Reproducibility of ABC/2 method to determine infarct volume and mismatch percentage with CT perfusion.

BACKGROUND: Our aim is to implement a simple, rapid, and reliable method using computed tomography perfusion imaging and clinical judgment to target patients for reperfusion therapy in the hyper-acute stroke setting. We introduce a novel formula (1-infarct volume [CBV]/penumbra volume [MTT] × 100%) to quantify mismatch percentage. METHODS: Twenty patients with anterior circulation strokes who underwent CT perfusion and received intravenous tissue plasminogen activator (IV tPA) were analyzed retrospectively. Nine blinded viewers determined volume of infarct and ischemic penumbra using the ABC/2 method and also the mismatch percentage. RESULTS: Interrater reliability using the volumetric formula (ABC/2) was very good (intraclass correlation [ICC] = .9440 and ICC = .8510) for hemodynamic parameters infarct (CBV) and penumbra (MTT). ICC coefficient using the mismatch formula (1-MTT/CBV × 100%) was good (ICC of .635). CONCLUSIONS: The ABC/2 method of volume estimation on CT perfusion is a reliable and efficient approach to determine infarct and penumbra volumes. The 1-CBV/MTT × 100% formula produces a mismatch percentage assisting providers in communicating the proportion of salvageable brain and guides therapy in the setting of patients with unclear time of onset with potentially salvageable tissue who can undergo mechanical retrieval or intraarterial thrombolytics.

Clinical reasoning: a 12-year-old boy with ascending weakness.

A 12-year-old boy presented with 3 weeks of calf pain, tripping, and progressive inability to walk. The onset was preceded by a sore throat 4 weeks prior, but no recent immunizations and no sick contacts. He began having problems "catching his toes" for 2 weeks. He had no visual complaints and no bowel or bladder incontinence. He had no recent travel and there were no heavy metal or solvent exposures. He had no prior medical history and he was on no prescription medications. Developmentally, he was on track and had just successfully completed fifth grade. However, he was reported to be behaviorally oppositional, especially regarding his diet which was restricted to beef jerky, yogurt from a squeeze tube, and fruit drinks. Family history included diabetic peripheral neuropathy in his mother, idiopathic peripheral neuropathy in his maternal grandfather, and left lower extremity neuropathy from trauma in his father. There was no known family history of recurrent pressure palsies or cardiac problems.

Repetitive use of intra-arterial verapamil in the treatment of reversible cerebral vasoconstriction syndrome.

Reversible cerebral vasoconstriction syndrome (RCVS) typically presents with recurrent thunderclap headaches and neurological deficits that are usually self-limiting. The intra-arterial (IA) use of vasodilators for RCVS has been reported for severe cases. Patients with RCVS have the potential for serious and permanent neurological deficits. It is a rare disorder, with a recent surge in the number of reports, and probably continues to be under-diagnosed. We report two patients with RCVS with severe neurological sequelae, treated in a large tertiary hospital. Both patients received high-dose cortico steroids due to the possibility of angiitis of the central nervous system, but they deteriorated neurologically, which suggests that steroids may have a deleterious effect in RCVS. Treatment with IA verapamil resulted in reversal of vasoconstriction, but multiple treatments were necessary. Therefore, IA administration of verapamil is a possible treatment for severe RCVS, but there is only limited sustained improvement in vasodilation that may require repetitive treatments with a currently undetermined optimal treatment interval.