Abdominal MRI at 3.0 T: LAVA-Flex compared with conventional fat suppression T1-weighted images.

PURPOSE: To study liver imaging with volume acceleration-flexible (LAVA-Flex) for abdominal magnetic resonance imaging (MRI) at 3.0 T and compare the image quality of abdominal organs between LAVA-Flex and fast spoiled gradient-recalled (FSPGR) T1-weighted imaging. MATERIALS AND METHODS: Our Institutional Review Board approval was obtained in this retrospective study. Sixty-nine subjects had both FSPGR and LAVA-Flex sequences. Two radiologists independently scored the acquisitions for image quality, fat suppression quality, and artifacts and the values obtained were compared with the Wilcoxon signed rank test. According to the signal intensity (SI) measurements, the uniformity of fat suppression, the contrast between muscle and fat and normal liver and liver lesions were compared by the paired t-test. The liver and spleen SI on the fat-only phase were analyzed in the fatty liver patients. RESULTS: Compared with FSPGR imaging, LAVA-Flex images had better and more homogenous fat suppression and lower susceptibility artifact (qualitative scores: 4.70 vs. 4.00, 4.86% vs. 7.14%, 4.60 and 4.10, respectively). The contrast between muscle and fat and between the liver and pathologic lesions was significantly improved on the LAVA-Flex sequence. The contrast value of the fatty liver and spleen was higher than that of the liver and spleen. CONCLUSION: The LAVA-Flex sequence offers superior and more homogenous fat suppression of the abdomen than does the FSPGR sequence. The fat-only phase can be a simple and effective method of assessing fatty liver.

Liver dynamic contrast-enhanced MRI for staging liver fibrosis in a piglet model.

PURPOSE: To determine whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could monitor progression of liver fibrosis in a piglet model, and which DCE-MRI parameter is most accurate for staging this disease. MATERIALS AND METHODS: Sixteen piglets were prospectively used to model liver fibrosis and underwent liver DCE-MRI followed by biopsy on the 0, 5th, 9th, 16th, and 21st weekends after modeling of fibrosis. Time of peak (TOP), time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI), and maximum slope of decrease (MSD) were measured and statistically analyzed for the monitoring and staging. RESULTS: As fibrosis progresses, TOP and TTP tended to increase, whereas MSI, MSD, and PEI tended to decrease (all P < 0.05). TOP, TTP, and MSI could discriminate fibrosis stage 0 from 1-4, 0-1 from 2-4, 0-2 from 3-4, and 0-3 from 4; PEI could distinguish the above-mentioned stages except 0-3 from 4; and MSD could distinguish stage 0-3 from 4, and 0 from 1-4 (all P < 0.05). For predicting stage ≥1, ≥2, and ≥3, the area under receiver operating characteristic curve (AUC) of MSI was largest among all parameters; for stage 4 AUC of TTP was largest. CONCLUSION: DCE-MRI has the potential to dynamically stage progression of liver fibrosis.

Diameters of left gastric vein and its originating vein on magnetic resonance imaging in liver cirrhosis patients with hepatitis B: Association with endoscopic grades of esophageal varices.

AIM: To determine whether diameters of the left gastric vein (LGV) and its originating vein are associated with endoscopic grades of esophageal varices. METHODS: Ninety-eight liver cirrhotic patients with hepatitis B undergoing magnetic resonance (MR) portography, and upper gastrointestinal endoscopy for grading esophageal varices were enrolled. Diameters of the LGV and its originating vein - the splenic vein (SV) or portal vein (PV) - were measured on MR imaging. Statistical analyses were performed to identify the association of the diameters with the endoscopic grades. RESULTS: Univariate analysis showed that the SV was predominantly the originating vein of the LGV, and diameters of the LGV and SV were associated with grades of esophageal varices. Diameters of the LGV (P = 0.023, odds ratio [OR] = 1.583) and SV (P = 0.012, OR = 2.126) were independent risk factors of presence of the varices. Cut-off LGV diameters of 5.1 mm, 5.9 mm, 6.6 mm, 7.1 mm, 7.8 mm and 5.8 mm; or cut-off SV diameters of 7.3 mm, 7.9 mm, 8.4 mm, 9.5 mm, 10.7 mm and 8.3 mm, could discriminate grades 0 from 1, 0 from 2, 0 from 3, 1 from 3, 2 from 3, and 0-1 from 2-3, respectively. CONCLUSION: Diameters of the LGV and SV are associated with endoscopic grades of esophageal varices.

Spleen size measured on enhanced MRI for quantitatively staging liver fibrosis in minipigs.

PURPOSE: To investigate whether and how spleen size measured on magnetic resonance imaging (MRI) could be used to stage liver fibrosis. MATERIALS AND METHODS: Sixteen minipigs were used to prospectively model liver fibrosis staged by biopsy. Abdominal gadolinium-enhanced MRI was performed on the 0, 5th, 9th, 16th, and 21st weekend after beginning of the modeling. Splenic maximal width (W), thickness (T), length (L), and area (S) together with spleen volume (SV) and liver volume (LV) were measured on enhanced MRI and the ratio of SV to LV (SV/LV) was calculated. Spleen multidimensional indexes 1 and 2 were obtained by W × T × L and S × L, respectively. Statistical analyses were performed to determine which parameter could best stage the fibrosis. RESULTS: W, T, L, S, SV, index 1 and 2, and SV/LV tended to increase with increasing stages of fibrosis (r = 0.46-0.796, all P < 0.001), and might predict liver fibrosis stage ≥1, ≥2, ≥3, and 4 (area under receiver operating characteristic curve [AUC] = 0.697-1.0, all P < 0.05). Among the parameters, splenic index 1, SV, and SV/LV might be best for predicting stage ≥1 (AUC = 0.941), ≥2 or ≥3 (AUC = 0.875 or 0.978, respectively), and 4 (AUC = 1.0), respectively. CONCLUSION: Spleen size measured on MRI could be used for staging liver fibrosis.

Spleen magnetic resonance diffusion-weighted imaging for quantitative staging hepatic fibrosis in miniature pigs: An initial study.

AIM: To determine whether spleen diffusion-weighted imaging (DWI) parameters might classify liver fibrosis stage. METHODS: Sixteen miniature pigs were prospectively used to model liver fibrosis, and underwent spleen DWI by using b = 300, 500 and 800 s/mm(2) on 0, 5th, 9th, 16th and 21st weekend after the beginning of modeling. Signal intensity ratio of spleen to paraspinous muscles (S/M), spleen exponential apparent diffusion coefficient (eADC) and apparent diffusion coefficient (ADC) for each b-value were statistically analyzed. RESULTS: With increasing stages of fibrosis, S/M for all b-values showed a downward trend; and spleen eADC and ADC for b = 300 s/mm(2) showed downward and upward trends, respectively (all P < 0.05). The area under the receiver-operator curve (AUC) of spleen DWI parameters was 0.777 or more by S/M for classifying each fibrosis stage, and 0.65 or more by eADC and 0.648 or more by ADC for classifying stage ≥3 or cirrhosis. Among the spleen DWI parameters, S/M for b = 300 s/mm(2) was the best parameter in classifying stage 1 or more, 2 or more and 3 or more with AUC of 0.875, 0.851 and 0.843, respectively; and spleen eADC for b = 300 s/mm(2) was best in classifying stage 4 with an AUC of 0.988. CONCLUSION: Spleen DWI may be used to stage liver fibrosis.

Use of conventional MR imaging and diffusion-weighted imaging for evaluating the risk grade of gastrointestinal stromal tumors.

PURPOSE: To study the risk grade of gastrointestinal stromal tumors (GISTs) with conventional MR imaging and diffusion-weighted imaging (DWI). MATERIALS AND METHODS: The abdominal MR images with DWI of 23 patients with pathologically proven GISTs during January 2010 to May 2011 were retrospectively reviewed. The conventional MR imaging findings and apparent diffusion coefficient (ADC) values of the tumors related to the risk grade were analyzed. RESULTS: In the 23 patients, there were 13 patients with high-risk, 5 with medium-risk, 5 with low-risk, and 0 with very low-risk GISTs. Most of the conventional MR findings of the tumors did not correlate with the risk grade. The only exception to this was the correlation between risk grade and the enhancement degree of the tumor after Gd-DTPA. The ADC values were, respectively, (1.04 ± 0.13) × 10(-3) mm(2) ·s(-1) , (1.59 ± 0.06) × 10(-3) mm(2) ·s(-1) and (1.94 ± 0.08) × 10(-3) mm(2) ·s(-1) (P < 0.05) in the high-, medium-, and low-risk grade groups. The ADC values of GISTs decreased with the increase of the risk grade of the tumors (r = -0.957; P < 0.05). CONCLUSION: DWI can be used to assess the risk grade of GISTs, but conventional MR imaging is of limited use.

Gadobenate dimeglumine-enhanced liver magnetic resonance imaging: value of hepatobiliary phase for the detection of focal liver lesions.

OBJECTIVE: The objective of the study was to determine the value of addition of hepatobiliary phase to dynamic gadobenate dimeglumine (Gd-BOPTA)-enhanced imaging for the detection of focal liver lesions (nodules with diameter ≤3.0 cm). METHODS: Routine nonenhanced magnetic resonance images were obtained in 25 patients with focal liver lesions suggested by ultrasonography and/or computed tomography.T1-weighted dynamic gradient-echo images were acquired immediately and 100 minutes after bolus injection of Gd-BOPTA. The number of the lesions detected by T1-weighted imaging, T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhanced, and delayed hepatobiliary-phase imaging was counted, respectively. Contrast-to-noise ratios were measured for all the sequences including delayed hepatobiliary-phase imaging. The signal intensity and morphologic features of liver parenchyma and lesions were recorded and analyzed. RESULTS: There were 7 patients with hepatocellular carcinomas, 6 with hemangiomas, 7 with metastases, and 5 with cholangiocarcinomas. The delayed hepatobiliary-phase imaging showed a homogeneous enhancement of liver parenchyma and distinctive enhancement features of focal liver lesions. The delayed hepatobiliary-phase imaging was better than diffusion-weighted imaging for the detection of focal liver lesions (P < 0.05). CONCLUSION: The addition of hepatobiliary-phase imaging to Gd-BOPTA-enhanced dynamic imaging increased the sensitivity and accuracy for the detection of focal hepatic lesions.

Intravoxel incoherent motion diffusion-weighted imaging of resectable oesophageal squamous cell carcinoma: association with tumour stage.

OBJECTIVE: To determine whether intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) derived parameters can be associated with tumour stage of oesophageal squamous cell carcinoma (SCC). METHODS: 60 patients with resectable oesophageal SCC and 20 healthy individuals underwent oesophageal DWI-using multi b-values with a 3.0 T MR system. Pure diffusion coefficient (D), perfusion-related incoherent microcirculation (D*), microvascular volume fraction (f) and apparent diffusion coefficient (ADC) were measured on DWI. Statistical analyses were performed to determine associations of DWI-derived parameters with T-stage. RESULTS: ADC (r = -0.842), D (r = -0.729), D* (r = -0.301) and f (r = -0.817) were negatively correlated with T-stage of oesophageal SCC (all p < 0.01), and the multinominal regression analyses revealed that IVIM-derived parameters including D (p = 0.038; odds ratio <1) and f (p < 0.001; odds ratio <1) were associated with T-stage. The Mann-Whitney U tests with Bonferroni correction showed that D, f and ADC could discriminate oesophageal SCC, especially T1-staged tumour, from normal oesophagus (all p < 0.05) while D* could not (p > 0.05). By receiver operating characteristic analyses, f could be the best indicator for detecting oesophageal SCC with an area under receiver operating characteristic (AUC) of 0.964, especially T1-staged cancer with an AUC of 0.984, and for discriminating T1-stages between T0-1 and T2-3 with an AUC of 0.957, and between T0-2 and T3 with an AUC of 0.945 in comparison with any other DWI-derived parameter. CONCLUSIONS: IVIM derived parameters can be associated with T-stage of oesophageal SCC. Advances in knowledge (1) IVIM-derived parameters are negatively correlated with stage of oesophageal SCC. (2) Among IVIM-derived parameters, microvascular volume fraction helps detect and stage oesophageal SCC.

MR venography of the inferior mesentery vein.

OBJECTIVE: To evaluate on three-dimensional (3D) dynamic contrast-enhanced (DCE) MR venography (MRV), the visibility of the inferior mesenteric vein (IMV), its insertion pattern into the portal system, and the difference of IMV diameters between healthy subjects and patients with cirrhosis. MATERIALS AND METHODS: Two hundred and seventeen consecutive patients who had abdominal 3D DCE MRI was included in this study. The original image data of 3D DCE MRI was used to generate multiple planar volume reconstruction (MPVR) images, which were evaluated for visualization of the IMV and its pattern of insertion into the portal system. The diameter of IMV was measured and compared in 24 patients with cirrhosis (Cirrhosis Group) and in 30 patients without hepatic lesions or liver disease (Healthy Group). RESULTS: In the 217 patients, the frequencies of visualization of IMV, grade 1 order branches and grade 2 order branches were, respectively, 88%, 24% and 9%. The IMV inserted into the splenic vein (SV), the portal confluence and the superior mesenteric vein (SMV) in 45%, 18% and 37%, respectively. Among patients with cirrhosis, 12.5% had IMV diameter larger than 5.1mm, although there was no significant difference between cirrhosis and healthy groups (P>0.05). However, the diameters of the main portal vein (MPV), SV and SMV were significantly larger in the Cirrhosis Group (P<0.05). CONCLUSION: The IMV and its branches can be depicted well by 3D DCE MRV. The most common insertion of the IMV is into the splenic vein. A minority of patients with cirrhosis had dilatation of the IMV.

The Blood Oxygenation T2* Values of Resectable Esophageal Squamous Cell Carcinomas as Measured by 3T Magnetic Resonance Imaging: Association with Tumor Stage.

OBJECTIVE: To explore the association between the blood oxygenation T2* values of resectable esophageal squamous cell carcinomas (ESCCs) and tumor stages. MATERIALS AND METHODS: This study included 48 ESCC patients and 20 healthy participants who had undergone esophageal T2*-weighted imaging to obtain T2* values of the tumors and normal esophagi. ESCC patients underwent surgical resections less than one week after imaging. Statistical analyses were performed to identify the association between T2* values of ESCCs and tumor stages. RESULTS: One-way ANOVA and Student-Newman-Keuls tests revealed that the T2* value could differentiate stage T1 ESCCs (17.7 ± 3.3 ms) from stage T2 and T3 tumors (24.6 ± 2.7 ms and 27.8 ± 5.6 ms, respectively; all ps < 0.001). Receiver operating curve (ROC) analysis showed the suitable cutoff T2* value of 21.3 ms for either differentiation. The former statistical tests demonstrated that the T2* value could not differentiate between stages T2 and T3 (24.6 ± 2.7 ms vs. 27.8 ± 5.6 ms, respectively, p > 0.05) or between N stages (N1 vs. N2 vs. N3: 24.7 ± 6.9 ms vs. 25.4 ± 4.5 ms vs. 26.8 ± 3.9 ms, respectively; all ps > 0.05). The former tests illustrated that the T2* value could differentiate anatomic stages I and II (18.8 ± 4.8 ms and 26.9 ± 5.9 ms, respectively) or stages I and III (27.3 ± 3.6 ms). ROC analysis depicted the same cutoff T2* value of 21.3 ms for either differentiation. In addition, the Student's t test revealed that the T2* value could determine grouped T stages (T0 vs. T1-3: 17.0 ± 2.9 ms vs. 25.2 ± 6.2 ms; T0-1 vs. T2-3: 17.3 ± 3.0 ms vs. 27.1 ± 5.3 ms; and T0-2 vs. T3: 18.8 ± 4.2 ms vs. 27.8 ± 5.6 ms, all ps < 0.001). ROC analysis indicated that the T2* value could detect ESCCs (cutoff, 20 ms), and discriminate between stages T0-1 and T2-3 (cutoff, 21.3 ms) and between T0-2 and T3 (cutoff, 20.4 ms). CONCLUSION: The T2* value can be an additional quantitative indicator for detecting ESCC except for stage T1 cancer, and can preoperatively discriminate between some T stages and between anatomic stages of this tumor.

The celiac ganglia: anatomic study using MRI in cadavers.

OBJECTIVE: Our objective was to facilitate the in vivo identification of the celiac ganglia on MRI by using MRI to identify the celiac ganglia in cadavers. CONCLUSION: MRI can show the celiac ganglia accurately in cadavers when the ganglia are large and labeled with gadolinium. The findings in cadavers can be a reference for identifying the celiac ganglia in vivo.

Acute interstitial edematous pancreatitis: Findings on non-enhanced MR imaging.

AIM: To study the appearances of acute interstitial edematous pancreatitis (IEP) on non-enhanced MR imaging. METHODS: A total of 53 patients with IEP diagnosed by clinical features and laboratory findings were underwent MR imaging. MR imaging sequences included fast spoiled gradient echo (FSPGR) fat saturation axial T1-weighted imaging, gradient echo T1-weighted (in phase), single shot fast spin echo (SSFSE) T2-weighted, respiratory triggered (R-T) T2-weighted with fat saturation, and MR cholangiopancreatography. Using the MR severity score index, pancreatitis was graded as mild (0-2 points), moderate (3-6 points) and severe (7-10 points). RESULTS: Among the 53 patients, IEP was graded as mild in 37 patients and as moderate in 16 patients. Forty-seven of 53 (89%) patients had at least one abnormality on MR images. Pancreas was hypointense relative to liver on FSPGR T1-weighted images in 18.9% of patients, and hyperintense in 25% and 30% on SSFSE T2-weighted and R-T T2-weighted images, respectively. The prevalences of the findings of IEP on R-T T2-weighted images were, respectively, 85% for pancreatic fascial plane, 77% for left renal fascial plane, 55% for peripancreatic fat stranding, 42% for right renal fascial plane, 45% for perivascular fluid, 40% for thickened pancreatic lobular septum and 25% for peripancreatic fluid, which were markedly higher than those on in-phase or SSFSE T2-weighted images (P<0.001). CONCLUSION: IEP primarily manifests on non-enhanced MR images as thickened pancreatic fascial plane, left renal fascial plane, peripancreatic fat stranding, and peripancreatic fluid. R-T T2-weighted imaging is more sensitive than in-phase and SSFSE T2-weighted imaging for depicting IEP.

Liver Lobe Based Multi-Echo Gradient Recalled Echo T2*-Weighted Imaging in Chronic Hepatitis B-Related Cirrhosis: Association with the Presence and Child-Pugh Class of Cirrhosis.

PURPOSE: To investigate whether liver lobe based T2* values measured on gradient recalled echo T2*-weighted imaging are associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis. METHODS: Fifty-six patients with hepatitis B-related cirrhosis and 23 healthy control individuals were enrolled in this study and underwent upper abdominal T2*-weighted magnetic resonance imaging. T2* values of the left lateral lobe (LLL), left medial lobe (LML), right lobe (RL) and caudate lobe (CL) were measured on T2*-weighted imaging. Statistical analyses were performed to determine the association between liver lobe based T2* values and the presence and Child-Pugh class of cirrhosis. RESULTS: The T2* values of the LLL, LML and RL decreased with the progression of cirrhosis from Child-Pugh class A to C (r = -0.231, -0.223, and -0.395, respectively; all P < 0.05), except that of the CL (r = -0.181, P > 0.05). To a certain extent, Mann-Whitney U tests with Bonferroni correction for multigroup comparisons showed that the T2* values of the LLL, LML and RL could distinguish cirrhotic liver from healthy liver (all P < 0.05), whereas the T2* values of the CL could not (P > 0.05). Receiver operating characteristic analysis demonstrated that the T2* value of the RL could best distinguish cirrhosis from healthy liver, with an area under the receiver operating characteristic curve (AUC) of 0.713 among T2* values of the liver lobes, and that only the T2* value of the RL could distinguish Child-Pugh class C from A-B, with an AUC of 0.697 (all P < 0.05). CONCLUSION: The T2* value of the RL can be associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.

Evaluation of primary adrenal insufficiency secondary to tuberculous adrenalitis with computed tomography and magnetic resonance imaging: Current status.

As one kind of infectious diseases of adrenal gland, adrenal tuberculosis can result in a life-threatening disorder which is called primary adrenal insufficiency (PAI) due to the destruction of adrenal cortex. Computed tomography (CT) and magnetic resonance imaging (MRI) play significant roles in the diagnosis of this etiology of PAI based on the CT and MRI appearances of the adrenal lesions. In this mini-review, we intend to study the CT and MRI features of adrenal tuberculosis, which could be helpful to both endocrinologist and radiologist to establish a definitive diagnosis for adrenal tuberculosis resulting in PAI.

Patterns of portosystemic collaterals and diameters of portal venous system in cirrhotic patients with hepatitis B on magnetic resonance imaging: Association with Child-Pugh classifications.

BACKGROUND AND OBJECTIVE: To determine associations of patterns of portosystemic collaterals and diameters of portal venous system in cirrhotic patients with hepatitis B on magnetic resonance (MR) imaging with Child-Pugh classification. MATERIALS AND METHODS: Eighty-eight consecutive patients with cirrhosis resulting from chronic hepatitis B graded by Child-Pugh classifications were recruited and undergone MR portography. Patterns of the collaterals (presented as no collateral, isolated esophageal varices, and esophageal varices combined with other shunts), and diameters of portal venous system including portal vein (PV), left portal vein (LPV), right portal vein (RPV), splenic vein (SV) and superior mesenteric vein (SMV) were assessed statistically to determine associations of patterns of collaterals and diameters of the portal veins with Child-Pugh classification. RESULTS: From no collateral, to isolated esophageal varices, and to the varices combined with other shunts, the Child-Pugh classifications tended to increase (r=0.516, P<0.001). Diameters of PV, LPV, RPV, SV and SMV tended to increase from Child-Pugh A to B but decrease from B to C. Differences in diameter of LPV and SV were significant between Child-Pugh A-B and C (all P<0.05) while no differences in diameters of other portal veins were found (all P>0.05). For discriminating Child-Pugh A-B from C, either a cut-off LPV diameter of 8.98mm or SV diameter of 9.10mm achieved a sensitivity of 67%-70%, specificity of 51%-53%. CONCLUSION: Patterns of portosystemic collaterals and diameters of LPV and SV tend to be associated with Child-Pugh classifications of cirrhosis.

Platelet count combined with right liver volume and spleen volume measured by magnetic resonance imaging for identifying cirrhosis and esophageal varices.

AIM: To determine whether the combination of platelet count (PLT) with spleen volume parameters and right liver volume (RV) measured by magnetic resonance imaging (MRI) could predict the Child-Pugh class of liver cirrhosis and esophageal varices (EV). METHODS: Two hundred and five cirrhotic patients with hepatitis B and 40 healthy volunteers underwent abdominal triphasic-enhancement MRI and laboratory examination of PLT in 10(9)/L. Cirrhotic patients underwent endoscopy for detecting EV. Spleen maximal width (W), thickness (T) and length (L) in mm together with spleen volume (SV) and RV in mm(3) were measured by MRI, and spleen volume index (SI) in mm(3) was obtained by W × T × L. SV/PLT, SI/PLT and RV × PLT/SV (RVPS) were calculated and statistically analyzed to assess cirrhosis and EV. RESULTS: SV/PLT (r = 0.676) and SI/PLT (r = 0.707) increased, and PLT (r = -0.626) and RVPS (r = -0.802) decreased with the progress of Child-Pugh class (P < 0.001 for all). All parameters could determine the presence of cirrhosis, distinguish between each class of Child-Pugh class, and identify the presence of EV [the areas under the curve (AUCs) = 0.661-0.973]. Among parameters, RVPS could best determine presence and each class of cirrhosis with AUCs of 0.973 and 0.740-0.853, respectively; and SV/PLT could best identify EV with an AUC of 0.782. CONCLUSION: The combination of PLT with SV and RV could predict Child-Pugh class of liver cirrhosis and identify the presence of esophageal varices.

Liver lobe-based magnetic resonance diffusion-weighted imaging using multiple b values in patients with hepatitis B-related liver cirrhosis: association with the liver disease severity according to the Child-Pugh class.

OBJECTIVE: To determine the associations of liver lobe-based magnetic resonance diffusion-weighted imaging findings using multiple b values with the presence and Child-Pugh class of cirrhosis in patients with hepatitis B. METHODS: Seventy-four cirrhotic patients with hepatitis B and 25 healthy volunteers underwent diffusion-weighted imaging using b values of 0, 500, 800 and 1000 sec/mm2. The apparent diffusion coefficients of individual liver lobes for b(0,500), b(0,800) and b(0,1000) were derived from the signal intensity averaged across images obtained using b values of 0 and 500 sec/mm2, 0 and 800 sec/mm2, or 0 and 1000 sec/mm2, respectively, and were statistically analyzed to evaluate cirrhosis. RESULTS: The apparent diffusion coefficients for b(0,500), b(0,800) and b(0,1000) inversely correlated with the Child-Pugh class in the left lateral liver lobe, the left medial liver lobe, the right liver lobe and the caudate lobe (r=-0.35 to -0.60, all p<0.05), except for the apparent diffusion coefficient for b(0,1000) in the left medial liver lobe (r=-0.17, p>0.05). Among these parameters, the apparent diffusion coefficient for b(0,500) in the left lateral liver lobe best differentiated normal from cirrhotic liver, with an area under the receiver operating characteristic curve of 0.989. The apparent diffusion coefficient for b(0,800) in the right liver lobe best distinguished Child-Pugh class A from B-C and A-B from C, with areas under the receiver operating characteristic curve of 0.732 and 0.747, respectively. CONCLUSION: Liver lobe-based apparent diffusion coefficients for b(0,500) and b(0,800) appear to be associated with the presence and Child-Pugh class of liver cirrhosis.

Quantitative assessment of the presence and severity of cirrhosis in patients with hepatitis B using right liver lobe volume and spleen size measured at magnetic resonance imaging.

OBJECTIVE: To determine whether right liver lobe volume (RV) and spleen size measured utilizing magnetic resonance (MR) imaging could identify the presence and severity of cirrhosis in patients with hepatitis B. METHODS: Two hundred and five consecutive patients with clinically confirmed diagnosis of cirrhosis due to hepatitis B and 40 healthy control individuals were enrolled in this study and underwent abdominal triphasic enhanced scans using MR imaging. Spleen maximal width (W), thickness (T) and length (L), together with RV and spleen volume (SV), were measured utilizing MR imaging. Spleen multidimensional index (SI) was obtained by multiplying previously acquired parameters W×T×L. Then statistical assessment was performed to evaluate the ability of these parameters, including RV, SV, RV/SV and SI, to identify the presence of cirrhosis and define Child-Pugh class of this disease. RESULTS: SV and SI tended to increase (r = 0.557 and 0.622, respectively; all P<0.001), and RV and RV/SV tended to decrease (r = -0.749 and -0.699, respectively; all P<0.001) with increasing Child-Pugh class of cirrhosis. All the parameters, including RV, SV, RV/SV and SI, might be the indicators used to discriminate the patients with liver cirrhosis from the control group, and to distinguish these patients between Child-Pugh class A and B, between B and C, and between A and C (area under receiver operating characteristic curve [AUC] = 0.609-0.975, all P<0.05). Among these parameters, RV/SV was the best noninvasive factor for the discrimination of liver cirrhosis between Child-Pugh class A and B (AUC = 0.725), between A and C (AUC = 0.975), and between B and C (AUC = 0.876), while SI was the best variable to distinguish the cirrhosis patients from the control group (AUC = 0.960, P<0.05). CONCLUSION: RV/SV should be used to identify the severity of cirrhosis, while SI can be recommended to determine the presence of this disease.

Hepatic abnormal perfusion visible by magnetic resonance imaging in acute pancreatitis.

AIM: To study the prevalence and patterns of hepatic abnormal perfusion (HAP) visible by magnetic resonance imaging (MRI) in acute pancreatitis (AP). METHODS: Enhanced abdominal MRI was performed on 51 patients with AP. These patients were divided into two groups according to the MRI results: those with signs of gallstones, cholecystitis, common bile duct (CBD) stones or dilatation of the CBD on MRI and those without. The prevalence, shape and distribution of HAP in the two groups were analyzed and compared. The severity of AP was graded using the MR severity index (MRSI). The correlation between the MRSI and HAP was then analyzed. RESULTS: Of the 51 patients with AP, 32 (63%) showed at least one sign of gallbladder and CBD abnormalities on the MR images, while 19 (37%) showed no sign of gallbladder or CBD abnormalities. Nineteen patients (37%) had HAP visible in the enhanced images, including strip-, wedge- or patch-shaped HAP distributed in the hepatic tissue adjacent to the gallbladder and left and right liver lobes. There were no significant differences in the prevalence of HAP (χ (2) = 0.305, P = 0.581 > 0.05) or HAP distribution in the liver (χ (2) = 2.181, P = 0.536 > 0.05) between patients with and without gallbladder and CBD abnormalities. There were no significant differences in the MRSI score between patients with and without HAP (t = 0.559, P = 0.552 > 0.05). HAP was not correlated with the MRSI score. CONCLUSION: HAP is common in patients with AP and appears strip-, patch- or wedge-shaped on MRI. HAP on MRI cannot be used to indicate the severity of AP.

Spleen dynamic contrast-enhanced magnetic resonance imaging as a new method for staging liver fibrosis in a piglet model.

OBJECTIVE: To explore spleen hemodynamic alteration in liver fibrosis with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and to determine how to stage liver fibrosis with spleen DCE-MRI parameters. MATERIALS AND METHODS: Sixteen piglets were prospectively used to model liver fibrosis staged by liver biopsy, and underwent spleen DCE-MRI on 0, 5th, 9th, 16th and 21st weekend after modeling this disease. DCE-MRI parameters including time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI) and maximum slope of decrease (MSD) of spleen were measured, and statistically analyzed to stage this disease. RESULTS: Spearman's rank correlation tests showed that TTP tended to increase with increasing stages of liver fibrosis (r = 0.647, P<0.001), and that PEI tended to decrease from stage 0 to 4 (r = -0.709, P<0.001). MSD increased slightly from stage 0 to 2 (P>0.05), and decreased from stage 2 to 4 (P<0.05). MSI increased from stage 0 to 1, and decreased from stage 1 to 4 (all P>0.05). Mann-Whitney tests demonstrated that TTP and PEI could classify fibrosis between stage 0 and 1-4, between 0-1 and 2-4, between 0-2 and 3-4, or between 0-3 and 4 (all P<0.01). MSD could discriminate between 0-2 and 3-4 (P = 0.006), or between 0-3 and 4 (P = 0.012). MSI could not differentiate between any two stages. Receiver operating characteristic analysis illustrated that area under receiver operating characteristic curve (AUC) of TTP was larger than of PEI for classifying stage ≥1 and ≥2 (AUC = 0.851 and 0.783, respectively). PEI could best classify stage ≥3 and 4 (AUC = 0.903 and 0.96, respectively). CONCLUSION: Spleen DCE-MRI has potential to monitor spleen hemodynamic alteration and classify liver fibrosis stages.