Diffusion-weighted MRI in paediatric neuroimaging.

Diffusion-weighted imaging (DWI) is a well-established technique in neuroimaging, but the diagnostic value of DWI outside the setting of acute infarct and abscess is sometimes under-recognised particularly in paediatric neuroimaging. DWI also plays an important role in the evaluation of intracranial infection, brain tumours, demyelinating diseases, and metabolic disorders. DWI can assist in the early detection and characterisation of intraocular and skull-base pathology. The cases presented in this article demonstrate the utility of DWI in paediatric neuroimaging. DWI can improve diagnostic sensitivity and in conjunction with other magnetic resonance imaging (MRI) sequences can aid in early diagnosis and management. Obtaining an early diagnosis may avoid potential complications and improve patient outcome.

Normal neuroanatomical variants that may be misinterpreted as disease entities.

Variations of normal development and benign incidental anomalies are frequently observed on diagnostic neuroimaging. It is important these are recognised for what they are, as misinterpretation may result in unnecessary further investigation, follow-up imaging and anxiety. In this article, we review benign intracranial anomalies commonly referred to our unit for specialist neuroradiology advice or multidisciplinary discussion, concerning cysts of the pineal gland and pituitary fossa, vascular anomalies, and perivascular spaces. This article outlines the embryology and development, the various imaging features as well as the clinical relevance and differential diagnoses of each normal neuroanatomical variant.

A giant cause of stroke.

An 80 year old man presented subacutely with drowsiness and confusion. Subsequent MRI brain imaging demonstrated multiple posterior circulation infarcts. Extracranial vasculitis was suspected when his ESR was found to be high and vascular imaging showed multifocal irregular narrowing of both vertebral arteries. This was confirmed by targeted temporal artery biopsy, which showed chronic granulomatous inflammation typical of giant cell arteritis (GCA). The patient made a significant recovery following treatment with prednisolone.

Isolated intracranial Rosai-Dorfman disease in a child, a case report and review of the literature.

BACKGROUND: Rosai-Dorfman disease (RDD), otherwise known as sinus histiocytosis with massive lymphadenopathy (SHML), usually affects young adults and commonly presents with massive painless cervical lymphadenopathy. Extranodal disease is present in a third of patients, and it is recognised that this can involve the central nervous system. Intracranial RDD is rare in adults and fewer than 10 paediatric cases have been reported. CASE: A 10-year-old boy with isolated intracranial RDD presents with a painless forehead mass. The management is discussed and the literature reviewed. CONCLUSION: This case of isolated intracranial RDD highlights the importance of considering RDD in the differential of paediatric intracranial mass lesions and outlines the diagnostic and treatment challenges faced when managing this rare condition.

Acute subarachnoid haemorrhage: is a negative CT angiogram enough?

AIM: To determine the negative predictive value of 16 channel multisection computed tomography angiography (CTA) for detecting aneurysms in spontaneous subarachnoid haemorrhage (SAH), using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: The prospectively collected cerebral angiogram database of Department of Neuroradiology, Atkinson Morley Regional Neuroscience Centre was used to identify 200 consecutive patients who had undergone DSA for SAH. Of these, 176 had undergone CTA prior to DSA. Clinical details and radiology reports were correlated and images of positive investigations reviewed. RESULTS: DSA showed one or more cerebral aneurysms in 105 (60%) patients. These were correctly reported on CTA in 100. CTA was reported negative for aneurysms in 74 patients. Of these five were false negative and had aneurysms detected on DSA. In the CTA/DSA negative group, 11 (16%) patients had classical perimesencephalic clinical syndrome and blood distribution. There were two false positives at CTA. For ruptured cerebral aneurysms, CTA had 95.2% sensitivity, 97.2% specificity, 98.1% positive predictive value, and 93.2% negative predictive value. CONCLUSION: The sensitivity and negative predictive value of CTA for ruptured aneurysms remains imperfect. Continued use of DSA is recommended in most patients with a negative CTA after acute SAH. Confirmation of a negative CTA result with DSA may not be routinely required in patients with perimesencephalic syndrome.

Carotid intima-media thickness is greater but carotid plaque prevalence is lower in black compared with white subjects.

BACKGROUND AND PURPOSE: Carotid IMT is widely used as a surrogate marker for atherosclerosis. Prospective studies in largely white populations demonstrate that it is strongly associated with carotid plaque and is an independent predictor of stroke. There are few data from black populations. In a previous study, we showed that carotid IMT is increased in black individuals in the UK. The purpose of this study was to confirm this with a larger sample size and to establish whether raised IMT in black stroke-free individuals is associated with increased carotid plaque. MATERIALS AND METHODS: High-resolution sonography was used to measure the CCA-, BIF-, and ICA-IMT and plaque in 306 black and 281 white healthy individuals recruited by random community sampling from London, U.K. Mean CCA-IMT was determined by using a semiautomated computer program that detects the blood/intima borderline and the media/adventitia borderline with the use of a gray-value algorithm. RESULTS: CCA-IMT was higher in black compared with white individuals after controlling for cardiovascular risk factors and socioeconomic status (ß = 0.050; 95%CI, 0.024-0.076; P < .001). BIF- and ICA-IMT were also increased in black subjects. In contrast, carotid plaque was more common in white individuals (OR, 2.90; 95%CI, 1.41-5.96; P = .004). CONCLUSIONS: The lack of correlation between increased IMT and carotid plaque in black individuals implies that IMT should not currently be used as a surrogate marker of atherosclerosis in black populations. It suggests that the increased IMT seen in black individuals may not represent early atherosclerosis.

Picture archiving and communication systems lead to sustained improvements in reporting times and productivity: results of a 5-year audit.

AIM: To evaluate the impact of picture archiving and communications systems (PACS) on reporting times and productivity in a large teaching hospital. MATERIALS AND METHODS: Reporting time, defined as the time taken from patient registration to report availability, and productivity, defined as the number of reports issued per whole time equivalent (WTE) radiologist per month, were studied for 2 years pre- and 3 years post-PACS installation. Mean reporting time was calculated for plain radiographs and specialist radiology techniques [computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine]. Productivity, total department workload, and unreported film rates were also assessed. Pre- and post-PACS findings were compared. RESULTS: Between 2002-2006 the number of radiological patient episodes increased by 30% from 11,531/month to 15,057/month. This was accompanied by a smaller increase in WTE reporting radiologists, from 32 to 37 (15%). Mean reporting times have improved substantially post-PACS, plain radiograph reporting time decreased by 26% (from 6.8 to 5 days; p=0.002) and specialty modalities by 24% (4.1 to 3.1 days; p<0.001). Radiologist productivity has increased by 18% (337 films to 407 films/WTE radiologist/month). Unreported films have decreased from 5 to 4% for plain radiographs and are steady for specialty modalities (< 1%). In most areas improvements have been sustained over a 3-year period. CONCLUSION: Since the introduction of PACS, reporting times have decreased by 25% and the productivity improved by 18%. Sustained improvements are felt to reflect the efficiencies and cultural change that accompanied the introduction of PACS and digital dictation.

Histological and ultrastructural studies of the marsupial Didelphis albiventris Peyer's patches

Differing from the studied Eutheria the white belly opossum Peyer"s patches do not present a conspicous dome. M cells are located in the inmer layer of bilaminal invaginations formed at the bottom of the villi. A great variation in the morphology of M cells was observed. The enterocytes located at the epithelial inner layer may present endocytic vesicles, and the microvilli are shorter tha the microvilli of enterocytes lining the small intestine. As these morphological aspects have been described to exist in the enterocytes of the lancet opossum small intstine it was surmised that the opossum Peyer's patches special epithelium could represent the persistence in adult animals of a cellular pattern established before the intestinal maturation had occurred