Deep learning-based quantification of osteonecrosis using magnetic resonance images in Gaucher disease.

Gaucher disease is one of the most common lysosomal storage disorders. Osteonecrosis is a principal clinical manifestation of Gaucher disease and often leads to joint collapse and fractures. T1-weighted (T1w) modality in MRI is widely used to monitor bone involvement in Gaucher disease and to diagnose osteonecrosis. However, objective and quantitative methods for characterizing osteonecrosis are still limited. In this work, we present a deep learning-based quantification approach for the segmentation of osteonecrosis and the extraction of characteristic parameters. We first constructed two independent U-net models to segment the osteonecrosis and bone marrow unaffected by osteonecrosis (UBM) in spine and femur respectively, based on T1w images from patients in the UK national Gaucherite study database. We manually delineated parcellation maps including osteonecrosis and UBM from 364 T1w images (176 for spine, 188 for femur) as the training datasets, and the trained models were subsequently applied to all the 917 T1w images in the database. To quantify the segmentation, we calculated morphological parameters including the volume of osteonecrosis, the volume of UBM, and the fraction of total marrow occupied by osteonecrosis. Then, we examined the correlation between calculated features and the bone marrow burden score for marrow infiltration of the corresponding image, and no strong correlation was found. In addition, we analyzed the influence of splenectomy and the interval between the age at first symptom and the age of onset of treatment on the quantitative measurements of osteonecrosis. The results are consistent with previous studies, showing that prior splenectomy is closely associated with the fractional volume of osteonecrosis, and there is a positive relationship between the duration of untreated disease and the quantifications of osteonecrosis. We propose this technique as an efficient and reliable tool for assessing the extent of osteonecrosis in MR images of patients and improving prediction of clinically important adverse events.

Incidence and distribution of injuries associated with e-scooter use: a radiological perspective.

OBJECTIVES: To investigate electric scooter (e-scooter)-associated radiological injury incidence and distribution of injuries. METHODS: Retrospective cross-sectional study of radiological examinations related to e-scooter injuries at a major trauma centre in a small university city. The hospital radiology information system was searched for terms related to e-scooters between January 1, 2015, and October 31, 2022. E-scooter use was confirmed by review of the patients' electronic medical records. Specific injuries were divided based on site of injury using the Injury Severity Scale categorized groups. RESULTS: A total of 568 radiological studies related to e-scooter injuries were identified on 340 distinct patients (56% male, with an average age of 28 years). Peak incidence of e-scooter-related injuries was seen in the summer months, after a local scooter sharing system was introduced in October 2020. A total of 149 patients had radiologically diagnosed injuries, with extremity injuries being most frequent (80%). Facial (8%), head/neck (8%), and thorax/abdomen (4%) were less common. Radial head fractures were the most common injury (n = 27). Thirteen patients had multiple sites of injury, four of which had both upper limb and facial bone fractures described. CONCLUSIONS: We report a significant increase in radiological investigations and injuries in the context of e-scooter injuries, particularly since the introduction of an e-scooter sharing scheme. This study informs radiologists on common locations of injuries when reporting studies of patients that have had e-scooter-related injuries. ADVANCES IN KNOWLEDGE: This is the first UK-based study providing a comprehensive radiological perspective of the impact of e-scooter use and associated distribution of injuries, adding important data for many cities that are currently undertaking review of their e-scooter sharing schemes.

Recent developments in advanced imaging in gout.

The plain radiographic features of gout are well known; however, the sensitivity of plain radiographs alone for the detection of signs of gout is poor in acute disease. Radiographic abnormalities do not manifest until late in the disease process, after significant joint and soft tissue damage has already occurred. The advent of dual-energy computed tomography (DECT) has enabled the non-invasive diagnosis and quantification of gout by accurately confirming the presence and extent of urate crystals in joints and soft tissues, without the need for painful and often unreliable soft tissue biopsy or joint aspiration. Specific ultrasound findings have been identified and may also be used to aid diagnosis. Both ultrasound and magnetic resonance imaging (MRI) may be used for the measurement of disease extent, monitoring of disease activity or treatment response, although MRI findings are nonspecific. In this article we summarize the imaging findings and diagnostic utility of plain radiographs, ultrasound, DECT, MRI and nuclear medicine studies in the assessment as well as the implications and utility these tools have for measuring disease burden and therapeutic response.

Neck or groin access for varicocele embolisation: Is it important?

INTRODUCTION: Varicocele embolisation is an excellent treatment option for symptomatic scrotal varicosities. The purpose of this study was to assess the current practice of the endovascular treatment of left-sided varicoceles at our institution, to compare the findings to international standards and to identify which access site reduces screening time and radiation dose. METHODS: All left-sided varicocele embolisations over a 4-year period were identified and analysed with regards to technical success, complications and recurrence rates. The results were analysed with regard to the encountered anatomy on a case-to-case basis to identify anatomical factors influencing the outcome of the procedure. RESULTS: During the study period 95 primary left-sided varicocele embolisations were performed by two experienced consultants. Five cases had a normal initial venogram (Type 0) and further five had unsuitable anatomy for embolisation. Eighty-three of the remaining 85 attempted embolisations were technically successful (98% technical success rate). The clinical success rate was determined by recurrence, which was documented in five cases (mean follow-up 34.3 month, 6% recurrence rate). Recurrence was associated with more complex local anatomy (Type 3 and Type 4). The overall findings were consistent with international published standards for technical success rate (95-100%) and recurrence rates (1.6-10%). Complication rates were low with extravasation being reported in 4.7% (all self-limiting) and temporary pain in 3.5% of the cases. There was no significant difference in radiation dose/screening time, success or complications when comparing a groin versus neck approach to the embolisation procedure (P > 0.05). CONCLUSIONS: Varicocele embolisation is successful with a low complications rate. Neck and groin access are equally successful with no significant difference in screening time.

DNA sequence- and conformation-directed positioning of nucleosomes by chromatin-remodeling complexes.

Chromatin-remodeling complexes can translocate nucleosomes along the DNA in an ATP-coupled reaction. This process is an important regulator of all DNA-dependent processes because it determines whether certain DNA sequences are found in regions between nucleosomes with increased accessibility for other factors or wrapped around the histone octamer complex. In a comparison of seven different chromatin-remodeling machines (ACF, ISWI, Snf2H, Chd1, Mi-2, Brg1, and NURF), it is demonstrated that these complexes can read out DNA sequence features to establish specific nucleosome-positioning patterns. For one of the remodelers, ACF, we identified a 40-bp DNA sequence element that directs nucleosome positioning. Furthermore, we show that nucleosome positioning by the remodelers ACF and Chd1 is determined by a reduced affinity to the end product of the translocation reaction. The results suggest that the linkage of differential remodeling activities with the intrinsic binding preferences of nucleosomes can result in establishing distinct chromatin structures that depend on the DNA sequence and define the DNA accessibility for other protein factors.