====== Perimesencephalic subarachnoid hemorrhage diagnosis ======

===== Perimesencephalic subarachnoid hemorrhage diagnosis Latest PubMed related articles =====
 

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===== CT =====


[[Perimesencephalic]] [[subarachnoid hemorrhage]]  has been defined as subarachnoid haemorrhage, which on [[CT]] within three days of [[symptom]] onset:

It is centred anteriorly to the [[pons]] and [[midbrain]]

May extend into the basal and [[suprasellar cistern]]s and into the proximal/basal Sylvian and [[interhemispheric fissure]]s
may settle as sediment in the [[occipital horn]]s of the [[lateral ventricle]]s but there is no overt intraventricular haemorrhage


===== CTA =====

Is recommended for PMSAH to investigate for possible aneurysmal cause. 

Undertaking a DSA after a negative CTA may not add any further diagnostic value in patients with PMSAH and may lead to net harm. This observation needs to be validated in a large-scale prospective multicenter study with complete case ascertainment and robust data on CTA and DSA complications
((Mohan M, Islim A, Dulhanty L, Parry-Jones A, Patel H. CT angiogram negative perimesencephalic subarachnoid hemorrhage: is a subsequent DSA necessary? A systematic review. J Neurointerv Surg. 2019 Dec;11(12):1216-1221. doi: 10.1136/neurintsurg-2019-015051. Epub 2019 Jul 4. PMID: 31273072.))

===== Cerebral angiography =====

[[Perimesencephalic subarachnoid hemorrhage cerebral angiography]]