Objective To review the principles and techniques of CT perfusion imaging and its applications in the imaging diagnosis of abdominal disorders. Methods All the relevant literatures were reviewed. The principles and techniques of CT perfusion imaging were described and summarized in detail. The functional information of a target abdominal organ (e.g. the liver and pancreas) revealed by CT perfusion imaging, such as hemodynamics and microcirculation status, was also evaluated. Results In addition to the morphologic information, CT perfusion imaging can also provide functional information about the circulation parameters of target abdominal organs. Moreover, such functional information can be generated for the neovasculature and microcirculation of tumor lesions of abdominal organs, which is very helpful for not only the diagnosis, but also the evaluation of tumor invasiveness and response to treatment. Conclusion CT perfusion imaging offers an effective method for studying abdominal disorders by providing functional information that is quite useful for the differential diagnosis and assessment of therapeutic response.
Objective To review the CT appearances and important differential diagnoses of various primary and secondary mesenteric neoplasms. Methods By describing the mesenteric anatiomy and major routes for the dissemination of metastatic mesenteric tumors, the article presents both the common and rare types of various primary and secondary mesenteric neoplasms, and addresses the characteristic CT appearances and important aspects of the differential diagnosis. Results CT study, especially the multislice spiral CT (MSCT), along with the clinical history and other related information, can nicely depict various mesenteric tumors and well differentiate them from infectious, inflammatory or vascular processes affecting the mesentery. Conclusion CT is the imaging method of choice for the evaluation of tumors of small bowel mesentery.
Objective To introduce the imaging modalities used for the evaluation of postoperative complications of orthotopic liver transplantation (OLT) and to present the imaging findings of these complications. Methods The literatures related to the imaging methods and imaging manifestations of OLT complications were reviewed. Results Ultrasound was the initial imaging technique used for the detection of complications in the early postoperative period. Spiral CT and MRI yielded more accurate and comprehensive evaluation of postoperative complications in later stage. So far, there had been no specific imaging findings to suggest rejection reaction. The spectrum of imaging manifestations of OLT complications, such as vascular complications, biliary complications, liver parenchymal complications, and so on, were summarized and illustrated. Conclusion Imaging examination (especially ultrasound, spiral CT and MRI ) plays an important role in the evaluation of postoperative complications of OLT.
Objective To summarize the research status and progress of imaging diagnosis of periampullary carcinoma. Methods The literatures on imaging diagnosis of periampullary carcinoma were reviewed. Results At present, the commonly used imaging diagnosis methods for periampullary carcinoma mainly include ultrasound, CT, MRI, and endoscopic retrograde cholangiopancreatography. Some other new imaging techniques had also been applied in the diagnosis and evaluation of periampullary carcinoma. Conclusions Different imaging methods have their own advantages and disadvantages in the diagnosis of periampullary carcinoma. Therefore, the detection rate and diagnostic accuracy of periampullary carcinoma can be improved by rational selection of imaging techniques or combined application of multiple techniques.
ObjectiveTo evaluate the diagnostic value of CT, MRI, and magnetic resonance cholangiopancreatography (MRCP) in the localization and qualitative diagnosis of biliary obstruction.MethodsA total of 80 patients with biliary obstruction in our hospital from January 2018 to June 2020 were retrospectively collected. The patients were all examined by CT, MRI, and MRCP. The imaging images of all patients were interpreted by two radiologists with more than 5 years of working experience. Taking the results of operation and histopathology as the gold standard, the diagnostic value of CT, MRI+MRCP, CT+MRI+MRCP in the localization and qualitative diagnosis of biliary obstruction lesions were evaluated.ResultsCompared with the location results of surgery and histopathology, the coincidence rates of CT+MRI+MRCP and MRI+MRCP were higher than that of CT (P<0.05), but there was no significant difference between CT+MRI+MRCP and MRI+MRCP (P>0.05); compared with the benign and malignant results of surgery and histopathology, the coincidence rates of CT, CT+MRI+MRCP and MRI+MRCP were close, and there was no statistical significance among them (P>0.05).ConclusionsMRI+MRCP and CT+MRI+MRCP have the same value in the localization and qualitative diagnosis of biliary obstruction. However, MRI+MRCP have the advantages ofnon-radiation or contrast media, it is more suitable for patients who are worried about the impact of radiation, have contrast media allergy or renal insufficiency.
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 CT manifestations of acute pancreatitis (AP) and its complications and to evaluate the imaging modalities for staging the severity of AP. Methods Literatures on CT manifestations of AP and its complications and severity staging of AP were reviewed.Results CT has shown an early overall detection rate of 90% for pancreatic necrosis with close to 100% sensitivity 4 days after episode. The CT severity index has shown a bly positive correlation with the development of local complications and mortality of AP.Conclusion Contrastenhanced CT is the imaging modality of choice to help detect pancreatic necrosis, stage the severity of the inflammatory processes, and depict local complications.
Objective To summarize the recent application progress of dual-energy CT in pancreatic imaging. Methods The domestic and international published literatures related to the application of dual-energy CT in pancreatic imaging in recent years were collected and reviewed. Results Dual-energy CT could provide the morphological image and function information of tissues and organs simultaneously. At present, the clinical application of dual-energy CT in pancreatic imaging included low tube voltage technology, iodine overlay, virtual non-enhanced imaging, and monoenergetic imaging. Conclusion Dual-energy CT could contribute to detecting pancreatic lesions, reducing radiation dose, and improving image quality in pancreatic imaging.
【Abstract】Objective To summarize the principle and clinical applications of 31phosphorus MR spectroscopy（31pMRS）. Methods Literatures about 31PMRS in liver were reviewed and analyzed. Results Abnormalities of 31PMRS were found in patients of hepatitis, liver cirrhosis, liver tumor，obstructive jaundice and patients after liver transplantation. Evaluation of 31PMRS is important in diagnosis and treatment of many hepatic diseases. Conclusion As a noninvasive protocol for analyzing the energetic metabolism and biomedical changes in cellular level of living liver, 31PMRS has a wide clinical application.
Objective To investigate the value of MR diffusion-weighted imaging (DWI) in differentiating pancreatic carcinoma from chronic focal pancreatitis on 3.0 T MR system. Methods Thirteen patients with proved pancreatic carcinoma, 7 patients with confirmed chronic focal pancreatitis, and 14 healthy volunteers, were included in this study. MR examination including the routine abdomen scanning protocol and DWI was performed for both patients and volunteers. The SE-EPI sequence and ASSET technique were used for DWI. The b values of 400, 600, 800 and 1 000 s/mm2 were selected to acquire the DWI. The corresponding apparent diffusion coefficient (ADC) values were measured in each designated region of interest and statistically analyzed. Results ①DWI of the healthy volunteers showed intermediate signals of pancreas. ②DWI of pancreatic tumor masses showed homogenous high signal intensity relative to the surrounding pancreatic tissue with clear boundary. Under different b values, the tumor ADC values were (1.63±0.235)×10-3 mm2/s, (1.42±0.126)×10-3mm2 /s, (1.36±0.170)×10-3 mm2 /s and (1.26±0.178)×10-3 mm2 /s respectively, which were significantly lower than those of non-tumor region 〔(2.11±0.444)×10-3 mm2 /s, (1.83±0.230)×10-3 mm2 /s, (1.81±0.426)×10-3 mm2 /s, (1.60±0.230)×10-3 mm2 /s〕 and of the normal pancreas 〔(1.85±0.350)×10-3 mm2 /s, (1.69±0.290)×10-3 mm2 /s, (1.67±0.268)×10-3 mm2 /s, (1.42±0.221)×10-3 mm2 /s〕， P＜0.05. ③DWI of chronic focal pancreatitis showed inhomogeneous slightly hyper-intense signal with blurring borders. Under different b values, the ADC values of the inflammatory masses of chronic pancreatitis were (169±0.150)×10-3 mm2 /s, (1.56±0.119)×10-3 mm2 /s, (1.59±0.172)×10-3 mm2/s and (1.35±0.080)×10-3 mm2 /s respectively, which were higher than those of pancreatic carcinoma. When b value was set to 800 s/mm2 , the difference in ADC values between pancreatic carcinoma and chronic focal pancreatitis was statistically significant (P＜0.05). Conclusion MR DWI can clearly depict the tumor mass of pancreatic carcinoma. In addition, the measurement of ADC values can provide useful information for the differential diagnosis between pancreatic carcinoma and chronic focal pancreatitis.