Small Intracranial Aneurysms: Diagnostic Accuracy of CT Angiography

Abstract

Purpose To assess the accuracy of computed tomographic (CT) angiography for diagnosis of cerebral aneurysms 5 mm or smaller, with digital subtraction angiography (DSA) as the reference standard, in a large patient cohort Materials and Methods This retrospective study was approved by the local institutional review board with a waiver of written informed consent. A total of 1366 patients who underwent cerebral CT angiography followed by DSA were included. The performance of CT angiography for depiction of aneurysms was evaluated by two readers on a per-patient and per-aneurysm basis and based on size of aneurysm, location, and status of rupture. The performance of CT angiography for diagnosis of aneurysms of different size, location, and rupture status was compared by using χ test. κ statistic was used to assess interreader agreement for diagnosis of aneurysms. Results Of 1366 patients, 579 patients had 711 small aneurysms at DSA. By using DSA as the reference standard, the respective sensitivity, specificity, and accuracy of CT angiography for readers 1 and 2 for detection of small aneurysms on a per-patient basis were 97.1% (562 of 579) and 97.4% (564 of 579), 98.5% (451 of 458) and 99.1% (454 of 458), and 97.7% (1013 of 1037) and 98.2% (1018 of 1037) and those on a per-aneurysm basis were 95.2% (677 of 711) and 95.4% (678 of 711), 96.6% (451 of 467) and 97.0% (454 of 468), and 95.8% (1128 of 1178) and 96.0% (1132 of 1179). The sensitivities of CT angiography were lower for detection of aneurysms smaller than 3 mm and unruptured compared with aneurysms that were 3-5 mm and ruptured (P < .001). No difference existed for the sensitivities of CT angiography for diagnosis of aneurysms in the anterior versus posterior circulation (P > .0167). Excellent or good interreader agreement was found for detection of intracranial aneurysms on a per-patient (κ = 0.982) and per-aneurysm (κ = 0.748) basis. Conclusion This large cohort study demonstrated that CT angiography had high accuracy for detection of small cerebral aneurysms, including those smaller than 3 mm. RSNA, 2017 Online supplemental material is available for this article.

Proportion of Variant Anatomy of the Circle of Willis and Association with Vascular Anomalies on Cerebral CT Angiography

“…Persistent embryonic carotid-vertebrobasilar anastomosis such as hypoglossal, proatlantal, otic, and persistent trigeminal arteries are extremely rare occurring in about 0.1%-0.6% of the general population [13]. CT angiography (CTA) is a fast reliable noninvasive method for evaluation of the circle of Willis as well as other intracranial arteries and aneurysms with high sensitivity and specificity comparable to gold standard catheter angiography [14].…”

Spontaneous Acute Subdural Hematoma: Beware of the Aneurysm

“…It is a sensitive, specific, rapid, and cost-effective examination, and it is widely accepted in the literature as a gold standard for workup of a ruptured aneurysm. 9 10 Nevertheless, its timing in the management of patients suffering from ASH due to an aneurysm rupture is still debated in recent publications, 11 12 especially when an emergency surgery is needed. We consider it as necessary for the future care of the patient, regardless of the severity of his clinical and radiological findings on admission.…”

Added diagnostic values of three-dimensional high-resolution proton density-weighted magnetic resonance imaging for unruptured intracranial aneurysms in the circle-of-Willis: Comparison with time-of-flight magnetic resonance angiography

“…With the increase in the demand for health checkups and accessibility to advanced imaging techniques, the detection of incidental aneurysms is increasing [3,4]. However, small infundibular dilatations are sometimes confused with true aneurysms [3,5]. Infundibula are detected on angiography or autopsy with occurrence rates ranging from 7% to 25%, and are generally considered to be benign lesions that do not require treatment or follow-up [4,6].…”