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

Abstract

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.

Fig 1.

Case 1. Sample case of predominant striatal lesions in the early stage. Images were obtained at 3 (A and B) and 5 (C and D) months from the onset of symptoms. A, FLAIR image shows changes, which are not as conspicuous as in B. B, Striata appear hyperintense at diffusion-weighted imaging. Note that the anterior portion of the bilateral putamina (arrows) appears more hyperintense than does the posterior portion at diffusion-weighted imaging. C and D, Severe atrophy is depicted in both cerebral cortices and the caudate nuclei heads at FLAIR imaging (C) and diffusion-weighted imaging (D). Note that the putamina are entirely involved in C as compared with their appearance in B. Hyperintensity in the heads of the caudate nuclei appears less prominent; this appearance is associated with their volume loss and the dilatation of the frontal horns.

Fig 2.

Case 3. Sample case in which cerebral cortices were involved mainly in the early stage. A and B, At 1 month from the onset of symptoms, FLAIR imaging (A) reveals only subtle changes, whereas diffusion-weighted imaging (B) reveals hyperintense lesions in the cerebral cortices with a faint left striatal lesion. Note that the left striatum is asymmetrically involved (the right striatum is spared), and the anterior portion of the left putamen appears hyperintense compared with the posterior portion (arrowhead in B). C, At 3 months from onset of symptoms, diffusion-weighted imaging reveals not only cortical lesions but also diffuse bilateral striatal lesions (arrowheads). Note that the left putaminal lesion spread posteriorly and entirely, as compared with its appearance in B.

Fig 3.

Case 13. Sample case in which a cortical lesion was apparent at diffusion-weighted imaging but not at FLAIR imaging. Images were obtained 2 months after onset of symptoms. A, FLAIR image barely depicts the lesions shown in B. B, Diffusion-weighted imaging reveals hyperintense cortical lesions in the medial aspects of bilateral frontal lobes.

Fig 4.

Case 10. Sample case in which FLAIR imaging is of little diagnostic value because of severe motion artifacts. Images were obtained 2.5 months after the onset of symptoms. A, Motion artifacts are so severe on the FLAIR image that it cannot provide diagnostic clues. B, Diffusion-weighted imaging, however, clearly reveals hyperintense lesions (arrows) in right temporo-occipital cortices and cingulate gyrus.

Fig 5.

Cases 3 (A and B) and 5 (C and D). Sample cases with chronologic changes in striatal lesions (arrow). A, At 1 month after the onset of symptoms, diffusion-weighted imaging reveals left striatal lesions. Note that the anterior portion of the left putamina appears more hyperintense than the posterior portion. B, At 3 months after the onset of symptoms, diffusion-weighted imaging reveals that the left putaminal lesions spread posteriorly and entirely, as compared with the findings in A. C, At 3 months after the onset of symptoms, diffusion-weighted imaging shows the right striatal lesion. Note that the high-signal-intensity change in the putamen is restricted to its anterior portion. D, At 5 months after the onset of symptoms, diffusion-weighted imaging shows that the putaminal lesion has spread in the posterior direction, as compared with the findings in C.

Fig 6.

Case 2. Sample case with chronologic changes in ADC in a striatal lesion. A and B, Diffusion-weighted imaging and corresponding ADC map, respectively. These images were obtained 7 months from the onset of symptoms. High signal intensity is present in the left striatum (A), and its lesional diffusivity is low (arrow in B). C and D, Diffusion-weighted imaging and corresponding ADC map, respectively. These images were obtained 8 months from the onset of symptoms. The lesion still has high signal intensity (C), and its ADC is still low (arrow in D).

Fig 7.

Case 2. Sample case with chronologic ADC changes in cerebral cortical lesions. A and B, Diffusion-weighted imaging and corresponding ADC map, respectively. These images were obtained 7 months after the onset of symptoms. The cerebral cortices are hyperintense (A), and lesional ADCs are low (arrows in B). C and D, Diffusion-weighted imaging and corresponding ADC map, respectively. These images were obtained 8 months after the onset of symptoms. The lesions are still hyperintense (C), and lesional ADCs are still low (arrows in D).

Fig 8.

Short-TI inversion recovery images. Dotted arrows in the left striatum show the supposed pathway of lesional distribution along the putaminocaudate gray matter bridges and nucleus accumbens septi. A, Coronal image shows the anatomic connections between the caudate head and the putamen. Solid arrow and arrowhead in the right cerebral hemisphere indicate the putaminocaudate gray matter bridges and the nucleus accumbens septi, respectively. B, Solid arrows in the left putamen on this axial image show the direction of lesional extension observed in our study.