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Biomedical subjects

B E Demas

Publications and source records attributed to B E Demas.

At least 19 recordsLinked to original sources
PubMed1992

Imaging of peritoneal pathology.

Advances in the imaging of peritoneal pathology are reviewed. Papers published in the past year in the radiologic, surgical, and pediatric literature discussed the detection, quantification, characterization, and management of fluid collections in the trauma patient or the patient with intra-abdominal sepsis; the assessment of various imaging modalities in the evaluation of unexplained fever or pain; and the detection, characterization, and localization of primary, recurrent, or metastatic abdominal neoplasms.

Diagnostic Imaging↗
PubMed1991

Varicoceles. Radiologic diagnosis and treatment.

The association of clinically apparent varicoceles with male subfertility and infertility has been noted in the urology literature since the late nineteenth century, and surgical ligation of varicoceles has been considered appropriate therapy in an attempt to improve semen quality and increase fertility for the past 40 years. It has been established by several authors cited herein that varicocele size does not predict prognosis after ligation reliably. Because subclinical varicoceles may affect testicular function and histologic characteristics adversely and because age at time of therapy may affect probability of successful enhancement of fertility, the interest of radiologists and urologists has been directed toward diagnosis and treatment of both clinically obvious and clinically occult varicoceles, particularly in young adult men or adolescent boys. Testicular growth after varicocele ligation in adolescent boys also suggests a benefit from early intervention. Sonographic evidence of a varicocele must be correlated with analysis of semen for sperm density, motility, and morphology, as not all patients with varicoceles are infertile. Although surgical therapy is standard for varicocele occlusion, fairly extensive evidence exists to show that percutaneous transvenous occlusion of varicoceles is feasible, safe, and effective, particularly in the setting of varicocele recurrence after conventional surgical treatment.

Embolization, Therapeutic↗
PubMed1990

MR imaging of bladder neoplasms: correlation with pathologic staging.

This retrospective study describes the accuracy of magnetic resonance (MR) imaging in determination of local disease extent in 34 examinations performed for evaluation of primary or recurrent bladder carcinoma. The 34 examinations were carried out in 29 patients (17 men, 12 women, aged 34-89 years). All studies were followed within 30 days by surgical and pathologic evaluation. Images were interpreted by two radiologists unaware of clinical or pathologic findings. MR imaging staging conformed to the TNM system of the International Union Against Cancer (IUAC). Pathologic evaluation showed bladder neoplasms in all cases; three patients' pathologic specimens contained two or more histologic types of tumors. MR imaging staging of the depth of tumor invasion was correct in 85% of examinations. Sensitivity of MR imaging for detection of deep muscle invasion was 97%, specificity 83%, and accuracy 94%. Sensitivity of MR imaging for detection of extravesical tumor extension was 95%, specificity 100%, and accuracy 97%. Sensitivity for detection of pelvic lymph node metastases was 50%, specificity 100%, and accuracy 82%. Our population included many patients with locally advanced disease. This pattern reflects standards of clinical practice by which superficial lesions are staged and resected endoscopically, and deeply invasive tumors are imaged prior to radical surgery.

Adult↗
PubMed1989

Superior sulcus tumors: CT and MR imaging.

Thirty-one patients with superior pulmonary sulcus tumors underwent a total of 32 sets of computed tomographic (CT) and magnetic resonance (MR) imaging examinations before receiving therapy. Prospective, independent, and blinded interpretations of the studies were compared with both the surgical findings (15 patients) and the patient's clinical symptoms (17 patients). Thin-section (5-mm) coronal and sagittal MR images proved more accurate than CT scans (.94 accuracy with MR imaging, .63 with CT) in evaluation of tumor invasion through the superior sulcus. The improved accuracy of MR imaging in this region appears almost certainly to be related to the improved display of the anatomy of the superior sulcus on thin-section coronal and sagittal images.

Adenocarcinoma↗
PubMed1988

Advances in imaging.

The introduction of sonography, x-ray computed tomography, magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS) have enhanced the radiologist's ability to delineate and stage neoplasms in all parts of the human body. Images of excellent quality can be generated within a reasonable time frame and with minimal biologic risk. All of the more sophisticated imaging modalities are costly and none can, isolated from clinical data, provide histologic diagnoses. Within the next few years it is anticipated that the speed of magnetic resonance image acquisition will increase and that contrast agents for MRI will be brought into clinical use. Evaluation of cost-effectiveness will continue and new diagnostic algorithms can be expected to evolve.

Diagnostic Imaging↗
PubMed1988

Ogilvie's syndrome. Successful management without colonoscopy.

We reviewed the clinical presentation, management, and outcome of 25 patients with Ogilvie's syndrome (acute colonic pseudoobstruction) at Memorial Sloan-Kettering Cancer Center from 1982 through 1985. All patients had cancer and severe associated medical problems. Abdominal x-rays uniformly showed cecal distension ranging between 9 and 18 cm. Twenty-four of the 25 patients were treated with conservative nonendoscopic management. One patient had an exploratory laparotomy for prophylactic cecostomy after only one day of conservative therapy. Of the 24 patients treated conservatively, 23 (96%) improved by both clinical and radiologic criteria in a mean of 3.0 days. The remaining patient died of multisystem failure not related to the acute colonic pseudoobstruction. Colonoscopic decompression was not attempted in any of the 25 patients. There were no colonic perforations, and there were no pseudoobstruction-related deaths. This study questions the need for early endoscopic or surgical treatment in cancer patients with acute colonic pseudoobstruction.

Colonic Pseudo-Obstruction↗
PubMed1988

Pelvic lipomatosis: diagnosis and characterization by magnetic resonance imaging.

While the number of reported cases of pelvic lipomatosis has been relatively small, this entity's prevalence is probably underestimated. Disease progression can cause hydroureteronephrosis and renal failure, and clinical follow-up is mandated after diagnosis. Diagnosis is based on detection of characteristic findings in conventional radiographs and computed tomographic (CT) images. We report here the magnetic resonance imaging (MRI) features of pelvic lipomatosis in 5 male patients, 2 of whom ultimately required placement of a ureteral stent to alleviate mechanical obstruction. Multiplanar MRI not only allows diagnostic confirmation comparable to that possible with CT but also provides delineation of cephalad displacement of the bladder base, elongation of the bladder neck and posterior urethra, and elevation of the prostate gland. The MR images show characteristic medial and superior displacement of the seminal vesicles and show fatty tissue separating the prostate gland from the rectum. The noninvasive nature and low biological risk of MRI are desirable features, particularly when serial evaluation of pelvic anatomic distortion is necessary.

Adult↗
PubMed1988

Detection and staging of renal neoplasms: a reassessment of MR imaging.

The use of magnetic resonance (MR) imaging in the detection and staging of renal neoplasms was investigated in 104 patients with 106 renal cell carcinomas confirmed at surgery or autopsy. Overall, MR imaging demonstrated 101 of 106 lesions (95%), including all 93 tumors that were larger than 3 cm in diameter but only eight of the 13 smaller tumors (62%). MR imaging enabled accurate staging of 82% of all detected lesions but led to the understaging of nine lesions and the overstaging of nine. At present, MR imaging cannot be used as a screening modality for renal tumors. However, its negative predictive values of 98% and 99%, respectively, for the evaluation of tumor vascular extension and tumor spread to adjacent structures makes it an excellent staging modality that should be used when the CT findings are equivocal. MR imaging is not accurate in indicating bowel and mesentery involvement, but rapid technical advances and the introduction of bowel contrast medium may improve this present limitation.

Adult↗
PubMed1988

Soft-tissue sarcomas of the extremities: comparison of MR and CT in determining the extent of disease.

A prospective comparison of the accuracy of MR and CT in determining the anatomic extent of disease was carried out in 40 patients who had histologically proved soft-tissue sarcomas of the extremities. Tumor resection, performed by using either en bloc excision or amputation in all patients, allowed detailed pathologic verification of imaging findings. Image analysis included measurement of maximum tumor dimensions, notation of tumor position in relation to deep fascia, recording of anatomic compartment and individual muscle involvement, and documentation of the spatial relationships between tumor, neurovascular structures, underlying bones, and joints. MR and CT were equally accurate in measurement of maximal tumor diameter, detection of tumor depth, and delineation of tumor, neurovascular, osseous, and articular relationships. Evaluation of anatomic compartment and individual muscle involvement was more accurately accomplished with MR imaging; nine (23%) of 40 MR studies showed tumor involvement of one or more individual muscles that appeared normal in CT scans. These results suggest that MR imaging may be the staging procedure of choice in patients with soft-tissue sarcomas of the extremities.

Adolescent↗
PubMed1987

Magnetic resonance imaging evaluation of radiation-induced changes in experimentally implanted renal cell carcinoma.

The effect of radiation on the magnetic resonance imaging appearance and relaxation parameters of human renal cell tumors implanted in male white-Swiss athymic nude mice was evaluated. Twenty-three mice were treated with external beam radiation, receiving a total dose of 2,500 rads administered in a single treatment limited to subcutaneous tumor. Twenty-two tumor-bearing mice served as control animals. Experimental and control mice were studied with MRI at four (n = 9), seven (n = 20), 14 (n = 8), and 28 (n = 8) days following experimental radiotherapy. A 0.35 tesla superconductive MRI system was employed. Images were generated using spin-echo technique with repetition times (TR) of 500 and 2,000 ms and echo-delay times (TE) of 28 to 30 and 56 to 60. Relaxation time calculations were made on the basis of tumor signal-intensity measurements in assigned regions of interest. The MRI appearances and relaxation times of irradiated tumors that decreased in size following treatment, irradiated tumors that grew, and control tumors were similar, as were their histologic features. No statistically significant differences could be detected in relaxation times of the four experimental and four control groups. Statistical evaluation was performed using analysis of variance. Further investigation of MRIs potential in tissue characterization following radiotherapy is warranted, but evaluation of change in tumor dimensions remains the most reliable indicator of therapeutic response.

Animals↗
PubMed1986

Utility of ceruletide in promoting intestinal opacification for abdominal and pelvic computed tomography.

An analysis of the utility of parenteral ceruletide, a cholecystokinin-like synthetic decapeptide, in promoting bowel opacification for computed tomography (CT) scanning was performed. Abdominal and pelvic CT scans of 85 patients who had received intramuscular ceruletide following oral contrast administration and of 85 control patients were reviewed and the degree of bowel opacification evaluated. No significant advantage was conferred by ceruletide in opacifying the stomach or major part of the small intestine. However, a statistically significant difference was found between the 2 groups in the presence or absence of contrast in the terminal ileum and right colon. Contrast was detected in the terminal ileum in 52 experimental compared with 35 control patients (p less than 0.009) and in the right colon in 56 experimental and 39 control subjects (p less than 0.01). Intramuscular administration of ceruletide will be helpful when terminal ileal opacification is essential or in patients in whom colonic opacification is desired but rectal contrast contraindicated.

Ceruletide↗
PubMed1986

Magnetic resonance imaging in the evaluation of the retroperitoneum.

Magnetic resonance imaging techniques have made it possible to delineate a variety of pathologic processes in the retroperitoneum, including lymphadenopathy, atherosclerotic and aneurysmal disease of the aorta, congenital venous anomalies, and primary and secondary retroperitoneal neoplasms. The availability of multiplanar image display, the excellent soft tissue contrast resolution, and the fact that exogenous contrast materials are not needed are valuable assets of this imaging modality.

Arteries↗
PubMed1986

Uterine MR imaging: effects of hormonal stimulation.

Magnetic resonance (MR) imaging characteristics of the uterine corpus were evaluated in 40 women divided into five physiologic categories (nine premenarchal, 13 reproductive age not taking hormones, seven reproductive age taking oral contraceptives, six reproductive age taking gonadotropin releasing hormone analog, and five postmenopausal). Images were generated using a 0.35-T magnet and a double spin-echo technique. On both T1-weighted and T2-weighted images, premenarchal and postmenopausal uteri were small and relatively featureless. Uteri on T2-weighted images in reproductive age women not taking exogenous hormones showed variations in endometrial and myometrial width, signal intensity, and T1 and T2 values during the menstrual cycle. Oral contraceptives and gonadotropin releasing hormone analogs caused endometrial atrophy and alterations in myometrial signal intensity and T1 and T2 values. A detailed gynecologic history is therefore essential in the evaluation of uterine anatomy in patients undergoing pelvic MR imaging.

Atrophy↗
PubMed1986

Renal allografts: evaluation by MR imaging.

The value of magnetic resonance (MR) imaging in assessing renal transplants was prospectively studied in 45 patients with 46 allografts. Four allografts were imaged at two different times, and separate diagnoses were given for both examinations. Therefore, this study was based on 50 proved diagnoses: nine normally functioning allografts, four allografts with acute tubular necrosis (ATN), 29 with acute rejection, one with chronic rejection, five with cyclosporin nephrotoxicity, and two with local inflammation secondary to adjacent abscess. Twenty-seven of the allografts had concomitant fluid collections. Normal renal structures with preservation of corticomedullary contrast (CMC) on T1-weighted images were demonstrated in all the normally functioning allografts. Decreased or absent CMC on T1-weighted images, reflecting a long T1 relaxation time for cortex, was found to be the most consistent sign of acute renal allograft rejection (27/29). No abnormalities on on MR images were observed in allografts compromised by cyclosporin nephrotoxicity. Hydronephrosis of the renal allograft was easily diagnosed with MR. Perirenal abscess (three cases) and perirenal hematomas (five cases), because of their higher MR signal intensity on T1-weighted images (TR = 0.5 sec, TE = 28 msec), could be differentiated from clinically insignificant postoperative fluid seromas (seven cases), lymphoceles (11 cases), and urinoma (one case).

Adult↗
PubMed1986

Gestational trophoblastic neoplasm of the uterus: MR assessment.

Magnetic resonance (MR) imaging characteristics of uterine gestational trophoblastic neoplasia were prospectively studied in nine women (aged 21-58 years). MR imaging was done at the time of initial clinical diagnosis, after each of the first two cycles of chemotherapy, and 6-9 months after initiation of chemotherapy. Sagittal and transverse MR images of the pelvis were generated with a 0.35-T superconducting magnet and the double spin-echo technique with short and long repetition times (TRs). The neoplasm distorted the MR appearance of uterine zonal structures (myometrium, endometrium, and junctional zone) and demonstrated hypervascular masses of heterogeneous signal intensity. Favorable response to chemotherapy was determined by a decrease in serum beta-subunit human chorionic gonadotropin (HCG) concentrations, and was accompanied by MR findings of regression of vascular abnormalities, development of intralesional hemorrhage, and return of normal appearance of uterine zones. The return of uterine zonal anatomy on MR images antedated definitive decrease in uterine volume. All eight patients imaged 6-9 months after initial imaging showed normal uterine volume and zonal anatomy.

Adult↗