Three-Dimensional Computed Tomographic Angiography with Volume Rendering Technique in the Evaluation of Intracranial Aneurysms: Comparison with Three-Dimensional Digital Subtraction Angiography

PURPOSE: The author compared three-dimensional computed tomographic angiography with combined volume rendering technique (3D-CTA VR) with three-dimensional digital subtraction angiography (3D-DSA) in the detection and characterization of intracranial aneurysms, in order to assess the diagnostic capability of 3D-CTA VR. MATERIALS AND METHODS: This study included 50 patients with suspected intracranial aneurysm who underwent both 3D-CTA VR and 3D-DSA, and who were subsequently confirmed as having aneurysms by intracranial operation or other neurointerventional procedures. The detectability and the characteristics of the aneurysms, such as their aneurysmal neck, direction, and vasospasm of the adjacent vessels, were evaluated retrospectively. RESULTS: Sixty-five intracranial aneurysms were detected through surgery or other interventional procedures. 3D-DSA was more sensitive (96.92%) than 3D-CTA VR in the detection of the aneurysms. All of the aneurysms that were more than 3mm in size were detected with both techniques. 3D-DSA failed to reveal one posterior communicating artery aneurysm, while 3D-CTA VR missed three aneurysms. The aneurysmal necks were clearly visualized in 58 of 61 aneurysms (95.1%) on 3D-CTA VR, but all of the aneurysmal necks(100%) were clearly identified on 3D-DSA. CONCLUSION: 3D-CTA combined with VR technique showed good sensitivity for the depiction of intracranial aneurysms greater than 3 mm in size, and its usefulness in characterizing the aneurysms for surgical or endovascular treatment planning was equal to or less than that of 3D-DSA.

Traumatic Intracranial Aneurysms in Children

PURPOSE: To describe the imaging findings of traumatic intracranial aneurysms (TICA) in children. MATERIALS AND METHODS: Five boys aged 3-15 (mean, 7) years with surgically confirmed TICA were included in this study. All had a history of nonpenetrating head trauma, and they underwent precontrast CT imaging immediately after the injury and follow-up CT or MRI. In all cases, angiography revealed the presence of aneurysms, which at surgery were shown to be pseudoaneurysms with severe adhesions. RESULTS: Angiography demonstrated that all aneurysms were located in the anterior cerebral artery (ACA) or its branches. The precise locations were the A2 segment of the ACA, the site of origin of the callosomarginal artery or its first branch, or of the anterior internal frontal artery, or between the first and second branch of the pericallosal artery. In all patients, precontrast CT performed immediately after trauma depicted subarachnoid hemorrhage (SAH) in the anterior interhemispheric fissure (AIHF). Follow-up precontrast CT showed nodular high density around the anterior falx in three, recurrent SAH in the AIHF in two, and intracerebral hemorrhage (ICH) with intraventricular hemorrhage in two. In two patients with a nodular high-density lesion, nodular enhancement was demonstrated at postcontrast CT, and in one, follow-up MRI revealed a nodular signal void around the anterior falx; nodular enhancement was seen at postcontrast imaging, and MR angiogram depicted a saccular aneurysm. In one patient, MRI demonstrated infarction in the caudate nucleus and ACA territory. CONCLUSION: If, after head injury, an area of nodular high density is revealed by CT, or a signal void by MRI, or if SAH or ICH is present around the anterior falx, the possibility of TICA should be considered.

Helical CT Angiography of the Whole Aorta and Iliac Arteries by Injection of Split Bolus Contrast Media: Comparison with single Bolus Injection Technique

PURPOSE: To compare the efficacy of the split-bolus contrast media injection technique in helical CTangiography(CTA) of the whole aorta and iliac arteries with that of the single-bolus technique. MATERIALS AND METHODS: Using the split bolus technique in 23 patients, 90 ml of contrast medium (Ultravist 300) was injected ata rate of 3ml/sec;this was followed by an 8-sec pause and the subsequent injection of 30ml. Using the single bolustechnique in another 23 patients, 120ml of contrast medium was injected for 40sec. continuously. CT angiography ofthe thoracic aorta (slice thickness/pitch=3mm/2:1) was performed, first followed by an interscan delay of 8sec,and the abdominal aorta and iliac arteries were then scanned(slice thickness/pitch=3mm/2:1 or 5mm/1.5:1). In allpatients, CT density was measured in the aortic lumen at eight levels, from the origin of the aorta to the iliacbifurcation. RESULTS: Using the split bolus technique, visual assessment revealed second density peak in theaortic lumen of the upper abdomen in 15 of 23 patients(65%), while the use of the single bolus technique revealedno second density peak in any patient. CT density in the aortic lumen at the level of the esophagogastricjunction, and at all levels below this except the abdominal aortic bifurcation, was significantly higher using thesplit bolus technique than with the single bolus technique (t-test, p<0.05). CONCLUSION: For CTA of the wholeaorta and iliac arteries, the split bolus technique is more effective than the single bolus technique.

Various Complications of Abdominal Aortic Aneurysm: CT Findings

PURPOSE: To evaluate on abdominal CT the type and incidence of various complications of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: Twenty six suspected cases of AAA were confirmed by operation(n=21) and by CT(n=5). The etiology, size, shape and incidence of various complications of AAA were then retrospectively evaluated. In addition, post-operative complications were also evaluated in five cases. RESULTS: The etiology ofthe aneurysm was atherosclerotic in 18 cases and mycotic in three ; it showed the presence of Behcet disease in three cases, of tuberculosis in one, and of Marfan syndrome in one. Among the 18 fusiform AAA, the mean maximum diameter of ruptured AAA(7.5+/-3.3cm, n=3) was significantly larger than that of unruptured AAA(4.9+/-1.6cm, n=15)(p<0.05). The saccular type was much more likely to rupture than the fusiform type(p<0.00001). Out of the eight saccular AAA, seven ruptured ; their mean maximum diameter was 3.9+/-1.3cm This was significantly smaller than that of ruptured fusiform aneurysm(p<0.05). The most common complication was rupture, and occurred ten of 26 cases(38%). Others included hydronephrosis in three cases, bowel infarction in one, and perianeurysmal retroperitoneal fibrosis in one case. Various post-operative complications developed in five patients ; these comprised periprosthetic pseudoaneurysm with hematoma (two cases), bowel ischemia (one), focal renal infarction(one), and secondary aorticoduodenal fistula (one). CONCLUSION: The most common complication of AAA was rupture, the rate of which was much higher in the saccular type with smaller size than the fusiform type. Other various and uncommon complications were observed. CT was helpful in detecting complications arising from AAA and in planning its treatment.

Various Complications of Abdominal Aortic Aneurysm: CT Findings

PURPOSE: To evaluate on abdominal CT the type and incidence of various complications of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: Twenty six suspected cases of AAA were confirmed by operation(n=21) and by CT(n=5). The etiology, size, shape and incidence of various complications of AAA were then retrospectively evaluated. In addition, post-operative complications were also evaluated in five cases. RESULTS: The etiology ofthe aneurysm was atherosclerotic in 18 cases and mycotic in three ; it showed the presence of Behcet disease in three cases, of tuberculosis in one, and of Marfan syndrome in one. Among the 18 fusiform AAA, the mean maximum diameter of ruptured AAA(7.5+/-3.3cm, n=3) was significantly larger than that of unruptured AAA(4.9+/-1.6cm, n=15)(p<0.05). The saccular type was much more likely to rupture than the fusiform type(p<0.00001). Out of the eight saccular AAA, seven ruptured ; their mean maximum diameter was 3.9+/-1.3cm This was significantly smaller than that of ruptured fusiform aneurysm(p<0.05). The most common complication was rupture, and occurred ten of 26 cases(38%). Others included hydronephrosis in three cases, bowel infarction in one, and perianeurysmal retroperitoneal fibrosis in one case. Various post-operative complications developed in five patients ; these comprised periprosthetic pseudoaneurysm with hematoma (two cases), bowel ischemia (one), focal renal infarction(one), and secondary aorticoduodenal fistula (one). CONCLUSION: The most common complication of AAA was rupture, the rate of which was much higher in the saccular type with smaller size than the fusiform type. Other various and uncommon complications were observed. CT was helpful in detecting complications arising from AAA and in planning its treatment.