T1 post-gad PDW T2

Diagnosis: Pontine infarct

Regarding infarcts of the posterior circulation, the pons is the most commonly infarcted region. The most common etiology of posterior circulation infarct is stenosis or occlusion of the basilar artery. Other large arterial stenoses may be seen. Another frequent cause of posterior circulation infarct is cardiac embolus. The paramedian appearance of pontine infarct is due to occlusion of the perforators of the basilar artery which supply each side of the pons in a parallel fashion. Hence the unilateral, geographic appearance of typical pontine infarcts. Enhancement pattern of stroke is variable but gadolinium enhancement may persist for a few months after the infarct.

The other entities listed in the differential are much less likely. Demyelinating disease may involve the pons; however, the laterality of this lesion would be extremely atypical. Likewise, neoplasm is highly unlikely given the clinical history and the lack of mass effect with no significant enhancement. Related Cases

Miyashita K, Naritomi H, Sawada T, Nakamura M, Kuriyama Y, Ogawa M, Imakita S. Identification of recent lacunar lesions in cases of multiple small infarctions by magnetic resonance imaging. Stroke, Jul 1988; 19(&):p834-9.

Bogousslavsky J, Regli F, Maeder P, Meuli R, Nader J. The etiology of posterior circulation infarcts: a prospective study using magnetic resonance imaging and magnetic resonance angiography. Neurology, Aug 1993; 43(8):p1528-33.

Uchino A, Onomura K, Ohno M. MR imaging of brainstem infarction. Rinsho Hoshasen, Mar 1989; 34(3):p313-6.















































Astrocytoma Posterior fossa infarcts Multiple sclerosis