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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.

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

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.