Radiology: 64-slice CT angiography could be initial test for intracranial aneurysms
Qi Li, MD, from the department of neurology at First Affiliated Hospital, Chongqing Medical University in Chongqing, China, and colleagues studied 108 patients suspected of having intracranial aneurysms. All patients underwent both 64-slice CTA and digital subtraction angiography (DSA).
According to the authors, DSA is the current method of choice for detecting and characterizing intracranial aneurysms. But, it is an invasive technique that has an associated risk of permanent neurological complications. In their study, the authors used the combined interpretations of DSA and surgical findings to determine the accuracy of CTA in detecting aneurysms. A total of 106 intracranial aneurysms were detected at DSA in 96 patients. One aneurysm was found using CTA that was not revealed by DSA.
Of those 107 aneurysms, Li and colleagues reported, CTA helped detect 106 aneurysms in 96 patients. In interpreting the CT angiograms, the first of two readers correctly identified 105 aneurysms and the second correctly identified 106. The missed aneurysms were both present on the CT and were retrospectively identified by the readers.
Sensitivity, specificity and positive and negative predictive values were calculated based on the size of the detected aneurysm. For aneurysms smaller than 3 mm, sensitivity was 93.7 percent for one reader and 96.8 percent for the other. However, sensitivity was 100 percent for both readers for aneurysms larger than 3 mm.
The authors reported that compared with previous studies of 64-slice CTA, they were able to demonstrate high sensitivity for aneurysms smaller than 3 mm.
“The improved diagnostic accuracy of our study depends, in large part, on the technical advancements of multidetector CT scanners,” the authors said. “The increased speed of 64-section scanners facilitates the coupling of image acquisition with peak vascular enhancement, which may provide isotropic data with spatial resolution comparable to those of DSA, The improved detection of aneurysms smaller than 3 mm is also potentially related to the experience of the investigators over time with CT angiography.”
The authors also said their study suggests than not only can therapeutic decisions be made using information provided by CTA, but that it could also help in deciding whether or not to use the placement of a surgical clip or an endovascular coil as treatment for patients.
“Sixty-four–section CT angiography is an accurate imaging method for the detection and treatment planning of intracranial aneurysms,” the authors conclude, “and in most cases, could supplement DSA as the primary method of choice in the diagnostic work-up of patients with subarachnoid hemorrhage.”