[The Iron Content of Hepatocellular Carcinoma Associated Nodules: Study of Histopathology and MR Imaging].

OBJECTIVE: To explore the clinical value of MRI imaging of measuring the iron content for hepatocellular carcinoma (HCC) associated nodules. METHODS: 55 male Wistar rats were randomly allocated into a treatment and a control group, which were administered with diethyl nitrosamine (DEN) and the sterilized tap water. According to the macro pathology differences, the treatment groups were divided into three groups: cirrhotic nodules group, cirrhotic nodules with HCC group, and HCC group; According to the micro pathology differences, the treatment groups were divided into four groups: regenerative nodules (RN) group, low grade dysplastic nodules (LGDN) group, high grade dysplastic nodules (HGDN) group, and HCC group. After 13 weeks, the rats were scanned by MRI T2WI and T2 * WI. The next day all rats were sacrificed for histological tests and tissue iron level determination. The correlations were statically analyzed between the values of T2, T2 * and the grades of iron stain, the quantification of tissue iron. RESULTS: With macro pathology observation, the values of T2, T2 * among control group (normal rats) , cirrhotic nodules group, cirrhotic nodules with HCC group, HCC group were increased, while the quantification of tissue iron were decreased. Significant differences were found for T2, T2 * and quantification of tissue iron in three groups (P < 0.05). Low-grade negative correlations could be found between T2, T2 * and quantification of tissue iron in whole samples (r1 = -0.364, P1 = 0.000; r2 = -0.245, P2 = 0.018). With micro pathology observation, there were significant differences among the control (normal rats), RN, LGDN, HGDN, and HCC groups for the grades of iron stain both in the essence and the interstitial (P < 0.05). After comparison each two groups, significant differences were found among some groups for the grades of iron stain both in the essence and the interstitial (P < 0.05). Generally the grades of iron stain for HCCs were lower than non-HCC both in the essence and the interstitial. CONCLUSION: Negative correlation between T2, T2 * and iron content demonstrats that T2 and T2 * could roughly estimate the iron content in the cirrhotic nodules. T2 and T2 * measurements could contribute to differential diagnosis of HCC nodules.

[Application of black tea as a negative oral contrast in magnetic resonance cholangiopancreatography (MRCP)].

OBJECTIVE: To investigate the feasibility of using black tea as a gastrointestinal oral negative contrast agent to null the signal from fluid in bowel during MR cholangiopancreatography (MRCP). METHODS: (1) 15 different drinks were scanned with MRCP, T2-map and T1-map in vitro to identify the most suitable drink for MRCP. (2) 10 volunteers were scanned by MRCP prior to and 5, 10, 15 min after tea consumptions to identify the optimal delay time. (3) 20 patients were scanned with MRCP prior to and 5 min after tea consumptions. The signal intensity (SI) and signal-to-noise ratio (SNR) of stomach, duodenum, liver-parenchyma, common bile duct (CBD), pancreatic duct (PD) and gall bladder (GB); the singal loss of stomach and duodenum; and the image quality of ampulla of vater (AV), intrahepatic ducts (IHD), hepatic duct, CBD, PD and GB were analyzed with Siemens Workstation. RESULTS: (1) Lipton black-tea was identified as the optimal drink in vitro. (2) There were no significant differences in MRCP among the 3 delay times in volunteer tests. (3) The SI, SNR and SI loss of stomach and duodenum, and the image quality of CBD, PD, GB and AV showed a significant improvement of MRCP after tea consumptions (P < 0.05). But tea consumptions made no significant differences in the image quality of IHD and hepatic duct, and the SI and SNR of liver, CBD, GB and PD (P > 0.05). CONCLUSION: As a simple, cheap and safe drink, black tea can be widely used to reduce signal intensity of gastrointestinal tract and provide improved image of MRCP.

[Optimal protocol of MR contrast imaging in diabetic foot].

OBJECTIVE: To identify the optimal protocol of MR contrast imaging in diabetic foot. METHODS: 20 patients with diabetic feet were enrolled and examined with 3D FLASH-MRA, 3D VIBE-WE, 2D SE-FS, 2D TSE-FS and 2D FLASH-FS at a 1.5T MR scanner for vascular changes in feet. Their effectiveness in displaying blood vessels, venous aliasing and articular cartilage, as well as the signal-to-noise ratio (SNR) and contrast ratio (CR) of plantar skins calcaneus, flexor digitorum brevis, dorsal artery, and talocalcaneal joint cartilage in diabetic feet were compared. RESULTS: (1) 3D FLASH-MRA was better in displaying blood vessels and venous aliasing than the others (P < 0.05); (2) 3D VIBE-WE was better in displaying articular cartilage than 2D SE-FS, 2D TSE-FS and 2D FLASH-FS (P < 0.05); (3) 3D VIBE-WE had higher SNR and CR of plantar skins, dorsal artery, talocalcaneal joint cartilage, calcaneus, and flexor digitorum brevis than the others (P < 0.05). CONCLUSION: 3D VIBE-WE is the preferred sequence for T1 weighted imaging with contrast in diabetic feet. It can also serve as the supplemental sequence of 3D FLASH-MRA in MR angiography.

[Comparison of the efficacy of gadobutrol and multihance in contrast-enhanced MRI for diagnosis of brain metastasis in lung cancer].

OBJECTIVE: To investigate the diagnostic efficacy of gadobutrol for assessing brain metastases in lung cancer patients in comparison with multihance. METHODS: 21 patients with lung cancer suspected of brain metastasis were enrolled in this study. All patients underwent twice MRI scans on a 3.0T MRI scanner (Siemens MAGENETOM Trio) with 8-channel head coil, first with 0.5 mol/L multihance and then with 1.0 mol/L gadobutrol as contrast agent. The dosage of contrast agent was set at 0.1 mmol/kg body mass. The interval between the two scans was 24-72 hours. The detection and delineation of lesions were evaluated visually. The signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR) of lesion to normal brain white matter and the percentage of lesion enhancement were calculated and compared between the two scans by 2 experienced neuroradiologists. RESULTS: One patient was excluded because he received radiation therapy between the two scans. 15 patients were found to have brain metastases with a total of 35 lesions. There were no statistical differences between the two scans in SNR, CNR and percentage enhancement for both normal brain and lesions (t = 0.545, P = 0.592; t = 1.143, P = 2.267; t = 0.592, P = 0.557; t = 0.473, P = 0.639). CONCLUSION: Half-dose gadobutrol (1.0 mol/L) can achieve the same enhancement effects compared with full-dose multihance (0.5 mol/L).

[Peripheral MR angiography without contrast agent using fresh blood imaging (FBI) with ECG-trigger: initial experience].

OBJECTIVE: To examine the efficacy of fresh blood imaging (FBI) in detecting vascular diseases in lower extremity. METHODS: Thirty-six patients suspected of having lower extremity vascular diseases were imaged with a 1.5-T MRI system (Toshiba Excelart Vantage). Contrast-enhanced MRA (CEMRA) and FBI technology, with maximum intensity projection (MIP) reconstruction were adopted to visualize lower extremity vascular. Signal to noise ratios (SNR) were measured on the FBI and CEMRA images. Two experienced radiologists assessed the imaging quality of peripheral artery MRA on MIP reconstructed images. RESULTS: All patients successfully underwent both FBI and CEMRA. All arterial segments were obtained in the 36 patients. The SNR values on FBI and CEMRA were 108.39 +/- 9.76 and 87.46 +/- 14.77 (t = - 6.782, P = 0.001), respectively. There were no significant differences in the overall image quality, arterial anatomy and venous overlap (chi2 = 0.004, P = 0.947; chi2 = 0.000, P = 1; chi2 = 0.681, P = 0.409). The CEMRA motion artifacts were less than FBI (chi2 = 8.744, P = 0.03). CONCLUSION: The FBI technique, which shows the vascular disease in lower extremity without contrast medium with ECG gating, is considered clinically useful.

[MR spectroscopy of amygdala: space saturation technique improves spectral quality].

OBJECTIVE: To investigate the effect of space saturation technique on the quality of proton magnetic resonance spectroscopy (1 H-MRS) for amygdala. METHODS: 22 healthy volunteers were enrolled and scanned at a 3.0T MR scanner. Single voxel H-MRS of amygdala with and without space saturation bands around the region of interest was performed using point-resolved spectroscopy series (PRESS, TR/TE = 1500/30 ms). Raw spectral data were processed and signal-to-noise ratio of creatine (Cr-SNR), water-suppression level, full width at half maximum (FWHM) and root mean square (RMS) noise were obtained and compared between groups with and without saturation bands. RESULTS: The Cr-SNR of spectra without and with saturation bands was 15.506 +/- 6.623 and 22.935 +/- 7.270, respectively [increased by (47.9% +/- 24.94%), P < 0.001]. The water-suppression level of spectra without and with saturation bands was (93.888% +/- 1.079%) and (95.722% +/- 0.461%), respectively [increased by (1.95% +/- 0.68%), P < 0.001]. The FWHM of spectra without and with saturation bands was 7.00 +/- 1.113 and 6.82 +/- 1.181, respectively [decreased by (2.57% +/- 1.12%), P > 0.053. The RMS noise of spectra without and with saturation bands was 0.606 +/- 0.0615 and 0.589 +/- 0.0470, respectively [reduced by (2.81% +/- 1.68%), P > 0.053. CONCLUSION: Application of space saturation technique significantly elevates the Cr-SNR and the water-suppression level, and thus improves the spectral quality of amygdala without additional scanning time.

Diffuse lupus encephalopathy in a case of rhupus syndrome.

"Rhupus syndrome" is a rare clinical condition, which is related to anti-CCP antibody, characterized by overlapping clinical and immunologic features of rheumatoid arthritis and systemic lupus erythematosus. Previous reports mentioned that patients have more RA-associated damage, and little organic damage associated with SLE. The severe organ damage, especially central nervous system involvement has been reported to be rare in patients with rhupus syndrome. Here, we report a very rare concurrence of RA, SLE and diffuse lupus encephalopathy in a Chinese woman.

[Quantification of pancreas fat by MRS and FATSAT with 3.0T MRI].

OBJECTIVE: To test the values of MR spectroscopy (MRS) and fat saturation (FATSAT) in quantifying fat content in pancreas with 3.0T MR. METHODS: Thirty-five healthy volunteers were examined with 3 different MR techniques IP/OP, MRS, and FATSAT, to quantify pancreas fat content (FC). The IP/OP result served as a reference standard. RESULTS: The IP/OP, FATSAT and MRS detected (8.2 +/- 2.0)%, (11.8 +/- 4.7)% and (8.8 +/- 4.6)% of pancreas fat content, respectively. The IP/OP result correlated with the MRS result (r = 0.809, P < 0.001), but not with the FATSAT result (r = 0.311, P = 0.069). CONCLUSION: For 3.0T MRI, MRS technique can quantify pancreas fat content, but FATSAT can not.

[MR DTI and DTT study on the development of optic radiation in patients with anisometropia amblyopia].

OBJECTIVE: To evaluate the development of optic radiations (ORs) in patients with anisometropia amblyopia using magnetic resonance diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT), and to explore possible mechanism of pathogenesis of amblyopia. METHODS: Brain scan was performed with 3.0 Tesla scanner on 8 patients with anisometropia amblyopia and 15 control subjects with normal sights. The fractional anisotropy (FA) values, the apparent diffusion coefficient (ADC) values, the numbers of neural fiber bundle of ORs, and the voxel numbers of ORs were compared between the patients with anisometropia amblyopia and those with normal sights and between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia. RESULTS: No differences in the FA values, the ADC values, the numbers of neural fiber bundle of ORs and the voxel numbers of ORs were found between the ipsilateral ORs and the contralateral ORs in the patients with amblyopia (P > 0.05). Significant decreases in the FA values and the voxel numbers of ORs were found in the patients with amblyopia compared with the controls (P < 0.05). No differences in the voxel numbers of both ORs in the anterior parts were found between the patients with amblyopia and the controls (P > 0.05). However, the patients with amblyopia had more voxel numbers of ORs in the posterior parts than the controls (P < 0.05). The differences in the ADC values and the numbers of neural fiber bundle of ORs between the patients with amblyopia and the controls were not significant (P > 0.05). CONCLUSION: The compactability, integrity and directivity of ORs decrease in patients with anisometropia amblyopia. The projection of OR fibers is abnormal. The ORs are underdeveloped, especially in the posterior parts, although no abnormal morphologic changes occur. The DTI and DTT can detect the underdevelopment of optic radiations in patients with anisometropia amblyopia indirectly.

[Nonenhanced renal artery MR angiography with time spatial labeling inversion pulse technology and its clinical values].

OBJECTIVE: To evaluate the feasibility of nonenhanced renal artery MR angiography (MRA) with respiratory-gated time spatial labeling inversion pulse (time-slip) and its clinical application. METHODS: Thirty-two consecutive patients underwent the 1.5 T MRI (TOSHIBA EXCELART Vantage) examination to visualize renal artery with contrast-enhanced MRA (CEMRA) and the examination with time-slip technology. Signal to noise ratio (SNR) and contrast to noise ratio (CNR) were measured on CEMRA and Time-slip images, respectively. Two experienced radiologists assessed the imaging quality of renal artery MRA on 3D-MIPs reconstructed images. RESULTS: Sixty-four renal arteries and 3 accessory renal arteries in 32 patients were visualized on both time-slip and CEMRA. SNR values on Time-slip and CEMRA were 102.7 +/- 16.2 and 83.9 +/- 17.7 (t = -4.625, P < 0.001); CNR were 97.8 +/- 16.1 and 78.8 +/- 18.3 (t = -4.554, P < 0.001), respectively. Time-slip MIP images obtained higher quality than CEMRA did (Z = -2.318, P = 0.02), and venous contamination was sharply reduced on Time-slip technology when compared with CEMRA (Z = -4.895, P = 0.001). CONCLUSION: Non-enhanced renal artery MRA with respiratory-gated time-slip technology can provide higher SNR images of renal artery than conventional CEMRA, which can provide more information for clinical decision-making.

Correlations in spontaneous activity and gray matter density between left and right sensoritmotor areas of pianists.

Resting-state functional MRI and structural MRI were used to study correlations of spontaneous activity and gray matter density between the left and right primary sensorimotor areas in pianists and nonmusicians. Functional MRI analysis showed significant correlation of spontaneous activity between the left and right primary sensorimotor area in both groups; however, there was no between-group difference. Structural MRI analysis showed significant correlation in gray matter density between the left and right sensorimotor areas in nonmusicians (r=0.65, P=0.001), but not in pianists (r=0.07, P=0.78), with a significant between-group difference (P=0.035). The lack of correlation of gray matter density between the left and right sensorimotor areas might be the basis of bimanual coordination of the pianists.

MRI-negative refractory partial epilepsy: role for diffusion tensor imaging in high field MRI.

OBJECTIVE: Our aim is to use the high field MR scanner (3T) to verify whether diffusion tensor imaging (DTI) could help in locating the epileptogenic zone in patients with MRI-negative refractory partial epilepsy. METHOD: Fifteen patients with refractory partial epilepsy who had normal conventional MRI, and 40 healthy volunteers were recruited for the study. DTI was performed on a 3T MR scanner, individual maps of mean diffusivity (MD) and fractional anisotropy (FA) were calculated, and Voxel-Based Analysis (VBA) was performed for individual comparison between patients and controls. RESULT: Voxel-based analysis revealed significant MD increase in variant regions in 13 patients. The electroclinical seizure localization was concurred to seven patients. No patient exhibited regions of significant decreased MD. Regions of significant reduced FA were observed in five patients, with two of these concurring with electroclinical seizure localization. Two patients had regions of significant increase in FA, which were distinct from electroclinical seizure localization. CONCLUSION: Our study's results revealed that DTI is a responsive neuroradiologic technique that provides information about the epileptogenic areas in patients with MRI-negative refractory partial epilepsy. This technique may also helpful in pre-surgical evaluation.

[Brain structural differences of schizophrenia patients with and without family histories].

OBJECTIVE: To identify the brain structural differences of schizophrenia patients and their parents between those with family history and those sporadic cases. METHODS: High resolution T1 weighted images were obtained using 3T MR from 10 familial patients and 10 sporadic patients matched with age, sex, years of education and duration of disease. All patients were in their first episode of care. Twenty unaffected parents of the patients (8 for familial cases, 12 for sporadic cases) and 20 normal controls were also examined. The images were preprocessed according to the optimized VBM protocol. Student t test was performed to test the differences of the gray matter density (GMD) of the patients and their parents between the groups with and without family histories, and between the patient groups and the normal controls. RESULTS: Compared with the sporadic group, significant reduce of GMD was observed in bilateral thalamus in both familial schizophrenia patients and their parents. Compared with normal controls, both familial and sporadic schizophrenia patients showed lower GMD in many areas including bilateral insula, right temporal lobe, right occipital lobe, left lenticula, right cerebellum and left rectal gyrus extending to anterior cingulated gyrus. Only familial patients showed lower GMD in the right thalamus. Familial parents also showed lower GMD in several areas including right insula extending to right temporal lobe and right parietal lobule. CONCLUSION: Familial schizophrenia is associated with genetically related structural abnormalities, especially in the bilateral thalamus. The brain structural differences can explain, at least in part, the symptom differences between familial and sporadic schizophrenia.

Diffusion tensor MRI for the assessment of cerebral ischemia/reperfusion injury in the penumbra of non-human primate stroke model.

OBJECTIVES: The purpose of this study is to use diffusion tensor imaging (DTI) parameters to evaluate cerebral ischemia/reperfusion injury in the infarct core (IC) and ischemic penumbra (IP) in a rhesus transient middle cerebral artery occlusion (MCAO) model. METHODS: Seven rhesus monkeys were used to construct the MCAO model. The temporal evolution of the relative apparent diffusion coefficient (rADC) and the relative fractional anisotropy (rFA) in the IC area, infarct growth area (IG), and reversible penumbra area (RP) were investigated. RESULTS: The rADC increased in the three areas in the early stage of reperfusion (1 hour after the reperfusion). However, the rate of rADC improvement was significantly slower in IG than in IC and RP. Different temporal evolutions of rFA were observed in the three areas in the following stage of reperfusion (3-24 hours after the reperfusion), which continued to decline in IG but slightly elevated in IC and RP. DISCUSSION: These findings suggest that the evolution of DTI parameters can help in the assessment of cerebral ischemia/reperfusion injury in the penumbra and predict the growth of the infarction area after stroke.

Gray matter density and white matter integrity in pianists' brain: a combined structural and diffusion tensor MRI study.

The current study combined structural magnetic resonance imaging (sMRI) and diffusion tensor MRI (DT-MRI) to investigate both gray matter density (GMD) and white matter integrity (WMI) in 18 pianists and 21 age-matched non-musicians. The pianists began their piano training at a mean age of 12. Voxel-based morphometry of the sMRI data showed that the pianists had higher GMD in the left primary sensorimotor cortex and right cerebellum. Voxel-based analysis of the DT-MRI data showed that pianists had higher fractional anisotropy (FA) (indicating higher WMI) in the right posterior limb of the internal capsule. The sMRI and DT-MRI results indicate that both the GMD and WMI of pianists may exhibit movement-related increases during adolescence or even early adulthood compared with non-musicians.