Incidence and prognosis of > or = 50% symptomatic vertebral or basilar artery stenosis: prospective population-based study.

The higher risk of early recurrent stroke after posterior circulation transient ischaemic attack or minor stroke versus after carotid territory events could be due to a greater prevalence of large artery stenosis, but there have been few imaging studies, and the prognostic significance of such stenoses is uncertain. Reliable data are necessary to determine the feasibility of trials of angioplasty and stenting and to inform imaging strategies. In the first-ever population-based study, we determined the prevalence of > or = 50% apparently symptomatic vertebral and basilar stenosis using contrast-enhanced MRA in consecutive patients, irrespective of age, presenting with posterior circulation transient ischaemic attack or minor ischaemic stroke in the Oxford Vascular Study and related this to the 90-day risk of recurrent transient ischaemic attack and stroke. For comparison, we also determined the prevalence of > or = 50% apparently symptomatic carotid stenosis on ultrasound imaging in consecutive patients with carotid territory events. Of 538 consecutive patients, 141/151 (93%) had posterior circulation events and had vertebral and basilar imaging, of whom 37 (26.2%) had > or = 50% vertebral and basilar stenosis, compared with 41 (11.5%) patients with > or = 50% ipsilateral carotid stenosis in 357/387 (92%) patients with carotid events who had carotid imaging (OR = 2.74; 95% CI = 1.67-4.51; P = 0.002). Presence of > or = 50% vertebral and basilar stenosis was unrelated to age, sex or vascular risk factors and, in contrast to > or = 50% carotid stenosis was not associated with evidence of coronary/peripheral atherosclerosis. In patients with posterior circulation events, > or = 50% vertebral and basilar stenosis was associated multiple transient ischaemic attacks at presentation (22% versus 3%; OR = 9.29; 95% CI = 2.31-37.27; P < 0.001) and with a significantly higher 90-day risk of recurrent events (OR = 3.2; 95% CI = 1.4-7.0; P = 0.006), reaching 22% for stroke and 46% for transient ischaemic attack and stroke. The prevalence of > or = 50% vertebral and basilar stenosis in posterior circulation transient ischaemic attack or minor stroke is greater than the prevalence of > or = 50% carotid stenosis in carotid territory events, and is associated with multiple transient ischaemic attacks at presentation and a high early risk of recurrent stroke. Trials of interventional treatment are therefore likely to be feasible, but more data are required on the long-term risk of stroke on best medical treatment.

Symptomatic, radiological and pathological involvement of the hypothalamus in neuromyelitis optica.

This study describes a young girl who presented with involuntary weight loss, spontaneous vomiting and behavioural change. Imaging confirmed hypothalamic and brainstem involvement. Routine investigations (including cerebrospinal fluid analysis and neuromyelitis optica IgG) were unhelpful. Biopsy of the hypothalamic lesion implicated an aggressive inflammatory aetiology. There was a response to conventional immunosuppression, while a further relapse responded to plasma exchange. She died 21 months after presentation. Postmortem examination was highly suggestive of neuromyelitis optica, which was subsequently confirmed following the identification of aquaporin 4 antibodies.

Venoplasty and stenting of a jugular foramen meningioma.

The authors describe a novel approach to relieving major venous sinus stenosis at the level of the jugular bulb caused by a petrous meningioma. A balloon-expandable renovascular stent was deployed via a jugular approach to restore venous outflow and thus reduce visual and vestibulocochlear symptoms. Endovascular balloon venoplasty and stenting may assess and restore cranial outflow in veins compressed by soft tumours in anatomical locations challenging to surgical resection, even in the absence of intracranial hypertension.

White matter changes in Leber's hereditary optic neuropathy: MRI findings.

Leber's hereditary optic neuropathy is a mitochondrial disorder causing bilateral optic nerve degeneration. It is sometimes associated with clinical signs of multiple sclerosis. We report MRI findings in two patients with LHON-MS and comment on possible distinguishing features of this disease entity.

13C-breath tests: current state of the art and future directions.

13C-breath tests provide a non-invasive diagnostic method with high patient acceptance. In vivo, human and also bacterial enzyme activities, organ functions and transport processes can be assessed semiquantitatively using breath tests. As the samples can directly be analysed using non-dispersive isotope selective infrared spectrometers or sent to analytical centres by normal mail breath tests can be easily performed also in primary care settings. The 13C-urea breath test which detects a Helicobacter pylori infection of the stomach is the most prominent application of stable isotopes. Determination of gastric emptying using test meals labelled with 13C-octanoic or 13C-acetic acid provide reliable results compared to scintigraphy. The clinical use of 13C-breath tests for the diagnosis of exocrine pancreatic insufficiency is still limited due to expensive substrates and long test periods with many samples. However, the quantification of liver function using hepatically metabolised 13C-substrates is clinically helpful in special indications. The stable isotope technique presents an elegant, non-invasive diagnostic tool promising further options of clinical applications. This review is aimed at providing an overview on the relevant clinical applications of 13C-breath tests.

Progressive multifocal leukoencephalopathy: value of diffusion-weighted and contrast-enhanced magnetic resonance imaging for diagnosis and treatment control.

Progressive multifocal leukoencephalopathy (PML) is caused by the replication of JC virus in oligodendrocytes of immunocompromised patients. Diagnosis usually relies on the polymerase chain reaction (PCR)-based demonstration of JC virus DNA in the cerebrospinal fluid. As previous reports have suggested that some patients may benefit from antiviral therapy, non-invasive early diagnosis is highly desirable. Repetitive magnetic resonance imaging (MRI) examinations (two to nine) were obtained in seven patients (aged 40-67 years, six males, one female) with classical clinical and imaging findings of PML. Five patients had underlying hematological disorders and two acquired immune deficiency syndrome. PCR of the cerebrospinal fluid (CSF) specimen was positive for JC virus DNA in six patients. MRI sequences included T2-, T1- and diffusion-weighted (DW) images in all patients and diffusion-tensor imaging (DTI) in four cases. DTI was once performed at 3T, in the remaining patients at 1.5T. All patients received antiviral treatment with cidofovir in addition to the treatment of the underlying disorder. MRI showed areas of T2 hyperintensity with involvement of the subcortical U-fibers and restricted diffusion in all patients. Areas of diffusion abnormality correlated with disease progress. Contrast enhancement was encountered once after successful treatment and heralded clinical remission with virus elimination from the CSF. Hence, MRI including DW and contrast-enhanced images may be used to evaluate disease activity. Contrast enhancement may indicate an inflammatory response and thus herald immunologic virus elimination.

MRI features of primary central nervous system lymphomas at presentation.

Pretreatment MRI examinations of 40 immunologically competent patients with primary CNS lymphoma (PCNSL) were evaluated (24 men, 16 women, median age 63 years). Seventy lesions were found (mean size: 19.9 mm). The number of lesions ranged from one (n = 25) to six (n = 1). The most frequent locations were the cerebral hemispheres (n = 22), the corpus callosum (n = 11), and the basal ganglia (n = 11). Cerebellar manifestations were found in 10 patients. Ocular (n = 2) and medullary cord (n = 1) manifestations were rare. Contrast enhancement was encountered in all lesions. Although 39 patients had lesions adjacent to the CSF space, leptomeningeal spread was only present in five patients. Necrosis was seen in two lesions only. Edema was extensive in 24 patients, moderate in 11 patients, and absent in five patients. Contrast-enhancing lesions in contact with the subarachnoid space and without necrosis are characteristic of PCNSL.

Molecular imaging: Bridging the gap between neuroradiology and neurohistology.

Historically, in vivo imaging methods have largely relied on imaging gross anatomy. More recently it has become possible to depict biological processes at the cellular and molecular level. These new research methods use magnetic resonance imaging (MRI), positron emission tomography (PET), near-infrared optical imaging, scintigraphy, and autoradiography in vivo and in vitro. Of primary interest is the development of methods using MRI and PET with which the progress of gene therapy in glioblastoma (herpes simplex virus-thymidine kinase) and Parkinson's disease can be monitored and graphically displayed. The distribution of serotonin receptors in the human brain and the duration of serotonin-receptor antagonist binding can be assessed by PET. With PET, it is possible to localize neurofibrillary tangles (NFTs) and beta-amyloid senile plaques (APs) in the brains of living Alzheimer disease (AD) patients. MR tracking of transplanted oligodendrocyte progenitors is feasible for determining the extent of remyelinization in myelin-deficient rats. Stroke therapy in adult rats with subventricular zone cells can be monitored by MRI. Transgene expression (beta-galactosidase, tyrosinase, engineered transferrin receptor) can also be visualized using MRI. Macrophages can be marked with certain iron-containing contrast agents which, through accumulation at the margins of glioblastomas, ameliorate the visual demarcation in MRI. The use of near-infrared optical imaging techniques to visualize matrix-metalloproteinases and cathepsin B can improve the assessment of tumor aggressiveness and angiogenesis-inhibitory therapy. Apoptosis could be detected using near-infrared optical imaging representation of caspase 3 activity and annexin B. This review demonstrates the need for neurohistological research if further progress is to be made in the emerging but burgeoning field of molecular imaging.

Carotid artery dissections presenting as isolated posterior cerebral artery infarctions.

A spontaneous dissection of the carotid artery is a well-known cause of cerebral infarction, mostly due to an embolus from the affected vessel segment. For haemodynamic and anatomical reasons the territories of the middle and anterior cerebral arteries are usually involved. We report two cases of carotid artery dissections resulting in infarctions exclusively in the territory of the posterior cerebral artery. The underlying anatomical conditions were a fetal origin of the posterior cerebral artery and an embolic supra-ophthalmic occlusion of the internal carotid artery. To our knowledge similar cases have not previously been documented.

Ocular manifestation of primary nervous system lymphoma: what can be expected from imaging?

Primary ocular lymphoma, which affects the posterior parts of the eye, is an ocular manifestation of primary central nervous system lymphoma (PCNSL). It used to be the ocular disease with the shortest time of survival, even worse than ocular melanoma. Death ensues by CNS dissemination. Unfortunately, ocular lymphoma may be the initial manifestation of PCNSL and diagnosis is frequently difficult, even if vitreal biopsy is performed. Therefore, it should be determined whether cross sectional imaging may be helpful in detection and differential diagnosis of ocular lymphoma. MRI of seven patients (female = 6, male = 1, median age 62 years) with biopsy proven ocular lymphoma were retrieved from the files of our hospital and of a multicenter PCNSL study. In four patients, ocular lymphoma was the first manifestation of PCNSL, in three a cerebral lesion had occurred in the first place. Progression to cerebral lymphoma was seen in three of the four patients with initial eye manifestation. Imaging was performed using a dedicated thin section protocol in four patients. An intraocular abnormality was found in four cases, always in T1-weighted images after contrast injection. Differential diagnosis from uveitis or ocular melanoma was not possible by imaging alone. The examination was falsely negative in the remaining three patients.Hence, imaging has a low sensitivity for ocular lymphoma and does not facilitate differential diagnosis against uveitis or ocular melanoma.

Ultrasonography and contrast-enhanced MRA in ICA-stenosis: is conventional angiography obsolete?

BACKGROUND: The standard techniques for the screening and staging of internal carotid artery (ICA) stenosis are Doppler (continuous wave) and Duplex sonography. For the imaging of ICA occlusive disease, magnetic resonance angiography (MRA) is replacing digital subtraction angiography (DSA). The purpose of this observational study was to assess whether contrast enhanced MRA (CE-MRA) combined with ultrasound provided sufficient information for the planning of surgical treatment. METHODS: CE-MRA was performed in 195 patients (mean age 67.5 years) with sonographic evidence of severe ICA stenosis. The MRA examination protocol contained a heavily T1-weighted contrast bolus enhanced 3D-gradient echo sequence. The degree of stenosis was estimated retrospectively by two experienced neuroradiologists who were blinded to the sonographic findings. RESULTS: The consistency of MRA and ultrasound was sufficient to plan thrombendarterectomy in 182/195 patients. The estimations of the degree of stenosis were congruent between MRA and ultrasound in 91% of 197 vessels with high-degree carotid artery stenosis. CE-MRA evaluation had a high interobserver agreement. In 3 cases ultrasound examination diagnosed a filiform ICA stenosis which was not visible with MRA. In all these cases, DSA and the intraoperative findings revealed very short (1-2 mm), high-grade, excentric stenosis. CE-MRA correctly detected patency in 5 patients with high-grade and low-flow carotid artery stenosis, which had been regarded as occluded by ultrasound. Conversely with, in CE-MRA two occluded vessels were falsely considered as open. CONCLUSION: The combination of sonography and CE-MRA is a powerful tool for the non-invasive presurgical evaluation of the carotid arteries. DSA should be reserved for selected cases.

A prospective trial of mechanical physiotherapy for lumbar disk prolapse.

Fifty consecutive patients with neuroradiologically confirmed lumbar disk prolapse, who responded to the first five daily physiotherapy sessions with pain centralization, were prospectively treated with mechanical physiotherapy (McKenzie). At a median follow-up of 55 weeks, there were high rates of patient satisfaction, recovery from neurological deficits, and employment, and a low rate of surgical interventions. Mechanical physiotherapy is thus a useful diagnostic tool and an effective treatment strategy for many patients with lumbar disk disease.

Giant cavernoma of the brain stem: value of delayed MR imaging after contrast injection.

Cavernous angiomas are vascular malformations composed of slowly perfused, sinusoidal vessels which can be located in any part of the central nervous system. Whereas diagnosis is mostly straightforward in typical cases, some lesions may present in unusual locations or with unusual imaging characteristics. Because of the slow perfusion, contrast enhancement is not regarded as a characteristic imaging feature of cavernomas. We report a large brain stem cavernoma with signs of recent bleeding, in which the differential diagnosis against other mass lesions was facilitated by the demonstration of slow, but intense, contrast enhancement on MRI 1 h after contrast injection. We conclude that contrast enhancement in delayed images may contribute to a safe diagnosis of cavernous haemangiomas and should be performed in atypical cases.

Spontaneous occlusion of a cerebral arteriovenous malformation: angiography and MR imaging follow-up and review of the literature.

We present the angiographic and MR imaging course of a 62-year-old man with a right parietal high-flow arteriovenous malformation (AVM), which was diagnosed because of seizures. A spontaneous, complete, and asymptomatic occlusion of the AVM was confirmed by a second angiography 3 months later. The possible mechanisms leading to the occlusion are discussed, and a brief review of the literature is given.

Epidural spinal infection. Variability of clinical and magnetic resonance imaging findings.

STUDY DESIGN: This study evaluates the magnetic resonance characteristics of spinal epidural abscesses and their associated disc space infections. OBJECTIVES: The results were correlated with history, clinical, and laboratory findings to provide guidelines for early and appropriate diagnosis of epidural spinal infections. SUMMARY OF BACKGROUND DATA: Imaging signs of spinal infections have been reported before, but not with special attention to early clinical and imaging findings. METHODS: Thirteen patients (10 men, 3 women; age range, 32-64 years) with progressive sensorimotor deficit were studied. All patients had a neurologic examination after admission and a magnetic resonance imaging scan done within the first 48 hours. In all cases, T1-weighted images before and after administration of gadolinium were obtained. T2-weighted images were acquired in eight cases as well. Ten patients subsequently underwent open surgery; in three cases, a percutaneous biopsy and drainage was performed. RESULTS: Cervical discitis was found in five patients, and thoracic discitis was seen in another five cases. Three patients had an epidural infection without a concomitant discitis. Neurologic and clinical findings varied considerably. Despite clinical signs of spinal cord involvement, a spinal cord lesion was demonstrated only once. Signal change in T2-weighted images may be the first sign of disc space infection. Because a neurologic deficit may occur before any change is visible, follow-up examinations may be required if epidural infection is suspected on clinical grounds. CONCLUSIONS: Magnetic resonance imaging is the appropriate method for diagnostic work-up of progressive neurologic deficit resulting from epidural infection.

[Enhanced MR-angiography (CE-MRA) of the supraaortic arteries: dose reduction with a contrast agent of high relaxivity (Gd-BOPTA)]. / Kontrastmittelverstärkte MR-Angiographie (CE-MRA) der supraaortalen Arterien: Dosisreduktion bei einem Kontrastmittel hoher Relaxivität (Gd-BOPTA).

PURPOSE: Reducing the amount of contrast medium in contrast-enhanced MR-angiography (CE-MRA) of the cervical vessels could lead to considerable cost reduction. This study investigates whether the amount of contrast medium possessing high relaxivity can be reduced without loss of diagnostic information. MATERIALS AND METHODS: In a prospective study the supraaortic vessels of 40 patients were examined on a 1.5 T MR-system using 10 or 20 ml Gd-BOPTA (MultiHance). The examinations were evaluated by measurement of the signal increase in the common carotid arteries in 38 patients. Furthermore, CE-MRA was rated by two independent observers, who were blinded to the amount of contrast medium and degree of stenosis. Rating criteria were quality of arterial contrast and image impression. RESULTS: Signal increase in the carotid artery was identical for 10 and 20 ml Gd-BOPTA in 12 patients with optimal bolus timing (10 ml: 454 +/- 58; 20 ml: 458 +/- 63). Signal intensities were significantly lower for 10 ml when bolus timing was suboptimal (281 +/- 80 vs 353 +/- 65; p < 0.02). The quality of the CE-MRA using 10 and 20 ml Gd- BOPTA was rated as identical by the observers, and the amount of contrast medium used could not be deduced from the images. CONCLUSION: Image quality and signal values of the carotid arteries did not differ in CE-MRA performed with either 10 ml or 20 ml Gd-BOPTA (MultiHance) as long as the examination is adequate. Thus, cost reduction can be achieved with a reduced standard dose of 10 ml Gd-BOPTA without loss of diagnostic information.

Experimental autoimmune encephalomyelitis (EAE): lesion visualization on a 3 Tesla clinical whole-body system after intraperitoneal contrast injection.

PURPOSE: To investigate the intravital visibility of CNS lesions in rats with experimental autoimmune encephalomyelitis (EAE), the animal correlate of multiple sclerosis, using a 3-Tesla (T) whole-body MR system. MATERIALS AND METHODS: Three healthy Dark Agouti (DA) rats and 16 DA rats with clinical signs of EAE were examined on a 3T whole body-system using a normal wrist coil. In total, 25 examinations were preformed using T2- and T1-weigthed images in transverse and sagittal orientation with a slice thickness of 2 mm or 1 mm (voxel size up to 0.2 x 0.2 x 1 mm). Sedation was achieved by intraperitoneal injection of ketamine and xylazine. In addition, T1-weighted images were obtained after the instillation of 1.0 ml of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) (0.5 mmol/ml) into the peritoneal cavity. RESULTS: T2- and T1-weighted images of the brain and spinal cord with high spatial and contrast resolution could be obtained in all animals. The anatomical details of the olfactory bulb glomeruli, cerebellum foliae, ventricles and corpus callosum were clearly visible. The EAE lesions presented as hyperintense areas in T2-weighted images and could be demonstrated in all clinically affected animals by MRI and histologically verified. In total, the 16 affected rats had 28 cerebral and 2 spinal cord lesions (range 1 to 4, median 2). Contrast enhancement was noted in 12 animals and ranked as severe in ten and moderate in two cases. No adverse effects were noted due to sedation or intraperitoneal contrast injection. CONCLUSIONS: The intravital demonstration of cerebral and spinal cord EAE lesions in rats is possible on a 3T whole-body MR scanner using a normal wrist coil. Intraperitoneal injection of ketamine/xylazine and contrast agent is an easy, safe and effective procedure in rats.

[Contrast enhanced MR-angiography (CE-MRA): do contrast media with higher T1 relaxation improve imaging of carotid stenoses?]. / Kontrastangehobene MR-Angiographie (CE-MRA): Verbessern Kontrastmittel mit höherer T1-Relaxivität die Darstellung von Karotisstenosen?

PURPOSE: CE-MRA is a powerful tool for the non-invasive evaluation of carotid artery occlusive disease. However, due to certain drawbacks, it has not completely replaced DSA. The purpose of this study was to evaluate if Gd-BOPTA, a contrast agent with high T1 relaxivity, can increase the diagnostic accuracy of CE-MRA. MATERIAL AND METHODS: The CE-MRA examinations of 54 consecutive patients were evaluated by two experienced radiologists, independently. The examinations of 27 patients were contrasted either with 20 ml Gd-BOPTA or with 20 ml Gd-DTPA. The reviewers were blinded to the contrast agent chosen and to the ultrasound results. They rated the overall image quality and the degree of the ICA stenoses. RESULTS: For the estimation of the degree of the ICA stenoses there was a high interrater validity. In comparison to the ultrasound findings, 6 of 50 high-degree stenoses were underestimated as moderate stenoses. In one of seven sonographically occluded vessels, MRA revealed residual patency in the vessel lumen. It was not possible to identify the contrast agent that was taken for a study. Subjective estimation of the image quality (arterial contrast of the ICA, contrast of the other vessels, and general impression) did not significantly change with the contrast agent employed. CONCLUSION: The diagnostic accuracy of CE-MRA for the evaluation of internal carotid artery stenoses is not improved by Gd-BOPTA if identical volumina of contrast media are applied. The potential of this contrast agent can be the reduction of the amount of contrast without loss of diagnostic information. Further studies are necessary.