Metal artifact reduction in computed tomography: Is it of benefit in evaluating sacroiliac joint fusion?

PURPOSE: The aim of this study was to compare image quality of computed tomography (CT) images with and without orthopedic metal artifact reduction (O-MAR) in the follow-up of patients after sacroiliac (SI) joint fusion. METHODS: Thirty-six consecutive patients (31 females and 5 males) undergoing CT within 24 h after SI joint fusion were included. CT images were reconstructed with and without O-MAR and scored by two radiologists with over 20 years of experience using a six-point ordinal scale. Images were scored on overall image quality and five criteria that are important to the clinician for the follow-up of patients after SI joint fusion. In addition, images were scored on how well four bony structures could be delineated. Wilcoxon signed-ranks tests with Holm-Bonferroni correction were used to test for differences between the radiologists' scores on CT images with and without O-MAR. RESULTS: Both radiologists scored overall image quality significantly higher (p < 0.05) on the images without O-MAR than on the images with O-MAR. In addition, two of the follow-up criteria, delineation of the sacrum and delineation of the implanted ilium were scored significantly higher (p < 0.05) on the images without O-MAR. Neither radiologist scored the images with O-MAR significantly higher than the images without O-MAR for any of the criteria. CONCLUSION: CT imaging without O-MAR provided higher image quality and better assessment of SI joint fusion follow-up criteria compared to CT imaging with O-MAR in the follow-up of patients after SI joint fusion.

Lessons learned during implementation of MR-guided High-Intensity Focused Ultrasound treatment of uterine fibroids.

BACKGROUND: Although promising results have been reported for Magnetic Resonance image-guided High-Intensity Focused Ultrasound (MR-HIFU) treatment of uterine fibroids, this treatment is not yet widely implemented in clinical practice. During the implementation of a new technology, lessons are learned and an institutional learning-curve often has to be completed. The primary aim of our prospective cohort study was to characterize our learning-curve based on our clinical outcomes. Secondary aims included identifying our lessons learned during implementation of MR-HIFU on a technical, patient selection, patient counseling, medical specialists and organizational level. RESULTS: Our first seventy patients showed significant symptom reduction and improvement of quality of life at 3, 6 and 12 months after MR-HIFU treatment compared to baseline. After the first 25 cases, a clear plateau phase was reached in terms of failed treatments. The median non-perfused volume percentage of these first 25 treatments was 44.6% (range: 0-99.7), compared to a median of 74.7% (range: 0-120.6) for the subsequent treatments. CONCLUSIONS: Our findings describe the learning-curve during the implementation of MR-HIFU and include straightforward suggestions to shorten learning-curves for future users. Moreover, the lessons we learned on technique, patient selection, patient counseling, medical specialists and organization, together with the provided supplements, may be of benefit to other institutions aiming to implement MR-HIFU treatment of uterine fibroids. Trial registration ISRCTN14634593. Registered January 12, 2021-Retrospectively registered, https://www.isrctn.com/ISRCTN14634593 .

Optimization of pulmonary emphysema quantification on CT scans of COPD patients using hybrid iterative and post processing techniques: correlation with pulmonary function tests.

OBJECTIVES: The aim of this study was to assess the effect of hybrid iterative reconstruction and post processing on emphysema quantification in low-dose CT scans of COPD patients using pulmonary function tests (PFT) as a reference. METHODS: CT scans of 23 COPD patients diagnosed with GOLD I or higher were reconstructed with iDose4 level 1 to 7 in IntelliSpace Portal (ISP) 6 and 7. ISP7 was used with and without specific denoising filter for COPD. The extent of emphysema was measured as percentage of lung voxels with attenuation < - 950 Hounsfield units (%LAA-950). The correlation between %LAA-950 and PFT, age, BMI, pack years, and the Clinical COPD Questionnaire (CCQ) and Medical Research Council dyspnea scale (MRC) was determined. RESULTS: Denoising significantly reduced %LAA-950 as was demonstrated by lower %LAA-950 in ISP7 with denoising filter and a significant reduction in %LAA-950 with higher iDose4 levels. All PFT except forced vital capacity (FVC) were significantly inversely correlated with %LAA-950. There was a trend toward a stronger correlation at higher iDose4 levels. %LAA-950 was also significantly correlated with BMI, GOLD class, and CCQ scores. CONCLUSIONS: Our study showed that hybrid iterative reconstruction and use of post processing denoising can optimize the use of emphysema quantification in CT scans as a complimentary diagnostic tool to stage COPD in addition to PFT.

KCa2 channels activation prevents [Ca2+]i deregulation and reduces neuronal death following glutamate toxicity and cerebral ischemia.

Exacerbated activation of glutamate receptor-coupled calcium channels and subsequent increase in intracellular calcium ([Ca2+]i) are established hallmarks of neuronal cell death in acute and chronic neurological diseases. Here we show that pathological [Ca2+]i deregulation occurring after glutamate receptor stimulation is effectively modulated by small conductance calcium-activated potassium (KCa2) channels. We found that neuronal excitotoxicity was associated with a rapid downregulation of KCa2.2 channels within 3 h after the onset of glutamate exposure. Activation of KCa2 channels preserved KCa2 expression and significantly reduced pathological increases in [Ca2+]i providing robust neuroprotection in vitro and in vivo. These data suggest a critical role for KCa2 channels in excitotoxic neuronal cell death and propose their activation as potential therapeutic strategy for the treatment of acute and chronic neurodegenerative disorders.