Search PubMed⌕ Search

Biomedical subjects

H Hricak

Publications and source records attributed to H Hricak.

At least 73 records · Page 4Linked to original sources
PubMed1998

Preoperative staging of cervical carcinoma: phased array coil fast spin-echo versus body coil spin-echo T2-weighted MR imaging.

OBJECTIVE: This study was performed to compare the diagnostic efficacy of MR imaging in the preoperative evaluation of invasive cervical cancer using the pelvic phased array coil in combination with fast spin-echo T2-weighted imaging and the body coil in combination with conventional spin-echo T2-weighted imaging. MATERIALS AND METHODS: Ninety-four women (22-68 years old) with invasive cervical cancer underwent MR imaging (at 1.5 T) using a body coil conventional spin-echo protocol (n = 62) or a phased array coil fast spin-echo protocol (n = 32). Imaging preceded surgery by no more than 5 weeks. MR images were evaluated for tumor size, local stage, and nodal metastasis using surgical pathology as the standard of reference. RESULTS: Overall staging accuracy for the body coil conventional spin-echo protocol (89%) was not significantly different from that of the phased array coil fast spin-echo protocol (91%). Both techniques also achieved similar accuracy in diagnosing parametrial invasion (95% versus 94%) and lymph node metastases (85% versus 91%) and in tumor sizing (correlation coefficient, .93 versus .94). CONCLUSION: In the preoperative staging of cervical carcinoma by MR imaging, both the newer (phased array coil fast spin-echo protocol) and the older (body coil conventional spin-echo protocol) techniques achieved similarly high accuracies in local staging, assessment of parametrial invasion, and evaluation of tumor size. Decreased imaging time and increased image resolution are advantages of the newer technique, although in our series they did not increase staging accuracy.

Adult↗
PubMed1997

Radiological evaluation of lymph node metastases in patients with cervical cancer. A meta-analysis.

OBJECTIVE: To apply meta-analysis to compare the utility of lymphangiography (LAG), computed tomography (CT), and magnetic resonance (MR) imaging for the diagnosis of lymph node metastasis in patients with cervical cancer. DATA SOURCES: MEDLINE literature search and manual reviews of article bibliographies. STUDY SELECTION: Studies selected included at least 20 patients with imaging-histologic correlation, described diagnostic criteria for lymph node metastasis, and presented data to allow calculation of contingency tables. DATA EXTRACTION: Independently by 2 investigators, stratified for stage of disease (early vs late) and for lymph node location (pelvic vs para-aortic). DATA SYNTHESIS: Seventeen studies met the inclusion criteria for LAG, 17 for CT, and 10 for MR imaging. Summary receiver operator characteristic analysis showed no significant differences in the overall performance of LAG, CT, and MR imaging. There was, however, a trend toward better performance for MR imaging than for LAG or CT, both globally and when stratified for stage of disease or for lymph node location. Bayesian analysis of clinical utility showed only moderate increases in positive posttest probability of lymph node metastasis for all methods. Negative test results had a greater impact and, depending on the clinical setting, decreased the probability of lymph node metastasis from 15% to 44% (pretest) to 3% to 18% (posttest). CONCLUSIONS: The LAG, CT, and MR imaging perform similarly in the detection of lymph node metastasis from cervical cancer. As CT and MR imaging are less invasive than LAG and also assess local tumor extent, they should be considered the preferred adjuncts to clinical evaluation of invasive cervical cancer.

Female↗
PubMed1997

Plexiform neurofibroma involving the genitourinary tract in children: case reports and review of the literature.

We report extensive genitourinary neurofibroma in two children who presented with massive bilateral hydroureteronephrosis and a thick-walled bladder. The best radiologic technique to stage the disease and determine treatment is magnetic resonance imaging. Management of extensive genitourinary neurofibroma is controversial. Based upon our experience and a review of the literature, aggressive surgery should be approached cautiously.

Humans↗
PubMed1997

Detection of extracapsular extension of prostate carcinoma with endorectal and phased-array coil MR imaging: multivariate feature analysis.

PURPOSE: To determine which magnetic resonance (MR) imaging features are most predictive of extracapsular extension of prostate carcinoma. MATERIALS AND METHODS: In 77 patients who had stage pT2 or pT3 prostate carcinoma, MR images were retrospectively reviewed by three readers with varying experience in interpretation of endorectal coil images of the prostate gland. MR imaging features assessed were broad tumor contact, smooth capsular bulge, irregular bulge, obliteration of the rectoprostatic angle, and asymmetry of the neurovascular bundle. Multivariate logistic regression analysis was performed to determine the relative value of each MR imaging feature. RESULTS: At multivariate analysis, obliteration of the rectoprostatic angle and asymmetry of the neurovascular bundle were most predictive of extracapsular extension, with a specificity of up to 95% and sensitivity of 38%. Poor-quality images reduced accuracy for all readers. The most experienced reader demonstrated overall accuracy of 77% in determination of extracapsular extension. CONCLUSION: Obliteration of the rectoprostatic angle and asymmetry of the neurovascular bundle were most indicative of extracapsular extension. Reader experience plays an important role in the ability to interpret prostate MR images and is an important contributor to interobserver variability.

Aged↗
PubMed1997

Primary amenorrhea: evaluation with MR imaging.

PURPOSE: To determine the accuracy of magnetic resonance (MR) imaging in the evaluation of patients with a history of primary amenorrhea. MATERIALS AND METHODS: Twenty-nine patients with primary amenorrhea underwent T2-weighted MR imaging in the axial and sagittal planes. Contrast material-enhanced and unenhanced T1-weighted MR imaging was performed in selected cases. MR imaging findings were correlated with surgical findings in 23 patients and with clinical findings in six patients. RESULTS: Surgical correlation was available in 14 of 17 patients with female anatomic anomalies (Mayer-Rokitansky-Küster-Hauser syndrome [n = 9], transverse vaginal septum [n = 3], imperforate hymen [n = 1], cervical agenesis [n = 1]), which confirmed MR imaging findings. In nine of 12 patients with congenital disorders of sexual differentiation (testicular feminization [n = 5], true hermaphrodite [n = 2], gonadal dysgenesis [n = 2]) who underwent surgical correlation, 13 of 16 (81%) gonads were correctly localized with MR imaging. Overall, there was excellent correlation between the classification of patients with MR imaging versus classification with the combination of surgical and laboratory findings (K = 0.88). CONCLUSION: MR imaging is useful in the work-up of patients who present with primary amenorrhea both for accurate diagnosis of pathologic conditions and for surgical planning.

Adolescent↗
PubMed1996

Prostate volumes defined by magnetic resonance imaging and computerized tomographic scans for three-dimensional conformal radiotherapy.

PURPOSE: To compare the prostate volumes defined on magnetic resonance imaging (MRI), and noncontrast computerized tomographic (CT) scans used for three-dimensional (3D) treatment planning. METHODS AND MATERIALS: Ten patients were simulated for treatment using immobilization and a retrograde urethrogram. 3D images were used to compare prostate volumes defined by MRI (4-6 mm thick slices) and CT images (5 mm thick slices). Prostate volumes were calculated in cm(3) using the Scanditronix 3D planning system. MRI/CT images were merged using bony anatomy to define the regions of discrepancy in prostate volumes. RESULTS: The mean prostate volume was 32% larger (range-5-63%) when defined by noncontrast CT compared to MRI. The areas of nonagreement tended to occur in four distinct regions of discrepancy: (a) the posterior portion of the prostate, (b) the posterior-inferior-apical portion of the prostate, (c) the apex due to disagreement between a urethrogram based definition and the location defined by MRI, (d) regions corresponding to the neurovascular bundle. CONCLUSION: There is a tendency to overestimate the prostate volume by noncontrast CT compared to MRI. Awareness of this tendency should allow us to be to more accurately define the prostate during 3-D treatment planning.

Humans↗
PubMed1996

Detection of locally recurrent prostate cancer after cryosurgery: evaluation by transrectal ultrasound, magnetic resonance imaging, and three-dimensional proton magnetic resonance spectroscopy.

OBJECTIVES: To assess and compare the clinical usefulness of transrectal ultrasound (TRUS), magnetic resonance imaging (MRI), and three-dimensional proton magnetic resonance spectroscopic imaging (3-D MRSI) in detecting local recurrence of carcinoma of the prostate (CaP) in patients with detectable prostate-specific antigen (PSA) levels after cryosurgery. METHODS: In a prospective study, 25 patients who had undergone cryosurgery as primary treatment for CaP underwent endorectal MRI and 3-D MRSI, followed by TRUS-guided prostate biopsy. At the time of study, 20 patients had detectable PSA; the remaining 5 patients served as controls. All patients had random sextant and guided prostate biopsy for correlation with imaging and MR spectroscopic findings. RESULTS: In patients with detectable PSA, MRSI identified, location-for-location, all foci of CaP and benign prostatic tissue that were detected by prostate biopsy. MRSI identified more sites with CaP than did prostate biopsy, indicating a larger volume of cancer. In 2 patients with detectable PSA and negative prostate biopsy, MRSI identified 11 voxels with viable prostatic tissue. In patients with undetectable PSA, both MRSI and prostate biopsy showed necrosis. Ultrasound and MRI were very poor tools for identifying recurrent cancer and differentiating between viable and necrotic prostate tissue. CONCLUSIONS: 3-D MRSI is superior to TRUS and MRI in differentiating among CaP, BPH, and necrosis when local recurrence after cryosurgery is suspected. By providing chemical mapping of the prostate in contiguous voxels, the addition of spectroscopy to endorectal MRI increases the sensitivity for detection of local recurrence.

Aged↗
PubMed1996

Comparison of diagnostic studies in the pretreatment evaluation of stage Ib carcinoma of the cervix.

The results of our study highlight the need for change in the pretreatment workup of clinical stage Ib cervical cancer. The routine use of excretory urography, barium enema, cystoscopy,and sigmoidoscopy is not justified. MR evaluation is recommended in patients with lesions larger than 2 cm (the group with the greatest increase in predictive value). Although CT scanning is not recommended for the evaluation of parametrial invasion, both CT scanning and MR imaging provide similar positive and negative posttest probabilities for the evaluation of nodal disease.

Bayes Theorem↗
PubMed1996

Invasive cervical carcinoma: role of MR imaging in pretreatment work-up--cost minimization and diagnostic efficacy analysis.

PURPOSE: To examine the cost and efficacy of diagnostic work-up in patients with invasive cervical cancer. MATERIALS AND METHODS: In 246 patients with invasive cervical cancer, all diagnostic tests performed before treatment were recorded. Patients were divided into two groups: those who underwent magnetic resonance (MR) imaging as the initial study (n = 105) and those who did not (n = 141). A list of 1995 Medicare global payments was used to measure cost. Bayesian analysis (likelihood ratios derived from a literature search) was performed for bladder, rectal, parameterial, and nodal involvement in stage Ib disease. RESULTS: Significantly fewer procedures and fewer invasive studies were performed in the MR imaging group. Net cost savings for the MR imaging group was $401 for all patients and $449 for patients with stage Ib disease. For stage Ib disease, the 0% pretest probability of bladder or rectal invasion does not justify the routine use of barium enema examination, cystoscopy, or proctoscopy. The increase in predictive values for parameterial and nodal disease was highest for MR imaging when tumor size was at least 2 cm. CONCLUSION: Guidelines for the pretreatment work-up of clinical stage Ib cervical cancer need revision. MR imaging should be used as an adjunct to clinical evaluation.

Adenocarcinoma↗
PubMed1996

Three-dimensional H-1 MR spectroscopic imaging of the in situ human prostate with high (0.24-0.7-cm3) spatial resolution.

PURPOSE: To evaluate if three-dimensional hydrogen-1 magnetic resonance spectroscopic imaging (3D MRSI) when combined with a clinical MR imaging examination could discriminate prostatic adenocarcinoma from normal prostatic zonal anatomy and benign prostatic hyperplasia (BPH) on the basis of observable metabolite levels. MATERIALS AND METHODS: Combined phased-array, endorectal MR imaging and 3D MRSI was performed in nine young healthy volunteers, five patients with BPH, and 85 patients with prostate cancer and BPH. Volume MR imaging and 3D MRSI data were analytically corrected for the reception profile of the endorectal and pelvic phased-array coils, aligned with the MR imaging data, and compared with postoperative pathologic histology findings. RESULTS: Statistically significant variations in metabolite levels with prostatic zonal anatomy, age, and pathologic condition were detected with a 3D MRSI examination added to a clinical MR imaging examination. Significantly higher choline levels and significantly lower citrate levels were observed in regions of cancer compared with BPH and normal peripheral zone tissues. The ratio (choline + creatine/citrate) in regions of cancer (2.1 +/- 1.3 [standard deviation]) had no overlap with normal peripheral zone values and minimal overlap with BPH values (0.61 +/- 0.21). An estimate of the spatial extent of prostate cancer was determined by generating metabolite images in which this metabolite ratio significantly exceeded normal peripheral zone values in multiple contiguous sections. CONCLUSION: These results suggest that a 3D MRSI examination added to a clinical MR imaging examination may help define the presence and spatial extent of prostate cancer.

Adenocarcinoma↗
PubMed1996

Prostate carcinoma: MR imaging findings after cryosurgery.

PURPOSE: To determine the morphologic changes in the prostate gland after cryosurgery and to assess the value of magnetic resonance (MR) imaging in detecting residual tumor. MATERIALS AND METHODS: Twenty-seven patients with prostate carcinoma underwent endorectal MR imaging after cryosurgery. Eighteen patients also underwent MR imaging before cryosurgery. MR findings were correlated with posttreatment clinical data, prostate-specific antigen level, and biopsy results. RESULTS: Mean prostate volume had decreased by 52% in patients examined 8 weeks or more after cryosurgery. Zonal differentiation was lost in 22 of 27 patients (81%). Areas of intraprostatic necrosis were identified in 14 of 27 patients (52%). A thick capsule enveloped the gland and neurovascular bundles in 24 of 27 patients (89%). Osteonecrosis of the symphysis pubis was seen in six of 27 patients (22%). Positive and negative predictive values for MR assessment of recurrent tumor were 44% and 73%, respectively. CONCLUSION: Cryosurgery-induced changes in the prostate gland preclude reliable detection of residual prostate carcinoma at MR imaging.

Aged↗
PubMed1996

Prostate cancer: metabolic response to cryosurgery as detected with 3D H-1 MR spectroscopic imaging.

PURPOSE: To determine, in patients with prostate cancer treated with cryosurgery, whether levels of choline and citrate measured at magnetic resonance (MR) spectroscopy can help discriminate regions of residual tumor from other prostatic tissues and necrosis. MATERIALS AND METHODS: Combined MR imaging and three-dimensional proton spectroscopic imaging were performed in 25 patients (mean age, 69 years) with prostate cancer who underwent cryosurgery. Volume imaging and spectroscopic data were analytically corrected for the reception profile of the endorectal and pelvic phased-array coils. Spectral data were aligned with the MR imaging data and compared with serum prostate-specific antigen levels and biopsy results. RESULTS: Histologically confirmed necrotic tissue (432 voxels) did not demonstrate any observable choline or citrate. The (choline + creatine)/ citrate values in regions of histologically confirmed benign prostatic hyperplasia (0.61 +/- 0.21 [standard deviation], 52 voxels) and cancer (2.4 +/- 1.0, 65 voxels) after cryosurgery were not statistically significantly different from those before therapy but were statistically significantly different from the ratio in necrotic tissue and from each other. The (choline + creatine)/citrate images threshold and overlaid in color on T2-weighted images yielded an estimate of the spatial extent of prostate cancer and benign prostatic hyperplasia. CONCLUSION: Volume MR imaging with MR spectroscopic imaging provided a noninvasive assessment of the presence and location of residual cancer after unsuccessful therapy and helped identify successful cryosurgery in patients who still had an elevated prostate-specific antigen level.

Aged↗
PubMed1996

Local staging of prostatic carcinoma: comparison of transrectal sonography and endorectal MR imaging.

OBJECTIVE: We compared the results of transrectal sonography and endorectal MR imaging in the local staging of prostatic carcinoma. SUBJECTS AND METHODS: 56 patients (mean age, 61.1 +/- 7.3 years) with the diagnosis of prostate cancer who by transrectal sonography had no evidence of gross extracapsular extension underwent endorectal coil MR imaging prior to radical prostatectomy. Imaging findings prospectively evaluated in each patient were cancer laterality, extracapsular extension, and seminal vesicle invasion. Twenty-one of 56 (38%) patients had extracapsular extension on final pathology. A total of 100 sides and five seminal vesicles were involved with cancer, and 27 sides (21 patients, six with bilateral extracapsular extension) demonstrated extracapsular extension. Imaging results were correlated with step-sectioned, radical prostatectomy pathologic data, and statistical analysis was expressed at a p = .05 level of significance. Retrospective readings of the images were used to construct receiver operating characteristic curves for the detection of extracapsular extension. RESULTS: For tumor laterality, transrectal sonography was compared with endorectal coil MR imaging for sensitivity (70% versus 97%; p < .001), specificity (58% versus 58%), positive predictive value (93% versus 95%) and negative predictive value (18% versus 70%). For extracapsular extension, transrectal sonography was compared with endorectal coil MR imaging for the entire prostate and individually for each side of the prostate. The respective results for sensitivity (48% versus 91%, p < .01 and 37% versus 78%, p < .005), specificity (71% versus 49% and 87% versus 73%), positive predictive value (50% versus 51% and 48% versus 48%), and negative predictive value (69% versus 90% and 81% versus 91%). The receiver operating characteristic analysis of retrospective data demonstrated endorectal coil MR imaging to be superior to transrectal sonography in the detection of extracapsular extension. The small number of seminal vesicles involved by cancer (n = 5) precluded meaningful comparisons between the imaging techniques. CONCLUSIONS: Endorectal coil MR imaging is more sensitive but less specific than transrectal sonography for detecting extracapsular extension of carcinoma of the prostate. Both procedures have low positive predictive values yet similarly high negative predictive values when each side of the prostate is assessed independently for extracapsular extension.

Humans↗