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Biomedical subjects

D Thickman

Publications and source records attributed to D Thickman.

At least 19 recordsLinked to original sources
PubMed1996

Effect of the number of core biopsies of the prostate on predicting Gleason score of prostate cancer.

PURPOSE: We determined the effect of the number of core biopsies of the prostate on predicting the Gleason score of the prostatectomy specimen. MATERIALS AND METHODS: The Gleason scores from 124 radical prostatectomy specimens were compared to those from preoperative core needle biopsies of the prostate. The number of cores obtained and tumor stage were compared regarding agreement in prostate cancer score. RESULTS: Four to 6 core biopsies yielded the best results, with agreement within 1 Gleason score in 75% of the cases. Further increases in the number of core biopsies did not improve results. Additionally, 37% of the well differentiated tumors on core biopsy were stage C. CONCLUSIONS: Gleason score from the core biopsy has limitations in respect to predicting prostatectomy tumor score and stage and, therefore, it is problematic for use in therapeutic decision making.

Analysis of Variance↗
PubMed1995

Solid breast nodules: use of sonography to distinguish between benign and malignant lesions.

PURPOSE: To determine whether sonography could help accurately distinguish benign solid breast nodules from indeterminate or malignant nodules and whether this distinction could be definite enough to obviate biopsy. MATERIALS AND METHODS: Seven hundred fifty sonographically solid breast nodules were prospectively classified as benign, indeterminate, or malignant. Benign nodules had no malignant characteristics and had either intense homogeneous hyperechogenicity or a thin echogenic pseudocapsule with an ellipsoid shape or fewer than four gentle lobulations. Sonographic classifications were compared with biopsy results. The sensitivity, specificity, and negative and positive predictive values of the classifications were calculated. RESULTS: Benign histologic features were found in 625 (83%) lesions; malignant histologic features, in 125 (17%). Of benign lesions, 424 had been prospectively classified as benign. Two lesions classified as benign were found to be malignant at biopsy. Thus, the classification scheme had a negative predictive value of 99.5%. Of 125 malignant lesions, 123 were correctly classified as indeterminate or malignant (98.4% sensitivity). CONCLUSION: Sonography can be used to accurately classify some solid lesions as benign, allowing imaging follow-up rather than biopsy.

Adolescent↗
PubMed1994

Magnetic resonance imaging of benign adnexal conditions.

Magnetic resonance imaging can be used to demonstrate a variety of benign adnexal diseases. However, the real utility and efficacy of MR imaging in benign pelvic disease has not been investigated thoroughly. This is the challenge for future research. Presently, particularly in light of changes in the health care system, it is incumbent upon radiologists, gynecologists, and other clinicians to determine what additional information MR imaging will add to the diagnostic evaluation already completed before performing MR imaging. One must ask several questions. Will MR imaging provide additional information? Will that information affect care and treatment of the patient? Will the treatment be beneficial to the care of the patient? Will the patient agree to the management? Many times these questions are not asked. And if asked, the answers are unknown or under investigation. However, using one's best clinical judgment and armed with the knowledge at hand, if answers to the above questions are yes, then MR imaging may prove useful.

Adnexa Uteri↗
PubMed1992

Comparison of orthoroentgenography and computed tomography in the measurement of limb-length discrepancy.

To determine the most accurate roentgenographic technique for the measurement of limb-length discrepancy, the twenty lower extremities of ten cadavera were measured with use of both orthoroentgenograms and lateral scout computed-tomographic scanograms. The actual anatomical limb length also was measured, to serve as a control. The effects of flexion of the knee joint, use of an external fixator, cost and time of the examination, and exposure to radiation also were determined. No statistically significant difference in the measurements of the length of the femur was found between the two methods at neutral or at 15, 30, or 45 degrees of flexion of the knee. However, computed tomography was significantly more accurate than orthoroentgenography in the measurements of length of the tibia and of total length of the limb when the knee was flexed to 30 degrees or more (p less than 0.01). The placement of an Ilizarov fixator did not alter the results. The cost and time necessary to complete an examination were comparable for the two methods. However, computed tomography delivered only 20 per cent of the radiation needed for orthoroentgenography. Computed tomography is more accurate than orthoroentgenography for the measurement of limb-length discrepancy in patients who have a flexion deformity of the knee.

Adult↗
PubMed1991

Popliteal artery entrapment: findings at MR imaging.

Magnetic resonance (MR) imaging can noninvasively demonstrate the anatomic relationships between the popliteal artery and the muscles within the popliteal fossa, making it an ideal screening test for popliteal artery entrapment prior to angiography or surgery. The authors describe a patient with bilateral type II popliteal artery entrapment in whom the anomaly was diagnosed in the asymptomatic extremity with MR imaging.

Adult↗
PubMed1991

Infection in utero: US findings in 19 cases.

The results of antenatal sonographic studies of 19 fetuses with congenital infections were retrospectively reviewed by the authors. Recognizing the significance of these antenatal sonographic findings is important because in utero infections can have devastating effects on the developing fetus. An infectious viral agent was isolated in laboratory tests at birth in 11 patients, and the effects of a viral agent were proved clinically in eight. Antenatal sonography demonstrated abnormalities in 18 fetuses: Multiple organ systems were affected in 47%; intracranial abnormalities, cardiac abnormalities, and parenchymal calcifications occurred in 42%, 37%, and 32%, respectively; large placentas were seen in 32%; and the volume of amniotic fluid was decreased in 37% and increased in 37%. Sixty-three percent of fetuses were either aborted or died at birth; the 37% that lived were all developmentally impaired. On the basis of these sonographic, laboratory, and clinical findings, the authors conclude that when multiple organ system abnormalities are found at antenatal ultrasound, the presence of an in utero infection should be considered. The parents should be informed that there is a poor prognosis for any fetus demonstrating such abnormalities.

Amniotic Fluid↗
PubMed1991

Bullet identification with radiography.

The authors provide a simple radiographic method for estimating bullet weight and caliber of both deformed and undeformed bullets that enables accurate determination of caliber for the gamut of bullet shapes, with known degrees of confidence. The weight-determination procedure is based on the correlation between bullet cross-sectional area, as derived from three orthogonal radiographs, and bullet weight, as determined from a data base of the properties of 48 bullets removed from humans. Different equations were developed for bullets weighing 5.8 g or less, or more than 5.8 g. For relatively undeformed bullets an additional method calculated caliber directly from the diameter of the bullet body on radiographs. Both methods enabled correct prediction of the weight and caliber of the bullets; if one method could not be used, results of the other were reliable. Testimony based on these results has been accepted in a local police case and may meet requirements for testimony in U.S. court cases involving gunshots.

Firearms↗
PubMed1991

Amniotic sheets: natural history and histology.

Eleven amniotic sheets were detected on obstetric ultrasound. Ten of these were reviewed retrospectively and one was followed prospectively throughout gestation. Amniotic sheets are single, planar reflective membranes. Evidence presented here suggests that these membranes are composed of four distinct layers: two layers of chorion sandwiched between two layers of amnion. Their mean thickness is 2.4 mm in the midportion and 4.5 mm at the free edge. A thick triangular base is frequently seen. Amniotic sheets change little during pregnancy; however, they are more difficult to identify late in gestation. They are unassociated with fetal anomalies. Mothers with amniotic sheets had a substantial incidence of previous spontaneous or therapeutic abortions.

Adolescent↗
PubMed1990

Functional similarities of hepatic cystic and biliary epithelium: studies of fluid constituents and in vivo secretion in response to secretin.

Hepatic cysts are a frequent manifestation of autosomal dominant polycystic kidney disease, but little is known about their functional characteristics. The goals of our study were to define the composition of hepatic cyst fluid and to determine whether hepatic cysts secrete in response to intravenously administered secretin. We percutaneously punctured five hepatic cysts and one proximal renal cyst from six subjects with autosomal dominant polycystic kidney disease and one solitary hepatic cyst from a subject without autosomal dominant polycystic kidney disease. Most fluids had an electrolyte composition similar to serum. Fluid from all hepatic cysts had glutamyltranspeptidase concentrations above those found in serum [( cyst]/[serum] = 4.93 +/- 5.92), contained secretory component (the epithelial receptor for polymeric IgA) and had glucose concentrations less than 15 mg/dl. Fluid from both hepatic and renal cysts of subjects with autosomal dominant polycystic kidney disease, but not from the subject with the solitary hepatic cyst, demonstrated extensive changes in the electrophoretic mobility of several serum proteins. Initial intracystic pressures ranged from 16 to 40 cm H2O, were reduced 57% to 97% after aspiration of a portion of cyst fluid and were held constant during the secretion study. Within 8 min of the intravenous administration of secretin, secretion of fluid increased in two of three hepatic cysts and in the renal cyst. The electrolyte composition of cyst fluids was not altered by secretin. These data suggest that hepatic cystic epithelium has functional characteristics of biliary epithelium and that secretion by both hepatic and renal cysts may be hormonally regulated.

Aged↗
PubMed1990

Conservative management of cervical pregnancy with subsequent fertility.

The reported incidence of cervical pregnancies with subsequent fertility is extremely low. We report a case managed conservatively that allowed for future fertility, and ultimately the delivery of a viable infant at term. The conservative management and a review of the literature are discussed.

Adult↗
PubMed1990

Prostate cancer: comparison of pre-operative 0.35 T MRI with whole-mount histopathology.

Magnetic resonance imaging of the prostate was performed in eight patients prior to radical prostatectomy. The results of the imaging studies were then directly compared to histopathologic findings from whole-mount histologic sections. Magnetic resonance imaging identified 82% of cancers greater than 5 mm in minimal diameter. Cancers were identified as areas of decreased signal intensity compared to the high signal intensity peripheral zone on long TR/TE sequences. Cancers were best detected when they involved the middle level of the gland and the posterior half of the prostate. Of the individual tumors identified by imaging, the amount of tumor involvement was underestimated by 37% and overestimated by 22% by MRI. We conclude that magnetic resonance imaging can identify prostate cancer, but has limitations as a screening modality and in accurately assessing the amount of involvement of the prostate gland by cancer.

Carcinoma↗
PubMed1990

Percutaneous cyst puncture in the treatment of cyst infection in autosomal dominant polycystic kidney disease.

Cyst infection in autosomal dominant polycystic kidney disease (ADPKD) poses a difficult diagnostic and therapeutic problem. We describe a serious indolent cyst infection due to Staphylococcus aureus, which was successfully diagnosed and treated with repeated percutaneous cyst drainage and intravenous (IV) antibiotic therapy. Cyst aspiration also permitted monitoring of cyst antibiotic levels and evidence of active infection.

Adult↗
PubMed1990

Quantitative CT of the spine. Significance of intervertebral body variability.

Quantitative CT of the spine has been used to predict and to identify a population at increased risk for fracture. This effort has been limited, in part, by the considerable range in normal values of mineral content. We studied the mineral contents of individual vertebral bodies to evaluate our empirical observation that mineral content changes from one vertebral body to the next and to assess the effect of this variability upon mineral content determination. Fifty-nine patients referred for the evaluation of osteoporosis were studied by single energy and dual energy quantitative CT. Variability among patients and fluctuations in the CT machine were corrected by a bone density phantom. Measured bone mineral contents were normalized by taking these variations into account. Analysis of covariance and t-tests indicated significant differences in the measured mineral contents from the T12 to the L3 vertebral bodies. Mean mineral contents for different vertebra were significantly different for both the single energy and dual energy methods, decreasing from T12 to L3. The measured mineral contents of the vertebral bodies within a given patient were highly correlated. The high correlation of the mineral contents of the vertebral bodies within a given patient strengthens the conclusions that individual vertebral content measurement is a valid predictor for the mineral content of vertebrae. The current method of averaging several vertebral bodies improves the reliability of an overall measurement of mineral content.

Adult↗
PubMed1990

Liver-lesion tissue contrast on MR images: effect of iron oxide concentration and magnetic field strength.

This study assessed the enhancement of liver-lesion contrast by using low levels of iron oxide contrast agent at four common magnetic resonance (MR) imaging field strengths: 0.15, 0.35, 0.5, and 1.5 T. Adenocarcinomas were percutaneously inserted into the livers of 15 rats. Iron oxide was given intravenously in concentrations of 0 (control group), 2.5, 5, 10, and 20 mumol/kg to three rats in each concentration group. All images were acquired between 1 and 24 hours after injection. Liver-lesion contrast ratios and contrast-to-noise ratios (C/Ns) were calculated. Results showed increased liver-lesion contrast and C/Ns with increased iron oxide concentration up to 10-20 mumol/kg at all four magnetic field strengths. At 0.15 T, iron oxide produced lower gains in tumor-liver contrast. At middle and high magnetic field strengths, liver-lesion contrast was similar for each level of iron oxide concentration, but C/Ns were markedly higher at 1.5 T than at middle field strength. Low levels of iron oxide contrast agent are effective at magnetic field strengths of 0.35 T and above, producing the greatest increase in C/N at middle field strengths.

Animals↗
PubMed1990

Prostatic comedocarcinoma: correlation of sonograms with pathologic specimens in three cases.

A unique sonographic appearance that correlates with comedocarcinoma of the prostate is described. The hard-copy and videotaped transrectal sonograms obtained in 27 patients before radical prostatectomy were reviewed. In three, the sonograms had a distinctive appearance characterized by a hypoechoic lesion containing stippled areas of hyperechogenicity. This was not present in the other 24. The sonograms of all 27 patients were compared with whole-mount histopathologic sections of the radical prostatectomy specimens. This comparison showed that the distinctive sonographic abnormalities in these three patients were caused by foci of comedocarcinoma, an aggressive variant of prostatic carcinoma (Gleason pattern 5). In none of the other 24 patients were similar sonographic findings seen and none had comedocarcinoma at histopathologic examination. These findings suggest that a hypoechoic lesion containing diffuse, stippled echogenicity may be a sonographic sign of comedocarcinoma.

Aged↗