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Biomedical subjects

D W Levy

Publications and source records attributed to D W Levy.

17 recordsLinked to original sources

Rotator cuff tears: prospective comparison of MR imaging with arthrography, sonography, and surgery.

Thirty-eight patients with suspected rotator cuff tears were examined at 1.5 T by using a loop-gap resonator surface coil. The MR findings were compared prospectively in a blinded fashion with the results from double-contrast arthrography in all 38 patients, high-resolution sonography in 23 patients, and surgery in 16 patients. In the total group of 38 patients, MR imaging detected 22 of 22 tears and 14 of 16 intact cuffs as determined by arthrography. In the 16 surgically proved cases, MR and arthrography showed identical results, with 92% sensitivity in the diagnosis of 12 tears and 100% specificity in the diagnosis of four intact cuffs. In a subgroup of 23 patients, sonography detected nine of 15 tears and seven of eight intact cuffs as determined by comparison with arthrography. In 10 surgically proved cases, sonography was 63% sensitive in the diagnosis of eight rotator cuff tears and 50% specific in the diagnosis of two intact cuffs. For the diagnosis of rotator cuff tears, MR imaging is comparable to arthrography in both sensitivity and specificity. In this study, sonography was not as accurate in the diagnosis of rotator cuff tears as were the other two techniques. These results suggest that MR imaging should be considered the noninvasive test of choice for patients with suspected rotator cuff disease.

Arthrography

Motion artifact reduction in MR imaging of the abdomen: gradient moment nulling versus respiratory-sorted phase encoding.

Two currently available methods of reducing motion-induced artifact on magnetic resonance (MR) images, respiratory-sorted phase encoding (RSPE) and gradient moment nulling (GMN), were compared in images of the upper abdomen obtained with long repetition and long echo times. For ten subjects, two series of axial MR images were obtained with identical parameters except that RSPE was used in one and GMN in the other. Images were evaluated by three independent radiologists, and region-of-interest measurements were obtained to calculate signal-difference-to-noise ratios (SD/Ns) for liver versus gallbladder and liver versus the right kidney. Maximum ghost intensity and the standard deviation of motion-induced noise were also calculated. GMN was superior to RSPE for motion artifact reduction in all ten cases. The SD/N for liver versus both gallbladder and right kidney was significantly higher with GMN. Presaturation pulses applied outside the volume of interest reduced aortic and inferior vena cava signal and virtually eliminated artifact from these vessels but did not noticeably affect signal from intrahepatic vessels. GMN combined with presaturation pulses is a highly effective method of motion artifact reduction in the upper abdomen.

Abdomen

Renal failure in the elderly.

A pilot study recording the incidence, management and outcome of renal failure in elderly patients presenting to three geriatric units in a six-month period is described. A total of 4001 patients were admitted during this time and 273 patients were considered to have renal failure at presentation (criteria, plasma urea level greater than or equal to 17 mmol/l and/or creatinine level greater than or equal to 160 mumol/l). In 151 patients (55 per cent) the cause was pre-renal and this form of renal failure had a good prognosis; over 60 per cent recovered and increasing age did not affect prognosis adversely. Ninety-six patients (35 per cent) had intrinsic renal disease which was commoner in younger patients and had a mortality rate of 48 per cent. In the majority of patients renal failure was mild, only 24 per cent having a urea level greater than 31 mmol/land/or creatinine level greater than 400 mumol/l.

Acute Kidney Injury

Thorotrast-induced hepatosplenic neoplasia: CT identification.

Despite discontinuation of its use in the 1950s, the consequences of Thorotrast usage continue to be recognized. In a review of plain film and CT findings of 20 cases of Thorotrast exposure, 15 of 17 patients demonstrated Thorotrast accumulation in the liver and spleen on plain films. Typically, this appeared as regions of trabeculated increased density within the liver. The spleen was of normal or decreased size and often demonstrated a finely punctate pattern of opacification. Only two malignancies could be suggested on plain film alone: one hepatic and one splenic. Five patients with hepatic malignancies underwent CT examinations: three with cholangiocarcinoma, one with angiosarcoma, and one with hepatocellular carcinoma. No specific criteria could be established to distinguish among these lesions, as each neoplasm appeared as relatively low-density mass(es). Two cases of splenic angiosarcoma appeared as low-density filling defect(s) in the otherwise opaque spleen, one case primary and the other metastatic from the liver. CT was superior to plain radiography in detecting and characterizing Thorotrast distribution and any superimposed malignancy. In addition to periodic liver function tests, screening CT of patients exposed to Thorotrast might detect hepatic neoplasms at an operable stage.

Adenoma, Bile Duct

Subungual keratoacanthoma.

The subungual keratoacanthoma is a benign neoplasm which simulates and must be differentiated from squamous cell carcinoma. Subungual keratoacanthomas are rapidly growing tumors, causing bone destruction which usually heal spontaneously. The lesion most often presents as a painful, enlarging mass in middle-aged Caucasian patients. Radiographic examination demonstrates a lytic cup-shaped erosion of the underlying distal phalanx. It is essential to recognize keratoacanthoma and separate it from squamous cell carcinoma, both for prognostic and therapeutic reasons. We present two cases of proven subungual keratoacanthoma and discuss their radiographic and histologic characteristics, as well as the current treatment alternatives for this entity.

Aged

Patterns of urine flow and electrolyte excretion in healthy elderly people.

Twenty four young (mean age 29.2 years, range 25-35) and 21 elderly (mean age 66.5, range 60-80) healthy subjects collected their urine in timed aliquots over 24 hours. The elderly subjects had been selected for their fitness by clinical and laboratory examinations and all lived independently at home. Sodium and potassium excretions were reduced in the elderly subjects compared with the young subjects, potassium excretion considerably so. This was despite similar 24 hour urine volumes and total solute excretion by both groups. The ratios of rates of excretion of water, electrolytes, and solutes during the night to the rates of excretion during the day were found to be higher in the elderly than the young subjects. Reduced day to night ratios of urinary excretion may be partly responsible for complaints of nocturia and sleep disturbance in elderly people.

Adult

Cimetidine in the treatment of herpesvirus infections.

In August 1977 a patient developed herpes zoster just before she commenced a course of cimetidine (Tagamet; Smith, Kline & French) for a chronic gastric ulcer. She experienced both rapid relief of the ulcer symptoms and, rather unexpectedly, dramatic relief of the herpetic pain and rapid disappearance of the eruption. On the basis of this observation cimetidine was prescribed to 21 patients with herpes zoster. The results continued to be encouraging in all but 3 patients. The trial was therefore extended to other herpesvirus infections. In all but 1 of 7 patients with herpes labialis the blisters were aborted, and in 1 patient with herpes keratitis the result was also encouraging, the attacks being markedly shortened in duration and reduced in frequency. The results of this preliminary trial warrant a systematic scientific inquiry into the potential role of cimetidine in the treatment of hypesvirus infection, as well as a study of the mechanisms involved.

Adolescent

Cryptococcosis associated with sarcoidosis: CT and MR findings.

Two cases of cryptococcal abscesses were identified in patients with sarcoidosis. The diagnostic imaging tests were not specific for cryptococcus prior to needle aspiration of the abscesses, but they did enable successful biopsy for diagnosis and treatment.

Adult