Evaluation of the Transverse Sinus by Magnetic Resonance Venography: Limitations-An Illustrative Case Report

Many techniques of magnetic resonance angiography depend on flow velocity. The broad normal range of venous flow velocities and preferential patterns of drainage, particularly in the transverse sinuses, may produce images that are diagnostically misleading. This reports such a case, with samples of various flow patterns in the transverse sinuses of other individuals, as demonstrated by one magnetic resonance angiographic technique (time-of-flight).     

Correlations of nuclear magnetic resonance imaging, computerized tomography, and clinical profiles in multiple sclerosis

Nuclear magnetic resonance (NMR) imaging was superior to CT for imaging the brain lesions of 27 patients with MS. The incidence of abnormal examinations was 78% by NMR and 63% by CT. In cases in which both studies were abnormal, NMR usually demonstrated many more lesions and more extensive involvement than CT. The appearance and locations of lesions identified by NMR were similar to those of autopsy studies of MS and may be relatively specific for this disease. Some lesions identified by CT disappeared during serial examinations, but lesions identified by NMR did not resolve over time. Seventy-five percent of the lesions were clinically "silent"; only 5% were definitely related to the clinical symptoms and signs. All of those lesions were located in the brainstem or cerebellar peduncles and were identified by NMR, but missed by CT.     

Thrombotic thrombocytopenic purpura: brain CT and MRI findings in 12 patients

Clinical-neuroimaging analysis of 12 thrombotic thrombocytopenic purpura (TTP) patients revealed a variety of brain lesions. These included reversible cerebral edema lesions with MRI features of reversible posterior leukoencephalopathy syndrome (RPLS). Most of the RPLS patients had hypertension and renal dysfunction, suggesting RPLS due to hypertensive encephalopathy. Prompt treatment usually led to neurologic recovery and disappearance of edematous lesions. Those with infarcts or hematomas had a poorer outcome. TTP should be added to the expanding spectrum of RPLS and hypertensive encephalopathy.     

MR imaging of the breast in patients with positive margins after lumpectomy: influence of the time interval between lumpectomy and MR imaging

OBJECTIVE: Postsurgical contrast enhancement resulting from inflammatory changes at the site of surgery limits the accuracy of MR imaging of the breast in diagnosing residual breast cancer. This study was undertaken to evaluate the influence of the time interval between lumpectomy and MR imaging on the diagnosis of residual breast cancer. MATERIALS AND METHODS: Sixty-eight patients who had undergone excisional biopsy with positive resection margins underwent MR imaging for evaluation of residual breast cancer and possible breast conservation. Patients were retrospectively stratified according to the time interval between lumpectomy and MR imaging. Dynamic and morphologic enhancement features were used for lesion characterization. Imaging findings were correlated with results of histopathology. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for patients waiting 7, 14, 21, 28, 35, and 42 days after initial surgery before undergoing MR imaging of the breast. RESULTS: The time interval between lumpectomy and MR imaging of the breast had the greatest influence on the specificity and negative predictive value of MR imaging, increasing progressively over time. A plateau of highest values of 75% specificity and 86% negative predictive value was reached at 28 and 35 days after surgery, respectively. Although the sensitivity and positive predictive value showed smaller variations over time, peak values of 95% sensitivity and 92% positive predictive value were obtained at 35 and 28 days after surgery, respectively. CONCLUSION: We recommend scheduling patients with positive resection margins no earlier than 28 days after initial surgery for evaluation of residual cancer using MR imaging of the breast.     

Plasma and synovial fluid meclofenamic acid concentrations in patients with rheumatoid arthritis of the knee

Summary We have measured plasma and synovial fluid concentrations of meclofenamic acid at 2, 4, 8, and 12 h during steady-state administration (100 mg three times daily for 4–7 days). Paired plasma and synovial samples were obtained pre-treatment and at one of the above times in twelve patients with a diagnosis of rheumatoid arthritis. In addition, the extent of protein binding of meclofenamic acid was assessed in vitro in the pre-treatment plasma and synovial fluid specimens.Peak total concentrations of 1.73 and 0.86 µg·ml^–1 were observed in plasma (at 2 h) and synovial fluid (at 4 h) respectively. The extent of protein binding was 99.7 and 99.6% (not significantly different) in plasma and synovial fluid respectively.The results of this study are compared to those from similar reported studies of other nonsteroidal anti-inflamatory compounds.     

Reliability of transcutaneous measurement of oxygen tension on the lower leg

AIM: Measurement of transcutaneous oxygen tension is increasingly used to determine the appropriate level of amputation in patients with vascular disease. The purpose of the present study was to analyze the intra- and interrater reliability of transcutaneous oxygen [tcpO (2)] measurements in a homogeneous study group. METHOD: Five investigators assessed the transcutaneous oxygen tension of both lower legs of seven persons in a fixed setting. Assessment was repeated with the same examiners and the same examinees after 24 hours. TcpO (2) was measured at the posterior aspect of the lower leg twenty centimeters below the knee joint line. The TCM 400 Monitoring System (Radiometer Medical AIS, Bronshoj, Denmark) was used. Statistical analysis of the intra- and interrater reliability was performed with the Spearman coefficient of correlation. RESULTS: An overall mean of 56.2 +/- 10.6 mmHg was found. For the first examination, a mean of 55.3 +/- 10.6 mmHg was observed, whereas for the second examination it was 57.0 +/- 10.5 mmHg. Analysis of intrarater reliability showed a coefficient of correlation of r (s) = 0.56 (p < 0.0001). For interrater reliability, we found coefficients of correlation ranging from r (s) = 0.20 (p = 0.20) to r (s) = 0.69 (p = 0.0004). CONCLUSION: Analysis of transcutaneous oxygen tension measurements performed by different investigators in a fixed setting revealed a non- homogeneous intra- and interrater reliability, which should be taken into account prior to initiating therapy.     

Outcome assessment in total knee arthroplasty: is the clinical measurement of range of motion a reliable measurable outcome variable?

AIM: The aim of this clinical study was to investigate the reliability of the clinical assessment (visual and goniometric) of the range of motion of the knee joint. METHOD: 30 patients were assessed concerning the range of motion of their knee joints by visual and goniometric measurements. Assessment was performed by three investigators. The obtained data were used to analyse the intra- and interobserver reliability. Statistical analysis was performed using the Spearman coefficient of correlation [r (s)]. RESULTS: Intraobserver agreement was consistent across observers regarding the visual and goniometric assessment of flexion (r (s) > 0.6), whereas reliability was uniformly low for both measurements regarding the assessment of extension (r (s) < 0.6). Interobserver agreement was consistent across all three goniometric and two out of three visual assessments regarding the measurement of flexion (r (s) > 0.6); the interobserver reproducibility of extension, however, was uniformly low both for the visual and goniometric measurements (r (s) < 0.6). CONCLUSION: Reliability of clinical assessment of range of motion should be taken critically into consideration whilst performing classical function-related scoring systems when measuring outcome after total joint arthroplasty, since these scoring systems are strongly based on a valid and reliable assessment of range of motion.     

Indeterminate ovarian mass at US: incremental value of second imaging test for characterization--meta-analysis and Bayesian analysis

PURPOSE: To compare value of current diagnostic strategies in assessment of changes in posttest probability of ovarian cancer when menopausal status and combination and sequence of diagnostic imaging tests are considered. MATERIALS AND METHODS: Prevalence of ovarian cancer according to menopausal status in women with an ovarian mass and performance of combined gray-scale and Doppler ultrasonography (US), computed tomography (CT), and non-enhanced magnetic resonance (MR) imaging and contrast material-enhanced MR imaging after indeterminate results at gray-scale US were derived from meta-analysis by using MEDLINE database and institutional data. Study was approved by the institutional review board of University Hospital Geneva, Geneva, Switzerland; informed consent was waived. Posttest probability values were computed through Bayesian analysis and Monte Carlo simulation after initial gray-scale US and secondary combined gray-scale and Doppler US, CT, or MR imaging, while dependence of test results among imaging modalities was considered. Changes in posttest probability were compared among imaging modalities with summary receiver operating characteristic curves. RESULTS: Prevalence of ovarian cancer was 8.75% in premenopausal women and 32.40% in postmenopausal women with an ovarian mass. After characterization with initial gray-scale US, posttest probability in pre- and postmenopausal women changed, respectively, to 25% and 63% for indeterminate results and to 2% and 7% for benign results. Subsequent use of combined gray-scale and Doppler US, CT, or MR imaging had significant higher positive and lower negative posttest probability than did use of gray-scale US alone. In women with an indeterminate initial US result, posttest probability decreased after secondary testing with benign results for all imaging modalities to 2% in premenopausal women and to 8%-10% in postmenopausal women. After secondary testing for suspicious lesions, posttest probability increased more after non-enhanced (premenopausal women, 70%; postmenopausal women, 92%) or contrast-enhanced MR imaging (premenopausal women, 80%; postmenopausal women, 95%) than it did after combined gray-scale and Doppler US (premenopausal women, 30%; postmenopausal women, 69%) or CT (premenopausal women, 38%; postmenopausal women, 76%) (P < .001). CONCLUSION: In women with an indeterminate ovarian mass at gray-scale US, MR imaging results contributed to change in probability of ovarian cancer in both pre- and postmenopausal women more than did CT or combined gray-scale and Doppler US results.