Reproducibility of dynamic computed tomography brain perfusion measurements in patients with significant carotid artery stenosis

Abstract

In longitudinal studies of patients with chronic cerebral ischemia, PCT ratios and either TTP or CBV are more suitable measures than absolute CBF values, because of their considerably lower inter- and intraobserver variability. Differences in CBF between two examinations as high as 30% may be considered as significant in such patients.

Brain computed tomography perfusion may help to detect hemodynamic reconstitution and predict intracerebral hemorrhage after carotid stenting

“…12,13 Finally, the ratios of brain CT perfusion parameters, either TTP or CBV, are suggested to be more adequate measures than absolute values in longitudinal studies because of their considerably lower inter-and intraobserver variability. 14 The reasons why our study showed lack of improvement of cerebral perfusion in patients with bilateral carotid stenosis may be due to, first, the fact that our study used relative CT perfusion values for analysis, and reduced perfusion in the contralateral hemisphere with severe carotid stenosis may result in an overestimated interhemispheric ratio so that the ratio (whether TTP or CBF) may not reflect precise perfusion changes of ipsilateral hemisphere. Second, there is a limited number of patients with bilateral carotid stenosis sufficient for subgroup analysis.…”

A robust noise reduction technique for time resolved CT

“…The changes in perfusion parameters between the PATEN filtered simulated quarter dose and the full dose were similar to levels of the variability (3%-45%) of perfusion parameters reported in the published studies. [41][42][43][44] We also compared these changes to the changes reported for TIPS filtering of a stationary perfusion phantom data 21 (the only study we found in the literature to assess the changes due to filtering) and concluded that both techniques showed similar level of changes for normal tissue, but PATEN filtering showed less changes than TIPS for infarcted CBF and CBV values. Various factors might have caused the variation in perfusion parameters generated from fulldose FBP and PATEN filtered quarter dose images, such as small sample size and inconsistency in reference vessel selection and tissue/vessel segmentation for the generation of perfusion parameter maps.…”

Differences in CT Perfusion Summary Maps for Patients with Acute Ischemic Stroke Generated by 2 Software Packages

“…20,21 Even though there was a high degree of correlation between and within users in producing the CBV, CBF, and MTT maps within a single analysis software package (GE Healthcare), the level of agreement was considered not sufficient to allow quantitative data derived from these maps for clinical decision-making. 21 Recently, it was shown that intravendor differences are the primary cause of the variability in CTP analysis.…”