INTRODUCTION:Cerebral punctate and curvilinear gadolinium enhancements (PCGE) correspond to opacification of small vessel lumen or its perivascular areas in case of blood-brain barrier (BBB) disruption. We will discuss the possible causes of intra-parenchymal central nervous system PCGE.METHODS:Our review is based on French database including patients presenting with central nervous system PCGE and literature search using PubMed database with the following keywords: punctate enhancement, linear enhancement, and curvilinear enhancement. Disorders which displayed linear leptomeningeal or periventricular enhancements without intra-parenchymal PCGE are excluded of this review.RESULTS:Among our 39 patients with PCGE, 16 different diagnoses were established. After combining our PCGE causes with those described in the literature, we propose a practical approach. Besides physiologic post-contrast enhancement of small vessels, three pathologic conditions may exhibit PCGE: (1) small collateral artery network seen in Moyamoya syndrome, (2) small veins congestions related to developmental or acquired venous outflow disturbance, and (3) disorders causing small vessels BBB disruption indicated by T2 and FLAIR hyperintensities in the corresponding areas of PCGE. Disruption of the BBB could be caused by a direct injury of the endothelial cell, as in posterior reversible encephalopathy syndrome, Susac syndrome, and radiochemotherapy-induced injuries, or by an angiocentric cellular infiltrate, as in inflammatory disorders, demyelinating diseases, host immune responses fighting against infections, prelymphoma states, lymphoma, and in CLIPPERS.CONCLUSION:PCGE may conceal several causes, including physiological and pathological conditions. Nevertheless, a practical approach could improve its management and limit the indications of brain biopsy to very specific situations

INTRODUCTION:Convex spherical anamorphosis is a barrel distortion that consists of the application of a plane surface on a convex hemisphere. Applied in vascular imaging of brain arteriovenous malformations (bAVMs), this deformation may help to 'spread' the nidus and surrounding vessels (arteries/veins) and thus to differentiate the different components of bAVMs more accurately.METHODS:The imaging data from 15 patients (8 male, 7 female; 14 supratentorial bAVMs, 1 infratentorial) were used to test the algorithm. The algorithm was applied to three-dimensional rotational angiography (3D-RA) volume rendering reconstructions in anteroposterior, lateral and oblique views and compared with regular 3D-RA and DSA. Arterial feeder and draining vein count and quality visualization of the main draining vein and intranidal aneurysms were compared between the three imaging techniques.RESULTS:Anamorphosis was able to depict more arterial feeders than 3D-RA alone (p=0.027). There was no statistically significant difference between 6 f/s DSA and anamorphosis for arterial feeder count. No difference was observed in draining vein count between the three imaging modalities. Visualization of the precise origin of the main draining vein was considered to be good in 67% of the cases with anamorphosis versus 47% and 33% for 6 f/s DSA and 3D-RA alone, respectively. Intranidal aneurysms were accurately depicted by anamorphosis (2 cases), whereas 6 f/s DSA and 3D-RA showed doubtful images in one and two additional cases, respectively, which were finally confirmed as focal venous ectasias on supraselective injection.CONCLUSIONS:Anamorphosis can help to visualize more precisely the main draining vein origin of the bAVM and depict more accurately intranidal aneurysms.

BACKGROUND:Progressive multifocal leukoencephalopathy (PML) is an opportunistic demyelinating encephalopathy related to JC virus. Its characteristics on conventional brain MRI are well known and are important for the diagnosis.OBJECTIVE:To analyze SWI hypointensities recently described in U-fibers and cortex adjacent to the white matter lesions of PML.METHODS:Prospective study including four patients with an history of definite diagnosis of PML. Clinical data were collected retrospectively. Brain MRI exams were done on a 3T magnet, including FLAIR, T2 GRE sequences and SWI.RESULTS:Four males were included (mean age: 47 years, mean PML duration: 24.2 months). Immunosuppression was related to AIDS (n=2), natalizumab for multiple sclerosis (n=1), B-cell lymphoma treated by chemotherapeutic agents and rituximab (n=1). All patients had SWI hypointensities in cortex and/or U-fibers adjacent to the white matter lesions. QSM always suggested a paramagnetic effect.CONCLUSION:SWI and T2 GRE hypointensities in cortex and U-fibers adjacent to the white matter lesions seem highly prevalent in PML, irrespective of the delay between PML onset and the MRI. QSM data suggest a paramagnetic effect.