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.
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.
ObjectiveTo explore the value of 3.0 T MRI functional imaging in differential diagnosis of radiation brain injury and recurrence of glioblastoma multiforme.MethodsFrom March 2017 to January 2018, 31 patients diagnosed with brain glioblastoma multiforme in Peking University International Hospital were collected continuously, including 14 cases of tumor recurrence and 17 cases of radiation-induced brain injury. All the patients routinely underwent conventional MRI head scan, three-dimension arterial spin labeling (3D-ASL), dynamic susceptibility contrastperfusion weighted imaging (DSC-PWI), and enhanced MRI scan sequence; related parameters were recorded and compared.ResultsCerebral blood flow (CBF) value of abnormal enhanced area in the recurrence group was significantly higher than that in the brain injury group with 3D-ASL scan (t=3.016, P=0.005), and no difference was found in edema area between the two groups (P>0.05). In the recurrence group, CBF value of abnormal enhanced area was significantly higher than that of the normal area (t=2.628, P=0.014); however, there was no significant difference in the CBF value between the abnormal enhancement foci and the normal areas in the radiation brain injury group (P>0.05). Relative cerebral blood volume (rCBV) ratio (t=2.894, P=0.007) and relative cerebral blood volume (rCBF) ratio (t=2.694, P=0.012) of abnormal enhanced area, as well as rCBV ratio (t=2.622, P=0.013) and rCBF ratio (t=2.775, P=0.010) of edema area in the recurrence group were significantly higher than those in the brain injury group with DSC-PWI scan. No differences were found in relative mean transit time (rMTT) ratio and relative time to peak (rTTP) ratio between the two groups (P>0.05). In the brain injury groupr, CBV ratio (t=2.921, P=0.008) and rCBF ratio (t=3.100, P=0.004) of abnormal enhanced area were significantly higher than those of the edema area, and no difference was found in rMTT ratio or rTTP ratio (P>0.05). In the recurrence group, no difference was found in all focal parameters between abnormal enhanced area and edema area (P>0.05). In diagnosis value analysis, the areas under the curve of CBF in 3D-ASL scan, and rCBF ratio, rCBV ratio in DSC-PWI scan were 0.752, 0.675, and 0.645, respectively; the cut-off values were 34.59, 1.48, and 1.67, respectively; the sensitivities were 79.2%, 61.5%, and 58.3%, respectively; and the specificities were 44.4%, 32.8%, and 22.4%, respectively.ConculsionThe diagnostic value of functional MRI imaging in distinguishing glioblastoma multiforme recurrence and radiation-induced brain injury is high recommendated; further research and clinical application should be needed.
Abstract： Objective To assess the effects of simultaneous antegrade/retrograde cardioplegia (SARC) on myocardial perfusion and energy metabolism in ischemic myocardium using magnetic resonance imaging (MRI). Methods After the hearts were harvested from 18 domestic pigs, left anterior descending artery, aorta, anterior ascending cardiac vein and coronary sinus were cannulated to establish the perfusion routes. 6 hearts were used to assess the effects of SARC on myocardial perfusion. Energy metabolism was observed in the other 12 pig hearts. MRI was used to monitor the distribution of contrast agent (gadoliniumdiethylenetriamine penlaacetic acid, Gd-DTPA) in the myocardium after its injection through arterial and retrograde perfusion routes. The efficacies in sustaining myocardial perfusion and energy metabolism were evaluated by using phosphorus-31 magnetic resonance spectroscopy (31P MRS) during antegrade cardioplegia (AC) and SARC respectively. Results It was found that injection of Gd-DTPA into the aorta during AC did not result in signal increase in the ischemic myocardium on MRI. During SARC, however, Gd-DTPA was found in the ischemic region as well as in the other regions, no matter if it was given into the aorta or into the coronary sinus. Moreover,31P spectra showed that occlusion of LAD during AC resulted in severe decrease of the levels of phosphocreatine (PCr) and adenosine triphosphate (ATP), while the level of inorganic phosphate (Pi) increased in LAD-support myocardium. The abnormal metabolic changes were completely abolished by use of SARC. Conclusion It is concluded that SARC can deliver cardioplegic solution to the myocardium distal to a coronary occlusion and can sustain normal energy metabolism in the jeopardized myocardium.
Objective To detecte the pathogenetic mechanism of cortical deficit in persons with strabismic amblyopia by blood oxygenation level dependent-functional magnetic resonance imaging(BOLD-fMRI)． Methods The data of BOLD-fMRI of occipital visual cortex in 11 persons with strabismic amblyopia and 8 healthy ones were collected by 1．5T MRI system．The results of binocular pixel exponent in strabismic amblyopia group was compared with that in the normal group and the result of and average activation of cortical neuron in strabismic amblyopia group was analyzed.Results The binocular pixel exponent was lower in the strabismic amblyopia group(14．13％±4．55％)than that in the normal group(47．82％±5．34％)(PConclusions The reduction of cortical binocular cells and the undersampling and coding of higher-spatial-frequency components of visual stimuli may be related to the strabismic amblyopia．BOLD-fMRI may provide a new path to detecte the pathoffenetic mechanism of cortical deficit in people with strabismic amblyopia. (Chin J Ocul Fundus Dis，2004，20：19-22)
Objective To assess value and limitations of non-invasive methods in assessing liver fibrosis．Methods By summarized current situation and advancement of serum fibrotic markers, ultrasound, CT and MRI in assessing liver fibrosis, we investigated their value and limitations. Results In addition to diagnosis, non-invasive methods of assessing liver fibrosis assess severity of liver fibrosis. For liver fibrosis, however, non-invasive methods can not monitor effectively reaction to therapy and progression. Conclusion Non-invasive methods play important roles in diagnosis and assessing severity of liver fibrosis, and reduce the need of liver biopsy.
Objective To investigate the depiction rate of normal cisterna chyli and thoracic duct by nonenhanced MR lymphography and to describe their appearances on MR imaging. Methods Special MR hydrography sequence was added to the MR imaging protocols of 112 patients undergoing MR examination of the thorax and upper abdomen. MR imaging sequences included: ①Respiratory-gated HASTE T2W sequence; ②Breath-hold FLASH T1W sequence; ③Respiratory-gated TSE 3D T2W sequence (3D MR hydrography sequence) in coronal plane. One hundred cases who met the inclusion criteria were included into the study for observation of the depiction rate, location and morphology of cisterna chyli and thoracic duct. Results On TSE 3D T2W imaging： ①Cisterna chyli was visualized in 71/100 (depiction rate 71.0%), morphologically including single-tube type 43.7% (31/71), bifurcation type (2-3 tubes) 23.9% (17/71), plexus type 32.4% (23/71). Average length of the cisterna chyli was 4.5 cm. ②The depiction rate of the lower segment of thoracic duct was 57.0% (57/100), average ductal diameter was 0.23 cm. ③The depiction rate of upper segment of the thoracic duct was 31.0% (31/100). Conclusion As a noninvasive method for depicting the lymphatic system, nonenhaced MR lymphography (TSE 3D T2W sequence) demonstrated a high depiction rate for cisterna chyli and lower thoracic duct. Combined with axial images of HASTE and FLASH sequences, the location and morphology of these larger lymphatic ducts can be defined.
ObjectiveTo systematically review the overall diagnostic efficacy of Gd-EOB-DTPA-enhanced MRI in differentiating dysplastic nodules (DNs) and hepatocellular carcinoma (HCC), exploring whether the hepatobiliary phase can effectively improve diagnostic accuracy. MethodsThe PubMed, Embase, Web of Science, Cochrane Library, CNKI, WanFang Data, and CBM databases were searched from January 1998 to March 2023 to identify original studies on Gd-EOB-DTPA-enhanced MRI for the differential diagnosis of DNs and HCC. Two investigators independently performed literature screening, extraction of data features and quality assessment. Meta-analysis was performed using Stata 17.0 and Meta-disc1.4 software. ResultsA total of 14 papers were included in this meta-analysis, including 375 DNs and 653 HCC. The results of meta-analysis showed that, in the multiparametric diagnostic sequence, the pooled Sen, Spe, PLR, NLR and AUC were 0.95 (95%CI 0.87 to 0.98), 0.95 (95%CI 0.91 to 0.97), 18.57 (95%CI 9.64 to 35.78), 0.06 (95%CI 0.02 to 0.14) and 0.98 (95%CI 0.97 to 0.99), respectively. ConclusionGd-EOB-DTPA-enhanced MRI has a good differential diagnostic value for DNs and HCC. Hepatobiliary phase imaging also greatly compensates for the diagnostic deficiency of dynamic enhancement with low sensitivity for early HCC.
Objective To investigate the value of new double-phasic MR contrast agent (gadobenate dimeglumine， Gd-BOPTA) in diagnosis of hepatocellular carcinoma (HCC) with correlation of pathology. Methods MRI scan was performed on 33 patients suspected of having focal liver lesions by CT or ultrasonography. The MRI scan protocol included routine axial T1WI and T2WI, coronal T2WI and 3D-MRCP, Gd-BOPTA enhanced 3D gradient-echo sequence of T1W (LAVA sequence) acquiring dynamic data at 15 s, 55 s and 90 s respectively, delayed LAVA acquisition at 5 min, 10 min, and at 40 min, 80 min respectively. Surgical specimen was collected for pathological analysis. Results Surgery confirmed the diagnosis of HCC in 21 patients with 27 lesions. The sensitivity, specificity and accuracy of MR imaging with combined phases (including hemodynamic phase and hepatobiliary phase) were 92.9%,93.3%, 92.9% respectively. ①In the hemodynamic phase: 22 lesions showed early enhancement in arterial phase, fast “washout” in portal venous phase, and hypointense in delayed phase. Four lesions showed slight enhancement, while 1 lesion showed no enhancement in all hemodynamic phases. ②In the hepatobiliary phase: 23 lesions showed homogeneous hypointensity compared to the enhanced liver background, but 4 lesions (3 well-differentiated and 1 moderately-differentiated) had patchy or dot-like slightly hyperintense areas scattered within the lesions. Pathologically cholestatic changes of tumor cells were observed and bile-containing small ducts were present. Conclusion Gd-BOPTA enhanced MRI can both depict the hemodynamic characteristics and reflect the absence of normal hepatocyte function in HCC lesions, thus contributing greatly to the diagnosis of HCC.