Biomedical subjects

Lynne Steinbach

Publications and source records attributed to Lynne Steinbach.

7 recordsLinked to original sources

PubMed2006

MR imaging of the ankle at 3 Tesla and 1.5 Tesla: protocol optimization and application to cartilage, ligament and tendon pathology in cadaver specimens.

The objective of this study was to optimize ankle joint MR imaging in volunteers at 1.5 Tesla (T) and 3.0 T, and to compare these optimized sequences concerning image quality and performance in assessing cartilage, ligament and tendon pathology in fresh human cadaver specimens. Initially our clinical ankle protocol consisting of T1-weighted (-w), fat-saturated (fs) T2-w, and short tau inversion-recovery fast spinecho (FSE) sequences was optimized at 1.5 T and 3.0 T by two radiologists. For dedicated cartilage imaging, fs-intermediate (IM)-w FSE, fs spoiled gradient echo, and balanced free-precession steady-state sequences were optimized. Using the optimized sequences, thirteen cadaver ankle joints were imaged. Four radiologists independently assessed these images concerning image quality and pathology. All radiologists consistently rated image quality higher at 3.0 T (all sequences p<0.05). For detecting cartilage pathology, diagnostic performance was significantly higher at 3.0 T (ROC-values up to 0.93 vs. 0.77; p<0.05); the fs-IM FSE sequence showed highest values among the different sequences. Average sensitivity for detecting tendon pathology was 63% at 3.0 T vs. 41% at 1.5 T and was significantly higher at 3.0 T for 2 out of 4 radiologists (p<0.05). Compared to 1.5 T, imaging of the ankle joint at 3.0 T significantly improved image quality and diagnostic performance in assessing cartilage pathology.

Aged↗

PubMed2006

Magnetic resonance arthrography.

For decades, fluoroscopic arthrography was the only method available to image a joint with contrast enhancement. Advances in CT led to the natural development of CT arthrography. Development of MRI and its capability for multiplanar imaging led to direct magnetic resonance arthrography (MRA). This technique has been performed since 1987 and has surpassed CT arthrography in popularity in the United States. Indirect MRA developed subsequently to offer a less invasive alternative. This article presents an overview of direct MRA and addresses joint-specific issues regarding direct MRA. An overview of indirect MRA also is provided.

Arthrography↗

PubMed2005

Cartilage MR imaging at 3.0 versus that at 1.5 T: preliminary results in a porcine model.

PURPOSE: To compare 1.5- and 3.0-T magnetic resonance (MR) images of porcine knee specimens containing artificial cartilage lesions in terms of accuracy of lesion depiction, image quality, and signal-to-noise ratio (SNR). MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act-compliant study had institutional review board approval, and informed consent was obtained from the human volunteers. Two fat-saturated cartilage MR imaging sequences (an intermediate-weighted fast spin-echo [SE] sequence and a spoiled gradient-echo [GRE] sequence) were optimized for imaging at 3.0 T in two human volunteers and then used to image 10 porcine knees in which 29 artificial cartilage lesions had been created. Corresponding sequences were used at 1.5 T for all specimens. Images were assessed by two radiologists in consensus, and diagnostic performance in lesion depiction was determined by using macroscopic findings in specimen slices as a reference standard. SNRs were also calculated. For statistical analysis, the McNemar test of discordant pairs was used with a level of significance of P < .05. RESULTS: The best diagnostic performance for both the intermediate-weighted fast SE and the spoiled GRE sequences was achieved at 3.0 T. With use of corresponding fat-saturated intermediate-weighted fast SE sequences with an identical acquisition time (9 minutes 44 seconds), 26 (90%) of 29 lesions were detected at 3.0 T, while 18 (62%) were detected at 1.5 T. With use of fat-saturated spoiled GRE sequences, 24 (83%) of 29 lesions were detected at 3.0 T (acquisition time, 8 minutes 48 seconds), and 23 (79%) lesions were detected at 1.5 T (acquisition time, 11 minutes 14 seconds). The rate of correct lesion grade assessment was 65% (17 of 26 lesions) at 3.0 T and 61% (11 of 18 lesions) at 1.5 T with the intermediate-weighted fast SE sequences and 83% (20 of 24 lesions) at 3.0 T and 70% (16 of 23 lesions) at 1.5 T with the spoiled GRE sequences. Both subjective evaluation of image quality and SNR values were significantly higher at 3.0 T (P < .05). CONCLUSION: In this animal model, MR imaging at 3.0 T increased the accuracy of cartilage lesion assessment when compared with imaging at 1.5 T. Image quality and SNR were highest at 3.0 T.

Animals↗

PubMed2005

Value of FDG PET in the assessment of patients with multiple myeloma.

OBJECTIVE: Our objective was to evaluate if whole-body PET with FDG is able to detect bone marrow involvement in patients with multiple myeloma and to assess its appearance and distribution pattern. MATERIALS AND METHODS: Seventeen whole-body FDG PET scans were performed in 13 patients with multiple myeloma. Four patients were referred for evaluation of extent of disease pretherapy and nine patients were referred for assessment of therapy response (chemotherapy, radiation therapy, bone marrow transplant). FDG PET images were evaluated for distribution and uptake pattern. Standardized uptake values were obtained to quantify FDG uptake. Results of other imaging examinations (MRI, CT, radiography), laboratory data, biopsies, and the clinical course were used for verification of detected lesions. RESULTS: FDG PET was able to detect medullary involvement of multiple myeloma. There were two false-negative results. In one patient, the radiographic skeletal survey showed subcentimeter lytic lesions within the ribs that were not detected on FDG PET and in the other patient, a lytic lesion detected on radiographs showed only mildly increased FDG uptake that was not identified prospectively. There was one false-positive FDG PET result in a patient who had undergone radiation therapy 3 weeks before PET. FDG PET was helpful in differentiating between posttherapeutic changes and residual/recurrent tumor and in assessing response to therapy. FDG PET resulted in upstaging of disease in four patients, which influenced subsequent management and prognosis. Sensitivity of FDG PET in detecting myelomatous involvement was 85% and specificity was 92%. CONCLUSION: FDG PET is able to detect bone marrow involvement in patients with multiple myeloma. FDG PET is useful in assessing extent of disease at time of initial diagnosis, contributing to staging that is more accurate. FDG PET is also useful for evaluating therapy response.

Adult↗

PubMed2005

Optimization of gadodiamide concentration for MR arthrography at 3 T.

OBJECTIVE: The purpose of our study was to determine the optimal concentration of a gadolinium-based contrast agent (gadodiamide) for direct MR arthrography at 3 T compared with 1.5 T in an in vitro study. CONCLUSION: Optimized concentrations of gadolinium-based contrast agents for MR arthrography are similar at 3 and 1.5 T, although a slightly greater dilution may be useful at 3 T. Signal-to-noise ratio peak levels are significantly reduced by adding an iodinated contrast agent, relatively significantly more at 3 T than at 1.5 T.

Arthrography↗

PubMed2004

MR imaging of tendon abnormalities of the elbow.

Tendon injuries about the elbow are among the most commonly encountered pathology in this articulation. These injuries are often the result of chronic repetitive microtrauma but can be seen in the setting of acute trauma. This article focuses on the imaging diagnosis of tendon pathology in the elbow and the associated findings that can be seen with tendon injury. A detailed understanding of common pathology and patterns of injury can facilitate the ease and accuracy of imaging diagnosis.

Humans↗

PubMed2002

Magnetic resonance imaging of normal and osteoarthritic trabecular bone structure in the human knee.

OBJECTIVE: To use high-resolution magnetic resonance imaging (MRI) to evaluate the trabecular bone structure in the distal femur and the proximal tibia and its to correlate the findings with different stages of osteoarthritis (OA) of the human knee. METHODS: Axial images of the distal femur and proximal tibia were obtained at 1.5 T in patients without and with mild OA and with severe OA. The spatial resolution was 195 x 195 microm(2) with a 1-mm slice thickness. Apparent measures of trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular separation (Tb.Sp), and trabecular thickness (Tb.Th) were calculated. RESULTS: Significant differences existed in the trabecular bone structure of the femur and tibia. Differences in trabecular bone structure between the tibia and the femur decreased with the degree of OA. The apparent BV/TV, Tb.N, and Tb.Sp in the femoral condyles could be used to differentiate healthy patients or patients with mild OA from patients with severe OA (P < 0.05). Among individuals, the structural variation of the lateral and medial femoral condyle was indicative of the extent of the disease. CONCLUSION: High-resolution MRI of the knee joint can provide a noninvasive assessment of trabecular bone structure. Trabecular bone structure, determined by high-resolution MRI, shows significant variation in patients with varying degrees of OA. The impact of OA on trabecular bone is different in the tibia than in the femur, and this difference depends on the extent of the disease.

Adult↗