Measurement of deoxyinosine adduct: Can it be a reliable tool to assess oxidative or nitrosative DNA damage?

Adenosine deaminases (ADA) are key enzymes that deaminate adenosine (A) or deoxyadenosine (dA) and produce inosine or deoxyinosine (dI), respectively. While ADA only deaminates free dA, reactive nitrogen species (RNS) or reactive oxygen species (ROS) deaminate adenine base on the DNA and leave dI, which is a pre-mutagenic lesion. Therefore, dI adduct in the genomic DNA has been considered a biomarker of DNA damage caused by RNS or by ROS.     

Diffuse Ependymal Dysembryoplastic Neuroepithelial Tumor Causing Spinal Drop Metastases: A Case Report

Dysembryoplastic neuroepithelial tumors (DNETs) arise mostly in the supratentorial cerebral cortex. A very rare case of intraventricular DNET with diffuse ependymal involvement, which causes spinal drop metastasis, is presented.     

MR Imaging in Patients with Suspected Liver Metastases: Value of Liver-Specific Contrast Agent Gadoxetic Acid

Objective

To compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance (MR) imaging with that of triple-phase multidetector-row computed tomography (MDCT) in the detection of liver metastasis.

Materials and Methods

Our institutional review board approved this retrospective study and waived informed consent. The study population consisted of 51 patients with hepatic metastases and 62 patients with benign hepatic lesions, who underwent triple-phase MDCT and gadoxetic acid-enhanced MRI within one month. Two radiologists independently and randomly reviewed MDCT and MRI images regarding the presence and probability of liver metastasis. In order to determine additional value of hepatobiliary-phase (HBP), the dynamic-MRI set alone and combined dynamic-and-HBP set were evaluated, respectively. The standard of reference was a combination of pathology diagnosis and follow-up imaging. For each reader, diagnostic accuracy was compared using the jackknife alternative free-response receiver-operating-characteristic (JAFROC).

Results

For both readers, average JAFROC figure-of-merit (FOM) was significantly higher on the MR image sets than on the MDCT images: average FOM was 0.582 on the MDCT, 0.788 on the dynamic-MRI set and 0.847 on the combined HBP set, respectively (p < 0.0001). The differences were more prominent for small (≤ 1 cm) lesions: average FOM values were 0.433 on MDCT, 0.711 on the dynamic-MRI set and 0.828 on the combined HBP set, respectively (p < 0.0001). Sensitivity increased significantly with the addition of HBP in gadoxetic acid-enhanced MR imaging (p < 0.0001).

Conclusion

Gadoxetic acid-enhanced MRI shows a better performance than triple-phase MDCT for the detection of hepatic metastasis, especially for small (≤ 1 cm) lesions.