The relationship between calcium (water) density and age distribution in adult women with spectral CT: initial result compared to bone mineral density by dual-energy X-ray absorptiometry.

BACKGROUND: Calcium (water) density (DCa(Wa)) of gemstone spectral imaging by spectral computed tomography (CT) is a new method of evaluating bone structures. PURPOSE: To investigate age-related change of DCa(Wa) of a chosen lumbar vertebra in adult women with spectral CT and the correlation between the DCa(Wa) and bone mineral density (BMD) of dual-energy X-ray absorptiometry (DXA). MATERIAL AND METHODS: A total of 305 adult women underwent spectral CT, 127 of whom simultaneously underwent DXA. All the patients were divided into 11 subgroups based on age. DCa(Wa) and BMD were measured at the second lumbar vertebra on the calcium (water)-based material decomposition images of spectral CT and DXA, respectively. A one-way analysis of variance (ANOVA) was performed for the difference of the measurements among adjacent age subgroups. Pearson correlation was used to assess the association between age and DCa(Wa), age and BMD, as well as DCa(Wa) and BMD. RESULTS: There was a significant negative correlation between DCa(Wa) and age (r = -0.719) as well as BMD and age(r = -0.851). The mean DCa(Wa) of L2 vertebral body was significantly different between the 40-44- and 45-49-, 45-49- and 50-54-, 55-59- and 60-64-, 65-69- and 70-74-year-old age subgroups. BMD was significantly different between the 35-39- and 40-44-, 45-49- and 50-54-, and 65-69- and 70-74-year-old age subgroups. There was a significant positive correlation between DCa(Wa) and BMD. CONCLUSIONS: The DCa(Wa) of lumbar vertebra by spectral CT demonstrated similar age distribution as BMD of DXA and could be used as a method of measuring the vertebral bone mineral density in adult women.

Reduction of metal artifacts from unilateral hip arthroplasty on dual-energy CT with metal artifact reduction software.

Background The evaluation of hip arthroplasty is a challenge in computed tomography (CT). The virtual monochromatic spectral (VMS) images with metal artifact reduction software (MARs) in spectral CT can reduce the artifacts and improve the image quality. Purpose To evaluate the effects of VMS images and MARs for metal artifact reduction in patients with unilateral hip arthroplasty. Material and Methods Thirty-five patients underwent dual-energy CT. Four sets of VMS images without MARs and four sets of VMS images with MARs were obtained. Artifact index (AI), CT number, and SD value were assessed at the periprosthetic region and the pelvic organs. The scores of two observers for different images and the inter-observer agreement were evaluated. Results The AIs in 120 and 140 keV images were significantly lower than those in 80 and 100 keV images. The AIs of the periprosthetic region in VMS images with MARs were significantly lower than those in VMS images without MARs, while the AIs of pelvic organs were not significantly different. VMS images with MARs improved the accuracy of CT numbers for the periprosthetic region. The inter-observer agreements were good for all the images. VMS images with MARs at 120 and 140 keV had higher subjective scores and could improve the image quality, leading to reliable diagnosis of prosthesis-related problems. Conclusion VMS images with MARs at 120 and 140 keV could significantly reduce the artifacts from hip arthroplasty and improve the image quality at the periprosthetic region but had no obvious advantage for pelvic organs.

Virtual monochromatic spectral imaging for the evaluation of vertebral inconspicuous osteoblastic metastases from lung.

Background The diagnosis of inconspicuous osteoblastic metastases (OBMs) is a challenge in computed tomography (CT) images. The virtual monochromatic spectral (VMS) image of spectral CT is useful for the detection of the low-contrast lesions. Purpose To select the optimal monochromatic level for VMS images of spectral CT for detecting and diagnosing inconspicuous OBMs of the vertebra from lung cancer. Material and Methods Thirty-five patients underwent spectral CT for chest or abdomen. The CT number and standard deviation (SD) of lesions and adjacent normal bone and the SD value of subcutaneous fat were measured on the conventional polychromatic image (140 kVp) and 40-140 keV VMS images. The contrast-to-noise ratio (CNR) was compared among the 11 VMS images and 140 kVp images. The scores of two observers for different images and the inter-observer agreement were evaluated. The diameter and CNR of the detected and missed lesions were assessed. Results The lowest image noise was distributed in 70 and 140 keV images and the highest CNR was noted in 70 keV images. Good and moderate inter-observer agreement were identified for the evaluation of diagnostic ability, and the subjective scores of two observers for 60 and 70 keV images were increased compared with 140 kVp images ( P < 0.05). The diameter had no significant difference between the detected and missed lesions. The CNR of the missed lesions was reduced compared with detected lesions. Conclusion VMS images at 70 keV may be optimal for detecting and diagnosing inconspicuous OBMs from lung cancer.

The changes of funny currents in the ventricular myocytes of neonatal rats and adult rats / 中国应用生理学杂志

<p><b>AIM</b>To record funny currents (If) of ventricular myocytes and to analysize hyperpolarization-activated cation channel(HCN) expression in the rats of different ages.</p><p><b>METHODS</b>Fresh ventricular myocytes were isolated from 3 days rats and adult rats.HCN expressions were measured by real-time quantitative polymerase chain reaction(real-time PCR). It was recorded through whole-cell patch clamp.</p><p><b>RESULTS</b>HCN1, HCN2, HCN3, HCN4 mRNA represented 0.23% +/- 0.01%, 83.58% +/- 0.04%, 0.79% +/- 0.01%, 15.44% +/- 0.01% of total HCN mRNA in the neonatal rats, respectively. If was recorded and the threshold for activation was -75 mV. In the adult rat, HCN1, HCN2, HCN3, HCN4 mRNA represented 0.72% +/- 0.02%, 91.58% +/- 0.08%, 0.27% +/- 0.02%, 7.12% +/- 0.02% of total HCN mRNA. The ratio of HCN2 to HCN4 was approximately (13.06 +/- 0.21):1. The threshold for activation of If was approximately -115 mV in the adult rats.</p><p><b>CONCLUSION</b>With the development of rats, the value of If is smaller. The threshold for activation of If is more negative. The ratio of HCN2 to HCN4 is bigger.</p>