Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: We investigated whether the preoperative flexion tear gap (FTG) observed in open magnetic resonance imaging (MRI) affects meniscus stability after medial meniscus (MM) posterior root (MMPR) repairs. Furthermore, time-correlated MRI findings from MMPR tear occurrence were evaluated. METHODS: This retrospective observational study included 54 patients (mean age, 64.6 years; 13 males and 41 females) who underwent pullout repair for radial degenerative MMPR tear. Meniscus stability (scored 0-4 points) was assessed using a semi-quantitative arthroscopic scoring system during second-look arthroscopy 1 year postoperatively. The FTG was evaluated on preoperative axial MRI at 90° knee flexion. Other MRI measurements included MM extrusion (MME) at 10° knee flexion, MM posterior extrusion (MMPE) at 90° knee flexion, and MM posteromedial extrusion (MMpmE) at 90° knee flexion preoperatively and 1 year postoperatively. The correlation between the arthroscopic stability score and MRI findings was investigated. A receiver-operating characteristic curve was calculated to predict a good meniscus healing score (3-4 points). The correlation between the FTG and patient demographics, including time from injury to MRI, was analyzed. RESULTS: At 1 year postoperatively, MME increased by 1.1 mm, while MMpmE and MMPE decreased by 0.4 mm and 1.0 mm, respectively. The meniscus stability score was negatively correlated with the preoperative FTG (r = -0.61, p < 0.01). The time from injury to MRI was significantly correlated with the preoperative FTG. The receiver-operating characteristic curve identified an FTG cut-off value of 8.7 mm for predicting good postoperative stability, with sensitivity and specificity of 67% and 85%, respectively. CONCLUSIONS: FTG evaluated with open MRI at 90° knee flexion was associated with time from injury and affected meniscus stability following pullout repair. MMPR tears should be treated in the early phase to increase meniscus healing stability.

DOI： 10.1186/s43019-025-00264-7

PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

Temporal bone computed tomography (CT) is frequently performed for pediatric patients with ear diseases. Advances in CT technology have improved diagnostic imaging quality, but reduction of radiation exposure remains a goal. We evaluated the potential for radiation dose reduction in temporal bone CT examinations using porcine ear ossicles and a photon-counting detector CT system. Three scans of the bilateral temporal bone were performed on each of three pig cadaver heads. In each of seven successive imaging sessions, the radiation dose was reduced by an additional one-seventh of the recommended dose (RD). Two board-certified radiologists independently scored the resulting images on a scale of 1 to 5 points, where 5 represented the image quality at the RD. Images scoring ≥4.5 points were considered acceptable. Noise was assessed in a 2-cm-diameter region near the ear ossicles, and standard deviation was measured for each of the seven decrements from the RD. As the radiation dose decreased, the noise progressively increased, and visual assessment scores progressively decreased. Acceptable image scores were obtained at six-sevenths (4.9), five-sevenths (4.8), four-sevenths (4.7), and three-sevenths (4.6) of the RD. Thus, acceptable porcine temporal bone CT images were obtained with a radiation dose reduction of approximately 50%.

DOI： 10.18926/AMO/68645

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Language：English   Publishing type：Research paper (scientific journal)  

This retrospective study investigated whether necrotic lesions detected on a computed tomography (CT) scan are more regressive than non-necrotic lesions after methotrexate withdrawal in patients pathologically diagnosed with methotrexate-associated lymphoproliferative disorders (MTX-LPD). In total, 89 lesions extracted from 24 patients on CT scans were included in the analysis. All patients had been evaluated for the presence of necrosis within lesions via CT scan upon first suspicion of MTX-LPD (baseline CT scan). The percentage lesion size reduction between the baseline and initial follow-up CT scan was calculated. The association between necrosis within lesions and size changes was estimated via linear regression analyses using both crude and adjusted models. Necrosis was significantly more common in extranodal lesions (27 out of 30 lesions, 90%) than in nodal lesions (9 out of 59 lesions, 15%, p<0.001). In the crude model, the regression of necrotic lesions was 58.5% greater than that of non-necrotic lesions; the difference was statistically significant (p<0.001). Additionally, the longest diameter of necrotic lesions at the baseline CT scan was significantly greater than that of non-necrotic lesions (p<0.001). Based on the adjusted model, necrotic lesions showed 49.3% greater regression than non-necrotic lesions (p=0.017). Necrosis detected on a CT scan was found to be an independent predictor of regression after MTX withdrawal in patients with MTX-LPD.

DOI： 10.18926/AMO/66668

PubMed

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.meddos.2019.07.006

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.meddos.2017.11.007

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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