Hong Zhang MD, Presenter: Nothing to Disclose

Na Xu Zhao PhD, Abstract Co-Author: Nothing to Disclose

Jinyuan Zhou PhD, Abstract Co-Author: Nothing to Disclose

Yun Peng MD, Abstract Co-Author: Nothing to Disclose

The study was performed with the aim of characterizing infectious lesions of different aetiology using protein-based APT imaging.

Children with brain infection [one with tuberculous abscess (TA), one with pyogenic abscess (PA); and three with viral encephalitis (VA)] that were diagnosed on the basis of laboratory, clinical, and radiologic findings were recruited in this study. MRI data was acquired using a Philips 3T MRI scanner, including multiple MRI scans, T1-weighted, T2-weighted, isotropic apparent diffusion constant (ADC), Gd-T1w, and APT-weighted. APTw MR imaging was based on the single-slice, single-shot TSE (saturation time = 800 ms; saturation power = 2 μT). The APT effect was quantified using an MT-ratio asymmetry analysis at the offset of 3.5 ppm: MTRasym(3.5ppm), and displayed using a window of -4% to 4%. The Gd-T1w image was used as the reference of ROI analysis.

Both TA and PA demonstrated clear gadolinium enhancement. The APTw signal was high in the gadolinium-enhancing rim of the lesion (2.30±0.07% in TA and 2.27±0.17% in PA), compared to peripheral edema (0.58±0.07% in TA and 0.91±0.02% in PA) and contralateral normal-appearing brain tissue (0.37±0.03% in TA and 0.45±0.03% in PA). This hyperintense rim on APTw MRI may be due to the inflammatory cellular infiltrate and granulomas, leading increased content of cellular proteins and peptides. Most non-enhancing areas on T1w may be liquifactive necrosis of the lesion, showing APTw iso-intensity. The portion inside the center of the lesion showing an APTw hyperintensity may be due to a large amount of neutrophils and proteins, which are released in the necrotic cavity. For VE, T2w showed a symmetric hyperintense lesion in the basal ganglia. The lesion shows no enhancement on Gd-T1w and iso-intensity on APTw, which may mainly be associated with vasogenic/interstitial collection of fluid. Thus, APT-MR imaging may help better distinguish the heterogeneous portions of infectious lesions.

These initial data show that APT-MR imaging is an important technique for the detection and characterization of infectious lesions of different aetiology.

APT-MRI may be a more sensitive biomarker in pediatric brain infection.

Zhang, H, Zhao, N, Zhou, J, Peng, Y, Amide Proton Transfer (APT) Imaging of Brain Infection in Children.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018392.html