Bone microarchitectural analysis using ultra-high-resolution CT in tiger vertebra and human tibia.

BACKGROUND: To reveal trends in bone microarchitectural parameters with increasing spatial resolution on ultra-high-resolution computed tomography (UHRCT) in vivo and to compare its performance with that of conventional-resolution CT (CRCT) and micro-CT ex vivo. METHODS: We retrospectively assessed 5 tiger vertebrae ex vivo and 16 human tibiae in vivo. Seven-pattern and four-pattern resolution imaging were performed on tiger vertebra using CRCT, UHRCT, and micro-CT, and on human tibiae using UHRCT. We measured six microarchitectural parameters: volumetric bone mineral density (vBMD), trabecular bone volume fraction (bone volume/total volume, BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and connectivity density (ConnD). Comparisons between different imaging resolutions were performed using Tukey or Dunnett T3 test. RESULTS: The vBMD, BV/TV, Tb.N, and ConnD parameters showed an increasing trend, while Tb.Sp showed a decreasing trend both ex vivo and in vivo. Ex vivo, UHRCT at the two highest resolutions (1024- and 2048-matrix imaging with 0.25-mm slice thickness) and CRCT showed significant differences (p ≤ 0.047) in vBMD (51.4 mg/cm3 and 63.5 mg/cm3 versus 20.8 mg/cm3), BV/TV (26.5% and 29.5% versus 13.8 %), Tb.N (1.3 l/mm and 1.48 l/mm versus 0.47 l/mm), and ConnD (0.52 l/mm3 and 0.74 l/mm3 versus 0.02 l/mm3, respectively). In vivo, the 512- and 1024-matrix imaging with 0.25-mm slice thickness showed significant differences in Tb.N (0.38 l/mm versus 0.67 l/mm, respectively) and ConnD (0.06 l/mm3 versus 0.22 l/mm3, respectively). CONCLUSIONS: We observed characteristic trends in microarchitectural parameters and demonstrated the potential utility of applying UHRCT for microarchitectural analysis.

Immunoglobulin G4-related periaortitis complicated by aortic rupture and aortoduodenal fistula after endovascular AAA repair.

PURPOSE: To report a rare and complicated case of immunoglobulin (Ig) G4-related periaortitis involving both the aortic wall and the retroperitoneum without aneurysmal formation. CASE REPORT: A 79-year-old man with IgG4-related periaortitis suffered aortic rupture despite a normal caliber aorta after 6 months of steroid therapy (20 mg/d). Endovascular repair with an aortic cuff sealed the rupture. Steroid therapy was halted 2 weeks later due to infection. Four months later, a biopsy during esophagogastroduodenoscopy to investigate gastrointestinal bleeding suggested a relapse of IgG4-RD in the duodenum. Subsequent aortoduodenal fistula formation proved fatal. Generally, IgG4-related periaortitis does not result in such complications due to the absence of aneurysm formation and a thick aortic wall. CONCLUSIONS: Our report highlights a rare case of IgG4-related periaortitis where complications resulted following steroid therapy and surgical intervention, emphasizing the difficulties in dealing with IgG4-related cardiovascular lesions.

Assessment of still and moving images in the diagnosis of gastric lesions using magnifying narrow-band imaging in a prospective multicenter trial.

OBJECTIVES: Magnifying narrow-band imaging (M-NBI) is more accurate than white-light imaging for diagnosing small gastric cancers. However, it is uncertain whether moving M-NBI images have additional effects in the diagnosis of gastric cancers compared with still images. DESIGN: A prospective multicenter cohort study. METHODS: To identify the additional benefits of moving M-NBI images by comparing the diagnostic accuracy of still images only with that of both still and moving images. Still and moving M-NBI images of 40 gastric lesions were obtained by an expert endoscopist prior to this prospective multicenter cohort study. Thirty-four endoscopists from ten different Japanese institutions participated in the prospective multicenter cohort study. Each study participant was first tested using only still M-NBI images (still image test), then tested 1 month later using both still and moving M-NBI images (moving image test). The main outcome was a difference in the diagnostic accuracy of cancerous versus noncancerous lesions between the still image test and the moving image test. RESULTS: Thirty-four endoscopists were analysed. There were no significant difference of cancerous versus noncancerous lesions between still and moving image tests in the diagnostic accuracy (59.9% versus 61.5%), sensitivity (53.4% versus 55.9%), and specificity (67.0% versus 67.6%). And there were no significant difference in the diagnostic accuracy between still and moving image tests of demarcation line (65.4% versus 65.5%), microvascular pattern (56.7% versus 56.9%), and microsurface pattern (48.1% versus 50.9%). Diagnostic accuracy showed no significant difference between the still and moving image tests in the subgroups of endoscopic findings of the lesions. CONCLUSIONS: The addition of moving M-NBI images to still M-NBI images does not improve the diagnostic accuracy for gastric lesions. It is reasonable to concentrate on taking sharp still M-NBI images during endoscopic observation and use them for diagnosis. TRIAL REGISTRATION: Umin.ac.jp UMIN-CTR000008048.