Objective To investigate the characteristics of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of association fiber tracts in patients with amnestic mild cognitive impairment (aMCI), and to assess the application value of diffusion tensor imaging (DTI) in differential diagnosis of aMCI and AD. Methods DTI were performed in 20 patients of aMCI (aMCI group), 20 patients of AD (AD group) and 20 normal control subjects (control group). FA and ADC values were calculated in the regions of interest (ROI) in inferior fronto-occipital fasciculus (IFOF), genu and splenium of corpus callosum, superior longitudinal fasciclesⅡ (SLFⅡ) and cingulated bundles. Results There was significant difference of FA values in inferior fronto-occipital fasciculus and cingulate bundles between aMCI group compared with control group (P<0.05), as well as of FA values in cingulate bundles between aMCI group and AD group (P<0.05). Conclusion Abnormal FA values in inferior fronto-occipital fasciculus and cingulate bundles suggest that DTI can be used as a diagnosis index of aMCI. Furthermore, it is helpful in the differential diagnosis of aMCI and AD.

Objective To investigate the factors affecting Fly-Thru (FT) and the best reconstruction conditions in a bile duct model.Methods The bile duct model was made with corn powder and rubber pipes.FT data of bile duct in vitro were acquired with a 3-dimensional probe of Toshiba Aplio 500,and the data were reconstructed offline in Fly-Thru workstation.Two US doctors assessed the FT images in three degrees.Results The images were divided into good,moderate and poor groups with corresponding score 3,2,1.Of 162 images,72 were rated as grade 1,57 as grade 2 and 33 as grade 3.According to x2 analysis,the diameter,scanning way,and Filter were brought into multinomial regression,then the scanning way was found to be correlated to FT images quality as well as filter (likelihood ratio =87.598,294.290,x2 =9.492,313.722,respectively,P ＜0.01).Best images of FT can be acquired by transverse scanning,reconstructing in Filter =3,gain =5(0,dynamic range (DR) =50 and threshold ranging 40-90.Conclusions Best FT images in the model could be achieved by scanning in short-axis,and reconstructing the data in Filter =3,gain =50,DR =5(0 and threshold ranging 40-90,which would be basic information for advanced clinic study.

Objective To investigate the utility of virtual endoscopy ultrasound Fly-Thru in the diagnosis of obstructive bile duct diseases.Methods One-hundred patients with obstructed bile duct diseases underwent Fly-Thru examination.All Fly-Thru images were reviewed by two radiologists with different experience.The capabilities of Fly-Thru for bile duct obstructive degree evaluation and distinguishing malignant lesion from benign one were assessed respectively.Results The accuracy and sensitivity of Fly-Thru image in obstruction degree evaluation were 70.59％ and 89.2％ (95％CI 74.6％-96.9％).The diagnosis accuracy of 2DUS for lesion characteristics increased from 80％ to 84％,accompany with Fly-Thru images,especially for lesions in common bile duct from 77.2％ to 86.0％ (x2 =14.399,P =0.001).Conclusions The virtual endoscopy ultrasound Fly-Thru is only partly capable to display the obstructed degree of some bile ducts,but it can improve the diagnostic accuracy of common bile duct diseases.

Objective To comparatively analyze CEUS features of hepatitis B virus (HBV)-related combined hepatocellular-cholangiocarcinoma (CHC) and hepatocellular carcinoma (HCC).Methods Thirty-one patients with HBV-related CHC and 31 patients with HBV-related HCC confirmed by pathology were enrolled and CEUS features were compared.Results On CEUS,HBV-related CHC and HBV-related HCC mainly manifested as hyper-enhanced in arterial phase and hypo-enhanced in portal phase and delayed phase.No significant differences of enhancement level on CEUS were found between HBV-related CHC and HBV-related HCC.When the maximum diameter of tumor ≤3.0 cm,both HBV-related CHC and HBV-related HCC were mainly homogeneous enhancement (P=1.000).When the maximum diameter of tumor more than 3.0 cm,diffuse heterogeneous enhancement and peripheral irregular rim-like enhancement were more commonly observed in HBV-related CHC,while diffuse heterogeneous enhancement was more commonly noted in HBV-related HCC (P=0.001).Conclusion The enhancement pattern of HBV-related CHC ＞3.0 cm has relative specific performance.

OBJECTIVETo compare the performance of three different types of RF coil in 3.0T MRI, the signal-to-noise ratio (SNR) and image uniformity in 3.0 Tesla magnetic resonance imaging system have been studied.

MATERIALS AND METHODSIn addition to the measurement of SNR and Uniformity based on the protocol recommend by AAPM, the images had also been analyzed using SPSS and MATLAB to get the SNR distribution along two vertical direction and the whole imaging plane.

RESULTSThe SNR with T/R birdcage coil and 8-ch surface coil is seven and twelve times higher than surface coil in the region of interest (ROI), which was set in the center of the phantom images. With regard to the spatial variation of sensitivity, the uniformity of T/R birdcage coil and 8-ch surface coil are also much higher than that of surface coil.

CONCLUSIONThe images from T/R birdcage and phased array coils are all better than those of surface coil. The SNR of the images from phased array coil is highest while the uniformity of the images from T/R birdcage coil is highest.

Magnetic Resonance Imaging ; instrumentation ; Materials Testing ; methods ; Phantoms, Imaging ; Radio Waves ; Signal-To-Noise Ratio