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Imaging occupies an important role in the investigation of dementia and neurodegenerative disease. The role of imaging in prion disease used to be one of exclusion of other conditions. Over the past decade, the non‐invasive nature of MRI, the improved range of magnetic resonance sequences and the availability of clinical and neuropathological correlation have led to a more prominent position of MRI and its inclusion in the diagnostic criteria for variant Creutzfeldt–Jakob disease. As experience of imaging in human prion disease increases, patterns of change related to strain and genotype may improve the diagnostic potential of imaging in the future, may reduce the need for more invasive testing and prove useful in future therapeutic trials. This paper reviews the current knowledge of imaging appearances in human prion disease.

A 31 year old HIV infected woman developed neuropsychiatric problems soon after starting highly active antiretroviral therapy (HAART). Despite modifying and subsequently stopping HAART her condition progressively worsened. Cranial magnetic resonance imaging revealed multiple areas of abnormal signal suggestive of either a vasculitis or demyelination.

Magnetic resonance imaging (MRI) is often divided into structural MRI and functional MRI (fMRI). The former is a widely used imaging technique in research as well as in clinical practice. This review describes the more important developments in structural MRI in recent years, including high resolution imaging, T2 relaxation measurement, T2*-weighted imaging, T1 relaxation measurement, magnetisation transfer imaging, and diffusion imaging. The principles underlying these techniques, as well as their use in research and in clinical practice, will be discussed.

Interstitial photodynamic therapy (IPDT) is a technique for applying photodynamic therapy (PDT) to internal tumours using light delivered via fibres inserted percutaneously. This phase I-II study assessed the safety and efficacy of IPDT for patients with persistent or recurrent head and neck cancer unsuitable for further treatment with surgery, radiotherapy or chemotherapy, recruited for 'last hope' salvage treatment. Patients were sensitised with 0.15 mg kg(-1) mTHPC (meso-tetrahydroxyphenyl chlorin) 4 days prior to light delivery from fibres inserted directly into the target tumour (20 J per site at 652 nm) under image guidance. In all, 45 patients were treated. Nine achieved a complete response. Five are alive and free of disease 10-60 months later. Symptomatic relief (mainly for bleeding, pain or tumour debulking) was achieved in a further 24. The median survival (Kaplan-Meier) was 16 months for the 33 responders, but only 2 months for the 12 nonresponders. The only serious complication was a carotid blow out 2 weeks after PDT. No loss of function was detected in nerves encased by treated tumours. Interstitial photodynamic therapy provides worthwhile palliation with few complications and occasional long-term survivors for otherwise untreatable advanced head and neck cancers. It is a treatment option worth adding to those available to integrated head and neck oncology teams.

Recent advances in magnetic resonance techniques make it possible to image physiological parameters such as molecular diffusion, tissue perfusion and cortical activation. These techniques greatly contribute to the early detection and to the understanding of the pathophysiological evolution and recovery from ischaemic stroke.

White matter (WM) abnormalities are frequently seen on brain MRI of HIV positive (HIV+) patients. We aimed to determine the prevalence of unexplained WM abnormalities and their associations with HIV disease and cardiovascular risk factors. We conducted a retrospective, cross-sectional study of brain MRI of HIV+ patients conducted between 2004 and 2009 at our center. Clinical and laboratory data were compiled, and images were independently reviewed for WM lesions. Images were obtained from 254 patients: 70% male, 53% white, 40% black, mean age 42 years, median current CD4 count 240 cells/mm(3), and 41% not taking antiretroviral therapy (ART). Hyperintense WM lesions were present in 161 patients (63.4%): 89 scans (35.0%) showed diffuse WM signal abnormality (DWMSA), 61 (24.0%) were consistent with small vessel disease (SVD, graded by Fazekas' scale), and 37 (14.6%) showed large asymmetrical focal WM lesions. SVD changes were associated with age and cardiovascular risk factors, and while cerebral SVD may be related to HIV infection, the MRI findings were not associated with HIV-related factors. The only risk factor for DWMSA was black race, and no correlation with cardiovascular risk factors, CD4 count, or clinical presentation was identified. DWMSA are therefore of uncertain neurological significance in HIV+ patients and could represent more than one clinicopathological entity.

Objective To evaluate the impact of immune recovery induced by highly active antiretroviral therapy (HAART) on the survival of AIDS patients with primary central nervous system lymphoma (PCNSL). Methods In a multicentric retrospective analysis, 29 HIV-infected patients with histologically confirmed PCNSL were identified. To evaluate median survival, Kaplan-Meier statistics were used. To explore the effects of different variables on survival, a Weibull accelerated failure time regression analysis was performed. Results Median age at manifestation of PCNSL was 39.1 years and median CD4 cell count was 11 x 10(6) cells/l. Seventy per cent of the patients had had a prior AIDS-defining illness. Cranial radiation (CR) was given to 12 out of 29 patients. Six patients were treated with HAART. Survival time of these patients and of the patients treated with CR alone differed significantly from those receiving neither CR nor HAART (median Kaplan-Meier survival estimate: 1093, 132, and 33 days, respectively). In the multivariate regression model, HAART and CR were identified as the only variables independently associated with prolonged survival. HAART versus no HAART and CR versus no CR increased the time to event by a factor of 6.1 (95% confidence interval, 2.4-16.0; P = 0.0002) and 3.1 (95% confidence interval, 1.5-6.3; P = 0.002), respectively. Four out of six patients on HAART showed a marked immune recovery and survived for more than 1.5 years, with two patients still alive. Conclusion Data from this cohort indicate that immune recovery induced by HAART leads to dramatic improvement in survival of patients with AIDS-associated PCNSL. These findings may have important implications for future treatment strategies.

Problems of clinical management of neurovascular diseases are very complex. This is caused by the chronic character of the diseases, a long history of symptoms and diverse treatments. If patients are to benefit from treatment, then treatment decisions have to rely on reliable and accurate knowledge of the natural history of the disease and the various treatments. Recent developments in statistical methodology and experience from electronic patient records are used to establish an information infrastructure based on a centralized register. A protocol to collect data on neurovascular diseases with technical as well as logistical aspects of implementing a database for neurovascular diseases are described. The database is designed as a co-operative tool of audit and research available to co-operating centres. When a database is linked to a systematic patient follow-up, it can be used to study prognosis. Careful analysis of patient outcome is valuable for decision-making.

The goal of this study was to develop a robust and simple technique for processing of cranial CT angiograms (CTA) in the clinical setting. The method described in this paper involves segmentation of the bone, then dilation of the skull by adding three or four layers of voxels. This dilated skull is subtracted from the vessels object on a voxel-by-voxel basis, allowing segmentation and subsequent display of the vessels only. For evaluation of the technique, three groups of operators processed one CTA, and the quality of the 3D views obtained and the times taken were compared. One group was given training by an expert and a "recipe" for guidance, the second was given only the "recipe," and the third group consisted of expert operators. All operators were able to produce good or acceptable shaded-surface displays when compared with digital subtraction angiography, within 10 min for experienced users, an average of 17 min for trained operators and 26 min for those using only the recipe sheet. Using a simple scoring system for the appearance of feeding vessels and draining veins, no significant differences were found between the three levels of training and experience. This technique simplifies the processing of CTAs and is quick enough to make such examinations part of a routine clinical service.

Conventional time-of-flight (TOF) MR angiography (MRA) in carotid artery stenosis relies on flow-related enhancement to produce signal from vascular structures. Intravoxel phase dispersion, due to vortices, causes loss of signal and is the reason for the tendency to overestimate the degree of stenosis. In contrast-enhanced MRA, intravascular signal is mainly dependent on T1 shortening of the blood. We compared first-pass contrast-enhanced MRA (contrast-enhanced 3D gradient echo, ce3D GRE) and contrast-enhanced 2D TOF (ce2D TOF) sequences with an unenhanced 2D TOF in 13 patients with carotid artery stenosis, assessing delineation of the carotid bifurcation, enhancement of veins and grade of stenosis. The contrast-enhanced techniques produced more morphological detail, the ce3D GRE being superior to the ce2D TOF. Four carotid arteries were reclassified into lesser stenosis categories using the ce3D GRE technique. However, seven carotid arteries (27 %) were rated as nondiagnostic on the ce3D GRE, mainly due to masking of the carotid bifurcation by veins. The latter can be avoided by decreasing the acquisition time; on our 1.5-T system we could achieve a minimum time of 23 s per 3D GRE. Further reduction of acquisition time would be necessary to incorporate this method into clinical routine, requiring higher-performance gradients, which are not available in many UK hospitals.

There have been important advances in stroke imaging, including CT perfusion imaging, xenon-CT, CT angiography, MR diffusion imaging, MR perfusion imaging, MR angiography and haemorrhage-sensitive gradient echo MR sequences. The technical principles and clinical applications of these methods are explained. An emphasis is made on the diagnosis of hyperacute cerebral ischaemia and issues surrounding the differentiation of reversible from irreversible ischaemic damage with modern imaging modalities, which has implications for thrombolytic therapy. This is followed by an overview of the role of imaging in patients with chronic stroke and transient ischaemic attack. In these patients, the diagnostic contribution of MRI in detecting the underlying pathology and the assessment of cerebrovascular reserve with perfusion imaging from an important part in the secondary prevention of stroke.

Using both an experimental model and clinical cases, we looked at the artefact produced by Aesculap titanium-alloy aneurysm clips on MRA. Experimentally, the volume affected by artefact was 50 % less when the clip was imaged lying parallel to the main ferromagnetic field than when lying perpendicular to it. Clinically, MRA was prospectively compared with digital subtraction angiography (DSA) in nine patients who had undergone aneurysm clipping. One patient with a non-diagnostic MRA due to movement artefact was excluded. In all other cases there was an area of signal loss surrounding the clips, obscuring the immediately adjacent vessel segments. There was good demonstration of the adjacent bifurcations in five cases and the contralateral circulation was seen well in all patients. In three cases in which the adjacent bifurcations were not seen, considerable vasospasm was suggested by MRA and confirmed with DSA. In one patient an unclipped contralateral ophthalmic artery aneurysm was identified using both modalities. In this series there were no adverse events relating to clips in either static or time-varying magnetic fields.

Aim To determine the frequency, microbiological diversity and radiological patterns of central nervous system (CNS) infection following allogeneic bone marrow transplantation (BMT). Patients and methods Two neuroradiologists retrospectively reviewed the computed tomography (CT) and magnetic resonance imaging (MRI) examinations of a large cohort of bone marrow recipients. The radiological findings were correlated with clinical, microbiological and pathological data. Results During an 8-year period 406 patients underwent allogeneic BMT; a total of 11 infections of the CNS were diagnosed in nine patients [sino-orbital aspergillosis (3), cerebral aspergillosis (2), pseudomonas (1), listeria (1), human herpes virus-6 (1), herpes zoster (1), toxoplasmosis (1) and progressive multifocal leucoencephalopathy (1)]. The radiological abnormalities could be divided into one or more of the following pathological entities: (i) focal lesions, (ii) invasive sinusitis, (iii) cerebral infarction, (iv) demyelination, (v) encephalitis and (vi) meningitis/hydrocephalus. Conclusions Approximately 2% of bone marrow recipients developed an infection of the CNS. The spectrum of infection changed over time and was related to predictable deficits in host immunity. The radiological appearances were diverse and corresponded to several different pathological processes.

Background: The use of protease inhibitors in the treatment of HIV-1 infection is associated with the new onset of diabetes mellitus, hyperlipidaemia and lipodystrophy. It is unclear whether these findings are coincidental or whether they reflect a causative effect of protease inhibitors. Objective: To evaluate the effect of treatment with protease inhibitors on insulin sensitivity, oral glucose tolerance and serum lipids in HIV-infected patients in order to determine whether treatment with protease inhibitors can cause peripheral insulin resistance. Design: Cross-sectional controlled study in HIV-infected patients treated with protease inhibitors to assess insulin sensitivity, oral glucose tolerance and changes in serum lipids. Methods: Sixty-seven patients treated with protease inhibitors, 13 therapy-naive patients and 18 HIV-negative control subjects were tested for insulin sensitivity (intravenous insulin tolerance test). In a subgroup of 24 treated patients, oral glucose tolerance was determined. Serum lipids prior to and under treatment with protease inhibitors were compared. Results: Patients on protease inhibitors had a significantly decreased insulin sensitivity when compared with therapy-naive patients (median, 75 and 156 μmol/l/min, respectively; P < 0.001). All treated patients with impaired (n = 4) or diabetic (n = 9) oral glucose tolerance, and four out of 11 patients with normal glucose tolerance showed peripheral insulin resistance; all therapy-naive patients had normal insulin sensitivity. Treatment with protease inhibitors led to a significant increase in total triglycerides and cholesterol in the 67 treated patients (median increase, 113 and 37 mg/ml, respectively). Conclusion: Treatment with protease inhibitors is associated with peripheral insulin resistance, leading to impaired or diabetic oral glucose tolerance in some of the patients, and with hyperlipidaemia. Overall, there is a large variation in the severity and clinical presentation of protease inhibitor-associated metabolic side-effects.

We describe two patients who presented with seizures and in whom imaging studies showed extra-axial disease which was simulating meningioma en-plaque. The diagnosis of neurosarcoidosis was obtained by meningeal biopsy. The clinical and MRI features of neurosarcoidosis presenting as an extra-axial mass lesion are reviewed. In cases in which clinical or radiological features place the diagnosis of meningioma in doubt, frozen section biopsy is advocated to avoid unwarranted excision of a lesion caused by sarcoidosis.

Imaging plays an important role in the diagnosis and management of dementia. This review covers the imaging features of the most common dementing illnesses: Alzheimer's disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB) and frontotemporal lobar degeneration (FTLD). It describes typical findings on structural neuroimaging and discusses functional and molecular imaging techniques such as FDG PET, amyloid PET, magnetic resonance (MR) perfusion imaging, diffusion tensor imaging (DTI) and functional MR imaging (fMRI).

Item does not contain fulltext BACKGROUND: Findings from randomised trials have shown a higher early risk of stroke after carotid artery stenting than after carotid endarterectomy. We assessed whether white-matter lesions affect the perioperative risk of stroke in patients treated with carotid artery stenting versus carotid endarterectomy. METHODS: Patients with symptomatic carotid artery stenosis included in the International Carotid Stenting Study (ICSS) were randomly allocated to receive carotid artery stenting or carotid endarterectomy. Copies of baseline brain imaging were analysed by two investigators, who were masked to treatment, for the severity of white-matter lesions using the age-related white-matter changes (ARWMC) score. Randomisation was done with a computer-generated sequence (1:1). Patients were divided into two groups using the median ARWMC. We analysed the risk of stroke within 30 days of revascularisation using a per-protocol analysis. ICSS is registered with controlled-trials.com, number ISRCTN 25337470. FINDINGS: 1036 patients (536 randomly allocated to carotid artery stenting, 500 to carotid endarterectomy) had baseline imaging available. Median ARWMC score was 7, and patients were dichotomised into those with a score of 7 or more and those with a score of less than 7. In patients treated with carotid artery stenting, those with an ARWMC score of 7 or more had an increased risk of stroke compared with those with a score of less than 7 (HR for any stroke 2.76, 95% CI 1.17-6.51; p=0.021; HR for non-disabling stroke 3.00, 1.10-8.36; p=0.031), but we did not see a similar association in patients treated with carotid endarterectomy (HR for any stroke 1.18, 0.40-3.55; p=0.76; HR for disabling or fatal stroke 1.41, 0.38-5.26; p=0.607). Carotid artery stenting was associated with a higher risk of stroke compared with carotid endarterectomy in patients with an ARWMC score of 7 or more (HR for any stroke 2.98, 1.29-6.93; p=0.011; HR for non-disabling stroke 6.34, 1.45-27.71; p=0.014), but there was no risk difference in patients with an ARWMC score of less than 7. INTERPRETATION: The presence of white-matter lesions on brain imaging should be taken into account when selecting patients for carotid revascularisation. Carotid artery stenting should be avoided in patients with more extensive white-matter lesions, but might be an acceptable alternative to carotid endarterectomy in patients with less extensive lesions. FUNDING: Medical Research Council, the Stroke Association, Sanofi-Synthelabo, the European Union Research Framework Programme 5.

IMPORTANCE: Prion diseases represent the archetype of brain diseases caused by protein misfolding, with the most common subtype being sporadic Creutzfeldt-Jakob disease (sCJD), a rapidly progressive dementia. Diffusion-weighted imaging (DWI) has emerged as the most sensitive magnetic resonance imaging (MRI) sequence for the diagnosis of sCJD, but few studies have assessed the evolution of MRI signal as the disease progresses. OBJECTIVES: To assess the natural history of the MRI signal abnormalities on DWI in sCJD to improve our understanding of the pathogenesis and to investigate the potential of DWI as a biomarker of disease progression, with histopathological correlation. DESIGN, SETTING, AND PARTICIPANTS: Gray matter involvement on DWI was assessed among 37 patients with sCJD in 26 cortical and 5 subcortical subdivisions per hemisphere using a semiquantitative scoring system of 0 to 2 at baseline and follow-up. A total brain score was calculated as the summed scores in the individual regions. In 7 patients, serial mean diffusivity measurements were obtained. Age at baseline MRI, disease duration, atrophy, codon 129 methionine valine polymorphism, Medical Research Council Rating Scale score, and histopathological findings were documented. The study setting was the National Prion Clinic, London, England. All participants had a probable or definite diagnosis of sCJD and had at least 2 MRI studies performed during the course of their illness. The study dates were October 1, 2008 to April 1, 2012. The dates of our analysis were January 19 to April 20, 2012. MAIN OUTCOMES AND MEASURES: Correlation of regional and total brain scores with disease duration. RESULTS: Among the 37 patients with sCJD in this study there was a significant increase in the number of regions demonstrating signal abnormality during the study period, with 59 of 62 regions showing increased signal intensity (SI) at follow-up, most substantially in the caudate and putamen (P

Background and Purpose— Transient focal neurological episodes (TFNE) are recognized in cerebral amyloid angiopathy (CAA) and may herald a high risk of intracerebral hemorrhage (ICH). We aimed to determine their prevalence, clinical neuroimaging spectrum, and future ICH risk. Methods— This was a multicenter retrospective cohort study of 172 CAA patients. Clinical, imaging, and follow-up data were collected. We classified TFNE into: predominantly positive symptoms (“aura-like” spreading paraesthesias/positive visual phenomena or limb jerking) and predominantly negative symptoms (“transient ischemic attack–like” sudden-onset limb weakness, dysphasia, or visual loss). We pooled our results with all published cases identified in a systematic review. Results— In our multicenter cohort, 25 patients (14.5%; 95% confidence interval, 9.6%–20.7%) had TFNE. Positive and negative symptoms were equally common (52% vs 48%, respectively). The commonest neuroimaging features were leukoaraiosis (84%), lobar ICH (76%), multiple lobar cerebral microbleeds (58%), and superficial cortical siderosis/convexity subarachnoid hemorrhage (54%). The CAA patients with TFNE more often had superficial cortical siderosis/convexity subarachnoid hemorrhage (but not other magnetic resonance imaging features) compared with those without TFNE (50% vs 19%; P =0.001). Over a median period of 14 months, 50% of TFNE patients had symptomatic lobar ICH. The meta-analysis showed a risk of symptomatic ICH after TFNE of 24.5% (95% confidence interval, 15.8%–36.9%) at 8 weeks, related neither to clinical features nor to previous symptomatic ICH. Conclusions— TFNE are common in CAA, include both positive and negative neurological symptoms, and may be caused by superficial cortical siderosis/convexity subarachnoid hemorrhage. TFNE predict a high early risk of symptomatic ICH (which may be amenable to prevention). Blood-sensitive magnetic resonance imaging sequences are important in the investigation of such episodes.

Cerebral microbleeds (CMBs) have emerged as an important new imaging manifestation of sporadic cerebral small vessel diseases – mainly hypertensive arteriopathy and cerebral amyloid angiopathy – which are highly prevalent in the elderly and have a critical role in vascular cognitive impairment and dementia. With the development of MRI techniques that are exquisitely sensitive to the products of bleeding, including T2*-weighted gradient-recalled echo (T2*-GRE) and susceptibility-weighted imaging (SWI), CMBs have been detected in ever-increasing numbers of patients, including those with vascular cognitive impairment and dementia, as well as in population-based samples of healthy elderly people. Our increased ability to image CMBs and hence to see the development and progression of cerebral small vessel disease raises many clinical and pathophysiological questions about the mechanisms, diagnosis and monitoring of cognitive impairment. In order to tackle these questions, it is important to be able to reliably detect, define and map CMBs in the brains of elderly people. In this review, we consider radiological detection methods, criteria for defining CMBs (including a practical approach to the identification of CMB “mimics”), and the use of standardised rating scales. We also briefly discuss the potential for automatically detecting and quantitatively mapping CMBs in future.

Technical difficulties in the deployment of a Wallstent biliary endo-prosthesis may be encountered in situations where increased friction forces interfere with the smooth withdrawal of its covering membrane. Examples of such situations are stenting of left-sided and very tight strictures and deployment of two or more stents lying parallel to or overlapping each other. We describe a new technique using an 8F peel-away introducer sheath, which reduces the resistance caused by friction during the release of an endoprosth-esis. The technique has the additional advantage of allowing easy advancing or removal of a partially deployed stent. This technique was successfully and safely used in 35 complex stenting procedures, which were carried out in 25 patients with mostly hilar strictures. Only two significant complications occurred (one haemobilia and one septicaemia), unrelated to the use of the sheath.

Subclinical acute ischaemic lesions on brain magnetic resonance imaging have recently been described in spontaneous intracerebral haemorrhage, and may be important to understand pathophysiology and guide treatment. The underlying mechanisms are uncertain. We tested the hypothesis that ischaemic lesions are related to magnetic resonance imaging markers of the severity and type of small-vessel disease (hypertensive arteriopathy or cerebral amyloid angiopathy) in a multicentre, cross-sectional study. We studied consecutive patients with intracerebral haemorrhage from four specialist stroke centres, and age-matched stroke service referrals without intracerebral haemorrhage. Acute ischaemic lesions were assessed on magnetic resonance imaging (

Although HIV-associated multicentric Castleman disease (HIV-MCD) is not classified as an AIDS-defining illness, mortality is high and progression to lymphoma occurs frequently. At present, there is no widely accepted recommendation for the treatment of HIV-MCD. In this retrospective (1998-2010), multicentric analysis of 52 histologically proven cases, outcome was analyzed with respect to the use of different MCD therapies and potential prognostic factors. After a mean follow-up of 2.26 years, 19 of 52 patients died. Median estimated overall survival (OS) was 6.2 years. Potential risk factors, such as older age, previous AIDS, or lower CD4 T cells had no impact on OS. Treatment was heterogeneous, consisting of cytostatic and/or antiviral agents, rituximab, or combinations of these modalities. There were marked differences in the outcome when patients were grouped according to MCD treatment. Patients receiving rituximab-based regimens had higher complete remission rates than patients receiving chemotherapy only. The mean estimated OS in patients receiving rituximab alone or in combination with cytostatic agents was not reached, compared with 5.1 years (P = .03). Clinical outcome and overall survival of HIV-MCD have markedly improved with rituximab-based therapies, considering rituximab-based therapies (with or without cytostatic agents) to be among the preferred first-line options in patients with HIV-MCD.

A 50-year-old secretary presented with a 23 year history of forgetfulness and left-sided deafness following chemotherapy for Hodgkin’s lymphoma, complicated by disseminated tuberculosis and varicella zoster virus (VZV). MRI revealed carotid and vertebro-basilar dolichoectasia, and multiple small deep infarcts including a left ventral cochlear nucleus infarct resulting in memory impairment and left …

We report two patients with meningitis due to spirochaetal infection, both of whom showed diffusely enhancing meninges around the brain and spinal cord. In addition, there was enhancement of the cerebrospinal fluid after intravenous administration of Gd-DTPA.

Objective: Brain microbleeds on gradient-recalled echo (GRE) T2*-weighted MRI may be a useful biomarker for bleeding-prone small vessel diseases, with potential relevance for diagnosis, prognosis (especially for antithrombotic-related bleeding risk), and understanding mechanisms of symptoms, including cognitive impairment. To address these questions, it is necessary to reliably measure their presence and distribution in the brain. We designed and systematically validated the Microbleed Anatomical Rating Scale (MARS). We measured intrarater and interrater agreement for presence, number, and anatomical distribution of microbleeds using MARS across different MRI sequences and levels of observer experience. Methods: We studied a population of 301 unselected consecutive patients admitted to our stroke unit using 2 GRE T2*-weighted MRI sequences (echo time [TE] 40 and 26 ms). Two independent raters with different MRI rating expertise identified, counted, and anatomically categorized microbleeds. Results: At TE = 40 ms, agreement for microbleed presence in any brain location was good to very good (intrarater κ = 0.85 [95% confidence interval (CI) 0.77–0.93]; interrater κ = 0.68 [95% CI 0.58–0.78]). Good to very good agreement was reached for the presence of microbleeds in each anatomical region and in individual cerebral lobes. Intrarater and interrater reliability for the number of microbleeds was excellent (intraclass correlation coefficient [ICC] = 0.98 [95% CI 0.97–0.99] and ICC = 0.93 [0.91–0.94]). Very good interrater reliability was obtained at TE = 26 ms (κ = 0.87 [95% CI 0.61–1]) for definite microbleeds in any location. Conclusion: The Microbleed Anatomical Rating Scale has good intrarater and interrater reliability for the presence of definite microbleeds in all brain locations when applied to different MRI sequences and levels of observer experience.

To prospectively compare tumor volume, relative cerebral blood volume (rCBV), and apparent diffusion coefficient (ADC) and short-term changes of these parameters as predictors of time to malignant transformation and time to death in patients with low-grade gliomas (LGGs).Patients gave written informed consent for this institutional ethics committee-approved study. Patients with histologically proved LGGs underwent conventional, perfusion-weighted, and diffusion-weighted magnetic resonance (MR) imaging at study entry and at 6 months. At both time points, tumor volume, maximum rCBV, and ADC histogram measures were calculated. Patient follow-up consisted of MR imaging every 6 months and clinical examinations. To investigate the association between MR imaging variables and time to progression and time to death, a Cox regression curve was applied at study entry and at 6 months. The models were corrected for age, sex, and histologic findings.Thirty-four patients (22 men, 12 women; mean age, 42 years) with histologically proved LGGs (eight oligodendrogliomas, 20 astrocytomas, and six oligoastrocytomas) were followed up clinically and radiologically for a median of 2.6 years (range, 0.4-5.5 years). Tumor growth over the course of 6 months was the best predictor of time to transformation, independent of rCBV, diffusion histogram parameters, age, sex, and histologic findings. When only single-time-point measurements were compared, tumor volume helped predict outcome best and was the only independent predictor of time to death (P.02).Six-month tumor growth helps predict outcome in patients with LGG better than parameters derived from perfusion- or diffusion-weighed MR imaging. Tumor growth can readily be calculated from volume measurements on images acquired with standard MR imaging protocols and may well prove most useful among various MR imaging findings in clinical practice.

This article focuses on pathologic processes affecting the optic nerve, optic nerve/sheath complex, and chiasm. Pathology of the visual pathways posterior to the chiasm is beyond the scope of this article and is discussed only briefly.

We present a registration-based approach to model growth of glioma tumours seen in serial magnetic resonance imaging. Two state-of-the-art intensity-based non-rigid registration methods are investigated for their ability to compensate for the mass effect of the tumour. Both methods perform well and volume change estimates correlate well with manual delineation. However the complex structural and functional changes in glioma cannot be fully resolved by intensity-based methods due to the profound changes in morphology and appearance associated with glioma progression.

The main goal of this study is to use image registration techniques to combine functional and structural information from different MR-derived images (ADC and rCBV maps, contrast enhanced T1-weighted MR images) in patients diagnosed with brain gliomas. This is a particularly challenging registration problem due to the diverse image characteristics and to the inconsistency between structural and functional image features. Specific registration protocols have been designed, including the selection of critical parameters, for the alignment of the multi-modal information. In addition, we have developed a visual assessment protocol to evaluate the accuracy of registration results obtained with the proposed methods. Preliminary results suggest that misregistration errors are below the functional image resolutions, thus achieving sub-voxel accuracy

We describe a case of human African trypanosomiasis with a number of unusual features. The clinical presentation was subacute, but the infection was shown to be due to Trypanosoma brucei rhodesiense. The infection relapsed twice following treatment and the patient developed a melarsoprol-associated encephalopathy. Magnetic resonance imaging (MRI) findings were suggestive of microhaemorrhages, well described in autopsy studies of encephalopathy but never before shown on MRI. The patient survived severe encephalopathy with a locked-in syndrome. Our decision to provide ongoing life support may be useful to physicians treating similar cases in a setting where intensive care facilities are available.

Background: Progressive multifocal leukoencephalopathy (PML) was reported to have developed in three patients treated with natalizumab. We conducted an evaluation to determine whether PML had developed in any other treated patients. Methods: We invited patients who had participated in clinical trials in which they received recent or long-term treatment with natalizumab for multiple sclerosis, Crohn's disease, or rheumatoid arthritis to participate. The clinical history, physical examination, brain magnetic resonance imaging (MRI), and testing of cerebrospinal fluid for JC virus DNA were used by an expert panel to evaluate patients for PML. We estimated the risk of PML in patients who completed at least a clinical examination for PML or had an MRI. Results: Of 3417 patients who had recently received natalizumab while participating in clinical trials, 3116 (91 percent) who were exposed to a mean of 17.9 monthly doses underwent evaluation for PML. Of these, 44 patients were referred to the expert panel because of clinical findings of possible PML, abnormalities on MRI, or a high plasma viral load of JC virus. No patient had detectable JC virus DNA in the cerebrospinal fluid. PML was ruled out in 43 of the 44 patients, but it could not be ruled out in one patient who had multiple sclerosis and progression of neurologic disease because data on cerebrospinal fluid testing and follow-up MRI were not available. Only the three previously reported cases of PML were confirmed (1.0 per 1000 treated patients; 95 percent confidence interval, 0.2 to 2.8 per 1000). Conclusions: A detailed review of possible cases of PML in patients exposed to natalizumab found no new cases and suggested a risk of PML of roughly 1 in 1000 patients treated with natalizumab for a mean of 17.9 months. The risk associated with longer treatment is not known.

In patients with stroke, gradient-echo MRI commonly detects microbleeds, indicating small artery disease with increased risk of macroscopic intracranial bleeding. Antithrombotic treatments are frequently prescribed after TIA and stroke, but there have been no previous studies of microbleeds in TIA. Because microbleeds may predict the hemorrhagic risk of antithrombotic treatments, we studied the prevalence of microbleeds, risk factors, and pathophysiologic mechanisms in patients with ischemic stroke and TIA.One hundred twenty-nine consecutive patients with ischemic stroke or TIA were studied with MRI including T2, fluid-attenuated inversion recovery, and gradient-echo MRI sequences. Blinded observers counted microbleeds and graded white matter T2 hyperintensities throughout the brain. TIA patients with previous ischemic stroke were excluded.Sixty-seven percent of patients had ischemic stroke; 33% had TIA. Microbleeds were found in 23% of ischemic stroke patients but only 2% of TIA patients (p0.001). There were no significant differences in conventional risk factors or the severity of white matter disease on T2 MRI between stroke and TIA patients. Patients with microbleeds were more often hypertensive (81 vs 59%; p = 0.04) and had more severe MRI white matter disease on T2 MRI (p = 0.003).Microbleeds are common in ischemic stroke but rare in TIA, an observation not explained by differences in vascular risk factors or severity of white matter disease seen on T2 MRI. This finding has implications for the safety of antithrombotic therapy and clinical trial design in the two groups. Microbleeds may also be a new marker for severe microvascular pathology with increased risk of permanent cerebral infarction.

Pathological changes on diffusion-weighted MR scans had been described in hemiplegic migraine and perfusion changes had been demonstrated in typical migraine aura with radio-isotope studies and, more recently, MR perfusion imaging. However, there is relatively little knowledge of the pathophysiology of long-lasting migraine aura and its possibly variant phenotype, visual snow. Our aim was to investigate with advanced MR techniques whether patients with long-lasting visual disturbance showed regional alterations in cerebral water diffusion and perfusion. We have studied four patients using MR perfusion and MR diffusion imaging. Two patients had typical visual aura and two had a primary persistent visual disturbance (visual snow phenomenon). All patients had normal conventional structural MR imaging. MR diffusion-weighted images were acquired with a b-value of up to 1000 s/mm2. From the diffusion weighted images we generated maps of apparent diffusion coefficient (ADC), which were inspected visually and used for ADC measurements of predefined regions of interest, which included the visual, frontal, insular and temporal cortices. MR perfusion imaging was performed using a bolus tracking technique with dynamic susceptibility-weighted images. Colour coded maps of relative cerebral blood volume, mean transit time and bolus arrival time were generated, as well as time-signal intensity curves over the anterior, middle and posterior cerebral artery territories. The maps of the ADC and above perfusion parameters appeared symmetrical in all patients with no evidence of decreased water diffusion or cerebral perfusion in the occipital regions, or elsewhere. There was no statistically significant difference between the ADC measurements of the primary visual cortices and other cortical regions. Our findings suggest that regional changes in cerebral water diffusion and perfusion do not play an important part in the pathophysiology of persistent migraine aura or primary persistent visual disturbance.

Summary: We report the case of malignant oligodendroglioma in a 36-year-old man who underwent diffusion-weighted, perfusion-weighted, and volumetric MR imaging before and after PCV (procarbazine, CCNU, vincristine) chemotherapy. The tumor regions exhibiting a low apparent diffusion coefficient and increased relative cerebral blood volume showed a marked response to chemotherapy and dramatic decrease in volume, whereas the remaining tumor regions showed little change. Diffusion-weighted and perfusion-weighted MR imaging may be helpful in predicting chemosensitivity of glial tumors.

This is an overview of diseases presenting with visual impairment, which aims to provide an understanding of the anatomy and pathology of the visual pathways. It discusses the relevant clinical background and neuroimaging findings on CT and standard and advanced MRI of diseases affecting the globe; optic nerve/sheath complex; optic chiasm, tract and radiation; and visual cortex. The overview covers common tumours, trauma, inflammatory and vascular pathology, and conditions such as benign intracranial hypertension and posterior reversible leukoencephalopathy syndrome.

Economy class syndrome was first reported in 1988 and refers to an association between air travel and venous thromboembolism.1 Recently, three cases of stroke in young adults without risk factors other than a patent foramen ovale have been reported, presumably the result of paradoxical embolism.2 We now present an unusual case of medial medullary infarction caused by vertebral artery dissection associated with abnormal neck posture during a long haul flight—another health related reason to travel first class. A 56 year old right handed insurance broker on a 7K hour economy class long haul flight returning to the United Kingdom fell asleep with his head uncomfortably twisted to the right. On waking he noticed pain in the left side of his neck and paraesthesia in the right arm. The episode resolved after 15 minutes, but recurred with a right hemiparesis affecting the arm and leg. He smoked 40 cigarettes a day and drank 24 units of alcohol a week. There was no significant past medical history and no family history of vascular disease. On examination, conscious level, cognition, speech, and the cranial nerves were entirely normal, there was no facial weakness, and the tongue was normal. There was pyramidal weakness MRC grade 3 affecting the right arm and leg with right sided hyperreflexia and a right extensor plantar response. Joint position, vibration, and light touch sensations were normal, but pain and temperature sensation were diminished down the right side. Blood pressure was 150/90 and cardiorespiratory examination was otherwise normal. Fasting cholesterol was 5.5 mmol/l, but other routine blood tests …

Cognitive dysfunction adversely influences long term outcome after cerebral insult, but the potential for brain stem lesions to produce cognitive as well as physical impairments is not widely recognised. This report describes a series of seven consecutive patients referred to a neurological rehabilitation unit with lesions limited to brain stem structures, all of whom were shown to exhibit deficits in at least one domain of cognition. The practical importance of recognising cognitive dysfunction in this group of patients, and the theoretical significance of the disruption of specific cognitive domains by lesions to distributed neural circuits, are discussed.

We performed a blinded multireader study comparing MR angiography (MRA) with digital subtraction angiography (DSA) in 34 prospectively recruited patients who presented with acute subarachnoid haemorrhage (SAH). Two observers independently reviewed the MRA and DSA studies some months after clinical presentation. Presence of an aneurysm was rated on a 4-point confidence scale. Cases in which the initial interpretation of the observers varied were jointly reviewed to reach a consensus opinion. DSA was deliberately chosen not to represent the reference standard and the clinical course and surgical findings were used to explain significant differences between the consensus readings of MRA and DSA. Diagnostic confidence and interobserver agreement were, overall, higher on DSA than on MRA studies (ϰ DSA = 0.64 versus ϰ MRA = 0.52 with 95 % CI for Δ = ϰ DSA-ϰ MRA [–0.06, 0.31]). With both methods, discrepancies between observers were due to aneurysms overlooked rather than false-positive readings by one observer. Diagnostic accuracy therefore improved when the readings of the two observers were combined, particularly for MRA. Intermethod agreement was only fair and similar for both readers (ϰ reader 1 = 0.37 versus ϰ reader 2 = 0.32 with 95 % CI for Δ = ϰ reader 1-ϰ reader 2 [–0.02, 0.11]). Both interobserver and intermethod agreements improved when the data were analysed on a per-study (positive or negative study) rather than on a per-aneurysm basis. Differences in the consensus reading were due to five aneurysms (four single and one multiple) detected only with MRA and five (two single and three multiple) detected only with DSA. MRA and DSA should be regarded as complementary in the investigation of patients with acute SAH. DSA can no longer be regarded as the reference standard.

SUMMARY: We assessed the influence of inclusion (method 1) and exclusion (method 2) of intratumoral vessels when determining maximum relative cerebral blood volume (rCBVmax) in 3 types of low-grade gliomas (LGGs): astrocytomas, oligoastrocytomas, and oligodendrogliomas. Method 1 yielded significantly higher mean rCBVmax than method 2. However, only method 2 demonstrated a significant (P = .026) association between rCBVmax and membership of a differently ranked histologic category. Exclusion of intratumoral vessels appears, therefore, preferable when determining rCBVmax in LGGs.

Objective : The differentiation of supra-, juxta- and high infrarenal abdominal aortic aneurysms (AAA), which is essential for good surgical management, remains problematic. This prospective study assessed the value of highly overlapping vs. contiguous axial spiral computed tomography (CT) reconstructions in the pre-operative assessment of AAA. Patients and methods : Thirty-five patients with abdominal aortic aneurysms were studied with spiral CT (10 mm collimation, pitch 1). Axial reconstructions were performed at 2 and 10 mm increments and compared with surgical findings. Using each protocol, the aneurysms were classified as infra-, juxta- or suprarenal. Observers also assessed visualization of main and accessory renal artery origins and identification of other surgically relevant vascular anomalies. Results : The 2 mm protocol correctly identified 29/31 infrarenal, 3/3 juxtarenal and 1/1 suprarenal aneurysms; two infrarenal aneurysms were overestimated as suprarenal. The 10 mm protocol correctly classified 25/31 infrarenal, 3/3 juxtarenal and 1/1 suprarenal aneurysms; five infrarenal aneurysms were overestimated as juxtarenal ( n = 3) or suprarenal ( n = 2) and one case was equivocal. Correct classification was thus 94% using the 2 mm protocol and 83% with the 10 mm protocol ( P = 0.063). All 70 main renal artery origins were visualized with the 2 mm protocol, while the 10 mm protocol missed six ( P = 0.03) The 2 mm protocol identified 10 accessory renal arteries, four of which were missed by the 10 mm protocol. Both protocols demonstrated five surgically relevant venous anomalies. Conclusion : Spiral CT with highly overlapping axial reconstructions correctly classified 94% of abdominal aortic aneurysms; overlapping reconstructions were particularly useful in differentiating high infrarenal from juxtarenal aneurysms

Background Subclinical acute ischaemic lesions have recently been described in spontaneous intracerebral haemorrhage (sICH). We hypothesised that they are related to MRI markers of small vessel disease [SVD] (hypertensive arteriopathy or cerebral amyloid angiopathy [CAA]) in a multicentre, cross-sectional study. Methods We studied consecutive patients with sICH from four stroke centres, and age-matched stroke referrals without sICH. Acute ischaemic lesions were assessed on MRI ( Results We included 114 sICH patients (39 with probable CAA); and 47 controls. The prevalence of DWI lesions was 9/39 (23%) in probable CAA-related ICH vs 6/75 (8%) in the remaining patients with sICH (p=0.024); no DWI lesions were found in controls. DWI lesions were associated with WMC score (OR 1.14 per unit increase, p=0.024) and strictly lobar CMBs (OR 3.85, p=0.029). Conclusion Acute, subclinical ischaemic brain lesions are frequent after sICH, and three times more common in CAA-related ICH than in other ICH types. They are associated with WMC and CMBs, suggesting that they result from an occlusive small vessel arteriopathy. They contribute to the overall burden of vascular-related damage in ICH, and may be a useful surrogate marker of ongoing ischaemic injury from SVD.