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Biomedical subjects

S Sheth

Publications and source records attributed to S Sheth.

At least 55 records · Page 3Linked to original sources
PubMed1995

Single- and double- lumen silicone breast implant integrity: prospective evaluation of MR and US criteria.

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) and ultrasound (US) criteria for breast implant integrity. MATERIALS AND METHODS: One hundred twenty-two single-lumen silicone breast implants and 22 bilumen implants were evaluated with surface coil MR imaging and US and surgically removed. MR criteria for implant failure were a collapsed implant shell ("linguine sign"), foci of silicone outside the shell ("noose sign"), and extracapsular gel, US criteria were collapsed shell, low-level echoes within the gel, and "snowstorm" echoes of extracapsular silicone. RESULTS: Among single-lumen implants, MR imaging depicted 39 of 40 ruptures, 14 of 28 with minimal leakage; 49 of 54 intact implants were correctly interpreted. US depicted 26 of 40 ruptured implants, four of 28 with minimal leakage, and 30 of 54 intact implants. Among bilumen implants, MR imaging depicted four of five implants with rupture of both lumina and nine of 10 as intact; US depicted one rupture and helped identify two of 10 as intact. Mammography accurately depicted the status of 29 of 30 bilumen implants with MR imaging correlation. CONCLUSION: MR imaging depicts implant integrity more accurately than US; neither method reliably depicts minimal leakage with shell collapse. Mammography is useful in screening bilumen implant integrity.

Breast Implants↗
PubMed1995

Deferoxamine-induced platyspondyly in hypertransfused thalassemic patients.

Deferoxamine chelation therapy (widely used to reduce iron overload in hypertransfused thalassemic patients) has been implicated in causing skeletal growth abnormalities (rachitic-like changes in the long bones and vertebral body flattening), particularly when used in early infancy and at high dose levels. Radiographs of seven hypertransfused and well-chelated patients with thalassemia were reviewed. For two patients, serial films of the spine from the early 1970s to the present revealed a sequence of changes in the vertebral bodies, beginning with normal bodies that became bulbous and subsequently flattened. These two patients had begun deferoxamine chelation therapy early in infancy. The bone changes, though slightly reminiscent of post-radiation changes, are milder and result in a final Scheuermann-like picture.

Adult↗
PubMed1994

Breast implant rupture: diagnosis with US.

PURPOSE: To characterize sonographic criteria for the detection of implant rupture. MATERIALS AND METHODS: One hundred nineteen symptomatic women (221 silicone implants) were evaluated with ultrasound (US) over 11 months to detect implant rupture. Fifty-nine breast prostheses in 31 women were surgically removed. RESULTS: Five sonographic findings associated with rupture were identified: echogenic noise, low-level homogeneous echoes within the implant, echogenic lines coursing within the implant, a contour bulge of the implant, and peri-implant fluid accumulations. The most useful finding in the detection of implant rupture was low-level homogeneous echoes, which were associated with 55% of ruptured implants and 16% of intact implants. This was statistically significant, achieving a 55% sensitivity and 84% specificity for the detection of implant rupture. Nine of 22 ruptured implants (41%) displayed none of the described criteria. CONCLUSION: US may be useful to detect implant rupture; however, a larger prospective study is necessary for adequate evaluation.

Equipment Failure↗
PubMed1994

Three-dimensional US: preliminary clinical experience.

PURPOSE: To evaluate applications of three-dimensional (3D) ultrasound (US) in a clinical setting. MATERIALS AND METHODS: Sixty-two patients were examined with experimental 3D US transducers coupled to a commercially available US unit and a computer workstation. Images were acquired in either the sagittal or transverse plane and were reconstructed in two orthogonal planes, transverse and sagittal; the C-plane, parallel to the transducer surface; and a volumetric rotational transparency display. RESULTS: A variety of normal and diseased abdominal and superficial organs and selected fetal anatomy, and pathologic conditions were imaged. 3D US allowed display of anatomy and pathologic conditions in planes usually not possible with conventional two-dimensional (2D) US. CONCLUSION: Preliminary data suggest that 3D US may become a valuable clinical tool and adjunct to 2D US. 3D US allows depiction of normal and abnormal structures in previously unattainable planes, thus facilitating diagnosis and increasing operator diagnostic confidence.

Abdomen↗
PubMed1993

Endovaginal sonography of the nongravid uterus.

Endovaginal sonography allows excellent visualization of the endometrium, including the cyclic changes seen in premenopausal women and the normal postmenopausal endometrium. The spectrum of abnormalities affecting the endometrium and myometrium, including foreign bodies, infection, fluid collections, hyperplasia, and neoplasia, is also best assessed with endovaginal sonography. It has also become the imaging modality of choice for examining women with postmenopausal bleeding. In these patients, analysis of the sonographic appearance of the endometrium, combined with duplex and color Doppler evaluation of the endometrial vasculature, may allow differentiation of benign from malignant processes.

Adult↗
PubMed1993

Diagnosing breast implant rupture with MR imaging, US, and mammography.

A total of 135 symptomatic women with 262 breast implants were examined with magnetic resonance (MR) imaging performed with a body coil, ultrasound (US), or both to determine imaging features of implant rupture. Surgical proof was available for 33 women with 62 implants; 24 were ruptured and 38 were intact. Complicated internal structure was the most reliable predictor of implant rupture: Diffuse low-level echoes were seen on sonograms in 56% of ruptured implants; internal membranes (which correspond to the collapsed implant shell) were seen on MR images in 58% of ruptured implants. Fluid droplets were seen within the silicone in 26% of ruptured implants on MR images. Irregular implant contour can be a sign of rupture but is unreliable. Fluid collections around silicone implants are not a sign of rupture. At present, neither US nor conventional MR imaging with a body coil is sufficiently reliable to advocate routine screening of asymptomatic women with breast implants. Evaluation with MR imaging performed with a surface coil is more reliable.

Breast↗
PubMed1993

Thickened endometrium in the postmenopausal woman: sonographic-pathologic correlation.

A correlative sonographic and histopathologic analysis was performed in 35 postmenopausal women with greater than 5-mm thickening of the endometrium at pelvic sonography. Women undergoing estrogen replacement were excluded from study. Four distinct sonographic patterns were encountered. Pattern 1 consisted of echogenic endometrium with small cysts (endometrial polyp with cystic hyperplasia [n = 9], atrophic endometrium with cystically dilated glands [n = 5], and atrophic endometrium [n = 3] at microscopic examination). Pattern 2 was homogeneous echogenic endometrium (proliferative endometrium [n = 3] and adenomyomatous polyp [n = 1]). Pattern 3 was irregular, inhomogeneous endometrium with ill-defined hypoechoic areas (endometrial carcinoma [n = 5], complex hyperplasia with atypia [n = 1], blood clots [n = 1], and atrophic endometrium with eosinophilic metaplasia [n = 1]). Pattern 4 was thin endometrium with fluid in the endometrial cavity (scant atrophic endometrium [n = 6]). Thus, an endometrial thickness of greater than 5 mm in postmenopausal women is associated with a variety of pathologic conditions. Subclassification of sonographic patterns may be helpful in differentiating benign cystic atrophy or cystic endometrial hyperplasia from malignant endometrial lesions.

Aged↗
PubMed1993

Transvaginal color Doppler sonography of adnexal masses: differences in blood flow impedance in benign and malignant lesions.

OBJECTIVE: The purpose of this study was to assess the blood flow characteristics of adnexal masses before surgical excision and to determine whether color flow Doppler sonography is useful for distinguishing benign from malignant masses. SUBJECTS AND METHODS: Thirty-one adnexal masses were evaluated with color flow Doppler transvaginal sonography. The pulsatility index and resistive index were calculated from the waveforms generated from blood flow within the ovary. Twenty-five lesions were benign and six were malignant on pathologic examination. Benign lesions included six endometriomas, six mesothelial cysts, three serous and one mucinous cystadenoma, three mature cystic teratomas, two hemorrhagic corpus luteum cysts, one cystadenofibroma, one sclerosing stromal cell tumor, one paratubal cyst, and one ovary that had undergone torsion with infarction. The malignant lesions consisted of three papillary serous cystadenocarcinomas, one granulosatheca cell tumor, one immature teratoma, and one metastasis of colon cancer to the ovaries. RESULTS: Benign tumors and cysts had a significantly higher pulsatility index (mean, 1.93 +/- 1.02; range, 0.23-3.99) and resistive index (mean, 0.77 +/- 0.22; range, 0.2-1.0) than did malignant tumors (pulsatility index: mean, 0.77 +/- 0.33; range, 0.31-1.09; resistive index: mean, 0.5 +/- 0.17; range, 0.27-0.67). However, some overlap in individual values for benign and malignant lesions was found. CONCLUSION: Our preliminary data suggest that high pulsatility and resistive indexes indicate benign adnexal processes; however, considerable overlap in pulsatility and resistive indexes between benign and malignant lesions was noted, and further work is needed before the validity of these factors is proved.

Adnexal Diseases↗
PubMed1992

Routine prophylactic oophorectomy at the time of vaginal hysterectomy in postmenopausal women.

Our experience with the routine removal of ovaries at the time of vaginal hysterectomy for 150 postmenopausal women is presented. The records of these women were compared with 200 women who underwent simple vaginal hysterectomy. The additional step of vaginal oophorectomy did not add to the morbidity of vaginal hysterectomy, and it is recommended that routine oophorectomy be considered for postmenopausal women having a vaginal hysterectomy.

Female↗
PubMed1991

Bladder exstrophy-epispadias complex: prostatic evaluation by transrectal ultrasonography.

Seven patients with bladder-exstrophy-epispadias complex underwent high resolution prostatic ultrasonography in order to establish the presence and appearance of their prostate gland and seminal vesicles. Six patients had been born with classic bladder exstrophy, and one patient with complete epispadias. The size of the prostate gland was in the normal range in three patients. Three patients had small glands, and in one patient no prostatic tissue could be identified. Two patients showed an unusual position or echoappearance of their glands. The seminal vesicles in five patients were relatively large, contained multiple cystic spaces, and/or extended posteriorly and inferiorly to the prostate gland proper. Our study demonstrates that the prostate gland and seminal vesicles are present in patients with bladder exstrophy. The unusual appearance, position, and size in most patients, however, suggests faulty embryologic development or changes secondary to surgery reflecting the complex nature of the condition. Likewise, the enlarged seminal vesicles may indicate impaired drainage of these structures secondary to the initial bladder closure or subsequent bladder neck reconstruction.

Adolescent↗
PubMed1991

Changes in renal artery Doppler indexes following renal angioplasty.

Doppler indexes were measured in 14 renal arteries in 13 patients before and after percutaneous transluminal angioplasty to determine if changes in these parameters occurred after the procedure. Angioplasty was technically and clinically successful in 12 cases, and adequate Doppler signals were obtained from 13 of 14 arteries. The pulsatility index, resistive index, and acceleration of the distal main renal artery Doppler waveform increased significantly after angioplasty, while the time to systolic peak and the renal-aortic ratio remained unchanged. The former may be useful noninvasive indexes to screen patients for restenosis of the renal artery before it becomes clinically evident. A long-term follow-up study is needed to test this hypothesis.

Adult↗
PubMed1991

Capsular transgression of prostatic carcinoma: evaluation with transrectal US with pathologic correlation.

One hundred twenty-five patients with biopsy proved clinical stage A or B prostatic carcinoma were evaluated with biplane transrectal ultrasonography (US) prior to radical prostatectomy. Sonograms were evaluated for capsular transgression of the tumor into the posterior and posterolateral aspects of the glands as manifested by local contour deformity and irregularity or interruption of the periprostatic fat echoes. Correlation of the findings at US with the findings at pathologic examination of the step sections was obtained, and the presence and depth of capsular penetration were assessed. Of the 250 halves or hemispheres of the prostate gland that were evaluated, capsular penetration was seen at pathologic examination in 86. US enabled correct identification of pericapsular tumor spread in 59 of the 86 hemispheres but did not depict pericapsular tumor spread in 27 hemispheres. Absence of pericapsular tumor spread was verified at pathologic examination in 149 of the 164 hemispheres that either did not have tumor or did not show pericapsular tumor spread. Pericapsular tumor spread was incorrectly diagnosed in 15 hemispheres. A positive US diagnosis of pericapsular tumor spread correlated moderately well with the depth of penetration demonstrated at pathologic examination. Transrectal US is an effective noninvasive procedure that demonstrates the presence of prostatic cancer.

Biopsy↗
PubMed1991

Stage A adenocarcinoma of the prostate: transrectal US and sonographic-pathologic correlation.

Results of transrectal ultrasound (TRUS) of the prostate and pathologic examination of specimens obtained at transurethral resection of the prostate (TURP) were compared in 29 patients with clinical stage A adenocarcinoma. Ten specimens contained no residual tumors larger than 5 mm in diameter; in the remaining 19 glands, 20 discrete cancers were found. At TRUS, 30 peripheral hypoechoic lesions were demonstrated, of which 11 corresponded to carcinoma at pathologic examination. Other hypoechoic peripheral zone lesions included a focal area of dilated acinar glands in 10 cases, post-TURP scarring with fingerlike projections of fibrosis in seven, dysplasia in one, and no correlation in one. Of nine tumors that were not detected prospectively at TRUS, eight were predominantly in the anterior zone and one was in the posterior peripheral zone but was isoechoic. Overall, the sensitivity of TRUS in the evaluation of clinical stage A lesions was 55% and the specificity was 37%. Clinical stage A carcinomas may be difficult to detect at US, and findings are often nonspecific. Any suspicious peripheral zone lesion should undergo biopsy with TRUS guidance before being diagnosed as malignant.

Adenocarcinoma↗
PubMed1991

Stage B adenocarcinoma of the prostate: transrectal US and pathologic correlation of nonmalignant hypoechoic peripheral zone lesions.

Various benign conditions have been found to cause hypoechoic lesions in the prostate gland, thus mimicking the sonographic appearance of early prostatic cancer. Transrectal sonograms in a large series of patients with biopsy-proved clinical stage B prostatic cancer were retrospectively reviewed to determine the pathologic correlate to benign hypoechoic peripheral zone lesions. Transrectal sonograms demonstrated hypoechoic lesions that did not represent cancer in 25 of 160 patients examined. All lesions were contralateral to the carcinoma. Pathologic correlation was found in 24 of the 25 lesions. The results of this study show that contralateral hypoechoic lesions in patients with pathologically proved prostatic cancer do not necessarily imply bilateral tumor involvement; they accounted for benign lesions that mimicked the sonographic appearance of malignant tumors and thus produced a false-positive rate for cancer in the contralateral lobe of 16% of patients (25 of 160) with clinical stage B cancer.

Adenocarcinoma↗
PubMed1991

Use of sonography to evaluate carotid atherosclerosis in the elderly. The Cardiovascular Health Study. CHS Collaborative Research Group.

Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies.

Age Factors↗