Twenty cases of surgically verified pituitary microadenoma (17 with Cushing disease and three with acromegaly) were studied with positron emission tomography (PET) with use of fluorine-18-2-fluorodeoxyglucose (FDG). The diagnostic results were compared with those of other modalities, namely, computed tomography (CT), magnetic resonance (MR) imaging, and, in the cases of Cushing disease, simultaneous bilateral inferior petrosal sinus sampling (SIPS). The PET results showed 12 positive readings and one questionable reading, compared with seven positive readings and one questionable reading for CT (18 cases studied) and 13 positive and two questionable MR imaging readings. PET complemented MR imaging, in the sense that five of the positive PET readings were negative or questionable at MR imaging. PET studies of 20 healthy control subjects showed no false-positive cases, whereas other studies of healthy subjects with contrast material-enhanced CT and MR imaging have yielded, respectively, 20% and 15% positive readings, with findings suggestive of silent or occult adenomas.

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Magnesium is the second most abundant intracellular cation. Deficiency can cause several neurological complications, including cerebellar syndromes, with various MRI findings. These include cerebellar oedema, presumably through a similar mechanism to that in posterior reversible encephalopathy syndrome (PRES). People particularly vulnerable to deficiency include those with high alcohol consumption, excessive loss due to gastrointestinal pathology and those taking certain medications, including proton pump inhibitors. We report three patients with cerebellar syndromes associated with hypomagnesaemia. These cases support the previously reported association between hypomagnesaemia and reversible cerebellar dysfunction and illustrate the range of potential presentations. They highlight an uncommon but treatable cause of cerebellar ataxia that may present to acute neurological liaison services.

A description is given of a simple, inexpensive and versatile method for estimating underwater weight. The use of a portable stock tank allows the determination of % Fat by underwater weighing without requiring a swimming pool, built-in tank, or special facility. Twenty-eight college students were weighed on two separate testing sessions 24-48 hours apart. Ten trials were performed at each session. The mean of the last five trials was used in determining underwater weight. The test-retest reliability coefficient was high, r = 0.98, and most of the successive trial correlations were above 0.99. The mean % Fat for the women (N = 9) was 22.2 ± 5.9 and for the men (N = 19) was 13.7 ± 5.1.

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