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D J Rubens

Publications and source records attributed to D J Rubens.

36 records · Page 2Linked to original sources
PubMed1996

The prostate: decreasing cost-effectiveness of biopsy with advancing age.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the cost-effectiveness of prostate biopsy at different excess prostate-specific antigen (PSA) levels as a function of age. METHODS: Medical decision analysis was performed with standard software (SMLTREE) to determine marginal effectiveness in quality adjusted life years (QALYs) and marginal cost-effectiveness in dollars per QALY of immediate prostate biopsy at different excess PSA levels between 0 ng/mL and 20 ng/mL. The probability of clinically significant cancer with a positive biopsy (pD+Bx+) was assumed to decrease with age from 1.0 at age 50 to 0.2 at age 70. Costs were based on charges at our hospital and were considered over a 2-year time frame. RESULTS: With our base case assumptions there was a decrease in QALYs and an increase in costs doing an immediate prostate biopsy at all excess PSA levels between 0 ng/mL and 20 ng/mL, compared with not biopsying the prostate at > or = 70 years. Doubling pD+Bx+ from 0.2 to 0.4 in the 70-and-older age group resulted in a small increase in QALYs in biopsying the prostate at excess PSA levels between 0 ng/mL and 20 ng/mL. However, the marginal cost-effectiveness of prostate biopsy was very high, ranging from $275,000/QALY biopsying at an excess PSA level of 0 ng/mL to $68,000/QALY biopsying at an excess PSA level of 20 ng/mL. This compared with it being more effective and less costly to biopsy at all excess PSA levels > or = 0 ng/mL in 50-year old patients. CONCLUSION: Immediate prostate biopsy is not cost-effective and can be detrimental in patients > or = 70 years of age at all excess PSA levels between 0 ng/mL and 20 ng/mL.

Aged↗
PubMed1996

Clinical evaluation of prostate biopsy parameters: gland volume and elevated prostate-specific antigen level.

PURPOSE: To determine whether excess prostate-specific antigen (PSA) improves the accuracy of predicting positive biopsy results. MATERIALS AND METHODS: Results of prostate biopsy in 130 consecutive patients were correlated with transrectal ultrasound (TRUS) findings, digital rectal examination results, serum PSA level, and excess PSA (serum PSA level minus predicted PSA level [prostate volume x 0.12]), alone and in combination. Random sextant biopsy was performed in all patients, as well as directed biopsy of any suspicious lesion seen at TRUS. RESULTS: Excess PSA alone was most accurate in the prediction of positive biopsy results. Use of an excess PSA of > or = 0 ng/mL instead of a serum PSA level of > 4 ng/mL to initiate prostate biopsy increased the positive yield from 49% to 56% and accuracy from 51% to 62%, eliminating 21% of biopsies while maintaining sensitivity at 94% (vs 95% with serum PSA level). CONCLUSION: Use of only excess PSA of > or = 0 ng/mL to initiate prostate biopsy results in the best combination of sensitivity and specificity compared with the other standard parameters.

Aged↗
PubMed1995

Primary lymphoma of bone. Correlation of magnetic resonance imaging features with cytokine production by tumor cells.

BACKGROUND: Primary lymphoma of bone is a rare, aggressive neoplasm that can present with a large, soft-tissue mass despite minimal evidence of cortical destruction on plain radiographs. METHODS: High resolution magnetic resonance imaging (MRI) examinations of four patients with primary lymphoma of bone were reviewed retrospectively, and in each case intramedullary tumors demonstrated "penetrating channels" extending through the cortex. The MRI studies were correlated with the histopathologic assessment of the tumor for each patient. Immunohistochemistry was performed for immunophenotyping and for cytokine expression by tumor cells. The cytokines that were investigated were interleukin-1, interleukin-6, and tumor necrosis factor-alpha, molecules known to regulate osteoclastic activity. RESULTS: The linear cortical foci noted on MRI correlated with the histopathologic findings of tumor-associated cutting cones, in proximity to osteoclastic bone resorption. Immunohistochemical stains showed a B-cell phenotype for each tumor and positive immunoreactivity in tumor cells for cytokine mediators that stimulate osteoclastic activation. CONCLUSIONS: These findings indicate that the tumor cells in these cases produce soluble cytokine mediators that may regulate extensive osteoclastic activity. In primary lymphoma of bone, tumor activation of osteoclastic resorption, with production of tumor tunnels through the cortex, may represent one of the mechanisms by which lymphoma escapes the intramedullary space and forms large, soft-tissue masses without extensive cortical destruction.

Adult↗
PubMed1995

Effect of a main renal artery stenosis on the downstream Doppler waveform in dogs.

RATIONALE AND OBJECTIVES: We evaluated the changes in the down-stream Doppler waveforms caused by a proximal stenosis in the main renal artery of dogs. METHODS: Renal parenchymal arterial waveforms downstream from mild (< 50%), moderate (50-75%), and severe (76-95%) stenoses were compared with nonstenotic baseline waveforms in five mongrel dogs. Waveform shapes were categorized as biphasic or monophasic. The percentage of biphasic and monophasic waveforms was determined for each stenosis. The acceleration index (AI) and the acceleration time (AT) were determined using traditional and modified calculations (AI' and AT'). Late systolic deceleration (DS), diastolic deceleration (DD), and the resistive index (RI) also were measured. RESULTS: AT, AI', and AT' demonstrated significant differences between the severe stenoses and nonstenotic baselines (p < .05); however, there was no difference between the mild and moderate stenoses versus baselines. The percentage distribution of monophasic and biphasic waveforms was highly correlated with the degree of stenosis. Monophasic waveforms increased on average from 22.5% of baseline waveforms to 76.5% of waveforms in the severe stenoses. Biphasic waveforms decreased on average from 69.9% of baseline waveforms to 18.7% of waveforms in the severe stenoses. CONCLUSION: Quantitative evaluation of the downstream waveform parameters (AI, AT, AI', AT', DS, DD, and RD in the dog kidney is not sufficiently accurate, but calculation of the percentage of the monophasic and biphasic waveforms present may be useful to predict a hemodynamically significant renal artery stenosis (> or = 50%).

Animals↗
PubMed1995

Sonoelasticity imaging of prostate cancer: in vitro results.

PURPOSE: To compare sonoelasticity imaging versus ultrasound (US) in detection of prostate cancer. MATERIALS AND METHODS: Sonoelasticity imaging and US were performed on 10 prostatectomy specimens in which cancer was detected at previous biopsy. Six patients had no palpable lesions at digital rectal examination. Specimens were imaged axially at the apex, middle, and base of the gland to correlate with location of pathologic sections. All images were interpreted blindly and prospectively, and results were compared with pathologic findings. RESULTS: Sensitivity and specificity with sonoelasticity imaging were 85% and 84%, respectively, and 30% and 100% with standard US when compared with pathologic findings. Sixty-four percent of pathologically confirmed tumors detected at sonoelasticity imaging were isoechoic on conventional US images. CONCLUSION: In this limited study, sonoelasticity imaging was more sensitive for tumor detection and more accurate for assessment of tumor location than was conventional US.

Adenocarcinoma↗
PubMed1995

Hypoechoic fat: a sonographic pitfall.

Fat has classically been described as hyperechoic on sonograms because of its acoustic impedance relative to surrounding tissue, although certain types of fat in certain anatomic locations can be hypoechoic. Examples in the literature include hypoechoic fat in and around the kidneys as well as in ovarian neoplasms [1-3]. We present several cases of hypoechoic fat collections in various anatomic locations to illustrate the importance of its presence and to minimize the number of erroneous diagnoses.

Abdominal Muscles↗
PubMed1993

Rheumatoid arthritis: evaluation of wrist extensor tendons with clinical examination versus MR imaging--a preliminary report.

To determine whether magnetic resonance (MR) imaging can improve assessment of the extensor tendons of the wrist and their propensity to rupture, the dorsal tendons in 23 wrists in 20 patients with rheumatoid arthritis were clinically assessed and then examined with MR imaging. Clinical and MR imaging evaluations were performed blindly and independently. The six extensor tendon compartments were assessed with MR imaging for presence of pannus, synovial effusion, and tendon involvement or rupture. Clinical scores of systemic disease, dorsal tendon sheath swelling, and risk of tendon rupture ranged from 0 to 3 in each category; the overall score was not associated with any MR imaging category. Clinical assessment of enlargement of the dorsal tendon sheath and clinical risk of rupture correlated poorly with findings on MR images. All eight wrists with clinically minimal risk of rupture had pannus, effusions, and tendon involvement on MR images; the findings were similar in the wrists with moderate (grade 2) risk of rupture. MR imaging depicts involvement of the dorsal tendon sheath and dorsal tendons that cannot be assessed with other radiologic or clinical means.

Adult↗
PubMed1993

Intrinsic and extrinsic carpal ligaments: evaluation by three-dimensional Fourier transform MR imaging.

OBJECTIVE: As evaluation of the anatomic and functional integrity of intrinsic and extrinsic carpal ligaments with conventional imaging methods is difficult, we designed a study to evaluate the ability of three-dimensional Fourier transform MR imaging to show the carpal ligaments. SUBJECTS AND METHODS: We obtained coronal MR images of 15 cadaveric wrists and 15 wrists of patients, using three-dimensional volume acquisition with a gradient-recalled echo sequence and a 1.5-T magnet. The MR findings were compared with the findings on dissection in the 15 cadaveric wrists and with the surgical findings in eight patients. RESULTS: All the volar ligaments had a striated appearance on MR images, with alternating bands of low and intermediate signal intensity. No tears of the extrinsic ligaments were seen. The intrinsic scapholunate and lunotriquetral ligaments were seen as structures with more homogeneously intermediate intensity attaching to their adjacent bone through high-signal-intensity hyaline cartilage. For the cadaveric wrists, MR indications of a tear of the scapholunate ligament were true-positive in three and false-negative in three; indications of a tear of the lunotriquetral ligament were true-positive in five, false-positive in two, and false-negative in one. For the eight patients with surgical confirmation, the MR findings regarding tears were true-positive in two and true-negative in six. Neither surgery nor MR imaging showed any tears of the scapholunate ligament. CONCLUSION: Three-dimensional Fourier transform MR imaging with thin slices provides the resolution necessary to visualize the anatomic detail of the extrinsic and intrinsic ligaments of the wrist, but additional clinical experience with this technique will be required to determine its diagnostic capabilities.

Carpal Bones↗
PubMed1987

Magnetic resonance imaging and pathologic correlation in stage IB cervix cancers.

Ten patients with Stage IB cervical carcinoma underwent primary radical surgery within 2 weeks following magnetic resonance imaging (MRI) examination. Underestimation of stromal disease was common on examination under anesthesia (EUA), while MRI correctly estimated tumor volume and degree of stromal invasion in 9 of 10 cases. In six patients, EUA severely underestimated the tumor: stroma ratio, and five of these six underwent postoperative pelvic radiation therapy. Had the true extent of tumor involvement been recognized preoperatively, we probably would have selected either primary radiation or radiation plus extrafascial hysterectomy for these patients. Pathologic correlation revealed that MRI more accurately predicted tumor size and extent of stromal involvement than clinical examination. We believe that magnetic resonance imaging may have a role in treatment planning of patients with Stage IB cervical carcinoma.

Adult↗
PubMedDate not supplied

Sonography: a useful tool to detect the mechanical causes of renal transplant dysfunction.

PURPOSE: The purpose of this study was to evaluate the utility of sonography in distinguishing between mechanical and nonmechanical causes for renal transplant dysfunction. METHODS: We reviewed all ultrasound examination reports (n = 286) for 63 consecutive patients who received 64 renal transplants. We assessed the sensitivity and specificity of different degrees of hydronephrosis (mild, moderate, or severe) in detecting urinary tract obstruction; different volumes of new or increasing peritransplant fluid in detecting urine leaks; different total volumes of peritransplant fluid in predicting significant compression of the transplant; and Doppler vascular criteria for predicting arterial and venous occlusion. RESULTS: All mechanical complications were detected (100% sensitivity) with specificities of 91.9% for ureteral obstruction (criterion, moderate hydronephrosis), 83.4% for urine leaks (criterion, any new fluid or any increase), 91.4% for fluid collections that compressed the transplant (criterion, > 100 ml), and 100% for vascular occlusion (criteria, no flow for arterial occlusion; no venous flow and reversal of arterial flow during diastole for venous occlusion). CONCLUSIONS: Sonography is very useful in distinguishing between mechanical and nonmechanical causes for renal transplant dysfunction. It has high sensitivity and acceptable specificity in this setting.

Adolescent↗
PubMedDate not supplied

Testicular epidermoid cysts: sonographic features with histopathologic correlation.

Testicular epidermoid cysts are rare, accounting for 1% of all testicular tumors. We present the sonographic appearances of epidermoid cysts in 3 cases, together with the histopathologic correlation. In case 1, sonography showed an intratesticular hypoechoic mass with a well-defined echogenic rim; the mass measured 1.8 x 1.5 x 1.5 cm, and there was no evidence of calcification. In case 2, sonography showed a well-circumscribed mass measuring 1.3 x 1.3 x 1.0 cm, with alternating hypoechoic and hyperechoic rings (onion-ring appearance) and no calcifications. In case 3, sonography showed a 2.4- x 2.3- x 2.3-cm, well-circumscribed, oval mass with a heterogeneous echotexture and an outer hypoechoic halo. The mass contained plaque-like regions of increased echogenicity, with peripheral acoustic shadowing from refraction artifact. Hypoechoic clefts were visualized posterior to the plaque-like areas. The triad of findings-sonographic appearance of an onion ring, avascularity on Doppler sonography, and negative results of tumor marker studies-is highly suggestive of an epidermoid cyst.

Adult↗
PubMedDate not supplied

Delayed computed tomographic characterization of renal masses: preliminary experience.

BACKGROUND: To evaluate the performance of delayed contrast enhanced computed tomography (DCT) in characterizing renal masses. METHODS: Twenty-four patients with suspected renal masses or indeterminate renal masses on previous imaging studies were prospectively evaluated with preintravenous contrast imaging, conventional contrast-enhanced computed tomography (imaging initiated 2 min after intravenous contrast injection), and DCT (imaging initiated 13 min after injection of intravenous contrast). Only lesions larger than 1.0 cm were evaluated, with scanning parameters kept constant across the three scans. RESULTS: All pathologically confirmed renal cell carcinomas (n = 6) were detected on DCT using a threshold attenuation decrease of 10 Hounsfield units (HU). A significant decrease (p = 0.031) in attenuation occurred in renal cell carcinomas (mean = 29.6 +/- 23.6 HU) compared with the attenuation change (mean decrease = 1.1 +/- 7.1 HU), which occurred in non-neoplastic renal cysts (n = 34). Non-neoplastic renal cysts were correctly classified by DCT 32 of 34 times (94%). CONCLUSIONS: In this study, DCT distinguished renal cell carcinomas from non-neoplastic cysts in a vast majority of cases and may aid in characterizing incidentally discovered renal lesions on postcontrast CT.

Adenoma↗
PubMedDate not supplied

Urine leaks in renal transplant patients. Diagnostic usefulness of sonography and renography.

We evaluated the utility of sonography and nuclear medicine renography in the detection of urine leaks in 57 renal transplant patients. Sonography and renography were equally sensitive in detecting leaks. But renography was more specific and therefore accurate (p < 0.0001) in detecting leaks. Urine leaks should be considered on sonography, which is often the first imaging study ordered in evaluating renal transplants, with new or increasing peritransplant fluid collections. Leaks should be confirmed by renography before performing additional invasive radiologic or surgical procedures.

Adolescent↗