French community grid for the evaluation of radiological artificial intelligence solutions (DRIM France Artificial Intelligence Initiative).

PURPOSE: The purpose of this study was to validate a national descriptive and analytical grid for artificial intelligence (AI) solutions in radiology. MATERIALS AND METHODS: The RAND-UCLA Appropriateness Method was chosen by expert radiologists from the DRIM France IA group for this statement paper. The study, initiated by the radiology community, involved seven steps including literature review, template development, panel selection, pre-panel meeting survey, data extraction and analysis, second and final panel meeting, and data reporting. RESULTS: The panel consisted of seven software vendors, three for bone fracture detection using conventional radiology and four for breast cancer detection using mammography. A consensus was reached on various aspects, including general target, main objective, certification marking, integration, expression of results, forensic aspects and cybersecurity, performance and scientific validation, description of the company and economic details, possible usage scenarios in the clinical workflow, database, specific objectives and targets of the AI tool. CONCLUSION: The study validates a descriptive and analytical grid for radiological AI solutions consisting of ten items, using breast cancer and bone fracture as an experimental guide. This grid would assist radiologists in selecting relevant and validated AI solutions. Further developments of the grid are needed to include other organs and tasks.

Opportunistic Computed Tomography Screening for Osteoporosis and Fracture.

Osteoporosis is underdiagnosed and undertreated, leading to loss of treatment for the patient and high costs for the health care system. Routine thoracic and/or abdominal computed tomography (CT) performed for other indications can screen opportunistically for osteoporosis with no extra cost, time, or irradiation. Various methods can quantify fracture risk on opportunistic clinical CT: vertebral Hounsfield unit bone mineral density (BMD), usually of L1; BMD measurement with asynchronous or internal calibration; quantitative CT; bone texture assessment; and finite element analysis. Screening for osteoporosis and vertebral fractures on opportunistic CT is a promising approach, providing automated fracture risk scores by means of artificial intelligence, thus enabling earlier management.

Anatomical study of the medial calcaneal nerve using high-resolution ultrasound.

OBJECTIVES: To determine whether high-resolution ultrasound (US) can identify the course and relations of the medial calcaneal nerve (MCN). METHODS: This investigation was initially undertaken in eight cadaveric specimens and followed by a high-resolution US study in 20 healthy adult volunteers (40 nerves) by two musculoskeletal radiologists in consensus. The location and course of the MCN as well as its relationship to adjacent anatomical structures were evaluated. RESULTS: The MCN was consistently identified by US along its entire course. The mean cross-sectional area of the nerve was 1 mm2 (range 0.5-2). The level at which the MCN branched from the tibial nerve was variable, located a mean of 7 mm (range - 7-60) proximal to the tip of the medial malleolus. At the level of the medial retromalleolar fossa, the MCN was located inside the proximal tarsal tunnel a mean of 8 mm (range 0-16) posterior to the medial malleolus. More distally, the nerve was depicted in the subcutaneous tissue at the surface of the abductor hallucis fascia with a mean direct distance to the fascia of 1.5 mm (range 0.4-2.8). CONCLUSIONS: High-resolution US can identify the MCN at the level of the medial retromalleolar fossa, as well as more distally in the subcutaneous tissue at the surface of the abductor hallucis fascia. In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of nerve compression or neuroma, and perform selective US-guided treatments. CLINICAL RELEVANCE STATEMENT: In the setting of heel pain, sonography is an attractive tool for diagnosing compression neuropathy or neuroma of the medial calcaneal nerve, and enables the radiologist to perform selective image-guided treatments such as diagnostic blocks and injections. KEY POINTS: • The MCN is a small cutaneous nerve which rises from the tibial nerve in the medial retromalleolar fossa to the medial side of the heel. • The MCN can be depicted by high-resolution ultrasound along its entire course. • In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of neuroma or nerve entrapment, and perform selective ultrasound-guided treatments such as steroid injection or tarsal tunnel release.

Automatic deep learning-based assessment of spinopelvic coronal and sagittal alignment.

PURPOSE: The purpose of this study was to evaluate an artificial intelligence (AI) solution for estimating coronal and sagittal spinopelvic alignment on conventional uniplanar two-dimensional whole-spine radiograph. MATERIAL AND METHODS: This retrospective observational study included 100 patients (35 men, 65 women) with a median age of 14 years (IQR: 13, 15.25; age range: 3-64 years) who underwent conventional uniplanar two-dimensional whole-spine radiograph in standing position between January and July 2022. Ten most commonly used spinopelvic coronal and sagittal parameters were retrospectively measured without AI by a junior radiologist and approved or adjusted by a senior musculoskeletal radiologist to reach final measurements. Final measurements were used as the ground truth to assess AI performance for each parameter. AI performances were estimated using mean absolute errors (MAE), intraclass correlation coefficient (ICCs), and accuracy for selected clinically relevant thresholds. Readers visually classified AI outputs to assess reliability at a patient-level. RESULTS: AI solution showed excellent consistency without bias in coronal (ICCs ≥ 0.95; MAE ≤ 2.9° or 1.97 mm) and sagittal (ICCs ≥ 0.85; MAE ≤ 4.4° or 2.7 mm) spinopelvic evaluation, except for kyphosis (ICC = 0.58; MAE = 8.7°). AI accuracy to classify low Cobb angle, severe scoliosis or frontal pelvic asymmetry was 91% (95% CI: 85-96), 99% (95% CI: 97-100) and 94% (95% CI: 89-98), respectively. Overall, AI provided reliable measurements in 72/100 patients (72%). CONCLUSION: The AI solution used in this study for combined coronal and sagittal spinopelvic balance assessment provides results consistent with those of a senior musculoskeletal radiologist, and shows potential benefit for reducing workload in future routine implementation.

Vertebral trabecular bone texture analysis in opportunistic MRI and CT scan can distinguish patients with and without osteoporotic vertebral fracture: A preliminary study.

PURPOSE: To investigate the potential of texture parameters from opportunistic MRI and CT for the detection of patients with vertebral fragility fracture, to design a decision tree and to compute a Random Forest analysis for the prediction of fracture risk. METHODS: One hundred and eighty vertebrae of sixty patients with at least one (30) or without (30) a fragility fracture were retrospectively assessed. Patients had a DXA, an MRI and a CT scan from the three first lumbar vertebrae. Vertebrae texture analysis was performed in routine abdominal or lumbar CT and lumbar MRI using 1st and 2nd order texture parameters. Hounsfield Unit Bone density (HU BD) was also measured on CT-scan images. RESULTS: Twelve texture parameters, Z-score and HU BD were significantly different between the two groups whereas T score and BMD were not. The inter observer reproducibility was good to excellent. Decision tree showed that age and HU BD were the most relevant factors to predict the fracture risk with a 93 % sensitivity and 56 % specificity. AUC was 0.91 in MRI and 0.92 in CT-scan using the Random Forest analysis. The corresponding sensitivity and specificity were 72 % and 93 % in MRI and 83 and 89 % in CT. CONCLUSIONS: This study is the first to compare texture indices computed from opportunistic CT and MR images. Age and HU-BD together with selected texture parameters could be used to assess risk fracture. Machine learning algorithm can detect fracture risk in opportunistic CT and MR imaging and might be of high interest for the diagnosis of osteoporosis.

Texture Parameters Measured by UHF-MRI and CT Scan Provide Information on Bone Quality in Addition to BMD: A Biomechanical Ex Vivo Study.

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, and if the combination of texture parameters and areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry provided a better prediction of femoral failure than aBMD alone. The aBMD of 16 proximal femur ends from eight cadavers were investigated. Nineteen textural parameters were computed in three regions or volumes of interest for each specimen on UHF MRI and CT scan. Then, the corresponding failure load and failure stress were calculated thanks to mechanical compression test. aBMD was not correlated to failure load (R2 = 0.206) and stress (R2 = 0.153). The failure load was significantly correlated with ten parameters in the greater trochanter using UHF MRI, and with one parameter in the neck and the greater trochanter using CT scan. Eight parameters in the greater trochanter using UHF MRI combined with aBMD improved the failure load prediction, and seven parameters improved the failure stress prediction. Our results suggest that textural parameters provide additional information on the fracture risk of the proximal femur when aBMD is not contributive.

Intradiscal oxygen-ozone therapy for the treatment of symptomatic lumbar disc herniation: A preliminary study.

PURPOSE: To assess safety and effectiveness of computed tomography (CT)-guided intradiscal oxygen-ozone therapy (O2-O3 therapy) for the treatment of symptomatic lumbar disc herniation and radiological changes. MATERIALS AND METHODS: This study was conducted in twenty patients presenting lumbar disc herniation with resistant lumbar or lumbar radicular pain They underwent intradiscal oxygen-ozone therapy under CT guidance. They were treated at one- or two-disc levels, representing a total of 24 discs treated. MR imaging examinations were obtained before treatment and 2 months post-procedure to analyse treatment-related disc modifications including modification of the surfaces of the disc and of the herniated disc, and the variations in disc height according to the disc height index. Clinical outcomes were assessed using the visual analogue scale (VAS) to evaluate the severity of pain before the procedure, at primary (2 months) and at secondary (12 months) follow-ups. RESULTS: All the procedures were technically successful. The median VAS scores were 7.95 before the procedure, 3.9 at 2 months and 2.95 at 12 months. MRI analysis showed a significant decrease in herniation size at 2 months (-20%, p = 0.008). No immediate or late complications were observed. Only three patients (13.6%) underwent lumbar spine microdiscectomy in the year following ozone therapy. The treatment appeared to be more effective in cases of nerve root symptomatology. CONCLUSION: This study suggests that intradiscal O2-O3 therapy is safe and effective for the treatment of lumbar disc herniation associated with resistant lumbar or lumbar radicular pain.

Ultrasound-Guided Perimeniscal Injections: Anatomical Description and Feasibility Study.

OBJECTIVES: To anatomically describe the ultrasound (US)-guided perimeniscal injection technique, and evaluate its feasibility in the treatment of meniscal pain. METHODS: This work was initially undertaken in four cadaveric specimens with US-guided medial and lateral perimeniscal injection of China ink, followed by cadaveric dissection to assess injectate distribution, and potential injury to intra-articular and peri-articular structures. Then, 35 consecutive patients who underwent US-guided perimeniscal corticosteroid injection under local anesthesia for the treatment of symptomatic medial (30/35) or lateral (5/35) degenerative meniscal tear were retrospectively evaluated. Clinical outcome was assessed using a 0-10 numerical verbal rating scale (VRS) to evaluate severity of pain before, during, and after procedure at 6 weeks follow-up. RESULTS: Seven of eight (87.5%) ex vivo injections were accurate. A single inaccurate medial perimeniscal injection infiltrated the tibial collateral ligament instead of the perimeniscal area. No anatomical specimen exhibited intrameniscal injection or injury to regional structures. All procedures (35/35) performed clinically were technically successful. Median VRS scores were: 7 (range, 3-9) before procedure, 5 (range, 0-10) during procedure, and 1.5 (range, 0-9) after procedure at 6 weeks follow-up (P <.0001). No complication was observed. CONCLUSIONS: US-guided perimeniscal injections can accurately and safely deliver injectates in the perimeniscal area. In addition, our data suggest that perimeniscal corticosteroid injection provides significant symptom relief at 6 weeks in patients with meniscal pain. Further studies with long-term follow-up will be required to evaluate the role of perimeniscal injections in the nonoperative management of meniscal pathology.

Osteoid Osteoma: Percutaneous CT-guided Cryoablation Is a Safe, Effective, and Durable Treatment Option in Adults.

Background Cryoablation is playing an increasing role in the percutaneous treatment of bone tumors. However, despite its potential advantages over heat-based ablation techniques, the clinical safety and efficacy of cryoablation have not been established for osteoid osteoma treatment. Purpose To evaluate percutaneous CT-guided cryoablation for the treatment of osteoid osteoma in young patients and adults. Materials and Methods This retrospective study reviewed data from 50 consecutive patients who underwent percutaneous CT-guided cryoablation for the treatment of osteoid osteoma between January 2013 and June 2019 in a single institution. In 30 of 50 patients (60%), the procedure was carried out with the patient under local anesthesia and conscious sedation, with the cryoprobe covering the lesion from an extraosseous position, avoiding direct penetration of the nidus. Clinical and radiologic features, procedure-related data, visual analog scale (VAS) pain scores, complications, and overall success rate were evaluated. Statistical analyses were performed by using the nonparametric Friedman test and Wilcoxon signed rank test for repeated measures. Results Fifty patients (median age, 24 years; interquartile range [IQR], 19-38 years; 31 men) underwent CT-guided cryoablation for the treatment of osteoid osteoma, with a 96% (48 of 50 patients) overall clinical success rate. Of the two patients without clinical success, one patient had incomplete pain relief and the other experienced a recurrence of osteoid osteoma at 11 months, which was successfully treated with a second cryoablation procedure. The median VAS pain score was 8 (IQR, 7-8) before the procedure and 0 (IQR, 0-1; P < .001) after the procedure at both primary (6 weeks) and secondary (18-90 months) follow-up. Three of the 50 patients had minor complications (6%); no major complications were reported. Conclusion Osteoid osteoma was safely, effectively, and durably treated with CT-guided percutaneous cryoablation. In the majority of patients, treatment could be performed without general anesthesia, with the cryosphere covering the nidus from an extraosseous position. © RSNA, 2021.

Contact Pressure Between the Vocal Folds in Reinke's Edema: Experimental Observations on an Excised Human Larynx.

OBJECTIVE: To analyze the range of values of the contact pressure between the membranous vocal folds with Reinke's edema and to compare it to those observed in the absence of such a lesion. METHODS: Two human larynges were separately tested on the experimental bench, one of them with a bilateral loose swelling of the vocal folds. Once in a glottal prephonatory configuration, airflow was increased until achievement of self-sustained oscillations while recording aerodynamic, acoustic, electroglottographic data, and contact pressure between the folds. RESULTS: We observed well-documented variations in acoustical parameters, as the decrease of the fundamental frequency and the increase of the phonation threshold pressure. The results of the study also point to a significant increase in the amplitude of the contact pressure in presence of the Reinke's edema, and a lower degree of harmonicity of the produced sounds. CONCLUSION: This is the first report of ex vivo study of a larynx with Reinke's edema. It highlights the increase in the contact pressure during phonation, which possibly contributes to sustain the lesion once it appeared.

Acral FibroChondroMyxoid tumor: imaging features of a new entity.

"Acral FibroChondroMyxoid tumor" (AFCMT) is a recently described distinctive subtype of acral soft tissue tumor that typically arises on the fingers and toes. We herein present the unreported imaging features of AFCMT in a 44-year-old woman. This otherwise healthy patient was referred for a painful, slow-growing, soft tissue mass in the middle finger of her right hand. Initial radiographs and computed tomography showed a small lesion centered in the soft tissue of the ulnar aspect of the proximal phalanx, associated with scalloping of the underlying bone. Magnetic resonance imaging confirmed the presence of a well-circumscribed soft tissue tumor that exhibited relatively high T2-weighted signal intensity and marked enhancement after contrast administration. Subsequent excisional biopsy was performed. Histologically, the tumor was characterized by an abundant stroma displaying fibrous, chondroid, and myxoid areas. By immunohistochemistry, tumor cells stained for CD34, ERG, and focally S100 protein. RNA-sequencing allowed detection of THBS1-ADGFR5 gene fusion which confirmed the diagnosis of AFCMT. At 2-year follow-up, the patient remains free of recurrence. AFCMT is a previously unrecognized entity that may mimic chondroma and should be considered in the differential diagnosis of soft tissue tumors with cartilaginous or myxoid stroma in the extremities.

Correction to: Flat-panel CT arthrography for cartilage defect detection in the ankle joint: first results in vivo.

The names of the following authors were inadvertently inverted in the original manuscript.

Flat-panel CT arthrography for cartilage defect detection in the ankle joint: first results in vivo.

OBJECTIVES: The purpose of this study was to compare the diagnostic performance of flat-panel computed tomography (FPCT) arthrography for cartilage defect detection in the ankle joint to direct magnetic resonance (MR) arthrography using multidetector computed tomography (MDCT) arthrography as the reference standard. METHODS: Twenty-seven patients with specific suspicion of articular cartilage lesion underwent ankle arthrography with injection of a mixture of diluted gadolinium and iobitridol and were examined consecutively with the use of FPCT, MDCT, and 1.5 T MR imaging. FPCT, MDCT, and MR arthrography examinations were blinded and randomly evaluated by two musculoskeletal radiologists in consensus. In each ankle, eight articular cartilage areas were assessed separately: medial talar surface, medial talar trochlea, lateral talar trochlea, lateral talar surface, tibial malleolus, medial tibial plafond, lateral tibial plafond, and fibular malleolus. Findings at FPCT and MR were compared with MDCT assessments in 216 cartilage areas. RESULTS: For the detection of cartilage defects, FPCT demonstrated a sensitivity of 97%, specificity of 95%, and accuracy of 96%; and MR arthrography showed a sensitivity of 69%, specificity of 94%, and accuracy of 87%. FPCT and MR arthrography presented almost perfect agreement (κ = 0.87) and moderate agreement (κ = 0.60), respectively, with MDCT arthrography. Mean diagnostic confidence was higher for FPCT (2.9/3) than for MR (2.3/3) and MDCT (2.7/3) arthrography. CONCLUSIONS: FPCT demonstrated better accuracy than did 1.5 T MR arthrography for cartilage defect detection in the ankle joint. Therefore, FPCT should be considered in patients scheduled for dedicated imaging of ankle articular cartilage.

Anatomical study of the medial plantar proper digital nerve using ultrasound.

PURPOSE: To determine whether ultrasound allows precise assessment of the course and relations of the medial plantar proper digital nerve (MPPDN). MATERIALS AND METHODS: This work was initially undertaken in six cadaveric specimens and followed by a high-resolution ultrasound study in 17 healthy adult volunteers (34 nerves) by two musculoskeletal radiologists in consensus. Location and course of the MPPDN and its relationship to adjacent anatomical structures were analysed. RESULTS: The MPPDN was consistently identified by ultrasound along its entire course. Mean cross-sectional area of the nerve was 0.8 mm2 (range 0.4-1.4). The MPPDN after it branches from the medial plantar nerve was located a mean of 22 mm (range 19-27) lateral to the medial border of the medial cuneiform. More distally, at the level of the first metatarsophalangeal joint, mean direct distances between the nerve and the first metatarsal head and the medial hallux sesamoid were respectively 3 mm (range 1-8) and 4 mm (range 2-9). CONCLUSION: The MPPDN can be depicted by ultrasonography. Useful bony landmarks for its detection could be defined. Precise mapping of its anatomical course may have important clinical applications. KEY POINTS: • The medial plantar proper digital nerve (MPPDN) rises from the medial plantar nerve to the medial side of the hallux. • Because of its particularly long course and superficial position, the MPPDN may be subject to trauma, resulting in a condition known as Joplin's neuroma. • The MPPDN can be clearly depicted by ultrasound along its entire course. Precise mapping of its anatomical course may have important clinical applications.

Robot-assisted multi-level anterior lumbar interbody fusion: an anatomical study.

BACKGROUND: Minimally invasive surgical approaches still provide limited exposure. Access to the L2-L5 intervertebral discs during a single procedure is challenging and often requires repositioning of the patient and adopting an alternative approach. OBJECTIVES: Investigate the windows to the L2-L5 intervertebral discs to assess the dimensions of the interbody implants suitable for the procedure and evaluate the feasibility of multi-level lumbar intervertebral disc surgery in robot-assisted surgery (RAS) METHODS: Sixteen fresh-frozen cadaveric specimens underwent a retroperitoneal approach to access the L2-L5 intervertebral discs. The L2-L3 to L4-L5 windows were defined as the distance between the left lateral border of the aorta (or nearest common iliac vessel) and the medial border of the psoas, measured in a static state and after gentle medial retraction of the vascular structures. Two living porcine specimens and one cadaveric specimen underwent da Vinci robot-assisted transperitoneal approach to expose the L2-L3 to L4-L5 intervertebral discs and perform multi-level discectomy and interbody implant placement. RESULTS: The L2-L3 to L4-L5 intervertebral disc windows significantly increased from a static to a retracted state (p < 0.05). The mean L2-L3, L3-L4, and L4-L5 windows measured respectively 20.1, 21.6, and 19.6 mm in the static state, and 27.2, 30.9, and 30.3 mm after gentle vascular retraction. The intervertebral windows from L2-L3 to L4-L5 were successfully exposed through an anterior transperitoneal approach with the da Vinci robot on the cadaveric and living porcine specimens, and interbody implants were inserted. CONCLUSION: RAS appears to be feasible for a mini-invasive multi-level lumbar intervertebral disc surgery. The RAS procedure, longer and more expensive than conventional MIS approaches, should be reserved for elective patients.

Percutaneous cryoablation for the treatment of osteoid osteoma in the adult population.

PURPOSE: To evaluate the technical feasibility and efficacy of percutaneous cryoablation for the treatment of osteoid osteoma (OO) in adults. METHODS AND MATERIALS: 21 patients (12 male and nine female; mean age, 29.9 years) who underwent CT-guided percutaneous cryoablation for the treatment of OO were retrospectively evaluated. Procedures were carried out under local anaesthesia and conscious sedation in 13 patients, and under general anaesthesia in eight patients. Then, the ablation zone was evaluated with post-procedure magnetic resonance imaging at 6 weeks. Clinical outcome was assessed using a visual analogue scale (VAS) to evaluate severity of pain before procedure, as well as at primary (6 weeks) and secondary follow-up (6-40 months). RESULTS: All procedures were technically successful. Median VAS scores were: 8 (range, 5-10) before procedure and after procedure, respectively, 0 (range, 0-2; p < .0001) and 0 (range, 0-7; p < .0001) at primary and secondary follow-up. There were three minor complications (14.3%) and no major complication. A single patient reported symptom recurrence (4.8%) at secondary follow-up and successfully underwent a second cryoablation procedure. CONCLUSION: CT-guided percutaneous cryoablation is safe and effective in the treatment of OO in adults, and can be accomplished without general anaesthesia in selected cases. KEY POINTS: • CT-guided percutaneous cryoablation of osteoid osteoma is safe and effective • Cryoablation allows precise visual control of the aggregated iceball during procedure • Percutaneous cryoablation can be accomplished without general anaesthesia in selected cases • Another advantage of cryoablation is reduction of immediate postprocedural pain • Post-procedure MRI is helpful in the evaluation of technical success.

Surgical anatomy of the right gastro-omental artery: a study on 100 cadaver dissections.

PURPOSE: The gastro-omental artery (GOA) with the greater omentum (GO) is known for its high quality as a vascular graft, its resistance to infections as an omental flap and for its multiple applications in surgery. A better knowledge of anatomical variations of GO and its vascularization can improve the application in surgery and decrease complications. The purpose of this study was to measure diameters and lengths of the right GOA (RGOA) and study the interindividual variability of these anatomical structures. METHODS: In 100 cadaveric dissections, we carried out dissection of the RGOA and of the GO. In 70 unfixed cadavers, the transillumination technique was used to identify all RGOA branches. In the remaining 30 cadavers, prepared with Winckler's solution, barium sulfate with colored latex was injected. Digital X-ray was used to measure RGOA lengths, internal diameters and the distribution of the omental branches. The gastro-omental vein was also dissected. RESULTS: The mean proximal and distal diameters of RGOA were 2.68 (± 0.39) mm and 0.94 (± 0.24) mm, respectively. The mean length was 244.3 (± 34.4) mm. The thickness of the omentum ranged from 5 to 15.5 mm. The arteria omentalis magna, defined in this study for the fist time as the longest and widest omental branch, was present in 73.3% cases. The trans-omental arch was present in 6% cases. CONCLUSIONS: This morphometric study allowed us to define the vascularization and the anatomical variations of RGOA and GO. This may lead to improvement of applications in surgery and decrease complications.

Correlative Analysis of Vertebral Trabecular Bone Microarchitecture and Mechanical Properties: A Combined Ultra-high Field (7 Tesla) MRI and Biomechanical Investigation.

STUDY DESIGN: High-resolution imaging and biomechanical investigation of ex-vivo vertebrae. OBJECTIVE: The aim of this study was to assess bone microarchitecture of cadaveric vertebrae using ultra-high field (UHF) 7 Tesla magnetic resonance imaging (MRI) and to determine whether the corresponding microarchitecture parameters were related to bone mineral density (BMD) and bone strength assessed by dual-energy x-ray absorptiometry (DXA) and mechanical compression tests. SUMMARY OF BACKGROUND DATA: Limitations of DXA for the assessment of bone fragility and osteoporosis have been recognized and criteria of microarchitecture alteration have been included in the definition of osteoporosis. Although vertebral fracture is the most common osteoporotic fracture, no study has assessed directly vertebral trabecular bone microarchitecture. METHODS: BMD of 24 vertebrae (L2, L3, L4) from eight cadavers was investigated using DXA. The bone volume fraction (BVF), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) of each vertebra were quantified using UHF MRI. Measurements were performed by two operators to characterize the inter-rater reliability. The whole set of specimens underwent mechanical compression tests to failure and the corresponding failure stress was calculated. RESULTS: The inter-rater reliability for bone microarchitecture parameters was good with intraclass correlation coefficients ranging from 0.82 to 0.94. Failure load and stress were significantly correlated with BVF, Tb.Sp, and BMD (P < 0.05). Tb.Th was only correlated with the failure stress (P < 0.05). Multiple regression analysis demonstrated that the combination of BVF and BMD improved the prediction of the failure stress from an adjusted R = 0.384 for BMD alone to an adjusted R = 0.414. CONCLUSION: We demonstrated for the first time that the vertebral bone microarchitecture assessed with UHF MRI was significantly correlated with biomechanical parameters. Our data suggest that the multimodal assessment of BMD and trabecular bone microarchitecture with UHF MRI provides additional information on the risk of vertebral bone fracture and might be of interest for the future investigation of selected osteoporotic patients. LEVEL OF EVIDENCE: N /A.

Control of the glottal configuration in ex vivo human models: quantitative anatomy for clinical and experimental practices.

INTRODUCTION: The objective of this paper was to identify the determining factors of the glottal prephonatory configuration from the point of view of the resulting muscular actions (i.e., arytenoids adduction, membranous vocal fold adduction, and tension). MATERIALS AND METHODS: 21 human non-embalmed excised larynges (12 females and 9 males) were studied. Experiment A (11 larynges) studied four conditions of adduction of the vocal folds and arytenoids. Experiment B (10 larynges) studied the effect of cricothyroid approximation on the vocal fold length and the cricothyroid angle. RESULTS: Experiment A: The mean glottal area significantly decreased from 41.2 mm2 mean with no adduction, to 10.2 mm2 mean with arytenoid adduction, to 9.2 mm2 with membranous vocal fold adduction, and down to 1.1 mm2 with the combination of arytenoid and membranous adduction. The effect of the task was statistically significant. Experiment B: The length of vocal folds increased from 13.61 mm median to 14.48 mm median, and the cricothyroid angle decreased of 10.05 median along with cricothyroid approximation. DISCUSSION: The results of experiment A emphasize the sub-division of adductor intrinsic muscles in arytenoids adductors (i.e., LCA and IA), and membranous vocal fold adductor (i.e., TA). The results of experiment B quantify the effect of cricothyroid approximation on the vocal folds length. The implications of these results can be useful in both clinical practice and experimental studies.

A dynamic study of the anterior cruciate ligament of the knee using an open MRI.

Recent anatomical and radiological studies of the anterior cruciate ligament (ACL) suggest the ACL length and orientation change during knee flexion, and an open MRI sequencing during knee flexion enables a dynamic ACL analysis. This study's goal is to describe a normal ACL using a 1T open MRI and, in particular, variations in length and insertion angles at different degrees of flexion. Twenty-one volunteers with clinically healthy knees received a dynamic MRI with their knees in hyperextension, neutral position, and flexed at 45° and 90° angles. For each position, two radiologists measured the ACL lengths and angles of the proximal insertion between the ACL's anterior edge and the roof of the inter-condylar notch. Additionally, we measured the ACL's and the tibial plateau's distal angle insertion between their anterior edges and then compared these with the nonparametric Wilcoxon test. The ACL had a significant extension between the 90° flexion and all other positions (hyperextension: 31.75 ± 2.5 mm, neutral position: 32.5 ± 2.6 mm, 45°: 35.6 ± 1.6 mm, 90°: 35.6 ± 1.6 mm). There was also a significant increase of the angle insertion between the proximal 90° flexion and all other positions, as well as between hyperextension and bending to 45° (hyperextension: 2.45° ± 3.7°, neutral: 13.4° ± 9.7°, 45°: 33 25 ± 9.3, 90: 51.85° ± 9.3°). Additionally, there is a significant increase in the distal angle insertion for all positions (hyperextension: 133.2° ± 5.4°, neutral position: 134.95° ± 4.4°, 45°: 138.35° ± 5.9°, 90°: 149.15° ± 8.6°). Our study is the first to exhibit that a dynamic MRI has a significant ACL extension in vivo during bending. This concept opens the way for further studies to improve the diagnosis of traumatic ACL injuries using a dynamic MRI.