特异度、阳性预测值、阴性预测值。结果常规b值,超高b值及两组联合的诊断灵敏度分别为79.17%,62.5%,91.67%;特异度分别为75.61%,95.12%,95.12%;阳性预测分别为60%,88.24%,91.67%;阴性预测值分别为86.11%,81.25%,95.12%。前列腺癌在超高b值图像上呈高信号,具有明显的特征,在常规b值图像上前列腺癌及前列腺增生均可呈等信号或高信号影。在诊断效能方面,超高b值联合常规b值对比2种单独引导具有明显优越性。结论趟高b值弥散序列有助于前列腺癌的诊断,尤其在联合常规b值的情况下,明显提高诊断效能。     

脑白质疏松症的MR扩散加权成像及波谱研究

目的通过MR扩散加权成像(DWI)及MR波谱(MRS)分析脑白质疏松症(LA)的表观扩散值(ADC)和不同代谢产物比值的变化,探讨LA中脑白质缺血过程中出现的病理、生化改变与MR功能成像改变之间的关系。方法30例经常规MRI检查诊断为LA患者,及30例年龄相匹配的正常脑白质表现的患者作为对照组,进行DWI检查,分析病变不同区域ADC值的变化,同时对LA患者进行MRS分析N-乙酰天门冬氨酸(NAA)/肌酸(Cr)、胆碱复合物(Cho)/肌酸(Cr)比值的变化,比较不同位置和不同程度病变在ADC值和代谢变化中的差异。结果LA患者病灶区(双侧侧脑室枕角、体部旁脑白质)ADC值升高与对照组差异有显著的统计学意义(P<0.01),相应病灶区的NAA/Cr均值明显降低,Cho/Cr均值升高,与正常白质比较差异有显著统计学意义(P<0.01),而枕角的NAA/Cr均值低于体部,差异有显著统计学意义(P<0.01)。结论磁共振功能成像能够反映脑白质疏松症发展中的微观结构变化和局部代谢的异常。     

Interhemispheric asymmetry of brain diffusivity in normal individuals: a diffusion-weighted MR imaging study

BACKGROUND AND PURPOSE: Previous neuroimaging studies have suggested asymmetries in brain diffusivity may exist. The purpose of this study was to assess whether water diffusivity in deep gray matter structures shown by diffusion-weighted (DW) imaging differs between the right and left cerebral hemispheres in normal individuals. METHODS: Brain MR imaging was obtained in 23 healthy volunteers. A multisection image without diffusion weighting, and images with weighting applied in the read, phase, and section directions with a b-factor of 1000 s/mm(2) were collected. Diffusivity was computed separately in each direction, and the results were averaged to form mean diffusivity maps. Quantitative diffusivity values were obtained from the globus pallidus, putamen, caudate, thalamus, white matter, and CSF by using a standardized region of interest template. Interhemispheric differences were assessed by using a paired sample t test. RESULTS: Mean diffusivity was higher in the: left (mean +/- SD: 0.689 x 10(-3)+/- 0.069 x 10(-3)mm(2)/s) versus right (0.642 x 10(-3)+/- 0.071 x 10(-3)mm(2)/s) caudate (% difference, P value: 7.0%, P = .001); right (0.745 x 10(-3)+/- 0.053 x 10(-3)mm(2)/s) versus left (0.706 x 10(-3)+/- 0.050 x 10(-3)mm(2)/s) globus pallidus (5.2%, P < .001); left (0.720 x 10(-3)+/- 0.059 x 10(-3)mm(2)/s) versus right (0.674 x 10(-3)+/- 0.052 x 10(-3)mm(2)/s) putamen (6.4%, P < .001); right (0.750 x 10(-3)+/- 0.040 x 10(-3)mm(2)/s) versus left (0.716 x 10(-3)+/- 0.031 x 10(-3)mm(2)/s) thalamus (4.5%, P < .001). No significant right versus left difference was seen in the CSF (P = .291), anterior frontal white matter (P = .834), or centrum semiovale (P = .320). CONCLUSION: Gray matter diffusivity may differ between hemispheres of the brain in healthy individuals. Analysis of deep gray matter lesions requires caution, as statistically significant interhemispheric differences may not always be indicative of disease.     

CT and MRI in iatrogenic and sporadic Creutzfeldt-Jakob disease: as far as imaging perceives

Creutzfeldt-Jakob Disease (CJD), an invariably fatal dementing illness, affects patients in middle and old age (sporadic form). However, the association of CJD with certain treatments (iatrogenic form) has been described in younger patients. The clinical onset of the two forms seems to differ; in the iatrogenic form a high frequency of the ataxic CJD variant has been reported. Nowadays, a definitive diagnosis of CJD is exclusively histological. We present five cases of CJD, one sporadic and the others iatrogenic, following dura mater grafts and analyse their CT and MRI features. CT typically demonstrates brain atrophy, generally progressive, but in sporadic CJD midfield MRI also showed abnormal signal, with predominant deep grey matter involvement. The use of narrow windows with proton-density sequences may reveal subtle cortical signal abnormalities not clearly visible with conventional windows. The early demonstration of these changes, in the appropriate clinical context, may suggest CJD and this supports the use of mid- or high magnetic fields in the diagnosis of CJD and other forms of dementia. In our cases of iatrogenic CJD, low-field MRI did not reveal more than the progressive atrophy displayed by CT, and raises the question on the one hand of possible differences, based on imaging, from the sporadic form, and on the other of the lack of sensitivity of low-field magnets to signal changes in CJD.Presented in part at the 6th annual meeting of the Sociedad Ibero-Latinoamericana de Neuroradiología Diagnóstica y Terapéutica (SILAN) Madrid, June 1994