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Biomedical subjects

H L Stein

Publications and source records attributed to H L Stein.

At least 19 recordsLinked to original sources

Not so rapid progression of peripheral vascular disease after diagnostic angiography.

It was recently reported that peripheral vascular disease may progress so rapidly after diagnostic angiography that most likely the diagnostic procedure is in some way responsible. Because flow-limiting arterial stenoses often become complete occlusions within hours or days of the diagnostic procedure, it was recommended that angioplasty be performed immediately after diagnostic angiography to avoid this complication. The authors attempted to confirm these findings before implementing this recommendation. In fact, they did not confirm the findings. Among 96 flow-limiting stenoses considered for angioplasty, the procedure was performed in 31 on the same day. Among the remaining 65 cases, in 64 the stenosis did not occlude and angioplasty was successfully performed. Only one stenosis was discovered to have thrombosed, and this occurred 3 weeks after diagnostic angiography. These results indicate that there is not such rapid progression of peripheral vascular disease after diagnostic angiography. It is not necessary to perform angioplasty of stenotic lesions emergently, and treatment is not impaired by electively scheduling the patient for the next available day.

Angiography↗

Spondyloarthropathy from long-term hemodialysis.

Twenty-six patients undergoing long-term hemodialysis who had hand and wrist abnormalities were examined for the presence of concurrent spinal disease. Six patients (23%) were found to have spinal disease on radiographs. In four, the findings resembled those of a destructive spondyloarthropathy, and in two, a less destructive erosive arthritis. A review of the spinal radiographs of 31 patients with normal hands and wrists revealed no such abnormalities. Postmortem examinations of two patients with spondyloarthropathy demonstrated extensive deposition of beta-2 microglobulin, an amyloid-like substance. The authors conclude that the disease is similar in both areas and represents a skeletal response to chronic renal failure and long-term hemodialysis. The disease may occur more frequently with an increased duration of hemodialysis, in one area of the skeleton if another area is already affected, and is probably not infectious if multiple areas are involved.

Adult↗

Contrast venography: reassessment of its role.

To compare contrast venography with noninvasive methods, 353 patients clinically suspected of having deep venous thrombosis were examined with venography and independently with combined Doppler flow sounds and plethysmography. Noninvasive examinations had a sensitivity of 96% and a specificity of 90%. Positive noninvasive tests had a 94% predictive value, and negative noninvasive tests had a 93% predictive value. The overall accuracy of the noninvasive tests was 94% (331 of 353) compared with venography. Since venography itself may be subject to misinterpretation, noninvasive examinations should be the preferred initial method for diagnosing deep venous thrombosis. Venography should be reserved for situations that require additional diagnostic confirmation.

Blood Flow Velocity↗

Imaging strategies for MRI of the pelvis.

Appropriate patient triage of pelvic diseases depends upon a problem-solving approach as outlined in this article. Whether MRI is chosen as an adjunct to US or CT or as the primary modality, as in the staging of malignancy, imaging strategies for pelvic MRI can be tailored to the organ of interest and to the clinical question being asked.

Female↗

MRI in staging of endometrial and cervical carcinoma.

MRI of 54 patients with endometrial and cervical carcinoma was performed on a 0.6-T superconducting magnet. In 18 of 24 cases of surgically proved endometrial carcinoma, MRI accurately showed the depth of myometrial invasion. MRI was superior to CT scan for defining the primary site and extent of the tumor in 14 of 24 cases. Of 25 patients with cervical carcinoma studied, MRI was superior to CT scan in 15 of 19 cases with CT correlation for localizing the primary site. MRI showed parametrial extension and invasion of surrounding structures but is probably less reliable than CT scan for detection of adenopathy because of false positive findings from volume averaging with bowel.

Adenocarcinoma↗

The value of MRI in evaluating perirectal and pelvic disease.

MRI of the perirectal region is facilitated by the superb soft tissue contrast, multiplanar imaging capability, lack of respiratory motion artifact and absence of clip artifact which can hamper visualization by CT scan. MRI provides distinct advantages over CT scanning without the need for ionizing radiation or the injection of intravenous contrast material. This study reviews the findings in 18 consecutive patients with a variety of perirectal pathologies including rectal carcinoma (3), gynecologic neoplasm (8), sacral lesions (2), pelvic arteriovenous malformations (2), inflammatory bowel disease (2), and a pelvic kidney (1). In the perirectal region, MR was useful to show normal tissue planes, benign processes which can mimic neoplasm, intrapelvic extension of malignancy and adenopathy.

Adult↗

Osteoarthropathy of the hand and wrist in patients undergoing long-term hemodialysis.

Radiographs of the hand and wrist in 81 patients who had undergone hemodialysis for a minimum of 5 years (mean, 7.8 years) were reviewed. In 32 patients arthritic changes were found, consisting of articular erosions, joint space narrowings, periarticular cysts, and osteopenia. Seven of the 32 patients had periarticular calcific deposits. The frequency and severity of the radiographic findings increased with increasing duration of dialysis. It appears that in addition to the well-recognized secondary hyperparathyroidism there is another commonly occurring osteoarthropathy (40% in this series) related to long-term hemodialysis.

Adult↗

Cardiac magnetic resonance imaging in children with congenital heart disease.

Electrocardiogram-gated magnetic resonance imaging (MRI) was used to evaluate 36 children, ages 2 to 17 years, with congenital heart disease. With the use of multiple imaging planes, including transverse, sagittal, coronal, and 60-degree left anterior oblique views, high contrast images with excellent spatial resolution were produced. In 34 of the 36 patients the anatomic detail provided by MRI was sufficient to make the cardiac diagnosis. Electrocardiogram-gated MRI is an important new imaging technique for use in children with cardiovascular disease.

Adolescent↗

Nuclear magnetic resonance imaging in evaluation and follow-up of children treated for coarctation of the aorta.

Electrocardiographic-gated nuclear magnetic resonance imaging was used to evaluate 10 patients, aged 2.5 to 18 years, with coarctation of the aorta. Six patients had balloon dilation angioplasty, one had surgical repair and three are awaiting treatment. Imaging studies were performed before and after therapy in three patients. In all pretreatment studies, the sagittal and 60 degrees left anterior oblique imaging planes adequately revealed the anatomy of the coarctation. Post-treatment imaging studies demonstrated effective relief of the coarctation in all cases. In three of the six patients who had balloon angioplasty, there was a variable degree of dilation of the aorta at the site of the previous coarctation. Nuclear magnetic resonance imaging is an effective noninvasive imaging method for visualizing coarctation of the aorta and for follow-up after treatment.

Adolescent↗

Breast and axillary tissue MR imaging: correlation of signal intensities and relaxation times with pathologic findings.

We tested a variety of inversion-recovery (IR) and spin-echo (SE) sequences by imaging the breast masses of 22 patients before surgery and 23 tissue specimens with magnetic resonance (MR) imaging at 0.6 T to determine the most effective pulse sequences to evaluate breast disease. An SE pulse sequence using a long repetition time (TR) of 1,600 msec and a long echo time (TE) of 90 msec was found to be the most sensitive in depicting carcinoma in the excised tissue specimens, with all of the carcinomas (n = 15) demonstrating irregular areas of higher signal intensity (SI) than that of the adjacent fat. However, only five of 11 breast carcinomas present in the preoperative patients produced a higher SI than that produced by fat on the same T2-weighted sequence. Five of the remaining six carcinomas in the preoperative patients appeared as localized distortions of fibroductular architecture on both T2-weighted SE and IR sequences. In axillary tissue specimens, both metastatic carcinoma and hyperplastic lymph nodes produced a high SI on T2-weighted SE sequences. However, metastatic carcinoma had a significantly longer T2 relaxation time than did hyperplastic lymph nodes.

Adenofibroma↗

Nondilated obstructive uropathy: percutaneous nephrostomy performed to reverse renal failure.

Ureteral obstruction can lead to renal failure without involving detectable dilatation of the calyces, renal pelvis, or ureter proximal to the obstruction. This phenomenon was noted in seven patients who had clinical obstruction that we were not able to diagnose using computed tomography (CT) or ultrasonography (US). These patients underwent percutaneous nephrostomy (PCN), which resulted in brisk diuresis and improved renal function. We obtained an accompanying antegrade urogram in these cases, which demonstrated the level of obstruction and indicated that dilatation of the collecting system was minimal or not present. When obstructive uropathy is suspected, we believe it is essential to consider performing PCN to evaluate and potentially reverse renal failure, even when CT and US scanning do not demonstrate obstruction.

Acute Kidney Injury↗

Vascular magnetic resonance imaging.

Natural contrast from flow void potentiates the diagnosis of the intimal flap of aortic dissection, the dilated contour of aortic aneurysm, the protruding plaque of atherosclerotic disease, the recognition of deep vein thrombosis, and the identification of a number of acquired and congenital vascular abnormalities. Although MRI is costly at the present, the advantages of vascular MRI include noninvasive multiplanar imaging, no ionizing radiation, no contrast material requirements, and its use as an alternative to technically limited ultrasonography or computed tomography. MRI can define anatomy, measure blood flow, and be used for serial examinations in following disease processes and response to treatment. Future research with tissue characterization of atherosclerotic plaque may allow for early diagnosis and treatment of this ubiquitous disease. Not only chemical but also metabolic studies, including tissue perfusion in the heart and other solid viscera, would be of great value. Undoubtedly, MRI will have a permanent role in cardiovascular diagnosis.

Arteries↗

Tumor of the heart diagnosed by magnetic resonance imaging.

A case of liposarcoma metastatic to the heart is presented. This is a very rare entity and only three prior case reports could be found. Magnetic resonance imaging was successfully used to visualize the tumor. These images compared favorably with a two-dimensional echocardiographic study and postmortem examination.

Echocardiography↗

0.6 T magnetic resonance imaging of the orbit.

Magnetic resonance (MR) imaging of the orbit was performed with a 0.6 T superconducting imaging system in 100 patients with normal orbits who were being evaluated for brain pathology and in 21 additional patients with a variety of orbital lesions to determine the efficacy of MR imaging in displaying orbital abnormalities. Usually, MR studies were performed using a multislice technique with multiple spin-echo pulse sequences and 30, 60, and 90 msec echo times and 500, 1500, and 2000 msec repetition times. Using section thicknesses of about 8 mm, imaging was performed in the transaxial, coronal, and sagittal projections. Pixel size was 0.9 X 1.8 mm, and the examination took about 30 min. The MR findings were compared with computed tomographic (CT) findings in all cases. Either combined axial and coronal studies of 5-mm-thick sections or a thin axial study of 1-mm-thick sections followed by reformatting techniques to obtain multiplanar images was used. Contrast enhancement was used in the CT studies. Both MR and CT clearly demonstrated the soft-tissue abnormality in all cases except two, in which MR failed to detect the abnormality. In one, MR failed to detect a small retrobulbar hemorrhage that occurred after a surgical procedure for retinal detachment. In the second case, rather extensive calcification in the posterior choroidal layers and lens was not detected by MR imaging. In several other cases, MR provided information beyond that obtained with CT. MR has the advantage of providing exquisite anatomic detail in multiplanar images, and it appears to be more sensitive than CT in detecting small, subacute and chronic hemorrhage within soft-tissue masses in the orbit and in detecting ischemia of the globe. CT is superior to MR imaging in portraying fine bone detail.

Adult↗