Early assessment of acute kidney injury in severe acute pancreatitis with multimodal DWI: an animal model.

OBJECTIVES: To evaluate the feasibility of multimodal diffusion-weighted imaging (DWI) for detecting the occurrence and severity of acute kidney injury (AKI) caused by severe acute pancreatitis (SAP) in rats. METHODS: SAP was induced in thirty rats by the retrograde injection of 5.0% sodium taurocholate through the biliopancreatic duct. Six rats underwent MRI of the kidneys 24 h before and 2, 4, 6, and 8 h after this AKI model was generated. Conventional and functional MRI sequences were used, including intravoxel incoherent motion imaging (IVIM), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DTI). The main DWI parameters and histological results were analyzed. RESULTS: The fast apparent diffusion coefficient (ADC) of the renal cortex was significantly reduced at 2 h, as was the fractional anisotropy (FA) value of the renal cortex on DTI. The mean kurtosis (MK) values for the renal cortex and medulla gradually increased after model generation. The renal histopathological score was negatively correlated with the medullary slow ADC, fast ADC, and perfusion scores for both the renal cortex and medulla, as were the ADC and FA values of the renal medulla in DTI, whereas the MK values of the cortex and medulla were positively correlated (r = 0.733, 0.812). Thus, the cortical fast ADC, medullary MK, FADTI, and slow ADC were optimal parameters for diagnosing AKI. Of these parameters, cortical fast ADC had the highest diagnostic efficacy (AUC = 0.950). CONCLUSIONS: The fast ADC of the renal cortex is the core indicator of early AKI, and the medullary MK value might serve as a sensitive biomarker for grading renal injury in SAP rats. CLINICAL RELEVANCE STATEMENT: The multimodal parameters of renal IVIM, DTI, and DKI are potential beneficial for the early diagnosis and severity grading of renal injury in SAP patients. KEY POINTS: • The multimodal parameters of renal DWI, including IVIM, DTI, and DKI, may be valuable for the noninvasive detection of early AKI and the severity grading of renal injury in SAP rats. • Cortical fast ADC, medullary MK, FA, and slow ADC are optimal parameters for early diagnosis of AKI, and cortical fast ADC has the highest diagnostic efficacy. • Medullary fast ADC, MK, and FA as well as cortical MK are useful for predicting the severity grade of AKI, and the renal medullary MK value exhibits the strongest correlation with pathological scores.

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.

[Assessment of global left and right ventricular function with 64 multi-detector row computed tomography in healthy adults].

To evaluate the global left and right ventricular function and establish the CT reference data of global ventricular function parameters in normal people, 56 normal subjects (male, 28 cases; female, 28 case) were scanned with retrospective ECG gated 64-detector row CT. Ten time-phases in the cardiac cycle were reconstructed and short-axis images were acquired. On the cardiac analysis software, endo-cardium and epi-cardium of left and right ventricle were delineated and global function parameters were calculated. Left and right ventricular end-diastolic volume (LV/RVEDV), end-systolic volume (LV/RVESV), stroke volume (LV/RVSV), and wall mass (LV/RVWM) were significantly greater (P < 0.05) in men than in women, but cardiac output (LV/RVCO) and ejection fraction (LV/RVEF) exhibited no difference in women and men. In man group and woman group, LVWM was greater than RVWM (P < 0.01). LVESV, RVESV and body mass Index (BMI) were shown to have significant negative-correlation; the correlation coefficient = -0.54 and r = -0.53. LV/RVSV, LV/RVEF and BMI were noted to have significant positive-correlation; the correlation coefficients were 0.87/0.97 and 0.69/0.62, respectively. The normal global left and right ventricular functions differ significantly according to gender and body size.

[Assessment of regional left ventricular function with 64 multi-detector row computed tomography].

To evaluate the regional left ventricular function (LVF) and to establish the reference data of LVF parameters in the normal people with retrospective ECG gating 64-detector row CT, ten time phases in the cardiac cycle were reconstructed. Scanning was performed on 42 normal adult, and short axis images of the left ventricular were acquired. Endo-cardium and epi-cardium were delineated along with function parameters based on the cardiac analysis software. End-systolic thickness (EST) was thicker than end-diastolic thickness (EDT) (P<0.05). EDT and EST increased, but thickness decreased from apical, mid-ventricular to basal segments. Statistically significant difference was noted between mid-ventricular and basal segments (P<0.05). EDT, EST, thickness and motion of anterior, lateral and inferior segments were greater than those of septal segments in the same ventricular slices (P<0.05). 64-detector row CT could depict the regional LVF accurately. The LVF parameters of normal adults might be useful in diagnosing abnormal left ventricular function.