The AMADEUS score is not a sufficient predictor for functional outcome after autologous chondrocyte implantation (ACI) of the knee: data from the German Cartilage Registry (KnorpelRegister DGOU).

INTRODUCTION: The AMADEUS (Area Measurement And DEpth and Underlying Structures) score has advanced to a commonly used tool for MRI-based chondral defect severity grading prior to cartilage knee surgery. It was the intention of this study to assess the AMADEUS for a potential correlation with clinical data by patient-reported outcome measures (PROMs). METHODS: A total of 51 patients undergoing ACI (autologous chondrocyte implantation) between 2016 and 2022 were found eligible and retrospectively analyzed. All patients were registered in the German Cartilage Registry prior to surgery and follow-up data were collected using the Knee Osteoarthritis Outcome score (KOOS), the International Knee Documentation Committee (IKDC) Form and the numeric rating scale (NRS). Pre-operative MRI images were scored by three raters using the AMADEUS classification system, and an overall AMADEUS score was calculated which was subsequently correlated with pre- and post-operative PROMs. RESULTS: Mean patient age was 32.67 ± 8.37 years and mean defect size area 343.04 mm2 ± 139.45 mm2. No correlative capacity of the pre- and postoperative IKDC, KOOS or NRS scores was found with the AMADEUS final score or any of its subscores. From the pre- to postoperative visit, a significant improvement of the PROMs (IKDC: 45.53 ± 21.00 vs. 59.83 ± 17.93, p = 0.04; KOOS Pain: 58.00 ± 16.70 vs. 76.06 ± 19.20, p = 0.03; KOOS ADL: 64.17 ± 18.76 vs. 82.11 ± 16.68, p < 0.01; KOOS Sports: 26.11 ± 18.52 vs. 50.56 ± 23.94, p = 0.01; KOOS QOL: 25.50 ± 14.26 ± 45.28 ± 19.03, p = 0.00) was found. Intraclass correlation coefficients showed an overall good interrater agreement for the AMADEUS total score (ICC = 0.75). CONCLUSIONS: Study results suggest no correlative capacity of the AMADEUS with routinely used PROMs in patients undergoing ACI. Therefore, radiographically assessed cartilage defect characteristics poorly translate to pre- and postoperative patient-reported outcome data.

Rotational alignment of the lower extremity in the presence of total knee endoprosthesis: Reproducibility of torsion analyses using ultra-low-dose photon-counting CT.

PURPOSE: Leg torsion analysis can provide valuable information in symptomatic patients after total knee arthroplasty. However, extensive beam-hardening and photon-starvation artifacts limit diagnostic assessability and dose reduction potential. For this study, we investigated the reproducibility of rotational measurements in ultra-low-dose photon-counting CT with spectral shaping via tin prefiltration. MATERIAL AND METHODS: Employing a first-generation photon-counting CT, eight cadaveric specimens were examined with an established three-level scan protocol (hip: Sn 140, knee: Sn 100, ankle: Sn 100 kVp). In three body donors with unilateral knee endoprostheses, additional modified settings were applied (Sn 140 kVp at knee level). Protocols were executed with three dose levels (hip-knee-ankle, high-quality: 5.0-3.0-2.0 mGy, low-dose: 0.80-0.30-0.26 mGy, ultra-low-dose: 0.25-0.06-0.06 mGy). Six radiologists performed torsion analyses, additionally reporting their diagnostic confidence. Intraclass correlation coefficients (ICC) were calculated to assess interrater reliability. RESULTS: No significant differences were ascertained for femoral (p = 0.330), tibial (p = 0.177), and overall leg rotation measurements (p = 0.358) among high-quality, low-dose, and ultra-low-dose protocols. Interrater reliability was excellent for torsion of the femur (ICC 0.915, 95% confidence interval 0.871-0.947), tibia (0.960, 0.938-0.976), and overall leg (0.967, 0.945-0.981). In specimens with total knee endoprostheses, absolute rotational measurements were unaffected by dose level and tube voltage despite superior diagnostic confidence on the ipsilateral and contralateral sides with modified settings (p < 0.001). CONCLUSIONS: Combining the advantages of photon-counting CT and spectral shaping, reliable leg torsion analyses are feasible with ultra-low radiation exposure even in the presence of total knee endoprostheses.

MRI-Based Evaluation of the Flexor Digitorum Superficialis Anatomy: Investigating the Prevalence and Morphometry of the "Chiasma Antebrachii".

Recent dissection studies resulted in the introduction of the term "chiasma antebrachii", which represents an intersection of the flexor digitorum superficialis (FDS) tendons for digits 2 and 3 in the distal third of the forearm. This retrospective investigation aimed to provide an MRI-based morphologic analysis of the chiasma antebrachii. In 89 patients (41 women, 39.3 ± 21.3 years), MRI examinations of the forearm (2010-2021) were reviewed by two radiologists, who evaluated all studies for the presence and length of the chiasma as well as its distance from the distal radioulnar and elbow joint. The chiasma antebrachii was identified in the distal third of the forearm in 88 patients (98.9%), while one intersection was located more proximally in the middle part. The chiasma had a median length of 28 mm (interquartile range: 24-35 mm). Its distances to the distal radioulnar and elbow joint were 16 mm (8-25 mm) and 215 mm (187-227 mm), respectively. T1-weighted post-contrast sequences were found to be superior to T2- or proton-density-weighted sequences in 71 cases (79.8%). To conclude, the chiasma antebrachii is part of the standard FDS anatomy. Knowledge of its morphology is important, e.g., in targeted injections of therapeutics or reconstructive surgery.

Artificial-intelligence-enhanced synthetic thick slabs versus standard slices in digital breast tomosynthesis.

OBJECTIVES: Digital breast tomosynthesis (DBT) can provide additional information over mammography, albeit at the cost of prolonged reading time. This study retrospectively investigated the impact of reading enhanced synthetic 6 mm slabs instead of standard 1 mm slices on interpretation time and readers performance in a diagnostic assessment centre. METHODS: Three radiologists (R1-3; 6/4/2 years of breast imaging experience) reviewed 111 diagnostic DBT examinations. Two datasets were interpreted independently for each patient, with one set containing artificial-intelligence-enhanced synthetic 6 mm slabs with 3 mm overlap, while the other set comprised standard 1 mm slices. Blinded to histology and follow-up, readers noted individual BIRADS categories and diagnostic confidence while reading time was recorded. Among the 111 examinations, 70 findings were histopathologically correlated including 56 malignancies. RESULTS: No significant difference was found between BIRADS categories assigned based on 6 mm vs 1 mm datasets (p ≥ 0.317). Diagnostic accuracy was comparable for 6 mm and 1 mm readings (R1: 87.0% vs 87.0%; R2: 86.1% vs 87.0%; R3: 80.0% vs 84.4%; p ≥ 0.125) with high interrater agreement (intraclass correlation coefficient 0.848 vs 0.865). One reader reported higher confidence with 1 mm slices (R1: p = 0.033). Reading time was substantially shorter when interpreting 6 mm slabs compared to 1 mm slices (R1: 33.5 vs 46.2; R2: 49.1 vs 64.8; R3: 39.5 vs 67.2 sec; all p < 0.001). CONCLUSIONS: Artificial-intelligence-enhanced synthetic 6 mm slabs allow for substantial interpretation time reduction in diagnostic DBT without a decrease in reader accuracy. ADVANCES IN KNOWLEDGE: A simplified slab-only protocol instead of 1 mm slices may offset the higher reading time without a loss of diagnosis-relevant image information in first and second readings. Further evaluations are required regarding workflow implications, particularly in screening settings.

Ultrahigh-resolution computed tomography of the cervical spine without dose penalty employing a cadmium-telluride photon-counting detector.

PURPOSE: This cadaveric study compared image quality between a third-generation dual-source CT scanner with energy-integrating detector technology (EID) and a first-generation CT system employing a photon-counting detector (PCD) for the cervical spine in ultrahigh-resolution mode. METHODS: The cervical spine of eight formalin-fixed full-body cadaveric specimens was scanned with both CT systems using 140 kVp scan protocols matched for CTDIvol (full-dose; low-dose; ultralow-dose; 10 mGy; 3 mGy; 1 mGy). Images were reconstructed with 1 mm slice thickness and 0.5 mm increment. Three radiologists rated overall subjective image quality based on an equidistant five-point scale with the intraclass correlation coefficient (ICC) calculated for assessment of interobserver reliability. Contrast-to-noise ratios were calculated individually for bone (CNRbone) and muscle tissue (CNRmuscle) to provide objective criteria of image analysis. RESULTS: Subjective image quality, as well as CNRbone, and CNRmuscle were each superior for PCD-CT compared to EID-CT among dose-matched scan protocol pairs (all p < 0.05). Between full-dose EID-CT and low-dose PCD-CT, subjective image quality was equal (p = 0.903), while superior quantitative results regarding the latter were ascertained (both p < 0.001). Similarly, objective analysis determined higher CNRbone, and CNRmuscle in ultralow-dose PCD-CT compared to low-dose EID-CT (both p < 0.001), while readers considered the image quality of the respective studies comparable (p > 0.99). Interobserver reliability was good, denoted by an ICC of 0.861 (95 % confidence interval: 0.788 - 0.914; p < 0.001). CONCLUSIONS: In cervical spine examinations, both subjective and objective image quality of PCD-CT were superior to EID-CT in comparison of scan protocols with corresponding dose levels, suggesting potential for significantly reducing the radiation exposure without compromising image quality.

Twin Robotic Gantry-Free Cone-Beam CT in Acute Elbow Trauma.

Background Posttraumatic CT imaging of the elbow can be challenging when patient mobility is limited. Gantry-free cone-beam CT (CBCT) with a twin robotic radiography system offers greater degrees of positioning freedom for three-dimensional elbow scans over gantry-based multidetector CT (MDCT), but studies analyzing their clinical value remain lacking. Purpose To investigate the diagnostic performance of gantry-free CBCT versus two-dimensional radiography in adults and children with acute elbow trauma. Materials and Methods In a retrospective study, consecutive patients with elbow trauma and positioning difficulty in a gantry-based MDCT who underwent three-dimensional elbow imaging with a gantry-free CBCT after radiography were enrolled between January 2021 and April 2022 at a tertiary care university hospital. Imaging data sets were independently analyzed for fracture presence, articular involvement, and multi-fragment injuries by three radiologists. Diagnostic performance was calculated individually with surgical reports serving as the reference standard. Differences between radiography and CBCT were compared with the McNemar test. Diagnostic confidence was estimated subjectively by each reader, and results were compared with the Wilcoxon signed-rank test. Results Elbow examinations of 23 adults and children (mean age ± SD, 49 years ± 23; seven women) were included with individual assessment of humerus, radius, and ulna (69 bones; 36 fractured). Multi-fragmentary fracture patterns and involvement of articular surfaces were ascertained in 28 and 30 bones, respectively. CBCT allowed for similar or higher sensitivity compared with radiography in the assessment of fractures (range for three readers, 94%-100% vs 72%-81%; respectively, P ≤ .06-.008), articular surface involvement (90%-97% vs 73%-87%; P ≤ .25), and multi-fragmentary patterns (96%-96% vs 68%-75%; P ≤ .03). Readers' diagnostic confidence improved considerably with access to CBCT data sets versus radiographs (all P ≤ .001). For CBCT, the median dose-length product was 70.9 mGy · cm, and the volume CT dose index was 4.4 mGy. Conclusion In acute elbow injuries, gantry-free cone-beam CT enabled improved detection of fractures, articular involvement, and multi-fragmentary patterns compared with two-dimensional radiography. Published under a CC BY 4.0 license Online supplemental material is available for this article.

Accuracy of pedicle screw placement using neuronavigation based on intraoperative 3D rotational fluoroscopy in the thoracic and lumbar spine.

INTRODUCTION: In spinal surgery, precise instrumentation is essential. This study aims to evaluate the accuracy of navigated, O-arm-controlled screw positioning in thoracic and lumbar spine instabilities. MATERIALS AND METHODS: Posterior instrumentation procedures between 2010 and 2015 were retrospectively analyzed. Pedicle screws were placed using 3D rotational fluoroscopy and neuronavigation. Accuracy of screw placement was assessed using a 6-grade scoring system. In addition, screw length was analyzed in relation to the vertebral body diameter. Intra- and postoperative revision rates were recorded. RESULTS: Thoracic and lumbar spine surgery was performed in 285 patients. Of 1704 pedicle screws, 1621 (95.1%) showed excellent positioning in 3D rotational fluoroscopy imaging. The lateral rim of either pedicle or vertebral body was protruded in 25 (1.5%) and 28 screws (1.6%), while the midline of the vertebral body was crossed in 8 screws (0.5%). Furthermore, 11 screws each (0.6%) fulfilled the criteria of full lateral and medial displacement. The median relative screw length was 92.6%. Intraoperative revision resulted in excellent positioning in 58 of 71 screws. Follow-up surgery due to missed primary malposition had to be performed for two screws in the same patient. Postsurgical symptom relief was reported in 82.1% of patients, whereas neurological deterioration occurred in 8.9% of cases with neurological follow-up. CONCLUSIONS: Combination of neuronavigation and 3D rotational fluoroscopy control ensures excellent accuracy in pedicle screw positioning. As misplaced screws can be detected reliably and revised intraoperatively, repeated surgery for screw malposition is rarely required.

Metal artifact reduction in ultra-high-resolution cone-beam CT imaging with a twin robotic X-ray system.

Cone-beam computed tomography (CBCT) has been shown to be a powerful tool for 3D imaging of the appendicular skeleton, allowing for detailed visualization of bone microarchitecture. This study was designed to compare artifacts in the presence of osteosynthetic implants between CBCT and multidetector computed tomography (MDCT) in cadaveric wrist scans. A total of 32 scan protocols with varying tube potential and current were employed: both conventional CBCT and MDCT studies were included with tube voltage ranging from 60 to 140 kVp as well as additional MDCT protocols with dedicated spectral shaping via tin prefiltration. Irrespective of scanner type, all examinations were conducted in ultra-high-resolution (UHR) scan mode. For reconstruction of UHR-CBCT scans an additional iterative metal artifact reduction algorithm was employed, an image correction tool which cannot be used in combination with UHR-MDCT. To compare applied radiation doses between both scanners, the volume computed tomography dose index for a 16 cm phantom (CTDIvol) was evaluated. Images were assessed regarding subjective and objective image quality. Without automatic tube current modulation or tube potential control, radiation doses ranged between 1.3 mGy (with 70 kVp and 50.0 effective mAs) and 75.2 mGy (with 140 kVp and 383.0 effective mAs) in UHR-MDCT. Using the pulsed image acquisition method of the CBCT scanner, CTDIvol ranged between 2.3 mGy (with 60 kVp and 0.6 mean mAs per pulse) and 61.0 mGy (with 133 kVp and 2.5 mean mAs per pulse). In essence, all UHR-CBCT protocols employing a tube potential of 80 kVp or more were found to provide superior overall image quality and artifact reduction compared to UHR-MDCT (all p < .050). Interrater reliability of seven radiologists regarding image quality was substantial for tissue assessment and moderate for artifact assessment with Fleiss kappa of 0.652 (95% confidence interval 0.618-0.686; p < 0.001) and 0.570 (95% confidence interval 0.535-0.606; p < 0.001), respectively. Our results demonstrate that the UHR-CBCT scan mode of a twin robotic X-ray system facilitates excellent visualization of the appendicular skeleton in the presence of metal implants. Achievable image quality and artifact reduction are superior to dose-comparable UHR-MDCT and even MDCT protocols employing spectral shaping with tin prefiltration do not achieve the same level of artifact reduction in adjacent soft tissue.

Can the MRI based AMADEUS score accurately assess pre-surgery chondral defect severity according to the ICRS arthroscopic classification system?

PURPOSE: The AMADEUS (Area Measurement And DEpth and Underlying Structures) scoring and grading system has been proposed for the MRI based evaluation of untreated focal chondral defects around the knee. The clinical practicability, its correlation with arthroscopically assessed grading systems (ICRS - International Cartilage Repair Society) and thereby its clinical value in terms of decision making and guiding prognosis was yet to determine. METHODS: From 2008 to 2019 a total of 89 individuals were indicated for high tibial valgus osteotomy (HTO) due to tibial varus deformity and concomitant chondral defects of the medial compartment of the knee. All patients received a preoperative MRI (1.5 Tesla or 3.0 Tesla) and pre-osteotomy diagnostic arthroscopy. Chondral defects of the medial compartment were scored and graded with the MRI based AMADEUS by three independent raters and compared to arthroscopic defect grading by the ICRS system. Interrater and intrarater reliability as well as correlation analysis with the ICRS classification system were assessed. RESULTS: Intraclass correlation coefficients for the various subscores of the AMADEUS showed an overall good to excellent interrater agreement (min: 0.26, max: 0.80). Intrarater agreement turned out to be substantially inferior (min: 0.08, max: 0.53). Spearman correlation revealed an overall moderate correlative association of the AMADEUS subscores with the ICRS classification system, apart from the defect area subscore. Sensitivity of the AMADEUS to accurately identify defect severity according to the ICRS was 0.7 (0.69 for 3.0 Tesla MRI, 0.67 for 1.5 Tesla MRI). The mean AMADEUS grade was 2.60 ± 0.81 and the mean ICRS score 2.90 ± 0.63. CONCLUSIONS: Overall, the AMADEUS with all its subscores shows moderate correlation with the arthroscopic chondral grading system according to ICRS. This suggests that chondral defect grading by means of the MRI based AMADEUS is well capable of influencing and guiding treatment decisions. Interrater reliability shows overall good agreement.

Dose reduction potential in cone-beam CT imaging of upper extremity joints with a twin robotic x-ray system.

Cone-beam computed tomography is a powerful tool for 3D imaging of the appendicular skeleton, facilitating detailed visualization of bone microarchitecture. This study evaluated various combinations of acquisition and reconstruction parameters for the cone-beam CT mode of a twin robotic x-ray system in cadaveric wrist and elbow scans, aiming to define the best possible trade-off between image quality and radiation dose. Images were acquired with different combinations of tube voltage and tube current-time product, resulting in five scan protocols with varying volume CT dose indices: full-dose (FD; 17.4 mGy), low-dose (LD; 4.5 mGy), ultra-low-dose (ULD; 1.15 mGy), modulated low-dose (mLD; 0.6 mGy) and modulated ultra-low-dose (mULD; 0.29 mGy). Each set of projection data was reconstructed with three convolution kernels (very sharp [Ur77], sharp [Br69], intermediate [Br62]). Five radiologists subjectively assessed the image quality of cortical bone, cancellous bone and soft tissue using seven-point scales. Irrespective of the reconstruction kernel, overall image quality of every FD, LD and ULD scan was deemed suitable for diagnostic use in contrast to mLD (very sharp/sharp/intermediate: 60/55/70%) and mULD (0/3/5%). Superior depiction of cortical and cancellous bone was achieved in FDUr77 and LDUr77 examinations (p < 0.001) with LDUr77 scans also providing favorable bone visualization compared to FDBr69 and FDBr62 (p < 0.001). Fleiss' kappa was 0.618 (0.594-0.641; p < 0.001), indicating substantial interrater reliability. In this study, we demonstrate that considerable dose reduction can be realized while maintaining diagnostic image quality in upper extremity joint scans with the cone-beam CT mode of a twin robotic x-ray system. Application of sharper convolution kernels for image reconstruction facilitates superior display of bone microarchitecture.

Contrast-enhanced MRI of the wrist: Intravenous application of gadolinium improves diagnosis in ulnar-sided injuries of the TFCC.

PURPOSE: Although lesions of the triangular fibrocartilage complex (TFCC) frequently induce ulnar-sided wrist pain and potentially distal radioulnar joint instability, diagnosis can pose a challenge due to the intricate anatomy. This study aims to evaluate the benefits of contrast-enhanced sequences for the detection of TFCC injuries in magnetic resonance imaging of the wrist. METHOD: 94 patients underwent wrist MRI with intravenous application of gadolinium-based contrast agents. For each patient, two datasets were analysed independently by two board-certified radiologists: One set comprised only plain T1- and fat-saturated proton-density-weighted sequences, while the second dataset included contrast-enhanced T1-weighted images with fat suppression. Arthroscopy or clinical reports served as reference standard with the former being used whenever available. Diagnostic confidence and TFCC component assessability were subjectively evaluated. Contrast-to-noise ratios (CNR) were calculated serve as an objective indicator of image contrast. RESULTS: Lesions of the articular disc, the foveal and styloid ulnar attachment were present in 24 (25.5%), 61 (64.9%) and 53 (56.4%) patients. Access to contrast-enhanced T1 images improved the diagnostic accuracy for injuries of the styloid (R1/R2, 0.68/0.73 vs. 0.86/0.88) and foveal attachment (0.68/0.72 vs. 0.90/0.89) substantially compared to plain MRI (all p < 0.001), while no benefits could be identified for lesions of the central disc (0.89/0.90 vs. 0.87/0.90). Readers' diagnostic confidence and CNR for ulnar-sided lesions improved with contrast-enhanced T1 sequences available (p < 0.001). CONCLUSIONS: With superior CNR in lesions of the TFCC's foveal and styloid attachment, contrast-enhanced, fat-saturated T1-weighted sequences facilitate higher diagnostic accuracy and confidence than fat-saturated PD- and plain T1-weighted MRI.