Sixty-four-row multisection CT angiography for detection and evaluation of ruptured intracranial aneurysms: interobserver and intertechnique reproducibility

Abstract

Background and purpose: The purpose of this work was to assess intertechnique and interobserver reproducibility of 64-row multisection CT angiography (CTA) used to detect and evaluate intracranial aneurysms.

Materials and methods: From October 2005 to November 2006, 54 consecutive patients with nontraumatic subarachnoid hemorrhage (SAH) underwent both CTA and digital substraction angiography (DSA). Four radiologists independently reviewed CT images, and 2 other radiologists reviewed DSA images. Aneurysm diameter (D), neck width (N), and the presence of a branch arising from the sac were assessed.

Results: DSA revealed 67 aneurysms in 48 patients and no aneurysm in 6 patients. Mean sensitivity and specificity of CTA for the detection of intracranial aneurysms were, respectively, 94% and 90.2%. For aneurysms less than 3 mm, CTA had a mean sensitivity of 70.4%. Intertechnique and interobserver agreements were good for the detection of aneurysms (mean kappa = 0.673 and 0.732, respectively) and for the measurement of their necks (mean kappa = 0.753 and 0.779, respectively). Intertechnique and interobserver agreements were excellent for the measurement of aneurysm diameters (mean kappa = 0.847 and 0.876, respectively). In addition, CTA was accurate in determining the N/D ratio of aneurysms and adjacent arterial branches. However, the N/D ratio was overestimated by all of the readers at CTA.

Conclusion: Sixty-four-row multisection CTA is an imaging method with a good interobserver reproducibility and a high sensitivity and specificity for the detection and the morphologic evaluation of ruptured intracranial aneurysms. It may be used as an alternative to DSA as a first-intention imaging technique in patients with SAH.

Fig 1.

Images obtained in a 49-year-old woman with SAH. A, 3D volume-rendered CTA image in lateral view shows a 1.5-mm ruptured aneurysm (arrow) at the junction between the A2 segment of the right anterior cerebral artery and a second anterior communicating artery that is fenestrated (line). B, Lateral projection from presurgical treatment 3D DSA shows the same aneurysm as in A.

Fig 2.

Images obtained in a 48-year-old man with SAH. A, 3D volume-rendered CTA image in frontal view shows a left-ruptured MCA bifurcation aneurysm. The relationship between the aneurysm neck and the MCA bifurcation branches is clearly seen on CTA images. B, Frontal projection from pre-embolization DSA, performed with contrast material injection into the left ICA, shows the same aneurysm as in A.

Fig 3.

Images obtained in a 64-year-old woman with SAH. A, 3D volume-rendered CTA image in frontal view shows 2 aneurysms: a large left-ruptured ICA bifurcation aneurysm with the A1 segment from the anterior cerebral artery arising from the sac (arrow) and a small left unruptured posterior communicating artery aneurysm (line). B, Frontal projection from pre-embolization DSA shows the same aneurysms as in A.

Fig 4.

Images obtained in a 44-year-old woman with SAH. A, 3D volume-rendered CTA image in oblique view shows a small anterior communicating aneurysm. Adjacent A2 segment from both anterior cerebral arteries “seem” to be incorporated within the aneurysm wall (arrow). B, Oblique view from pre-embolization DSA shows that both A2 segments are clearly separated from the aneurysm neck and sac.