Chemical shift magnetic resonance imaging for distinguishing minimal-fat renal angiomyolipoma from renal cell carcinoma: a meta-analysis.

OBJECTIVES: To determine the performance of chemical shift signal intensity index (CS-SII) values for distinguishing minimal-fat renal angiomyolipoma (mfAML) from renal cell carcinoma (RCC) and to assess RCC subtype characterisation. METHODS: We identified eligible studies on CS magnetic resonance imaging (CS-MRI) of focal renal lesions via PubMed, Embase, and the Cochrane Library. CS-SII values were extracted by lesion type and evaluated using linear mixed model-based meta-regression. RCC subtypes were analysed. Two-sided p value <0.05 indicated statistical significance. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RESULTS: Eleven articles involving 850 patients were included. Minimal-fat AML had significantly higher CS-SII value than RCC (p < 0.05); there were no significant differences between mfAML and clear cell RCC (cc-RCC) (p = 0.112). Clear cell RCC had a significantly higher CS-SII value than papillary RCC (p-RCC) (p < 0.001) and chromophobe RCC (ch-RCC) (p = 0.045). The methodological quality was relatively high, and Begg's test data points indicated no obvious publication bias. CONCLUSIONS: The CS-SII value for differentiating mfAML from cc-RCC remains unproven, but is a promising method for differentiating cc-RCC from p-RCC and ch-RCC. KEY POINTS: • RCC CS-SII values are significantly lower than those of mfAML overall. • CS-SII values cannot aid differentiation between mfAML and cc-RCC. • CS-SII values might help characterise RCC subtypes.

Myocardial Extracellular Volume Fraction Measured by Cardiac Magnetic Resonance Imaging Negatively Correlates With Cardiomyocyte Breadth in a Healthy Porcine Model.

Background: The extracellular volume fraction (ECV) derived from cardiac magnetic resonance imaging (MRI) is extensively used to evaluate myocardial fibrosis. However, due to the limited histological verification in healthy individuals, it remains unclear whether the size of cardiomyocytes may play a potential role in the physiological changes of ECV. The aim of this study was to examine the association between cardiomyocyte size and myocardial ECV by using a healthy porcine model. Methods: Sixteen domestic healthy pigs were anesthetized and underwent cardiac MRI with mechanical controlled breathing. Intravenous contrast medium was introduced at a dose of 0.2-0.25 mmol/kg. The interventricular septum ECV was calculated using an established MRI procedure, which was based on the pre- and post-contrast T1 values of the heart and individual blood hematocrit. The cardiomyocyte breadth (CmyB) in cross section was measured by hematoxylin and eosin staining to reflect the cardiomyocyte size. Results: Data were successfully acquired from 14 pigs. The CmyB was obtained from the myocardial tissues corresponding to the region of interest on cardiac MRI. The mean ± SD of the ECV was 0.253 ± 0.043, and the mean ± SD of the CmyB was 10.02 ± 0.84 µm. The ECV exhibited a negative correlation with the CmyB (r = -0.729, p = 0.003). Conclusion: The myocardial ECV detected by cardiac MRI is negatively correlated with the CmyB in healthy pigs, demonstrating that the size of cardiomyocytes is potentially associated with the ECV under physiological conditions.

Image quality and radiation exposure in pediatric cardiovascular CT angiography from different injection sites.

OBJECTIVE: The purpose of this article is to evaluate the effect of different injection sites (i.e., head, arm, or leg vein) on image quality and radiation exposure in pediatric cardiovascular CT angiography (CTA) with 64-MDCT. MATERIALS AND METHODS: CTA was performed in 61 children with suspected extracardiac abnormalities. Patients were assigned to three groups according to the different injection sites: head, arm, or leg vein. Enhancement of heart chamber and great vessels and background noise were quantified. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), dose-length product (DLP), and effective dose (ED) were calculated. Subjective image quality was assessed by two radiologists in consensus. RESULTS: There was no significant difference among all groups in the mean attenuation of the heart chamber, pulmonary artery (PA), and aorta. There was also no significant difference in their mean attenuation, background noise, SNR, and CNR. However, there were significant differences among the three groups for aorta image quality (p = 0.006), despite the nonsignificant differences in heart chamber and PA image quality. There also were significant differences among the three groups for total DLP and ED (p = 0.01 for both), with prescanning DLPs of 17.6%, 20.2%, and 24.5%, respectively, of the total DLP for each group. CONCLUSION: Although all injection sites can yield diagnostic-quality images with a low radiation dose in pediatric cardiovascular CTA, the injection site has a slight impact on the image quality of different targeted areas with a significantly different radiation dose. The optimization of a prescanning protocol may open an avenue to reduce the radiation dose associated with cardiovascular CTA.

Expression and ultrastructural localization of Mint2 in the spinal cord of rats.

Mint protein family, as adaptor molecules, contains three members, Mint1, Mint2 and Mint3. Although Mint3 is ubiquitously expressed, Mint1 and Mint2 have been reported to express specifically in neuron. Here we demonstrated Mint1 and Mint2 expression pattern in rat spinal cord. The protein level of Mint2 was found to be higher than that of Mint1 in rat spinal by western blot. In an attempt to know Mint2 distribution in the spinal cord of rat, in situ hybridization was carried out, Mint2 mRNA was showed to be ubiquitously distributed in cervical, thoracic and lumbar sections of rat spinal cord, and high intensive signal was detected in motor neurons. These were further confirmed by fluorescent immunohistochemistry, Mint2 was also found to exist throughout gray matter especially motor neurons where Mint2 was mainly located in perikaryon, however, Mint1 was showed to be relatively lower. By electron microscope, Mint2 was found to be mainly located in vesicles in perikaryon in motor neuron of lumbar section, and at the same time Mint2 was located in axons in myelin and presynaptic terminals. These data suggest that Mint2 may play more important role in spinal cord than the other two family members.

[Diagnostic value of 64 multislice CT in typing of congenital aortic anomaly in neonates and infants].

OBJECTIVE: To study diagnostic value of 64 multislice CT in typing of congenital aortic anomaly in neonates and infants. METHODS: 120 pediatric patients (under one year of age) with congenital heart disease (CHD) underwent 64 contrast-enhanced MSCT before a corrective operations. The diagnostic sensitivity, specificity and accuracy of 64 MSCT were evaluated and also compared with those of echocardiography with Doppler. The patients were randomly assigned to two groups (72 and 48 persons) respectively according to tube tension of 80 and 100 kV. The differences of the image qualities were compared between them. RESULTS: 36 congenital aortic anomalies were found (36/120, 30%) by 64 MSCT, which were furtherly distinguished into 2 cases in double aortic arch, 2 cases in left-sided aortic arch with aberrant right subclavian artery, 22 cases in right aortic arch (6 cases in right-sided aortic arch with aberrant left subclavian artery, 12 cases in right aortic arch with mirror image branching), 10 cases in coarctation of aorta. Diagnostic sensitivity, specificity and accuracy of 64 MSCT were all 100%. By contrast, those of echocardiography with Doppler were 27.8%, 97.6%, 76.7%, respectively. The quality scores were 4.69 ± 0.52, 4.58 ± 0.58 at 80 kV and 100 kV, respectively. No significant statistical difference was found between them (t = 1.08, P = 0.28). CONCLUSION: MSCT allows a detailed assessment of the anatomy of congenital aortic anomaly, which can be used as an important supplementary method in diagnosing CHD and offer important information for operation. 80 kV should be selected in CHD patients less than one year old for CT examination to reduce radiation exposure.

Intervertebral disc regeneration using platelet­rich plasma­containing bone marrow­derived mesenchymal stem cells: A preliminary investigation.

Platelet­rich plasma (PRP) is a promising strategy for intervertebral disc degeneration (IDD). However, the short half­life of growth factors released from PRP cannot continuously stimulate the degenerated discs. Thus, the present study hypothesized that the combined use of PRP and bone marrow­derived mesenchymal stem cells (BMSCs) may repair the early degenerated discs in the long term for their synergistic reparative effect. In the present study, following the induction of early IDD by annular puncture in rabbits, PRP was prepared and mixed with BMSCs (PRP­BMSC group) for injection into the early degenerated discs. As controls, phosphate­buffered saline (PBS; PBS group) and PRP (PRP group) were similarly injected. Rabbits without any intervention served as a control group. At 8 weeks following treatment, histological changes of the injected discs were assessed. Magnetic resonance imaging (MRI) was used to detect the T2­weighted signal intensity of the targeted discs at weeks 1, 2 and 8 following treatment. Annular puncture resulted in disc narrowing and decreased T2­weighted signal intensity. At weeks 1 and 3, MRI examinations showed regenerative changes in the PRP­BMSC group and PRP group, whereas the PBS group exhibited a continuous degenerative process of the discs. At 8 weeks post­injection, the PRP­BMSCs induced a statistically significant restoration of discs, as shown by MRI (PRP­BMSCs, vs.PRP and PBS; P<0.05), which was also confirmed by histological evaluations. Thus, compared with PRP, the administration of PRP­containing BMSCs resulted in a superior regenerative effect on the early degenerated discs, which may be a promising therapeutic strategy for the restoration of early degenerated discs.