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H Hricak

Publications and source records attributed to H Hricak.

At least 55 records · Page 3Linked to original sources
PubMed2000

Magnetic resonance spectroscopic studies of the prostate.

Since the first suggested use of nuclear magnetic resonance (NMR) for detecting cancer, followed by the demonstration of the feasibility of imaging based on the NMR signal in 1973, magnetic resonance imaging (MRI) has become the modality of choice for a variety of clinical applications. Subsequently, the use of NMR spectroscopy (MRS) to detect the presence of different metabolites in vivo has provided unique opportunities for obtaining physiological and biochemical information. More recently, improvements in NMR equipment (magnet, electronics, computers, gradients coils, radiofrequency coils) and pulse sequences (software) have further improved these capabilities. The distinctions between MRI and MRS have begun to blur as new techniques emerge that combine imaging and spectroscopy, generating MRS images of a variety of metabolites. This review provides a brief overview of recent developments in MRS studies pertinent to the clinical evaluation of prostate cancer. The paper has been divided into three parts: a brief qualitative theoretical section about MRS, a review of in vitro studies, and a discussion of the clinical studies of the human prostate.

Adenocarcinoma↗
PubMed1999

Cryptorchidism: strategies in detection.

Imaging evaluation of the patient with a non-palpable testis has evolved over recent decades. The rational explanation of imaging in these patients requires a clear understanding of the various causes of a non-palpable testis, and an appreciation of the utility and limitations of the available imaging modalities. This review describes the classification of non-palpable testis and discusses the role of modern imaging in evaluation. In particular, the relative accuracies of ultrasound, CT and MRI is reviewed.

Angiography↗
PubMed1999

Imaging of peritoneal and mesenteric disease: key concepts for the clinical radiologist.

The abdominal cavity extends from the diaphragm to the pelvic floor, and is lined by a serous membrane known as the peritoneum. The peritoneum is the largest serous membrane in the body, and its surface area is comparable to the surface area of the skin (approximately 2 m2, in adults). Infoldings of the peritoneum suspend the various organs contained in the abdominal cavity. The peritoneum is, therefore, comprised of two layers, a parietal layer lining the abdominal cavity, and a visceral layer enveloping the contained organs. The peritoneal cavity is enclosed between these two layers, and is normally empty, apart from a small amount of physiological fluid. As a result, the normal peritoneal cavity is only a potential space. In men, the space is closed. In women, the fimbriated ends of the Fallopian tubes open into the peritoneal cavity, and provide a potential route of communication with the outside. The peritoneal cavity and the specialized peritoneal infoldings, known as mesenteries, are important disease sites in the abdomen. However, plain radiographs, barium studies, and ultrasound are of limited utility in imaging peritoneal and mesenteric disease. Direct and consistent imaging of such diseases only became possible with the development of computed tomography (CT). Initially, magnetic resonance imaging (MRI) was of limited utility, because of image degradation by motion artifact. With modern fast MRI sequences, it is now possible to depict many of these peritoneal and mesenteric conditions with an accuracy similar to CT. This review will discuss the normal anatomy and physiology of the peritoneal space and mesenteries, and the related disease processes, with particular emphasis on CT and MRI findings. The review is structured along anatomical lines, because many disease processes in the abdomen are site specific, or spread along anatomical pathways. The radiology of peritoneal malignancy and peritoneal adhesions are discussed separately, because these two conditions are not site specific, and because they are conditions whose imaging features are not always well appreciated. Our aim is to present key anatomical and pathological concepts in the imaging of peritoneal and mesenteric disease. We hope this will facilitate a clearer understanding of the CT and MRI appearance of these diseases, and so enhance the ability of the clinical radiologist to formulate rational differential diagnoses, to understand pathways of disease spread, and to apply greater critical analysis in radiological interpretation. The review is not intended as an encyclopaedic description of peritoneal anatomy and pathology.

Adult↗
PubMed1999

Complex posttransplantation abnormalities of renal allografts: evaluation with MR imaging.

PURPOSE: To assess the efficacy of magnetic resonance (MR) imaging in the evaluation of complex abnormalities of renal allografts. MATERIALS AND METHODS: Clinical and radiologic findings were retrospectively reviewed in 24 patients who underwent MR imaging of a renal allograft because ultrasonographic (US) findings were inconclusive or discordant with clinical findings. The final diagnoses were established with histopathologic analysis (n = 16) or clinical and imaging follow-up (n = 8). RESULTS: MR imaging diagnoses were correct in 16 patients (67%), whereas US diagnoses were correct in six patients (25%) (P < .05). Five cases of allograft involvement by posttransplantation lymphoproliferative disorder (PTLD) were found at histopathologic analysis; at MR imaging, PTLD appeared as hypointense masses on T1-and T2-weighted images with minimal enhancement. In four of the five cases of PTLD, the masses occurred at the renal hilum and encased hilar vessels. Normal morphology was correctly diagnosed with MR imaging in five patients in whom a mass was suspected at US. CONCLUSION: MR imaging results are often diagnostic in cases of complex abnormalities of renal allografts. Renal allograft involvement by PTLD appears to have a relatively characteristic MR imaging appearance. Normal MR imaging findings in cases of suspected masses at US may obviate biopsy.

Female↗
PubMed1999

Radiologic staging in patients with endometrial cancer: a meta-analysis.

PURPOSE: To apply a meta-analysis to compare the utility of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging in staging endometrial cancer. MATERIALS AND METHODS: Data were obtained from a MEDLINE literature search and from manual reviews of article bibliographies. Articles were selected that included results in patients with proved endometrial cancer and imaging-histopathologic correlation and that presented data that allowed calculation of contingency tables. Data for the imaging evaluation of myometrial and cervical invasion were abstracted independently by two authors. Data on year of publication, International Federation of Gynecology and Obstetrics (FIGO) stage distribution, and methodologic quality were also collected. A subgroup analysis was performed to compare contrast medium-enhanced MR imaging with nonenhanced MR imaging, US, and CT. RESULTS: Six studies met the inclusion criteria for CT; 16, for US; and 25, for MR imaging. Summary receiver operating characteristic analysis showed no significant differences in the overall performance of CT, US, and MR imaging. In the assessment of myometrial invasion, however, contrast-enhanced MR imaging performed significantly better than did nonenhanced MR imaging or US (P < .002) and demonstrated a trend toward better results, as compared with CT. The lack of data on the assessment of cervical invasion at CT or US prevented meta-analytic comparison with data obtained at MR imaging. Results were not influenced by year of publication, FIGO stage distribution, or methodologic quality. CONCLUSION: Although US, CT, or MR imaging can be used in the pretreatment evaluation of endometrial cancer, contrast-enhanced MR imaging offers "one-stop" examination with the highest efficacy.

Endometrial Neoplasms↗
PubMed1999

Prostate cancer: localization with three-dimensional proton MR spectroscopic imaging--clinicopathologic study.

PURPOSE: To assess the efficacy of combined magnetic resonance (MR) imaging and three-dimensional (3D) proton MR spectroscopic imaging in the detection and localization of prostate cancer. MATERIALS AND METHODS: MR imaging and 3D MR spectroscopic imaging examinations were performed in 53 patients with biopsy-proved prostate cancer and subsequent radical prostatectomy with step-section histopathologic examination. The prostate was divided into sextants. At MR imaging, the presence or absence of cancer in the peripheral zone of each sextant was assessed independently by two readers (readers 1 and 2) unaware of the findings at 3D MR spectroscopic imaging and histopathologic examination. At 3D MR spectroscopic imaging, cancer was diagnosed as possible if the ratio of choline plus creatine to citrate exceeded 2 SD above population norms or as definite if that ratio exceeded 3 SDs above the norm. RESULTS: On the basis of sextants, sensitivity and specificity, respectively, for MR imaging were 77% and 61% (reader 1) and 81% and 46% (reader 2) with moderate interreader agreement (kappa = 0.43). The 3D MR spectroscopic imaging diagnosis of definite cancer had significantly higher specificity (75%, P < .05) but lower sensitivity (63%, P < .05). Receiver operating characteristic analysis showed significantly (P < .001) improved tumor localization for both readers when 3D MR spectroscopic imaging was added to MR imaging. High specificity (up to 91%) was obtained when combined MR imaging and 3D MR spectroscopic imaging indicated cancer, whereas high sensitivity (up to 95%) was obtained when either test alone indicated a positive result. CONCLUSION: The addition of 3D MR spectroscopic imaging to MR imaging provides better detection and localization of prostate cancer in a sextant of the prostate than does use of MR imaging alone.

Cross-Sectional Studies↗
PubMed1999

Prostate cancer: prediction of extracapsular extension with endorectal MR imaging and three-dimensional proton MR spectroscopic imaging.

PURPOSE: To determine if the addition of three-dimensional (3D) proton magnetic resonance (MR) spectroscopic imaging to endorectal MR imaging helps diagnose extracapsular extension (ECE) of prostate cancer. MATERIALS AND METHODS: Endorectal MR imaging and 3D MR spectroscopic imaging were performed in 53 patients with prostate cancer before radical prostatectomy. MR imaging studies were evaluated by two independent readers unaware of histopathologic findings. The presence of ECE was graded on a five-point scale. At 3D MR spectroscopic imaging, cancer was diagnosed if the ratio of choline plus creatine to citrate was 2 or more SDs above normal. The accuracy of MR imaging alone was compared with that of combined MR imaging and 3D MR spectroscopic imaging, with use of the step-section histopathologic results as the standard of reference. RESULTS: For the less experienced reader, the addition of 3D MR spectroscopic imaging to MR imaging significantly improved accuracy (area under the receiver operating characteristic curve [Az] = 0.75 vs Az = 0.62, P < .05). For the more experienced reader, the addition improved accuracy but not significantly (Az = 0.86 vs Az = 0.78). The addition also reduced interobserver variability (Az = 0.86 vs Az = 0.75). CONCLUSION: The addition of 3D MR spectroscopic imaging to MR imaging improves accuracy for less experienced readers and reduces interobserver variability in the diagnosis of ECE of prostate cancer.

Cross-Sectional Studies↗
PubMed1999

Complex fetal disorders: effect of MR imaging on management--preliminary clinical experience.

PURPOSE: To determine the effect of magnetic resonance (MR) imaging findings on management of complex fetal disorders. MATERIALS AND METHODS: MR imaging of the fetus was performed in 25 consecutive pregnant patients referred because of possible complex fetal disorders suspected on the basis of ultrasonographic (US) findings. Spoiled gradient-echo and single-shot rapid acquisition with relaxation enhancement MR imaging were performed in multiple planes anatomic to the fetus during maternal breath holding. RESULTS: In the fetuses in 24 of 25 women, MR studies were technically satisfactory. MR imaging directly influenced fetal care in four (17%) of 24 cases by demonstrating congenital high airway obstruction syndrome, congenital hemochromatosis, unilateral cerebellar deficiency in association with congenital diaphragmatic hernia, and severe facial disfigurement due to a giant anterior neck mass. In eight (33%) cases, MR imaging provided supplementary findings, but did not affect fetal care. In 12 (50%) cases, MR imaging results confirmed US findings. CONCLUSION: In cases of complex fetal disorders, MR imaging results can be used to supplement or confirm US findings and may directly affect management.

Abnormalities, Multiple↗
PubMed1999

Diffuse retroperitoneal amyloidosis due to renal cell carcinoma.

The case of a 61-year-old man with haematuria, in whom CT demonstrated a solid renal mass and extensive retroperitoneal infiltration, is presented. This combination of CT findings resulted in significant diagnostic uncertainty. Pathological analysis demonstrated renal cell carcinoma, with secondary amyloidosis in the retroperitoneum. Amyloidosis secondary to renal cell carcinoma has not been previously described as a cause of retroperitoneal infiltration.

Amyloidosis↗
PubMed1998

Inconclusive clinical and ultrasound evaluation of the scrotum: impact of magnetic resonance imaging on patient management and cost.

OBJECTIVES: To determine the diagnostic utility and net cost of magnetic resonance imaging (MRI) in the management of clinically and sonographically inconclusive scrotal lesions. METHODS: A multicenter retrospective review identified 34 patients diagnosed with scrotal MRI following inconclusive clinical and ultrasound (US) evaluation. Final diagnoses were based on surgery (n = 18) or clinical and US follow-up (n = 16). Final diagnoses of 29 testicular lesions were as follows: orchitis (n = 11), infarct (n = 6), neoplasm (n = 6), rupture (n = 3), torsion (n = 2), and radiation fibrosis (n = 1). Final diagnoses of five extratesticular lesions were as follows: epididymitis (n = 2), epididymal abscess (n = 2), and neoplasm (n = 1). Management plans prior to and following MRI findings were formulated by a general urologist and a urologic oncologist. The costs of the pre-MRI and post-MRI management plans were estimated using the Medicare reimbursement schedule. RESULTS: The leading US diagnosis was correct for 10 of 34 patients (29%) and the leading MRI diagnosis was correct for 31 of 34 patients (91%). MRI improved the management plan of the general urologist and urologic oncologist in 19 patients (56%) and 17 patients (50%), respectively. MRI worsened the management plan of both clinicians in 1 patient. Management was unchanged in all other patients. The overall net cost savings were $543 to $730 per patient for the urologic oncologist and the general urologist, respectively, and $3833 per patient originally scheduled for surgery. CONCLUSIONS: Use of MRI after inconclusive clinical and US evaluation of scrotal lesions may improve management, decrease the number of surgical procedures, and result in net cost savings.

Adolescent↗
PubMed1998

Imaging and management of atypical testicular masses.

Most testicular masses are germ cell malignancies and require radical orchiectomy. There are other causes of testicular masses, however, some of which have characteristic imaging and clinical features. A presumptive diagnosis may be possible for some of these atypical testicular masses. This may result in testis-preserving surgery or nonoperative management.

Diagnosis, Differential↗
PubMed1998

Localizing prostate cancer in the presence of postbiopsy changes on MR images: role of proton MR spectroscopic imaging.

PURPOSE: To assess whether magnetic resonance (MR) spectroscopic imaging with MR imaging can improve prostate cancer localization in postbiopsy hemorrhage cases. MATERIALS AND METHODS: Records of 175 patients with prostate cancer were retrospectively reviewed; 42 patients (135 hemorrhagic sites) had spatially correlated biopsy data. Patients underwent both phased-array coil-endorectal coil MR imaging and three-dimensional MR spectroscopic imaging within 180 days after transrectal ultrasound (US)-guided biopsy. High-signal-intensity hemorrhage on T1-weighted images and corresponding high- or low-signal-intensity areas on T2-weighted images and the metabolic ratio (choline + creatine)/citrate were recorded. Cancer was identified as a low-signal-intensity area at T2-weighted MR imaging or a metabolite ratio greater than 3 standard deviations above normal at MR spectroscopic imaging. MR imaging, spectroscopic, and biopsy findings were compared. RESULTS: Forty-nine patients had postbiopsy hemorrhage. On T2-weighted images, a higher (P < .01) percentage of hemorrhagic sites demonstrated low signal intensity (80% [108 of 135 sites]), which is similar to the signal intensity seen with cancer. The addition of MR spectroscopic imaging to MR imaging resulted in a significant increase (P < .01) in the accuracy (52% to 75%) and specificity (26% to 66%) of tumor detection. CONCLUSION: The addition of MR spectroscopic imaging to MR imaging significantly improves the ability to determine the presence of prostate cancer and spatial extent when postbiopsy changes hinder interpretation with MR imaging alone.

Aged↗