Yuji Akiyama, Presenter: Nothing to Disclose

Toshinori Matsushige, Abstract Co-Author: Nothing to Disclose

Yoshiko Iwakado, Abstract Co-Author: Nothing to Disclose

Yoko Kaichi, Abstract Co-Author: Nothing to Disclose

Tokunori Kimura PhD, Abstract Co-Author: Nothing to Disclose

Kazuo Awai MD, Abstract Co-Author: Research Grant, Toshiba Corporation Research Grant, Hitachi Ltd Research Grant, Bayer AG Research Consultant, DAIICHI SANKYO Group Research Grant, Eisai Co, Ltd

Hybrid of opposite-contrast magnetic resonance angiography (HOP-MRA) is a new technique that combines the advantages of 3D time-of-flight (TOF) MRA and flow-sensitive black-blood (FSBB) MRA. Theoretically, HOP-MRA demonstrates atherosclerotic plaques including fat as high- and the blood space as low-signal intensity areas in intracranial aneurysms. The purpose of this study was to investigate whether HOP-MRA demonstrates atherosclerotic plaques in intracranial aneurysms.      

This prospective study included 13 patients (6 men, 7 women; median age 63 years, range 24-76 years) with 15 aneurysms. The same neurosurgeon with 15 years of experience confirmed the macroscopic findings on all aneurysms. The median maximum diameter of the aneurysms was 5.1 mm (range 2.8-14.1 mm). All images were acquired on a commercially available 3T MR scanner (Vantage Titan 3T; Toshiba Medical Systems) with a 16-channel head coil. For HOP-MRA we used a 3D GRE double-echo sequence. The scan parameters were: TR, 21 ms; TE1, 3.3 ms; TE2, 13.9 ms; flow dephasing gradient (b=0.3s/mm2); flip angle, 20; field of view, 24 cm; slice thickness, 1 mm; number of partitions, 60; 192 Χ 256 matrix; and 2 NEX. We measured the relative signal intensity (RSI) of the high-intensity area to the background low-intensity area inside the aneurysm. Macroscopic findings of atherosclerotic plaque were classified into 3 grades by the operating neurosurgeon as grade A (entire aneurysm filled with atherosclerotic plaque), grade B (aneurysm partially filled with atherosclerotic plaque), and grade C (no atherosclerotic plaques in the aneurysm).

During surgery, 6 aneurysms were classified as grade A, 4 as grade B, and 5 as grade C. The mean RSI for grade A, B, and C was 4.65±1.53 (standard deviation), 1.42±0.69, and 0.93±0.16, respectively. There was a statistically significant difference between grade A and B (p=0.028, Steel-Dwass multiple comparison), grade A and C (p=0.017), and grade B and C aneurysms (p=0.038).

The relative signal intensity in intracranial aneurysms on HOP-MRA images accurately correlated with the presence and extent of atherosclerotic plaques.

HOP-MRA is a promising modality for predicting the degree of atherosclerotic change in the cerebral arteries.

Akiyama, Y, Matsushige, T, Iwakado, Y, Kaichi, Y, Kimura, T, Awai, K, Evaluation of the Atherosclerotic Wall of intracranial Aneurysms Using Hybrid of Opposite-contrast Magnetic Resonance Angiography (HOP-MRA).  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001268.html