This is a 15 year-old female with a history of three prior embolizations of a cerebral AVM. She developed a persistent headache after the most recent embolization procedure. What is the likely cause of uptake on the brain flow study?
Intraoperative rupture of the right frontpareital AVM. Noncontrast CT: Diffuse subarachnoid hyperdensities consistent with a mixture of subarachnoid hemorrhage and radiological contrast. There are also hyperdensities consistent with hemorrhage in the right frontotemporal region. Brain swelling and midline shift is also noted. Angiography: frontoparietal AVM with feeders from the right MCA, ACA, and posterior cerebral artery branches. Right MCA catheterization was complicatred by rupture of the feeders/AVM nidus resulting in the bleeds. Brain Flow Scintigraphy: Focal radiotracer accumulation in the right high cerebral hemisphere.
Procedure-Related Brain Hemorrhage
If one to look at the brain study flow without reviewing the patient's history of prior imaging studies, a conclusion could possibly reached that the activity over the right head region could be a site of bandage, etc. For this case, this correlates to the bleeding in the right frontoparietal region which was seen on other images and was caused by intraprocedural catheter rupture of the AVM in that region.
1) Intraparenchymal bleed
2) Bleeding into bandage material overlying the head These are really the only two differentials in this case.
Performing combined SPECT/CT would have been useful in this case (and was not performed for this study). This would have allowed localization of the area of focal radiotracer uptake to the area of AVM rupture as seen on the subsequent noncontrast CT. Also, the subarachnoid hemorrhage could have been identified on the SPECT/CT.