Value of MR arthrography for evaluation of children and adolescents with clinically suspected intraarticular cause of hip pain

PURPOSE

To evaluate the distribution of intra- and extraarticular MRI findings in children and adolescents with clinically suspected intraarticular cause of hip pain in order to assess the need for additional intraarticular contrast administration.

MATERIAL AND METHODS

Database was searched over a period of 34 months retrospectively for consecutive hip MR arthrography in young patients (8-17 years) with suspected intraarticular cause of hip or groin pain. Exclusion criteria were prior hip surgery, follow-up examination due to known intraarticular pathology, incomplete examination, qualitatively non-diagnostic examinations, and missing informed consent. Reports of fellowship-trained MSK radiologists were searched for intraarticular versus extraarticular findings explaining hip or groin pain.

RESULTS

Seventy patients (68% female; median age: 14.5 years; range:10.8-16.9 years) were analyzed. No reason for pain was found in 30 (42.9%) hips, extraarticular reasons in 20 (28.6%) cases, intraarticular in 14 (20.0%), and both (intra- and extraarticular) in 6 (8.6%) hips. Most common extraarticular reasons were apophysitis (14.3%), other bony stress reactions (12.9%), intramuscular edema (7%), tendinitis (5.7%), and trochanteric bursitis (4.3%). Labral pathology was the most common intraarticular finding (overall:34.3%; partial tear:15.7%, complete tear:15.7%), most frequent at the anterosuperior position (81.8%). Cartilage defects (1.4%), intraarticular neoplasia (1.4%), and tear of the femoral head ligament (2.8%) were rarely found. Synovitis and loose bodies were not observed. Cam-(37.1%) and pincer-configurations (47.1%) were common while hip dysplasia was rare (5.7%).

CONCLUSION

MRI in children and adolescents with hip pain should be done primarily without intraarticular contrast administration since most cases show an extraarticular pain reason or no diagnosis detectable with MRI.

Mid-term results of autologous matrix-induced chondrogenesis for large chondral defects in hips with femoroacetabular impingement syndrome

Aims

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

Methods

This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm2, who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain.

Results

A total of 12 hips from 11 patients were included (ten males, one female, mean age 26.8 years (SD 5.0), mean follow-up 6.2 years (SD 5.2 months)). The mean postoperative MOCART score was 66.3 (SD 16.3). None of the patients required conversion to total hip arthroplasty. Two patients had anterior impingement. External hip rotation was moderately limited in four patients. There was a correlation between MOCART and follow-up time (rs = -0.61; p = 0.035), but not with initial cartilage damage, age, BMI, or imaging time delay before surgery. PROMs improved significantly: OHS from 37.4 to 42.7 (p = 0.014) and COMI from 4.1 to 1.6 (p = 0.025). There was no correlation between MOCART and PROMs.

Conclusion

Based on the reported mid-term results, we consider AMIC as an encouraging treatment option for large cartilage lesions of the hip. Nonetheless, the clinical evidence of AMIC in FAI patients remains to be determined, ideally in the context of randomized controlled trials.

Morphological and Quantitative Parametric MRI Follow-up of Cartilage Changes Before and After Intra-articular Injection Therapy in Patients With Mild to Moderate Knee Osteoarthritis: A Randomized, Placebo-Controlled Trial

BACKGROUND

Intra-articular injections are routinely used for conservative treatment of knee osteoarthritis (OA). The detailed comparative therapeutic effects of these injections on cartilage tissue are still unclear.

OBJECTIVE

The aim of this study was to detect and compare knee cartilage changes after intra-articular injection of glucocorticoid, hyaluronic acid, or platelet-rich plasma (PRP) to placebo using quantitative (T2 and T2* mapping) and morphological magnetic resonance imaging parameters in patients with mild or moderate osteoarthritis.

MATERIALS AND METHODS

In a double-blinded, placebo-controlled, single-center trial, knees with mild or moderate osteoarthritis (Kellgren-Lawrence grade 1-3) were randomly assigned to an intra-articular injection with 1 of these substances: glucocorticoid, hyaluronic acid, PRP, or placebo. Cartilage degeneration on baseline and follow-up magnetic resonance imaging scans (after 3 and 12 months) was assessed by 2 readers using quantitative T2 and T2* times (milliseconds) and morphological parameters (modified Outerbridge grading, subchondral bone marrow edema, subchondral cysts, osteophytes).

RESULTS

One hundred twenty knees (30 knees per treatment group) were analyzed with a median patient age of 60 years (interquartile range, 54.0-68.0 years). Interreader reliability was good for T2 (ICC, 0.76; IQR, 0.68-0.83) and T2* (ICC, 0.83; IQR, 0.76-0.88) measurements. Morphological parameters showed no significant changes between all groups after 3 and 12 months. T2 mapping after 12 months showed the following significant ( P = 0.001-0.03) changes between groups in 6 of 14 compartments: values after PRP injection decreased compared with glucocorticoid in 4 compartments (complete medial femoral condyle and central part of lateral condyle) and compared with placebo in 2 compartments (anterior and central part of medial tibial plateau); values after glucocorticoid injection decreased compared with placebo in 1 compartment (central part of medial tibial plateau). No significant changes were seen for T2 and T2* times after 3 months and T2* times after 12 months. No correlation was found between T2/T2* times and Kellgren-Lawrence grade, age, body mass index, or pain (Spearman ρ, -0.23 to 0.18).

CONCLUSIONS

Platelet-rich plasma injection has a positive long-term effect on cartilage quality in the medial femoral compartment compared to glucocorticoid, resulting in significantly improved T2 values after 12 months. For morphological cartilage parameters, injections with glucocorticoid, PRP, or hyaluronic acid showed no better effect in the short or long term compared with placebo.

Muscle atrophy in diabetic patients with Charcot foot: a case-control study

PURPOSE

To evaluate the distribution and severity of muscle atrophy in diabetic patients with active Charcot foot (CF) compared to diabetic patients without CF. Furthermore, to correlate the muscle atrophy with severity of CF disease.

MATERIAL/METHODS

In this retrospective study, MR images of 35 diabetic patients (21 male, median:62.1 years ± 9.9SD) with active CF were compared with an age- and gender-matched control group of diabetic patients without CF. Two readers evaluated fatty muscle infiltration (Goutallier-classification) in the mid- and hindfoot. Furthermore, muscle trophic (cross-sectional muscle area (CSA)), intramuscular edema (none/mild versus moderate/severe), and the severity of CF disease (Balgrist Score) were assessed.

RESULTS

Interreader correlation for fatty infiltration was substantial to almost perfect (kappa-values:0.73-1.0). Frequency of fatty muscle infiltration was high in both groups (CF:97.1-100%; control:77.1-91.4%), but severe infiltration was significantly more frequent in CF patients (p-values: < 0.001-0.043). Muscle edema was also frequently seen in both groups, but significantly more often in the CF group (p-values: < 0.001-0.003). CSAs of hindfoot muscles were significantly smaller in the CF group. For the flexor digitorum brevis muscle, a cutoff value of 139 mm2 (sensitivity:62.9%; specificity:82.9%) in the hindfoot was found to differentiate between CF disease and the control group. No correlation was seen between fatty muscle infiltration and the Balgrist Score.

CONCLUSION

Muscle atrophy and muscle edema are significantly more severe in diabetic patients with CF disease. Muscle atrophy does not correlate with the severity of active CF disease. A CSA < 139 mm2 of the flexor digitorum brevis muscle in the hindfoot may indicate CF disease.

Three-dimensional analysis for quantification of knee joint space width with weight-bearing CT: comparison with non-weight-bearing CT and weight-bearing radiography

OBJECTIVE

To compare computer-based 3D-analysis for quantification of the femorotibial joint space width (JSW) using weight-bearing cone beam CT (WB-CT), non-weight-bearing multi-detector CT (NWB-CT), and weight-bearing conventional radiographs (WB-XR).

DESIGN

Twenty-six participants prospectively underwent NWB-CT, WB-CT, and WB-XR of the knee. For WB-CT and NWB-CT, the average and minimal JSW was quantified by 3D-analysis of the minimal distance of any point of the subchondral tibial bone surface and the femur. Associations with mechanical leg axes and osteoarthritis were evaluated. Minimal JSW of WB-CT was further compared to WB-XR. Two-tailed p-values of <0.05 were considered significant.

RESULTS

Significant differences existed of the average medial and lateral JSW between WB-CT and NWB-CT (medial: 4.7 vs 5.1 mm [P = 0.028], lateral: 6.3 vs 6.8 mm [P = 0.008]). The minimal JSW on WB-XR (medial:3.1 mm, lateral:5.8 mm) were significantly wider compared to WB-CT and NWB-CT (both medial:1.8 mm, lateral:2.9 mm, all p < 0.001), but not significantly different between WB-CT and NWB-CT (all p ≥ 0.869). Significant differences between WB-CT and NWB-CT existed in participants with varus knee alignment for the average and the minimal medial JSW (p = 0.004 and p = 0.011) and for participants with valgus alignment for the average lateral JSW (p = 0.013). On WB-CT, 25% of the femorotibial compartments showed bone-on-bone apposition, which was significantly higher when compared to NWB-CT (10%,P = 0.008) and WB-XR (8%,P = 0.012).

CONCLUSION

Combining WB-CT with 3D-based assessment allows detailed quantification of the femorotibial joint space and the effect of knee alignment on JSW. WB-CT demonstrates significantly more bone-on-bone appositions, which are underestimated or even undetectable on NWB-CT and WB-XR.

Ligaments of the scapho-trapezial-trapezoidal joint: MR anatomy in asymptomatic and symptomatic individuals

PURPOSE

To evaluate the MRI anatomy of the scapho-trapezial-trapezoidal (STT) ligament complex in asymptomatic and symptomatic individuals.

MATERIAL AND METHODS

In this retrospective study, STT ligament complex of 42 (male 69%, median age 37.5 years) asymptomatic (n = 25) and symptomatic (n = 17) (defined as pain described over the STT joint) individuals was examined using a high-resolution 3D proton density-weighted isovoxel sequence (MR arthrogram) with multiplanar reconstructions. Two musculoskeletal radiologists independently assessed visibility, signal intensity (SI), morphology, and thickness of the radiopalmar scapho-trapezial ligament (rpSTL), palmar scapho-capitate capsular ligament (pSCL), palmar STT capsule (pSTTC), and dorsal STT capsule (dSTTC).

RESULTS

Interreader agreement ranged from fair to good and intraclass correlations were good. The rpSTL was almost always visible (85.7%/80.1%; reader 1/reader 2). The pSCL and dSTTC were visible in all cases. The pSTTC was visible in only 52.4%/42.9%. Mean thickness of the rpSTL, pSCL, pSTTC, and dSTTC was 1.4 ± 0.5 mm/1.3 ± 0.5 mm, 2.8 ± 0.7 mm/2.7 ± 0.6 mm, 0.5 ± 0.5 mm/0.4 ± 0.4 mm, and 0.5 ± 0.3 mm/0.3 ± 0.3 mm. Both readers rated SI of the rpSTL significantly more often as increased in the symptomatic group (increased SI in asymptomatic group: 20%/15%; symptomatic group: 56%/50%) (p-values < 0.005). For all other ligaments, no significant difference was observed for SI between symptomatic and asymptomatic group (p-values ranging between 0.188 and 0.890). For all other ligaments, no significant differences were observed regarding ligament visibility, morphology, and thickness (p-values ranging between 0.274 and 1.000).

CONCLUSION

The anatomy of the STT ligament complex can consistently be visualized on high-resolution 3D MRI. Increased signal intensity of rpSTL is significantly more frequent in patients with radial-sided wrist pain.

Pelvic bone CT: can tin-filtered ultra-low-dose CT and virtual radiographs be used as alternative for standard CT and digital radiographs?

Objectives

To compare ultra-low-dose CT (ULD-CT) of the osseous pelvis with tin filtration to standard clinical CT (CT), and to assess the quality of computed virtual pelvic radiographs (VRs).

Methods

CT protocols were optimized in a phantom and three pelvic cadavers. Thirty prospectively included patients received both standard CT (automated tube voltage selection and current modulation) and tin-filtered ULD-CT of the pelvis (Sn140kV/50mAs). VRs of ULD-CT data were computed using an adapted cone beam–based projection algorithm and were compared to digital radiographs (DRs) of the pelvis. CT and DR dose parameters and quantitative and qualitative measures (1 = worst, 4 = best) were compared. CT and ULD-CT were assessed for osseous pathologies.

Results

Dose reduction of ULD-CT was 84% compared to CT, with a median effective dose of 0.38 mSv (quartile 1–3: 0.37–0.4 mSv) versus 2.31 mSv (1.82–3.58 mSv; p < .001), respectively. Mean dose of DR was 0.37 mSv (± 0.14 mSv). The median signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of bone were significantly higher for CT (64.3 and 21.5, respectively) compared to ULD-CT (50.4 and 18.8; p ≤ .01), while ULD-CT was significantly more dose efficient (figure of merit (FOM) 927.6) than CT (FOM 167.6; p < .001). Both CT and ULD-CT were of good image quality with excellent depiction of anatomy, with a median score of 4 (4–4) for both methods (p = .1). Agreement was perfect between both methods regarding the prevalence of assessed osseous pathologies (p > .99). VRs were successfully calculated and were equivalent to DRs.

Conclusion

Tin-filtered ULD-CT of the pelvis at a dose equivalent to standard radiographs is adequate for assessing bone anatomy and osseous pathologies and had a markedly superior dose efficiency than standard CT.

Key Points

• Ultra-low-dose pelvic CT with tin filtration (0.38 mSv) can be performed at a dose of digital radiographs (0.37 mSv), with a dose reduction of 84% compared to standard CT (2.31 mSv).

• Tin-filtered ultra-low-dose CT had lower SNR and CNR and higher image noise than standard CT, but showed clear depiction of anatomy and accurate detection of osseous pathologies.

• Virtual pelvic radiographs were successfully calculated from ultra-low-dose CT data and were equivalent to digital radiographs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07824-x.

Influence of pregnancy/childbirth on long-term bone marrow edema and subchondral sclerosis of sacroiliac joints

OBJECTIVE

To investigate long-term effects of pregnancy/childbirth on bone marrow edema (BME) and subchondral sclerosis of sacroiliac joints (SIJ) in comparison to MRI changes caused by spondyloarthritis (SpA) and assess the influence of birth method and number of children on SIJ-MRI changes.

MATERIALS AND METHODS

This is a retrospective cohort study with 349 women (mean age 47 ± 14 years) suffering low back pain. Four subgroups were formed based on SpA diagnosis and childbirth (CB) history. Two musculoskeletal radiologists scored the presence of BME and sclerosis on SIJ-MRI using the Berlin method. Further, an 11-point "global assessment score" representing the overall confidence of SpA diagnosis based on MRI was evaluated in addition to the ASAS (Assessment of Spondyloarthritis International Society) criterion of "positive MRI" for sacroiliitis.

RESULTS

CB did not correlate with BME score (p = 0.38), whereas SpA diagnosis was associated with a higher BME score (r = 0.31, p < 0.001). Both CB (r = 0.21, p < 0.001) and SpA diagnosis (r = 0.33, p < 0.001) were correlated with a higher sclerosis score. CB was not associated with a higher confidence level in diagnosing SpA based on MRI (p = 0.07), whereas SpA diagnosis was associated with a higher score (r = 0.61, p < 0.001). Both CB (phi = 0.13, p = 0.02) and SpA diagnosis (phi = 0.23, p < 0.001) were significantly associated with a positive ASAS criterion for sacroiliitis. In non-SpA patients with CB, number of children (p = 0.001) was an independent predictor of sclerosis score, while birth method yielded no significant effect (p = 0.75).

CONCLUSION

Pregnancy/CB has no impact on long-term BME on SIJ, however, may cause long-term subchondral sclerosis-similar to SpA-associated sclerosis. Number of children is positively correlated with SIJ sclerosis. Birth method yields no effect on SIJ sclerosis.

The "Balgrist Score" for evaluation of Charcot foot: a predictive value for duration of off-loading treatment

OBJECTIVE

To develop a new magnetic resonance imaging(MRI) scoring system for evaluation of active Charcot foot and to correlate the score with a duration of off-loading treatment ≥ 90 days.

METHODS

An outpatient clinic database was searched retrospectively for MRIs of patients with active Charcot foot who completed off-loading treatment. Images were assessed by two radiologists (readers 1 and 2) and an orthopedic surgeon (reader 3). Sanders/Frykberg regions I-V were evaluated for soft tissue edema, bone marrow edema, erosions, subchondral cysts, joint destruction, fractures, and overall regional manifestation using a score according to degree of severity (0-3 points). Intraclass correlations (ICC) for interreader agreement and receiver operating characteristic analysis between MR findings and duration of off-loading-treatment were calculated.

RESULTS

Sixty-five feet in 56 patients (34 men) with a mean age of 62.4 years (range: 44.5-85.5) were included. Region III (reader 1/reader 2: 93.6/90.8%) and region II (92.3/90.8%) were most affected. The most common findings in all regions were soft tissue edema and bone marrow edema. Mean time between MRI and cessation of off-loading-treatment was 150 days (range: 21-405). The Balgrist Score was defined in regions II and III using soft tissue edema, bone marrow edema, joint destruction, and fracture. Interreader agreement for Balgrist Score was excellent: readers 1/2: ICC 0.968 (95% CI: 0.948, 0.980); readers 1/2/3: ICC 0.856 (0.742, 0.917). A cutoff of ≥ 9.0 points in Balgrist Score (specificity 72%, sensitivity 66%) indicated a duration of off-loading treatment ≥ 90 days.

CONCLUSION

The Balgrist Score is a new MR scoring system for assessment of active Charcot foot with excellent interreader agreement. The Balgrist Score can help to identify patients with off-loading treatment ≥ 90 days.

Diagnosis of Periprosthetic Hip Joint Infection Using MRI with Metal Artifact Reduction at 1.5 T

Background MRI with metal artifact reduction has gained importance in assessment of pain with total hip arthroplasty (THA). However, its role in diagnosis of periprosthetic joint infection (PJI) has not been well defined. Purpose To evaluate findings of PJI after THA and to determine the diagnostic performance of 1.5-T MRI with metal artifact reduction. Materials and Methods Dedicated compressed sensing-based slice encoding for metal artifact correction 1.5-T MRI examinations (from January 2015 to April 2018) in patients with THA PJI (infection group) and noninfected THA (control group) were retrospectively evaluated by two musculoskeletal radiologists. Fisher exact test was used to compare the groups. Sensitivity, specificity, and accuracy were evaluated for each finding. Interobserver reliability was assessed with κ statistics. Results Forty patients (mean age, 69 years ± 11 [standard deviation]; 26 men) in the infection group and 100 patients (mean age, 67 years ± 11; 42 men) in the control group were evaluated. Periosteal reaction, capsule edema, and intramuscular edema differed between the two groups (P < .001 for each finding). Periosteal reaction was found in 31 of 40 patients with infection and 10 of 100 participants in the control group (sensitivity, 78%; specificity, 90%; accuracy, 86%); capsule edema was found in 33 of 40 (infection group) and five of 100 (control group) (sensitivity, 83%; specificity, 95%; accuracy, 91%); and intramuscular edema was found in 38 of 40 (infection group) and 14 of 100 (control group) (sensitivity, 95%; specificity, 86%; accuracy, 89%). Interobserver agreement was almost perfect, with κ values between 0.88 and 0.92. No difference between the two groups was found regarding the presence of osteolysis (infection group, 23 of 40; control group, 60 of 100), bone marrow edema (39 of 40 vs 87 of 100), effusion (20 of 40 vs 26 of 100), abductor tendon lesion (22 of 40 vs 62 of 100), or bursitis (14 of 40 vs 34 of 100) (P > .05 for each finding). Conclusion The presence of periosteal reaction, capsule edema, and intramuscular edema after total hip arthroplasty at 1.5-T MRI with metal artifact reduction had a high accuracy in evaluation of periprosthetic joint infection. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Zanetti in this issue.

Ultrasound-guided interventions with augmented reality in situ visualisation: a proof-of-mechanism phantom study

Background

Ultrasound (US) images are currently displayed on monitors, and their understanding needs good orientation skills. Direct overlay of US images onto the according anatomy is possible with augmented reality (AR) technologies. Our purpose was to explore the performance of US-guided needle placement with and without AR in situ US viewing.

Methods

Three untrained operators and two experienced radiologists performed 200 US-guided punctures: 100 with and 100 without AR in situ US. The punctures were performed in two different phantoms, a leg phantom with soft tissue lesions and a vessel phantom. Time to puncture and number of needle passes were recorded for each puncture. Data are reported as median [range] according to their non-normal distribution.

Results

AR in situ US resulted in reduced time (median [range], 13 s [3–101] versus 14 s [3–220]) and number of needle passes (median [range], 1 [1–4] versus 1 [1–8]) compared to the conventional technique. The initial gap in performance of untrained versus experienced operators with the conventional US (time, 21.5 s [3–220] versus 10.5 s [3–94] and needle passes 1 [1–8] versus 1 [1, 2]) was reduced to 12.5 s [3–101] versus 13 s [3–100] and 1 [1–4] versus 1 [1–4] when using AR in situ US, respectively.

Conclusion

AR in situ US could be a potential breakthrough in US applications by simplifying operator’s spatial orientation and reducing experience-based differences in performance of US-guided interventions. Further studies are needed to confirm these preliminary phantom results.

Impact of stem design and cementation on postoperative femoral antetorsion in 227 patients with total hip arthroplasty (THA)

OBJECTIVE

In total hip arthroplasty (THA), surgeons attempt to achieve a physiological antetorsion. However, postoperative antetorsion of the femoral stem is known to show large variabilities. The purpose of this study was to assess whether postoperative antetorsion is influenced by stem design or cementation.

MATERIALS AND METHODS

This retrospective study included 227 patients with a hip prosthesis with five different stem designs (S1: short curved, S2 and S3: standard straight, S4: standard straight collared, S5: cemented straight), who had metal suppressed 1.5T-MRI of the hip between February 2015 and October 2019. Measurement of femoral antetorsion was done independently by two fellowship-trained radiologists on axial images by measuring the angle between the long axis of the femoral neck and the posterior condylar tangent of the knee. Measured angles in the different groups were compared using the t test for independent samples.

RESULTS

The cementless collared stem S4 showed the highest antetorsion with 18.1° (± 10.5°; range -10°-45°), which was significantly higher than the antetorsion of the collarless S3 with 13.3° (± 8.4°; - 4°-29°) and the cemented S5 with 12.7° (± 7.7°; - 3°-27°) with p = 0.012 and p = 0.007, respectively. S1 and S2 showed an antetorsion of 14.8° (± 10.0°; 1°-37°) and 14.1° (± 12.2°; - 20°-41°). The torsional variability of the cementless stems (S1-4) was significantly higher compared with that of the cemented S5 with a combined standard deviation of 10.5° and 7.7° (p = 0.019).

CONCLUSION

Prosthesis design impacts the postoperative femoral antetorsion, with the cementless collared stem showing the highest antetorsion. Cemented stems demonstrated significantly lower variability, suggesting the lowest rate of inadvertent malrotation.

MRI with state-of-the-art metal artifact reduction after total hip arthroplasty: periprosthetic findings in asymptomatic and symptomatic patients

OBJECTIVES

To assess the spectrum of periprosthetic MRI findings after primary total hip arthroplasty (THA).

METHODS

This multi-center cohort study analyzed 31 asymptomatic patients (65.7 ± 12.7 years) and 27 symptomatic patients (62.3 ± 11.9 years) between 6 months and 2 years after THA. 1.5-T MRI was performed using Compressed Sensing SEMAC and high-bandwidth sequences. Femoral stem and acetabular cup were assessed for bone marrow edema, osteolysis, and periosteal reaction in Gruen zones and DeLee and Charnley zones. Student t test and Fisher's exact test were performed.

RESULTS

The asymptomatic and symptomatic groups showed different patterns of imaging findings. Bone marrow edema was seen in 19/31 (61.3%) asymptomatic and 22/27 (81.5%) symptomatic patients, most commonly in Gruen zones 1, 7, and 8 (p ≥ 0.18). Osteolysis occurred in 14/31 (45.2%) asymptomatic and 14/27 (51.9%) symptomatic patients and was significantly more common in Gruen zone 7 in the symptomatic group (8/27 (29.6%)) compared to the asymptomatic group (2/31 (6.5%)) (p = 0.03). Periosteal reaction was present in 4/31 asymptomatic (12.9%) and 9/27 symptomatic patients (33.3%) and more common in Gruen zones 5 and 6 in the symptomatic group (p = 0.04 and 0.02, respectively). In the acetabulum, bone marrow edema pattern was encountered in 3/27 (11.1%) symptomatic patients but not in asymptomatic patients (p ≥ 0.21). Patient management was altered in 8/27 (29.6%) patients based on MRI findings.

CONCLUSIONS

Periprosthetic bone marrow edema is common after THA both in asymptomatic and symptomatic patients. Osteolysis and periosteal reaction are more frequent in symptomatic patients. MRI findings led to altered patient management in 29.6% of patients.

KEY POINTS

• Bone marrow edema pattern was frequent in both asymptomatic and symptomatic patients after THA, particularly around the proximal femoral stem in Gruen zones 1, 7, and 8. • Osteolysis was significantly more frequent in symptomatic patients in Gruen zone 7. • Periosteal reaction occurred more frequently in symptomatic patients in Gruen zones 5 and 6.

Acetabular coverage differs between standing and supine positions: model-based assessment of low-dose biplanar radiographs and comparison with CT

OBJECTIVES

To evaluate the feasibility of 2D and 3D acetabular coverage assessments based on low-dose biplanar radiographs (BPR) in comparison with CT, and to demonstrate the influence of weight-bearing position (WBP) on anterior and posterior acetabular coverages.

METHODS

Fifty patients (21 females, 29 males) underwent standing BPR and supine CT of the pelvis. Using dedicated software, BPR-based calculations of anterior and posterior 2D coverages and anterior, posterior, and global 3D coverages were performed in standardized anterior pelvic plane (APP) and WBP. CT-based anterior and posterior 2D coverages and global 3D coverage was calculated in APP and compared with BPR-based data. Statistics included intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Mean anterior 2D coverage was 21.2% (standard deviation, ± 7.4%) for BPR and 23.8% (± 8.4%) for CT (p = 0.226). Mean posterior 2D coverage was 54.2% (± 9.8%) for BPR and 61.7% (± 9.7%) for CT (p = 0.001). Mean global 3D coverage was 46.5% (± 3.0%) for BPR and 45.6% (± 3.6%) for CT (p = 0.215). The inter-method reliability between CT and BPR and inter-reader reliability for BPR-based measurements were very good for all measurement (all ICC > 0.8). Based on BPR, mean anterior and posterior 3D coverages were 20.5% and 26.0% in WBP and APP, while 25 patients increased anterior and 24 patients increased posterior 3D coverage from APP to WBP with a relative change of coverage of up to 11.9% and 10.0%, respectively.

CONCLUSIONS

2D and 3D acetabular coverages can be calculated with very good reliability based on BPR. The impact of standing position on acetabular coverage can be quantified with BPR on an individual basis.

KEY POINTS

• 2D and 3D acetabular coverages can be calculated with very good reliability based on biplanar radiographs in comparison with CT. • The impact of standing position on anterior and posterior acetabular coverages can be quantified with BPR on an individual basis.

The Charcot foot: a pictorial review

Charcot foot refers to an inflammatory pedal disease based on polyneuropathy; the detailed pathomechanism of the disease is still unclear. Since the most common cause of polyneuropathy in industrialized countries is diabetes mellitus, the prevalence in this risk group is very high, up to 35%. Patients with Charcot foot typically present in their fifties or sixties and most of them have had diabetes mellitus for at least 10 years. If left untreated, the disease leads to massive foot deformation. This review discusses the typical course of Charcot foot disease including radiographic and MR imaging findings for diagnosis, treatment, and detection of complications.

Pincer-type MRI morphology seen in over a third of asymptomatic healthy volunteers without femoroacetabular impingement

BACKGROUND

In daily routine, pincer femoroacetabular impingement (FAI) findings are often seen without a clinical diagnosis of pincer FAI.

PURPOSE

To assess the presence of pincer FAI MRI findings in asymptomatic volunteers with negative impingement test versus patients with clinically confirmed FAI.

STUDY TYPE

Case-control study.

POPULATION

Sixty-three asymptomatic volunteers and 63 matched patients with FAI were included.

FIELD STRENGTH/ SEQUENCE

A coronal T₁ -weighted turbo spin-echo sequence as well as a 3D oblique transverse water-excitation true fast imaging sequence at 1.5T.

ASSESSMENT

The volunteers underwent standard MRI of the hip, and patients underwent MR arthrography of the symptomatic hip using the same MR sequences. Measurements of cranial acetabular version, acetabular depth, and lateral center-edge angle were performed independently by three fellowship-trained musculoskeletal radiologists.

STATISTICAL TESTS

Descriptive statistics, Mann-Whitney U-test, Unpaired t-test, receiver operating characteristics (ROC), Intraclass correlation coefficient (ICC).

RESULTS

Forty-one percent (26/63, reader 1), 32% and 37% (20 and 23/63, reader 2/3) of asymptomatic volunteers had at least one positive MR finding for pincer-FAI. Patients with pincer or mixed-type FAI had cranial retroversion of the acetabulum of -0.2° ± 7.1 (mean ± standard deviation) for reader 1 and -0.3° ± 5.5/-0.2° ± 4.8 for reader 2 / reader 3, while asymptomatic volunteers had an anteversion of 6.2° ± 6.4 (reader 1) and 3.2° ± 4.9/3.1° ± 6.5 (readers 2/3): This difference was statistically significant (P ≤ 0.002), but there was a large overlap between the groups. Acetabular depth measurements were very similar for patients with either pincer or mixed-type FAI (5.1-5.3 mm ± 3.1) and volunteers (5.2-6.1 mm ± 2.6), without a statistically significant difference (P ≤ 0.50). Lateral center-edge angle was also similar in patients with either pincer or mixed-type FAI (32.1-35.1° ± 9.1) and volunteers (30.7-33.2° ± 6.5), without a statistically significant difference (P ≤ 0.28).

DATA CONCLUSION

There is a large overlap in pincer-type MRI findings between patients with symptomatic FAI and asymptomatic volunteers. More than a third of volunteers exhibited at least one positive pincer-type MRI finding.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1296-1303.

Prevalence of vitamin D insufficiency in radiologists: a cross-sectional study

OBJECTIVE

To compare the prevalence of vitamin D insufficiency between radiologists and a control group of non-radiologists.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted at the Swiss Congress of Radiology in May of 2016. Attendees (radiologists and non-radiologists) were asked to give a venous blood sample to measure vitamin D (25-hydroxyvitamin D) blood serum level. Vitamin D insufficiency was defined as < 50 nmol/l (30 ng/ml). We collected information on profession, age, gender, vitamin D supplements, recent sunny vacation, and eating fish. We compared vitamin D between radiologists and non-radiologists.

RESULTS

A total of 137 radiologists (mean age, 38 ± 10 years) and 164 non-radiologists (mean age, 40 ± 12 years) participated in the study. Prevalence of vitamin D insufficiency in both groups was similar (58.4% (80/137) vs. 53.7% (88/164); p = 0.240). Forty-three participants were under vitamin D supplementation. In those without supplementation, we found no difference in vitamin D between groups (44.0 ± 16.2 nmol/l (17.6 ± 6.5 ng/ml) vs. 44.4 ± 16.9 nmol/l (17.8 ± 6.8 ng/ml); p = 0.757). Average vitamin D levels for radiologists were slightly lower (-0.98 nmol/l (0.39 ng/ml), 95% confidence interval - 5.96 to 4.00 (- 2.38 to 1.6 ng/ml); p = 0.699), when adjusting for the potential confounders, but not statistically significant. The odds ratio of vitamin D insufficiency for radiologists versus non-radiologists was 1.7 (95% CI = 0.94-3.06; p = 0.078) after adjusting for the other independent variables.

CONCLUSIONS

The prevalence of vitamin D insufficiency in radiologists was high (58.4%), but not substantially higher than in non-radiologists.

Osteofibrous Dysplasia with Rhabdoid Elements in a 38-Year-Old Man with Spontaneous Regression Over Five Years: A Case Report

CASE

A 38-year-old man presented with multifocal, partially confluent osteolytic lesions in the proximal dia-meta-epiphyseal region of the proximal aspect of the left tibia, which had been found incidentally when a radiograph was made after a rotational knee injury. When the results of a percutaneous core needle biopsy proved inconclusive, an open biopsy was performed. Osteofibrous dysplasia (OFD) with scattered groups of plump cells with a rhabdoid phenotype, shown to express both vimentin and pan-cytokeratin, was found. Because the lesion was an incidental finding, we decided to proceed with observation. Three months after the open biopsy, imaging showed marked regression of the lesion; there was nearly complete normalization 5 years later.

CONCLUSION

To our knowledge, there has been only 1 prior reported case with these pathologic features, and there have been no reports of complete spontaneous regression in an adult patient with OFD. Treatment recommendations for OFD and for OFD-like adamantinoma range from observation to aggressive resection.

Frequency of inflammatory-like MR imaging findings in asymptomatic fingers of healthy volunteers

OBJECTIVE

To describe the frequency of inflammatory-like findings on MR imaging in asymptomatic volunteers and compare them with patients with known rheumatoid arthritis and psoriatic arthritis.

MATERIALS AND METHODS

MR images of fingers in 42 asymptomatic volunteers and 33 patients with rheumatoid/psoriatic arthritis were analyzed. The Outcome Measures in Rheumatology Clinical Trials (OMERACT) Rheumatoid/Psoriatic Arthritis MRI Scoring System (RAMRIS/PsAMRIS) and tenosynovitis scoring system were used to assess: bone marrow edema (BME), erosions, tendon sheath fluid/tenosynovitis, joint effusion, and soft-tissue edema. Findings and scores were compared between volunteers and patients. Inter-reader agreement was calculated (intraclass correlation coefficients, ICC).

RESULTS

In volunteers, tendon sheath fluid was very common in at least one location (42/42 volunteers for reader 1, 34/42 volunteers for reader 2). BME, erosions, joint effusion, and soft-tissue edema were absent (except one BME in the 3rd proximal phalanx for reader 1). Tendon sheath fluid scores in volunteers and tenosynovitis scores in patients were high (reader 1, 7.17 and 5.39; reader 2, 2.31 and 5.45). Overall, inter-reader agreement was substantial (ICC = 0.696-0.844), except for tendon sheath fluid (ICC = 0.258).

CONCLUSION

Fluid in the finger flexor tendon sheaths may be a normal finding and without gadolinium administration should not be interpreted as tenosynovitis. Bone marrow edema, erosions, joint effusion, and soft-tissue edema in the fingers most likely reflect pathology if present.

Measurement of acetabular version based on biplanar radiographs with 3D reconstructions in comparison to CT as reference standard in cadavers

To quantify acetabular version using 3 D reconstructions based on biplanar radiographs (BPR) with CT as reference standard. No institutional review board approval was needed. Nine dry-bone pelvises underwent BPR in five different positions (rotation/tilt). The 3 D models of each pelvis were reconstructed by two radiologists on the basis of anatomical landmarks using semi-automated software. Automated software was used to assess the 3 D models and to calculate acetabular versions perpendicular to the anterior pelvic plane on all levels in the craniocaudal direction in 1 mm steps. Transverse CT images perpendicular to the anterior pelvic plain were reconstructed through the acetabulum in 1 mm steps. Both readers measured acetabular version on each image. Inter-reader agreement was calculated. Measurements based on BPR and CT were compared. Inter-reader agreement was almost perfect for BPR-based acetabular version measurements (ICC (intraclass correlation coefficient) = 0.920, P < 0.0005) and CT (ICC = 0.990, P < 0.0005). Correlation of acetabular versions between the five BPR-positions was substantial/almost perfect (ICC = 0.722-0.887 and 0.749-0.872 for readers 1 and 2, respectively; most P < 0.0005). The acetabular version measurements between the ap-positioning from BPR and CT showed moderate agreement (mean CCC (concordance correlation coefficient) = 0.733 for reader 1, CCC = 0.755 for reader 2). Acetabular version on multiple levels can be measured using BPR and dedicated post-processing software and is relatively independent of pelvic rotation and tilt. Clin. Anat. 30:591-598, 2017. © 2017 Wiley Periodicals, Inc.

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 Pearson's 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.

Hip Imaging in Athletes: Sports Imaging Series

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016.

Femoral and tibial torsion measurements in children and adolescents: comparison of MRI and 3D models based on low-dose biplanar radiographs

OBJECTIVE

The aim of our study was to evaluate the reliability and interchangeability of femoral (FT) and tibial torsion (TT) measurements in children using magnetic resonance (MR) imaging compared to measurements on 3D models based on biplanar radiographs (BPR).

MATERIALS AND METHODS

FT and TT were measured in 60 children (mean age 10.1 years; range 6.2-16.2 years; 28 female) using axial MR images by two readers. MR measurements were compared to measurements based on BPR-3D models by two separate independent readers. Interreader and intermethod agreements were calculated using descriptive statistics, the intraclass correlation coefficient (ICC), and Bland-Altman analysis.

RESULTS

FT/TT was -8.4°-54.1°/0°-45.9° on MR images and -13°-63°/4°-52° for measurements on BPR-3D models. The median of difference between the two methods was -0.18° (range -13.6°-19.1°) for FT and -0.20° (range -18.4°-9.5°) for TT, respectively. Interreader agreement (ICC) of FT/TT measurements was 0.98/0.96 on MR images and 0.98/0.94 on BPR 3D models. Intermethod agreement (ICC) for MR measurements was 0.95 [95% confidence interval (CI), 0.93-0.96] for FT and of 0.86 (CI, 0.24-0.95) for TT. Mean interreader differences at MR were 3.1° (0.0°-8.0°) for FT and 3.2° (0.1°-9.5°) for TT. On Bland-Altman plots all measurements were within the 95% limit of agreement (-10.8°; 11.5° for FT; -14.6°; 4.2°) for TT-except for five measurements of FT and six measurements of TT.

CONCLUSION

FT measurements on MR images are comparable to measurements using BPR-3D models. TT measurements differ between the two modalities, but the discrepancy is comparable to measurement variations between CT and BPR.

Upright weight-bearing CT of the knee during flexion: changes of the patellofemoral and tibiofemoral articulations between 0° and 120°

PURPOSE

To prospectively compare patellofemoral and tibiofemoral articulations in the upright weight-bearing position with different degrees of flexion using CT in order to gain a more thorough understanding of the development of diseases of the knee joint in a physiological position.

MATERIALS AND METHODS

CT scans of the knee in 0°, 30°, 60° flexion in the upright weight-bearing position and in 120° flexion upright without weight-bearing were obtained of 10 volunteers (mean age 33.7 ± 6.1 years; range 24-41) using a cone-beam extremity-CT. Two independent readers quantified tibiofemoral and patellofemoral rotation, tibial tuberosity-trochlear groove distance (TTTG) and patellofemoral distance. Tibiofemoral contact points were assessed in relation to the anteroposterior distance of the tibial plateau. Significant differences between degrees of flexion were sought using Wilcoxon signed-rank test (P < 0.05).

RESULTS

With higher degrees of flexion, internal tibiofemoral rotation increased (0°/120° flexion; mean, 0.5° ± 4.5/22.4° ± 7.6); external patellofemoral rotation decreased (10.6° ± 7.6/1.6° ± 4.2); TTTG decreased (11.1 mm ±3.7/-2.4 mm ±6.4) and patellofemoral distance decreased (38.7 mm ±3.0/21.0 mm ±7.0). The CP shifted posterior, more pronounced laterally. Significant differences were found for all measurements at all degrees of flexion (P = 0.005-0.037), except between 30° and 60°. ICC was almost perfect (0.80-0.99), except for the assessment of the CP (0.20-0.96).

CONCLUSION

Knee joint articulations change significantly during flexion using upright weight-bearing CT. Progressive internal tibiofemoral rotation leads to a decrease in the TTTG and a posterior shift of the contact points in higher degrees of flexion. This elucidates patellar malalignment predominantly close to extension and meniscal tears commonly affecting the posterior horns.

Relationship of specific MRI findings to treatment outcomes in patients receiving transforaminal epidural steroid injections

OBJECTIVES

To determine whether specific MRI findings are related to outcomes after lumbar transforaminal epidural steroid injections (TFESI) and to assess the inter-rater reliability of imaging diagnosis.

MATERIALS AND METHODS

A prospective outcomes study on 156 consecutive patients with 1-month follow-up outcomes data and MRI within 3 months of TFESI was conducted. Pain levels (numerical rating scale) (NRS) were recorded prior to injection. Overall 'improvement' was determined using the Patients Global Impression of Change (PGIC) scale and NRS data were collected at three time points post injection. Two radiologists independently evaluated all images blinded to treatment outcome for reliability of diagnosis. The Chi-square test compared MRI findings for the senior radiologist to 'improvement'. NRS change scores were compared to MRI findings with the unpaired t-test or ANOVA. Kappa and percent agreement assessed inter-rater agreement of diagnosis.

RESULTS

The only abnormality linked to 'improvement' (p = 0.03) and higher NRS change scores (p = 0.0001) at 1 month was the disc herniation morphology 'protrusion + sequestration'. Patients with degeneration by osteophytes (p = 0.034), grade 3 foraminal nerve root compression (p = 0.01) and foraminal/extraforaminal location of herniation (p = 0.014) also had higher 1 month NRS change scores. Reliability of diagnosis was 'fair' to 'substantial' depending on MRI findings.

CONCLUSIONS

Patients with disc protrusion plus sequestration were significantly more likely to report overall improvement and more pain reduction at 1 month. Higher pain reduction was noted in patients with degeneration by osteophytes, grade 3 foraminal nerve root compression, or foraminal/extraforaminal disc herniation location.

Comparison of shear wave velocity measurements assessed with two different ultrasound systems in an ex-vivo tendon strain phantom

OBJECTIVE

The purpose of this study is to compare the reliability of SW velocity measurements of two different ultrasound systems and their correlation with the tangent traction modulus in a non-static tendon strain model.

MATERIALS AND METHODS

A bovine tendon was fixed in a custom-made stretching device. Force was applied increasing from 0 up to 18 Newton. During each strain state the tangent traction modulus was determined by the stretcher device, and SW velocity (m/s) measurements using a Siemens S3000 and a Supersonic Aixplorer US machine were done for shear modulus (kPa) calculation.

RESULTS

A strong significant positive correlation was found between SW velocity assessed by the two ultrasound systems and the tangent traction modulus (r = 0.827-0.954, p < 0.001), yet all SW velocity-based calculations underestimated the reference tissue tangent modulus. Mean difference of SW velocities with the S3000 was 0.44 ± 0.3 m/s (p = 0.002) and with the Aixplorer 0.25 ± 0.3 m/s (p = 0.034). Mean difference of SW velocity between the two US-systems was 0.37 ± 0.3 m/s (p = 0.012).

CONCLUSION

In conclusion, SW velocities are highly dependent on mechanical forces in the tendon tissue, but for controlled mechanical loads appear to yield reproducible and comparable measurements using different US systems.

Cervical Facet Joint Imaging-Guided Injections: A Comparison of Outcomes in Patients Referred Based on Imaging Findings Vs Palpation for Pain

OBJECTIVES

The purpose of this study was to compare outcomes of patients referred for cervical facet joint injections by either a medical doctor (MD) primarily basing the selection of facet levels on structural changes found on imaging vs a doctor of chiropractic (DC) selecting the levels for injection based on palpation for pain.

METHODS

This was a prospective cohort outcome study including 121 consecutive patients receiving cervical facet injections with completed outcomes questionnaires. Medical doctors referred 91 patients and DCs referred 30 patients. Baseline pain numerical rating scale (NRS) data were collected. Outcomes collected at 1 day, 1 week, and 1 month after injection included NRS pain levels and overall "improvement" using the Patient Global Impression of Change scale (primary outcome). The responses "much better" and "better" were considered "improved." The proportion improved was compared between the 2 groups using the χ(2) test. NRS change scores for the 2 groups were compared using the unpaired t test.

RESULTS

At 1 day, "improvement" was reported in 44.8% of DC-and 29.7% of MD-referred patients (P = .17). At 1 week, 37.9% of DC-and 21.3% of MD-referred patients reported improvement (P = .03). At 1 month, 50.0% of DC-and 31.0% of MD-referred patients reported improvement (P = .1).

CONCLUSIONS

A greater proportion of DC-referred patients (injection level based on palpation for pain) reported "improvement" at all follow-up time points. This finding reached statistical significance at 1 week. These findings may be because DCs use palpation for pain to determine injection level whereas MDs rely more on imaging findings. The results suggest that the reported moderate results of facet injections partially may be due to the inaccurate selection of the spinal level treated.

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.

Symptomatic, Magnetic Resonance Imaging-Confirmed Cervical Disk Herniation Patients: A Comparative-Effectiveness Prospective Observational Study of 2 Age- and Sex-Matched Cohorts Treated With Either Imaging-Guided Indirect Cervical Nerve Root Injections or Spinal Manipulative Therapy

OBJECTIVE

The purpose of this study was to compare the outcomes of overall improvement, pain reduction, and treatment costs in matched patients with symptomatic, magnetic resonance imaging-confirmed cervical disk herniations treated with either spinal manipulative therapy (SMT) or imaging-guided cervical nerve root injection blocks (CNRI).

METHODS

This prospective cohort comparative-effectiveness study included 104 patients with magnetic resonance imaging-confirmed symptomatic cervical disk herniation. Fifty-two patients treated with CNRI were age and sex matched with 52 patients treated with SMT. Baseline numerical rating scale (NRS) pain data were collected. Three months after treatment, NRS pain levels were recorded and overall "improvement" was assessed using the Patient Global Impression of Change scale. Only responses "much better" or "better" were considered "improved." The proportion of patients "improved" was calculated for each treatment method and compared using the χ(2) test. The NRS and NRS change scores for the 2 groups were compared at baseline and 3 months using the unpaired t test. Acute and subacute/chronic patients in the 2 groups were compared for "improvement" using the χ(2) test.

RESULTS

"Improvement" was reported in 86.5% of SMT patients and 49.0% of CNRI patients (P = .0001). Significantly more CNRI patients were in the subacute/chronic category (77%) compared with SMT patients (46%). A significant difference between the proportion of subacute/chronic CNRI patients (37.5%) and SMT patients (78.3%) reporting "improvement" was noted (P = .002).

CONCLUSION

Subacute/chronic patients treated with SMT were significantly more likely to report relevant "improvement" compared with CNRI patients. There was no difference in outcomes when comparing acute patients only.

Enthesitis of lumbar spinal ligaments in clinically suspected spondyloarthritis: value of gadolinium-enhanced MR images in comparison to STIR

OBJECTIVE

To compare detection of spinal ligament enthesitis between gadolinium-enhanced fat-saturated T1-weighted gadolinium-enhanced fat-saturated T1-weighted (T1+Gd) and STIR sequences in patients with suspected spondyloarthritis.

MATERIALS AND METHODS

Sixty-eight patients (37 males, 42 ± 14 years) with a sacroiliac-joint (SIJ) and lumbar spine MRI for suspected spondyloarthritis were prospectively included. Sagittal T1+Gd and STIR images of the lumbar spine were assessed by two readers for enthesitis of interspinous/supraspinous ligaments, and for capsulitis of facet-joints between T12-S1. Patients' MRI were grouped according to ASAS (Assessment of SpondyloArthritis international Society) criteria in positive (group A) or negative (group B) SIJs. Enthesitis/capsulitis were compared between groups. Interreader agreement was assessed.

RESULTS

Enthesitis/capsulitis per patient was statistically significantly more frequent with T1+Gd compared to STIR (p ≤ 0.007), except for interspinous ligaments for reader 1 (p = 0.455). Interspinous enthesitis, supraspinous enthesitis, and capsulitis were present with T1+Gd(STIR) in 64.7 %(72.1 %), 60.3 %(17.7 %), and 61.8 %(29.4 %) for reader 1, and 51.5 %(41.2 %), 45.6 %(7.4 %), and 91.2 %(45.5 %) for reader 2. There were 76.5 %(52/68) patients in group A and 23.5 %(16/68) in group B. Total number of enthesitis/capsulitis on T1+Gd was statistically significantly higher in group A than B (4.96 vs. 2.94, p = 0.026; 8.12 vs. 5.25, p = 0.041 for reader 1 and 2, respectively). Interreader agreement showed mixed results for interspinous/supraspinous/capsulitis but was higher on T1+Gd (ICC = 0.838/0.783/0.367; p ≤ 0.001) compared to STIR (ICC = 0.652/0.298/0.224; p ≤ 0.032).

CONCLUSION

In patients with suspected spondyloarthritis, enthesitis/capsulitis in the lumbar spine are common findings and more frequently/reliably detected with T1+Gd than STIR. In patients with positive SIJ-MRI, the total number of enthesitis/capsulitis in T1+Gd was higher compared to patients with negative SIJ-MRI.

Quantification of early fatty infiltration of the rotator cuff muscles: comparison of multi-echo Dixon with single-voxel MR spectroscopy

OBJECTIVES

To evaluate quantification of early fatty infiltration in supraspinatus muscles with magnetic resonance (MR) imaging using a T2*-corrected multi-echo 3D-gradient-echo Dixon-based sequence (multi-echo Dixon) and compare it to proton-MR-spectroscopy.

METHODS

Sixty subjects (mean age 46 years, 41 men) with good supraspinatus muscle quality on 1.5 T MR imaging were included. Fat percentage (FP) in the supraspinatus muscle was quantified using a multi-echo Dixon compared to single-voxel MR spectroscopy as reference standard. In 18 subjects the multi-echo Dixon was repeated to assess test-retest reliability. Measurements based on multi-echo Dixon were performed by two independent readers by placing regions-of-interest (ROIs) in the supraspinatus muscle corresponding to the MR-spectroscopy voxel. Intraclass and concordance correlation coefficients (ICC/CCC) were used for statistical analysis.

RESULTS

Test-retest reliability was substantial for reader 1 (ICC = 0.757) and almost perfect for reader 2 (ICC = 0.873). Inter-reader reliability for multi-echo Dixon was almost perfect (ICC = 0.893, P < .0005). Mean FP in all 60 subjects with multi-echo Dixon was 3.5 ± 1.6 for reader 1, 3.7 ± 1.8 for reader 2, and 2.8 ± 1.4 with MR spectroscopy. Correlation between multi-echo Dixon and MR spectroscopy was moderate (CCC = 0.641).

CONCLUSION

The multi-echo Dixon sequence is a reliable method and comparable to MR-spectroscopy for quantification of low levels of fatty infiltration in the supraspinatus muscle.

KEY POINTS

• Multi-echo Dixon for low fat quantification in muscles is reliable. • Multi-echo Dixon low fat quantification is comparable to single-voxel MR spectroscopy • Multi-echo Dixon detects substantial differences in fatty infiltration within Goutallier 0-1.

Whole Body Magnetic Resonance Imaging Features in Diffuse Idiopathic Skeletal Hyperostosis in Conjunction with Clinical Variables to Whole Body MRI and Clinical Variables in Ankylosing Spondylitis

OBJECTIVE

Discrimination of diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) can be challenging. Usefulness of whole-body magnetic resonance imaging (WB-MRI) in diagnosing spondyloarthritis has been recently proved. We assessed the value of clinical variables alone and in combination with WB-MRI to distinguish between DISH and AS.

METHODS

Diagnostic case-control study: 33 patients with AS and 15 patients with DISH were included. All patients underwent 1.5 Tesla WB-MRI scanning. MR scans were read by a blinded radiologist using the Canadian-Danish Working Group's recommendation. Imaging and clinical variables were identified using the bootstrap. The most important variables from MR and clinical history were assessed in a multivariate fashion resulting in 3 diagnostic models (MRI, clinical, and combined). The discriminative capacity was quantified using the area under the receiver-operating characteristic (ROC) curve. The strength of diagnostic variables was quantified with OR.

RESULTS

Forty-eight patients provided 1545 positive findings (193 DISH/1352 AS). The final MR model contained upper anterior corner fat infiltration (32 DISH/181 AS), ankylosis on the vertebral endplate (4 DISH/60 AS), facet joint ankylosis (4 DISH/49 AS), sacroiliac joint edema (11 DISH/91 AS), sacroiliac joint fat infiltration (2 DISH/114 AS), sacroiliac joint ankylosis (2 DISH/119 AS); area under the ROC curve was 0.71, 95% CI 0.64-0.78. The final clinical model contained patient's age and body mass index (area under the ROC curve 0.90, 95% CI 0.89-0.91). The full diagnostic model containing clinical and MR information had an area under the ROC curve of 0.93 (95% CI 0.92-0.95).

CONCLUSION

WB-MRI features can contribute to the correct diagnosis after a thorough conventional workup of patients with DISH and AS.

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).

Are the presence of MODIC changes on MRI scans related to "improvement" in low back pain patients treated with lumbar facet joint injections?

BACKGROUND

Modic changes (MC) have been linked with low back pain (LBP) and worse outcomes from some treatments. No studies have investigated the impact that MCs may have on patient outcomes from lumbar facet injections. Therefore, the purpose of this study is to investigate whether the presence of Modic changes is related to 'improvement' in patients undergoing imaging-guided lumbar facet injection therapy.

METHODS

Outcomes from 226 patients with MRI scans within 3 months of their imaging-guided lumbar facet injections were investigated to determine whether MCs are related to 'improvement' post injection. At 1 day, 1 week and 1 month post injection the Patients Global Impression of Change scale answers were collected by postal questionnaire. This was the primary outcome measure. The numerical rating scale for pain data was collected prior to treatment and at the same post injection time points. The MRI scans were independently evaluated by two examiners for the presence/absence of Modic changes and the type of Modic change if present. Kappa statistics were used for reliability of diagnosis analysis. Chi-squared test and logistic regression analysis tested MCs with 'improvement'.

RESULTS

Intra- and inter-examiner reliability for the diagnosis of MCs was Kappa = 0.77 and 0.74. Intra- and inter-examiner reliability for categorizing MCs was K = 0.77 and K = 0.78. At 1 month post injection 45.2 % of patients without MCs reported clinically relevant 'improvement' compared to 34.2 % of patients with MC I and 32.1 % of patients with MC II. However, this did not reach statistical significance. Logistic regression found that Modic changes were not predictive of 'improvement'.

CONCLUSIONS

There was a tendency for patients without MCs to have better outcomes but this did not reach statistical significance. The reliability of diagnosing MCs was substantial.

MR findings associated with positive distraction of the hip joint achieved by axial traction

PURPOSE

To determine which MR-arthrography findings are associated with positive hip joint distraction.

MATERIALS AND METHODS

One hundred patients with MR arthrography of the hip using axial traction were included. Traction was applied during the MR examination with an 8 kg (females) or 10 kg (males) water bag, attached to the ankle over a deflection pulley. Fifty patients showing joint space distraction were compared to an age- and gender-matched control group of 50 patients that did not show a joint distraction under axial traction. Two radiologists assessed the neck-shaft angle, lateral and anterior center-edge (CE) angles, CE angles in the transverse plane, extrusion index of the femoral head, acetabular depth, alpha angle, acetabular version, ligamentum teres, joint capsule and ligaments, iliopsoas tendon and the labrum.

RESULTS

Mean joint space distraction in the study group was 0.9 ± 0.6 mm. Patients with positive joint space distraction had significantly higher neck-shaft angles (control group 131.6 ± 5.4°/study group 134.1 ± 6.1°, p < 0.05), smaller lateral CE angles (38.1 ± 5.9°/34.6 ± 7.2°, p < 0.05), smaller overall transverse CE angles (161.4 ± 9.9°/153.6 ± 9.6°, p < 0.001), smaller acetabular depth (4.1 ± 2.4 mm/5.8 ± 2.5 mm, p < 0.01), higher alpha angles (53.5 ± 7.8°/59.2 ± 10.1°, p < 0.01) and a thicker ligamentum teres (4.7 ± 1.4 mm/5.4 ± 1.8 mm, p < 0.05). The other parameters revealed no significant differences. ICC values for interobserver agreement were 0.71-0.95 and kappa values 0.43-0.92.

CONCLUSION

Increased neck-shaft angles, small CE angles, small acetabular depth, higher alpha angles and a thick ligamentum teres are associated with positive joint distraction.

[CT and MRI of hip arthroplasty]

Metal-induced artifacts impair image quality of computed tomography (CT) and magnetic resonance imaging (MRI) in patients with hip prostheses. Due to new developments in metal artifact reduction both methods can now be used for evaluation of a painful hip prosthesis. Iterative reconstruction algorithms and dual-energy scans are among the newer CT techniques for artifact reduction, while slice-encoding for metal artifact correction (SEMAC) and multi-acquisition variable-resonance image combination (MAVRIC) have introduced substantial improvements for MRI. Loosening of the hip prosthesis, osteolysis from small wear particles and pseudotumors in metal-on-metal prostheses are specific pathologies in patients with total hip arthroplasty. Other causes of painful hip prostheses are infections, fractures, tendinopathies, tendon ruptures, muscle and nerve alterations and heterotopic ossifications.

Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses

BACKGROUND

To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal.

METHODS

Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists.

RESULTS

A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used.

CONCLUSION

The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla.

Are Modic changes related to outcomes in lumbar disc herniation patients treated with imaging-guided lumbar nerve root blocks?

OBJECTIVE

To compare outcomes after imaging-guided transforaminal lumbar nerve root blocks in MRI confirmed symptomatic disc herniation patients with and without Modic changes (MC).

METHODS

Consecutive adult patients with MRI confirmed symptomatic lumbar disc herniations and an imaging-guided lumbar nerve root block injection who returned an outcomes questionnaire are included. Numerical rating scale (NRS) pain data was collected prior to injection and 20-30 min after injection. NRS and overall improvement were assessed using the patient's global impression of change (PGIC) scale at 1 day, 1 week and 1 month post injection. The proportion of patients with and without MC on MRI as well as Modic I and Modic II was calculated. These groups were compared for clinically relevant 'improvement' using the Chi-squared test. Baseline and follow-up NRS scores were compared for the groups using the unpaired t-test.

RESULTS

346 patients are included with MC present in 57%. A higher percentage of patients without MC reported 'improvement' and a higher percentage of patients with MC reported 'worsening' but this did not reach statistical significance. The numerical scores on the PGIC and NRS scales showed that patients with MC had significantly higher pain and worse overall improvement scores at 1 month (p=0.048 and p=0.03) and a significantly lower 1 month NRS change score (p=0.04).

CONCLUSIONS

Patients with MRI confirmed symptomatic lumbar disc herniations and MC report significantly lower levels of pain reduction after a lumbar nerve root block compared to patients without MC.

The carpometacarpal joint of the thumb: MR appearance in asymptomatic volunteers

PURPOSE

To prospectively characterize the MR appearance of the carpometacarpal (CMC) joint of the thumb in asymptomatic volunteers.

MATERIALS AND METHODS

Thirty-four asymptomatic volunteers (17 women, 17 men, mean age, 33.9 ± 9.2 years) underwent MR imaging of the thumb after approval by the local ethical committee. Two musculoskeletal radiologists independently classified visibility and signal intensity (SI) characteristics of the anterior oblique (AOL/beak ligament), the posterior oblique (POL), the intermetacarpal (IML), and the dorsoradial ligaments (DRL) on a three-point Likert scale. The thickness of all ligaments, cartilage integrity, and presence of joint fluid were assessed. The alignment of the first metacarpal base with the trapezium was quantified on sagittal and coronal planes.

RESULTS

The ligaments of the CMC joint were constantly visible in all volunteers for the POL and IML, and in all but one for the AOL and DRL. On intermediate-weighted fat-saturated images the POL (65 %/74 % reader 1/reader 2) and DRL (58 %/64 %) were commonly of increased SI, while the IML had a striated appearance in 91 %/76 % of subjects. The AOL showed a variable SI (36 %/42 % low, 27 %/27 % increased, 36 %/30 % striated). The IML was the thickest ligament with a mean of 2.9 mm/3.1 mm and the DRL the thinnest (1.2 mm/1.4 mm). There was a mean dorsal subluxation of 1.8 mm/2.0 mm and radial subluxation of 2.8 mm/3.4 mm of the metacarpal base. The AOL was significantly thicker in men (1.7 mm) than in women (1.2 mm; p = 0.02). Radial subluxation was significantly larger in men (3.4 mm) than in women (2.2 mm; p = 0.02). No subluxation in palmar or ulnar direction was seen.

CONCLUSIONS

Radial and dorsal subluxation of the CMC joint can be a normal finding in a resting position at MR imaging. The CMC ligaments showed a considerable variability of signal intensity with a typically striated IML; thickness of the AOL is typically less than 2.2 mm, of the POL typically less than 2.9 mm.

Symptomatic magnetic resonance imaging-confirmed lumbar disk herniation patients: a comparative effectiveness prospective observational study of 2 age- and sex-matched cohorts treated with either high-velocity, low-amplitude spinal manipulative therapy or imaging-guided lumbar nerve root injections

OBJECTIVES

The purpose of this study was to compare self-reported pain and "improvement" of patients with symptomatic, magnetic resonance imaging-confirmed, lumbar disk herniations treated with either high-velocity, low-amplitude spinal manipulative therapy (SMT) or nerve root injections (NRI).

METHODS

This prospective cohort comparative effectiveness study included 102 age- and sex-matched patients treated with either NRI or SMT. Numerical rating scale (NRS) pain data were collected before treatment. One month after treatment, current NRS pain levels and overall improvement assessed using the Patient Global Impression of Change scale were recorded. The proportion of patients, "improved" or "worse," was calculated for each treatment. Comparison of pretreatment and 1-month NRS scores used the paired t test. Numerical rating scale and NRS change scores for the 2 groups were compared using the unpaired t test. The groups were also compared for "improvement" using the χ(2) test. Odds ratios with 95% confidence intervals were calculated. Average direct procedure costs for each treatment were calculated.

RESULTS

No significant differences for self-reported pain or improvement were found between the 2 groups. "Improvement" was reported in 76.5% of SMT patients and in 62.7% of the NRI group. Both groups reported significantly reduced NRS scores at 1 month (P = .0001). Average cost for treatment with SMT was Swiss Francs 533.77 (US $558.75) and Swiss Francs 697 (US $729.61) for NRI.

CONCLUSIONS

Most SMT and NRI patients with radicular low back pain and magnetic resonance imaging-confirmed disk herniation matching symptomatic presentation reported significant and clinically relevant reduction in self-reported pain level and increased global perception of improvement. There were no significant differences in outcomes between NRI and SMT. When considering direct procedure costs, the average cost of SMT was slightly less expensive.