Improved Visualization of Juxtaprosthetic Tissue Using Metal Artifact Reduction Magnetic Resonance Imaging: Experimental and Clinical Optimization of Compressed Sensing SEMAC

OBJECTIVES The purpose of this study was to identify an optimal imaging protocol for metal artifact reduced magnetic resonance imaging by application of different imaging and postprocessing parameters in compressed sensing slice-encoding for metal artifact correction (CS-SEMAC) and to test it in patients with total hip arthroplasty (THA). MATERIALS AND METHODS In an experimental setup, a phantom consisting of a standard THA embedded in gadolinium-containing agarose was scanned at 1.5 T. Pulse sequences included coronal short tau inversion recovery (STIR), T1-weighted (w), and T2-w CS-SEMAC sequences. All pulse sequences were acquired with 11, 19, and 27 slice-encoding steps (SESs), respectively. For each raw dataset, postprocessing was performed with variations of the parameters: (1) number of iterations (5, 10, 20, 30, 50) and (2) normalization factor (0.0005, 0.001, 0.002, 0.003, 0.005). Following, in clinical magnetic resonance scans of patients with THA, identical STIR, T1-w, and T2-w pulse sequences with 11 and 19 SESs were acquired and were postprocessed similarly with variations in parameters. Semiquantitative outcome measures were assessed on a 5-point scale (1 = best, 5 = worst). The overall best image quality was determined. Signal-to-noise ratio and contrast-to-noise ratio were calculated. Statistical analyses included descriptive statistics, t-tests, multivariate regression models, and partial Spearman correlations. RESULTS Scan times varied between 2:24 (T2-w, 11 SESs) and 8:49 minutes (STIR, 27 SESs). Reconstruction times varied between 3:14 minutes (T1-w, 11 SESs, 5 iterations) and 85:00 minutes (T2-w, 27 SESs, 50 iterations). Signal-to-noise ratio and contrast-to-noise ratio increased with increasing SESs, iterations, and normalization factor. In phantom scans, artifact reduction was optimal with an intermediate normalization factor (0.001) and improved with higher SESs and iterations. However, iterations greater than 20 did not improve artifact reduction or image quality further. On the contrary, ripple artifacts increased with higher SESs and iterations. In clinical scans, up to 20 iterations reduced blurring of the image; no further reduction was observed with iterations greater than 20. A normalization factor of 0.001 or 0.002 was best for reduction of blurring, whereas the soft tissue contrast was better and the distortion of soft tissue was less severe with lower normalization factors. Overall best soft tissue image quality was found for STIR and T1-w images with 19 SESs, 10 iterations, and a normalization factor of 0.001, and for T2-w images with 11 SESs, 10 iterations, and a normalization factor of 0.0005. CONCLUSIONS Optimized advanced acceleration and reconstruction algorithms of CS-SEMAC have been identified to reduce metal artifacts in patients with THA enabling imaging with clinically feasible acquisition and reconstruction times

Long Term Outcomes from CT-guided Indirect Cervical Nerve Root Blocks and their relationship to the MRI findings- A prospective Study

Purpose: To investigate long-term pain reduction and ‘improvement' in patients with indirect cervical nerve-root-blocks in comparison to MRI findings. Material and Methods: One hundred and twelve patients with MRI confirmed cervical radiculopathy and an indirect cervical nerve-root-block were included. Two radiologists independently evaluated the MRI examinations. 12 different MRI abnormalities at the level and side of infiltration were compared to pain relief and ‘improvement' at 1-month, 3-months and 1-year post injection. Results: The proportion of patients reporting clinically relevant 'improvement' was 36.7% at 1-month, 53.9% at 3-months and 68.1% at 1-year. At 1-month post injection, a statistically significantly lower percentage of patients eventually requiring surgery reported improvement and lower NRS change scores compared to those who did not undergo surgery (p = 0.001). Patients with extrusion of the disc were around 4-times more likely to have surgery. At 1-year post-injection the presence of nerve-root compromise was significantly linked to treatment outcome (p = 0.011). Conclusion: Patients with nerve root compression were more likely to report improvement at 1year. Patients with disc extrusions have less pain relief and are 4 times more likely to go to surgery than patients with disc protrusions. Key Points : • Good long term outcomes after indirect nerve root infiltrations with non-particulate steroids. • The presence of nerve root compression was a predictive finding of ‘improvement'. • Significantly less patients subsequently having surgery had lower NRS scores 1-month post injection. • There is less pain relief in patients with disc extrusions. • There are less improvement in patients with modic type I changes

Long Term Outcomes from CT-guided Indirect Cervical Nerve Root Blocks and their relationship to the MRI findings--A prospective Study

PURPOSE To investigate long-term pain reduction and 'improvement' in patients with indirect cervical nerve-root-blocks in comparison to MRI findings. MATERIAL AND METHODS One hundred and twelve patients with MRI confirmed cervical radiculopathy and an indirect cervical nerve-root-block were included. Two radiologists independently evaluated the MRI examinations. 12 different MRI abnormalities at the level and side of infiltration were compared to pain relief and 'improvement' at 1-month, 3-months and 1-year post injection. RESULTS The proportion of patients reporting clinically relevant 'improvement' was 36.7% at 1-month, 53.9% at 3-months and 68.1% at 1-year. At 1-month post injection, a statistically significantly lower percentage of patients eventually requiring surgery reported improvement and lower NRS change scores compared to those who did not undergo surgery (p = 0.001). Patients with extrusion of the disc were around 4-times more likely to have surgery. At 1-year post-injection the presence of nerve-root compromise was significantly linked to treatment outcome (p = 0.011). CONCLUSION Patients with nerve root compression were more likely to report improvement at 1 year. Patients with disc extrusions have less pain relief and are 4 times more likely to go to surgery than patients with disc protrusions. KEY POINTS • Good long term outcomes after indirect nerve root infiltrations with non-particulate steroids. • The presence of nerve root compression was a predictive finding of 'improvement'. • Significantly less patients subsequently having surgery had lower NRS scores 1-month post injection. • There is less pain relief in patients with disc extrusions. • There are less improvement in patients with modic type I changes

Osseous spurs at the fovea capitis femoris-a frequent finding in asymptomatic volunteers

OBJECTIVE To investigate the different morphologic types of the fovea capitis femoris and the spectrum of osseous spurs/osteophytes of the fovea in asymptomatic volunteers and patients with hip osteoarthritis. MATERIAL AND METHODS Sixty-five patients (mean age 63.6 years) with radiographically confirmed osteoarthritis of the hip and 59 asymptomatic healthy volunteers (mean age 33.9 years) underwent non-contrast MRI of the hip joint. Two radiologists independently evaluated all images. Fovea morphology (standard type, diamond type, flat type, triangular type) as well as the frequency, size and location of spurs/osteophytes of the fovea were assessed. Descriptive and inferential statistics were applied. RESULTS The most frequent morphologic type of the fovea capitis femoris was the standard type for both asymptomatic volunteers (average 45%) and patients (average 49%). Osseous spurs were detected in 70% of the asymptomatic volunteers, and 97% of the patients had osteophytes. Spur size at all locations was significantly smaller in asymptomatic volunteers (range 1-2 mm) than osteophyte size in patients (range 1-4 mm) (p ≤ 0.035). In volunteers and patients, the spurs/osteophytes were most frequently located at the anterior border of the fovea capitis femoris. CONCLUSION Smaller osseous spurs (<2 mm) at the border of the fovea capitis femoris are very common in asymptomatic volunteers and do not seem to be pathologic

Fluoroscopy-guided versus CT-guided Lumbar Steroid Injections: Comparison of Radiation Exposure and Outcomes

Purpose To compare the radiation exposure for participants and interventionalists as well as participant outcomes between fluoroscopy-guided versus CT-guided lumbar spinal injections. Materials and Methods This prospective, nonrandomized observational study included 1446 participants (mean age, 60.6 years; range, 18-91 years) who received transforaminal epidural injections or facet joint injections under fluoroscopic or CT guidance between October 2009 and April 2016. Effective doses were estimated by conversion from dose-area product for fluoroscopy-guided injections and dose-length product for CT-guided injections. Radiation exposure for interventionalists was measured with dosimeters at the body and wrist. The Patient Global Impression of Change (PGIC) scale was used to assess clinical participant outcomes at 1 day, 1 week, and 1 month after lumbar spine injections. Student t and χ tests were used for statistical analysis. Results The mean effective participant dose for fluoroscopy-guided lumbar transforaminal epidural injections was 0.24 mSv ± 0.22, compared with 0.33 mSv ± 0.10 for CT-guided injections (P < .003). The mean effective participant dose for fluoroscopy-guided lumbar facet joint injections was 0.10 mSv ± 0.11, compared with 0.33 mSv ± 0.13 for CT-guided injections (P < .001). Radiation exposure for the interventionalist was higher during fluoroscopy-guided compared with CT-guided lumbar transforaminal epidural injections (body: 0.42 × 10 mSv ± 0.99 vs 0.11 × 10 mSv ± 0.44, P < .03; wrist: 1.44 × 10 mSv ± 2.69 vs 0.14 × 10 mSv ± 0.55, P < .001). Radiation exposure of the wrist for the interventionalist was higher during fluoroscopy-guided compared with CT-guided lumbar facet injections (0.46 × 10 mSv ± 0.93 vs 0.06 × 10 mSv ± 0.24, respectively; P < .006). Clinical participant outcomes as determined with the PGIC scale did not differ between fluoroscopy-guided and CT-guided injections (P = .15-.96). Conclusion Radiation exposure in fluoroscopy-guided lumbar spinal injections was lower for participants and higher for physicians when compared with CT-guided injections; however, no associations were observed between clinical participant outcomes and type of imaging-guided injection technique at all evaluated time points

Is there a difference in treatment outcomes between epidural injections with particulate versus non-particulate steroids?

OBJECTIVES To compare the outcomes of patients after interlaminar computed tomography (CT)-guided epidural injections of the lumbar spine with particulate vs. non-particulate steroids. METHODS 531 consecutive patients were treated with CT-guided lumbar interlaminar epidural injections with steroids and local anaesthetics. 411 patients received a particulate steroid and 120 patients received a non-particulate steroid. Pain levels were assessed using the 11-point numerical rating scale (NRS) and overall reported 'improvement' was assessed using the Patients Global Impression of Change (PGIC) at 1 day, 1 week and 1 month post-injection. Descriptive and inferential statistics were applied. RESULTS Patients receiving particulate steroids had statistically significantly higher NRS change scores (p = 0.0001 at 1 week; p = 0.0001 at 1 month). A significantly higher proportion of patients receiving particulate steroids reported relevant improvement (PGIC) at both 1 week and 1 month post injection (p = 0.0001) and they were significantly less likely to report worsening at 1 week (p = 0.0001) and 1 month (p = 0.017). CONCLUSION Patients treated with particulate steroids had significantly greater pain relief and were much more likely to report clinically relevant overall 'improvement' at 1 week and 1 month compared to the patients treated with non-particulate steroids. KEY POINTS • CT-guided epidural injections of the lumbar spine with particulate vs. non-particulate steroids. • Good outcomes with particulate steroids. • Less pain relief in patients with non-particulate steroids. • Less improvement in patients with non-particulate steroids

Particulate versus non-particulate corticosteroids for transforaminal nerve root blocks: Comparison of outcomes in 494 patients with lumbar radiculopathy

PURPOSE We set out to compare outcomes in CT-guided lumbar transforaminal nerve root block patients receiving either particulate or non-particulate corticosteroids. MATERIALS AND METHODS This was a retrospective comparative effectiveness outcomes study on two cohorts of lumbar radiculopathy patients. 321 received particulate and 173 non-particulate corticosteroids at CT-guided transforaminal lumbar nerve root injections. The particulate steroid was used from October 2009 until May 2014 and the non-particulate steroid was used from May 2014. Pain levels were collected at baseline using an 11-point numerical rating scale (NRS) and at 1 day, 1 week and 1 month. Overall 'improvement' was assessed using the Patients' Global Impression of Change (PGIC) at these same time points (primary outcome). The proportions of patients 'improved' were compared between the two groups using the Chi-square test. The NRS change scores were compared using the unpaired t-test. RESULTS A significantly higher proportion of patients treated with particulate steroids were improved at 1 week (43.2 % vs. 27.7 %, p = 0.001) and at 1 month (44.3 % vs. 33.1 %, p = 0.019). Patients receiving particulate steroids also had significantly higher NRS change scores at 1 week (p = 0.02) and 1 month (p = 0.007). CONCLUSION Particulate corticosteroids have significantly better outcomes than non-particulate corticosteroids. KEY POINTS • Better pain relief is achieved with particulate steroids. • Significantly more patients report overall 'improvement' with particulate steroids. • Significantly more patients report 'worsening' at 1 week with non-particulate steroids

Structural and Functional Results of Subscapularis and Conjoint Tendon After Latarjet Procedure at 8-Year Average Follow-up

BACKGROUND The Latarjet procedure involves initial dissection through a longitudinal split of the subscapularis tendon with only a final partial closure to accommodate the transferred coracoid bone. Furthermore, by transferring the coracoid bone block to the anterior glenoid, the surgeon completely alters the resting and dynamic route of the attached conjoint tendon. The eventual structural and functional integrity of the subscapularis and conjoint tendons is currently unknown. PURPOSE To examine the structural and functional integrity of the subscapularis and the conjoint tendon after the Latarjet procedure at an 8-year average follow-up. STUDY DESIGN Case series; Level of evidence, 4. METHODS Twenty patients with anterior shoulder instability at a mean age of 30 years (range, 19-50 years) underwent the open Latarjet procedure. Clinical examination at the final follow-up included quantitative isometric measurement of abduction and internal rotation strength compared with the nonoperative side. Patients were assessed via radiograph examination and preoperative computed tomography. Final position and healing of the transferred coracoid bone block were evaluated using standard radiographs. At follow-up, the subscapularis and conjoint tendon were evaluated via magnetic resonance imaging (MRI) with metal artifact reduction techniques and via ultrasound. RESULTS Nineteen of the 20 shoulders remained stable at the final follow-up; there was 1 redislocation (5%) after 14 months. The mean Rowe score was 83 points (SD, 17.9 points), the mean Constant score was 85 points (SD, 8.1 points), and the Subjective Shoulder Value was 80% (SD, 18%). The mean abduction strength of the operative shoulder was 7.41 ± 2.06 kg compared with 8.33 ± 2.53 kg for the nonoperative side (P = .02). The mean internal rotation strength at 0° for the operative shoulder was 8.82 ± 3.47 kg compared with 9.06 ± 3.01 kg for the nonoperative side (P = .36). The mean internal rotation strength in the belly-press position for the operative shoulder was 8.12 ± 2.89 kg compared with 8.50 ± 3.03 kg (P = .13). Four of 20 shoulders showed mild tendinopathic changes of the subscapularis tendon but no partial or complete tear. One patient exhibited fatty degeneration Goutallier stage 1. Conjoint tendon was in continuity in all 20 shoulders on MRI scans. CONCLUSION Abduction, but not internal rotation strength, was slightly reduced after the Latarjet procedure at a mean of 8 years of follow-up. The subscapularis tendon was intact based on ultrasound examination, and the conjoint tendon was intact based on MRI scans. Subscapularis muscle girth relative to the supraspinatus muscle remained intact from preoperative measurements based on MRI scans

CAIPIRINHA-accelerated 10-min 3D TSE MRI of the ankle for the diagnosis of painful ankle conditions: Performance evaluation in 70 patients

OBJECTIVES To test the hypothesis that MRI of the ankle with a 10-min 3D CAIPIRINHA SPACE TSE protocol is at least equivalent for the detection of painful conditions when compared to a 20-min 2D TSE standard of reference protocol. METHODS Following institutional review board approval and informed consent, 70 symptomatic subjects underwent 3T MRI of the ankle. Six axial, sagittal and coronal intermediate-weighted (IW) and fat-saturated T2-weighted (T2FS) 2D TSE (total acquisition time, 20 min), and two sagittal isotropic IW and T2FS 3D CAIPIRINHA TSE (10 min) pulse sequence prototypes were obtained. Following randomization and anonymization, two musculoskeletal radiologists evaluated the 2D and 3D datasets independently. Descriptive statistics, inter-reader reliability, inter-method concordance, diagnostic definitiveness tests were applied. P-values < 0.05 were considered significant. RESULTS Raters diagnosed 116 cartilage defects with 2D and 109 with 3D MRI, 35 ligament tears with 2D and 65 with 3D MRI, 18 tendon tears with 2D and 20 with 3D MRI, and 137 osseous abnormalities with 2D and 149 with 3D MRI. The inter-reader agreement was high for 2D (Kendall W, 0.925) and 3D MRI (W, 0.936) (p < 0.05), as was the inter-method concordance (W, 0.919). The diagnostic definitiveness of readers was higher for 3D MRI than 2D MRI in 10-27% of the time, while the reverse was true in 7-11% of the time (p < 0.01). CONCLUSIONS The performance of 10-min 3D CAIPIRINHA SPACE MRI for the detection of painful ankle conditions is similar to that of a 20-min 2D TSE MRI reference standard. KEY POINTS • CAIPIRINHA Acceleration facilitates isotropic 3D MRI of the Ankle in 10 min. • 10-min 3D CAIPIRINHA MRI and 20-min 2D TSE MRI have similar performance. • 3D CAIPIRINHA SPACE MRI afforded higher diagnostic definitiveness of readers