Bithalamic hyperintensity on T2-weighted MR: vascular causes and evaluation with MR angiography

PURPOSE: To determine whether MR angiography can be used to differentiate between the two vascular causes of bithalamic hyperintensity on T2-weighted MR images: "top of the basilar" artery occlusion and deep cerebral vein thrombosis. METHODS: A retrospective review identified six patients with bithalamic T2 hyperintensity of vascular causes. MR angiography was performed in four patients, MR angiography and conventional angiography in one patient, and conventional angiography in one patient. Data pertaining to clinical presentation and hospital course were collected. MR angiographic techniques were multislab overlapping three-dimensional time-of-flight, 2-D time-of-flight, and 2-D phase-contrast. RESULTS: Three cases of top of the basilar artery occlusion and three cases of deep cerebral vein thrombosis were recognized. In all cases, T2 hyperintensity in a vascular distribution suggested cerebral occlusive disease. Infarction involving the thalami and basal ganglia was present in two cases of deep cerebral vein thrombosis. Infarction of the thalami, mesodiencephalic region, and cerebellar hemispheres was present in two cases of basilar artery occlusion. Bithalamic infarction alone was seen in one case of deep cerebral vein thrombosis and one case of basilar artery occlusion. In the five cases in which MR angiography was used, this technique accurately distinguished the vessels involved (arterial or venous). CONCLUSION: MR angiography is a useful adjunct to MR imaging in the evaluation of bithalamic T2 hyperintensity. It does help distinguish between the two vascular causes: top of basilar artery occlusion and deep cerebral vein thrombosis.     

Angiography in non-traumatic brain haematoma. An analysis of 100 cases

PURPOSE: The primary purpose of this project was to study the anatomical characteristics of intracerebral haematoma (ICH) in order to determine features that may negate the need for angiography in some patients. MATERIAL AND METHODS: The study was prospective and designed to investigate the underlying cause of non-traumatic ICH in 100 cases assessed by conventional angiography. Patients were excluded if there was a history of trauma or known pre-existing brain abnormality. All patients were examined with CT and angiography within 4 days of the ictus. RESULTS: Ruptured aneurysms or arteriovenous malformations (AVMs) were diagnosed on the initial angiogram in 49% of cases: 27 AVMs and 22 aneurysms. One case of superior sagittal sinus thrombosis was also detected. Vascular abnormalities were found most frequently in the under-40 age group and in cases in which subarachnoid haemorrhage, intraventricular haemorrhage or extracerebral haematoma accompanied the ICH. The temporal lobe was the most frequent anatomical location (37%). When a temporal lobe haematoma extended into the Sylvian fissure from the inferior pole of the temporal lobe or when it was associated with subarachnoid haemorrhage, structural abnormalities were found in over 90% of cases. CONCLUSIONS: There are groups of patients with ICH in whom the CT features are highly suggestive of AVM or aneurysm rupture. If the initial angiography is negative in these cases, careful follow up by repeat angiography and/or MR imaging is essential. However, potentially treatable abnormalities cannot be excluded with certainty by the distribution of the haematoma on CT alone, even if there is a history of pre-existing hypertension.     

Posterior inferior cerebellar artery aneurysm in the fourth ventricle

We report a patient with a ruptured aneurysm of the choroidal branch of the right posterior inferior cerebellar artery (PICA), lying in and causing an isolated haemorrhage in the fourth ventricle. MRI on the first day after bleeding revealed an abnormal vessel in the fourth ventricle, which was surrounded by a mass of intermediate signal on T1- and T2-weighted images. The aneurysm was clipped via partial splitting of the lower vermis and opening the inferior medullary velum. A postoperative angiogram confirmed complete obliteration of the aneurysm. With PICA aneurysms the rate of intraventricular haemorrhage is high and in most cases due to reflux of blood. If there is an isolated intraventricular haemorrhage, a peripheral PICA aneurysm, lying in or near the fourth ventricle, may be suspected.     

Herpes simplex type 2 infection in a cohort aged 21 years

We report a rare case of a ruptured aneurysm of the choroidal branch of the left posterior inferior cerebellar artery (PICA) located in the fourth ventricle. Digital subtraction angiography revealed this PICA aneurysm but the exact location remained unknown. The unique location in the fourth ventricle was subsequently shown by magnetic resonance imaging (MRI). The patient died and the final diagnosis was confirmed by autopsy. To our knowledge, this is one of the few reported cases of a PICA aneurysm in the fourth ventricle and the only one which was confirmed by the combination of MRI and autopsy.     

Functional radiology of the liver: magnetic resonance imaging

Magnetic Resonance (MR) images sensitive to the flowing blood are defined as images of MR angiography. Proton movement within a magnetic field modifies both the intensity and the phase of Nuclear Magnetic Resonance (NMR) signal; two techniques of MR angiography are thus distinguished: (TOF) the "time of flight" (intensity) and the "phase-contrast" (phase) technique. In the time of flight MR angiography the blood may appear as hypointense or hyperintense compared to stationary tissues. Blood hypointensity in vessels is due to the flow void phenomenon while hyperintensity is due to the phenomenon of flow-related enhancement. In phase contrast MR angiography, protons moving within a magnetic field modify their phase directly proportional to the displacement velocity and gradient intensity. Moreover, MRI allows noninvasive measurement of blood flow. Flow velocity is measured with TOF sequences or phase-contrast sequences. In TOF sequences quantitative measurement is performed with the bolus tracking procedure. In contrast-phase sequences the velocity is measured based on the extent of signal phase modification induced by the proton displacement velocity. The recent use of liver-specific contrast media supplies information on parenchymal liver function.     

Diagnostic and surgical management of spinal dural arteriovenous fistulas

OBJECTIVE: A retrospective review was conducted to compare magnetic resonance (MR) and conventional spinal angiographic images and to investigate the outcome of our treatment protocol for patients with spinal dural arteriovenous fistulas (DAVFs). MATERIALS AND METHODS: Nine patients with a diagnosis of DAVF based on clinical myelopathy and preoperative MR imaging (MRI) and MR angiography (MRA) findings were treated at our institution by the senior author (BAG). All nine patients initially presented with progressive myelopathy. Preoperative MRI revealed T2-weighted signal abnormalities in all patients, and MRA was diagnostic in all patients. Each patient underwent a laminectomy and ligation of the arterialized draining vein. Selective spinal angiograms were used to confirm the level of fistula immediately before the surgical procedure was performed and to document complete obliteration after clip ligation of the medullary draining vein. Follow-up MRI and MRA were performed approximately 2 months postoperatively. RESULTS: MRI T2-weighted signal hyperintensity improved after surgery in all nine patients. Postoperatively, progression of motor weakness and gait difficulty was halted and some improvement was observed in all patients. No patient was neurologically normal, however. To date, there has been no clinical or MRA evidence of recurrence in any patient. CONCLUSION: Preoperative MRA and intraoperative spinal x-ray angiography present as an effective combination for diagnosing and intraoperatively confirming DAVF. Both T1-weighted enhancement and T2-weighted signal hyperintensity on MR images improved after the obliteration of the DAVFs and correlated with clinical improvement in all nine patients. MRA provides adequate visualization and localization of spinal DAVFs and may serve as a useful noninvasive tool for diagnosing and following patients with spinal DAVFs in the future.     

Ligature carrier specifically designed for transvaginal sacrospinous colpopexy

The purpose of this paper is to clarify whether copper accumulation in hepatocellular carcinoma (HCC) is a cause of high intensity signal pattern on T1-weighted images (T1-WI) by comparing the histologically proven copper accumulation with MR images. Forty-five surgically resected HCCs were analyzed. Distribution patterns of divalent copper by a modified Timm's method on their maximum cut surfaces were compared with signal patterns on corresponding T1-WI. The degree of copper accumulation in tumor compared with surrounding liver tissue was higher in 6 lesions, equal in 17 lesions, and lower in 22 lesions. High intensity pattern on T1-WI were observed in 3 of 6 lesions (50%), 10 of 17 lesions (59%), and 10 of 22 lesions (45%). Distribution patterns of copper were not correlated with intensity patterns on T1-WI. We conclude that the paramagnetic effect of divalent copper accumulation in HCC is insufficient to influence the MRI.     

Detection of bioradicals by in vivo ESR spectrometry

BACKGROUND AND PURPOSE: In 1964, the first case of "de novo" aneurysm has been reported by Graf and Hamby. The risk of late formation of aneurysm is unknown. Some factors could influence risk: history of hypertension, oral contraceptives, cigarette smoking. We report a rare case of "de novo" aneurysm associated with Ehlers-Danlos syndrome. RESULTS: A 35-year-old female developed a subarachnoid hemorrhage (SAH). Angiography demonstrated 4 aneurysms. Five years before, she presented a SAH. At that time, four vessels angiography demonstrated only one PICA aneurysm. A Ehlers-Danlos syndrome was suspected, which was demonstrated on skin biopsies. CONCLUSION: At our knowledge, this is the first case of "de novo" aneurysm associated with a Ehlers-Danlos syndrome.     

The painful reality of street children

CT, MRI and contrast angiography of 20 patients with 21 developmental venous anomalies (DVAs), so-called venous angiomas, were compared with magnetic resonance angiography employing a two-dimensional time-of-flight technique (2D-MRA). MRA was diagnostic in 17 DVAs, when both the primary 2D slices and the maximum-intensity-projection images were read. Contrast angiography still provides the best visualization of both DVA components: dilated medullary veins and transcerebral draining vein; however, it is an invasive procedure and delivers no information about brain parenchyma. We regard MRI as necessary in cases with a suspected DVA because of the high rate of association with cavernomas: 33% in this study. Acute neurological symptoms were caused by haemorrhage from an associated cavernoma and not from the DVA in 4 such cases. Thus MRA combined with MRI obviates angiography in most cases and offers a noninvasive diagnostic strategy adequate for DVAs.     

Follow-up after patch aortoplasty for coarctation of aorta

BACKGROUND: Patch aortoplasty (PA) for coarctation of aorta (COA) can lead to aneurysm formation at the repair site. X-ray, echocardiogram and computed tomography are unreliable for diagnosis of this complication. OBJECTIVE: To evaluate prospectively patients with PA for COA by magnetic resonance imaging (MRI) to detect presence of aneurysm at the repair site. DESIGN: All patients who underwent PA at the authors' institution were identified. MRI was performed in transverse and long axis oblique views on all patients except those who had, or were going to have, aortic angiography for other reasons. Details of the surgical procedure were obtained from the hospital records. RESULTS: Of the 18 patients studied, 15 had MRI and three had aortic angiography. Age at PA ranged from one week to 13.3 years (mean 6.3 years). The interval from PA to MRI or angiography was 9.5 years (range four to 12.5). No aneurysm was detected in any patient. Recoarctation was diagnosed in two patients not previously suspected but discovered on MRI. At PA the intimal shelf causing coarctation was either not excised or only minimally trimmed in 14 of 15 instances. CONCLUSIONS: The incidence of late aneurysm formation following PA for COA is low in the authors' patients, possibly due to minimal intimal damage at repair, although these patients should be followed longer. MRI was useful for assessment of aneurysm and restenosis.     

Changes in the hippocampus induced by glucose in thiamin deficient rats detected by MRI

Using T2-weighted Magnetic Resonance Imaging (MRI) in a pyrithiamin-treated, thiamin deficient (TD) rat model of Wernicke's encephalopathy (WE), we have observed hyperintensity in the thalamus, hypothalamus, collicular bodies and hippocampus which was enhanced 40 min after a glucose load. Hyperintensity was not evident in these structures in thiamin replete rats receiving glucose nor was it enhanced in TD rats administered 2-deoxyglucose. Residual hyperintensity was still evident in the hippocampus as long as 30 days after thiamin administration and was increased by repeat glucose challenge at that time. These data indicate that the hippocampus is as vulnerable as the thalamus to some persistent pathological change when glucose is metabolised in a state of thiamin deficiency.     

Imaging methods in the diagnosis of acute cerebrovascular stroke

The authors emphasize the possibilities of some new imaging methods in the diagnosis of acute cerebrovascular attacks, i.e. methods used under local conditions: differentiation of intracranial haemorrhage in case of a haematoma in the area of a ruptured aneurysm, blood in the subarachnoidal space in subarachnoid haemorrhage. To differentiate a tumour decompensated by the vascular route. It is known that imaging by computed tomography. Imaging on the basis of magnetic resonance in the diagnosis of acute, subacute and chronic infarction has some specific features. It was revealed that also magnetic resonance angiography can be an asset, in particular when major vessels are affected. Classical intervention angiography still is useful in acute cerebrovascular attacks as well as in the diagnosis of cerebral death.     

Ruptured fusiform cerebral aneurysm in a neonate

An 11-day-old male infant presented with subarachnoid and intraventricular haemorrhage caused by a ruptured intracranial aneurysm. Magnetic resonance (MR) angiogram and digital subtraction angiography (DSA) revealed a fusiform aneurysm 10 mm in diameter supplied by the proximal segment of the anterior cerebral artery (A1), with both distal segments (A2) arising from the aneurysm. The right A1 was aplastic. There have been 13 previous case reports of neonatal cerebral artery aneurysms, but only 1 of these has been fusiform. None of the earlier reports has mentioned dysplastic segments or other anomalies of the circle of Willis.     

The usefulness of magnetic resonance angiography in surgery for intracranial aneurysms that have bled

BACKGROUND: Once it was confirmed that magnetic resonance imaging (MRI) including angiography (MRA) could demonstrate intracranial aneurysms, a study was set up to establish whether satisfactory images could be obtained to plan and execute early surgery on ruptured intracranial aneurysms without recourse to intra-arterial digital subtraction angiography (IA.DSA) in the acute phase of the illness. METHODS: All patients presenting with a subarachnoid haemorrhage (SAH) were considered for MR studies. The patient selection was based on whether they were considered fit enough to tolerate scanning and did not have a known contraindication. A standard protocol was used--a three-dimensional time-of-flight with T1 and T2-weighted sagittal and axial images. If an aneurysm was demonstrated and early surgery was undertaken they were entered into the study. RESULTS: Over a 25-month period, 122 patients were submitted for MR studies, these being selected from over 200 patients presenting with an SAH. Aneurysms were believed to be present in 55 patients who were clinically suitable for early surgery. There were 21 males and 34 females, with an age range of 23-79 years, a mean of 50.5 years. Sixty-three aneurysms in all were demonstrated and 55 of these were surgically dealt with. There were two false positives. CONCLUSION: MRI is the investigation of choice to plan surgery in those patients presenting with an SAH who, on clinical grounds, would be considered suitable for early surgery. The imaging is easily obtained, non-invasive, avoids radiation, and in view of the multiple images obtained is often superior to conventional DSA.     

Large distal anterior cerebral artery aneurysm associated with azygos anterior cerebral artery: case report

A 51-year-old woman presented with a distal anterior cerebral artery aneurysm (DACAA) manifesting as severe headache and monoparesis of the left lower limb. Computed tomography revealed subarachnoid hemorrhage in the interhemispheric fissure, bilateral sylvian fissures, and basal cistern, and a hematoma in the supracallosal region. Angiography showed a large aneurysm (23 x 18 mm) located on the distal end of the azygos anterior cerebral artery (azygos ACA) at the supracallosal portion. T2-weighted magnetic resonance imaging demonstrated the hematoma as a mixed intensity mass, compressing the corpus callosum downward, and the aneurysm as a flow void anterior to the hematoma. Unilateral frontoparietal parasagittal craniotomy was performed with a horse-shoe shaped incision. The aneurysm was clipped via the interhemispheric approach, and the hematoma was aspirated. Postoperative angiography showed disappearance of the aneurysm and intact azygos ACA. The patient was discharged with mild monoparesis, paresthesia of the left lower limb and diagnostic dyspraxia. DACAA almost always arises at or near the genu of the corpus callosum and is often associated with vascular anomaly. In the literature, 22 of 26 cases of large and giant DACAA were located at or near the genu, but only 3 cases, including ours, in the supracallosal area. 11 cases were associated with azygos ACA. Therefore, hemodynamic stress caused by vascular anomaly may be involved in the formation of large or giant DACAA in contrast with cases of normal DACAA.     

Etiology of immune stromal (interstitial) keratitis

BACKGROUND: Subarachnoid hemorrhage (SAH) with a spinal origin is a rare clinical entity. The most common source of SAH is an arteriovenous malformation. Only six cases of spinal hemangioblastomas causing SAH have been reported. CASE DESCRIPTION: This 48-year-old man had experienced severe headache 12 years earlier, which was diagnosed as SAH by computed tomography (CT) scan and lumbar puncture. However, cerebral angiography could not detect either aneurysm or arteriovenous malformation. Thereafter, he spent an uneventful life until he was incidentally diagnosed with a cervical tumor on magnetic resonance imaging (MRI) study for Meniere's disease. The tumor was situated at the cervicomedullary junction, and fed by the left vertebral artery. Histologic findings of the tumor showed features typical of hemangioblastoma. CONCLUSIONS: We describe a case of cervical spinal extramedullary hemangioblastoma with a past history of SAH. In our case, the SAH of 12 years ago perhaps occurred from the cervicomedullary junction hemangioblastoma. Since the etiology of SAH could not be detected at the first angiography, not only follow-up reangiography, but also MRI of the spinal cord and spinal angiography could have played an important role.     

Spontaneous occlusion of supraclinoid aneurysms after the creation of extra-intracranial bypasses using long grafts: report of two cases

OBJECTIVE: We describe two cases of giant supraclinoid aneurysms, treated by means of saphenous vein grafting between the external carotid artery and the middle cerebral artery, which unexpectedly spontaneously occluded. CLINICAL PRESENTATION: Two patients presented with subarachnoid hemorrhage and headache, respectively. In the first case, angiography showed an aneurysm of the right internal carotid artery (ICA), which had been treated by clipping. Repeat angiography showed a giant aneurysm of the right ICA, the formation of which was probably caused by sliding of the clip that had been applied during the previous operation. The patient was operated on again, but it was impossible to exclude the aneurysm because no clear neck could be identified. In the second case, magnetic resonance imaging and cerebral angiography showed a large, partially thrombosed aneurysm of the supraclinoid segment of the left ICA. TECHNIQUE: In view of the patients' ages and the statuses of compensatory circulation, each patient underwent cerebral revascularization with a long saphenous vein graft placed between one branch of the middle cerebral artery and the external carotid artery, in anticipation of subsequent endovascular treatment of the aneurysm and/or closure of the ICA in the neck. Postoperative angiography demonstrated spontaneous occlusion of the aneurysms. CONCLUSION: Thrombosis of an aneurysm may occur spontaneously or after explorative surgery. However, it should be remembered that spontaneous occlusion of an aneurysm may be induced or favored by hemodynamic vascular alterations that take place inside the aneurysm after a high-flow extra-intracranial bypass has been created.     

Embolization for ruptured superior mesenteric artery aneurysms

Superior mesenteric artery (SMA) aneurysms are very uncommon. They are difficult to detect until they rupture and cause hypovolaemic shock. We performed embolization in four cases of aneurysm of branches of the superior mesenteric artery, succeeding in three cases without the need for surgical treatment. In the first case, the aneurysm was excised because of migration of a microcoil into the left hepatic artery. It was not retrieved because sufficient blood flow to the liver was shown on angiography after migration and no ischaemic change of liver was detected on laparotomy. In the second case, the aneurysm arose from the anterior pancreaticoduodenal artery. In the third case, the patient had two SMA aneurysms; one had been resected at surgery, another was revealed on follow-up angiography and embolized with microcoils. The fourth patient had a jejunal artery aneurysm with extravasation; haemostasis was achieved by packing it. In all four cases, no major complications were observed in the clinical course after embolization. Microcoils were considered to be the desirable embolic material, in order to prevent post-therapeutic ischaemic change. Embolization should be the treatment of choice for SMA aneurysms, because it is less invasive and takes less time than surgical treatment.     

Aneurysms of the cerebral vessels and pneumococcal infection

Two cases of cerebral aneurysm rupture with repeat subarachnoidal haemorrhage are reported in patients with pneumococcal infection confirmed bacteriologically. It is concluded that in pathogenesis of the aneurysmal rupture in pneumococcal infection a significant role is played not only by pneumococcal tropism to the meninges, but also by affection of the endothelium and cerebral vascular membranes, hemostasis defects, arterial hypertension as manifestations of a general adaptation syndrome.     

Effects of heparin-induced non-esterified free fatty acid on minimal model-derived insulin sensitivity in individuals with varying degrees of glucose intolerance

We report a case of pineocytoma associated with an unusually large cyst. A 15-year-old boy was admitted with a complaint of intermittent headache. Neurological examination was normal except for bilateral papilledema. CT scan showed triventricular hydrocephalus and a large mass. A solid portion of the tumor in the pineal and retrothalamic areas was isodense, and contained massive calcification on CT. A huge cystic portion extended far into the infratentorial, supracellebellar area. On MR, the solid tumor showed isointensity on T1-WI and iso- to high intensity on T2-WI, and was enhanced by Gd-DTPA. After a ventriculo-peritoneal shunt, the tumor was partially removed through an occipital supratentorial approach. Histological examination revealed a pineocytoma with neuronal and astrocytic differentiations. Reviewing the literature, it is most unusual to find a pineocytoma associated with a huge cyst as was seen in this case.