Ruptured vertebral artery dissecting aneurysm associated with parent artery occlusion

A 63-year-old hypertensive man presented with vertebral artery (VA) dissection manifesting as subarachnoid hemorrhage located mainly in the posterior fossa. Left vertebral angiography on the day of hemorrhage showed complete occlusion of the left VA. Right vertebral angiography showed retrograde filling of the distal portion of the left VA and the left posterior inferior cerebellar artery, and a "double lumen"-like finding in the left VA. He was managed conservatively. Follow-up angiography on Day 29 showed spontaneous recanalization of the occlusive lesion and an almost normal arterial configuration. T2-weighted magnetic resonance (MR) imaging on Day 45 revealed multiple infarctions in the brainstem. T1-weighted MR imaging showed a high intensity area, suggestive of intramural hematoma, in the left VA. He was transferred to another hospital in a persistent vegetative state.     

Acute dissection of the descending aorta: noncommunicating versus communicating forms

BACKGROUND: Noncommunicating dissecting intramural hematoma is an aortic dissection variant, characterized by absent flow within the false lumen. Noncommunicating dissecting intramural hematoma is thought to be more stable than communicating dissection when beginning in the descending aorta. This study assessed clinical characteristics, anatomic characteristics, and 1-year outcomes in acute descending noncommunicating dissecting intramural hematoma versus communicating dissection. METHODS: Retrospective database review identified patients who underwent magnetic resonance or computed tomography imaging revealing acute descending noncommunicating dissecting intramural hematoma or communicating dissection. Comparisons of clinical and anatomic characteristics and 1-year outcomes were performed. RESULTS: Twenty-four noncommunicating dissecting intramural hematoma and 36 communicating dissection cases were identified. Patients with noncommunicating dissecting intramural hematoma were older (68.5 +/- 8.8 versus 61.8 +/- 11.6 years; p < 0.05). Although noncommunicating dissecting intramural hematoma often showed abdominal aorta extension (50%), the infrarenal level was spared. Communicating dissection characteristically extended beyond the diaphragm (89%), including into the infrarenal aorta (28%). There was no significant difference in rates of adverse clinical events for noncommunicating dissecting intramural hematoma versus communicating dissection (13% versus 30%; 0.10 > p > 0.05). By follow-up imaging (87% of population), aortic deterioration was more frequent in noncommunicating dissecting intramural hematoma versus communicating dissection cases (60% versus 15%; p < 0.005). CONCLUSIONS: Acute descending noncommunicating dissecting intramural hematoma and communicating dissection represent two variants, with differing clinical and anatomic characteristics, but comparable levels of 1-year morbidity.     

Dilated outer diameter of the dissected artery: acute bilateral anterior cerebral artery dissection evaluated by repeat magnetic resonance cisternography. Case report

A 42-year-old male patient presented with an anterior cerebral artery (ACA) dissection manifesting as sudden onset of severe headache. Initial computed tomography revealed faint subarachnoid hemorrhage in the frontal region. Initial angiography showed tapering stenosis at the A(2) segment of right ACA. The patient was admitted to our hospital and treated conservatively. Magnetic resonance (MR) imaging and angiography did not detect intramural hematoma, intimal flap, or double lumen at the stenotic right A(2) segment. The ACA dissection was difficult to confirm based on the findings on day 0. ACA dissection was confirmed by improvement of the right ACA stenosis on follow-up angiography on day 14. On the other hand, MR cisternography revealed a fusiform dilatation of the vascular outer contour at the right A(2) on day 0, which had resolved on day 14. Cerebral angiography and MR cisternography similarly suggested asymptomatic contralateral (left) A(2) dissection on day 14. Fusiform dilatation of the vascular outer contour at the affected segment on MR cisternography may be indicative of arterial dissection in the acute phase.     

Assessment of aortic dissection and hematoma

Aortic dissection and aortic intramural hematoma are highly lethal diseases occurring mostly in patients with arterial hypertension or Marfan syndrome. Transesophageal echocardiography (TEE) is the diagnostic imaging procedure of choice in the unstable patient. Hallmarks of dissection are the presence of an intimal membrane, or flap, dividing a true and a false lumen, entry and reentry tears, periaortic hematoma, pericardial effusion or tamponade, and aortic regurgitation in dissection of the ascending aorta. TEE allows detection of involvement of the ascending aorta, which places the patient in an extremely high-risk group and necessitates urgent operation. The accuracy of TEE is similar to computed tomography and magnetic resonance imaging, with the added benefit of being feasible at the bedside or in the operating room. Precautions have to be taken during TEE to avoid an abrupt rise in blood pressure. Aortic intramural hematoma is often a precursor of classic dissection or accompanies it and can also be diagnosed by TEE, although the diagnosis is frequently difficult.     

Serial neuroimaging of a growing thrombosed giant aneurysm of the distal anterior cerebral artery--case report

An 81-year-old female presented with a giant aneurysm of the distal anterior cerebral artery (A3) which grew from a small saccular aneurysm to a huge aneurysm within 36 months before manifesting as a mass lesion. The thrombosed portion of the aneurysm showed growth, whereas the aneurysmal cavity did not change in size. Computed tomography and magnetic resonance imaging showed new bleeding in the thrombosed portion. Hemorrhage into the thrombus and/or aneurysmal wall might have caused the aneurysmal growth. She refused surgery and was discharged with no deficits. Distal anterior cerebral artery aneurysm which shows neuroimaging signs of growth requires regular follow up as such lesions may become giant before manifesting clinical symptoms.     

Giant aneurysm of the pericallosal artery

A rare case of a giant aneurysm of the pericallosal artery, evaluated by computed tomography, magnetic resonance imaging, and angiography, is reported, and the other 7 cases in the literature are reviewed. Giant aneurysms are exceptional in the distal segments of the anterior cerebral arteries, and may simulate a callosal tumor or hematoma on computed tomographic scan. The clinical, radiological, surgical, and pathological findings of giant aneurysms of this location are discussed and the other reported cases are analyzed. The role of magnetic resonance imaging in diagnosing and characterizing giant aneurysms is stressed.     

Spontaneous occlusion of a dissecting aneurysm in the shape of "two dumplings on a skewer" at righ posterior inferior cerebellar artery (PICA): report of a case and neuroradiological findings

We present a case of a spontaneous dissecting aneurysm at the vertebrobasilar artery including the right PICA in a 44-year-old man, who suffered from headache, hiccup and ataxic gait. The arteriograms showed an irregular narrowing and dilatation in the right PICA and in the vertebrobasilar artery, and showed fusiform dilatations in the bilateral middle cerebral arteries. We observed intramural hematoma and true lumen at the right PICA dissecting aneurysm on T1-weighted images on magnetic resonance imaging (1.5T, MRI), and the intimal flap was enhanced on T1-weighted image after intravenous injection of Gd-DTPA. The shape of the intramural hematoma showed a unique "two dumplings on a skewer" appearance, and the intensity of its hematoma in the false lumen decreased in gradient from adventitia to intimal flap on T1-weighted image on MRI. The dissecting aneurysm of the PICA was occluded spontaneously 1 month later, and it caused cerebellar infarction. However, the patient has been left only with the symptom of slight trunkal ataxia. Various shapes of intramural hematomas on MRI have been reported by Kitanaka in association with intracranial vertebrobasilar dissections. We suggest that "two dumplings on a skewer" shape which corresponds to the flow void of the true lumen, accompanied by intramural hematoma and enhanced intimal flap, on contrast-enhanced T1-weighted image, should be regarded as a true "diagnostic sign" of a dissecting aneurysm.     

Multiple arterial fenestrations, multiple aneurysms, and an arteriovenous malformation in a patient with subarachnoid hemorrhage

We report the case of a 49-year-old, right-handed man with multiple vascular pathologies, including a fenestrated anterior communicating artery and middle cerebral artery, an aneurysm of the anterior communicating artery, multiple aneurysms of the middle cerebral artery, and an arteriovenous malformation. Diagnoses were made through computed tomography, cerebral angiography, magnetic resonance imaging, and intraoperative dissection. The lesions were managed surgically in stages with satisfactory results. Congenital and hemodynamic factors may have combined to manifest in the anomalies present in this unique case. We believe that no similar combination of vascular pathology has been reported previously.     

Cerebral infarction and fluid collection due to an enlarged dissecting aneurysm of the middle cerebral artery--case report

A 53-year-old man presented with cerebral infarction associated with a dissecting aneurysm of the left middle cerebral artery (MCA), with enlargement and fluid collection. Anticoagulant therapy was performed as the first stage treatment for cerebral infarction. Serial magnetic resonance imaging showed that the dissecting aneurysm had enlarged and fluid collection adjacent to the aneurysm had developed since the first admission. Surgery was performed to ligate the MCA proximal to the aneurysm. Intraoperative findings showed the branch of the MCA was obstructed by intramural hemorrhage of the aneurysm dome. Histological examination showed direct obstruction of the MCA branch artery by intramural hemorrhage of aneurysm dome had caused the cerebral infarction and the fluid collection surrounding the aneurysm resulted from minor leakage or exudation of intramural hemorrhage to the outer surface of the dissecting aneurysm.     

Recent advances in thoracic aortic surgery

Surgical treatment for thoracic aortic diseases has been challenging for cardiovascular surgeons. Advances in diagnostic modalities such as multidetector row computed tomography, magnetic resonance imaging, and transesophageal and epiaortic echocardiography provide precise information to determine the surgical strategy. The pathologic entity of acute aortic dissection has been clearly defined, although the terminology for penetrating aortic ulcer, intramural hematoma, and thrombosed aortic dissection remains controversial. The term "acute aortic syndrome" has been advocated for emergent treatment. Therapeutic advances in total aortic arch replacement have been remarkable, particularly in the field of brain protection. Selective antegrade cerebral perfusion and retrograde cerebral perfusion have been developed since the 1990s and refined mainly by Japanese surgeons. Endovascular aortic repair with stent grafting is the most recent emerging technology that encourages a more aggressive strategy for the treatment of high-risk patients with thoracic aortic pathology.     

Ischemic events due to intraoperative microemboli developing in the cerebral hemisphere contralateral to carotid endarterectomy in a patient with preoperative cerebral hemodynamic impairment

A 74-year-old man with a history of asymptomatic right internal carotid artery (ICA) occlusion experienced amaurosis fugax in the left eye. Angiography showed left cervical ICA stenosis in addition to right cervical ICA occlusion. The right anterior and middle cerebral artery (MCA) territories were perfused from the left ICA via the anterior communicating artery. Brain perfusion single-photon emission computed tomography revealed reduced cerebral blood flow and reduced cerebrovascular reactivity to acetazolamide only in the right cerebral hemisphere. The patient underwent left carotid endarterectomy (CEA). Transcranial Doppler monitoring showed microembolic signals in the left MCA during dissection of the left ICA, but intraoperative monitoring suggested absence of global hypoperfusion or ischemia in the bilateral cerebral hemispheres during left ICA clamping. Transient and slight motor weakness of the left upper extremity was noted on recovery from anesthesia. Diffusion-weighted magnetic resonance imaging demonstrated the development of new spotty ischemic lesions only in the right cerebral hemisphere. The present case suggests that intraoperative cerebral embolism causing postoperative neurological deficits can develop exclusively in the cerebral hemisphere contralateral to CEA if the hemisphere has preoperative hemodynamic impairment and collateral circulation via the anterior communicating artery from the ICA ipsilateral to CEA.     

Vertebrobasilar artery dissection presenting with simultaneous subarachnoid hemorrhage and brain stem infarction: case report

BACKGROUND: Intracranial dissecting aneurysms have been associated with subarachnoid hemorrhage (SAH) or cerebral ischemia. We encountered a patient presenting with simultaneous subarachnoid hemorrhage and brainstem infarction caused by a dissecting aneurysm of the vertebrobasilar artery, which was diagnosed by magnetic resonance imaging (MRI) but did not show abnormal findings on cerebral angiography. CASE DESCRIPTION: A 55-year-old man had sudden onset of headache and left abducens palsy. Computed tomography revealed a subarachnoid hemorrhage localized in the left prepontine cistern and the left cerebellomedullary fissure. Cerebral angiography showed neither a saccular aneurysm nor fusiform dilatation causing the subarachnoid hemorrhage. MRI demonstrated a small infarction in the left dorsal pons, and an intramural hematoma of the left vertebral artery and lower basilar artery. CONCLUSION: This is a rare case of a vertebrobasilar dissecting aneurysm that simultaneously caused both SAH and brain stem infarction. MRI should be performed in the acute phase of SAH of unknown origin to determine the possible coexistence of a dissecting aneurysm, as occurred in this case.     

A case with traumatic internal carotid artery dissection in which the extent of the pseudolumen was defined by MR angiography]

We report a 29-year-old male with traumatic internal carotid artery (ICA) dissection who presented with cerebral ischemia developed after removal of a left acute subdural hematoma and external decompression. CT scans 4 days after the operation showed infarctions of the distribution of the bilateral cerebral hemispheres. Cerebral angiography on the 11th hospital day demonstrated narrowing of the extracranial internal carotid artery at C1-C2 vertebral levels. Slight arterial dilatation and retention of the contrast medium were found just above the narrowing segment, which was suspected to be a pseudolumen. Three D time-of flight MRA showed an intramural hematoma corresponding to the narrowing on the angiography. Original axial MRA images showed that narrowing of the lumen was surrounded by a crescent hematoma and that two flow velocity areas were in the area distal to the narrowing. High flow seemed to be ordinary artery flow rate. The low flow area, including turbulent flow, led to the retention of contrast medium mimicking a pseudolumen. Precise MRA imaging will bring us an accurate diagnosis of extracranial carotid dissections.     

Spinal cord ischemia complicated with acute aortic dissection and intramural hematoma; report of two cases

Spinal cord ischemic injury is one of te most serious complications in patients with aortic dissection. We experienced 2 cases with severe upper back pain and paraplegia of the lower extremities as initial manifestations of acute DeBakey type IIIb aortic dissection (case 1) and aortic intramural hematoma (IMH) from ascending aorta to abdominal aorta (case 2). Paraplegia was permanent and spinal cord atrophy was proved at Th 9-10 by the magnetic resonance imaging (MRI) in case 1. The aortic IMH regressed rapidly and paraplegia was transient in case 2. The MRI obtained 18 days after the onset showed scattered small lesions within the spinal cord at Th 4-7.     

Spontaneous retroclival hematoma presenting as a thunderclap headache. Case report

An excruciating headache of instantaneous onset, or thunderclap headache, may be caused by a variety of serious disorders, including aneurysmal subarachnoid hemorrhage, cerebral venous sinus thrombosis, pituitary apoplexy, and carotid artery or vertebral artery dissection. The authors describe a patient with this type of headache who was found to have a spontaneous retroclival hematoma. A 49-year-old woman experienced an instantaneous excruciating headache. Results of computerized tomography (CT) scans of the head were normal, but on examination of the cerebrospinal fluid xanthochromia was found. Magnetic resonance (MR) imaging of the cervical spine revealed a retroclival hematoma. Three cerebral angiographic studies did not reveal the source of the hemorrhage and a repeated MR image demonstrated resolution of the hematoma. The patient made an uneventful recovery. Spontaneous retroclival hematoma is an exceedingly rare type of intracranial hemorrhage and may be associated with normal findings on CT scans. Spontaneous retroclival hematoma should be included in the differential diagnosis of thunderclap headache.     

Intraoperative assessment of aneurysm clipping using magnetic resonance angiography and diffusion-weighted imaging: technical case report

OBJECTIVE AND IMPORTANCE: To use intraoperative magnetic resonance imaging, including magnetic resonance angiography and diffusion-weighted imaging, to monitor the surgical treatment of a patient with an intracranial aneurysm. TECHNIQUE: Intraoperative imaging was performed with a ceiling-mounted, mobile, 1.5-T magnet (developed in collaboration with Innovative Magnetic Resonance Imaging Systems, Inc., Winnipeg, MB, Canada) that included high-performance 20-mT/m gradients. Pre- and postclipping, intraoperative, T1-weighted, angiographic and diffusion-weighted magnetic resonance images were obtained from a patient with an incidental, 8-mm, anterior communicating artery aneurysm. RESULTS: T1-weighted images demonstrated brain anatomic features, with visible shifts induced by surgery. Magnetic resonance angiography demonstrated the aneurysm and indicated that, after clipping, the A1 and A2 anterior cerebral artery branches were patent. Diffusion-weighted studies demonstrated no evidence of brain ischemia. CONCLUSION: For the first time, intraoperative magnetic resonance imaging has been used to monitor the surgical treatment of a patient with an intracranial aneurysm.     

Spontaneous dissecting aneurysms of the basilar artery presenting with a subarachnoid hemorrhage. Report of two cases

A spontaneous dissecting aneurysm of the basilar artery is a rare disorder, usually presenting with ischemia rather than a subarachnoid hemorrhage (SAH). Two cases are described of a dissecting aneurysm of the basilar artery presenting with an SAH. Vertebral angiography revealed a double lumen to the basilar artery. Magnetic resonance (MR) imaging detected the intramural hematoma. One patient was treated conservatively, and the other underwent operative intervention with wrapping of the aneurysm. The usefulness of MR imaging in the diagnosis and the treatment options are discussed.     

Dissecting aneurysm of the anterior temporal artery: case report

A 65-year-old woman presented a rare dissecting aneurysm of the anterior temporal artery (ATA) manifesting as headache. Computed tomography and magnetic resonance imaging revealed a mixed-density mass in the horizontal segment of the middle cerebral artery. Emergent angiography demonstrated aneurysmal dilatation and a thrombosed mass in the sylvian fissure. Infectious aneurysm was excluded. She underwent emergent surgery to reduce the risk of repeated infarction and hemorrhage. The distal side of the ATA manifested occlusive changes suggestive of arterial dissection. The proximal side of the ATA was ligated and the lesion was excised. Histological examination confirmed that the aneurysmal dilatation was attributable to arterial dissection due to disruption of the internal elastic lamina. Distal dissecting aneurysms may occur in the absence of infectious disease. We recommend that ruptured distal dissecting aneurysms be treated surgically in the acute stage immediately after detection.     

Growth of occult arteriovenous malformation after cerebral hemorrhage demonstrated by serial magnetic resonance imaging--case report

A 19-year-old male presented with sudden onset of right hemiparesis caused by left cerebral hemorrhage. Cerebral angiography demonstrated no vascular abnormality, and the hematoma was removed surgically. At operation, no abnormal vascular lesion was found in the brain adjoining the hematoma. Two years later, magnetic resonance (MR) imaging demonstrated a few foci of flow voids adjacent to the hematoma cavity. Four years after the hemorrhage, MR imaging showed more extensive flow-void abnormalities that indicated growth of an occult arteriovenous malformation (AVM). Cerebral angiography indicated a definite AVM supplied mainly by branches of the middle cerebral artery. Total resection of this lesion was performed. The histological diagnosis was typical AVM. Immunohistochemistry with vascular endothelial growth factor showed staining in the walls of the abnormal vessels. Serial MR imaging is very useful for the diagnosis and management of occult AVMs.     

Spontaneous improvement of idiopathic intracranial carotid artery dissection: a case report

We report a rare case of spontaneous intracranial carotid artery dissection presenting with multiple infarctions. A 65-year-old man became aware of transient visual disturbance in the right eye and headache. Magnetic resonance imaging (MRI) at a local neurosurgical clinic depicted fresh multiple infarctions of the right cerebral hemisphere along with severe right carotid artery stenosis and delayed cerebral blood flow on the right side. The patient was transferred to our hospital. Three-dimensional computed tomography (3D-CT) showed an intimal flap in the righ petrous internal carotid artery and we diagnosed spontaneous intracranial carotid artery dissection of the petrous portion. We started conservative therapy including anti-coagulant and antiplatelet drug and blood pressure control. Two weeks after admission, angiography, 3D-CT, MR angiography demonstrated that the dissection had improved and the patient was discharged without neurological deficit. In this case, 3D-CT was effective for the diagnosis of intracranial carotid artery dissection. We report this rare case along with a literature review of the clinical profile and related neuroimaging findings.