MR Arthrography of the Hip: Comparison of IDEAL-SPGR Volume Sequence to Standard MR Sequences in the Detection and Grading of Cartilage Lesions
ABSTRACT To compare the diagnostic performance of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL)-spoiled gradient-recalled echo (SPGR) with that of standard magnetic resonance (MR) arthrography sequences for detecting and grading cartilage lesions within the hip joint during MR arthrography.
Following institutional review board approval, 67 consecutive hip MR arthrograms were retrospectively reviewed independently by three musculoskeletal radiologists and one musculoskeletal fellow. IDEAL-SPGR images and the two-dimensional images, the latter from the routine MR arthrography protocol, were evaluated at separate sittings to grade each articular surface of the hip joint. By using arthroscopy as the reference standard, the sensitivity and specificity of the two techniques for detecting and grading cartilage lesions were determined. The McNemar test was used to compare diagnostic performance. Interreader agreement was calculated using Fleiss κ values.
For all readers and surfaces combined, the sensitivity and specificity for detecting cartilage lesions was 74% and 77%, respectively, for IDEAL-SPGR and 70% and 84%, respectively, for the routine MR arthrography protocol. IDEAL-SPGR had similar sensitivity (P = .12) to and significantly lower specificity (P < .001) than the routine MR arthrography protocol for depicting cartilage lesions. When analyzing the differences in sensitivity and specificity by reader, the two readers who had experience with IDEAL-SPGR had no significant difference in sensitivity and specificity for detecting cartilage lesions between the two sequences. For all readers and surfaces combined, IDEAL-SPGR had a higher accuracy in correctly grading cartilage lesion (P = .012-.013). Interobserver agreement for detecting cartilage lesions did not differ between the two techniques.
IDEAL-SPGR had similar sensitivity and significantly lower specificity for detecting cartilage lesions and higher accuracy for grading cartilage lesions than did a routine MR arthrography protocol; the lower specificity of IDEAL-SPGR for detecting cartilage lesions was not seen in experienced readers.
[Show abstract] [Hide abstract]
ABSTRACT: Rationale and Objectives: To evaluate the feasibility of a modified approach for direct magnetic-resonance (MR) arthrography of the hip under leg traction in achieving a sufficient femoroacetabular interface and improving the visualization of the ligamentum teres. Materials, and Methods : Forty-six MR arthrograms of 44 patients Who underwent MR arthrography with and without leg traction were included into the study. Traction approach included injection of 18-27 mL of fluid (local anesthetic, contrast agent), application of weight-adapted traction load (15-23 kg), and the use of a supporting plate. Patients were instructed to report on pain and Complications with an integer pain scale. Joint distraction was measured on coronal images obtained with and without traction, and two radiologists independently evaluated whether femoroacetabular cartilage layers and the ligamentum teres could be seen as distinct-entities. McNemar test was used and interobserver agreement was assessed. Results: No patient asked for termination of the examination. There ware no cases of neuropraxia. Mean difference in distraction, was 3.7 mm/3.6 mm (reader 1/reader 2). Cartilage layers could be seen as distinct entities in 43/43 (93.5%/93.5%) and 6/8 (13%/17.4%) of the joints with/without traction (p < .001/P < .001), respectively. The ligamentum teres could be differentiated in 33/30.(71.7%/65.2%) cases with traction, in 33/30 (71.7%/65.2%) cases without traction (P < .999/P < .999), and in 40/37 (87%/80.4%) Cases with both the techniques combined. Conclusions: Traction MR arthrography is safe and technically feasible. It enabled the differentiation between femoroacetabular cartilage layers in most cases. Visualization of the ligamentum teres was optimal by combining imaging with both modalities.Academic Radiology 06/2014; 21(10). DOI:10.1016/j.acra.2014.04.014 · 2.08 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Purpose To evaluate the ability of T2* mapping to help differentiate damaged from normal acetabular cartilage in patients with femoroacetabular impingement (FAI). Materials and Methods The institutional review board approved this retrospective study, and the requirement to obtain informed consent was waived. The study complied with HIPAA guidelines. The authors reviewed T2* relaxation time maps of 28 hips from 26 consecutive patients (mean patient age, 28.2 years; range, 12-53 years; eight male patients (nine hips) with a mean age of 26.7 years [range, 16-53 years]; 18 female patients (19 hips) with a mean age of 28.9 years [range, 12-46 years]). Conventional diagnostic 3.0-T magnetic resonance (MR) arthrography was augmented by including a multiecho gradient-recalled echo sequence for T2* mapping. After imaging, acetabular and femoral data were separated and acetabular regions of interest were identified. Arthroscopic cartilage assessment with use of a modified Beck scale for acetabular cartilage damage was performed by an orthopedic surgeon who was blinded to the results of T2* mapping. A patient-specific acetabular projection with a T2* overlay was developed to anatomically correlate imaging data with those from surgery (the standard of reference). Results were analyzed by using receiver operating characteristic (ROC) curves. Results The patient-specific acetabular projection enabled colocalization between the MR imaging and arthroscopic findings. T2* relaxation times for normal cartilage (Beck score 1, 35.3 msec ± 7.0) were significantly higher than those for cartilage with early changes (Beck score 2, 20.7 msec ± 6.0) and cartilage with more advanced degeneration (Beck scores 3-6, ≤19.8 msec ± 5.6) (P < .001). At ROC curve analysis, a T2* value of 28 msec was identified as the threshold for damaged cartilage, with a 91% true-positive and 13% false-positive rate for differentiating Beck score 1 cartilage (normal) from all other cartilages. Conclusion The patient-specific acetabular projection with a T2* mapping overlay enabled good anatomic localization of cartilage damage defined with a T2* threshold of 28 msec and less. © RSNA, 2014.Radiology 02/2014; DOI:10.1148/radiol.13131837 · 6.21 Impact Factor
Article: Review: Femoroacetabular ImpingementArthritis & Rheumatology 01/2015; DOI:10.1002/art.38887 · 7.48 Impact Factor