Neuroradiology of human prion diseases, diagnosis and differential diagnosis

Abstract

Human transmissible spongiform encephalopathies (TSEs), or prion diseases, are invariably fatal conditions associated with a range of clinical presentations. TSEs are classified as sporadic [e.g. sporadic Creutzfeldt-Jakob disease (sCJD), which is the most frequent form], genetic (e.g. Gerstmann-Straussler-Scheinker disease, fatal familial insomnia, and inherited CJD), and acquired or infectious (e.g. Kuru, iatrogenic CJD, and variant CJD). In the past, brain imaging played a supporting role in the diagnosis of TSEs, whereas nowadays magnetic resonance imaging (MRI) plays such a prominent role that MRI findings have been included in the diagnostic criteria for sCJD. Currently, MRI is required for all patients with a clinical suspicion of TSEs. Thus, MRI semeiotics of TSEs should become part of the cultural baggage of any radiologist. The purposes of this update on the neuroradiology of CJD are to (i) review the pathophysiology and clinical presentation of TSEs, (ii) describe both typical and atypical MRI findings of CJD, and (iii) illustrate diseases mimicking CJD, underlining the MRI key findings useful in the differential diagnosis.

Subtype Diagnosis of Sporadic Creutzfeldt–Jakob Disease with Diffusion Magnetic Resonance Imaging

“…Advances in diffusion‐weighted imaging (DWI) technology have significantly upgraded the diagnostic capabilities of MRI 25 . Along with amendments of its criteria 26,27 and the increasing experience acquired by neuroradiologists, diffusion MRI has become highly reliable in the diagnosis of CJD, despite the rarity of this condition, 21,28,29 reaching sensitivity and specificity values greater than 90% 1,21,27,30–32 . Moreover, MRI plays a pivotal role as an early diagnostic test in patients who present with rapidly evolving signs of cognitive dysfunction, and it can strongly suggest sCJD even before a physician seriously considers this diagnosis 25 .…”

Prion Disease

“…18,19 A helpful diagnostic feature commonly seen in sCJD is the MRI finding of abnormal restricted diffusion in the cortex, caudate, and/or putamen and abnormal FLAIR hyperintensities in the cortical ribbon. [20][21][22] MRI has variable sensitivity (92-96%) and specificity (93-94%) for the diagnosis of sCJD (►Fig. 2).…”

Neuroimaging in emergency: a review of possible role of pineal gland disease

“…Imaging findings: pineocytomas appear as small (usually less than 3 cm), iso-hyperdense, well-circumscribed d e m a r c a t e d l e s i o n s a t C T; u n l i k e G C Ts , p i n e a l parenchymal tumors tend to expand and displace the normal pineal calcifications toward the periphery. MRI evaluation can better define internal tissue characteristics and vascularization after gadolinium administration (60)(61)(62)(63)(64). At MRI, pineocytomas are well-demarcated lesions, hypo-isointense on T1-weighted and hyperintense on T2-weighted sequences.…”