CT Perfusion with Angiography as a Substitute for both Conventional Digital Subtraction Angiography and Acetazolamide-Challenged SPECT in the Follow-Up of Postbypass Patients

Abstract

Background: We evaluated the clinical usefulness of CT perfusion (CTP) with angiography (CTA) as an alternative to digital subtraction angiography (DSA) and acetazolamide (ACZ)-challenged single-photon emission computed tomography (SPECT) in the follow-up evaluation of hemodynamic changes and bypass patency after bypass surgery in chronic cerebral ischemic diseases. Methods: Thirty-five patients who underwent superficial temporal artery/middle cerebral artery bypass surgery for chronic cerebral ischemic diseases were retrospectively enrolled. We assessed the relationship between CTP parameters [cerebral blood volume, cerebral blood flow (CBF), mean transit time (MTT), affected-to-unaffected hemisphere (ATU) ratio of perfusion parameters and MTT differences between hemispheres] and SPECT parameters (regional CBF and cerebrovascular reserve) and compared the preoperative CTP parameters with the postoperative ones. For the bypass patency, we compared CTA with DSA. Results: MTT showed the best correlation with CVR of SPECT (r = –0.343; p < 0.001). ATU ratio (r = –0.547; p < 0.001) and ATU differences (r = –0.592; p < 0.001) of MTT correlated well with the ATU ratio of rCBF on ACZ-challenged SPECT. Significant improvement of perfusion parameters could be demonstrated in the affected vascular territory with postoperative CTP. The CTA findings were consistent with those of DSA in 96% of the cases. The examination-related complication rate was 0, 2.8 and 8.6% for CT studies, DSA and SPECT, respectively. Conclusions: CTP performed simultaneously with CTA seems to be a safe and efficient substitute for DSA and ACZ-challenged SPECT in the follow-up evaluation after bypass surgery in patients with chronic cerebral ischemic diseases.

Prolonged Mean Transit Time Detected by Dynamic Susceptibility Contrast Magnetic Resonance Imaging Predicts Cerebrovascular Reserve Impairment in Patients with Moyamoya Disease

“…They concluded that MTT is the most predictive parameter for assessing decreased CVR. Park et al [21] reported that MTT showed the best correlation with CVR of 99m Tc-HMPAO SPECT in patients with chronic cerebral ischemic disease. Eicker 136 et al [22] showed that all patients with impaired CVR proven by 99m Tc-HMPAO SPECT had delayed MTT and delayed T max in patients with ICA occlusion.…”

Immediate Regression of Leukoaraiosis after Carotid Artery Revascularization

“…Extreme cerebral vasodilatation (larger than 1.2-fold) disrupts the blood-brain barrier causing vasogenic edema to develop [26,27]. Carotid revascularization reduces the collateralization demand thereby normalizing asymmetry of the rCBV and preventing the development of transient vasogenic edema [28]. Notably, the transience of the vasogenic edema suggests that edema contributes to the magnitude of the ‘LA’ score as calculated from FLAIR maps (but not as calculated from DWI maps) [29].…”

Does Perfusion Computed Tomography Facilitate Clinical Decision Making for Thrombolysis in Unselected Acute Patients with Suspected Ischaemic Stroke?

“…High recanalisation rates and good functional outcomes can be achieved by administering combined intravascular and systemic thrombolysis, using perfusion CT to select patients [19]. It can be used to assess tissue status after interventions for chronic cerebral ischaemia [20]. Multimodal CT-assisted thrombolysis may help improve functional outcomes, both within and outside the 3-hour time window, particularly beyond 3 h [21].…”