Ultrasound Elastography in Musculoskeletal Radiology: Past, Present, and Future.

Ultrasound elastography (USE) is becoming an important adjunct tool in the evaluation of various musculoskeletal (MSK) traumatic conditions and diseases, with an increasing number of applications and publications in recent years. This rapidly evolving technique enhances the conventional ultrasound (US) examination by providing information on the elastic properties of tissue alongside the morphological and vascular information obtained from B-mode US and Doppler imaging. Those performing USE must have basic knowledge of its proper imaging techniques and limitations. In this review article, we place the USE in historical perspective and discuss basic techniques and current applications of USE in the evaluation of various traumatic and pathologic conditions of fasciae, nerves, muscles, tendons, ligaments, and MSK soft tissue masses.

Carpal tunnel syndrome assessment with diffusion tensor imaging: Value of fractional anisotropy and apparent diffusion coefficient.

OBJECTIVES: To quantitatively assess carpal tunnel syndrome (CTS) with DTI by evaluating two approaches to determine cut-off values. METHODS: In forty patients with CTS diagnosis confirmed by nerve conduction studies (NCs) and 14 healthy subjects (mean age 58.54 and 57.8 years), cross-sectional area (CSA), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) at single and multiple levels with intraobserver agreement were evaluated. RESULTS: Maximum and mean CSA and FA showed significant differences between healthy subjects and patients (12.85 mm2 vs. 28.18 mm2, p < 0.001, and 0.613 vs. 0.524, p=0.007, respectively) (10.12 mm2 vs. 19.9 mm2, p<0.001 and 0.617 vs. 0.54, p=0.003, respectively), but not maximum and mean ADC (p > 0.05). For cut-off values, mean and maximum CSA showed the same sensitivity and specificity (93.3 %). However, mean FA showed better sensitivity than maximum FA (82.6 % vs. 73.9 %), but lower specificity (66.7 % vs. 80 %), and significant correlation for maximum CSA, 97 % (p < 0.01), with good correlation for maximum ADC and FA, 84.5 % (p < 0.01) and 62 % (p=0.056), respectively. CONCLUSIONS: CSA and FA showed significant differences between healthy subjects and patients. Single measurement at maximum CSA is suitable for FA determination. Key Points • DTI showed that FA is stronger than ADC for CTS diagnosis. • Single- and multiple-level approaches were compared to determine FA and ADC. • Single-level evaluation at the thickest MN cross-sectional area is sufficient.

Feasibility of Ultrasound-Guided Sacroiliac Joint Injections in Children Presenting with Sacroiliitis.

PURPOSE: To evaluate the feasibility and effectiveness of US-guided sacroiliac joint injection in the treatment of sacroiliitis in children. MATERIALS AND METHODS: This study was approved by the institutional review board and informed oral and written consent was obtained from the patients and their parents. In 13 patients (7 females and 6 males), 9 - 16 years (mean +/- std 11.39 +/-1.98), 18 sacroiliac joint (SI joint) injections were performed under US guidance. All patients suffered from severe sacroiliitis. US scanning was performed using a linear-array transducer operating at 5 - 18 MHz. Rating of the patients pain using a 0 - 10 dolorimetry scale on a visual analog score (VAS) was recorded before, immediately after and 3 months after injection to monitor severity and therapeutic response. RESULTS: Injection could be performed in all patients without complication and showed good response immediately and 3 months after the injection with a decrease of the VAS (from mean +/- std 9.44 +/- 1.097 to 3.89 +/- 3.82, p < 0.001 and to 0.56 +/- 1.097, p < 0.05, respectively). CONCLUSION: US-guided SI joint injection was feasible in all children, relatively quick and easy to perform and appeared effective in the treatment of children with sacroiliitis.

Precision of 3.0 Tesla quantitative magnetic resonance imaging of cartilage morphology in a multicentre clinical trial.

OBJECTIVE: Quantitative MRI (qMRI) of cartilage morphology is a promising tool for disease-modifying osteoarthritis drug (DMOAD) development. Recent studies at single sites have indicated that measurements at 3.0 Tesla (T) are more reproducible (precise) than those at 1.5 T. Precision errors and stability in multicentre studies with imaging equipment from various vendors have, however, not yet been evaluated. METHODS: A total of 158 female participants (97 Kellgren and Lawrence grade (KLG) 0, 31 KLG 2 and 30 KLG 3) were imaged at 7 clinical centres using Siemens Magnetom Trio and GE Signa Excite magnets. Double oblique coronal acquisitions were obtained at baseline and at 3 months, using water excitation spoiled gradient echo sequences (1.0x0.31x0.31 mm3 resolution). Segmentation of femorotibial cartilage morphology was performed using proprietary software (Chondrometrics GmbH, Ainring, Germany). RESULTS: The precision error (root mean square coefficient of variation (RMS CV)%) for cartilage thickness/volume measurements ranged from 2.1%/2.4% (medial tibia) to 2.9%/3.3% (lateral weight-bearing femoral condyle) across all participants. No significant differences in precision errors were observed between KLGs, imaging sites, or scanner manufacturers/types. Mean differences between baseline and 3 months ranged from <0.1% (non-significant) in the medial to 0.94% (p<0.01) in the lateral femorotibial compartment, and were 0.33% (p<0.02) for the total femorotibial subchondral bone area. CONCLUSIONS: qMRI performed at 3.0 T provides highly reproducible measurements of cartilage morphology in multicentre clinical trials with equipment from different vendors. The technology thus appears sufficiently robust to be recommended for large-scale multicentre trials.

Physical and exercise therapy for treatment of the rheumatoid hand.

OBJECTIVE: To study the short-term effects of physical therapy (ice massage or wax packs, thermal baths, and faradic hand baths) and exercise therapy on the rheumatoid hand. METHODS: The effect of individual physical therapy and exercise therapy programs was evaluated in 50 randomly selected rheumatoid arthritis inpatients (38 women and 12 men). Mean patient age (+/- SD) was 47.94 +/- 11.22 years, and mean disease duration was 5.04 +/- 4.80 years. The control group consisted of 50 randomly selected rheumatoid arthritis outpatients (37 women and 13 men; mean age 48.46 +/- 10.65 years, mean duration of disease 5.23 +/- 4.89 years) who at the time of the investigation were not receiving any physical or exercise therapy. The clinical indices used for evaluation of inflammation included erythrocyte sedimentation rate (ESR), pain intensity, proximal interphalangeal (PIP) joint size, and Ritchie articular index. Hand grip strength, palmar tip-to-tip and key pinch finger strength, finger range of motion, and activities of daily living (ADL) were the parameters used to assess the functional hand status. The study was single-blinded and of 3 weeks duration. RESULTS: In the physical therapy treated group, there was an improvement for most of the observed indices from baseline parameters that achieved statistical significance (P < 0.01 and P < 0.005) after the 3-week study period. ESR and PIP joint size improved clinically but failed to reach statistical significance. Patients had a more significant improvement in hand pain, joint tenderness, and ADL score (P < 0.005) than in range of motion (P < 0.01). All parameters in the control group slightly deteriorated over the study period. CONCLUSION: At least in the short term, physical and, particularly, exercise therapy produce a favorable improvement in the functional status of the rheumatoid hand.

Sonography of the glenoid labrum: a cadaveric study with arthroscopic correlation.

OBJECTIVE: We assessed the usefulness of sonography in evaluating the glenoid labrum in cadaveric specimens using arthroscopy as a standard of reference. MATERIALS AND METHODS: Eighty labral quadrants in 20 cadaveric shoulders were examined by two musculoskeletal radiologists using 5- to 7-MHz linear and curvilinear transducers. Agreement was reached by consensus. After sonography, arthroscopy was performed by an experienced orthopedic surgeon. Each labral quadrant was classified at the time of sonography and arthroscopy as normal, degenerated, or torn. RESULTS: Concordance between sonography and arthroscopy was 86% (69/80 quadrants). In differentiating abnormal labrum (tear or degeneration) from normal labrum using sonography, sensitivity was 63%, specificity was 98%, positive predictive value was 94%, negative predictive value was 86%, and accuracy was 88%. In differentiating labral tears from other labral conditions (degeneration or normality), sensitivity was 67%, specificity was 99%, positive predictive value was 67%, negative predictive value was 99%, and accuracy was 98%. CONCLUSION: Sonography has a promising role in the evaluation of the glenoid labrum, particularly in excluding labral tears when the labra appear normal on sonography. Further studies are required using normal and symptomatic patients to determine the usefulness of sonography in the diagnosis of labral abnormalities.

Power Doppler sonography in the assessment of musculoskeletal fluid collections.

OBJECTIVE: Power Doppler sonography is a relatively new technique that has been shown to depict hyperemia associated with musculoskeletal inflammatory disease. We performed this study to evaluate the ability of power Doppler sonography to differentiate musculoskeletal fluid collections of varying etiologies. SUBJECTS AND METHODS: Gray-scale and power Doppler sonography were performed on 39 patients with joint effusions or appendicular fluid collections. Blood flow (hyperemia) in the soft tissues adjacent to the fluid collections was subjectively analyzed and graded on a scale of 1 to 4 (1, normal flow; 2-4, increasing degrees of hyperemia). All fluid collections were aspirated within 24 hr of the sonographic examination. We found 31 joint effusions and 12 periarticular collections with appropriate imaging and pathologic correlation. RESULTS: Adjacent to 36 effusions and fluid collections, we saw moderate or marked hyperemia. Thirty-five of the 36 had an inflammatory or neoplastic cause, including 15 infected collections. One fluid collection had a degenerative etiology (subdeltoid bursitis secondary to supraspinatus tendon tear). Adjacent to the seven remaining effusions and fluid collections, we saw normal or mildly increased hyperemia; none of these collections had an inflammatory etiology. CONCLUSION: Power Doppler sonography helps distinguish inflammatory and infectious musculoskeletal fluid collections from those that are noninflammatory, and it may help guide the decision to perform diagnostic aspiration. Power Doppler sonography does not reliably differentiate between inflammatory collections of infectious and noninfectious origin because collections of either origin may significantly increase adjacent soft-tissue perfusion.