Hironori Kamano MD, Presenter: Nothing to Disclose

Takashi Yoshiura MD, PhD, Abstract Co-Author: Nothing to Disclose

Akio Hiwatashi MD, Abstract Co-Author: Nothing to Disclose

Koji Yamashita MD, Abstract Co-Author: Nothing to Disclose

Koichiro Abe, Abstract Co-Author: Nothing to Disclose

Shingo Baba, Abstract Co-Author: Nothing to Disclose

Hiroshi Honda MD, Abstract Co-Author: Nothing to Disclose

Tuvshinjargal Dashjamts MD, Abstract Co-Author: Nothing to Disclose

Previous studies have suggested that arterial transit time (ATT) measured by arterial spin labeling (ASL) provides useful information regarding hemodynamic impairment in steno-occlusive cerebrovascular diseases. Our purpose was to determine whether ATT correlates with hemodynamic status as assessed by mean transit time (MTT) measured by positron emission tomography (PET).

16patients with chronic steno-occlusive disease (mean age 61 years) were studied at a 3T MR imager using a quantitative ASL sequence implemented with multiple inversion-delay sampling. From the ASL data, maps of cerebral blood flow (CBF) and ATT were generated. Each patient received 15O-PET, from which maps of CBF and cerebral blood volume (CBV) were obtained. All maps from ASL and those from PET were coregistered to a 3D T1-weighted MR image of each patient so that the hemodynamic parameters could be compared within the same location. MTT values were calculated as CBV/CBF. 12 regions-of interest (ROIs) were placed in the anterior, middle, and posterior cerebral artery (ACA, MCA and PCA) territories, anterior and posterior watersheds, and cerebral white matter. All 12 ROIs were used for the CBF analysis, whereas only ROIs in ACA, MCA and PCA territories (6ROIs in bilateral hemispheres) were used for the correlation between ASL-ATT and PET-MTT, since ATT in the white matter and watersheds are known to be physiologically prolonged compared to that in the territorial gray matter. Correlation between the ASL-CBF and PET-CBF and that between ASL-ATT and PET-MTT were assessed by Pearson’s correlation coefficient. In addition, the correlation between the relative values of CBF, ATT and MTT were also compared.

A significant positive correlation was found between ASL-CBF and PET-CBF both in absolute (r=0.520, P < .0001) and relative (r=0.692, P < .0001) values. Comparison between ASL-ATT and PET-MTT resulted in a significant positive correlation both for absolute (r=0.369, P=.0002) and relative (r=0.449, P < .0001) values.

ATT measured by ASL significantly correlated with MTT by PET. Our results suggested that ATT has potential to detect hemodynamic impairment.

Arterial transit time measurement by non-invasive ASL may provide useful information regarding hemodynamic impairment in chronic steno-occlusive cerebrovascular disease.

Kamano, H, Yoshiura, T, Hiwatashi, A, Yamashita, K, Abe, K, Baba, S, Honda, H, Dashjamts, T, ASL Measurement of Arterial Transit Time in Patients with Steno-occlusive Cerebrovascular Diseases: Correlation with 15O-PET Mean Transit Time.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010704.html