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Background and purpose: To establish radiological features in the atypical MV2 subtype of sCJD compared with the classical MM1 subtype, as well as region- and sequence-dependent inter-observer correlation. Methods: MRI hyperintensity of basal ganglia (BG), cortex and thalamus was evaluated in 31 MM1 and 32 MV2 patients. Each MR scan was analyzed independently by two neuroradiologists blinded to PRNP genotype/prion protein type. Results: Cumulative T2-sensitivity for BG hyperintensity was higher in the MV2 subtype (84% for both observers versus 61% in observer 1/42% in observer 2 in MM1 patients). Significant inter-observer agreement was found for BG and thalamus on T2, FLAIR, PD and DWI, but for cortex only on DWI. Thalamic changes were significantly more frequent in MV2 than in MM1 patients (cumulative sensitivity 86% vs. 12.5% on DWI). Discussion: The high frequency of thalamic hyperintensity in the MV2 subtype allowed differentiation from MM1 patients. Good inter-observer agreement was found for BG and thalamus in all sequences. DWI showed the highest inter-observer correlation independent of the investigated brain region and was therefore not only highly sensitive but also relatively independent of investigator bias. Since inter-observer correlation for cortical hyperintensity in T2, FLAIR and PD is relatively low, the cortical changes should not be over-interpreted with these sequences.

Introduction Creutzfeldt-Jakob Disease (CJD) is a rare fatal neurological disease, with four distinct forms. Sporadic CJD (sCJD) is the most common and is characterized by a rapidly progressive dementing illness, associated with EEG abnormalities and CSF protein changes (14-3-3 protein). In addition, there are characteristic magnetic resonance imaging (MRI) changes, consisting of basal ganglia (putamen and caudate head) hyperintensity. Although these abnormal appearances overlap with other diseases, their presence is diagnostically useful. In variant CJD (vCJD), the form of CJD associated with bovine spongiform encephalopathy (BSE), the pulvinar sign – a characteristic appearance of bilateral hyperintensity in the posterior nuclei of the thalamus – is highly specific for the diagnosis of variant CJD in the appropriate clinical context. This article reviews these and other MRI appearances of CJD. Background The transmissible spongiform encephalopathies (TSE) are a group of diseases affecting man and other animals, characterized by a fatal progressive neurological illness, characteristic

Creutzfeldt-Jakob Disease (CJD) is a rare, progressive and invariably fatal neurodegenerative disease characterized by specific histopathological features. Of the four subtypes of CJD described, the commonest is sporadic CJD (sCJD). More recently, a new clinically distinct form of the disease affecting younger patients, known as variant CJD (vCJD), has been identified, and this has been causally linked to the bovine spongiform encephalopathy (BSE) agent in cattle. Characteristic appearances on magnetic resonance imaging (MRI) have been identified in several forms of CJD; sCJD may be associated with high signal changes in the putamen and caudate head and vCJD is usually associated with hyperintensity of the pulvinar (posterior nuclei) of the thalamus. These appearances and other imaging features are described in this article. Using appropriate clinical and radiological criteria and tailored imaging protocols, MRI plays an important part in the in vivodiagnosis of this disease.

An active program of corneal transplantation depends upon a constant supply of high quality donor tissue. We describe an effective and inexpensive system of corneal donor retrieval in a major teaching hospital, and present an analysis of its donor population. During the five-month period studied in detail (May to October 1991), 365 deaths occurred in the hospital. The relatives of the decreased were contacted and consent for donation was requested after 323 (88.5%) of these deaths. Consent was given in 212 cases (65.5% of requests), with a mean age of the donor population of 69 years. After screening donor tissue for quality, 110 pairs of corneal buttons and 10 globes of sclera were dispatched for surgery during the study period, giving an overall procurement rate of over 30%. Further, the efficient notification and 'on-call' retrieval system led to very rapid corneal retrieval, resulting in an average death to storage medium time of less than two hours.

A previously well 62-year-old man presented with a 6-month history of dizziness, unsteadiness and intermittent diplopia. Neurological examination revealed slightly reduced visual acuity of 6/9 in both eyes, a mild right-over-left skew deviation, sensorineural hearing loss, brisk re exes with bilateral extensor plantars, and right-sided cerebellar signs with an ataxic gait. On general examination, a 12 12 cm diameter dusky compressible cutaneous mass was noted over the nape of the neck. On enquiry this was determined to have been a vascular naevus present since birth. Routine blood tests were unremarkable. Laboratory testing of the cerebrospinal uid revealed a raised protein level of 1.22 g/l as well as numerous red blood cells and associated xanthochromia. CT of the brain and orbits was normal. Magnetic resonance imaging (MRI) (1.5 Tesla) of the brain showed extensive marked linear hypointensity over the pial surface of the brainstem, the folia of the cerebellum, and the cortical surface of the Sylvian and interhemispheric ®ssures bilaterally, in keeping with extensive super®cial haemosiderosis (Fig. 1). Cerebral MRI angiography and subsequent four-vessel cerebral angiography were normal. An MRI of the whole spine showed extensive haemosiderin deposition over the entire cord and conus, but no intra-axial lesion or lesion within the subarachnoid space. However, the cutaneous naevus was contiguous with a large soft tissue mass which extended into the left paravertebral soft tissues (Fig 2). An ultrasound examination of the cutaneous mass revealed a well-de®ned area of reduced echogenicity demonstrating ow on Doppler examination, in keeping with a vascular malformation. An arch aortogram and selective subclavian angiograms were normal. A venogram following direct percutaneous puncture of the lesion revealed a large venous vascular malformation, with dilated vessels extending into the cervical exit foraminae (Fig. 3). A diagnosis of super®cial haemosiderosis secondary to chronic haemorrhage from a thoracic subcutaneous venous vascular malformation was made. DISCUSSION

Atypical clinical course and low sensitivity of established diagnostic tests are the main diagnostic problems in the MV2 subtype of sporadic Creutzfeldt-Jakob disease (sCJD). Clinical symptoms and signs, MRI, EEG and biochemical CSF markers were studied in 26 patients. Histological findings were semiquantitatively evaluated. Compared with typical sCJD, the disease duration was prolonged (median 12 months). Dementia, ataxia and psychiatric symptoms were present in all patients. Extrapyramidal signs were observed in 88%. T2-weighted MRI showed basal ganglia hyperintensities in 90%. Increased thalamic signal intensity was detected in 88% on diffusion-weighted MRI. Increased CSF tau-protein was found in 83%, and the 14-3-3 test was positive in 76%. The EEG revealed periodic sharp wave complexes in only two patients. Kuru plaques, severe thalamic and basal ganglia gliosis and spongiform changes, and neuronal loss in the pulvinar were the prominent histological features. At least one of the three diagnostic tests (MRI, tau- and 14-3-3 protein) supported the clinical diagnosis in all patients. MRI was the most sensitive of the diagnostic tests applied. Thalamic hyperintensities were observed unusually frequently. Prolonged disease duration, early and prominent psychiatric symptoms, absence of typical EEG, thalamic hyperintensities on MRI and relatively low 14-3-3 protein sensitivity may be suspicious for variant CJD. However, distinct sensory symptoms and young age at onset, which are often found in the latter, are not common in the MV2 subtype, and the pulvinar sign was observed in only one case.

BACKGROUND AND PURPOSE: Variant Creutzfeldt-Jakob disease (vCJD) is a rare but important cause of dementia and death in young patients and is causally linked to bovine spongiform encephalopathy. Symmetrical hyperintensity in the pulvinar (posterior) nuclei of the thalamus (pulvinar sign) on brain MR images was described as a specific, noninvasive, diagnostic sign of vCJD in a previous small series. This purpose of this larger study was to evaluate this sign prospectively and further define the MR imaging characteristics of vCJD. METHODS: As part of the ongoing surveillance program in the United Kingdom, MR images of suspected cases of vCJD were collected during a 6-year period. All available images were assessed prospectively by one observer for the presence of the pulvinar sign. Images of neuropathologically confirmed cases were then assessed independently by two neuroradiologists for the degree of hyperintensity of the pulvinar on images of different MR sequences, and for the presence of abnormal hyperintensity in other areas of the brain. Discrepancies were reviewed jointly and a consensus opinion formed. RESULTS: Prospective analysis identified the pulvinar sign in 74 of 82 cases of vCJD. In the retrospective study, the pulvinar sign, as defined by hyperintensity of the pulvinar relative to the anterior putamen, was present on seven (9%) of 75 T1-weighted, 77 (71%) of 108 T2-weighted, 47 (81%) of 58 proton density-weighted, and 30 (100%) of 30 fluid-attenuated inversion-recovery (FLAIR) images. Diffusion-weighted images were available in two cases and were positive for the pulvinar sign in one. Other features were hyperintensity of the dorsomedial thalamic nuclei (93%), caudate head (40%), and periaqueductal gray matter (83%) on FLAIR images. CONCLUSION: In the appropriate clinical context, demonstration of the pulvinar sign on MR images is a highly accurate diagnostic sign for vCJD. FLAIR sequence is more sensitive than other sequences. Positive MR images may obviate more invasive diagnostic tests in most cases.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging can disclose distinct hyperintense lesions in Creutzfeldt-Jakob disease (CJD). However, these findings and chronologic changes of CJD at diffusion-weighted imaging have not been fully investigated. Our purpose was to assess the diagnostic value of diffusion-weighted imaging in depicting CJD-related lesions and in tracking the evolution of these lesions. We also compared the sensitivity of diffusion-weighted imaging in depicting CJD-related lesions to that of fluid-attenuated inversion recovery (FLAIR) imaging. METHODS: We reviewed findings in 13 patients with a diagnosis of CJD who underwent MR imaging, including diffusion-weighted imaging. Nine patients were initially examined within 4 months of onset of symptoms (early stage), and eight were examined 4 months or later (late stage). We evaluated four items: 1) distribution of lesions at diffusion-weighted imaging, 2) conspicuity of lesions at diffusion-weighted imaging and FLAIR imaging, 3) chronologic changes in lesions at diffusion-weighted imaging, and 4) chronologic changes in lesions revealed by apparent diffusion coefficient (ADC) maps. RESULTS: Patients had striatal lesions or cerebral cortical lesions or both. The thalamus was involved in only one patient, and the globus pallidus was spared in all patients. The sensitivity of diffusion-weighted imaging in depicting lesions was superior or at least equal to that of FLAIR imaging. Hyperintense lesions at diffusion-weighted imaging changed in extent and intensity over time. Unlike infarction, lesional ADC decreased for 2 weeks or longer. CONCLUSION: The progressively hyperintense changes in the striata and cerebral cortices at diffusion-weighted imaging are considered characteristic of CJD. Diffusion-weighted imaging may be useful for the early diagnosis of CJD.

This study assessed the first year of a regional general practitioner (GP) open-access neuroimaging service, to determine diagnostic yield and influence on patient management. Overall, 48.1% of examinations demonstrated a radiologically significant abnormality with 64.1% of spinal imaging examinations demonstrating significant findings. Utilised appropriately, a regional open-access neuroimaging service has good diagnostic yield and may influence the management of most referred patients.

The deep grey matter structures of the brain have been reported to show MR hyperintensity in the sporadic form of Creutzfeldt-Jakob disease (sCJD), but the criteria for visual judgment of this are not well defined. We carried out a quantitative study of T2 weighted and proton density scans comparing 10 sCJD patients with 10 non-CJD dementia controls (NCD) and also with 11 patients suffering from the new variant form of CJD (vCJD). Scans were acquired in a clinical context and came from many hospitals. Absolute intensities varied widely and did not allow any useful discrimination. In all groups the putamen had a gradient of reducing intensity from anterior to posterior on T2 scans. In both s- and v- CJD patients this gradient was increased. Sensitivity and specificity (SS (2) intensities of deep grey matter structures vary systematically and intensity-based segmentation methods used in patients and normals should take account of this.

OBJECTIVES The accuracy of magnetic resonance angiography (MRA) was determined in patients with recently symptomatic tight (80%–99%) carotid stenosis (on Doppler ultrasound), and the effect of stenosis severity on the accuracy and interobserver variability of MRA was studied. METHODS Forty four consecutive patients undergoing intra-arterial angiography (IAA) before carotid endarterectomy were prospectively studied, in two centres with identical MR scanners and sequences. All patients had undergone Doppler ultrasound, showing a 70% or worse carotid stenosis on the symptomatic side. MRA and IAA were done during the same admission. The MRA films were each independently and blindly read for percentage stenosis (signal gap if present) by four observers. The IA angiograms were read separately by one observer, blind to symptoms, and Doppler and MRA results. RESULTS Signal gaps on MRA were seen in stenoses ranging from 67% to 99% on intra-arterial angiography. Magnetic resonance angiograms consistently overestimated the percentage stenosis according to intra-arterial angiography. Clinically significant misclassification of stenosis occurred according to MRA in 7% of patients, and was more frequent as carotid stenosis increased. CONCLUSION Significant diagnostic errors occur with MRA in patients with tight carotid stenosis. Any morbidity occurring as a result of misclassification by MRA is likely to be offset by the avoidance of complications; however, this could only be determined with certainty in a randomised controlled trial.

The completeness and accuracy of registration of primary intracranial tumours in the Scottish Cancer Registry was compared with a detailed incidence study performed over a two year period (1989-90). Of 228 patients with any primary intracranial tumour in the incidence study, 124 (54%) were identified as intracranial tumours in the cancer registry. The registry excluded benign tumours (although this was not consistent) and so the sensitivity of the registry varied with tumour type (84% for neuroepithelial tumours, 22% meningeal, 29% sellar, 0% cranial nerve). Of the 31 malignant tumours not found in the registry on our initial search, nine were found to have been included between 1989‐90 but using diVerent International Classification of Diseases-9th revision (ICD-9) codes or postcodes, and seven were found registered after 1990. Eleven per cent of cases (18/170) identified in the cancer registry were excluded from the incidence study: 11 had evidence of an intracranial tumour before 1989 whereas four definitely did not have an intracranial tumour. The cancer registry therefore significantly underestimated the incidence of all primary intracranial tumours, and of malignant intracranial tumours.Incidence studies must use additional methods to identify all primary tumours. Cancer registries should consider registering all primary intracranial tumours and may improve case ascertainment by screening neuroradiology data. (J Neurol Neurosurg Psychiatry 1997;63:94‐97)

99m Technetium-MDP bone scintigrams in 11 patients with ankylosing spondylitis were reviewed. Increased activity in sacroiliac joints was present in five of 11 cases, all of whom had symptoms of less than 5 years duration. Patients with longstanding disease had normal or low sacroiliac joint activity. In the spine, appearances included diffuse symmetrical, unifocal or multifocal asymmetrical increased uptake involving the costovertebral, costotransverse and facet joints as well as the spinous processes. In advanced disease with extensive ankylosis, the lumbar spine was featureless on scintigraphy, except for focal increased activity at the site of previous fracture in one patient. Of six available views of the sternum, increased uptake was present in five at the manubriosternal joint and five at the sternoclavicular joints. Increased peripheral uptake was mainly in the hips and knees in advanced cases. Plain radiographic changes correlated poorly with scintigraphic changes, scintigraphy detecting considerably more lesions than radiography. Awareness of the scintigraphic appearances of ankylosing spondylitis may lead to diagnosis before the development of radiographic changes and avoid confusion with other pathology. Clinical indications for bone scintigraphy in ankylosing spondylitis are suggested.

The first dedicated, public hospital day-case eye surgery unit opened in Melbourne in June 1987. This report details the mode of operation of this unit, and analyses the 218 procedures performed in the first 15 months of operation, and includes an assessment of the level of patient acceptance.

Thirty-five patients have had 39 consecutive epikeratoplasty procedures (12 adult aphakic, 9 pediatric aphakic, 12 myopic, and 6 keratoconic eyes) by the same surgeon, using commercially prepared lenticules. The lenticule remained totally clear in 85% of eyes. Two lenticules were removed due to infection and scarring; four lenticules had minimal scarring and did not require removal. Spectacle-corrected acuity was worse than one line from the preoperative spectacle-corrected acuity in 58% of the adult aphakic eyes; however, 75% were 20/50 or better postoperatively. Fifty percent were within 2 diopters (D) of emmetropia and 92% within 3 D. All pediatric aphakic patients showed an improvement in best-corrected acuity, and 83% of eyes at 6 months were within 2 D of emmetropia; by 1 year a 3.4-D average myopic shift had occurred. Two of the six eyes (33%) using the original myopia technique were within 2 D of emmetropia, whereas five of the six eyes (83%) with the current technique are within this range. Spectacle-corrected acuity in the entire current myopia group has either improved by one or more lines or has remained unchanged. Five of the six keratoconic eyes had 20/40 or better spectacle-corrected and 20/25 contact lens-corrected acuity postoperatively; average corneal flattening was 6 D. Persistent epithelial defect and irregular astigmatism were the principal factors in delay in visual recovery.

Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea.

Elective penetrating keratoplasty has been performed on an outpatient basis on 37 patients since July 1987. The commonest indications have been herpetic keratitis, keratoconus, and pseudophakic or aphakic corneal oedema. Local anaesthesia, with little or no sedation, was used in most cases, and only three patients had a general anaesthetic. Accompanying procedures have included anterior vitrectomy, extracapsular cataract extraction with posterior chamber lens implantation and IOL exchange. The results demonstrate that outpatient keratoplasty is a safe, effective alternative to hospitalisation, and has a very high level of patient acceptance.

Epikeratoplasty has been performed on eight eyes of seven patients by one surgeon in Melbourne since March 1988. All cases were contact lens or spectacle intolerant. Standard surgical techniques utilising donor lenticules imported from the United States and including an annular keratectomy were employed for the procedure. An eight-month follow-up is available for the first two cases, aged two and 10 years. The elder of these children has achieved corrected acuity of 6/9 in each eye. Refractive and early visual acuity results are presented for the five other cases which have at least two months of follow-up. The results indicate that in appropriately selected patients, epikeratoplasty offers a safe, effective modality for visual restoration and development in otherwise untreatable aphakic children.