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To evaluate the MRI perfusion changes in patients with risk factors for osteonecrosis and normally appearing femoral heads prior to overt femoral head osteonecrosis.Fifty-eight patients (105 hips) were prospectively included in this ethics committee-approved study. There were 46 hips with no image anomalies and no risk factors for osteonecrosis of the femoral head (ONFH) risk factors, 38 with ONFH risk factors and no image abnormalities, and 21 with overt ONFH. All patients underwent DCE-MRI. Semi-quantitative (peak enhancement [PE], area under the curve [AUC], time to maximum enhancement [TME]) and quantitative perfusion parameters (volume plasma, KTRANS, and KEP) were calculated. Excessive alcohol consumption, corticosteroid use, and trauma were considered major risk factors for osteonecrosis of the femoral head.Measured at the femoral neck and compared to the healthy hips without OFNH risk factors, PE was significantly lower in the hips of patients with OFNH risk factors. Moreover, the difference was greater in females with risk factors, who presented significantly lower PE values (p = 0.0096). A PE threshold of 1.4% yielded a 92% sensitivity and 54% specificity for the presence of associated ONFH risk factors. The hips with overt OFNH compared to those with normally appearing showed an increase of PE of 45% in the neck (p0.014). Various epiphyseal femoral head perfusion parameters (PE, TME, AUC, and KDCE-MRI can identify perfusion marrow changes related to the presence of ONFH risk factors and adjacent to osteonecrosis areas.• Bone marrow perfusion changes may occur prior to overt ONFH and extend beyond the osteonecrosis area to the entire femoral head and neck. • Peak enhancement values were significantly reduced in patients with ONFH risk factors, compared to those without. • The presence of ONFH led to a significant increase in marrow perfusion adjacent to the osteonecrosis area.

To study the relationship between opportunistic CT bone density measurements and the occurrence of new vertebral fractures after percutaneous vertebral cementoplasty (PVC) of osteoporotic vertebral compression fractures (OVCF).A prospective analysis of retrospective data of 275 patients with OVCF treated by PVC between 2014 and 2019 with a clinico-radiological follow-up one year after treatment was conducted. Opportunistic bone density measurements were obtained at the trabecular bone of the L1 or an adjacent vertebra in Hounsfield units performed on the preoperative CT study. These density measurements values ​​were then compared between patients with and without new OCVF and in various population subgroups.There were 275 patients included, with 53 (19%) presenting a new OCVF and 24 (9%) developing a fracture cascade. The median opportunistic density measurements ​​in patients with recurrent OCVF were lower than those without (median 52[40.5]) HU and 77[49] HU)(p0.00001). Among the patients with new OVCF the median opportunistic density measurements in patients with fracture cascades were also lower than those without (44 HU and 62 HU, respectively) (p0.0096). Patients with density measurements under 61 HU were 3.6 times more likely to present recurrent fractures and those with density under 54 HU were 9.8 times more likely to develop a fracture cascade. The 36 HU threshold yielded a high specificity (90-91%) for the prediction of recurrent fractures and fracture cascade but with low sensitivity (respectively 26% and 37%).Low opportunistic vertebral density measurements are associated with a higher risk of OVCF and fracture cascades after PVC.• Low opportunistic density measurements are associated with a higher risk of OVCF and fracture cascades after PVC. • Measuring bone density before performing a PVC could help predict the risk of new vertebral fracture after treatment • Patient management could be adapted according to bone density.

To compare the diagnostic performance of scapholunate gap (SLG) measurements acquired with dart throwing (DT), radio-ulnar deviation (RUD), and clenching fist (CF) maneuvers on 4D CT for the identification of scapholunate instability.In this prospective study, 47 patients with suspected scapholunate interosseous ligament (SLIL) tears were evaluated from March 2015 to March 2020 with semiautomatic quantitative analysis on 4D CT. Five parameters (median, maximal value, range, and coefficient of variation) for SLG, lunocapitate angle (LCA), and radioscaphoid angle (RSA) obtained during DT maneuver were evaluated in patients with and without SLIL tears. CT arthrography was used as the gold standard for the SLIL status. The SLG values obtained were also compared with those obtained during CF and RUD maneuvers.Significant differences in all SLG- and LCA-derived parameters are found between patients with and without SLIL tears with DT (p0.003). The best diagnostic performance for the diagnosis of SLIL tears was obtained with median and maximal SLG values (sensitivity and specificity of 86-89% and 95%) and with maximal and range LCA values (sensitivity and specificity of 86% and 74%). No significant differences were observed for RSA values (p0.275). The SLG range obtained with DT maneuver was the only dynamic parameter statistically different between patients with partial and complete torn SLIL (p = 0.037).4D CT of the wrist during DT showed a similar performance than RUD and a better performance than CF for the differentiation between patients with and without SLIL tears.• Four-dimensional computed tomography can dynamically assess scapholunate instability. • The best results for differentiating between patients with and without SLIL tears were obtained with SLG median and maximal values. • The dart throwing and radio-ulnar deviation maneuvers yielded the best results for the dynamic evaluation of scapholunate instability.

To evaluate the image quality and clinical acceptance of a deep learning reconstruction (DLR) algorithm compared to traditional iterative reconstruction (IR) algorithms.CT acquisitions were performed with two phantoms and a total of nine dose levels. Images were reconstructed with two types of IR algorithms, DLR and filtered-back projection. Spatial resolution, image texture, mean noise value, and objective and subjective low-contrast detectability were compared. Ten senior radiologists evaluated the clinical acceptance of these algorithms by scoring ten CT exams reconstructed with the DLR and IR algorithms evaluated.Compared to MBIR, DLR yielded a lower noise and a higher low-contrast detectability index at low doses (CTDIDLR yielded a gain in objective detection and noise at lower dose levels with the best clinical acceptance among the evaluated reconstruction algorithms.• DLR yielded improved objective low-contrast detection and noise at lower dose levels. • Despite the differences in objective detectability among the algorithms evaluated, there were no differences in subjective detectability. • DLR presented significantly higher clinical acceptability scores compared to MBIR and HIR.

To compare four different methods for the quantitative assessment of dorsal scaphoid displacement in patients with scapholunate ligament tears.A total of 160 consecutive patients who underwent CT arthrography to evaluate a suspected scapholunate ligament tear were prospectively included in this study approved by the local ethics committee. MR images were available for 65 of these patients. Two readers independently evaluated the dorsal scaphoid displacement on conventional radiographs with the dorsal tangential line (DTL) method, the posterior radioscaphoid angle (PRSA) on both CT and MR, and the radioscaphoid congruency ratio on MR. These measurements were compared in groups of patients with and without scapholunate ligament tears.The measurement interobserver agreement was considered excellent for the DTL and the PRSA on CT (ICC = 0.93 and 0.88, respectively), good for the PRSA (ICC = 0.65) on MR, and moderate for the RSCR (ICC = 0.49). There was a significant increase in the values of DTL and PRSA on CT between patients with normal and ruptured SLIL (p0.0001). The same tendency was seen on MR-based methods, but these differences were only significant for one reader. The only method that allowed the differentiation between patients with normal and partially ruptured SLIL was the PRSA on CT. PRSA on CT yielded the best diagnostic performance for SLIL rupture (a sensitivity and a specificity of 70-82% and 70-72%).DTL on standard radiographs and the PRSA on CT are the most consistent imaging indicators of SDD with an excellent interobserver reproducibility.• Dorsal scaphoid displacement is an important prognostic factor in patients with scapholunate instability. • Quantitative assessment of dorsal scaphoid displacement can be performed on conventional radiographs and CT with an excellent reproducibility. • The posterior radioscaphoid angle on CT yielded the best diagnostic performance for the identification of scapholunate ligament tears and the only method allowing differentiation between patients with normal and partially torn ligaments.

Objectives: To ascertain the role of CT and conventional radiographs for the initial characterization of focal bone lesions. Methods: Images from 184 patients with confirmed bone tumors included in an ethics committee-approved study were retrospectively evaluated. The reference for benign-malignant distribution was based on histological analysis and long-term follow-up. Radiographs and CT features were analyzed by 2 independent musculoskeletal radiologists blinded to the final diagnosis. Lesion margins, periosteal reaction, cortical lysis, endosteal scalloping, presence of pathologic fracture, and lesion mineralization were evaluated. Results: The benign-malignant distribution in the study population was 68.5–31.5% (126 benign and 58 malignant). In the lesions that could be seen in both radiographs and CT, the performance of these methods for the benign-malignant differentiation was similar (accuracy varying from 72.8% to 76.5%). The interobserver agreement for the overall evaluation of lesion aggressiveness was considerably increased on CT compared to radiographs (Kappa of .63 vs .22). With conventional radiographs, 18 (9.7%) and 20 (10.8%) of the lesions evaluated were not seen respectively by readers 1 and 2. Among these unseen lesions, 50%–61.1% were located in the axial skeleton. Compared to radiographs, the number of lesions with cortical lysis and endosteal scalloping was 26–34% higher with CT. Conclusion: Although radiographs remain the primary imaging tool for lesions in the peripheral skeleton, CT should be performed for axial lesions. CT imaging can assess the extent of perilesional bone lysis more precisely than radiographs with a better evaluation of lesion fracture risk.

Hip arthroplasty is a frequently used procedure with high success rates. Its main indications are primary or secondary advanced osteoarthritis, due to acute fracture, osteonecrosis of the femoral head, and hip dysplasia. The goals of HA are to reduce pain and restore normal hip biomechanics, allowing a return to the patient’s normal activities. To reach those goals, the size of implants must suit, and their positioning must meet, quality criteria, which can be determined by preoperative imaging. Moreover, mechanical complications can be influenced by implant size and position, and could be avoided by precise preoperative templating. Templating used to rely on standard radiographs, but recently the use of EOS® imaging and CT has been growing, given the 3D approach provided by these methods. However, there is no consensus on the optimal imaging work-up, which may have an impact on the outcomes of the procedure. This article reviews the current principles of templating, the various imaging techniques used for it, as well as their advantages and drawbacks, and their expected results.

Background In this study we sought to evaluate the contribution of dynamic four-dimensional computed tomography (4DCT) relative to the standard imaging work-up for the identification of the dorsal intercalated segment instability (DISI) in patients with suspected chronic scapholunate instability (SLI). Methods Forty patients (22 men, 18 women; mean age 46.5 ± 13.1 years) with suspected SLI were evaluated prospectively with radiographs, arthrography, and 4DCT. Based on radiographs and CT arthrography, three groups were defined: positive SLI (n = 16), negative SLI (n = 19), and questionable SLI (n = 5). Two independent readers used 4DCT to evaluate the lunocapitate angle (LCA) (mean, max, coefficient of variation [CV], and range values) during radioulnar deviation. Results The interobserver variability of the 4DCT variables was deemed excellent (intraclass correlation coefficient = 0.79 to 0.96). Between the three groups, there was no identifiable difference for the LCAmean. The LCAmax values were lower in the positive SLI group (88 degrees) than the negative SLI group (102 degrees). The positive SLI group had significantly lower LCAcv (7% vs. 12%, p = 0.02) and LCArange (18 vs. 27 degrees, p = 0.01) values than the negative SLI group. The difference in all the LCA parameters between the positive SLI group and the questionable SLI group was not statistically significant. When comparing the negative SLI and questionable SLI groups, the LCAcv (p = 0.03) and LCArange (p = 0.02) values were also significantly different. The best differentiation between patients with and without SLI was obtained with a LCAcv and LCArange threshold values of 9% (specificity of 63% and sensitivity of 62%) and 20 degrees (specificity of 71% and sensitivity of 63%), respectively. Conclusion In this study, 4DCT appeared as a quantitative and reproducible relevant tool for the evaluation of DISI deformity in cases of SLI, including for patients presenting with questionable initial radiography findings. Level of evidence This is a Level III study.

To evaluate the added value of DWI, qualitative proton MR spectroscopy (H-MRS) and dynamic contrast-enhanced perfusion (DCE-P) to conventional MRI in differentiating benign and malignant non-fatty soft tissue tumors (NFSTT). From November 2009 to August 2017, 288 patients with NFSTT that underwent conventional and advanced MRI were prospectively evaluated. The study was approved by the local ethics committee. All patients signed an informed consent. A musculoskeletal (R1) and a general (R2) radiologist classified all tumors as benign, malignant, or indeterminate according to morphologic MRI features. Then, DWI, H-MRS, and DCE-P data of indeterminate tumors were analyzed by two additional radiologists (R3 and R4). Advanced techniques were considered individually and in combination for tumor benign-malignant differentiation using histology as the gold standard. There were 104 (36.1%) malignant and 184 (63.9%) benign tumors. Conventional MRI analysis classified 99 tumors for R1 and 135 for R2 as benign or malignant, an accuracy for the identification of malignancy of 87.9% for R1 and 83.7% for R2, respectively. There were 189 indeterminate tumors for R1. For these tumors, the combination of DWI and H-MRS yielded the best accuracy for malignancy identification (77.4%). DWI alone provided the best sensitivity (91.8%) while the combination of DCE-P, DWI, and H-MRS yielded the best specificity (100%). The reproducibility of the advanced imaging parameters was considered good to excellent (Kappa and ICC > 0.86). An advanced MRI evidence-based evaluation algorithm was proposed allowing to characterize 28.1 to 30.1% of indeterminate non-myxoid tumors. The prioritized use of advanced MRI techniques allowed to decrease by about 30% the number of non-myxoid NFSTT deemed indeterminate after conventional MRI analysis alone. • When morphological characterization of non-fatty soft tissue tumors is possible, the diagnostic performance is high and there is no need for advanced imaging techniques. • Following morphologic analysis, advanced MRI techniques reduced by about 30% the number of non-myxoid indeterminate tumors. • DWI is the keystone of advanced imaging techniques yielding the best sensitivity (91.8%). Optimal specificity (> 90%) is obtained by a combination of advanced techniques.

In this cadaveric study, we report quantitative dynamic four-dimensional CT evaluation of the effect on wrist kinematics of three intercarpal arthrodeses during radial and ulnar deviation. In five wrists, we successively performed scaphocapitate, four-corner and two-corner fusions. Four-dimensional CT examinations were performed prior to dissection and after each arthrodesis. The lunocapitate gap, posterior lunocapitate angle, radiolunate radial gap, radiolunate ulnar gap and radiolunate angle were assessed. After scaphocapitate arthrodesis, in radial deviation, we noted midcarpal diastasis and dorsal displacement of the capitate. In ulnar deviation, there was correction of that incongruence. After four-corner and two-corner fusions, in radial deviation, we noted radial radiolunate impingement and ulnar radiolunate incongruence. In ulnar deviation, after two-corner fusion, ulnar radiolunate impingement and radial radiolunate incongruence were present contrary to four-corner fusion. Our findings confirm that the constant radiocarpal and midcarpal congruence during radioulnar deviation in normal wrists is no longer possible with intercarpal kinematic modifications after these arthrodeses.

Background: MRI diagnostic criteria of shoulder adhesive capsulitis (AC) are nowadays widely used, but there is little information available on the association between MRI findings and clinical impairment. Purpose: To determine the correlation of MRI findings with the Constant–Murley Score (CMS), pain duration and symptoms at the one-year follow-up in AC patients. Materials and methods: This monocentric prospective study included 132 patients with a clinical diagnosis of shoulder AC who underwent shoulder MRI. Mean patient age was 54.1 ± 9.3 years, and there were 55 men and 77 women. A radiologist examined all patients and completed the CMS just prior to MRI. Pain duration was assessed along with the signal intensity and measured the maximal thickness of the inferior glenohumeral ligament (IGHL) by two radiologists. Medical record analysis was performed in a sub-group of 49 patients to assess prognosis approximately one year after the MRI examination. Linear regression analysis with the Pearson test and the Fisher exact test were used to determine the association between MRI findings and clinical impairment. Results: There was a significant difference in mean pain duration score (3.8 ± 1.2 versus 3.2 ± 0.9 and 3.8 ± 1.2 versus 3.2 ± 0.9, respectively, for readers 1 and 2) and in mean mobility scores (15.7 ± 8 points versus 19.6 ± 10.1 points and 15.8 ± 8.2 points versus 19.4 ± 10 points, respectively, for readers 1 and 2) in patients with a high IGHL signal compared to those with a low IGHL signal (p &lt, 0.05). IGHL was thicker in patients with clinical improvement at one-year follow-up compared to those presenting clinical stability or worsening (p &lt, 0.05). Conclusions: In patients with shoulder AC, the degree of signal intensity at the IGHL was inversely related to shoulder pain duration and range of motion, and a thickened IGHL indicated a favorable outcome at one-year follow-up.

Objectives To develop a practical step-by-step technique to precisely identify and differentiate tendons and ligaments attaching to the humeral epicondyles, to confirm through gross anatomical study the accurate structure identification provided by this technique and to determine the frequency at which each structure can be identified in healthy volunteers. Materials and methods First, ten fresh frozen cadavers (6 men, age at death = 58–92 years) were examined by two musculoskeletal radiologists and a step-by-step technique for the identification of tendons and ligaments at the level of humeral epicondyles was developed. Second, the accurate identification of structures was confirmed through gross anatomical study including anatomical sections on five specimens and layer-by-layer dissection technique on five others. Finally, 12 healthy volunteers (6 men, average age = 36, range = 28–52) were scanned by two radiologists following the same technique. Results An ultrasonographic technique based on the recognition of bony landmarks and the use of ultrasonographic signs to differentiate overlapping structures was developed and validated through gross anatomical study. In healthy volunteers, most tendons and ligaments were identified and well-defined in ≥ 80% of cases, except for the extensor carpi radialis brevis and extensor digiti minimi tendons on the lateral epicondyle (having common attachments with the extensor digitorum communis) and the palmaris longus tendon on the medial epicondyle (absent, or common attachment with the flexor carpi radialis). Conclusion A step-by-step approach to the ultrasonographic assessment of tendons and ligaments at the humeral epicondyles allowed accurate identification of and differentiation among these structures, in particular those relevant to pathological conditions.

Identify the most pertinent imaging features for solitary bone tumor characterization using a multimodality approach and propose a systematic evaluation system. Data from a prospective trial, including 230 participants with histologically confirmed bone tumors, typical “do not touch” lesions, and stable chondral lesions, were retrospectively evaluated. Clinical data, CT, and MR imaging features were analyzed by a musculoskeletal radiologist blinded to the diagnosis using a structured report. The benign-malignant distribution of lesions bearing each image feature evaluated was compared to the benign-malignant distribution in the study sample. Benign and malignant indicators were identified. Two additional readers with different expertise levels independently evaluated the study sample. The sample included 140 men and 90 women (mean age 40.7 ± 18.3 years). The global benign-malignant distribution was 67–33%. Seven imaging features reached the criteria for benign indicators with a mean frequency of benignancy of 94%. Six minor malignant indicators were identified with a mean frequency of malignancy of 60.5%. Finally, three major malignant indicators were identified (Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease) with a mean frequency of malignancy of 82.4%. A bone tumor imaging reporting and data system (BTI-RADS) was proposed. The reproducibility of the BTI-RADS was considered fair (kappa = 0.67) with a mean frequency of malignancy in classes I, II, III, and IV of 0%, 2.2%, 20.1%, and 71%, respectively. BTI-RADS is an evidence-based systematic approach to solitary bone tumor characterization with a fair reproducibility, allowing lesion stratification in classes of increasing malignancy frequency. Clinical trial number NCT02895633 . • The most pertinent CT and MRI criteria allowing bone tumor characterization were defined and presented. • Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease should be considered major malignant indicators associated with a frequency of malignancy over 75%. • The proposed evidence-based multimodality reporting system stratifies solitary bone tumors in classes with increasing frequencies of malignancy.

Hip arthroplasty (HA) is a frequently used procedure with high success rates, but 7% to 27% of the patients complain of persistent postsurgical pain 1 to 4 years post-operation. HA complications depend on the post-operative delay, the type of material used, the patient’s characteristics, and the surgical approach. Radiographs are still the first imaging modality used for routine follow-up, in asymptomatic and painful cases. CT and MRI used to suffer from metallic artifacts but are nowadays central in HA complications diagnosis, both having their advantages and drawbacks. Additionally, there is no consensus on the optimal imaging workup for HA complication diagnosis, which may have an impact on patient management. After a brief reminder about the different types of prostheses, this article reviews their normal and pathologic appearance, according to each imaging modality, keeping in mind that few abnormalities might be present, not anyone requiring treatment, depending on the clinical scenario. A diagnostic imaging workup is also discussed, to aid the therapist in his imaging studies prescription and the radiologist in their practical aspects.

BACKGROUND: To assess the influence on the spatial resolution of various Ultra-high-resolution computed tomography (CT) parameters and provide practical recommendations for acquisition protocol optimization in musculoskeletal imaging. METHODS: All acquisitions were performed with an Ultra-high resolution scanner, and variations of the following parameters were evaluated: field-of-view (150–300 mm), potential (80–140 KVp), current (25–250 mAs), focal spot size (0.4×0.5 to 0.8×1.3 mm(2)), slice thickness (0.25–0.5 mm), reconstruction matrix (512×512 to 2048×2048), and iso-centering (up to 85 mm off-center). Two different image reconstruction algorithms were evaluated: hybrid iterative reconstruction (HIR) and model-based iterative reconstruction (MBIR). CATPHAN 600 phantom images were analyzed to calculate the number of visible line pairs per centimeter (lp/cm). Task transfer function (TTF) curves were calculated to quantitatively evaluate spatial resolution. Cadaveric knee acquisitions were also performed. RESULTS: Under the conditions studied, the factor that most intensely influenced spatial resolution was the matrix size (additional visualization of up to 8 lp/cm). Increasing the matrix from 512×512 to 2048×2048 led to a 28.2% increase in TTF10% values with a high-dose protocol and a 5.6% increase with a low-dose protocol with no change in the number of visually distinguishable line pairs. The second most important factor affecting spatial resolution was the tube output (29.6% TTF10% gain and 5 additional lp/cm visualized), followed by the reconstruction algorithm choice and lateral displacement (both with a 4 lp/cm gain). Decreasing the slice thickness from 0.5 to 0.25 mm, led to an increase of 3 lp/cm (from 17 to 20 lp/cm) and a 17.3% increase in TTF10% values with no change in the “in-plane” spatial resolution. CONCLUSIONS: This study provides practical recommendations for spatial resolution optimization using Ultra-high-resolution CT.

Vascular lesions of the hand are common and are distinct from vascular lesions elsewhere because of the terminal vascular network in this region, the frequent hand exposure to trauma and microtrauma, and the superficial location of the lesions. Vascular lesions in the hand may be secondary to local pathology, a proximal source of emboli, or systemic diseases with vascular compromise. In most cases, ischaemic conditions are investigated with Doppler ultrasonography. However, computed tomography angiography (CTA) or dynamic contrast-enhanced magnetic resonance angiography (MRA) is often necessary for treatment planning. MR imaging is frequently performed with MRA to distinguish between vascular malformations, vascular tumours, and perivascular tumours. Some vascular tumours preferentially affect the hand, such as pyogenic granulomas or spindle cell haemangiomas associated with Maffucci syndrome. Glomus tumours are the most frequent perivascular tumours of the hand. The purpose of this article is to describe the state-of-the-art acquisition protocols and illustrate the different patterns of vascular lesions and perivascular tumours of the hand.

The aim of this study was to test the validity and reliability of the assessments of scapholunate (SL) instability status on 4-dimensional (4D) computed tomography (CT) using wrist arthroscopy as a reference standard.Thirty-three patients (16 men, 17 women; mean age, 48 ± 13 years) with suspected SL instability were evaluated prospectively with 4D-CT and wrist arthroscopy. Based on the arthroscopic testing of SL joint, 2 groups were defined: group 1 (n = 8) consisted of patients who had no, or slight, SL malalignment in the midcarpal space and group 2 (n = 25) consisted of patients who had moderate or severe SL malalignment. Two independent readers, who did not know the arthroscopic findings, used 4D-CT to evaluate the SL gap, lunocapitate angle (LCA), and radioscaphoid angle (mean and range values) during radioulnar deviation.The interobserver reliability was deemed good or excellent for most of the 4D-CT variables, except for the LCA range (moderate) and SL gap range (poor). For both readers, the SL gap mean, maximum, and minimum values were significantly higher (+67%, +78%, and +39%, respectively) and the LCA mean was significantly lower (-17%) in group 2 than in group 1. The radioscaphoid angle range values were lower (-34%) and the radioscaphoid angle mean values slightly higher (+4%) in group 2, but there was no significant difference between the 2 groups. The SL gap range values were also higher (+86% for R1 and +40% for R2) and the LCA range values also lower (-50% for R1 and -31% for R2) in group 2.Quantitative 4D-CT data corresponded well with the arthroscopic dynamic analysis of the SL joint in patients with suspected chronic SL instability.Diagnostic II.

International audience; OBJECTIVE. The purpose of this study was to evaluate the variation of the posterior radioscaphoid (RS) angle in patients with and without scapholunate ligament (SLL) tears during wrist radioulnar deviation. SUBJECTS AND METHODS. Seventy-three patients with clinically suspected scapholunate instability were prospectively evaluated with 4D CT and CT arthrography from February 2015 to April 2018. The posterior RS angle is formed between the articular surface of the scaphoid fossa of the radius and the most posterior point of the scaphoid in the sagittal plane. Two independent radiologists calculated this angle during radioulnar deviation. Posterior RS angles were correlated with the SLL status and the presence of a scapholunate diastasis on conventional stress radiographs. RESULTS. Readers 1 and 2 found mean posterior RS angles of 99° and 98°, respectively, in patients without and 107° and 111°, respectively, in patients with a scapholunate diastasis. The posterior RS angle amplitude varied 7.6-9.3° in the subgroups studied. The reproducibility of posterior RS angle measurement was considered good (intraclass correlation coefficient, 0.73). Mean posterior RS angles increased 6-10% and 12-14% when patients with an intact SLL were compared with those with partial tears and full tears, respectively (p < 0.001). These values also increased 8-13% when patients with diastasis were compared with those without (p < 0.0001). A dynamic acquisition was not necessary to assess this angle, with neutral posterior RS angles yielding a sensitivity of 64% and 72% and specificity of 79% and 94% for the diagnosis of SLL tears by readers 1 and 2, respectively. CONCLUSION. Posterior RS angle tended to increase with the severity of SLL tears and with the presence of scapholunate instability and yielded high sensitivity and specificity for the detection of SLL tears.

Purpose To evaluate the outcome of percutaneous vertebral cementoplasty (PVC) as the first-line treatment for traumatic thoracolumbar fractures within an ankylosed spinal segment. Materials and methods Thirty-one patients (15 men, 16 women; mean age: 79.2 ± 11 [SD] years; age range: 66–95 years) with thoracolumbar fractures within an ankylosed spine segment without neurological impairment treated with PVC were retrospectively evaluated. All patients were controlled at six weeks and one year after PVC. Ankylosing conditions, fractures sites and types, radiological consolidation, spinal complications were assessed. Anterior/posterior vertebral height ratios were measured before and after PVC. Postoperative pain relief and treatment success (radiological fracture consolidation) rates were considered. Results The 31 patients had a total of 39 fractures (19 stable [49%], 20 unstable [51%]) treated with PVC. Primary success rate of PVC (initial fracture consolidation without complication) was 61% (19/31). Seven patients (7/31; 23%) exhibited new fractures, and the secondary success rate of PVC (global fracture consolidation one year after repeat PVC) was 87% (34/39). Global consolidation rates of unstable fractures were 85% (17/20) of treated levels. Pain score was null in 84% patients (26/31) one year after PVC. There were no significant differences between pre-PVC (0.62 ± 0.18 [SD]; range: 0.22–0.88) and post-PVC (0.60 ± 0.18 [SD]; range: 0.35–0.88) vertebral height ratios (P = 0.94). Conclusion PVC conveys a high overall success rate and effectively controls pain in patients with vertebral fractures within ankylosed spine segments.

International audience; Objective: Evaluate and compare the image quality and acceptance of a full MBIR algorithm to that of an earlier full IR hybrid algorithm and filtered back projection (FBP).Methods: Acquisitions were performed with a 320 detector-row CT scanner with seven different dose levels. Images were reconstructed with three algorithms: FBP, full hybrid iterative reconstruction (HIR), and a full model-based iterative reconstruction algorithm (full MBIR). The sensitometry, spatial resolution, image texture, and low-contrast detectability of these algorithms were compared. Subjective analysis of low-contrast detectability was performed. Ten radiologists answered a questionnaire on image quality and confidence in full MBIR images in clinical practice.Results: The contrast-to-noise ratio of full MBIR was significantly higher than in the other algorithms (p < 0.0015). The spatial resolution was also higher with full MBIR at high frequencies (> 0.3 lp/mm). Full MBIR at low dose levels led to better low-contrast detectability and more inserts being identified with a higher confidence (p < 0.0001). Full MBIR was associated with a change in image texture compared to HIR and FBP. Eighty percent of radiologists judged general appearance and texture of full MBIR images worse than HIR. Moreover, compared with HIR, for 50% of radiologists, the diagnostic confidence on full MBIR images was worse. Questionnaire reliability was considered acceptable (Cronbach alpha 0.7).Conclusion: Compared to conventional iterative reconstruction algorithms, full MBMIR presented a higher image quality and low-contrast detectability and a worse acceptance among radiologists.Key points: • Full MBIR used led to an overall improvement in image quality compared with FBP and HIR. • Full MBIR leads to image texture change which reduces the confidence in these images among radiologists. • Awareness of the image texture change and improved quality of full MBIR reconstructed images could improve the acceptance of this technique in clinical practice.

To assess the use of CT with unfolded cylindrical projection (UCP) for rib fracture detection and characterization.The images from 60 polytraumatized patients who underwent whole body CT were evaluated for the presence and characterization of rib fractures (displaced or not, single or multiple). Two readers independently evaluated conventional CT images and UCP images in two readout sessions at least one month apart. All readouts were timed. A gold standard was established by two radiologists with 12 and 22 years of clinical experience based on the combined analysis of conventional and UCP reformats.Using UCP, the mean evaluation time was 27%-54% shorter (P = 0.01 and0.0001) while maintaining a comparable diagnostic performance (sensitivity and specificity of 68.4-79.1% and 99.5-99.6% for conventional reformats and 70.6-91.0% and 96.8-97.7% for UCP) and a good reproducibility (Kappa of 0.71). The multiple fracture detection ratio of UCP was similar to that of conventional reformats (80%). There were more false positives and false negatives using UCP and displaced fractures were harder to characterize.UCP yielded a diagnostic performance similar to that of conventional reformats for the detection of rib fractures with a good reproducibility and a noticeable reduction in evaluation time.

A wide variety of pathologies can affect the hallux sesamoid complex of the foot, including traumatic, micro traumatic, degenerative, inflammatory, vascular, infectious, and neoplastic conditions. Symptoms are quite nonspecific, mainly related to pain in the plantar surface of the first metatarsal head. In this context, imaging is important for the etiologic diagnosis of hallux sesamoid complex pathology with implications in patient management. The hallux sesamoid complex has a complex anatomy, and pathologic processes of this region are poorly known of radiologists. Besides, some entities such as "sesamoiditis" remain poorly defined in the literature. Schematically, conditions affecting sesamoids will be divided into two major groups: intrinsic anomalies (sesamoid bone being the center of the pathologic process) and extrinsic anomalies (diseases secondarily involving sesamoid bones). Thus, in this article, after a review of anatomical key points and pathologies affecting the hallux sesamoid complex, a practical multimodality approach for the diagnosis of hallux sesamoid pathologies will be proposed.

Purpose To determine the technical feasibility of four-dimensional (4D) CT for analysis of the variation of radioscaphoid angle (RSA) and lunocapitate angle (LCA) during wrist radioulnar deviation. Materials and Methods In this prospective study, 37 participants suspected of having scapholunate instability were evaluated from January 2015 to December 2016 with 4D CT and CT arthrography (mean age ± standard deviation, 42.3 years ± 15; range, 21-75 years; 27 men [mean age, 44 years ± 15] and 10 women [mean age, 38 years ± 14]). Five angular parameters for RSA and LCA variation during radioulnar deviation were calculated by two independent readers. CT arthrography was used as the reference standard method for scapholunate ligament tear identification. Results In the control group (n = 23), the mean values for RSA were 103° ± 8 and 104° ± 9, whereas the mean values for LCA were 86° ± 9° and 90° ± 11° with a coefficient of variation of 11% and 13% for reader 1 and reader 2, respectively. The interobserver and intraobserver agreements were excellent for RSA and substantial to excellent for LCA. In the pathologic group (n = 14), LCA amplitude, standard deviation, and maximal angle were lower for both readers with respect to the control group, measuring 36% and 44% (P = .003), 37% and 44% (P = .002), and 13% and 19% (P = .003), respectively. RSA amplitude did not show statistically significant results in the pathologic group (P > .13). LCA yielded the highest sensitivity (71%-93%), whereas RSA yielded the highest specificity (87%-100%). Conclusion Semiautomatic four-dimensional CT analysis of the wrist during radioulnar deviation is technically feasible and reproducible for evaluation of carpal kinematic abnormalities. © RSNA, 2018 Online supplemental material is available for this article .

The objective of our study was to evaluate the quality and reproducibility of semiautomatic measurements of the ankle in low-dose kinematic CT studies using a full model-based iterative reconstruction (MBIR).Kinematic CT was performed in five cadaveric ankles at three acquisition dose levels: standard dose (1020 mGy × cm), low dose (10% of the standard dose), and ultra-low-dose (1.5% of the standard dose). All images were reconstructed using a full MBIR algorithm. Two semiautomatic measurements (one distance and one angle) were performed by two readers. Registration error was evaluated. The bone aspect on CT and presence of metallic implants were considered in the analysis. The influence of dose on the measurements obtained, reproducibility, and image quality was assessed.With the standard- and low-dose protocols, registration quality was good (registration error, 0.65-4.72%), measurements were similar (p = 0.9), and reproducibility was excellent (intraclass correlation coefficient [ICC] = 0.881). With the ultra-low-dose protocol, the registration quality was poor, yielding measurements significantly different from the other protocols (p0.001) and poor reproducibility (ICC = 0.39). In a specimen with normal bone and no metal implant, the registration error was low (0.61-1.01%), measurements were similar (p0.5), and reproducibility was excellent (ICC, 0.885-0.996) for the three dose levels tested.Full MBIR allows reliable and reproducible measurements in ankle kinematic CT with a low-dose protocol, but an ultra-low-dose protocol may lead to unreliable results.

OBJECTIVE. The objective of this study was to assess the feasibility of T2 relaxation time measurements of the sacroiliac joints. SUBJECTS AND METHODS. The sacroiliac joints of 40 patients were imaged by 3-T MRI using an oblique axial multislice multiecho spin-echo T2-weighted sequence. Manual plotting and automatic subdivision of ROIs allowed us to obtain T2 values for up to 48 different areas per patient (posterior and anterior parts, sacral, intermediate, and iliac parts). Intraand interobserver reproducibility of T2 values were calculated after independent assessment by two musculoskeletal radiologists. RESULTS. A total of 1656 measurement sites could be analyzed. Mean (± SD) T2 values were 40.6 ± 6.7 ms and 41.2 ± 6.3 ms for observer 1 and 39.9 ± 6.6 ms for observer 2. The intraobserver intraclass correlation coefficient was 0.72 (95% CI, 0.70–0.74), and the interobserver intraclass correlation coefficient was 0.71 (95% CI, 0.68–0.72). CONCLUSION. Our study shows the feasibility of T2 relaxation time...

Bone marrow metabolism is complex and far from being fully understood. Novel aspects, such as the roles of bone marrow adiposity and vascularisation in bone metabolism currently attract attention. There is also a growing interest in the influence obesity might have on bone metabolism. Our objective was to determine the effect of BMI on bone marrow perfusion parameters using dynamic contrast-enhanced magnetic resonance imaging. This prospective monocentric study was approved by our local Ethics committee. Written consent was obtained. The right hip of 59 adults under 60 years old (mean age 37.5) was imaged with a dynamic 3D T1 spoiled gradient echo magnetic resonance imaging sequence. Mean BMI was 24.8 (+/− 4.4). Perfusion parameters were measured in the acetabulum and femoral neck, in the greater trochanter, in the femoral head epiphysis and in the subcutaneous adipose tissue. Associations between perfusion parameters and BMI were studied using a linear mixed model adjusted for age and sex effects. Our results showed that as the BMI increased, the exchanges between blood and bone marrow appeared more important (increased Ktrans and Kep values, p = 0.018 and p = 0.002 respectively) and the intramedullary blood flow appeared increased (lower time to peak values, p = 0.0002). In the subcutaneous fat, as the BMI increased, the vascularization decreased (lower area under the curve and initial slope values, p = 0.019 and p = 0.013 respectively). These results suggest that there is a relation between bone marrow perfusion and BMI, and that subcutaneous fat and bone marrow fat have different microvascular behaviours. Researchers must be aware of the effect of BMI on bone marrow perfusion parameters when they build a MR research protocol and analyse their data. A better understanding of these findings may provide the basis for the management of obesity-related bone changes.

Objectives Evaluate the clinical outcome of patients treated with CO2 laser surgery for early-stage glottic carcinomas followed up with 3-month laryngoscopy regardless of tumor grade and margins. Design Case series. Setting Retrospective review of the clinical records of patients treated at the ENT department of a tertiary university hospital. Participants and method Clinical records from patients with early-stage glottic carcinomas (Tis/T2) treated with curative intent by CO2 laser surgery in a ten-year period were evaluated. Regardless of tumor margin status, patients underwent fiber endoscopy 6 weeks after surgery and a systematic second look by direct laryngoscopy under general anesthesia at 3 months. Main outcome measures Local control, laryngeal preservation rate. Results Ninety-three patients were included. Disease control was obtained in 90/93 cases. Laryngeal preservation rate was 96.8%. Twenty patients had a local residual disease or recurrence after the first laser surgery, but 17 were salvaged (85%). Local residual disease and recurrence were more frequent in patients with advanced disease (T1b/T2), invasion of anterior commissure and "non-safe" margins. Conclusion The proposed follow-up scheme might be a valuable option, but with caution for positive or unevaluable margins as the latter is an independent risk factor for local recurrence. An early laser excision procedure (eg, within the first two months after surgery) or an alternative strategy may be discussed in this situation. "Watchful observation" should be reserved for compliant patients only so that the risk of missing potential recurrences is minimised.

To evaluate the use of two alternative picture archiving and communication systems (PACS) interface devices (a graphics tablet and a handheld controller) in clinical practice and on task-oriented exercises. Eleven senior radiologists were prospectively evaluated. The participants used the two tested interface devices for 10 working periods each and answered a questionnaire to evaluate the ergonomics of this experience. The prevalence of work-related musculoskeletal discomfort with the standard PACS interface set (mouse-keyboard-recording device) and these two devices was assessed. Exercises evaluating image scrolling and selection, image zooming and panning, image windowing, performing measurements, and reporting were performed with the standard PACS interface set and with the two tested devices. The sitting posture and hand position were evaluated. The general appreciation of the two alternative interface devices was considered to be similar to that of the standard interface set. The ergonomics of the handheld controller was considered to be slightly better than that of the standard interface set. The prevalence of musculoskeletal discomfort was 81%, 45%, and 18% for the standard interface set, graphics tablet, and handheld controller, respectively. With the graphics tablet and the handheld controller in 45% and 60%, respectively, there was a working posture change with respect to the standard interface set. The mean total exercise completion times of both tested devices were 27% higher than that of the standard interface set. Despite the increase in completion time of the task-oriented exercises, the tested devices were well accepted and considered to be more comfortable than the standard set. • Alternative PACS interface devices can be used as a substitute for the standard mouse-keyboard-recording device set with a potential improvement in work ergonomics and a reduction in work-related musculoskeletal discomfort.

We performed a prospective study to evaluate the values of dynamic four-dimensional computed tomography in assessing suspected chronic scapholunate instability. Forty patients were evaluated with radiographs, arthrography, and four-dimensional computed tomography. On plain radiographs and computed tomography, we found 16 patients with definite scapholunate instability, five with questionable scapholunate instability, and 19 with absence of scapholunate instability. We used four-dimensional computed tomography to evaluate the size of the scapholunate gap during radioulnar deviation. The mean and maximal values of the gap size were lowest in the patients with absence of scapholunate instability and highest in those with definite scapholunate instability. When comparing the scapholunate gap sizes of the patients with absent and questionable scapholunate instability, the range of the gap sizes was significantly higher in the patients with questionable scapholunate instability. We conclude that four-dimensional computed tomography aids assessment of chronic scapholunate instability, which allows the differentiation between patients without and those with definite or questionable scapholunate instability. Level of evidence: II

To compare the performance of different image reconstruction algorithms in the presence of small metal objects of different sizes and at different dose levels.A fresh bone of bovine femur was drilled with seven drill bits of increasing diameter. CT images with eight different dose levels were acquired and reconstructed with three algorithms: hybrid iterative reconstruction - HIR, Full model-based iterative reconstruction - full MBIR and a single energy metal artifact reduction - SEMAR. Trabecular distortion adjacent to metal was evaluated subjectively with a four-point scale. Edge profile artifacts were evaluated quantitatively by measuring drill bit diameter overestimation and the width of the low-density halo surrounding the drill bit.Trabecular distortion was higher with full MBIR compared to HIR and SEMAR (P 0.0001) and increased with drill bits larger than 1.2 mm and with doses lower than 18.1 mGy.cm. Low-density halos size and drill bit diameter overestimation decreased with full MBIR compared to the other two reconstruction algorithms and with SEMAR compared to HIR (P 0.0001). There was a mean drill bit overestimation of 0.56 ± 0.25 mm for full MBIR versus 0.68 ± 0.09 mm for SEMAR and mean low-density halo diameters of 0.03 mm ± 0.08 for full MBIR versus 0.42 mm ± 0.09 for SEMAR.Algorithm performance is influenced by dose levels and metal object size and no individual algorithm provides the best overall performance. Full MBIR is better in reducing edge artifacts and SEMAR is the best option for larger metal implants and low dose protocols.

The objective of this study was to describe the normal variation of bone marrow fat content in the proximal femur considering the influence of side, age, sex and body mass index using fat fraction MRI. From September 2012 to July 2016, the MRI of 131 patients (258 hips) considered to have a normal MRI appearance were retrospectively evaluated. Patient records were searched to allow calculation of the body mass index (BMI). Water-fat based chemical shift MRI was available for all patients included. Proton density fat fraction maps were calculated, and measurements were performed in the femoral epiphysis, intertrochanteric region, and greater trochanter. The influence of patient age, sex, hip side and BMI on fat fraction values was assessed. Fat fraction was significantly different in the different locations evaluated (P = 0.0001). Patient sex and age significantly influenced fat fraction values in all regions evaluated (P

International audience; Objective: to compare quantitative kinematic 4-D CT parameters between healthy volunteers and pathologic patients (joint stiffness or chronic ankle instability).Methods: Thirteen healthy volunteers without previous ankle trauma, 18 patients with clinical subtalar joint stiffness and 10 patients with chronic ankle instability diagnosed based on clinical and imaging findings were prospectively evaluated with 4-D CT. This study was approved by the local ethics committee and all patients signed an informed consent. The subtalar joint was evaluated during a prono-supination cycle. Two angles and two distances between the talus and the calcaneus were measured semi-automatically and independently by two readers. Measurement variations were compared in these three different groups.Results: There were statistically significant differences between axial and coronal talocalcaneal angles of healthy volunteers and patients with joint stiffness (p < 0.0001). The best sensitivities and specificities for the identification of subtalar joint stiffness were 92-100% and 74-94%. Mean and maximal posterior calcaneal facet uncovering were significantly lower in patients with chronic ankle instability patients compared to healthy volunteers (p < 0.006) with sensitivities and specificities of 92-95% and 80-92% respectively.Conclusion: Quantitative analysis in 4D CT can provide an objective criteria for the differentiation between healthy volunteers and patients with subtalar joint stiffness and chronic ankle instability.

The main objective of this study was to evaluate the diagnostic performance of the OpenRib software against the gold standard of autopsy in the detection of rib fractures. The secondary objective was to measure inter-rater agreement between each radiological reader. Thirty-six subjects who underwent postmortem CT and autopsy were included in this study. Rib fractures were first assessed during the autopsy by carefully dissecting and examining each rib. They were also independently evaluated by three readers using OpenRib software. This software produces from postmortem CT images a reformat of the rib cage and a display of all ribs in a single plane. Each reader was asked to determine if the rib was fractured and, if so, whether the fracture was single or multiple. After exclusions, 649 ribs were included in the statistical analysis. The two readers with a similar level of experience showed a satisfactory inter-rater agreement and a sensitivity of 0.73 and 0.83 with a specificity of 0.95 and 0.91. However, the experienced reader diagnosed significantly more fractures than the autopsy and the other two readers (p < 0.001). The use of automatic rib unfolding software in postmortem CT allows an efficient and accurate assessment of rib fractures and enables the diagnosis of fractures that cannot be detected during a standard autopsy. For now, this method seems to be the simplest that can be routinely performed; however, it requires training time in order to be sufficiently effective.

The purpose of this study was to show the application of quantitative 4D CT for subtalar joint evaluation in healthy volunteers and cadavers.Fifteen healthy volunteers with no history of subtalar joint trauma and three cadavers were prospectively evaluated with dynamic CT. The subtalar joint was evaluated during a pronosupination cycle. All acquisitions (cadavers and healthy volunteers) were performed using intermittent sequential mode with a 320-MDCT scanner. Angles and distances between the talus and the calcaneus were measured semiautomatically. Measurement variation was described in healthy volunteers and in cadavers, the latter before and after resection of the cervical and interosseous ligaments. The mean effective dose was below 0.1 mSv.In cadavers, mean increases in joint amplitude over 19% and of 22% were seen after partial ligament sectioning and after full ligament sectioning, respectively. The interobserver variability of the measurement ratios was considered to be excellent for three of the measurements made (ICC0.87) and moderate for the fourth (ICC = 0.57). The normal range of joint motion in healthy volunteers is described, with joint amplitudes varying from 6.4% to 22.8%.Quantitative dynamic CT of the subtalar joint can provide a detailed analysis of joint motion, supporting its potential role in the evaluation of subtalar instability.

International audience; Objective: The purpose of this study was to evaluate the diagnostic performance of quantitative perfusion parameters in 3-T MRI for benign-malignant differentiation in musculoskeletal tumors.Subjects and methods: Ninety-five patients with histologically proven musculoskeletal tumors were prospectively included in this study. All patients underwent 3-T contrast-enhanced perfusion MRI with T1 mapping. The extended Tofts pharmacokinetic model was used to obtain four semiquantitative and four quantitative perfusion parameters for each tumor. Two radiologists evaluated all images and manually placed the ROIs in consensus.Results: The 95 patients had 57 (59%) benign and 38 (41%) malignant tumors. Thirty-seven (39%) were bone and 58 (61%) were soft-tissue tumors. No significant differences were found in the perfusion parameters of benign and malignant tumors (p = 0.105-0.609). The best performance for benign-malignant differentiation was found for fractional volume of the extravascular extracellular space, which yielded 79% and 38% sensitivity and specificity. When soft-tissue tumors were considered, the transfer constant from plasma to the extravascular extracellular space exhibited a significant difference (p = 0.028) and had 79% and 27% sensitivity and specificity.Conclusion: Quantitative perfusion MRI had fair sensitivity and poor specificity for benign-malignant differentiation, which was similar to that obtained with semiquantitative parameters.

Purpose The purpose of this study was to determine the performance of CT arthrography for the diagnosis of intra-articular long head of biceps (LHB) tendon intrinsic lesions using arthroscopy findings as standard of reference. Material and methods CT arthrography studies of 98 patients (55 men, 43 women; mean age 54.8 ± 12.7 [SD] years [range: 16–77 years]) were retrospectively evaluated by two radiologists independently. Per operative arthroscopic images and surgical reports were retrospectively reviewed by a shoulder-specialist surgeon. Based on the analysis of arthroscopic images and the surgical reports, the LHB tendon was classified as normal (continuous with uniform tendon thickness), tendinopathy/partial rupture (focal change in tendon thickness and contour irregularities) and total rupture (total loss in tendon continuity). Imaging results were compared to those of surgery that served as standard of reference. Interobserver agreement was assessed. Results At arthroscopy, the LHB tendon was classified as normal in 38/98 (38.8%) patients, tendinopathic in 51/52 (52%) and totally ruptured in 9/98 (9.2%). The sensitivity and specificity of CT arthrography for the diagnosis of LHB tendinopathy were respectively 74% (95%CI: 60%–85%) and 93% (95%CI: 80%–99%) for reader 1 and 79% (95% CI: 67%–89%) and 95% (95% CI: 83%–99%) for reader 2. The sensitivity and specificity for the diagnosis of LHB tendon total ruptures were 100% (95%CI: 66%–100%) and 93% (95%CI: 86%–98%) for both readers. Interobserver agreements for the identification of the LHB tendon tendinopathy and total ruptures were excellent (kappa values of 0.94 and 0.96, respectively). Conclusion CT arthrography demonstrates good sensitivity and excellent specificity for the detection of intra-articular LHB tendinopathy and tear.

The aim of this article is to provide an overview of newer techniques and postprocessing tools that improve the potential impact of CT in forensic situations.CT has become a standard tool in medicolegal practice. Postmortem CT is an essential aid to the pathologist during autopsies. Advances in technology and software are constantly leading to advances in its performance.

The purpose of this prospective study was to ascertain the degree of variation of semi-quantitative and permeability parameters on DCE-MRI of normally appearing striated muscles. Dynamic contrast-enhanced MRI of the right hip was performed in 20 women and 24 men. Mean age was 39.1 ± 12.4 years. Two regions of interest (ROI) were drawn in twelve muscles of anterior, medial and gluteal compartments: a free-form ROI covering the largest muscle section and a smaller elliptical ROI. Semi-quantitative and permeability parameters were calculated using the extended Tofts model. Statistical analysis was performed with a linear mixed model to assess perfusion parameters variation. Intra- and inter-observer agreements were assessed. The intra-observer agreement was considered to be good for free-form ROI (minimum Intra-Class Coefficient (ICC) = 0.72) and moderate for elliptical ROI (minimum ICC = 0.51), while the inter-observer agreement was considered to be bad in both cases (minimum ICC = 0.11). There was a high inter-individual variation in most of the perfusion parameters evaluated. The average coefficients of variation were: Time To Peak = 9%, Area Under the Curve = 44%, Ve = 61%, Kep = 90%, Initial Slope = 99%, and Ktrans = 128%. A considerable variation in resting muscle perfusion parameters was seen. This could lead to errors in the analysis of muscle DCE-MRI studies or oncologic/non oncologic studies using muscle as a referential. Further studies targeted on acquisition protocols and post-processing software are necessary to improve the performance of muscle MR perfusion.

The management of Kienbock's disease is complex and constantly evolving in parallel with progress in the understanding of the pathophysiological mechanisms of this condition. Cross-sectional imaging techniques have an essential role in the diagnosis and prognostic assessment of this disease. CT allows the optimal study of the morpho-structure of lunate bone. MRI makes it possible to study bone marrow viability. As for CT arthrography, it allows to evaluate accurately articular cartilage of the different carpal joints. The evaluation of these different aspects of Kienbock's disease is essential for optimal treatment selection. Cross-sectional imaging also has an interest in post-treatment follow-up, by having a prognostic value and allowing the identification of post-operative complications. The purpose of this article is to review the contribution of cross-sectional imaging in the assessment of Kienbock's disease before and after treatment according to the most common surgical procedures. Pathophysiological mechanisms, predisposing factors, the different classifications and their interests will be discussed.

To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon’s canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists. Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH. The mean distances between the SB (d s) and DP (d p) and HH were 2.4 and 0.6 mm, respectively. The d s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it. This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon’s canal syndrome in cyclists.

International audience; The imaging characterization of musculoskeletal tumors can be challenging, and a significant number of lesions remain indeterminate when conventional imaging protocols are used. In recent years, clinical availability of functional imaging methods has increased. Functional imaging has the potential to improve tumor detection, characterization, and follow-up. The most frequently used functional methods are perfusion imaging, diffusion-weighted imaging (DWI), and MR proton spectroscopy (MRS). Each of these techniques has specific protocol requirements and diagnostic pitfalls that need to be acknowledged to avoid misdiagnoses. Additionally, the application of functional methods in the MSK system has various technical issues that need to be addressed to ensure data quality and comparability. In this article, the application of contrast-enhanced perfusion imaging, DWI, and MRS for the evaluation of bone and soft tissue tumors is discussed, with emphasis on acquisition protocols, technical difficulties, and current clinical indications.

International audience; Rationale and objectives: This study aimed to determine the value of dual-energy thoracic radiography in the diagnosis of pneumothorax considering the reader's experience.Materials and methods: Forty patients with a suspected pneumothorax, imaged with dual-energy chest radiographs, were divided into two groups: those with pneumothorax as the final diagnosis (n = 19) and those without (n = 21). The images were analyzed by 36 readers (5 interns, 16 residents, 15 senior physicians) for the presence or absence of pneumothorax during three readout sessions at 2-week intervals: standard images alone (session 1), dual-energy images with bone subtraction alone (session 2), and a combination of the two (session 3).Results: The number of correct responses increased 13.3% between sessions 1 and 2 (P < .001) and 9.4% between sessions 1 and 3 (P < .001). The mean sensitivity for pneumothorax detection was higher in sessions 2 (82%) and 3 (79%) compared to session 1 (70%). There was no statistically significant difference in specificity between the sessions. The number of correct responses for small volume pneumothoraces was higher in sessions 2 (10.6 ± 1.8) and 3 (10.1 ± 2.0) than in session 1 (8.9 ± 2.3), with a statistically significant difference between sessions 1 and 2 (P = .002) and between sessions 1 and 3 (P = .048).Conclusion: Bone subtracted dual-energy thoracic radiographs improve the detection sensitivity of pneumothorax, including in cases of small pneumothoraces, regardless of the reader's level or expertise.

The recommended exam for assessing chest trauma is a computed tomography (CT) chest scan. Using multi-planar reconstructions to evaluate a CT volume to assess the ribcage is a tedious and time-consuming task. We have designed an application that provides an automatically rendered unfolded unobstructed view of the entire ribcage using an unfolded cylindrical projection. This paper describes the underlying algorithm which has two main steps: ribcage segmentation and ribcage unfolding. The unfolding technique we developed preserves the relative size and location of the ribs and surrounding tissue, providing a natural anatomical reference for the reader. It also demonstrated usefulness to identify other musculoskeletal conditions such us scoliosis, calcified cartilage, bone tumours. To evaluate the usefulness of the application, we evaluated it on 70 representative CT chest scans. The evaluation was performed by a clinical expert who graded the specialized unfolded cylindrical projection view on a 5 point Likert scale according to the level of diagnostic confidence. Results showed that 84% of the studies were clinically useful (above grade 3). The algorithm is fully automatic and it runs in an average time of 24 s. The evaluation described in this paper gives positive initial feedback on the usefulness of the application. A recent multi-reader clinical study showed that using the specialized unfolded cylindrical projection view obtains similar diagnostic accuracy to conventional multi-planar reconstructions while reducing the reading time.