The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

Abstract

Background:The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm.Objectives:The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms.Patients and Methods:Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data.Results:Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms.Conclusions:BSCTA is easily accessible, less time consuming, and most importantly, a non-invasive technique for detecting intracranial aneurysms. It is also suitable for patients who have been referred to emergency services. Therefore, it can be used in emergency conditions and as a first-line diagnostic method in patients with non-traumatic SAH.

Velocity Measurement in Carotid Artery: Quantitative Comparison of Time-Resolved 3D Phase-Contrast MRI and Image-based Computational Fluid Dynamics

“…Rigid wall assumption may also lead to errors (3); although in this study, comparing the anatomical images in different cardiac phases, it was clear for authors that this assumption may not affect the results. Rotational angiography, computed tomography angiography, and MR angiography are currently being used for building 3D models of vascular anatomy (26); however, in this work, 3D geometrical model for CFD was constructed from high resolution time-of-flight MR angiograms that provided more accurate model than phase contrast magnitude images; however, in PC MRI, phase contrast magnitude images were used to segment the vessel from surrounding tissue, which might lead to underestimations of the vessel and this might result in errors while comparing CFD and PC MRI. However, CFD analysis is able to provide a detailed divergence-free velocity vector field with strong quality in rotational components of the velocity vectors.…”

Perimesencephalic hemorrhage with negative angiography: case illustration

“…This modality remains slightly more sensitive than CTA and conventional DSA at this time. 2,4 Prospective studies are needed to ascertain whether detection and treatment of these aneurysms confer a benefit. …”