MR imaging of silicone breast implants: evaluation of prospective and retrospective interpretations and interobserver agreement.

MR imaging was used to evaluate the integrity of silicone breast implants in 54 women with 108 implants. MR images were interpreted by relatively inexperienced readers who tried to reproduce the experiences reported in the literature. The study examines the interobserver agreement using different diagnostic signs and the influence of experience on interpretation errors. Prospective and retrospective interpretations were compared with surgical findings at the time of explanation. Diagnostic indicators, including the linguine sign, the inverted tear drop sign, the C sign, water droplets mixed with silicone, and extracapsular globules of silicone, were evaluated for diagnostic efficacy and interobserver agreement. The prospective sensitivity and specificity were 87% and 78%, respectively. With the retrospective interpretations, the sensitivity and specificity increased to 93% and 92%, respectively. Most of the prospective false-positive interpretations were due to misinterpreting radial folds as signs of implant rupture. Six implants interpreted retrospectively as false positives had gross amounts of silicone around the implants at surgery but there were no obvious rents in the implant shells. There was fair to excellent interobserver agreement with the individual diagnostic signs except for extracapsular globules of silicone. All of the signs had specificities of greater than 90%. The sensitivities of the individual signs were less than the overall retrospective sensitivity. With experience, the sensitivity improved from 87% to 93% and the specificity improved from 78% to 92%. This study helps substantiate the use of diagnostic signs used by other authors to detect silicone loss from breast implants by MR imaging; however, questions remain as to the clinical role of MR imaging in evaluating implants for silicone loss.

Coronal fat suppression fast spin echo images of the knee: evaluation of 202 patients with arthroscopic correlation.

We optimized fat-suppressed fast spin echo (FS-FSE) parameters for coronal imaging of the knee and then evaluated the technique in a clinical setting. Five volunteers and 12 patients were used to evaluate various repetition (TR), echo (TE), and echo train lengths (ETL). Then, 202 patients underwent both knee MR imaging using coronal plane FS-FSE and arthroscopy. The coronal FS-FSE images were compared with radial multiplanar gradient-recalled echo (MPGRE), axial T1-weighted SE, and parasagittal double echo SE images. Proton density images (2,000/19) with an ETL of 2 best depicted the menisci, ligaments, and capsules. The conspicuity of osteochondral abnormalities depicted by the coronal FS-FSE imaging was significantly higher than for axial T1-weighted SE (p < .003) and parasagittal echo SE images (p < .003). The accuracy of the coronal FS-FSE imaging for medial and lateral meniscal tears was 91.6% and 87.6%, respectively. Combined imaging interpretation of the coronal FS-FSE, axial T1-weighted SE, and radial MPGRE imaging improved the accuracy for meniscal tears slightly over any sequence used alone, but the difference was not statistically significant. Fourteen capsular injuries were demonstrated by the coronal FS-FSE imaging. FS-FSE imaging in the coronal plane is a useful complementary sequence in MR examinations of the knee for the evaluation of meniscal tears, capsular injuries, and osteochondral abnormalities.

Percutaneous transluminal angioplasty versus endovascular stent placement in the treatment of venous stenoses in patients undergoing hemodialysis: intermediate results.

PURPOSE: This report describes intermediate findings from an ongoing prospective randomized trial comparing the results of percutaneous transluminal angioplasty (PTA) with results of endovascular stent placement in patients undergoing hemodialysis. PATIENTS AND METHODS: Among 87 consecutive patients with venous stenoses or occlusions, 47 (54%) were treated with PTA alone and 40 (46%) were treated with PTA and stent placement. RESULTS: For peripheral sites, the primary patency rates for PTA at 60, 180, and 360 days were 55%, 31%, and 10%, respectively, and for stents were 36%, 27%, and 11%, respectively (P = .6528). The secondary patency rates for PTA at 60, 180, and 360 days were 94%, 80%, and 71%, respectively, and for stents were 73%, 64%, and 64%, respectively (P = .1677). For central sites, the primary patency rates for PTA at 60, 180, and 360 days were 81%, 23%, and 12%, respectively, and for stents were 67%, 11%, and 11%, respectively (P = .4595). The secondary patency rates for PTA were 100% at each interval, and for stents were 100%, 89%, and 78%, respectively (P = .5408). CONCLUSION: Intermediate results suggest that, overall, there is no difference in the patency rates for peripheral venous stenoses in dialysis patients treated with PTA or PTA and endovascular stent placement. At this time, the numbers of patients are too small to conclude if certain sites such as larger central veins will respond better to one treatment or the other.

The role of percutaneous needle biopsies in the original diagnosis of lymphoma: a prospective evaluation.

PURPOSE: A prospective evaluation to determine if percutaneous needle biopsy yields enough tissue to establish the diagnosis of lymphoma and initiate therapy. PATIENTS AND METHODS: Lymphoma was diagnosed in 43 patients for the first time. Patients underwent either a core needle biopsy (n = 41) or an aspiration-type needle biopsy (n = 2) performed with imaging guidance. Immunochemical studies were performed on specimens from 39 of 43 patients (91%); flow cytometry was performed formed on specimens from 10 patients (23%). Patient progress was followed to see if biopsy results were used as a basis for treatment or if additional material was obtained with an open surgical procedure. RESULTS: On the basis of treatment decisions, needle biopsy results were sufficient for a diagnosis to be made in 36 of 43 patients (84%). In seven patients (16%), needle biopsy specimens were considered nondiagnostic, suspicious for lymphoma, or insufficient. None of the 43 patients responded to therapy in a manner that suggested the diagnosis of lymphoma to be incorrect. CONCLUSION: Image-guided needle biopsy should be the first procedure performed in the diagnosis of lymphoma, except in easily accessible superficial neck, inguinal, and axillary nodal sites.

Rotator cuff tendon tears: evaluation with fat-suppressed MR imaging with arthroscopic correlation in 100 patients.

PURPOSE: To evaluate the diagnostic accuracy of fat-suppressed magnetic resonance (MR) imaging of rotator cuff tears in a large symptomatic population. MATERIALS AND METHODS: One hundred patients underwent both MR imaging and arthroscopy of the shoulder. Ninety-two patients underwent fat-suppressed conventional spin-echo MR imaging (repetition time msec/echo time msec = 2,500/20, 60), and eight patients underwent fat-suppressed, fast spin-echo MR imaging (2,000/80). RESULTS: With data combined for complete and partial tears of the rotator cuff (n = 31), MR imaging had an accuracy of 93%; sensitivity, 84%; and specificity, 97%. Seventeen of 20 complete tears and nine of 11 partial tears were properly identified with MR imaging. Two partial tears were not detected and three complete tears were incorrectly called partial tears at MR imaging. Of two false-positive MR imaging findings, one was called a complete tear and the other, a partial tear. CONCLUSION: Fat-suppressed MR imaging has high diagnostic accuracy in evaluating tears of the rotator cuff tendon.

Chondromalacia patellae: fat-suppressed MR imaging.

PURPOSE: To evaluate the accuracy of fat-suppressed magnetic resonance (MR) imaging in diagnosing chondromalacia patellae. MATERIALS AND METHODS: Seventy-one patients underwent fat-suppressed MR imaging and arthroscopy of the patellofemoral compartment. Findings were classified as early or advanced chondromalacia or as normal and were correlated with arthroscopic findings. RESULTS: Early and advanced stages of chondromalacia patellae were reliably detected, with positive predictive values of 85% and 92%, respectively. Specificity in early stages was 94% and in late stages was 98%. However, the overall accuracies did not differ substantially from those reported in studies that did not use fat-suppressed imaging. CONCLUSION: Axial, fat-suppressed MR imaging accurately depicts changes caused by chondromalacia patellae. Early stages can be seen as intrasubstance changes of increased signal intensity. Results of this study suggest a high degree of specificity in excluding both early and advanced changes.

MR imaging of the patellofemoral compartment.

This article reviews the applications of MR imaging of the patellofemoral compartment. Axial plane images are the most informative for abnormalities of this compartment. The role of MR imaging in the evaluation of the medial synovial plica and in the detection of chondromalacia is discussed. MR imaging can reliably detect and delineate the complex of injuries associated with patellar dislocations and valgus hyperextension.

Thyroid biopsies: fine-needle aspiration biopsy versus spring-activated core biopsy needle in 102 patients.

PURPOSE: Use of the single-action spring-activated core biopsy needle was compared with the fine needle aspiration biopsy (FNAB) technique in ultrasound (US)-guided thyroid biopsies. PATIENTS AND METHODS: Results in 102 patients who underwent sonographically guided thyroid biopsies with both fine needles and core biopsy needles were prospectively evaluated. Results from the 21-gauge FNAB (n = 102) were compared with results from 18-gauge (n = 1), 19-gauge (n = 2), 20-gauge (n = 43), or 21-gauge (n = 56) single-action spring-activated core biopsy needles. RESULTS: If the suggestive and diagnostic results were combined, the diagnostic accuracy for the core biopsy needle was 90.2% (92 of 102) and was 80.3% (82 of 102) for FNAB (P = .048). The diagnostic accuracy for the combination of both needles was 97.1% (99 of 102). The complication rate was 0.98% (n = 1). This complication was a minor soft-tissue infection successfully treated with orally administered antibiotics. CONCLUSION: In summary, sonographically guided biopsies of the thyroid performed with single-action core biopsy needles are safe and effective. The results with use of these needles are better than the results of FNAB, but the best results are obtained when both needles are used in the same patient.

MR imaging of prostate cancer with an endorectal surface coil technique: correlation with whole-mount specimens.

PURPOSE: To evaluate the diagnostic accuracy of magnetic resonance (MR) imaging in staging prostate cancer with an endorectal surface coil technique. MATERIALS AND METHODS: The authors prospectively evaluated MR images obtained with an endorectal surface coil from 70 consecutive patients with known prostate cancer. Gadopentetate dimeglumine was administered to 40 patients. Multiple sequences were used, including conventional and fast spin echo, with and without fat suppression. The readers were blinded to the MR findings unless bone or nodal metastasis was present. MR images were compared with whole-mount sections. RESULTS: The prospective staging accuracy for MR imaging was 51% (36 of 70 patients). Stage B disease was present in 27 patients (38%), stage C in 42 (60%), and stage D in one (1%). The retrospective staging accuracy was 67% (47 of 70 patients). Of the 42 patients with stage C disease, positive surgical margins were present in 36 (85%). Gadopentetate dimeglumine did not help detect or stage tumors. CONCLUSION: Further studies must be performed to determine the role of endorectal coil MR imaging in the staging of prostate cancer.

Large-caliber (24-28-F) catheters for radiologically guided percutaneous procedures.

A catheter set originally designed as a system for placement of large thoracostomy tubes with the Seldinger technique and sequential coaxial dilations was used to place 31 catheters in 28 patients. Either computed tomographic (CT) (n = 25) or fluoroscopic (n = 3) guidance was used. The tubes were 28 F (n = 13) and 24 F (n = 18). The tubes were successfully placed in 27 of 28 patients (96%), with the infection processes completely resolved in 22 of 25 patients (88%). Use of the system is simple and safe. These large catheters may be useful for cure of processes that do not respond to drainage with smaller tubes.

MR imaging of patellar retinacular ligament injuries.

Seventeen patients with patellar retinacular ligament injuries were evaluated with magnetic resonance (MR) imaging. MR findings were correlated with clinical, surgical, and arthroscopic findings. The injuries involved the medial retinacular ligament in 16 of 17 patients and the medial and lateral retinacular ligament in one patient. Nine of 17 patients showed MR evidence of a patellar dislocation. In these patients, a triad of findings that included focal impaction injuries involving the lateral femoral condyle, osteochondral injuries of the medial patellar facet, and injuries of the medial retinacular ligament were seen. Seven of the nine patients with patellar dislocation injuries had frank osteochondral injuries. The injured retinaculum had an indistinct, irregular appearance associated with edema and hemorrhage. The patellar dislocations were clinically unsuspected in the initial evaluation of eight of these nine patients. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). In the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. MR imaging can help define patellar retinacular and associated osteochondral injuries, which may be clinically useful information.

Femoral MR angiography versus conventional angiography: preliminary results.

PURPOSE: To develop a bilateral femoral magnetic resonance (MR) angiographic examination that would include the aortic bifurcation to the ankle. MATERIALS AND METHODS: Thirty-seven patients underwent conventional angiography and the bilateral femoral MR angiographic examination. Two-dimensional time-of-flight angiography was used for all studies. RESULTS: The femoral MR angiogram could have replaced the conventional angiogram in 57% of patients (21 of 37). In 43% of patients (16 of 37), the femoral MR angiogram could not have replaced the conventional angiogram. Reasons for diagnostic failure with femoral MR angiography included artifact from vascular clips (n = 8) or prosthetic joints (n = 3), overlooked distal aortic stenosis (n = 1), and suboptimal definition of vessels (usually trifurcation vessels) owing to various causes (n = 8). Seven of the patients in this group had bypass grafts. CONCLUSION: Some of the current limitations of femoral MR angiography could be avoided by supplemental duplex sonography around prostheses and vascular clips. The other limitations will require advances in MR imaging techniques.

Identification of collagens isolated from bovine Descemet's membrane.

In this study collagens were isolated and identified from a morphologically pure preparation of bovine Descemet's membrane (DM) which was obtained by gentle scraping of the cornea, sieving and subsequent treatment with detergents. An alternative procedure of DM isolation with forceps resulted in stromal contamination of the preparation as verified by light and transmission electron microscopy, and gel electrophoresis. The amino acid profile of collagens isolated by pepsinization and salt precipitation from the pure sample was similar to the analysis of the intact bovine DM. Polyacrylamide gel electrophoresis of this collagen under non-reducing conditions resulted in five major bands: 300 000 daltons (300 K), 200 000 daltons (200 K), 100 000 daltons (100 K) and lower molecular weight fractions (50 K1 and 50 K2). Individual collagen chains were isolated from preparative polyacrylamide gels and characterized by 125I two dimensional peptide mapping patterns. This data suggests that (1) the majority of collagen fragments seen in bovine DM pepsin supernatant are derived from a single genetically distinct collagen molecule, and (2) that type I and V collagens are not major components of bovine DM.