Retrospective study of TACE in the treatment of lobaplatin-induced thrombocytopenia in primary hepatocellular carcinoma.

PURPOSE: To discuss postoperative thrombocytopenia in the treatment of hepatocellular carcinoma (HCC) through transcatheter arterial chemoembolization (TACE) with single application of Lobaplatin as chemotherapy drug. METHODS: The study retrospectively analyzed 1,945 HCC patients treated with TACE in our hospital from May 2013 to May 2018. The number of first-time users of lobaplatin reached 128, the second-time users reached 417, the third-time and above users 239. The analysis examined various items of patients, including gender, age, multiple preoperative examination indicators (platelet level, liver function tests, AFP level), ascites, preoperative presence of peptic ulcer at the initial (3-7 days) and long-term (21-90 days) postoperative stages. Platelet levels were evaluated according to the WHO Grading System for Hematologic Toxicity for side effects of anticancer drugs. RESULTS: For HCC patients with normal pre-intervention platelet level, the incidences of mild decrease, moderate decrease and severe decrease after intervention were 16.50%, 10.47% and 4.88% respectively, the incidences of long-term platelet reduction after intervention were 13.25%, 4.73% and 1.65% respectively. The level of post-intervention thrombocytopenia was not correlated with the cycles of lobaplatin use. The initial thrombocytopenia was more obvious in female patients after intervention. The presence or absence of peptic ulcer and ascites before the intervention had an effect on the initial thrombocytopenia after the intervention. Platelet level before intervention was correlated with that after intervention. The liver function grading before intervention had no effect on the two levels of thrombocytopenia after intervention. There was a correlation between AFP level grouping before intervention and initial thrombocytopenia after intervention. CONCLUSIONS: The long-term incidence of thrombocytopenia after interventional therapy was not high in TACE patients with HCC treated with LPT alone, which was relatively safe. Besides, the occurrence of thrombocytopenia after intervention had certain characteristics, which can be used to guide clinical practice, so as to reduce the incidence of thrombocytopenia or provide targeted symptomatic support treatment.

Differentiation between malignant and benign thyroid nodules and stratification of papillary thyroid cancer with aggressive histological features: Whole-lesion diffusion-weighted imaging histogram analysis.

PURPOSE: To explore the usefulness of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) derived from reduced field-of-view (r-FOV) diffusion-weighted imaging (DWI) in differentiating malignant and benign thyroid nodules and stratifying papillary thyroid cancer (PTC) with aggressive histological features. MATERIALS AND METHODS: This Institutional Review Board-approved, retrospective study included 93 patients with 101 pathologically proven thyroid nodules. All patients underwent preoperative r-FOV DWI at 3T. The whole-lesion ADC assessments were performed for each patient. Histogram-derived ADC parameters between different subgroups (pathologic type, extrathyroidal extension, lymph node metastasis) were compared. Receiver operating characteristic curve analysis was used to determine optimal histogram parameters in differentiating benign and malignant nodules and predicting aggressiveness of PTC. RESULTS: Mean ADC, median ADC, 5th percentile ADC, 25th percentile ADC, 75th percentile ADC, 95th percentile ADC (all P < 0.001), and kurtosis (P = 0.001) were significantly lower in malignant thyroid nodules, and mean ADC achieved the highest AUC (0.919) with a cutoff value of 1842.78 × 10-6 mm2 /s in differentiating malignant and benign nodules. Compared to the PTCs without extrathyroidal extension, PTCs with extrathyroidal extension showed significantly lower median ADC, 5th percentile ADC, and 25th percentile ADC. The 5th percentile ADC achieved the highest AUC (0.757) with cutoff value of 911.5 × 10-6 mm2 /s for differentiating between PTCs with and without extrathyroidal extension. CONCLUSION: Whole-lesion ADC histogram analysis might help to differentiate malignant nodules from benign ones and show the PTCs with extrathyroidal extension. J. Magn. Reson. Imaging 2016;44:1546-1555.

Multicontrast single-slab 3D MRI to detect cerebral metastasis.

OBJECTIVE: The purpose of this study was to evaluate the sensitivities and specificities of four single-slab 3D MRI sequences in the detection of cranial metastases: double inversion recovery (IR), T2 FLAIR, contrast-enhanced T2 FLAIR, and contrast-enhanced IR-prepared fast spoiled gradient-echo (FSPGR) sequences. SUBJECTS AND METHODS: Eighty-four patients underwent double IR and T2 FLAIR imaging using 3-T MRI. Then, 49 of 84 patients were randomly selected to undergo contrast-enhanced IR-prepared FSPGR before contrast-enhanced T2 FLAIR, and the other 35 patients underwent contrast-enhanced T2 FLAIR before contrast-enhanced IR-prepared FSPGR. Two experienced neuroradiologists reviewed the images by consensus on a workstation. Metastases were scored a negative, equivocal, or positive. For each metastasis, we recorded the anatomic area and size, and checked whether edema was present. RESULTS: A total of 210 cranial metastases in 56 of 84 patients were revealed. The sensitivities of double IR, T2 FLAIR, contrast-enhanced IR-prepared FSPGR, and contrast-enhanced T2 FLAIR sequences were 66.2%, 56.7%, 80.5%, and 99%, respectively. The specificities were 68.3%, 73%, 75.7%, and 82.4%. The areas under the receiver operating characteristic curve were 0.763, 0.709, 0.865, and 0.993. Contrast-enhanced T2 FLAIR imaging was found to have the highest sensitivity especially for detecting lesions in meninges (98.2%; p<0.0001) and gray matter (GM) (100%; p<0.0001). The double IR sequence was superior to the T2 FLAIR sequence for imaging metastases located in ependyma (81.8% vs 36.4%) and GM (66.7% vs 48.1%). Delayed enhancement did not affect the sensitivities of the contrast-enhanced T2 FLAIR and contrast-enhanced IR-prepared FSPGR sequences. CONCLUSION: Contrast-enhanced T2 FLAIR is the most sensitive sequence of the four MR sequences evaluated for the detection of cranial metastases despite its delay time after contrast enhancement.

Grade classification of neuroepithelial tumors using high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy and pattern recognition.

Clinical data have shown that survival rates vary considerably among brain tumor patients, according to the type and grade of the tumor. Metabolite profiles of intact tumor tissues measured with high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS (1)H NMRS) can provide important information on tumor biology and metabolism. These metabolic fingerprints can then be used for tumor classification and grading, with great potential value for tumor diagnosis. We studied the metabolic characteristics of 30 neuroepithelial tumor biopsies, including two astrocytomas (grade I), 12 astrocytomas (grade II), eight anaplastic astrocytomas (grade III), three glioblastomas (grade IV) and five medulloblastomas (grade IV) from 30 patients using HRMAS (1)H NMRS. The results were correlated with pathological features using multivariate data analysis, including principal component analysis (PCA). There were significant differences in the levels of N-acetyl-aspartate (NAA), creatine, myo-inositol, glycine and lactate between tumors of different grades (P<0.05). There were also significant differences in the ratios of NAA/creatine, lactate/creatine, myo-inositol/creatine, glycine/creatine, scyllo-inositol/creatine and alanine/creatine (P<0.05). A soft independent modeling of class analogy model produced a predictive accuracy of 87% for high-grade (grade III-IV) brain tumors with a sensitivity of 87% and a specificity of 93%. HRMAS (1)H NMR spectroscopy in conjunction with pattern recognition thus provides a potentially useful tool for the rapid and accurate classification of human brain tumor grades.

Quantitative MR phase-corrected imaging to investigate increased brain iron deposition of patients with Alzheimer disease.

PURPOSE: Brain iron deposition has been proposed to play an important role in the pathophysiology of neurodegenerative diseases. The aim of this study was to investigate the correlation of brain iron accumulation with the severity of cognitive impairment in patients with Alzheimer disease (AD). MATERIALS AND METHODS: This study was approved by the institutional review board of Tongji Hospital (Wuhan, China) and written informed consent was obtained from all participants. Fifteen patients with AD, 15 age-and sex-matched healthy controls, and 30 healthy volunteers underwent high-resolution magnetic resonance (MR) phase-corrected imaging. The phase shift and iron concentrations of the bilateral hippocampus (HP), parietal cortex (PC), frontal white matter, putamen (PU), caudate nucleus (CN), thalamus, red nucleus, substantia nigra, and dentate nucleus (DN) of the cerebellum were examined for correlation with severity of dementia by using a two-tailed Student-Newman-Keuls t test (analysis of variance) and linear correlation test. RESULTS: Regional phase shifts on phase-corrected images were negatively correlated with regional brain iron concentration in healthy adults (r = -0.926, P = .003). Iron concentrations in the bilateral HP, PC, PU, CN, and DN subregions of patients with AD were significantly higher than the controls (P < .05), Moreover, these brain iron concentrations, especially those in the PC at the early stages of AD, were positively correlated with the severity of patients' cognitive impairment (P < .05). CONCLUSION: Iron concentration in the PC was positively correlated with the severity of AD patients' cognitive impairment, indicating that it may be used as a biomarker to evaluate the progression of AD.

Magnetic resonance susceptibility weighted imaging in detecting intracranial calcification and hemorrhage.

BACKGROUND: Computed tomography (CT) is better than routine magnetic resonance imaging (MRI) in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging (SWI) in the detection and differentiation of intracranial calcification and hemorrhage. METHODS: Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift (PS) of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically. RESULTS: The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT (P > 0.05). There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was +0.734 +/- 0.073 and -0.112 +/- 0.032 respectively (P < 0.05). The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal. CONCLUSIONS: SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.

Proton magnetic resonance spectroscopy in neonates with hypoxic-ischemic injury and its prognostic value.

It is difficult to predict the neurologic outcome of neonates with hypoxic-ischemic encephalopathy (HIE). Our goal was to investigate the prognostic values of magnetic resonance spectroscopy (MRS) in neonatal HIE. During this study, 46 neonates with HIE underwent magnetic resonance imaging (MRI) and proton MRS ((1)HMRS). The sample included 25 cases of mild HIE, 11 cases of moderate HIE, and 10 cases of severe HIE. Nine healthy neonates without asphyxia served as controls. (1)HMRS techniques included single-voxel MRS and 2-D-point-resolved spatially localized spectroscopy (PRESS) multivoxel chemical shift spectroscopy imaging. Then, 31 of 46 neonates with HIE were divided into 3 groups according to their prognosis: dead, abnormal, and normal outcome. Abnormal and normal outcome were defined by follow-up MRI. Metabolic changes were analyzed and compared with HIE grading and prognosis. As a result, the GLx-alpha peak was markedly increased in the moderate and severe HIE groups. The GLx-alpha/Cr ratio in the control, mild, moderate, and severe HIE groups was 0.18, 0.21, 0.64, 1.31, respectively. The Lac/Cr ratio was 0.12, 0.14, 0.19, and 0.26, respectively. A Spearman rank correlation test confirmed that the ratio of GLx-alpha/Cr and Lac/Cr had significant positive correlation with clinical grading of HIE (P < 0.01). The GLx-alpha/Cr ratio in the dead, abnormal, and normal outcome groups was 1.28, 0.82, and 0.25, respectively; the Lac/Cr ratio was 0.34, 0.19, and 0.14, respectively. An anaylsis of variance demonstrated that the differences were significant (both P < 0.01). A Spearman rank correlation test confirmed that the ratio of GLx-alpha/Cr and Lac/Cr had significant negative correlation with prognosis of HIE; GLx-alpha/Cr showed a much stronger correlation than the Lac/Cr ratio (P < 0.01). The formula of the relationship between the poor prognosis of HIE and the ratio of GLx-alpha/Cr in basal ganglia was established by the logistic regression model. In conclusion, (1)HMRS is a useful tool for evaluating the severity and prognosis of HIE. The higher ratio of GLx-alpha/Cr in the basal ganglia and thalamus may predict a poor outcome in neonates with HIE.

Diffusion MRI in ischemic epiphysis of the femoral head: an experimental study.

PURPOSE: To evaluate whether line-scan diffusion-weighted imaging (LSDWI) can provide temporal information of epiphyseal ischemia. MATERIALS AND METHODS: Ischemia was induced by ligation of arteries of the unilateral femoral head in piglets (N = 25). LSDWI was performed at several time points after ligation. A comparison of apparent diffusion coefficients (ADCs) was made between ischemic and control sides. The difference in percentage change of ADC in the ischemic hips between two neighboring time points was evaluated. A histological study was made after MR scanning. RESULTS: Three hours after ligation, ADCs were significantly lower in the ischemic hips than in the contralateral (control) hips. At 72 hours after surgery, ADCs in the ischemic hips were significantly higher than in the control hips and continued to rise up until the sixth week after operation. Histological study revealed necrosis of chondrocytes and osteocytes and abnormal thickening of the epiphyseal cartilage in the ischemic femoral head. CONCLUSION: The ADCs may be used as a marker of ischemia and necrosis in the femoral head; changes in the ADCs after the acute ischemia may reflect the evolution of ischemia and subsequent necrosis. LSDWI can be used for the evaluation of the duration and extent of ischemic injury in the epiphysis.

[The application of proton magnetic resonance spectroscopy and computerized tomography in evaluating nonalcoholic fatty liver disease].

OBJECTIVE: To investigate the application of proton magnetic resonance spectroscopy (1HMRS) and computerized tomography (CT) in evaluating nonalcoholic fatty liver disease (NAFLD). METHODS: Twenty-two NAFLD patients were selected, according to the Chinese Medical Association standard, and compared with 20 healthy persons (as the control group). Their body mass index (BMI), waist to hip ratio (WHR), and blood pressure (BP) were examined. The serum ALT, the concentration of fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), and uric acid (UA) were tested simultaneously. The severity of hepatosteatosis was evaluated by 1HMRS and CT scans of their livers. The intrahepatic content of lipid (IHCL) and CT liver and spleen ratios were measured. RESULTS: The BMI, WHR, serum ALT, FBG, TG, and UA were all elevated significantly in the NAFLD group and were (28.4+/-2.4) kg/m2, 0.91+/-0.04, (71.5+/-24.8) U/L, (5.67+/-0.61) mmol/L, (2.48+/-1.46) mmol/L, (420.7+/-57.5)micromol/L, respectively, P less than 0.01 or 0.05. Meanwhile, in the NAFLD group, the IHCL calculated by 1HMRS were increased and CT value ratios were decreased significantly compared with those of the control group (27.49%+/-12.27% vs 1.34%+/-0.79%, P less than 0.01). However, there was no correlation between the clinical features and the IHCL and between the clinical features and CT value ratios, but a negative correlation existed in the CT value ratio and IHCL. CONCLUSIONS: The intrahepatic content of lipids can be measured precisely by 1HMRS, and 1HMRS is better than CT in quantitative evaluations of NAFLD.

Experimental study of cell migration and functional differentiation of transplanted neural stem cells co-labeled with superparamagnetic iron oxide and BrdU in an ischemic rat model.

OBJECTIVE: To explore the migration of transplanted neural stem cells co-labeled with superparamagnetic iron oxide (SPIO) and bromodeoxyuridine (Brdu) using the 4.7T MR system and to study the cell differentiation with immuno-histochemical method in ischemic rats. METHODS: Rat neural stem cells (NSCs) co-labelled with SPIO mediated by poly-L-lysine and bromodeoxyuridine (BrdU) were transplanted into the unaffected side of rat brain with middle cerebral artery occlusion (MCAO). At weeks 1, 2, 3, 4, 5, and 6 after MCAO, migration of the labelled cells was monitored by MRI. At week 6, the rats were killed and their brain tissue was cut according to the migration site of transplanted cells indicated by MRI and subjected to Prussian blue staining and immunohistochemical staining to observe the migration and differentiation of the transplanted NSCs. RESULTS: Three weeks after transplantation, the linear hypointensity area derived from the migration of labelled NSCs was observed by MRI in the corpus callosum adjacent to the injection site. Six weeks after the transplantation, the linear hypointensity area was moved toward the midline along the corpus callosum. MRI findings were confirmed by Prussian blue staining and immunohistochemical staining of the specimen at week 6 after the transplantation. Flourescence co-labelled immunohistochemical methods demonstrated that the transplanted NSCs could differentiate into astrocytes and neurons. CONCLUSION: MRI can monitor the migration of SPIO-labelled NSCs after transplantation in a dynamical and non-invasive manner. NSCs transplanted into ischemic rats can differentiate into astrocytes and neurons during the process of migration.

Superparamagnetic iron oxide labeling of neural stem cells and 4.7T MRI tracking in vivo and in vitro.

Neural stem cells were labeled with superparamagnetic iron oxide (SPIO) and tracked by MRI in vitro and in vivo after implantation. Rat neural stem cells were labeled with SPIO combined with PLL by the means of receptor-mediated endocytosis. Prussian blue staining and electron microscopy were conducted to identify the iron particles in these neural stem cells. SPIO-labeled cells were tracked by 4.7T MRI in vivo and in vitro after implantation. The subjects were divided into 5 groups, including 5 x 10(5) labeled cells cultured for one day after labeling, 5 x 10(5) same phase unlabeled cells, cell culture medium with 25 mug Fe/mL SPIO, cell culture medium without SPIO and distilled water. MRI scanning sequences included T(1)WI, T(2)WI and T(2)*WI. R(2) and R(2)* of labeled cells were calculated. The results showed: (1) Neural stem cells could be labeled with SPIO and labeling efficiency was 100%. Prussian blue staining showed numerous blue-stained iron particles in the cytoplasm; (2) The average percentage change of signal intensity of labeled cells on T(1)WI in 4.7T MRI was 24.06%, T2WI 50.66% and T(2)*WI 53.70% respectively; (3) T2 of labeled cells and unlabeled cells in 4.7T MRI was 516 ms and 77 ms respectively, R(2) was 1.94 s(-1) and 12.98 s(-1) respectively, and T(2)* was 109 ms and 22.9 ms, R(2)* was 9.17 s(-1) and 43.67 s(-1) respectively; (4) Remarkable low signal area on T(2)WI and T(2)*WI could exist for nearly 7 weeks and then disappeared gradually in the left brain transplanted with labeled cells, however no signal change in the right brain implanted with unlabeled cells. It was concluded that neural stem cells could be labeled effectively with SPIO. R2 and R(2)* of labeled cells were increased obviously. MRI can be used to track labeled cells in vitro and in vivo.

Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets.

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

Evaluation of large intracranial aneurysms with cine MRA and 3D contrast-enhanced MRA.

The value of combined application of both ECG-gated cine MRA and 3D-CEMRA in the detection of large intracranial aneurysms was evaluated and the findings were compared with those of conventional MRA and DSA. Twenty-four patients with 26 large intracranial aneurysms underwent MRI and DSA. All these aneurysms, diameter from 15 to 39 mm, were located at internal cerebral artery (n=12), vertebral artery (n=3), basilar artery (n=4), anterior cerebral artery (n=2), middle cerebral artery (n=2), anterior communicate artery (n=2) and posterior communicate artery (n=1). Thirteen cases of hematoma or cavernoma were studied as control group. All patients were examined on GE 1.5T MR system. ECG-gated cine MRA was performed with 2D multi-phase fast gradient-recalled echo sequence in a single section. All the images were analyzed with signal intensity VS time curve for differentiating intraaneurysmal blood flow from static tissue. The results were analyzed by statistic "t" test. 3D-CEMRA was performed with spoiled gradient-recalled echo and one dose of Gd-DTPA. All data was processed with multi-plannar reformat (MPR) and tomography for the demonstration of aneurysms in detail. All 26 aneurysms were demonstrated successfully by combined application of both cine MRA and 3D-CEMRA. Compared to DSA and conventional 3D-MOTSA, its sensitivity and specificity figures were both 100%. Cine MRA could differentiate the blood flow from the static tissue. The intensity VS time curves of intraaneurysmal blood flow offered fluctuating form and average signal change between systole and diastole period was about 89.8 +/- 37.4; However, under the control group, intraaneurysmal thrombus or cerebral hemorrhage or cavernomas had no significant signal change and the curves offered steady form with the average signal change being about 8.2 +/- 6.3. There was statistically significant difference between the intraaneurysmal blood flow and static tissue (P=0.025, <0.05). 3D-CEMRA was very useful in demonstrating the aneurysmal size, intraaneurysmal thrombus formation, neck and the detailed relationship of the aneurysm to the surrounding structures. It was concluded that the combined application of both cine MRA and 3D-CEMRA might be a valuable clinical tool for the detection of large intracranial aneurysms.

Dynamic changes of the CT perfusion parameters in the embolic model of cerebral ischemia.

To study the dynamic changes of CT perfusion parameters during the first 12 h in the embolic cerebral ischemia models. Local cerebral ischemia model were established in 7 New Zealand white rabbits. All CT scans were performed with a GE Lightspeed 16 multislice CT. Following the baseline scan, further CT perfusion scans were performed at the same locations 20 min, 1-6 h and 8, 10 and 12 h after the embolus delivery. Maps of all parameters were obtained by CT perfusion software at each time point. The brains, taken 12 h after the scan, were sliced corresponding to the positions of the CT slices and stained by 2,3,5-triphenyltetrazolium chloride (TTC). On the basis of the TTC results, the ischemic sides were divided into 3 regions: core, penumbra and the relatively normal region. The changes of all parameters were then divided into 3 stages. In the first two hours (the first stage), the CBV dropped more remarkably in the core than in the penumbra but rose slightly in the relatively normal region while the CBF decreased and MTT, TTP extended in all regions to varying degrees. In the 2nd-5th h (the second stage), all the parameters fluctuated slightly around a certain level. In the 5th-12th h (the third stage), the CBV and CBF dropped, and MTT and TTP were prolonged or shortened slightly in the core and penumbra though much notably in the former while the CBV, CBF rose and MTT, TTP were shortened remarkably in the relatively normal region. We experimentally demonstrated that the location and extent of cerebral ischemia could be accurately assessed by CT perfusion imaging. The pathophysiology of the ischemia could be reflected by the CT perfusion to varying degrees.

Comparative study of 3D-SPGR vs 2D-SE T1WI after enhancement in the brain.

The utility of three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) imaging in the cerebral diseases was evaluated and 3D-SPGR after enhancement in depicting contrast enhancement of all lesions and 2D-SE T1WI comparatively analyzed. 117 patients were subjected to MRI by a GE 1.5T MR system. After performance of axial T1WI and T2WI in all patients, MRA (3D-MOTSA) images were acquired in 6 cases (8 lesions) of aneurysms. After enhancement, 3D-SPGR images were obtained in all the remaining patients. Quality parameters (SNR, C and CNR) were calculated on enhanced 2D-SE T1WI and 3D-SPGR images. And a four-point scale was used to measure the signal intensity of the main lesions on both sequences, then statistical analysis of the average score was performed with "t" test. Except for aneurysms, 2D-SE T1WI detected 134 lesions and 3D-SPGR disclosed 147 lesions. It was found that there was no statistically significant difference between the two average scores as determined by the "t" test (t = 1,894, P > 0.05). The enhancement degree of the main lesion was equivalent on 3D-SPGR and 2D-SE T1WI. Quality parameters (SNR, C and CNR) on 2D-SE T1WI were much larger than that of 3D-SPGR, increasing by an average of 57%, 20% and 97% respectively. 3D-SPGR imaging with MPR could clearly depict vascularity related to neoplasms in 20 cases and demonstrate shifted, deformed and blocked vessels involved by tumors. Six cases of large aneurysms (8 lesions) were visualized more clearly on 3D-SPGR than MRA (3D-MOTSA): 3D-SPGR could display aneurysm necks and differentiate thrombosed portion from the patent lumen, and disclose relationship of aneurysm to surrounding structures. It was concluded that enhanced 3D-SPGR played an important role in the depiction of the cerebral lesions and was superior to 2D-SE T1WI in many aspects.

MRI and magnetic resonance angiography in evaluating simultaneous pancreas-kidney transplantation.

OBJECTIVE: To evaluate the value of magnetic resonance imaging (MRI) and three dimensional (3D) contrast magnetic resonance angiography (MRA) in the diagnosis of complications of simultaneous pancreas-kidney transplantation (SPKT), as confirmed by biopsy and digital subtraction angiography (DSA). METHODS: Five MR examinations of five patients were performed within 28 days to 2 years after surgery on GE 1.5T MR system. Imaging techniques included axial and sagittal chemical fat-suppressed T1-weighted image (T1WI) and T2-weighted image (T2WI), additional contrast axial or saggital chemical fat-suppressed T1WI were obtained after 3D contrast MRA for calculating the mean percentage of the parenchymal enhancement (MPPE) of the pancreas and kidney. 3D contrast MRA was performed with Smartprep technique. MRA data were analyzed with maximum intensity projection (MIP) and multi-planner reformat (MPR). RESULTS: In five cases of transplant pancreases, MRI found two normal pancreas grafts, one case of acute rejection, one case of chronic rejection with 70% fibrosis and one case of late pancreatitis. In five transplant kidneys, MRI detected four normal kidney grafts and one case of acute rejection with infarction. MPPE could distinguish infarction from other complications. 3D contrast MRA could display vascular complications of SPKT, such as stenosis or occlusion, aneurysm formation of transplanted vessels and narrowing at the site of anastomosis, as confirmed by DSA. CONCLUSION: With combined application of MRI and 3D contrast MRA, complications of SPKT can be clearly identified.