【Abstract】ObjectiveTo investigate the relationship of magnetic resonance diffusion-weighted imaging (DWI) to histology in the patients of chronic viral hepatitis. MethodsThirty-five patients of chronic viral hepatitis who received liver biopsy and 10 healthy volunteers were included in this study. All of them underwent DWI on a 3.0T MRI device. Apparent diffusion coefficient (ADC) of the liver were measured respectively when b value were set as 100, 400, 600 and 800 s/mm2. Biopsy specimens were scored for fibrosis and necroinflammation according to the Knodell histology activity index (HAI). ResultsWhen b value was set as 800 s/mm2, statistical difference was showed between the fibrosis group and the nonfibrosis group, statistical difference was also shown among the different degrees of necroinflammation and fibrosis. ConclusionDWI is a valuable method for grading and staging of chronic viral hepatitis.
Objective To review the current status of magnetic resonance imaging (MRI) techniques in the evaluation of hepatic fibrosis. Methods The application and recent advances of various kinds of MRI techniques in evaluating hepatic fibrosis were summarized by literature review. Results The state-of-the-art of MRI evaluating of hepatic fibrosis included common contrast-enhanced MRI, double contrast-enhanced MRI, and various functional MRI techniques. Common contrast-enhanced MRI could detect morphological changes of the liver, but little value in phasing. Double contrast-enhanced MRI markedly increased the contrast to noise ratio. Except diagnosis liver fibrosis, functional MRI also could phase it by its serverity. Conclusion MRI techniques, especially those functional MRI techniques, are advancing very fast and have very great potentiality in both the diagnosis and severity assessment of hepatic fibrosis.
Objective To evaluate the imaging features of pancreatic neuroendocrine carcinoma （PNEC）. Methods The imaging data of 7 patients with PNECs proved by surgery and pathology in West China Hospital of Sichuan University from Jul. 2007 to Dec. 2012 were retrospectively analyzed. The boundary， density， and strengthening features of tumor were observed. Results Seven tumors were found in all patients with 2 in pancreatic head， body， and tail， respectively. There was 1 tumor in pancreatic body and tail too. Five tumors were with unclear boundary. Five tumors had hypodense enhancement and 2 had isodense enhancement. Two cases had distal pancreatic duct dilation. None of them had liver metastases or lymph node involvement. Conclusion PNEC has certain characteristics on imaging. It is difficult to distinguish diagnosis from pancreatic cancer.
ObjectiveTo compare the effectiveness of T2 weighted image (T2WI) and some compounded MRI techniques, including T2WI combined with magnetic resonance spectroscopy (T2WI+MRS), T2WI combined with diffusion weighted imaging (T2WI+DWI) and T2WI combined with dynamic contrast-enhancement [T2WI+(DCE-MRI)] respectively, with 1.5 T MR scanner in diagnosing prostate cancer through a blinding method. MethodsBetween March 2011 and April 2013, two observers diagnosed 59 cases with a blinding method. The research direction of radiologist A was to diagnose prostate cancer. The observers diagnosed and scored the cases with T2WI, T2WI+(DCE-MRI), T2WI+MRS, T2WI+DWI and compositive method respectively. The data were statistically analyzed with receiver operating characteristic (ROC) curve. ResultsAccording to the ROC curve, both observers got the sequence of area under curve (AUC) as T2WI+DWI > T2WI+(DCE-MRI) > T2WI+MRS > T2WI. On the basis of the result from observer A, the AUC from each technique was similar. The AUC of T2+DWI was slightly bigger than others. The specificity of single T2WI was the lowest; the sensitivity of T2WI was slightly higher. The AUC of the compositive method was marginally larger than T2WI+DWI. According to the result from observer B, the AUC of T2WI+DWI was obviously larger than the others. The AUC of single T2WI was much smaller than the other techniques. The single T2WI method had the lowest sensitivity and the highest specificity. The AUC of T2WI+DWI was slightly larger than the compositive method. The AUC of T2WI+(DCE-MRI), T2WI+MRS, single T2WI methods from observer A was obviously higher than those from the score of observer B. The AUC of T2WI+DWI from the two observers was similar. ConclusionThe method of combined T2WI and functional imaging sequences can improve the diagnosing specificity when a 1.5 T MR scanner is used. T2WI+DWI is the best method in diagnosing prostate cancer with least influence from the experience of observers in this research. The compositive method can improve the diagnosis of prostate cancer effectively, but when there are contradictions between different methods, the T2WI+DWI should be considered as a key factor.
Objective To investigate the neuropathogenesis of Adieprime;s pupil. Methods The neuroelectrophysiological and neuroimaging data of 42 patients with Adie's pupil (lightnear dissociation and segmental palsy of iris sphincter) were retrospectively analyzed. There were 37 patients with unilateral pupil dilation and 5 patients with bilateral pupil dilation. Cranial magnetic resonance imaging (MRI, 23 patients), Cranial CT scanning (1 patient), nerve conduction velocity (NCV, 14 patients), limb electromyogram (EMG, 5 patients), both lower extremities EMG (9 patients), visual evoked potential (VEP, 18 patients), somatosensory evoked potential (SEP, 11 patients) and electroencephalograms (EEG,5 patients) were performed on some of those patients. Results Central nervous system midline anatomic variations or minor lesions were found in 13/23 cases of MRI/CT imaging. Slowed sensory NCV and multiple sensorymotor peripheral nerve damages were evident in 6/14 cases of the NCV/EMG assay. 5/18 patients showed prolonged latency of VEP P100. 2/11 cases showed peripheral nerve damage in SEP recording, and 1/5 cases showed abnormal EEG. Conclusion Peripheral nerve damage may be an important pathogenesis of Adie's pupil, while the central nervous system damage is also involved in its pathogenesis.
Objective To investigate the situation and prospect of local recurrence of rectal cancer by using CT and MRI. Method Relevant references about the imaging diagnosis of local recurrence of rectal cancer， which were published domestic and abroad in recent years， were collected and reviewed. Results In the diagnosis of local recurrence of rectal cancer， the sensitivity of CT was higher than that of MRI， while the specificity and accuracy were not. Perfusion CT， dynamic contrast-enhanced MRI， and diffusion weighted imaging were valuable in diagnosing local recurrence of rectal cancer， as new diagnostic techniques. Conclusion Both CT and MRI are important and valuable methods in diagnosing for local recurrence of rectal cancer.
ObjectiveTo comparatively analyze the image features of tumorous acute pancreatitis (T-AP) and non-tumorous acute pancreatitis (NT-AP). MethodsSixteen cases of histopathologically proven pancreatic tumors inducing acute pancreatitis and 30 cases of non-tumorous acute pancreatitis were collected, and studied their CT and MRI features. ResultsThere were 16 cases (100%) with focal nodules or masses in T-AP group and none in NT-AP group. The average innerdiameter of main pancreatic ducts in T-AP group was (9.6±6.8) mm, in which 14 cases (87.5%) were dilated. And the average innerdiameter of main pancreatic ducts in NT-AP group was (2.9±0.9) mm, in which 7 cases (23.3%) were dilated. The cases of sinistral portal hypertension (SPH), accompanying cholelithiasis and lymphadenosis between the two groups were 10 (62.5%), 3 (18.8%), 14 (87.5%), and 1 (3.4%), 25 (83.3%), 30 (100%), respectively. The occurrence of manifestation of focal nodules or masses, dilated main pancreatic ducts, SPH, and accompanying cholelithiasis were significantly different (P=0.000) between T-AP and NT-AP groups. While, the differences in enhancement pattern and the occurrence of lymphadenosis between the two groups were not significant (P > 0.05). ConclusionThe image features of T-AP are various. The application of CT and MRI could provide effective diagnostic guidelines for patients with T-AP.
ObjectiveTo conduct a meta-analysis comparing the accuracy of artificial intelligence (AI)-assisted diagnostic systems based on 18F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT) and structural MRI (sMRI) in the diagnosis of Alzheimer's disease (AD). MethodsOriginal studies dedicated to the development or validation of AI-assisted diagnostic systems based on 18F-FDG PET/CT or sMRI for AD diagnosis were retrieved from the Web of Science, PubMed, and Embase databases. Studies meeting the inclusion criteria were collected, and the risk of bias and clinical applicability of the included studies were assessed using the PROBAST checklist. The pooled sensitivity, specificity, and area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated using a bivariate random-effects model. ResultsTwenty-six studies met the inclusion criteria, yielding a total of 38 2×2 contingency tables related to diagnostic performance. Specifically, 24 contingency tables were based on 18F-FDG PET/CT to distinguish AD patients from normal cognitive (NC) controls, and 14 contingency tables were based on sMRI for the same purpose. The meta-analysis results showed that for 18F-FDG PET/CT, the AI-assisted diagnostic systems had a pooled sensitivity, specificity, and SROC-AUC of 89% (95%CI 88% to 91%), 93% (95%CI 91% to 94%), and 0.96 (95%CI 0.93 to 0.97), respectively. For sMRI, the AI-assisted diagnostic systems had a pooled sensitivity, specificity, and SROC-AUC of 88% (95%CI 85% to 90%), 90% (95%CI 87% to 92%), and 0.94 (95%CI 0.92 to 0.96), respectively. ConclusionAI-assisted diagnostic systems based on either 18F-FDG PET/CT or sMRI demonstrated similar performance in the diagnosis of AD, with both showing high accuracy.
Objective To observe the changes of visual pathway of central nervous system in patients with glaucoma.Methods Thirty-five subjects were enrolled in this prospective study. There were seven patients of chronic primary angle closure glaucoma with bilateral visual field defects, 12 patients of primary open angle glaucoma with bilateral visual field defects, and 16 normal subjects. GE Signa HD 1.5 T magnetic resonance scanners and head eight phased array were used. The mean fractional anisotropy (FA) and the mean average diffusion coefficient (DCavg) of white matter tracts in visual pathway of bilateral optic nerve, optic chiasma, bilateral optic tract，bilateral optic radiation were measured by diffusion tensor imaging, meanwhile the white matter tracts were reconstructed by fiber tracking system. The volumes of lateral geniculate body were measured by coronal proton density weighted magnetic resonance imaging.Results The differences of FA among bilateral optic nerve, optic chiasma, bilateral optic tract，bilateral optic radiation were statistically significant (F=25.985，20.626，12.262，22.399，21.708，24.994，22.774；P＜0.05). There was no difference of DCavg among bilateral optic nerve, optic chiasma, bilateral optic tract，bilateral optic radiation（F=2.097，2.178，0.530，0.983，0.608, 0.866, 1.504；P＞0.05）. The differences of volume of lateral geniculate body among three groups were statistically significant （F=18.631，17.274；P＜0.05）. Conclusion There is degeneration in visual pathway of central nervous system in patients with glaucoma.
Objective To investigate the imaging features of idiopathic hepatic arteriovenous malformation（IHAVM） on multi-detector row spiral CT (MDCT) and magnetic resonance imaging (MRI). Methods Nineteen patients with IHAVM between January 2009 and June 2010 were included for retrospective analysis of the imaging findings on MDCT (n=9) and MRI (n=10), especially the imaging features of IHAVM on contrast-enhanced dynamic scans. Results All IHAVM lesions in 9 patients were isodense in plain scan of MDCT, and showed marked small nodular or linear enhancement with similar intensity to vascular enhancement in arterial phase, and the enhancement continued to persist to portal phase but with reduced enhancement degree. Early visualization of venous tributaries in arterial phase was present in 4 cases, and wedge-shaped or lamellar transient hepatic parenchyma enhancement in arterial phase in the edge of the lesion was observed in 6 cases. In 10 patients with MRI scan, the enhancement patterns of IHAVM were quite similar to the findings on MDCT, with early visualization of venous tributaries in arterial phase in 5 cases and wedge-shaped transient hepatic parenchyma enhancement in arterial phase in the edge of the IHAVM lesion in 7 cases. Conclusion Contrast-enhanced multi-phase MDCT and MRI scans can depict the morphologic and hemodynamic characteristics of IHAVM, thus they are very valuable for the diagnosis of IHAVM.