Prostate cancer: gadolinium-enhanced MR imaging at 3 weeks compared with needle biopsy at 6 months after cryoablation.

PURPOSE: To determine if nonenhancing tissue on gadolinium-enhanced magnetic resonance (MR) images obtained 3 weeks after cryoablation of the prostate helps reliably and accurately predict nonviable cryoablated tissue at 6-month biopsy. MATERIALS AND METHODS: Fifty-four consecutive patients with prostate cancer who underwent cryoablation were followed up prospectively. Fifty-one underwent gadolinium-enhanced MR imaging at 3 weeks (three had gadolinium allergy); 49, biopsy at 6 months (three refused and two had other primary malignancies); and all, prostate-specific antigen (PSA) tests at 6 weeks, 3 months, and every 3 months thereafter. MR images were evaluated and scored according to the degree of signal void and were correlated with the 6-month biopsy reports and, to a lesser degree, PSA levels. The biopsy reports were examined for the presence or absence of cancerous tissue, viable tissue, and nonviable tissue. A one-way analysis of variance was used for statistical and regression analyses. RESULTS: The correlation of MR imaging scores with PSA levels and MR imaging scores with biopsy findings resulted in P values of.337 and.780, respectively. A slight statistically significant trend existed for the relation of biopsy results with PSA levels, with a P value of.041, which was expected. CONCLUSION: Findings of postoperative gadolinium-enhanced MR imaging are not predictive of 6-month biopsy results or follow-up PSA levels.

A prospective, double-blind comparison of magnetic resonance imaging and arthroscopy in the evaluation of patients presenting with shoulder pain.

The purpose of this study was to determine the diagnostic ability of magnetic resonance imaging (MRI) compared with a reference standard, arthroscopy, in patients presenting with shoulder pain consistent with the signs and symptoms of shoulder impingement. Fifty-eight patients in whom conservative management failed underwent standardized MRI with intravenous gadolinium enhancement and arthroscopic evaluation. The prevalence of supraspinatus tendon, long head of the biceps tendon, and acromioclavicular joint pathology in this population was high: 79.3%, 66%, and 56%, respectively. MRI was highly accurate in detecting full-thickness supraspinatus tears and acromioclavicular joint pathology. However, it had poor concordance with arthroscopy in diagnosing pathology in the biceps tendon and in classifying the curvature of the acromion. A smaller number of other abnormal structures were identified in this population of patients, including labral abnormalities (superior labral anterior-posterior and Bankart tears), Hill-Sachs lesions, and articular surface damage. Concordance between MRI and arthroscopy would increase with improved radiologist-surgeon communication, a more reliable classification of pathology, and possibly the use of intraarticular contrast. This study demonstrates that patients presenting with the clinical findings of shoulder impingement syndrome represent a heterogeneous population. Overall, MRI is a useful tool in the identification of shoulder pathology; however, the clinical correlation of this information and the assessment of outcomes remains unknown.

Use of a heterologous monoclonal antibody for cloning and detection of glial fibrillary acidic protein in the bovine ventricular ependyma.

From protozoans to vertebrates, ciliated cells are characterized by well-developed cytoskeletal structures. An outstanding example is the epiplasm, a thick, submembranous skeleton that serves to anchor basal bodies and other cell surface-related organelles in ciliated protozoans. An epiplasm-like cytoskeleton has not yet been observed in metazoan ciliated cells. In a previous study, we reported on MAb E501, a monoclonal antibody raised against epiplasmin-C, the major membrane skeletal protein in the ciliate Tetrahymena pyriformis. It was shown that MAb E501 cross-reacts with glial fibrillary acidic protein (GFAP), the class III intermediate filament protein found in astrocytes and other related glial elements. Here we used a post-embedding immunogold-staining method to localize MAb E501 cross-reactive antigens in ciliated cells from the ventricular ependyma in bovine embryos. When ependymocytes were treated with MAb E501, the ciliated region of the cell cortex was devoid of significant labeling. Instead, a gold particle deposit was evident around the nucleus, with only conventional ependymocytes being immunostained. Similar results were obtained by utilizing a rabbit antiserum against GFAP, revealing glial filaments and indicating an astroglial lineage of conventional bovine ependymocytes. In contrast, secretory ependymocytes of the subcommissural organ (SCO) were not stained by either of the two antibodies. Using MAb E501 as a heterologous probe, we cloned bovine GFAP cDNA. In situ hybridization experiments failed to detect GFAP transcripts in SCO ependymocytes, confirming the abscence of immunoreactivity in these cells.

Gadolinium-enhanced dynamic MRI of the fractured carpal scaphoid: preliminary results.

The aim of the present report was to evaluate the vascularity of fracture fragments of the fractured carpal scaphoid in the acute (< 4 weeks) and chronic (> 3 months) phases using a gadolinium-enhanced dynamic MRI sequence. Eight patients with acute scaphoid fractures, six patients with chronic scaphoid fractures, and three control patients without fractures were evaluated using a T1-weighted fast spoiled gradient recalled acquisition (fSPGR) sequence with gadolinium-DTPA enhancement (0.1 mmol/kg bodyweight). Signal intensity over time plots were obtained using region of interest measurements from both fracture fragments. Enhancement factors (EF) were then calculated from the plots. No enhancement of the scaphoid was seen in control subjects (EF: distal scaphoid pole 1.04 +/- 0.01, proximal pole 1.07 +/- 0.08). In acute fracture patients, enhancement of the distal pole was greater than that of the proximal in all cases but one in which the two poles enhanced in a similar fashion (EF: distal 1.99 +/- 0.77, proximal 1.43 +/- 0.99). In chronic fracture patients the enhancement pattern was reversed, as the proximal pole enhanced to a greater degree than the distal with the exception of one case where both poles enhanced equally (EF: distal 1.74 +/- 0.52, proximal 2.64 +/- 0.50). Using a two-tailed non-parametric Mann-Whitney U-test, the difference in enhancement of the proximal poles between the acute and chronic groups was found to be highly significant (P < 0.003). Dynamic contrast-enhanced (fSPGR) MRI demonstrates significant differences in the enhancement patterns of the scaphoid when chronic and acute fractures are compared.

Diagnostic equivalence of conventional and fast spin echo magnetic resonance imaging of the anterior cruciate ligament of the knee.

Many techniques and pulse sequences have been devised for the assessment of the anterior cruclate ligament. The present study compares fast spin echo (FSE) imaging to conventional spin echo imaging at a field strength of 1.5 T in an effort to determine if these sequences are diagnostically equivalent. Where available, arthroscopy was also done. A total of 52 patients were imaged using both FSE and conventional spin echo sequences. Eight volunteers were used as controls. Arthroscopy was performed on 10 patients. The anterior cruciate ligament was assessed in a blinded fashion by three radiologists. The Kappa statistic was then used to determine the percentage agreement between FSE and conventional spin echo imaging. Fast spin echo sequencing demonstrated a sensitivity of 100%, a specificity of 94.8% and an accuracy of 96.3% when compared to arthroscopy. Conventional spin echo imaging and arthroscopy had a sensitivity of 100%, specificity of 84.6% and an accuracy of 88.9%. The remaining 34 patients who did not undergo arthroscopy were followed clinically because clinical and imaging findings were not suggestive of ACL tears. These demonstrated 72% agreement between FSE and conventional spin echo imaging using the Kappa statistic, with regards to calling ACL normal or having only a low-grade partial tear. Fast spin echo imaging produces images of the anterior cruciate ligament that have similar diagnostic accuracy to conventional spin echo images (P < 0.05) within a much shorter scan time. These results however, require further validation in a larger group, preferably with arthroscopic correlation.

Prostatic cryosurgery: use of MR imaging in evaluation of success and technical modifications.

PURPOSE: To evaluate the usefulness of contrast material-enhanced magnetic resonance (MR) imaging in objective assessment of prostatic cryosurgery and the role of MR imaging in the modification of prostatic cryosurgical technique. MATERIALS AND METHODS: Thirty-eight consecutive patients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enhancement before cryosurgery and unenhanced and gadolinium-enhanced MR imaging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging findings were correlated with those from transrectal ultrasound-directed prostatic staging biopsy. RESULTS: Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-enhanced images. With progressive modification of cryosurgical technique, complete cryoablation of the prostate was achieved in the latter nine of the 38 patients. When cryoablation was considered complete according to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor. CONCLUSION: Gadolinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging findings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.

The frequency of venous thrombosis in cemented and non-cemented hip arthroplasty.

We randomised 250 patients undergoing unilateral, elective hip arthroplasty for osteoarthritis to receive either a cemented or a non-cemented Mallory Head prosthesis. Aspirin was used as prophylaxis against thromboembolism during the first half of the study and adjusted-dose warfarin during the second half. Postoperatively, all patients were asked to have bilateral venography and 80% agreed. All were evaluated clinically for pulmonary embolism. There was no difference in the frequency of deep-venous thrombosis between the two groups (50% cemented nu 47% non-cemented, p = 0.73; 95% CI of the difference -13.6% to 19.3%). Three of the 64 patients (5%) in whom venography had demonstrated isolated distal thrombi developed pulmonary emboli.

Anterior cruciate ligament tear: prospective evaluation of diagnostic accuracy of middle- and high-field-strength MR imaging at 1.5 and 0.5 T.

PURPOSE: To compare the diagnostic efficacy of current-generation middle- and high-field-strength magnetic resonance (MR) imagers in the diagnosis of anterior cruciate ligament (ACL) tears. MATERIALS AND METHODS: In 114 of 230 patients referred for knee imaging, MR imaging at 0.5 and 1.5 T was performed with identical sequences but with a slightly longer total imaging time and bandwidth optimization at 0.5 T. Radiologists were blinded to diagnosis and field strength. Sensitivity, specificity, and accuracy were determined, and ACL tear was confirmed by means of arthroscopy and pathology. RESULTS: There was no difference between the field strengths in accuracy, sensitivity, or specificity for the diagnosis of ACL tears in 86 patients with disrupted ACLs and 28 patients with intact ACLs. Accuracy for all ACL tears was 90% at 0.5 T and 91% at 1.5 T. Similarly, there were no differences in diagnosis of meniscal tears (79 with, 149 without) or posterior cruciate ligament tears (seven with, 107 without). CONCLUSION: Higher field strength does not confer higher accuracy in the diagnosis of ACL tears at MR imaging.

Patellar tendinitis: MR imaging features, with suggested pathogenesis and proposed classification.

PURPOSE: To characterize the magnetic resonance (MR) imaging features of patellar tendinitis. MATERIALS AND METHODS: Fifteen patients with a clinical diagnosis of patellar tendinitis underwent gadolinium-enhanced MR imaging of the knee. RESULTS: Grades of patellar abnormality, based on findings in the enthesial region at MR imaging, correlated with signs of increasing fibrovascular repair: grade 1 (n = 4), enhancing area adjacent to patellar apex, with marginal zone of intermediate signal intensity, and a patellar apical chondral-bone avulsion; grade 2 (n = 5), same signs as grade 1 damage but without avulsion; grade 3 (n = 6), homogeneous, nonenhancing area of intermediate signal intensity adjacent to the patellar apex seen on all images. Changes were most obvious posteriorly and involved the central and medial thirds of the tendon. Chronic injury to the medial retinaculum was a common associated finding. CONCLUSION: Patellar tendinitis demonstrates a consistent spectrum of changes at MR imaging that can aid understanding of the origin and treatment of damage.

Magnetic resonance imaging evaluation of the rotator cuff tendons in the asymptomatic shoulder.

Thirty shoulders in 20 volunteers (average age, 29 years; range, 17 to 49) with no shoulder symptoms or known abnormalities were scanned using magnetic resonance imaging. All scans were interpreted by one radiologist who was blinded to clinical data. Appearance of rotator cuff tendons on the images was graded. Grade 0 was normal, homogeneous low signal intensity structure. Grade 1 lesion was focal, linear, or diffuse intermediate signal through the tendon. Grade 2 lesion was high signal intensity within the tendon and less than full thickness. Grade 3 was high signal intensity through full thickness of the tendon. No supraspinatus or infraspinatus tendons were grade 0 (normal); all supraspinatus and infraspinatus tendons had grade 1 changes through the tendons; and 7 of 30 (23%) of the tendons had grade 2 changes. None of the 30 shoulders had grade 3 changes in the rotator cuff tendons. There is a wide array of abnormal magnetic resonance imaging signals in shoulders of young asymptomatic individuals, but they do not have full-thickness rotator cuff tears (grade 3 lesion). Nonenhanced magnetic resonance imaging may be of limited value in defining rotator cuff injury in a patient with shoulder pain unless a full-thickness rotator cuff tear is suspected clinically.

MR imaging field strength: prospective evaluation of the diagnostic accuracy of MR for diagnosis of multiple sclerosis at 0.5 and 1.5 T.

PURPOSE: To compare the diagnostic efficacy of middle-field-strength and high-field-strength magnetic resonance (MR) imaging in diagnosis of multiple sclerosis. MATERIALS AND METHODS: One hundred thirty-two patients with suspected multiple sclerosis underwent MR imaging at 0.5 and 1.5 T. Imaging parameters were identical except for band width optimization at middle field strength. Images were interpreted by radiologists expert in MR imaging who were blinded to diagnosis and field strength. The diagnosis of multiple sclerosis was made by experienced neurologists, and indeterminate cases and patients without clinical evidence of multiple sclerosis were followed up for 6 months to 1 year. RESULTS: There was no difference in accuracy, sensitivity, or specificity between scanners in the diagnosis of multiple sclerosis or white matter disease. Equal numbers of lesions were detected at both field strengths in all parts of the brain. Image quality was always good or adequate at middle field strength. CONCLUSION: Higher field strength does not confer higher accuracy in the diagnosis of multiple sclerosis with current-generation MR imagers.

Musculoskeletal infection: findings on magnetic resonance imaging.

Magnetic resonance imaging (MRI) can provide considerable useful information in cases of musculoskeletal infection, in particular demonstrating the extent of involvement of soft tissues and medullary bone. Differentiation between infected tissue and abscess is also possible with MRI, especially if contrast agent is administered. MRI therefore serves as an adjunct to other imaging modalities, especially in complex cases. This review covers various manifestations of musculoskeletal infection as depicted with MRI.

The emerging role of magnetic resonance imaging in rheumatology.

The role of magnetic resonance imaging (MRI) in imaging the central nervous system and in orthopedic radiology is now well accepted. Numerous applications of this technique also exist in the field of rheumatology, and it is anticipated that MRI will play an important part in the evaluation of treatments for the arthritides. In addition, MRI allows noninvasive investigation of other rheumatologic problems, such as avascular necrosis, tendon disorders and myopathy. This review outlines the current applications of MRI in rheumatologic practice.

Adamantinoma of the tibia: plain-film, computed tomography and magnetic resonance imaging appearance.

The authors describe the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of adamantinoma of the tibia in a 29-year-old man. Adamantinoma is a rare, aggressive osteolytic lesion occurring primarily in the diaphyseal portion of long bones. Because of its rarity the MRI features have been infrequently reported. In this case MRI provided more accurate information about the extent and invasiveness of the tumour than either plain radiography or CT.

Imaging after arthroplasty.

Arthroplasty is now an important and frequently performed orthopedic procedure. This article focuses on the imaging of abnormalities frequently encountered in patients who have undergone arthroplasty. The emphasis is on plain film analysis, although arthrography, computed tomography and nuclear medicine are also discussed. Among the problems illustrated are loosening of the prosthesis, component fatigue or failure, and infection. The authors recommend techniques to optimize imaging. Although most of the entities illustrated involve hip arthroplasty, the principles are valid for arthroplasty at other sites.

Self-contained, inflatable penile prosthesis: magnetic resonance appearance.

The appearance of an inflatable penile prosthesis, visualized on a short tau inversion recovery sequence, is reported, in a patient who had magnetic resonance imaging for pelvic pain subsequent to radical cystoprostatectomy for bladder carcinoma. With suppression of adjacent fat signal, the prosthesis is well delineated from adjacent structures. The fluid-containing cylinders of the prosthesis are of very bright signal intensity, with the relief valve assembly of low signal intensity.

Magnetic resonance imaging of a giant nonfunctioning retroperitoneal paraganglioma.

The authors describe the magnetic resonance imaging (MRI), computed tomographic, ultrasonographic and angiographic appearance of a giant nonfunctioning retroperitoneal paraganglioma. To their knowledge, the MRI appearance of a nonfunctioning paraganglioma has not been previously described. The MRI characteristics of the nonfunctioning tumour were similar to those of a functioning paraganglioma and included hyperintensity in T2-weighted images and intense enhancement after intravenous administration of contrast agent.