Evaluation of Cerebral Aneurysm with High Resolution MR Angiography using Slice Interpolation Technique: Correlation with Digital Subtraction Angiography (DSA) and MR Angiography (MRA)

ABSTRACT

PURPOSE: There have been some efforts to diagnose intracranial aneurysm through a non-invasive method using MRA, although the process may be difficult when the lesion is less than 3mm. The present study prospectively compare the results of high resolution, fast speed slice interpolation MRA and DSA therapy examing the potentiality of primary non-invasive screening test. MATERIALS AND METHODS: A total of 26 cerebral aneurysm lesions from 14 patients with subarachnoid hemorrhage from ruptured aneurysm (RA) and 5 patients with unruptured aneurysm(UA). In all subjects, MRA was taken to confirm the vessel of origin, definition of aneurysm neck and the relationship of the aneurysm to nearby small vessels, and the results were compared with the results of DSA. The images were obtained with 1.5T superconductive machine(Vision, Siemens, Erlangen, Germany) on 4 slabs of MRA using slice interpolation. the settings include TR/TE/FA=30/6.4/25, matrix 160x512, FOV 150x200, 7minutes 42seconds of scan time, effective thickness of 0.7mm and an entire thickness of 102.2mm. The images included structures from foramen magnum to A3 portion of anterior cerebral artery. MIP was used for the image analysis, and multiplanar reconstruction(MPR) technique was used in cases of intracranial aneurysm. RESULTS: A total of 26 intracranial aneurysm lesions from 19 patients with 2 patients having 3 lesion, 3 patients having 2 lesions and the rest of 14 patients having 1 lesion each were examined. Among those, 14 were RA and 12 were UA. Eight lesions were less than 2mm in size, 9 lesions were 3-5mm, 7 were 6-9mm and 2 were larger than 10mm. On initial exams, 25 out of 26 aneurysm lesions were detected in either MRA or DSA showing 96% sensitively. Specificity cannot be estimated since there was no true negative of false positive findings. When MRA and MPR were used concurrently for the confirmation of size and shape, the results were equivalent to those of DSA, while in the confirmation of aneurysm neck and parent vessels, the concurrent use of MRA and MPR was far superior to the sole use of either MRA or DSA. CONCLUSION: High resolution MRA using slice interpolation technique showed equal results as those of DSA for the detection of intracranial aneurysm, and may be used as a primary nin-invasive screening test in the future.