MR screening of candidates for thrombolysis: How to identify stroke mimics?

DWI lesions reversal in posterior circulation stroke after reperfusion: Two illustrative cases and review of the literature

“…Herniations of brain parenchyma with surrounding CSF into the dural venous sinuses (DVS) or skull without apparent complete bone defects in the adjacent skull were recently described on MRI and CT [2][3][4]. The descriptions, possible etiologies, and clinical significances of this entity were determined differently in each of these reports.…”

“…The descriptions, possible etiologies, and clinical significances of this entity were determined differently in each of these reports. Chan et al [3] described a focal cerebellar hemisphere herniation into a giant arachnoid granulation located in occipital bone and right transverse sinus, which may have developed spontaneously or was induced by elevated intracranial pressure and cerebral edema due to prior head trauma. Coban et al [4] described a similar case of left temporal lobe parenchyma herniation surrounded with CSF into the left transverse sinus as an occult temporal lobe encephalocele.…”

“…Coban et al [4] coined the term ''occult encephalocele'' due to its distinguishing features from those of more common encephaloceles. Chan et al [3] described this entity as brain herniation into a giant arachnoid granulation. Battal and Castillo [2] described this entity as brain herniation with surrounding CSF into the DVS or calvarium.…”

“…In acute ischemic stroke, the diffusion-weighted imaging (DWI) lesion is commonly considered surrogate marker of irreversible core, and baseline infarct size seems to be a potent prognostic factor, either intravenous (IV) thrombolysis or an endovascular treatment [1][2][3]. Thus, accurate assessment of DWI lesion volume is crucial to establish cutoffs above which reperfusion may not be beneficial and may even be harmful.…”

Patient candidat à la thrombolyse : l’IRM est indispensable

“…7), lésions hyper-cellulaires (lymphome, médulloblas-tome) [19,20] ou hyperviscosité (abcès à pyogène) [21]. L'IRM permet également de redresser le diagnostic dans le cas de certains stroke mimics plus difficiles à détec-ter grâce à la conjugaison des différentes séquences : aura migraineuse ou oedème post-critique, par exemple [22,23]. hypersignal diffusion temporal gauche à prédominance corticale, ADC hétérogène diminué focalement, hypersignal FLAIR corticosous-cortical, avec un aspect tuméfié du lobe temporal gauche.…”