Ryuji Shirase

Age-Related Changes in Intramyocellular Lipid in Humans by in vivo 1H-MR Spectroscopy

Background: It is considered that the increasing intramyocellular lipid (IMCL) affects health risks and muscle attenuation. Though body fat increases significantly with age in lean humans, it is not known whether IMCL increases or not. In this study, we investigated the changes with age in IMCL concentrations in skeletal muscles using 1H-MR spectroscopy and studied them in relation to body fat percentage, waist-hip ratio, and blood components. Methods: Twenty-four lean young (age 21.2 ± 1.9, BMI 21.5 ± 1.8) and 23 lean old (age 70.9 ± 2.4, BMI 21.7 ± 1.3) subjects took part in the study. Subjects were grouped by gender into age- and BMI-matched young and old groups. The 1H-MRS was obtained from the tibialis anterior (TA), medial gastrocnemius (MG) and soleus (SOL) muscles. Results: The IMCL content in SOL and MG in the old was found to be higher (p < 0.01) than that in the young. No age difference in IMCL content in TA was found. IMCL concentrations in SOL were higher than those in MG and TA in the order of SOL > MG > TA (p < 0.01). IMCL content correlated significantly with waist-hip ratio in all skeletal muscles. A significant relationship was observed between percent body fat and IMCL in TA and MG (p < 0.05). However, no correlation was found between IMCL content in each muscle and BMI. The IMCL content in all skeletal muscles significantly correlated with HbA1c, triglyceride, total cholesterol and LDL cholesterol concentrations. Conclusion: These results suggest that increased IMCL in both lean older men and women might be related to body composition, blood lipids and lipoprotein profiles, and that this might affect muscle attenuation.

Double-subtraction maximum intensity projection MR angiography for detecting the artery of Adamkiewicz and differentiating it from the drainage vein

To evaluate the efficacy of double‐subtraction magnetic resonance angiography (MRA) (subtraction of the subtracted venous phase image from the subtracted arterial dominant phase image) for depicting the artery of Adamkiewicz and differentiating it from the drainage vein.

Gadolinium-enhanced dynamic magnetic resonance imaging with endorectal coil for local staging of rectal cancer.

PurposeThe aim of this study was to evaluate the accuracy of dynamic gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) with endorectal coil for assessing tumor invasion based on simple classification criteria.Materials and methodsA total of 58 patients with operable primary rectal cancer underwent preoperative MRI. An enhancement pattern in Gd-enhanced dynamic MRI with regard to tumor penetration was clarified. Retrospectively, two observers independently scored T2-weighted MRI and T2-weighted MRI combined with Gd-enhanced dynamic MRI for tumor penetration using the following criteria: With Gd-enhanced dynamic MRI, T1 tumors showed an early enhanced line around the tumor as rim enhancement; T2 tumors appeared as black lines or double layers, as the muscularis propria kept its integrity; T3 tumors showed partial discontinuity of the muscularis propria as a dotted line and a perforated area as an interrupted line. A confidence level scoring system was used, and receiver operating characteristic curves were generated.ResultsThere were no significant differences at the T1 stage. There were significant differences for observer 1 (P = 0.001 for observer 1) at the T2 stage. There were significant differences for both observers (P = 0.001 for observer 1 and P = 0.005 for observer 2) at the T3 stage.ConclusionOur criteria for Gd-enhanced dynamic MRI were effective for T3 stage tumors.

Investigation of Intervertebral Disc and Facet Joint in Lumbar Spondylolisthesis using T2 Mapping

PURPOSE We measured T2 relaxation time of the intervertebral discs (IVD) and facet joints (FJ) in patients with degenerative spondylolisthesis (DS) and no spondylolisthesis (NS) and investigated the characteristics of these parts in DS. METHODS In 40 patients with DS and 40 patients with NS, we measured T2 relaxation time of the IVD and FJ and compared them between groups. In the group with DS, we also examined the relationship between the degree of slippage using Meyerding grade and T2 relaxation of each part in the IVD and FJ. RESULTS T2 relaxation time of the IVD tended to be lower in the DS than NS group and differed significantly (P < 0.01) within the anterior annulus fibrosus. T2 relaxation time in the FJ was significantly higher in the DS than NS group. T2 relaxation time in the FJ was significantly higher for those assessed Meyerding Grade II than Grade I, although we observed no significant differences in T2 relaxation time in any area of the IVD. CONCLUSION T2 relaxation time decreased in the anterior annulus fibrosus of the IVD and increased in the FJ in patients with DS, suggesting an association of IVD and FJ degeneration with the development of lumbar DS.