SPIO And Gd-DTPA Combining Enhanced MR Imaging Of Hepatocellular Carcinoma In Rat Model

SPIO And Gd-DTPA Combining Enhanced MR Imaging Of Hepatocellular Carcinoma In Rat ModelPostgraduate StudentLiii XianTutorial ProfessorsXu YikaiHuang QiliuABSTRACTObjectives:1. To assess the MR characteristics of rat liver carcinoma after superparamagnetic iron oxide combining with Gd-DTPA enhancement and compared with that of superparamagnetic iron oxide (SPIO), Gd-DTPA enhancement methods. 2. To evaluate the diagnostic efficacy of SPIO enhanced MRI in liver lesions by assessing the SPIQ-enhanced MR characteristics of hepatocellular carcinoma, regenerative nodule and focal nodular hyperplasia.3. To compare the different MR sequences by evaluating the SNR and CNR of hepatocellular carcinoma after SPIQ injection.Materials and Methods:1.In Vitro Experiment:SPIO were diluted to different concentration (2.5 i.?mol Fe/mi.. 5 i~ moi Fe/mI.. 10 i.i mol Fe/mL 15 vt mol Fe/mI.. 20 1.i mol Fe/mI.. 25 p mol Fe/mI.. 30 i.i mol Fe/mi.. 40 ~ moi Fe/mi), distilled water was selected as blank control. We also mixed 1M Gd-DTPA with each different concentration SPIO(5.. 10.. 20.. 30.. 40.. 50.. 60.. 80~moiFe/mi)equivalently, and selected distilled water as blank control. All the diluted series and distilled water were imaged in SE T1WI on a I .5-T MR scanner. And their signal intensities were analyzed.2.Animal ExperimentExperimental model of haptocellular carcinoma was induced in 30 rats by feeding DEA. MR imaging was performed before and after different enhancement protocols. MR sequences included SE T1WI (390ms/l4ms), TSE T2WI (4lOOms/99ms), SE Dual-echoes (l800ms/2Oms/7Oms), GRE FLASH T2*WI (600ms/lSms/150), GRE FLASH T1WI (lSOms/l4ms/700).The dual-contrast methods were achieved by the following two ways: firstly Gd-SPIO method was achieved by first administrating Gd-DTPA to the rat-5-mode1 (n=l0), SE, GRE Tl-weighted images were obtained, thenadministrated SPIO immediately, the same parameter am imaging wasperfOrmed, SPlO-Gd method was achieved by first administrating SPIO to therat model (n=l0), SE, GRE Tl-weighted images were obtained. l2 ndnuteslater after SPIO injection, Gd-DTPA was administrated, the same ffe imageswere performed.Gd-DTPA and SPIO were administrated intravenously to the rat modelrespectively as positive control groups (n=l0). We also used 20 normal rats asnegatiVe contro1 groups, adndnistrated Gd-DTPA. SPIO, Gd+SPIO and' ='SPIOedd respectively, MR images were pedermed in the same pulsesequences as t.lose used in unenhancemeflt. Aner am imaging study, all theanimals were killed, the specimens were prepared with standard hetatoxylin-eosin stain and Prussian blue iron stain fOr histologic examination of lesionsand iron deposition. The am findings were correlated with that ofhistologicalchanges.Results:l .ln Vitro Experiment f The signal intensity in Tl-weighted images increased atlower concentration of SPIO, contrarily, the signal intensity decreased whenthe concentration of SPIO increased. The same phenomenon was observed inGd-DTPA and SPIO ndXture.2.ANmal Experiment f(1). Aner SPIO enhancement, the signal intensity of normal liver andcirrhosis liver both decreased, especia1ly in GRE T,*-wieghted images. Therewas a significant difference between their PSIL in SE T2-weighted images, butthere was no significant difference in the other pulse sequences.(2). The SNR and CNR ofheptocellular carcinoma in both combining-contrast methods were improved considerably than those ofunenhanced, Gd-DTPA-enLhanced and SPIO-enhanced methods on Tl-weighted images. Butthere was no significant difference between combining-contrast methods andSPIO-enhanced method on T2 or T,*-weighted images.(3). After SPIO enhancement, the signal intensity of HCC, RN, and FN'H allincreased on Tl-weigted images. On T2 and T,*-weighted images, the signalintensity of HCC remained high, however, KN and FNH appeared significantlysignal losses. Aner SPIO adAnnistration, the CNR of HCC on GRE T,*--...