Abstract TP36: Novel Imaging Technique For Evaluation of Carotid Stenosis Using MRI with 3D Fast- Spin- Echo

Abstract

[Purpose] Multi-modalities, such as carotid ultrasound, MRI for plaque imaging, CT angiography (CTA), and angiography, have been utilized for diagnosis of carotid artery stenosis. However, we encounter a situation that high cervical internal carotid artery stenosis makes carotid ultrasound difficult, and a situation that renal dysfunction restricts the use of contrast agent for aforementioned angiography. In evaluation of carotid stenosis, we have recently performed 3D Fast-Spin-Echo MRI (CUBE®, GE medical, USA) with modified sequence, which is completely non-contrast image, and we compared the results from CUBE with modified sequence with that from CTA. [Materials and Methods] Five patients with carotid stenosis underwent both CTA and CUBE with modified sequence. Sequence was optimized to be black as long as the vessel lumen visualization is possible. Images taken with both modalities were processed on 3D workstation (Ziostation, Amin, Japan), and stenosis rate was determined with North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria. [Results] Optimized Sequence is as following: TR 600msec, efTE 13.9msec, BW 62.5kHz, ETL 10, NEX 0.5, matrix 256 × 256, slice thickness 0.8mm, scan time 8:29, FOV 21 × 21cm. Each stenosis rate in the CTA group was 42.2%, 37.5%, 27.3%, 21.6%, and 53.8%. On the other hand, each stenosis rate in the CUBE with modified sequence was 43.5%, 40.8%, 23.6%, 24%, and 19%. Average difference between two modalities among five cases was 2.3% (1.3-3.7%). [Discussion and Conclusion] The results obtained from the CUBE with modified sequence shows similar stenosis rate to that obtained from the CTA. Moreover, yet non-contrast imaging, the vascular lumen was well delineated without being affected by metal artifacts and calcification. This result suggests that CUBE with modified sequence is useful as one of evaluation method for patients with carotid stenosis in addition to conventional modalities.