Quantitative hemodynamic studies in moyamoya disease: a review

Abstract

Moyamoya disease is characterized by a chronic stenoocclusive vasculopathy affecting the terminal internal carotid arteries. The clinical presentation and outcome of moyamoya disease remain varied based on angiographic studies alone, and much work has been done to study cerebral hemodynamics in this group of patients. The ability to measure cerebral blood flow (CBF) accurately continues to improve with time, and with it a better understanding of the pathophysiological mechanisms in patients with moyamoya disease. The main imaging techniques used to evaluate cerebral hemodynamics include PET, SPECT, xenon-enhanced CT, dynamic perfusion CT, MR imaging with dynamic susceptibility contrast and with arterial spin labeling, and Doppler ultrasonography. More invasive techniques include intraoperative ultrasonography. The authors review the current knowledge of CBF in this group of patients and the role each main quantitative method has played in evaluating them, both in the disease state and after surgical intervention.

Fig. 1

Hemodynamic findings on SPECT studies obtained pre- (a) and postacetazolamide (b) in a 34-year-old patient with bilateral moyamoya disease and previous right occipital artery stroke.

Fig. 2

Preoperative and 1-year postoperative Xe-CT studies obtained with and without acetazolamide (Diamox) in a 45-year-old patient with bilateral moyamoya disease, which was worse in the left hemisphere.

Fig. 3

Hemodynamic findings on MR perfusion studies obtained in a 20-year-old patient with bilateral moyamoya disease, with prolonged Tmax and MTT bilaterally, but worse in the left hemisphere. These MR perfusion studies demonstrate CBF (a); CBV (b); Tmax (c); and MTT (d).

Fig. 4

Neuroimages obtained in a 19-year-old man with moyamoya disease, including FLAIR (a); ASL (b); and bolus DSC (c) MR imaging (Tmax). This patient has involvement of his left posterior cerebral artery territory (arrow), which is clearly distinguished from the normal perfusion in the right posterior cerebral artery territory. The prolonged blood arrival time is confirmed on perfusion-weighted imaging Tmax maps.

Fig. 5

Intraoperative photographs showing blood flow monitoring with the Charbel Transonic Flowprobe before (a) and after (b) STA-MCA microanastomosis for moyamoya disease.

Fig. 6

Studies performed using the NOVA software to assess results in a 55-year-old patient with bilateral moyamoya disease 1 year after STA-MCA bypass on the left side. Blood flow is measured on various arteries of the circle of Willis and the left STA-MCA graft (arrow). Note that a previous right saphenous vein graft can also be seen and measured.