ObjectiveTo introduce the technique of threedimensional portal venography of multidetector row spiral CT and its clinical application in the evaluation of the portosystemic collateral shunts of liver cirrhosis. MethodsAll relevant literatures were retrospectively reviewed on the application of twodimensional and threedimensional reconstruction techniques such as MIP, SSD, VRT of multidetector row spiral CT to demonstrate the collateral vessels of liver cirrhosis.ResultsThe distribution, pathway and anatomy of portosystemic collateral vessels were well shown by multidetector row spiral CT portal venography. Conclusion Multidetector row spiral CT portal venography provides excellent depiction of the anatomic characteristics of the collateral shunts and enables the continuous tracing of vascular structures, thus it is very helpful in the imaging evaluation of the collateral vessels of liver cirrhosis.
ObjectiveTo introduce the new nomenclature scheme of the International Working Group (1995) on hepatic nodules, and summarize the imaging features of various hepatic nodules in light of their pathological characteristics, and evaluate the diagnostic values of various imaging facilities.MethodsUltrasound, computed tomography(CT), magnetic resonance imaging(MRI), and angiographic CT were reviewed and introduced.ResultsMany of these types of hepatic nodules play a role in the de novo and stepwise carcinogenesis of hepatocellular carcinoma(HCC) in the following steps: regenerative nodule, lowgrade dysplastic nodule, highgrade dysplastic nodule, small HCC, and large HCC. Accompanying such transformations, there are significant alterations in the blood supply and perfusion of these hepatic nodules.ConclusionModern stateoftheart medical imaging facilities can not only delineate and depict these hepatic nodules, but also provide important clues for the characterization of focal hepatic lesions in most cases, thus facilitating the early detection, diagnosis and management of HCC in its early stage.
Objective To summarize the principle and application of functional MR imaging of pancreatic carcinoma and chronic mass-forming type pancreatitis. Methods Articles about diffusion-weighted imaging (DWI), magnetic resonance spectrum imaging (MRSI) and dynamic contrast-enhanced MR imaging of pancreatic carcinoma and chronic pancreatitis were reviewed and analyzed. Results Functional MR imaging could reflected the differences in molecules diffusion, metabolism and tissue perfusion between pancreatic carcinoma and chronic pancreatitis. Conclusion As a non-invasive protocol, functional MR imaging can provide useful information in differential diagnosis between chronic mass-forming type pancreatitis and pancreatic carcinoma.
【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 spiral CT manifestations of the collateral circulation pathways resulting from splenic vein occlusion (SVO) duo to pancreatic diseases. Methods The CT imaging and clinical data of 33 cases of pancreatic disease with SVO, including 28 cases of pancreatic carcinoma, 3 cases of acute pancreatitis and 2 cases of chronic pancreatitis, were retrospectively analyzed.Results Tortuous and dilated vessels were observed in the areas between splenic hilum and gastric fundus and/or along the gastric greater curvature in all 33 cases. In isolated SVO cases, the short gastric vein (SGV, 86%)，coronary vein (CV, 79%)，gastroepiploic vein (GEV, 79%) and gastrocolic trunk (GCT, 57%) were varicose and dilated. While in nonisolated SVO，other collateral veins such as the right superior colic vein (RSCV, 37%），middle colic vein (MCV, 37%） and posterior superior pancreaticoduodenal vein (PSPDV, 21%） were seen as well. Conclusion The two predominant collateral pathways of SVO are ①SGV→gastric fundal veins→CV， and ②GEV→GCT→SMV. They have characteristic imaging features on spiral CT and are of clinical significance in both preoperative staging of pancreatic carcinoma and the evaluation of pancreatogenic segmental portal hypertension.
Objective To retrospectively assess the importance and imaging appearance of the signal intensity， the signal noise ratio (SNR), the contrast noise ratio (CNR) and enhancement patterns of early arterial phase in diagnosis and differential diagnosis of small hepatic nodular lesions on MRI. Methods Conventional spin-echo T2W, 2D GRE T1W plain scan and Gd-enhanced 3D-VIBE multi-phasic (early arterial, late arterial and portal venous phase) acquisitions were performed for 68 consecutive patients with 102 lesions on MRI. Native T2W and 2D GRE T1W were acquired first, then 3D-VIBE fast scanning at early arterial, late arterial and portal venous phase respectively. The SNR, CNR, signal intensity and enhanced pattern of the nodular lesions appearances on plain scan and eariy arterial phase were carefully observed. Results There were hyperintense in 102 (100%) lesions in T2W and hypointense in 95 (93.1%) lesions in T1W in plain scan. There were differences among the SNR, CNR of hepatic cyst, cavernous hemangioma, neoplasm metastasis and small hepatocellular carcinoma in T2W (P＜0.05)，the highest SNR and CNR of lesions were hepatic cyst. The SNR of small hepatocellular carcinoma and the CNR of hepatic cyst were highest in all the type diseases in T1W, there was significantly difference as compared with the other type diseases (P＜0.05). The enhancement rate of small hepatic nodular lesions was 76.5% in early arterial phase. The enhancement rate of small hepatocellular carcinoma and hepatic metastasis were 100% and 87.9% respectively. The non-enhancement rate of hepatic cyst were 100%. The common enhancement patterns of early arterial phase were peripheral enhancement which were 36 lesions (35.3%). The even enhancement and uneven enhancement were 22 lesions (21.6%) and 20 lesions (19.6%) respectively. Conclusion Qualitative and quantitative evaluation of MR signal intensity combined with the enhancement patterns of early arterial phase will help for qualitation and differential diagnosis of small hepatic nodular lesions on MRI.
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.
Objective To investigate the diagnostic value of CT scanning and MR imaging on acute cholecystitis. Methods The CT or MR imaging data of 21 patients with proved acute cholecystitis were retrospectively reviewed. Eleven patients were examined with contrast-enhanced multi-detector-row spiral CT scanning and other 10 cases underwent contrast-enhanced MR imaging. Results Nineteen patients showed obscure gallbladder outlines （90.5%）. The gallbladder wall demonstrated even thickening in 15 patients （71.4%） and irregular thickening in 6 cases （28.6%）. All patients showed inhomogeneous enhancement of the gallbladder wall （100%）. The bile was hyper-dense or hyper-intense on T1W image in 11 cases （52.4%）. Ten cases had free peri-cholecystic effusion （47.6%）, and 16 cases had peri-cholecystic adhesive changes or fat swelling （76.2%）. Patchy or linear-like transient enhancement of the adjacent hepatic bed in the arterial phase was seen in 16 cases （76.2%）. Twelve patients developed pleural effusion, or ascites, or both （57.1%）. Gallbladder perforation complicated with peritonitis was seen in one case, micro-abscess formation and pneumocholecystitis was observed in another case, and one case had gallbladder diverticulum. Conclusion Wall blurring, pericholecystic adhesion or fat edema, and transient enhancement of adjacent hepatic bed in the arterial phase are the imaging findings specifically associated with acute cholecystitis, which are readily appreciated on contrast-enhanced multi-phasic CT and MR scanning.
ObjectiveTo discuss the feasibility and accuracy of distal femoral patient-specific cutting guide in total knee arthroplasty (TKA) based on knee CT and full-length X-ray film of lower extremities. MethodsBetween July 2016 and February 2017, 20 patients with severe knee joint osteoarthritis planned to undergo primary TKA were selected as the research object. There were 9 males and 11 females; aged 53-84 years, with an average of 69.4 years. The body mass index was 22.1-31.0 kg/m2, with an average of 24.8 kg/m2. The preoperative range of motion (ROM) of the knee joint was (103.0±19.4)°, the pain visual analogue scale (VAS) score was 5.4±1.3, and the American Hospital of Special Surgery (HSS) score was 58.1±11.3. Before operation, a three-dimensional model of the knee joint was constructed based on the full-length X-ray film of lower extremities and CT of the knee joint. The distal femoral patient-specific cutting guide was designed and fabricated, and the thickness of the distal femoral osteotomy was determined by digital simulation. The thickness of the internal and external condyle of the distal femur osteotomy before operation and the actual thickness of the intraoperative osteotomy were compared. The intraoperative blood loss, postoperative drainage loss, and hidden blood loss were recorded. The ROM of knee joint, VAS score, and HSS score at 3 months after operation were recorded to evaluate effectiveness. The position of the coronal and sagittal plane of the distal femoral prosthesis were assessed by comparing the femoral mechanical-anatomical angle (FMAA), anatomical lateral distal femoral angle (aLDFA), mechanical femoral tibial angle (mFTA), distal femoral flexion angle (DFFA), femoral prosthesis flexion angle (FPFA), anatomical lateral femoral component angle (aLFC), and the angle of the femoral component and femoral shaft (α angle) between pre- and post-operation.ResultsTKA was successfully completed with the aid of the distal femoral patient-specific cutting guide. There was no significant difference between the thickness of the internal and lateral condyle of the distal femur osteotomy before operation and the actual thickness of the intraoperative osteotomy (P>0.05). All patients were followed up 3 months. All incisions healed by first intention, and there was no complications such as periarticular infection and deep vein thrombosis. Except for 1 patient who was not treated with tranexamic acid, the intraoperative blood loss of the rest 19 patients ranged from 30 to 150 mL, with an average of 73.2 mL; the postoperative drainage loss ranged from 20 to 500 mL, with an average of 154.5 mL; and the hidden blood loss ranged from 169.2 to 1 400.0 mL, with an average of 643.8 mL. At 3 months after operation, the ROM of the knee was (111.5±11.5)°, and there was no significant difference when compared with the preoperative one (t=–1.962, P=0.065). The VAS score was 2.4±0.9 and HSS score was 88.2±7.5, showing significant differences when compared with the preoperative ones (t=7.248, P=0.000; t=–11.442, P=0.000). Compared with the preoperative measurements, there was a significant difference in mFTA (P<0.05), and there was no significant difference in aLDFA, FMAA, or DFFA; compared with the preoperative plan, there was no significant difference in FPFA, aLFC, or α angle (P>0.05). ConclusionThe use of distal femoral patient-specific cutting guide based on knee CT and full-length X-ray film of lower extremity can achieve precise osteotomy, improve coronal and sagittal limb alignment, reduce intraoperative blood loss, and obtain satisfactory short-term effectiveness.
ObjectiveTo analyze the CT features of solid pseudopapillary tumor of pancreas (SPTP). MethodsEight patients with SPTP received triple phasic contrast-enhanced CT, and its consistency with pathological findings was analyzed. ResultsSPTP manifested as a solitary and exogenous mass, with a heterogeneous pattern composed of solid and polycystic parts. The shape of SPTP was spherical in four patients, oval in two patients, and shallow lobulation in another two patients. In contrast-enhanced phase images, the solid parts showed mild to moderate enhancement in both arterial and portal phases. Complete capsule was showed in seven patients, and nodules were found in the wall of mass in five patients. Hemorrhage was seen in two patients and calcification was showed in five patients. The dilation of pancreatic duct was found in one patient, liver metastases was showed in one patient, and the invasion of tumor to posterior gastric wall was found in one patient. Pseudopapillary structure, hemorrhage, necrosis, and cystic degeneration were showed in all patients by histological study. ConclusionSPTP has certain characteristic CT imaging manifestations consistent with histological features, which is helpful for the diagnosis and differential diagnosis of SPTP.