A New Iterative Metal Artifact Reduction Algorithm for Both Energy-Integrating and Photon-Counting CT Systems.

OBJECTIVES: The aim of this study was to introduce and evaluate a new metal artifact reduction framework (iMARv2) that addresses the drawbacks (residual artifacts after correction and user preferences for image quality) associated with the current clinically applied iMAR. MATERIALS AND METHODS: A new iMARv2 has been introduced, combining the current iMAR with new modular components to remove residual metal artifacts after image correction. The postcorrection image impression is adjustable with user-selectable strength settings. Phantom scans from an energy-integrating and a photon-counting detector CT were used to assess image quality, including a Gammex phantom and anthropomorphic phantoms. In addition, 36 clinical cases (with metallic implants such as dental fillings, hip replacements, and spinal screws) were reconstructed and evaluated in a blinded and randomized reader study. RESULTS: The Gammex phantom showed lower HU errors compared with the uncorrected image at almost all iMAR and iMARv2 settings evaluated, with only minor differences between iMAR and the different iMARv2 settings. In addition, the anthropomorphic phantoms showed a trend toward lower errors with higher iMARv2 strength settings. On average, the iMARv2 strength 3 performed best of all the clinical reconstructions evaluated, with a significant increase in diagnostic confidence and decrease in artifacts. All hip and dental cases showed a significant increase in diagnostic confidence and decrease in artifact strength, and the improvements from iMARv2 in the dental cases were significant compared with iMAR. There were no significant improvements in the spine. CONCLUSIONS: This work has introduced and evaluated a new method for metal artifact reduction and demonstrated its utility in routine clinical datasets. The greatest improvements were seen in dental fillings, where iMARv2 significantly improved image quality compared with conventional iMAR.

Shoulder complaints and incidence of shoulder pathologies after contralateral major amputation in the mid and long-term.

INTRODUCTION: Amputations of the upper extremity are rare but present a life-altering event that is accompanied with considerable restrictions for the affected patients. Even with functional prosthesis, tasks of the amputated limb are usually transferred to the unaffected arm which could result in complaints of the unaffected shoulder in the mid and long term. We therefore aimed to investigate musculoskeletal pain and morphological degenerative changes of the shoulder following a contralateral amputation. MATERIALS AND METHODS: We included all patients with a major amputation treated at our institution with a minimum of three years since the amputation. All patients received an MRI of both shoulders and were investigated using validated scores for the upper extremity and physical activity (SSV, ASES, DASH, GPAQ, SF-36). Results of the MRIs were investigated for morphological changes by two blinded investigators comparing the side of the amputation and the unharmed upper extremity and results were correlated to the time since amputation and their physical activity. RESULTS: A total of 20 patients with a mean age of 56 ± 19.9 years (range, 23-82 years) could be included in the study. The mean time since the amputation was 26.3 ± 19 years (range, 3-73 years). On the unharmed upper extremity, the mean SSV was 61.9 ± 24.6, the mean ASES-Score 54.5 ± 20.3, the Constant-score of 63.7 ± 40.4 and a DASH-score of 47.6 ± 23.8. The MRI of the unharmed shoulder showed significant more full-thickness rotator cuff tears and joint effusion compared to the side of the amputation. Significant differences in the degree of a glenohumeral arthritis, AC-joint arthritis, or partial rotator cuff tears could not be found between shoulders. CONCLUSION: Amputations of the upper extremity are associated with a high disability of the unharmed upper extremity and more full thickness rotator cuff tears compared to the side of the amputation. However, the small number of patients and rotator cuff injuries should be kept in mind when interpreting the data. LEVEL OF EVIDENCE: IV (retrospective case series).

[Video-based treatment in psychodynamic psychotherapy in times of the COVID-19 pandemic]. / Videobasierte Behandlungen in der psychodynamischen Psychotherapie in Zeiten der COVID-19-Pandemie: Interviewstudie mit Psychotherapeut*innen und Patient*innen.

BACKGROUND: In the course of the pandemic triggered by the coronavirus disease 2019 (COVID-19), video-based treatment (VBT) has undergone a trend reversal. It must be assumed that the abrupt switch from traditional psychotherapy to the video setting (VS) has an impact on the therapeutic relationship and thus on the therapeutic process. This study examined how the switch from traditional treatment to VBT (and back again) during the COVID-19 pandemic was experienced by patients and therapists with respect to the therapeutic relationship and the therapeutic process. METHODS: Group-specific, semi-structured interviews with therapists (n = 8), therapists in training (n = 6), and patients (n = 9). RESULTS: The results show that the majority of participants, both therapists as well as patients, experienced the therapeutic situation in VS as more permeable and less predictable. Although the VS contributes to maintenance of the therapeutic situation, the interaction was described as shallow and less oriented. Furthermore, every setting change was associated with a process of habituation. Therefore, the therapeutic work can only be carried out with the highest possible intensity after several sessions within each setting. CONCLUSION: The possibility of maintaining the therapeutic relationship using VBT can lead to a strengthening of the therapeutic alliance. Although the VS is associated with uncertainties, shame-ridden topics can be addressed more freely. Anxiety patients, in particular, could engage in a more intense therapeutic process after a universally observed phase of habituation.