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J R Thornbury

Publications and source records attributed to J R Thornbury.

At least 19 recordsLinked to original sources
PubMed2000

Prostate cancer staging: should MR imaging be used?--A decision analytic approach.

PURPOSE: To determine the appropriate use of magnetic resonance (MR) imaging for preoperative staging of prostate cancer. MATERIALS AND METHODS: Literature review was performed by using the principles of evidence-based medicine and medical technology assessment. A decision analytic model was used to compare (a) the strategy that radical prostatectomy is performed on the basis of clinical staging with (b) the strategy that extracapsular disease detected at MR imaging contraindicates radical prostatectomy in patients who were considered surgical candidates on the basis of clinical staging. RESULTS: After review of the literature, expert panel opinion did not recommend MR staging. No studies in which therapeutic efficacy was addressed were found. The decision analytic model indicated that the strategy including MR staging decreased costs (MR imaging, $10,568; radical prostatectomy, $11,669) and resulted in almost equal life expectancy (MR imaging, 12.59 years; radical prostatectomy, 12.60 years) and quality-adjusted life-years ([QALYs] MR imaging, 12.53; radical prostatectomy, 12.52). Results of sensitivity analyses demonstrated that the MR strategy was both more effective and less costly if the prior probability of extracapsular disease was at least 39% when considering QALY and 50% when considering unadjusted life expectancy. CONCLUSION: It is not yet conclusively determined whether preoperative MR staging is appropriate, but results of decision analysis suggest that MR staging is cost-effective for men with moderate or high prior probability of extracapsular disease.

Contraindications↗
PubMed1999

Intermediate outcomes: diagnostic and therapeutic impact.

The conceptual basis for intermediate outcomes has been established, and scientifically sound methods are available for assessment of these short-term outcomes. While modest intermediate outcomes research experience assessing imaging technology has accumulated in the literature, much more remains to be done, for the benefit of both patients and physicians. I would recommend that intermediate outcomes research become more focused on assessment earlier in the diffusion phase of imaging technology development. These studies should be based on traditional diagnostic accuracy studies, but these should be extended to include well-designed, high scientific quality treatment impact studies. Furthermore, such studies need to be multidisciplinary and multiinstitutional/multisite and include patient utility assessment components.

Attitude to Health↗
PubMed1997

Dynamic TurboFLASH subtraction technique for contrast-enhanced MR imaging of the prostate: correlation with histopathologic results.

PURPOSE: To assess whether a TurboFLASH (fast low-angle shot) magnetic resonance (MR) sequence can improve the accuracy of fast spin-echo (SE) endorectal coil MR imaging in the staging and localization of prostate cancer. MATERIALS AND METHODS: In 57 patients with prostate cancer, MR imaging was performed with the following sequences: T1-weighted SE, T2-weighted fast SE, single-section gadolinium-enhanced dynamic subtracted TurboFLASH (one image every 1.25 or 2.5 seconds), and late-phase gadolinium-enhanced T1-weighted SE. Retrospectively, two blinded independent readers graded onset and steepest slope of enhancement and assessed tumor involvement and capsular penetration. MR findings were correlated with histopathologic results. RESULTS: On TurboFLASH images, prostate cancer was characterized by early and rapidly accelerating enhancement compared with that of surrounding tissues. Average sensitivity, specificity, and accuracy for detection of tumor involvement for the two readers with TurboFLASH images were 73.5%, 81.0%, and 77.5%. These values with fast SE images were 57.5%, 80.5%, and 72.0%. Depiction of capsular penetration and delineation and staging of tumor were better when TurboFLASH images were included with fast SE images. Differences between the two sequences, however, were not statistically significant. CONCLUSION: Because the TurboFLASH sequence did not statistically significantly improve tumor localization and staging results, routine use is not recommended. The technique may be useful for selected patients with equivocal evidence of capsular penetration.

Aged↗
PubMed1996

A randomized comparison of iodixanol and iohexol in adult body computed tomography scanning.

RATIONALE AND OBJECTIVES: We compared the safety and imaging efficacy of iodixanol-270 (270 mg I/ml), iodixanol-320 (320 mg I/ml), both of which are isosmolal to blood, and iohexol-300 (300 mg I/ml) for body computed tomography (CT) scanning. METHODS: One hundred twenty-six patients from the University of Wisconsin Hospital and Temple University Hospital scheduled to undergo body CT examinations were randomly assigned to receive either iodixanol-270, iodixanol-320, or iohexol-300. Patients were monitored with questioning and vital signs before injection, immediately after injection, and at 24 and 48 hr. Extensive laboratory evaluation also was performed. RESULTS: No serious reactions or deaths occurred in any group. The occurrence of overall minor adverse events (usually warmth, headache, taste distortion, rash) was similar for the different groups. Laboratory results showed no significant difference across groups. There was no significant difference in image quality detected among groups. CONCLUSION: There was no detectable difference in safety and imaging efficacy among the three contrast groups in this study. However, patients from the University of Wisconsin experienced significantly less injection discomfort with iodixanol-270 than with iohexol-300. Large clinical studies may more definitively determine the presence and nature of the relative advantages of iodixanol compared with currently available ionic and nonionic contrast agents.

Contrast Media↗
PubMed1996

Local staging of prostate cancer with endorectal MR imaging: correlation with histopathology.

OBJECTIVE: To evaluate the accuracy of MR imaging of the prostate with an endorectal surface coil in determining presence, localization, volume, and local stage of prostate carcinoma. SUBJECTS AND METHODS: MR images of 34 patients with biopsy-proven cancer were correlated retrospectively with the histologic mappings of radical prostatectomy specimens. The volume and number of tumor lesions of MR images were calculated and compared with the surgical specimens used as the gold standard. Tumor stage based on MR imaging was compared with the pathologic stage according to the TNM classification. Predictive values were calculated separately for all lesions and for the lesions correctly localized with MR imaging. RESULTS: MR imaging correctly depicted the location of 67% of the tumors. Twenty percent of the lesions depicted by MR imaging appeared to be false-positive errors. The tumors that were missed were located centrally and ventrally in the prostate. Tumor volume as shown by MR imaging was within a 25% range of the actual tumor volume in 10 cases, overestimated in 16 cases, and underestimated in eight cases. Histopathology showed capsular penetration in 12 of 34 patients (35%) and in 14 of 52 lesions (27%). Sensitivity, specificity, and positive predictive values were 43%, 84%, and 55%, respectively. Histologically, capsular penetration extended less than 1 mm into the periprostatic adipose tissue in seven patients. Sensitivity for capsular penetration less than 1 mm was 14%. Sensitivity for capsular penetration more than 1 mm was 71%. Accuracy for differentiating a pT2 from a pT3 tumor was 68%. CONCLUSION: Results from this study indicate that the accuracy of the technique was not satisfactory for predicting actual tumor volume. Tumor detection and localization was more accurate in the peripheral zone than in the central zone. Accuracy was poor for detecting capsular penetration of less than 1 mm, but accuracy was much better for penetration of more than 1 mm. Because recent reports suggest that capsular penetration of less than 1 mm does not adversely affect surgical cure, MR imaging still may be practical in the selection of patients for radical prostatectomy.

Adenocarcinoma↗
PubMed1994

Eugene W. Caldwell Lecture. Clinical efficacy of diagnostic imaging: love it or leave it.

The traditional goal of radiology has been to provide images of the highest technical quality that permit the most accurate diagnoses possible. From a more global perspective, diagnostic radiology is part of a larger system that has as its goal effective and efficient treatment of patients. A six-tiered hierarchical model of efficacy that includes this more global view is presented. This model is intended to improve understanding of the continuum that efficacy is and to conceptually relate efficacy to technology assessment and outcome research. Better understanding of efficacy/technology assessment and outcome research fostered by the model should encourage radiologists to participate actively in federally supported research in these areas. Those radiologists who do so will come to understand better how radiology can help patients and society as a whole. Use of the model's concepts should also aid radiologists in becoming more effective consultants to their clinical colleagues about optimal use of high-technology imaging from the perspectives of clinical efficacy, patient outcome, and societal efficacy.

Cost-Benefit Analysis↗
PubMed1994

Why should radiologists be interested in technology assessment and outcomes research?

Why should radiologists be interested in technology assessment and outcomes research? The primary answer relates to optimizing the use of imaging examinations in daily practice such that this results in the most effective, efficient, and highest quality patient care possible. In formal outcomes research, this is measured in terms of quality of life and perceptions of patients' well-being. Thus, the primary answer is that radiologists need to become better informed and knowledgeable about research methods and be able to critically review the results in the literature of technology assessment and outcomes research regarding the use of imaging examinations. This will enable radiologists to become more effective consultants for their referring physician colleagues by optimizing the use of imaging examinations to affect patient outcomes. Radiologists also will be more effective participants in guidelines task force groups.

Forecasting↗
PubMed1993

MR imaging of adrenal lymphoma.

A case of lymphoma of the adrenal glands is presented. Both computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated large bilateral adrenal masses with no other associated abdominal abnormalities. MR was better able to demonstrate inferior vena caval patency than CT, and effectively exclude pheochromocytoma as a differential diagnostic consideration due to signal characteristics of the masses.

Adrenal Gland Neoplasms↗
PubMed1993

Disk-caused nerve compression in patients with acute low-back pain: diagnosis with MR, CT myelography, and plain CT.

Ninety-five patients with acute low-back and radicular pain underwent magnetic resonance (MR) imaging and either plain computed tomography (CT) (n = 32) or CT myelography (n = 63) for diagnosis of herniated nucleus pulposus-caused nerve compression (HNPNC). Patients were followed up for at least 6-12 months. Fifty-six patients underwent surgery, and 39 received conservative treatment. Receiver operating characteristic (ROC) analysis was performed on correlation of results of blinded image reading with "true" diagnoses determined by an expert panel [corrected]. Results in subgroup analysis for ROC curve areas were MR, 0.84, versus plain CT, 0.86; MR, 0.81, versus CT myelography, 0.83; and MR, 0.82, versus findings with both CT techniques, 0.85. Results indicate no statistically significant difference in diagnostic accuracy of HNPNC among the three modalities. Thus, factors of cost, radiation dose, and invasiveness influence selection of modality. On the basis of accuracy findings, the authors suggest that MR should replace CT myelography because of the invasiveness of myelography but that MR should not replace plain CT because plain CT is equally accurate and much less costly.

Acute Disease↗
PubMed1991

Acute renal infections.

The current status of the pathogenesis of the disease and imaging methods in acute renal infections is reviewed. The spectrum of type of infection includes 1) acute pyelonephritis, 2) acute bacterial nephritis, 3) acute renal abscess, 4) acute pyonephrosis, and 5) infected renal simple cyst. The two most common imaging methods used are ultrasound and computed tomography (CT). Recent experience from the literature suggests that CT offers some advantages over ultrasound particularly in distinguishing degree and type of involvement of the renal parenchyma and in more accurate diagnosis of acute abscess.

Abscess↗
PubMed1991

Nonpalpable cancer of the prostate: assessment with transrectal US.

Palpable cancer of the prostate is widely believed to be clinically significant. The authors compared the clinical significance of palpable prostate cancer with nonpalpable prostate cancer discovered with transrectal ultrasound (US). A strong association between lesion volume measured with preoperative transrectal US and volumetric measurements in 60 radical prostatectomy specimens permitted the use of tumor size measured with transrectal US as a reasonable estimation of gross tumor volume. In a subsequent clinical series, 147 biopsy-proved cancers were grouped according to size measured at US, the findings at digital rectal examination (DRE), and the Gleason score. For the 147 patients with known prostate cancer, a statistically significant difference between Gleason scores of palpable and nonpalpable cancers could not be demonstrated when the size of the tumor and its location within the prostate were held constant. Assuming that the Gleason score is a reliable indication of malignant potential and clinical significance, the authors conclude that nonpalpable prostatic cancer detected with transrectal US alone may be just as clinically significant as prostatic cancer discovered with DRE.

Biopsy, Needle↗
PubMed1989

Intravenous pyelography: the case against its routine use.

PURPOSE: To critically appraise four common uses of intravenous pyelography in adults. DATA IDENTIFICATION: We reviewed the literature on the use of intravenous pyelography for four clinical indications. STUDY SELECTION: We analyzed the literature to determine the proportion of intravenous pyelograms producing clinically useful information (yield) in four clinical situations. The best estimate of its accuracy (sensitivity and specificity) for associated pathologic findings was determined. The implications of using the test on the outcomes of patients and costs were evaluated. RESULTS OF DATA SYNTHESIS: The yield of significant abnormalities in patients having prostatectomy is small; intravenous pyelography does not specifically indicate ureteral obstruction, and is not sensitive or specific enough for screening for urinary tract malignancies. Many false-positive results, little benefit, and significant costs can be expected. When used before hysterectomy, intravenous pyelography does not reduce injury to the ureters, and the yield of unexpected abnormalities is small. The use of the test to screen for unexpected anatomic abnormalities in adult women after urinary tract infections has not led to improved outcomes or prevention of impaired renal function. Acquired causes of obstruction will be suggested by the history or physical examination. In hypertensive adults, intravenous pyelography is not accurate enough in detecting renal artery stenosis or in predicting favorable outcomes of renal artery surgery. Also, large costs are generated by high false-positive rates, and candidates for successful surgery are not reliably identified. CONCLUSIONS: Selective use of intravenous pyelography is recommended for patients before prostatectomy or hysterectomy, in women after urinary tract infections, and in adults whose hypertension may have a renovascular cause. Use should be reserved for patients whose history and physical examination raise specific questions for which this test could provide an answer that would affect treatment.

Cost-Benefit Analysis↗
PubMed1989

MRI of carcinoma of the cervix.

The current status of the use of MRI in the identification and staging of carcinoma of the cervix will be reviewed emphasizing the positive and negative value of this imaging technology.

Carcinoma↗