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Biomedical subjects

M T Freedman

Publications and source records attributed to M T Freedman.

8 recordsLinked to original sources

Evaluation of the painful shoulder. A prospective comparison of magnetic resonance imaging, computerized tomographic arthrography, ultrasonography, and operative findings.

Twenty-one patients who had had pain in the shoulder for more than three months were evaluated with ultrasonography and magnetic resonance imaging followed by computerized tomographic arthrography. The results of the imaging studies were then compared with the operative findings. Magnetic resonance imaging was found to be the most useful modality for establishment of the etiology of pain in the shoulder due to disease of the rotator cuff, instability associated with abnormality of the glenoid labrum, subacromial impingement, stenosis of the coracoacromial arch, and osteoarthrosis of either the glenohumeral or the acromioclavicular joint. The accuracy of magnetic resonance imaging was found to depend on both the operator and the technique and was decreased in extremely obese patients, due to difficulties in positioning, and in patients who had had a previous operation. Magnetic resonance imaging was more accurate than either computerized tomographic arthrography or ultrasonography in identifying partial-thickness tears (intrasubstance changes in the rotator cuff). Magnetic resonance imaging provided the same level of accuracy as computerized tomographic arthrography in the detection of abnormalities of the glenoid labrum.

Adolescent

Magnetic resonance imaging of peripheral soft tissue hemangiomas.

Ten patients with soft tissue hemangiomas outside the central nervous system were studied with MR imaging. Eight patients were studied at 1.5 Tesla (T) with T1-weighted and triple echo T2-weighted sequences. Two additional patients were imaged on a 0.5-T system. The MR images were correlated with images from other modalities. Histologic diagnosis was obtained in all cases. It was found that prolonged T2-weighted imaging together with standard spin echo T1 and T2 pulse sequences is a good substitute for contrast-enhanced CT and arteriographic evaluation of soft tissue hemangiomas.

Adolescent

Post-traumatic osteochondroma.

Osteochondromas can arise as primary, spontaneous tumors of bone or in previously irradiated bone. We report a patient who developed an osteochondroma of bone which arose secondary to previous trauma. This has not previously been reported.

Adolescent

Policies and attitudes toward the pregnant radiology resident.

To evaluate attitudes and policies toward pregnant radiology residents, a questionnaire was sent to the chiefs of radiology residency programs across the country. A return rate of 76.4% and a response rate of 75.4% were achieved. A large majority of the respondents indicated that schedule changes would be made to avoid excessive exposure of a pregnant resident to radiation. The accommodations they suggest are reviewed, and suggestions are made that would help alleviate some of the stress and conflicts that invariably arise when a resident becomes pregnant.

Attitude

Crossed renal ectopia.

Crossed renal ectopia is an unusual congenital anomaly, probably produced by abnormal development of the ureteral bud. The deformity itself produces no symptoms and the clinical presentation generally is for obstruction and infection. In our series the adult patients presented most commonly with urinary tract infections, while the pediatric patients presented most often with multiple congenital anomalies, especially of the skeletal system.

Abnormalities, Multiple

Beneficial effect of propranolol in a histologically appropriate model of postischemic acute renal failure.

Acute renal failure caused in the rabbit by clamping one renal pedicle for 1 hour and removing the opposite kidney produced a histologic picture very similar to that observed in "hypotensive" acute renal failure in man. Intravenous infusion of propranolol, a drug which prevents renin release, at 1 mg/kg for 70 minutes beginning at time of pedicle clamping resulted in significantly lower serum creatinine in this model (2.8 +/- 0.2 mg% at 48 hours with propranolol versus 5.2 +/- 0.8 mg% without). Renin stimulation by dehydration or feeding a low-salt diet enhanced the difference between treated and untreated groups (2.6 +/- 0.4 mg% with propranolol versus 6.2 +/- 1.8 mg% without, after dehydration; 3.5 +/- 1.0 mg% with propranolol versus 7.6 +/- 1.4 mg% without, after low-salt diet).Suppression of renin production by saline feeding eliminated propranolol's beneficial effect (5.6 +/- 0.9 mg% with propranolol versus 4.0 +/- 0.6 mg% without). In rabbits with a normal food and water intake, renal denervation using phenol also eliminated propranolol's effect (creatinine 8.6 +/- 1.4 mg% with propranolol versus 8.6 +/- 1.8 mg% without). In rabbits with intact kidneys, flow probe recording of renal blood flow showed a significantly higher blood flow immediately after unclamping in the propranolol-treated animals, and renal angiograms showed less vasoconstriction in this group after unclamping. In this model of acute renal failure, renal vasoconstriction plays an important role following the initial ischemic insult. Propranolol lessens the severity of this vasoconstriction and the resulting acute renal failure. Its probable action is interference with neurogenically stimulated renin release.

Acute Kidney Injury