Andrea B. Rosskopf

Quantitative Shear-Wave US Elastography of the Supraspinatus Muscle: Reliability of the Method and Relation to Tendon Integrity and Muscle Quality

PURPOSE To evaluate the reliability of ultrasonographic (US) elastography of the supraspinatus (SSP) muscle, define normal shear-wave velocity (SWV) values, and correlate findings with tendon integrity and muscle quality. MATERIALS AND METHODS The study was approved by the local ethics committee, and written informed consent was obtained from all patients. SSP SWV (in meters per second) was prospectively assessed twice in 22 asymptomatic volunteers (mean age ± standard deviation, 53.8 years ± 15.3; 11 women and 11 men) by two independent examiners by using shear-wave elastography. Forty-four patients (mean age, 51.9 years ± 15.0; 22 women and 22 men) were prospectively included. SWV findings were compared with tendon integrity, tendon retraction (Patte classification), fatty muscle infiltration (Goutallier stages 0-IV), and muscle volume atrophy (tangent sign) on magnetic resonance (MR) images. Descriptive statistics, Spearman correlation, analysis of variance, two-sample t test, and intraclass correlation coefficient (ICC) were used. RESULTS Test-retest reliability for mean total SWV (MTSWV) was good for examiner 1 (ICC = 0.70; 95% confidence interval [CI]: 0.30, 0.87; P = .003) and excellent for examiner 2 (ICC = 0.80; 95% CI: 0.53, 0.92; P < .001). Interexaminer reliability was excellent (ICC = 0.89; 95% CI: 0.64, 0.96; P < .001). MTSWV in volunteers (3.0 m/sec ± 0.5) was significantly higher than that in patients (2.5 m/sec ± 0.5; P = .001). For tendon integrity, no significant difference in MTSWV was found. For tendon retraction, MTSWV varies significantly between patients with different degrees of retraction (P = .047). No significant differences were found for Goutallier subgroups. MTSWV was significantly lower with a positive tangent sign (P = .015; n = 10). CONCLUSION Shear-wave elastography is reproducible for assessment of the SSP muscle. Mean normal SSP SWV is 3.0 m/sec ± 0.5. SWV decreases with increasing fat content (Goutallier stage 0-III) and increases in the final stage of fatty infiltration (Goutallier stage IV).

Femoral and tibial torsion measurement in children and adolescents: comparison of 3D models based on low-dose biplanar radiography and low-dose CT.

OBJECTIVE The purpose of this study was to evaluate the interchangeability and reliability of femoral and tibial torsion measurements in children using 3D models based on biplanar radiography compared with CT measurements. MATERIALS AND METHODS Femoral and tibial torsion were measured in 50 patients (mean age, 10.9 years; range, 4.7-14.8 years) using 3D models based on low-dose biplanar radiography by two independent readers. Measurements on transverse CT images by two independent readers served as the reference standard. Intermethod and interreader agreement was calculated using descriptive statistics, intraclass correlation coefficient (ICC), and Bland-Altman analysis. RESULTS Femoral and tibial torsion were -6°-65° and 6°-51° for 3D models based on biplanar radiography and -13°-59° and 4°-52° for CT measurements. The average difference (±SD) between the two methods was 4.9°±3.8° and 5.5°±4.1°, respectively. The intermethod ICC for biplanar radiography was 0.90 (95% CI, 0.87-0.92) for femoral torsion and 0.75 (0.68-0.80) for tibial torsion. The interreader ICC was 0.93-0.97. Mean measurement differences between the two biplanar radiography readers were 3.4° (0.0°-11.0°) for femoral torsion and 3.9° (0.0°-15.0°) for tibial torsion. Mean interreader differences at CT were 3.3° (0.0°-9.0°) for femoral and 3.0° (0.0°-10.0°) for tibial torsion. There was no trend for larger intermethod differences with decreasing age of the children. CONCLUSION Femoral and tibial torsion measurements in children using 3D models based on biplanar radiography are comparable to CT measurement results. Despite skeletal immaturity, torsion measurements in children on biplanar radiography seem to be as reliable as those on CT images.

Delayed-Onset Muscle Soreness: Temporal Assessment With Quantitative MRI and Shear-Wave Ultrasound Elastography

OBJECTIVE The objective of our study was to assess delayed-onset muscle soreness (DOMS) over time using quantitative MRI and shear-wave ultrasound (US) elastography. SUBJECTS AND METHODS Five male (mean age ± SD, 39.6 ± 4.6 years) and five female (30.6 ± 13.5 years) volunteers underwent 1.5-T MRI before and after (15 minutes, 1 day, 3 days, 7 days) performing unilateral eccentric resistance exercise of the elbow flexor muscles. The MRI examinations included fluid-sensitive, DWI, and diffusion-tensor imaging sequences of the distal upper arm. Muscle edema, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were assessed. US of the brachialis muscle was performed before and after (15 minutes, 12 hours, 1 day, 2 days, 3 days, 7 days) exercise to measure mean shear-wave velocity (SWV). Pain and muscle tightness were assessed. RESULTS For men, muscle edema was moderate and peaked 3 days after exercise; for women, muscle edema was mild and peaked 1-3 days after exercise. ADC was highest 3 days after exercise in men (mean, 1809.22 × 10-6 mm2/s; before exercise, 1529.88 × 10-6 mm2/s) and women (1741.90 × 10-6 mm2/s; before exercise, 1475.80 × 10-6 mm2/s). FA dropped from 361.00 in men and 389.00 in women before exercise to a minimum of 252.12 and 321.28, respectively, 3 days after exercise. Mean SWV increased after exercise in men (before exercise, 3.00 ± 0.30 m/s; peak [15 minutes after exercise], 4.04 ± 0.90 m/s) and women (before, 2.82 ± 0.40 m/s; peak [1 day after exercise], 3.23 ± 0.40 m/s) and subsequently returned to normal. In men, the ADC values of the brachialis muscle positively correlated with mean SWV (r = 0.92, p = 0.028). FA negatively correlated with pain in men (r = -0.993, p = 0.001) Muscle edema outlasted clinical symptoms in most volunteers. CONCLUSION FA inversely correlates with pain and may be a useful imaging parameter for assessment of DOMS. Shear-wave US elastography shows a temporary increase of muscle stiffness after DOMS-inducing exercise but does not correlate with quantitative MRI parameters or clinical symptoms.

Beyond the alpha angle: Alternative measurements for quantifying cam-type deformities in femoroacetabular impingement

To assess alternative measurements to the alpha angle as a tool for distinguishing between symptomatic and asymptomatic cam‐type deformities of the femoral head.

Quality Management in Musculoskeletal Imaging: Form, Content, and Diagnosis of Knee MRI Reports and Effectiveness of Three Different Quality Improvement Measures

OBJECTIVE The purpose of this article is to evaluate the quality of reports of knee MRI examinations in form, content, and diagnosis and to assess the effect of three different quality improvement measures. MATERIALS AND METHODS Reports of 500 knee MRI examinations (first round, or baseline) were reviewed retrospectively by five musculoskeletal radiologists. Fifteen different criteria were assessed for formal and content-related quality of reports. Diagnostic discrepancies were categorized using a 5-point scale, as follows: I, no deviation; II, undetected finding, clinically irrelevant; III, wrong interpretation of finding, clinically irrelevant; IV, undetected finding, clinically relevant; and V, wrong interpretation of finding, clinically relevant. Then three different quality improvement measures were applied prospectively to a total of 510 consecutive reports: a quiet work environment, double reading, and the use of a structured report template. These 510 knee MRI reports (second round) were evaluated using the same criteria. RESULTS A statistically significant improvement in 13 of 15 criteria was found in the second-round reports: orthographic errors improved from 32.4% to 22.0% (p < 0.001) of reports and digital speech recognition errors improved from 8.4% to 7.6% (p = 0.660). Missing anatomic structures decreased from 6.3% to 0.4%. Diagnostic discrepancies were less frequently found (12.9% vs 20.8%; p = 0.001), along with the following changes in categorization (first-round results are in parentheses): I, 87.1% (79.2%); II, 9.2% (16.8%); III, 2.3% (1.0%); IV, 1.0% (2.6%); and V, 0.4% (0.4%). Quality improvement was found in all three measure groups, without statistical significance among the groups, except for the orthographic errors (p < 0.001), which were most common in the template group. CONCLUSION All three quality improvement measures significantly improved the quality of the knee MRI reports, but no measure was clearly superior to the others.

MRI Predictors of Posterolateral Corner Instability: A Decision Tree Analysis of Patients with Acute Anterior Cruciate Ligament Tear

Purpose To determine the diagnostic performance of MRI for helping to predict posterolateral knee instability in patients with acute anterior cruciate ligament (ACL) tear. Materials and Methods This retrospective cohort study was performed in a consecutive series of 162 patients (mean age, 32.8 years ± 10.0 [standard deviation]; 95 men [mean age, 31.0 years ± 9.6] and 67 women [mean age, 35.4 years ± 10.0]) who underwent ACL reconstruction with (n = 19) or without (n = 143) concomitant posterolateral corner (PLC) reconstruction between June 2014 and February 2017. MR images were evaluated by two radiologists. Diagnostic performance of imaging findings was calculated. Clinical evidence of posterolateral instability requiring PLC reconstruction served as reference standard. The most significant predictors of posterolateral instability were determined with decision tree analysis. Results In patients with and without PLC reconstruction, respectively, the lateral collateral ligament was completely torn in 10 of 19 (52.6%) and seven of 143 (4.9%) patients; the posterior cruciate ligament in two of 19 (10.5%) and five of 143 (3.5%) patients; the popliteus tendon in three of 19 (15.8%) and none of 143 (0%) patients; and the biceps femoris tendon in four of 19 (21.1%) and none of 143 (0%) patients (data for reader 1). The smaller structures of the PLC were not constantly viewable. Complete tear or avulsion of the lateral collateral ligament was more frequent in patients who needed PLC reconstruction (P < .001), and decision tree analysis revealed that this finding was the most statistically significant predictor of posterolateral instability. Instability was correctly predicted in 147 of 162 patients (90.7%) by reader 1 and 151 of 162 patients (93.2%) by reader 2. Conclusion Complete tear or avulsion of the lateral collateral ligament was the most significant predictor at MRI of posterolateral instability. Assessment of the smaller posterolateral corner structures did not improve diagnostic performance.

Femoral Torsion Assessment with MRI in Children: Should we use the Bony or Cartilaginous Contours?

OBJECTIVE To assess whether the use of cartilaginous contours at the femoral condyles instead of bony contours significantly changes femoral torsion measurements in children. MATERIALS AND METHODS Femoral torsion was measured in 32 girls (mean age 10.1 years±2.3 standard deviation) and 42 boys (10.9 years±2.5) on axial magnetic resonance (MR) images by two independent readers (R1,R2). The femoral condyle angle was measured using each the cartilaginous and bony contours of the distal femur. Cartilage thickness at femoral condyles was assessed. Intraclass-correlation-coefficient (ICC) and Pearsons correlation were used for statistical analysis. RESULTS Mean difference between cartilaginous and bony femoral torsion in girls was -1.1°±1.75 (range, -5.4° to 3.1°) for R1 and -1.64°±1.67 (-6.3° to 2.1°) for R2, in boys -1.5°±1.87 (-8.4° to 1.1°) for R1 and -2.28°±1.48 (-4.3° to 9.7°) for R2. Weak-to-moderate correlations between difference of cartilaginous-versus-bony measurements and cartilage thickness (r=-0.15 to -0.55, P<0.001-0.46) or age (r=-0.33 to 0.46, P<0.001-0.006) were found for both genders. Intermethod-ICC for cartilaginous versus bony femoral torsion measurements was 0.99/0.99 for R1/R2 in girls, and 0.99/0.98 in boys. CONCLUSION There is only a small difference when measuring femoral torsion through cartilaginous versus bony contours, and no major difference in this between boys and girls.

Sonografie des normalen Gewebes

In diesem Kapitel erhalt der Leser eine genaue Beschreibung der typischen Darstellung des normalen Gewebes (Sehnen, Bander, Nerven, Muskeln, Knorpel etc.) im Ultraschall anhand zahlreicher Bildbeispiele. Es werden alle wichtigen anatomischen Strukturen und deren Normvarianten im Detail beschrieben – vom distalen Unterarm, uber Handgelenk/Karpaltunnel bis zu den Fingerspitzen. Desweiteren werden die einzelnen Standardpositionen zur Ultraschalluntersuchung von Hand und Handgelenk vorgestellt. Das Kapitel enthalt hilfreiche Praxistipps inklusive moglicher »pitfalls« fur den sonografischen Anfanger.