AimsAim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure.Methods and resultsWe performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0–0.08 vs. 8.87 mSv, iqr 3.67–22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0–12 vs. 859 s, iqr 545–1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs.ConclusionThis is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy.Trial registrationclinicaltrials.gov Identifier: NCT01132274.

The findings indicate that sequences are suitable for quantitative in vivo assessment of articular cartilage at 3 T. Magn Reson Med 77:1265-1275, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

21Purpose. To investigate the association of quantitative MRI (qMRI) parameters with 22 arthroscopic grading of cartilage degeneration. Arthroscopy of the knee is considered to be the 23 gold standard of OA diagnostics, however, it is operator-dependent and limited to the evaluation 24 of the articular surface. qMRI provides information on the quality of articular cartilage and its 25 changes even at early stages of a disease.

2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:678-689.

In this study, the rabbit model with anterior cruciate ligament transection (ACLT) was used to investigate early degenerative changes in cartilage using multiparametric quantitative magnetic resonance imaging (qMRI). ACLT was surgically induced in the knees of skeletally mature New Zealand White rabbits (n = 14). ACL transected and contralateral knee compartments—medial femur, lateral femur, medial tibia, and lateral tibia—were harvested 2 (n = 8) and 8 weeks (n = 6) postsurgery. Twelve age‐matched nonoperated rabbits served as control. qMRI was conducted at 9.4 T and included relaxation times T1, T2, continuous‐wave T1ρ (CWT1ρ), adiabatic T1ρ (AdT1ρ), adiabatic T2ρ (AdT2ρ), and relaxation along a fictitious field (TRAFF). For reference, quantitative histology and biomechanical measurements were carried out. Posttraumatic changes were primarily noted in the superficial half of the cartilage. Prolonged T1, T2, CWT1ρ, and AdT1ρ were observed in the lateral femur 2 and 8 weeks post‐ACLT, compared with the corresponding control and contralateral groups (P < .05). Collagen orientation was significantly altered in the lateral femur at 2 weeks post‐ACLT compared with the corresponding control group. In the medial femur, all the studied relaxation time parameters, except TRAFF, were increased 8 weeks post‐ACLT, as compared with the corresponding contralateral and control groups (P < .05). Similarly, significant proteoglycan loss was observed in the medial femur at 8 weeks following surgery (P < .05). Multiparametric MRI demonstrated early degenerative changes primarily in the superficial cartilage with T1, T2, CWT1ρ, and AdT1ρ sensitive to cartilage changes at 2 weeks after surgery.

Chondral lesions lead to degenerative changes in the surrounding cartilage tissue, increasing the risk of developing post-traumatic osteoarthritis (PTOA). This study aimed to investigate the feasibility of quantitative magnetic resonance imaging (qMRI) for evaluation of articular cartilage in PTOA. Articular explants containing surgically induced and repaired chondral lesions were obtained from the stifle joints of seven Shetland ponies (14 samples). Three age-matched nonoperated ponies served as controls (six samples). The samples were imaged at 9.4 T. The measured qMRI parameters included T 1 , T 2 , continuous-wave T 1ρ (CWT 1ρ), adiabatic T 1ρ (AdT 1ρ), and T 2ρ (AdT 2ρ) and relaxation along a fictitious field (T RAFF). For reference, cartilage equilibrium and dynamic moduli, proteoglycan content and collagen fiber orientation were determined. Mean values and profiles from full-thickness cartilage regions of interest, at increasing distances from the lesions, were used to compare experimental against control and to correlate qMRI with the references. Significant alterations were detected by qMRI parameters, including prolonged T 1 , CWT 1ρ , and AdT 1ρ in the regions adjacent to the lesions. The changes were confirmed by the reference methods. CWT 1ρ was more strongly associated with the reference measurements and prolonged in the affected regions at lower spin-locking amplitudes. Moderate to strong correlations were found between all qMRI parameters and the reference parameters (ρ = −0.531 to −0.757). T 1 , low spin-lock amplitude CWT 1ρ , and AdT 1ρ were most responsive to changes in visually intact cartilage adjacent to the lesions. In the context of PTOA, these findings highlight the potential of T 1 , CWT 1ρ , and AdT 1ρ in evaluation of compositional and structural changes in cartilage.

Purpose: To provide a narrative review of the most relevant original research published in 2017/2018 on osteoarthritis imaging. Methods: The PubMed database was used to recover all relevant articles pertaining to osteoarthritis and medical imaging published between 1 April 2017 and 31 March 2018. Review articles, case studies and in vitro or animal studies were excluded. The original publications were subjectively sorted based on relevance, novelty and impact. Results and conclusions: The publication search yielded 1,155 references. In the assessed publications, the most common imaging modalities were radiography (N ¼ 708) and magnetic resonance imaging (MRI) (355), followed by computed tomography (CT) (220), ultrasound (85) and nuclear medicine (17). An overview of the most important publications to the osteoarthritis (OA) research community is presented in this narrative review. Imaging studies play an increasingly important role in OA research, and have helped us to understand better the pathophysiology of OA. Radiography and MRI continue to be the most applied imaging modalities, while quantitative MRI methods and texture analysis are becoming more popular. The value of ultrasound in OA research has been demonstrated. Several multi-modality predictive models have been developed. Deep learning has potential for more automatic and standardized analyses in future OA imaging research.

AdT and AdT measurements have the potential to identify changes in structural composition of meniscus tissue associated with meniscal tear and cartilage loss in a cohort group of mild OA patients and asymptomatic volunteers.