Three-dimensional CT angiography for the surgical management of the vertebral artery-posterior inferior cerebellar artery aneurysms

Antegrade recanalization of parent artery in proximal occlusion of distal posterior inferior cerebellar artery ruptured aneurysm: A case report

RATIONALE

Distal posterior inferior cerebellar artery (PICA) aneurysms are extremely rare. Herein, we describe a case of PICA pseudoaneurysm with proximal occlusion achieved using detachable coils, but antegrade recanalization, which showed a normal PICA configuration on follow-up angiography. Possible mechanisms of the recanalization and lesions are also discussed.

PATIENT CONCERNS

The patient was an 80-year-old woman with a subarachnoid hemorrhage (SAH) resulting from a distal PICA-ruptured aneurysm, initially misdiagnosed as a non-aneurysmal traumatic SAH.

DIAGNOSIS

On hospitalization day 10, the patient developed rebleeding, and brain computed tomography angiography confirmed a distal PICA pseudoaneurysm.

INTERVENTION

Endovascular coil embolization was performed. Inevitably, the proximal PICA was occluded using detachable coils, and complete occlusion of the affected PICA was confirmed on the final angiogram.

OUTCOME

Fortunately, the patient recovered fully without any neurological sequelae. One year after the procedure, a follow-up angiography was performed, which revealed recanalization of the previously occluded PICA, with normal configuration and no visible aneurysmal dilatation.

CONCLUSION

Even if the SAH is scanty and predominantly in the perimesencephalic cistern, performing a catheter-based angiography is essential. In the case of proximal occlusion of the parent artery without internal trapping in endovascular treatment of PICA pseudoaneurysm, follow-up examination with a short-term angiography might be crucial.

Posterior Inferior Cerebellar Artery Aneurysm: Have You Ever Been Misdiagnosed?

RATIONALE AND OBJECTIVES

The posterior inferior cerebellar artery aneurysm (PICAA), especially distal PICAA, is easily missed by a doctor, leading to misdiagnosis and treatment delays. The objective of this article is to report the computed tomography angiography (CTA) presentations of 30 cases of PICAA proved by digital subtraction angiography (DSA) or surgical operation, and analyze the causes of misdiagnosis of PICAA by CTA.

MATERIALS AND METHODS

Thirty cases of patients with PICAA that were proved by DSA or surgical operation were included in this study, all of whom underwent CTA before surgical procedure. The relationship between the locations of PICAA and the rates of missed diagnosis by CTA was analyzed. The detection rates of the PICAA by volume rendering (VR) images and original thin axial images of CTA were compared.

RESULTS

Twelve cases (12 of 30, 40%) of aneurysm lied on the proximal end of posterior inferior cerebellar artery (PICA) (border with vertebral artery) and all of them (12 of 12,100%) were clearly displayed on the VR images of CTA and correctly diagnosed by doctors. Eighteen cases (18 of 30, 60%) of aneurysm lied on the distal part of the PICA, whereas only 2 of them (2/18, 11.1%) were displayed on the VR images and correctly diagnosed before surgical procedure. After surgical operation, the respective review of the CTA images demonstrated that all aneurysms (30 of 30, 100%) can be found on the thin axial images after careful observation and are shown on VR images after adjusting the display threshold when the locations of the PICAA through thin axial images were known, including the distal PICAA.

CONCLUSIONS

Thin axial CT images are most important and reliable for the detection of distal PICAA. Overdependence on three-dimensional VR images of CTA is the main cause of misdiagnosis.

Anatomic Features of Paraclinoid Aneurysms: Computed Tomography Angiography Study of 144 Aneurysms in 136 Consecutive Patients

BACKGROUND

Paraclinoid aneurysms are among the most challenging aneurysms to treat. Computed tomography (CT) angiography helps in evaluating the radiological characteristics of these aneurysms next to bony structures.

OBJECTIVE

To present the CT angiography characteristics of paraclinoid aneurysms in order to better understand such pathology.

METHODS

The study examined CT angiography-based anatomical characteristics obtained retrospectively from 136 patients with 144 paraclinoid aneurysms selected from single-defined catchment populations in Finland. We examined the diameters of the parent artery (internal carotid artery), the location of the aneurysm, its dimensions (width, height, neck), and aneurysm wall irregularity.

RESULTS

We analyzed 144 paraclinoid aneurysms in 136 patients admitted to the hospital during 2000-2014. Multivariable analysis reveals that rupture aneurysms have the following radiological features: aneurysm larger than 5 mm in diameter (P = .006), irregular wall (P = .046), superior location, larger aspect ratio (P = .039), and neck wider than parent artery (P < .001).

CONCLUSION

Smaller diameter of the internal carotid artery and superior location, as well as a large and irregular aneurysm wall, are radiological characteristics of ruptured paraclinoid aneurysms, which CT angiography can measure easily.

Retrograde stent placement for coil embolization of a wide-necked posterior inferior cerebellar artery aneurysm

Wide-necked aneurysms of the posterior inferior cerebellar artery (PICA) are infrequently encountered in cerebrovascular practice, and endovascular treatment is difficult or impossible even with the use of several neck remodeling techniques. We present the case of a patient with a wide-necked aneurysm of the PICA, which was treated by the retrograde stenting through the contralateral vertebral artery and vertebrobasilar junction with antegrade coil embolization.

Detection and Characterization of Intracranial Aneurysms with Dual-Energy Subtraction CTA: Comparison with DSA

BACKGROUND

to investigate the diagnostic performance of dual-energy subtraction CTA in evaluating intracranial aneurysms by comparison with DSA.

METHODS

ninety-seven patients with suspected intracranial aneurysms were included into our study and completed both 64-section dual-energy subtraction CTA and DSA examinations. Two independent readers retrospectively reviewed all subtraction CTA images in a blinded manner. Sensitivity, specificity, positive predictive value and negative predictive value of subtraction CTA and DSA were calculated on a per-patient and per-aneurysm basis.

RESULTS

according to the reference standard, 96 aneurysms were present in 81 patients and no aneurysm was found in 16 patients. The overall sensitivity, specificity, positive predictive value and negative predictive value of subtraction CTA on a per-aneurysm basis were 98.9, 100, 100 and 94.1%, respectively. DSA prospectively detected 88 aneurysms in 79 of 81 patients. On a per-aneurysm basis, the sensitivity, specificity, positive predictive value and negative predictive value of DSA were 91.7, 100, 100 and 66.7%, respectively.

CONCLUSION

the diagnostic accuracy of 64-section dual-energy subtraction CTA is promising in detection and characterization of intracranial aneurysms. In most cases, it may substitute for conventional DSA as the primary imaging method in the diagnostic work-up of intracranial aneurysms.

Three-dimensional CT study on the anatomy of vertebral artery at atlantoaxial and intracranial segment

BACKGROUND

The atlantoaxial and intracranial segments of vertebral artery (V(3-4)) are winding around their peripheral structures. Their panorama is not easy to be observed in surgery. CT angiography (CTA) shows some advantages in this aspect. So, the aim of this study is to reveal the three-dimensional (3D) anatomy related to V(3-4) and prepare ground for clinical diagnosis and treatment.

METHODS

Ninety-eight cases without the pathologies of V(3-4) were selected from the head-neck CTA examination. All the 3D images were formed with multiplanar reconstruction, volume rendering and volume rendering together with separating, fusing, opacifying and false-coloring. On the 3D images, the courses and branch of V(3-4) were observed and measured, as well as their peripheral venous vascular plexus (VVP).

RESULTS

V(3-4) with typical five curves was found in 85 cases and with variations in 13. The left V(3-4) is larger than right (P < 0.05). The branch shown on the 3D image is the posterior inferior cerebellar artery at V(4), at most two on either side. VVP are at the back of the atlantoaxial joints and around the V(3), each on either side. There is no significant difference in size and shape between left and right (P > 0.05).

CONCLUSIONS

The anatomy and variations of V(3-4) can be clearly and directly shown by 3DCTA. The understanding of vertebral artery and bony structures around there can provide anatomic basis for surgery and radiological diagnosis.

Contralateral far-lateral approach for clipping of a ruptured vertebral artery-posterior inferior cerebellar artery aneurysm

Numerous nuanced approaches have been used to access posterior inferior cerebellar artery (PICA) aneurysms for microsurgical clipping. The authors report the case of a patient with a right vertebral artery (VA)-PICA aneurysm that was reached via a contralateral far-lateral approach. The wide-necked saccular/fusiform aneurysm arose from the lateral aspect of the right V(4) segment just proximal to the PICA origin, anterior to the jugular tubercle at the level of the hypoglossal canal. Computed tomography angiograms demonstrated the size and configuration of the aneurysm, and 3D reconstructions revealed the tortuosity of the right VA, defining its location just left of the midline adjacent to the lower clivus. A contralateral far-lateral approach to VA-PICA aneurysms should be considered when aneurysms cross the midline. Computed tomography angiography with volume rendering and interactive software capabilities can help identify the relationship of such an aneurysm to an individual's particular skull base osseous anatomy and is paramount in selecting the optimal microsurgical approach.

Imaging anatomy and variation of vertebral artery and bone structure at craniocervical junction

The objective of this article is to display the vertebral artery and bone structure at the craniocervical junction (CJVA and C(0-1-2)) with three-dimensional CT angiography (3DCTA) and identify their anatomic features and variations. Eighty-eight subjects without pathology of vertebral artery (VA) and C(0-1-2) were selected from head-neck CTA examination. 3D images were formed with volume rendering (VR) and multiplanar reconstruction (MPR). On the 3D images, CJVA and C(0-1-2) were measured, and their variations were observed. CJVA goes along C(0-1-2) with five curves, of which three curves are visibly away from C(0-1-2), one is 0.0-8.3 mm away at the second curve with 0.0-11.2 mm in width, another is 0.0-9.2 mm away at the fourth with 2.8-14.8 mm and the other is 0.0-6.2 mm away at the fifth. Statistical comparisons show that there is no significant difference in the measurements between left and right, and that the curves become smaller and farther away from C(0-1-2) with the increase of age. CJVA is not equal in size, with the biggest in the fourth curve and the smallest in the fifth. Statistical comparison shows the left CJVA is larger than the right in the fifth curve. Variations were found on CJVA in 16 cases and on C(1) in 12 cases. The anatomy and variations of CJVA and C(0-1-2) are complicated. It is of vital significance to identify their anatomic features in clinical practice.

Computed tomographic angiography as an adjunct to digital subtraction angiography for the pre-operative assessment of cerebral aneurysms

Objectives:

Computerized tomographic angiography (CTA) has emerged as a valuable diagnostic tool for the management of patients with cerebrovascular disease. The use of CTA in lieu of, or as an adjunct to, conventional cerebral angiography in the management of cerebral aneurysms awaits further experience. In this study, we evaluated the role of CTA specifically for the pre-operative assessment and planning of cerebral aneurysm surgery.

Patients and Methods:

We reviewed the relevant neuroimaging of all patients treated at Dartmouth Hitchcock Medical Center between January, 2001 and December, 2004 with a diagnosis of cerebral aneurysm and diagnostic evaluation with both CTA and conventional digital subtraction angiography (DSA) using standard imaging protocols. 32 patients underwent both CTA and DSA during the study period for a total of 36 aneurysms. Images were independently re-assesed by two neurosurgeons for information valuable for pre-operative surgical planning.

Results:

In 26 of 36 aneurysms (72%), the CTA was felt to provide the best image quality in defining the morphology of the aneurysm. In 14 aneurysms (39%), CTA provided clinically valuable anatomic detail not demonstrated on DSA, largely due to better visualization of parent and perforating vessel relationships at the aneurysm neck. There were no instances where a lesion was seen on DSA but missed on CTA. The DSA was of most clinical value in determining flow dynamics, such as the arterial supply of an anterior communicating artery aneurysm and distal anterior cerebral branches via the two A1 segments.

Conclusion:

CTA with three-dimensional reconstructions is a valuable adjunct to the preoperative evaluation of cerebral aneurysms. We advocate routine use of CTA in all patients in whom surgical aneurysm repair is planned, even when DSA has already been performed.