The utility of angiographic CT in the diagnosis and treatment of neurovascular pathologies in the vicinity of cranial base

Neurosurgical Review - This study aims to explore the utility of angiographic computed tomography (CT) in the diagnosis and treatment of neurovascular pathologies in the vicinity of cranial base....     

Three-dimensional helical computerized tomography angiography in the diagnosis,characterization, and management of middle cerebral artery aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: Middle cerebral artery (MCA) aneurysms can be difficult to detect and characterize. The authors describe the utility and impact of helical computerized tomography (CT) angiography for the evaluation of aneurysms in this location, and compare this modality with digital subtraction (DS) angiography and intraoperative findings. METHODS: Two hundred fifty-one patients with suspected cerebral aneurysms underwent CT angiography. Two-dimensional multiplanar reformatted images and three-dimensional CT angiograms were examined by two independent readers in a blinded fashion. Results were compared with findings on DS angiograms to determine the relative efficacy of these modalities in the detection and characterization of aneurysms. Questionnaires completed by neurosurgeons and endovascular therapists were used to determine the impact of CT angiograms on aneurysm management. Twenty-eight patients harboring 31 MCA aneurysms and 26 patients without aneurysms were identified using CT angiography. The sensitivity of CT angiography and DS angiography for MCA aneurysms was 97%; both techniques showed 100% specificity. In 76% of evaluations, the CT angiography studies provided information not available on DS angiography examinations. For the characterization of aneurysms, CT angiography was rated superior (72%) or equal (20%) to DS angiography in 92% of cases evaluated (p < 0.001). Computerized tomography angiography was evaluated as the only study needed for patient triage in 82% of cases (p < 0.001), and as the only study needed for treatment planning in 89% of surgically treated (p < 0.001) and in 63% of endovascularly treated cases (p < 0.001). The information acquired on CT angiograms changed the initial treatment plan in 24 (67%) of these 36 complex lesions (p < 0.01). The aneurysm appearance intraoperatively was identical or nearly identical to that seen on CT angiograms in 17 (89%) of 19 of the surgically treated cases. CONCLUSIONS: Computerized tomography angiography has unique advantages over DS angiography and is a viable alternative to the latter modality in the diagnosis, triage, and treatment planning in patients with MCA aneurysms.     

Sixteen-row multislice computed tomography angiography in the diagnosis and characterization of intracranial aneurysms: comparison with conventional angiography and intraoperative findings

OBJECT: The goal of this study was to prospectively compare the effectiveness of 16-slice computed tomography (CT) angiography with that of conventional digital subtraction (DS) angiography and the surgical findings used to detect and characterize intracranial aneurysms. METHODS: Two hundred forty-four consecutive patients underwent both CT angiography and DS angiography no more than 3 days apart. Computed tomography angiography was performed with a 16-row multislice CT scanner in which a collimation of 0.75 mm was used. Two observers independently reviewed the CT images, and 1 of the 3 attending neuroradiologists reviewed the DS angiograms. They determined the presence, location, quantitation, and characterization of the intracranial aneurysms. Statistical results were calculated independently for the image interpretation performed by the 2 CT scan readers and the DS angiogram reader by using the combination of DS angiography or intraoperative findings or both as a reference standard. RESULTS: One hundred thirty-six patients harboring 153 intracranial aneurysms were included in this series. There was no statistically significant difference in sensitivity between 16-slice CT angiography and conventional DS angiography (p > 0.05). The sensitivities of 16-slice CT angiography for aneurysms < 5 mm, 5-10 mm, and > 10 mm were 94.8, 100, and 100%, respectively, on a per-aneurysm basis. The overall sensitivity and specificity of CT angiography for aneurysms were 98.0 and 99.1%, respectively. Sixteen-slice CT angiograms were clearer and more accurate in depicting the relationship of aneurysms to bone structures and adjacent branch vessels. CONCLUSIONS: Computed tomography angiography using a 16-slice scanner is an accurate tool for detecting and characterizing intracranial aneurysms, including small aneurysms. Noninvasive 16-slice CT angiography will become a viable replacement for conventional DS angiography in the diagnosis and characterization of aneurysms.     

Transparent imaging of CT angiography for the delineation of cerebral aneurysms]

Transparent imaging with volume rendering of CT angiography (CTA) was used to delineate cerebral aneurysms. Five unruptured cerebral aneurysms discovered incidentally on MR angiography were delineated as transparent CTA images and compared with routine three-dimensional CTA images. Reconstructing the volume data sets by adjusting the opacity level and range of CT values allowed transparent visualization of the aneurysm with its related vessels through the bony structures of the cranial base. Transparent imaging of CTA may be a useful adjunct for the evaluation of an aneurysm adjacent to the bony structure.     

Volume-rendered helical computerized tomography angiography in the detection and characterization of intracranial aneurysms

OBJECT: The goal of this study was to evaluate the utility of volume-rendered helical computerized tomography (CT) angiography in patients with intracranial aneurysms. The authors compared the abilities of CT angiography, digital subtraction (DS) angiography, and three-dimensional time-of-flight magnetic resonance (MR) angiography to characterize aneurysms. METHODS: Helical CT angiography was performed in 45 patients with suspected intracranial aneurysms by using volume-rendered multiplanar reformatted (MPR) images. Digital subtraction angiography was performed using biplane angiography. These studies and those performed using MR angiography were interpreted in a blinded manner. Two neurosurgeons and two interventional neuroradiologists independently graded the utility of CT angiography with respect to aneurysm characterization. Fifty-five aneurysms were detected. Of these, 48 were evaluated for treatment. Computerized tomography angiography was judged to be superior to both DS and MR angiography in the evaluation of the arterial branching pattern at the aneurysm neck (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.007), aneurysm neck geometry (compared with DS angiography, p = 0.001, and with MR angiography, p = 0.001), arterial branch incorporation (compared with DS angiography, p = 0.021, and with MR angiography, p = 0.001), mural thrombus (compared with DS angiography, p < 0.001), and mural calcification (compared with DS angiography, p < 0.001, and with MR angiography, p < 0.001). For surgical cases, CT angiography had a significant impact on treatment path (p = 0.001), operative approach (p = 0.001), and preoperative clip selection (p < 0.001). For endovascular cases, CT angiography had an impact on treatment path (p < 0.02), DS angiography study time (p = 0.01), contrast agent usage (p = 0.01), and coil selection (p = 0.02). Computerized tomography angiography provided unique information about 39 (81%) of 48 aneurysms, especially when compared with DS angiography (p = 0.003). The sensitivity and specificity of CT angiography compared with DS angiography was 1. The sensitivity and specificity of CT and DS angiography studies compared with operative findings were 0.98 and 1, respectively. CONCLUSIONS: Computerized tomography angiography is equal to DS angiography in the detection and superior to DS angiography and MR angiography in the characterization of brain aneurysms. Information contained in volume-rendered CT angiography images had a significant impact on case management.     

The future of imaging in the management of abdominal aortic aneurysm.

The development of endovascular techniques depends on the concomitant development of imaging techniques. Imaging with ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MR) is evolving at rapid pace. Angiography has largely been replaced by these techniques as a diagnostic tool in the clinical setting. New methods, e.g., rotational angiography and intravascular ultrasound, will play an important role in endovascular treatment of vascular disease. It is necessary to have easy access to ultrasonography, CT and MR images in future hybrid angiographic/surgical suites and the operator must be able to do advanced immediate reconstructions in a sterile environment. The combined use of advanced imaging, open and endovascular techniques will further improve the treatment of vascular disease in the future.     

Laparoscopic lymph node dissection for gastric cancer with intraoperative navigation using three-dimensional angio computed tomography images reconstructed as laparoscopic view

Background: Laparoscopic extended lymph node dissection for gastric cancer is difficult to perform because it requires dissection with preservation of vessels. Therefore, an intraoperative navigation system for the angioarchitecture would be helpful. Recent enhanced volume-rendering computed tomography (CT) can produce clear intraluminal three-dimensional (3D) images. This advanced radiological technology can provide 3D angiographic images reconstructed in the same view as would be observed from a laparoscope inserted into the abdominal cavity. We report our experience with laparoscopic gastrectomy with radical lymph node dissection using this advanced radiological technology. Methods: 3D CT angiographic images from the celiac axis to the proper hepatic artery were reconstructed in two ways preoperatively. The first was only 3D angiographic images that were reconstructed as the laparoscopic view (LapView 3D CT angiography). The second was LapView 3D CT angiography with images of the body of the pancreas, which was more useful for intraoperative navigation in comprehensing anatomy. Two monitors were placed over the shoulder of the patient during surgery. One monitor, which was controlled by the image mixer, projected the laparoscopic images with picture in picture of 3D CT angiographic images. The surgeon performed the surgery with reference to this monitor during lymph node dissection. Results: 3D angiographic CT clearly showed all vessels of interest in laparoscopic lymph node dissection for gastric cancer in 10 cases. The anatomy of vessels appeared as if looking beyond visible surface. LapView 3D CT angiography was useful for laparoscopic navigation surgery. Paper presented at the Scientific Session of the 8th World Congress of Endoscopic Surgery hosted by SAGES, New York, NY, USA, March 2002     

Utility of three-dimensional computed tomographic angiography for assessment of relationships between the vertebrobasilar system and the cranial base

OBJECTIVE: The optimal surgical exposure for basilar tip aneurysms is dictated by the relationship of the basilar bifurcation to the cranial base. This study was designed to evaluate three-dimensional computed tomographic angiography as a means of obtaining detailed anatomic information on the basilar artery and the surrounding cranial base in individual patients before surgery. METHODS: We studied 30 patients using three-dimensional computed tomographic angiographic reconstructions from 1-mm computed tomographic slices. Detailed anatomic measurements were performed to define the relationship between the basilar artery and the cranial base. Particular attention was paid to the height of the dorsum sellae and its relationship to the basilar bifurcation. RESULTS: The heights of the basilar apex and the vertebrobasilar junction, relative to the cranial base, were extremely variable. Considerable asymmetries in the heights of the left and right posterior clinoid processes were identified; in one case, this difference was more than 1 cm (mean difference in height, 0.9 mm; range, 0-10.3 mm). The heights of the posterior clinoid processes above the sellar floor ranged from 5.8 to 14.1 mm (mean height, 9.5 mm). We were able to determine the feasibility of the pterional/orbitozygomatic, middle fossa/ anterior petrosal, and presigmoid retrolabyrinthine approaches to an individual basilar bifurcation. We also estimated the amount of bone removal required and determined the operative distances via those approaches. CONCLUSION: Three-dimensional computed tomographic angiography is a useful tool for assessing critical anatomic relationships and represents an adjunct to conventional angiography in the planning of individualized, precisely tailored, cranial base approaches to the vertebrobasilar system.     

Application of 4D-CTA using 320-row area detector computed tomography on spinal arteriovenous fistulae: initial experience

Time-resolved computed tomography angiography (4D-CTA) using a 320-row area detector CT scanner has recently been applied in the evaluation of cranial vascular disorders. However, application of 4D-CTA to spinal vascular disorder evaluation has never before been described. The authors herein report their initial experience of 4D-CTA in the evaluation of spinal arteriovenous fistulas (AVFs) and compare this novel modality with other imaging modalities. Four consecutive patients with spinal AVF underwent time-resolved contrast-enhanced magnetic resonance angiography (trMRA), 4D-CTA, and selective catheter angiography (CA). In 4D-CTA, volume data was transformed into 3D volume-rendered images and maximum intensity projection. These images were also evaluated by time-resolved serial phases. Then, images of each modality were compared, focusing on the detection of perimedullary draining veins and the prediction of AVF location and drainage flow direction. All modalities successfully detected perimedullary draining veins in all cases. Location of the AVF was detected in all cases by CA. trMRA and 4D-CTA detected the AVF in three out of the four cases. With regard to flow direction, while 4D-CTA successfully depicted ascending or descending drainage flow in the spinal canal, CA failed to detect the flow direction in one case while trMRA failed in two cases. In the case with epidural AVF, 4D-CTA was the only technique to detect the flow direction of perimedullary drainage. Although this is only an initial experience of the application of 4D-CTA to spinal vascular diseases, 4D-CTA was capable of detecting the dynamic vascular flow of spinal AVFs. The authors believe that 4D-CTA can be a useful option in the evaluation of spinal AVFs.     

Three-dimensional angiography for radiosurgical treatment planning for arteriovenous malformations

OBJECT: Radiosurgical treatment of a cerebral arteriovenous malformation (AVM) requires the precise definition of the nidus of the lesion in stereotactic space. This cannot be accomplished using simple stereotactic angiography. but requires a combination of stereotactic biplanar angiographic images and stereotactic contrast-enhanced computerized tomography (CT) scans. In the present study the authors describe a method in which three-dimensional (3D) rotational angiography is integrated into stereotactic space to aid treatment planning for radiosurgery. METHODS: Twenty patients harboring AVMs underwent treatment planning prior to linear accelerator radiosurgery. Planning involved the acquisition of two different data sets, one of which was obtained using the standard method (a combination of biplanar stereotactic angiography with stereotactic CT scanning), and the other, which was procured using a new technique (nonstereotactic 3D rotational angiography combined with stereotactic CT scanning by a procedure of image fusion). The treatment plan that was developed using the new method was compared with that developed using the standard one. For each patient the number of isocenters and the dimension of selected collimators were the same, based on the information supplied in both methods. Target coordinates were modified in only five cases and by a limited amount (mean 0.7 mm, range 0.3-1 mm). CONCLUSIONS: The new imaging modality offers an easier and more immediate interpretation of 3D data, while maintaining the same accuracy in target definition as that provided by the standard technique. Moreover, the new method has the advantage of using nonstereotactic 3D angiography, which can be performed at a different site and a different time with respect to the irradiation procedure.     

Cranial fasciitis of childhood: a case report.

Cranial fasciitis of childhood is very rare, only 17 cases having been reported in the literature. We report an additional case of this rare disease. The patient was a 5-year-old boy who complained of left exophthalmos and double vision. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a large epidural mass in the left frontal region that had invaded into the underlying anterior skull base. The tumor showed homogeneous, low density with nonhomogeneous contrast enhancement on the CT scans, and low intensity on the T1-weighted and high intensity on the T2-weighted MRI images. A whitish-pink, elastic, hard tumor was revealed in the epidural space in the left anterior cranial fossa, which was totally excised with curettage of the affected anterior skull base. The origin of the tumor was suspected to be the fibrous connective tissue of the sphenofrontal suture. The histological diagnosis was that of cranial fasciitis. There was no evidence of recurrence 1 year postoperatively.     

Three-dimensional computerized tomography angiography in patients with hyperacute intracerebral hemorrhage.

OBJECT: The authors confirm the usefulness of extravasation detected on three-dimensional computerized tomography (3D-CT) angiography in the diagnosis of continued hemorrhage and establishment of its cause in patients with acute intracerebral hemorrhage (ICH). METHODS: Thirty-one patients with acute ICH in whom noncontrast and 3D-CT angiography had been performed within 12 hours of the onset of hemorrhage and in whom conventional cerebral angiographic studies were obtained during the chronic stage were prospectively studied. Noncontrast CT scanning was repeated within 24 hours of the onset of ICH to evaluate hematoma enlargement. Findings indicating extravasation on 3D-CT angiography, including any abnormal area of high density on helical CT scanning, were observed in five patients; three of these demonstrated hematoma enlargement on follow-up CT studies. Thus, specificity was 60% (three correct predictions among five positives) and sensitivity was 100% (19 correct predictions among 19 negatives). Evidence of extravasation on 3D-CT angiography indicates that there is persistent hemorrhage and correlates with enlargement of the hematoma. Regarding the cause of hemorrhage, five cerebral aneurysms were visualized in four patients, and two diagnoses of moyamoya disease and one of unilateral moyamoya phenomenon were made with the aid of 3D-CT angiography. Emergency surgery was performed without conventional angiography in one patient who had an aneurysm, and it was clipped successfully. CONCLUSIONS: Overall, 3D-CT angiography was found to be valuable in the diagnosis of the cause of hemorrhage and in the detection of persistent hemorrhage in patients with acute ICH.     

Application of Three-dimensional Reconstruction in Esophageal Foreign Bodies

This study was conducted to investigate the clinical application of three-dimensional (3D) reconstructed computed tomography (CT) images in detecting and gaining information on esophageal foreign bodies (FBs). Two patients with esophageal FBs were enrolled for analysis. In both cases, 3D reconstructed images were compared with the FB that was removed according to the object shape, size, location, and orientation in the esophagus. The results indicate the usefulness of conversion of CT data to 3D images to help in diagnosis and treatment. Use of 3D images prior to treatment allows for rapid prototyping and surgery simulation.     

Surgical treatment of poorly visualised and complex cerebrovascular lesions using pre-operative angiographic data as angiographic DynaCT datasets for frameless stereotactic navigation

Background  

Digital subtraction angiography (DSA) is the “gold standard” for the imaging of cerebrovascular lesions, particularly cerebral aneurysms and arteriovenous malformations (AVMs). Current stereotactic navigation is based on computed tomography (CT) and magnetic resonance (MR) images, which—even despite the use of CT angiographic (CTA) or MR angiographic (MRA) sequences—may not reveal small lesions, and may not demonstrate all the different facets of complex lesions.     

动脉栓塞治疗肾血管平滑肌脂肪瘤破裂出血

目的评价选择性动脉栓塞治疗肾血管平滑肌脂肪瘤破裂出血的安全性和有效性。方法3例经B超、CT确诊的肾血管平滑肌脂肪瘤患者,左肾1例,右肾1例,双肾1例,突然出现腰腹痛、神志淡漠,血压下降等出血症状,急诊行选择性肾动脉造影和栓塞治疗,栓塞剂用无水酒精和弹簧圈。结果3例患者造影发现:肿瘤区血管紊乱并有动脉瘤形成,栓塞后造影显示:肿瘤血管血供减少,肿瘤内载有动脉瘤血供闭塞。无严重并发症出现。术后随访患者血压上升,临床症状改善。结论选择性动脉栓塞治疗肾血管平滑肌脂肪瘤破裂出血,能有效地控制出血并能最大限度保护正常肾组织,应作为急诊出血首选治疗方法。     

Comparing accuracy of cerebral aneurysm size measurements from three routine investigations: computed tomography, magnetic resonance imaging, and digital subtraction angiography

Modern imaging technologies, such as computed tomography (CT) angiography, magnetic resonance (MR) angiography, and digital subtraction (DS) angiography are widely used for pretreatment evaluation of cerebral aneurysms, but the relative accuracies of these modalities are unclear. This study compared the measurements of aneurysm neck and dome height and width on CT angiography, time-of-flight (TOF)-MR angiography, and DS angiography using a three-dimensional workstation. An elastic model of a side-wall aneurysm was connected to an artificial heart pulsatile circuit system. The aneurysm model was prepared using a silicone membrane of 0.6-mm thickness under normal physiological circulation parameters. Using this aneurysm model, three-dimensional TOF-MR angiography, contrast-enhanced CT angiography, and DS angiography were performed. Source images were post-processed on a dedicated workstation to calculate the aneurysm size. DS angiography measurements were found to be the most accurate. In contrast, aneurysm neck sizes measured on CT angiography were significantly wider than actual values (p < 0.05) and aneurysm heights measured using TOF-MR angiography were significantly lower than actual values (p < 0.01). In this in-vitro model, at least one aneurysm dimension measured with CT angiography and with TOF-MR angiography differed significantly from actual values. Aneurysm neck width markedly affects therapeutic planning, as a wide neck requires craniotomy or endovascular treatment using an adjunctive device, so inaccuracies should be considered when aneurysm treatment is planned using modern methods of visualization.     

Thrombosed giant aneurysm of the pericallosal artery with inconclusive findings of multiple neuroimaging studies

A 65-year-old woman presented with a thrombosed giant pericallosal artery aneurysm manifesting as headache and memory loss that developed over a 2-year period. Computed tomography (CT), magnetic resonance (MR) imaging, and conventional and CT angiography could not establish the differential diagnosis. Open craniotomy revealed the mass as thrombosed giant aneurysm from the pericallosal artery. Direct clipping with thrombectomy was performed successfully with an uneventful postoperative course. Thrombosed giant aneurysm of the distal anterior cerebral artery should be considered in the differential diagnosis of an unusual mass in the mid-frontal area, particularly in the presence of inconclusive angiographic and MR imaging findings.     

Three-dimensional computerized tomography angiography in the diagnosis of cerebrovascular disease.

Computer-generated three-dimensional reconstruction of the intracranial vascular system obtained by contrast-enhanced computerized tomography (CT) has been used in the diagnosis of 20 patients with known or suspected intracranial cerebrovascular disease. This technique allows visualization of the intracranial vasculature without exposing patients to the risks associated with intra-arterial angiography. The color prints and videotape images generated have been used to diagnose the presence of intracranial aneurysms, arteriovenous malformations, and venous angiomas. They have also been used to rule out structural abnormalities in patients with suspected intracranial vascular pathology and to screen patients with a strong family history of intracranial aneurysm. In 11 patients who underwent both three-dimensional CT angiography and intra-arterial angiography, the diagnostic correlation was 100%. No complications from the procedures or from incorrect diagnosis have been encountered. Although this technique requires further development and clinical evaluation, the authors' early experience with three-dimensional CT angiography suggests that this may become a valuable tool in the diagnosis of patients with cerebrovascular disease.     

Celiomesenteric trunk with concurrent aneurysm: Report of a case

This report describes a rare case of a common celiomesenteric anomaly with a concurrent aneurysm demonstrated by contrast-enhanced multidetector computed tomography (MDCT) angiography. The patient, a 53-year-old man, had no abdominal pain or discomfort. Abdominal CT scanning was performed because of hypoglycemia. Celiac digital subtraction angiography (DSA) was carried out 10 days after CT angiography. The CT angiographic images clearly showed a saccular aneurysm originating from the bifurcation of a common celiomesenteric trunk. The origin and course of the hepatic, splenic, and superior mesenteric arteries were also visualized. These findings were confirmed by intraarterial DSA. The lesion was resected surgically because of the risk of a rupture of the aneurysm, and the superior mesenteric artery was replanted into the celiomesenteric trunk.