The relationship between fractional anisotropy value and tumor microarchitecture in late-stage rat glioma

Objective To explore the magnetic resonance diffusion tensor imaging (MR-DTI) features of in the late stage of Wistar rat C6 brain glioma, and the relationship between fractional anisotropy value and tumor microarchitecture. Methods The concentration of more than 1.0 × 10

Clinical analysis of 939 patients with adrenal lesions detected by abdominal computed tomography / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the prevalence, etiology and clinical characteristics of adrenal lesions detected by abdominal computed tomography (CT).</p><p><b>METHODS</b>This retrospective study was conducted in patients with adrenal lesions detected by abdominal CT examinations in Nanfang Hospital between July, 2014 and June, 2015. The clinical data of the patients were collected for analysis of the demographics, comorbidities, imaging characteristics, biochemical profiles, clinical diagnosis and intervention.</p><p><b>RESULTS</b>A total of 939 patients with adrenal lesions were identified from 19 004 patients undergoing abdominal CT scan over the defined period. The mean age of the patients was 53.2 years and 560 of the patients were male. Among the total cases with adrenal lesions, the percentages of cases with adrenal masses tended to increase progressively with age. Endocrine studies were done in 270 of the total patients, which identified non-functioning masses in 38.9%, primary aldosteronism in 16.3%, Cushing's syndrome in 4.1%, subclinical Cushing's syndrome in 7.0%, and pheochromocytomas in 7.0% of the cases. Adrenal incidentalomas was detected in 191 patients, with a detection rate of 1.0% among the overall patients undergoing abdominal CT scans. Imaging study detected adenomas (70.3%), cortical carcinomas (2.4%), and metastases (0.5%). Of 191 patients with adrenal incidentalomas, only 76 (39.8%) underwent endocrine evaluation, including 34 with nonfunctioning adrenal masses, 17 with pheochromocytoma, 7 with primary aldosteronism, and 5 with subclinical Cushing's syndrome.</p><p><b>CONCLUSION</b>s The overall detection rates of adrenal lesions and adrenal incidentalomas by abdominal CT were 4.9% and 1.0%, respectively, in our cohort of patients undergoing the examination over the defined period. Although most of the lesions were benign and nonfunctioning, malignant and functional lesions were also detected. As many as 60% of the patients with adrenal incidentalomas did not have hormonal testing. Clinicians need to have greater awareness of adrenal incidentalomas and standard protocol for its management should be established.</p>

Value of PI-RADS v2 scores combined with prostate specific antigen in diagnosis of peripheral zone prostate cancer: a logistic regression analysis / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the value of Prostate Imaging and Reporting and Data System: Version 2 (PI-RADS v2) combined with prostate specific antigen (PSA) in the diagnosis of peripheral zone (PZ) prostate cancer (PCa).</p><p><b>METHODS</b>The preoperative magnetic resonance imaging and PSA data were ananlyzed for 69 patients with pathologically confirmed PCa and 109 non-PCa patients. PI-RADS v2 scores (1-5) was used to evaluate the risk of PZ PCa. The total PSA (tPSA) level, free to total PSA ratio (f/t PSA), PSA density (PSAD), PZ-PSAD and PI-RADS v2 scores were compared between the PCa and non-PCa patients. Logistic regression models were established with parameters that differed significantly the two groups. The receiver opearting characteristics (ROC) curve was constructed based on the P values derived from the logical regression models and PI-RADS scores to assess the diagnostic efficiency.</p><p><b>RESULTS</b>PI-RADS v2 score, tPSA, f/t PSA, PSAD and PZ-PSAD differed significantly between the two groups (P<0.01). Four predictive multivariate models were established: Logit P=-6.825+1.024PI-RADS v2+ 0.223tPSA (A), Logit P=-4.354+1.586PI-RADS v2-12.7841f/tPSA (B), Logit P=-8.993+1.630PI-RADS v2+17.091PSAD (C), and Logit P=-9.434+1.596PI-RADS v2+10.494PZ-PSAD (D), whose area under the ROC curves was 0.908, 0.891, 0.944, and 0.961, respectively, all significantly greater than that of PI-RADS v2 score (P<0.05).</p><p><b>CONCLUSION</b>Compared with PI-RADS v2 score alone, the combination of PI-RADS v2 score and PSA in the logistic regression model can improve the diagnostic efficiency of PZ PCa and offers better confidence in the decision of biopsy in suspected cases.</p>

The relationship between fractional anisotropy value and tumor microarchitecture in late-stage rat glioma

OBJECTIVE@#To explore the magnetic resonance diffusion tensor imaging (MR-DTI) features of in the late stage of Wistar rat C6 brain glioma, and the relationship between fractional anisotropy value and tumor microarchitecture.@*METHODS@#The concentration of more than 1.0 × 10/10 μL glioma cells and complete medium were injected stereotactically into the right caudate nucleus of the experimental group (n = 35) and control group (n = 10), respectively. Conventional MRI, DTI, and enhanced T1WI scans were Performed using the GE Signa HD × 3.0T MRI scanner about 3-4 weeks after implantation for the rats. Postprocessing was done using the DTI specific software Function Tool to gain FA image. Many ROIs were drawn avoiding hemorrhage, necrosis areas in tumor parenchyma, the value of FA was recorded. Each surviving rat brain was examined histologically using HE and immunohistochemical staining for VEGF and CD34. Pearson correlation analysis was used to determine the relationships between FA values and VEGF, MVD, cell density, respectively.@*RESULTS@#A total of 35 tumor-bearing rats were confirmed the tumor formation by the subsequent MRI and pathological examination. The mean FA values of the tumor and the contralateral brain tissue were 0.17 ± 0.03 and 0.31 ± 0.05 respectively, and the difference was statistically significant (t = 12.80, P  0.05). FA value in the late stage of Wistar rat C6 brain glioma has significant positive correlation to VEGF, MVD, cell density. The correlation coefficients between FA and VEGF, MVD, and cell density were 0.67, 0.65 and 0.71 (P < 0.05), respectively.@*CONCLUSIONS@#The FA value of rat glioma tumor in the late stage can preoperatively provide an accurate, reliable and noninvasive imaging monitoring method to evaluate the microstructure of glioma (cell density, the extent of angiogenesis, fiber bundle integrity and tumor cell infiltration and so on), predict the biological behavior of the tumor and make out surgical plan.

¹¹C-methionine and ¹⁸F-fluorodeoxyglucose positron emission tomography/CT in the evaluation of patients with suspected primary and residual/recurrent gliomas / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>(18)F-fluorodeoxyglucose (FDG) is the most widely used radiotracer in tumor imaging, but its use for brain gliomas and recurrence is limited by the high (18)F-FDG uptake in normal brain tissue. (11)C-methionine (MET) has low uptake in the normal brain tissue, providing potential advantages over (18)F-FDG. The aim of the study was to investigate the diagnostic value of (11)C-MET compared to (18)F-FDG positron emission tomography and computed tomography (PET/CT) in patients with suspected primary and residual/recurrent gliomas.</p><p><b>METHODS</b>Eighty paired PET/CT scans using (11)C-MET and (18)F-FDG were performed on 44 newly diagnosed patients with suspected gliomas and 36 post-operative patients with suspected residual/recurrent tumors. PET/CT results were evaluated by visual and semiquantitative analysis. The sensitivity, specificity and accuracy for detection of gliomas and residual/recurrent tumors were calculated using visual analysis. Tumor to contralateral normal gray matter (T/G) ratio was calculated for semiquantitative analysis.</p><p><b>RESULTS</b>Final pathology of the 44 newly diagnosed patients included 26 gliomas (14 high-grade and 12 low-grade tumors) and 18 non-glioma benign lesions. Residual/recurrent gliomas were verified in 28 patients and excluded in 8/36 post-operative patients by subsequent histopathologic examination and/or clinical follow-up for more than six months. The sensitivity, specificity and accuracy of (11)C-MET PET/CT were 88.5%, 83.3% and 86.4% for gliomas and 96.4%, 87.5% and 94.4% for residual/recurrent gliomas, respectively. The sensitivity, specificity and accuracy of (18)F-FDG PET/CT were 50.0%, 88.9% and 65.9% for gliomas and 46.4%, 100.0% and 58.3% for residual/recurrent gliomas, respectively. (11)C-MET had a higher sensitivity than (18)F-FDG (83.3% vs. 33.3%, P = 0.031) in low-grade gliomas, but had no significant difference in sensitivity from (18)F-FDG for high-grade gliomas (92.9% vs. 64.3%, P = 0.219). (11)C-MET T/G uptake ratios in high-grade gliomas, low-grade gliomas and benign lesions were 1.94 ± 0.53, 1.78 ± 0.61 and 1.06 ± 0.34, respectively. (18)F-FDG T/G uptake ratios in high-grade gliomas, low-grade gliomas and benign lesions were 1.05 ± 0.37, 0.66 ± 0.14 and 0.63 ± 0.17, respectively.</p><p><b>CONCLUSIONS</b>(11)C-MET PET/CT is superior to (18)F-FDG PET/CT in detecting and delineating gliomas and residual/recurrent tumors, especially low-grade gliomas and residual/recurrent lesions present in gray matter, but its role in non-invasive grading of the tumors is limited.</p>

Comparison between 11 C-methionine and 18F-FDG PET/CT in diagnosing residual or recurrent glioma / 中华核医学杂志

Objective To assess the value of 11 C-methionine (MET) PET/CT for the diagnosis of residual or recurrent glioma in comparison to 18 F-FDG PET/CT. Methods Forty-six patients suspected of residual or recurrent glioma underwent both 11 C-MET and 18 F-FDG PET/CT within 5-day interval. The glioma was considered as positive on PET/CT images based on ( 1 ) visual judgment of higher tracer uptake compared with the normal gray matter; (2) semiquantitative analysis of tumor to contralateral normal gray matter (T/G) and contralateral normal white matter (T/W) ratios. The diagnosis was confirmed by stereotsctic biopsy or radiological findings of MRI or CT and clinical follow-up ( ＞6 months). The Chi-square test and paired t test were used for statistical analysis. Results Residual or recurrent glioma was confirmed in 36 patients. The sensitivity, specificity, accuracy of 11C-MET and 18F-FDG PET/CT were 94.4% (34/36) vs 47.2% (17/36), 90.0% (9/10) vs 100% (10/10), 93.5% (43/46) va 58.7% (27/46) (x2 =19. 429, 1. 053, 15. 294, P ＜0.001, ＞0.05, ＜0.001 ), respectively. The T/G and T/W ratios of residual/recurrent giloma by 11 C-MET were significantly higher than those by 18 F-FDG (T/G ratio: 1.68 ± 0.23 vs 1.13 ±0.51, t = 5. 877, P ＜ 0. 001; T/W ratio: 2.52 ± 0.28 vs 1.42 ± 0. 57, t = 10. 470, P ＜0. 001 ). Conclusion 11 C-MET PET/CT is more sensitive and accurate than 18 F-FDG PET/CT for the detection of residual or recurrent glioma.

Synthesis of Gal-BSA-SPIO and magnetic resonance imaging of ASG receptors in rabbits bearing liver VX2 tumor and human liver / 南方医科大学学报

<p><b>OBJECTIVE</b>To synthesize Gal-BSA-SPIO as the magnetic resonance imaging (MRI) contrast agent targeting asialoglycoprotein (ASG) receptors in the liver and observe its role in MRI detection of hepatocellular carcinomas (HCCs).</p><p><b>METHODS</b>Gal-BSA was synthesized by means of reductive amination and mixed with SPIO in ice bath to prepare Gal-BSA-SPIO complex. Twenty rabbits bearing VX2 liver tumor underwent MRI enhanced by SPIO (n=10) and Gal-BSA-SPIO (n=10), and the T2 values of the liver and tumor before and after the contrast imaging were measured. Fresh human normal hepatic tissues (n=3), cirrhotic tissues (n=4) and HCC tissues (n=6) were obtained and incubated with Gal-BSA-SPIO followed by Perl's Prussian blue staining to observe the distribution of ASG receptors.</p><p><b>RESULTS</b>The size of the Gal-BSA-SPIO particles was 34.4 nm. The 20 rabbits bearing VX2 tumor, with tumor size ranging from 3 mm to 12 mm, showed isointense signal in the liver and hypointense signal in the tumor on T1WI, and isointense signal in the liver and slightly hyperintense signal in the tumor on GRE T2*WI. The signal intensity of the liver decreased slightly or moderately after administration of SPIO in the rabbits, and administration Gal-BSA-SPIO resulted in obvious reduction in the signal intensity of the liver. The signal intensities of the tumors did not exhibit obvious changes after the administration of SPIO or Gal-BSA-SPIO. Histological examination revealed numerous blue iron deposits in the Kupffer cells in SPIO group and in the hepatocytes in Gal-BSA-SPIO group, but not in the tumors in either of the groups. The human liver specimens incubated with Gal-BSA-SPIO contained numerous blue iron deposits in the hepatocyte cytoplasm and cell membrane in normal liver tissue, but the deposits were reduced in the cirrhotic tissue and almost absent in the HCC tissue.</p><p><b>CONCLUSION</b>Gal-BSA-SPIO can specifically bind to ASG receptors on hepatocyte membrane to improve the tumor-liver contrast-to-noise ratio.</p>

Magnetic resonance imaging diagnosis of grades I and II ganglioglioma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the magnetic resonance imaging (MRI) findings and clinical features of grades I and II gangliogliomas and improve their diagnostic accuracy.</p><p><b>METHODS</b>Fourteen patients with grade I or II ganglioglioma underwent plain MRI and contrast-enhanced T1-weighted imaging (T1WI).</p><p><b>RESULTS</b>Eleven supratentorial and 3 infratentorial gangliogliomas were identified in these patients including 13 patients below 30 years and 11 with epilepsy. All the 14 patients showed hypointense tumors on T1WI and hyperintense lesions on T2WI, and 4 showed solitary cystic foci (including 2 patients with grade I and 2 with grade II gangliogliomas). Contrasted T1WI revealed no enhancement in 5 patients (4 with grade I and 1 with grade II gangliogliomas), diffuse mild enhancement in the foci in 3 patients with grade II gangliogliomas, gyrus-like enhancement in 4 patients (2 with grade I and 2 with grade II gangliogliomas), and intense enhancement in the nodules on the capsule wall in 2 grade II patients.</p><p><b>CONCLUSION</b>Grades I and II gangliogliomas may present with characteristic MRI findings, which may help improve the diagnostic accuracy of gangliogliomas in combination with patients' clinical data and onset age.</p>

Magnetic resonance imaging findings of capillary hemangioma in the brain / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the magnetic resonance imaging (MRI) findings of capillary hemangioma in the brain to improve the diagnosis of capillary hemangioma.</p><p><b>METHODS</b>The MRI findings were analyzed in 6 patients with pathologically confirmed capillary hemangioma in the brain to define the characteristic MRI features of capillary hemangioma.</p><p><b>RESULTS</b>In the 6 patients, the capillary hemangiomas were located in the pons (n=1), bulbus medullae (n=1), bilateral cerebellar hemisphere (n=1), right temporal lobe (n=1) or left frontal lobe (n=1). Three patients had subacute hemorrhage, 2 had cystic degeneration and 1 had solid tumors, all shoeing heterogeneous MRI signals. Contrast-enhanced MR scans revealed marked heterogeneous enhancement with clear boundaries of the tumor parenchyma, where spots and thin strips without enhancement were seen in 5 cases; vascular network was seen in 1 case. Drainage vessels connected to the lesions were found in 3 cases.</p><p><b>CONCLUSION</b>MRI has a high diagnostic value for intracranial capillary hemangioma.</p>

Mammography and magnetic resonance imaging for diagnosis of the intraductal papilloma of the breast / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the features of intraductal papilloma of the breast in mammography and magnetic resonance imaging (MRI) and assess the diagnostic values of the two imaging modalities.</p><p><b>METHODS</b>Fifteen patients with intraductal papilloma of the breast confirmed surgically and pathologically underwent X-ray examination of the breast, and 11 of them also received enhanced MRI. The imaging findings by mammography and MRI were compared.</p><p><b>RESULTS</b>Enhanced MRI clearly displayed the location and morphology of the intraductal papilloma, and 7 patients showed smooth tumor margins and 2 showed irregular margins. On T(1)WI, the lesions were isointense or slightly hypointense, and appeared isointense or slightly hyperintense on T(2)WI. Some of the intraductal papillomas were seen encapsulated in the dilated ductal. The varying enhancement features of the lesions increased the difficulty in distinguishing from carcinoma. Mammography identified intraductal papillomas only in 2 of the 15 cases (13%) with lesion feature similar to that found by MRI. Fine cluster calcification was found in 1 case.</p><p><b>CONCLUSION</b>MRI can more accurately define the location of the lesion than X-ray. In spite of some resemblance in the MRI findings between intraductal papillomas and breast carcinoma, MRI still serves as a useful diagnostic modality for intraductal papilloma that shows some characteristic findings.</p>

Imaging diagnosis of small hepatocellular carcinoma using ultrasound, contrast-enhanced ultrasound and multislice spiral CT / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the value of gray-scale ultrasound, contrast-enhanced ultrasound and multislice spiral CT in early and differential imaging diagnosis of small hepatocellular carcinoma (SHCC).</p><p><b>METHODS</b>This study included 35 patients with space-occupying lesions in the liver identified by routine ultrasound examination. The hemodynamics of the patients was recorded during the arterial, portal and lag phases using contrast-enhanced ultrasound. The enhancement features of the 3 phases were observed using multislice spiral CT. All the cases were confirmed by pathological examinations.</p><p><b>RESULTS</b>For SHCC diagnosis, gray-scale ultrasound, contrast-enhanced ultrasound and multislice spiral CT showed a sensitivity of 77.8%, 94.4%, and 100%, specificity of 88.2%, 100%, and 94.1%, positive predictive value of 87.5%, 100%, and 94.7%, negative predictive values 78.9%, 94.4%, and 100%, concordance rate of 82.9%, 97.1%, and 97.1% and Younden index of 0.66, 0.94, and 0.94, respectively.</p><p><b>CONCLUSIONS</b>Contrast-enhanced ultrasound and multislice spiral CT have significantly greater diagnostic efficacy than gray-scale ultrasound in early and differential diagnosis of SHCC. But in some atypical cases, gray-scale ultrasound, contrast-enhanced ultrasound and multislice CT have to be combined to establish a diagnosis.</p>

Establishment of a rabbit model bearing transplanted endometrial carcinoma and magnetic resonance imaging features of the metastatic lymph nodes / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a rabbit model bearing endometrial carcinoma and observe the magnetic resonance imaging (MRI) features of the metastatic lymph nodes.</p><p><b>METHODS</b>VX(2) tumor grafts were orthotopically embedded into the endometrium of the rabbits. Three weeks after the implantation, the tumor and the metastatic retroperitoneal lymph nodes were examined with MRI, and the signal intensities and the size of the lymph nodes were compared with those in normal rabbits.</p><p><b>RESULTS</b>Orthotopic tumor growth was observed in all the rabbits. Tumor infiltration of the serosa and retroperitoneal lymph node metastasis occurred 3 weeks after tumor implantation. MRI demonstrated obviously lymph node enlargement in the tumor-bearing rabbits as compared with those of normal rabbits, while the signal intensity of the lymph nodes were comparable between them.</p><p><b>CONCLUSION</b>The endometrial carcinoma in this rabbit model well simulate the metastatic behavior of human endometrial carcinoma, and may serve as a good model for testing the efficacy of the contrast agents for MRI of the lymph nodes.</p>

Magnetic resonance cholangiopancreatography of pancreaticobiliary duct dilation due to pancreatic carcinoma and chronic pancreatitis / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the findings of pancreaticobiliary duct dilation due to pancreatic carcinoma and chronic pancreatitis by magnetic resonance cholangiopancreatography (MRCP).</p><p><b>METHODS</b>MRCP findings in 28 cases of pancreatic carcinoma and 42 cases of chronic pancreatitis were retrospectively analyzed. Both plain MR and MRCP examinations were performed in all the cases after oral Gd-DTPA dilution.</p><p><b>RESULTS</b>MRCP in the patients with pancreatic carcinoma displayed dilated pancreatic duct with smooth and regular caliber (n=16, 72.7%), dilated common biliary duct with abrupt rupture in most cases (n=18, 90%) and intra- and extra-hepatic cholangiectasis (n=12, 42.8%), and the double-duct sign (n=19, 86.5%). In the patients with chronic pancreatitis, MRCP identified irregular dilation of the pancreatic duct across the whole segment of the lesion (n= 20, 60.6%), taper of the dilated common bile duct (n=8, 80%), stones within the pancreatic duct (n=5, 11.9%), and pancreatic pseudocsyt within the pancreatic duct (n=21, 50%).</p><p><b>CONCLUSION</b>Cholangiopancreatographic findings of pancreaticobiliary duct dilation are of great value in distinguishing pancreatic carcinoma from chronic pancreatitis.</p>

A comparative study of Gd-DTPA and HSA-Gd-DTPA in magnetic resonance lymphography / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the effects of two contrast agents, Gd-DTPA and HSA-Gd-DTPA, in magnetic resonance (MR) lymphography.</p><p><b>METHODS</b>Twelve New-Zealand rabbits were randomized into Gd-DTPA and HSA-Gd-DTPA groups with subcutaneous (interdigital skin fold) injection of the two contrast agents (0.2 ml of 0.5 mmol/L Gd(3+)) for MR lymphography of the popliteal lymph nodes examined in the axial and sagital orientation. T(1)-weighted, T1-weighted fat suppressed, and T(2)-weighted spin-echo (SE) images of the lymph nodes were obtained in plain scans. The post-contrast scanning started at 30 min, 1 h and 3 h after Gd-DTPA administration and at 10 min, 30 min and 60 min after HSA-Gd-DTPA injection to obtain T(1)-weighted images with identical imaging parameters. The signal intensity of popliteal lymph node was measured and the enhancement rate calculated.</p><p><b>RESULTS</b>After subcutaneous injection, Gd-DTPA quickly entered blood circulation to result in obvious enhancement of the anterior-tibial vein and the urine and also in heterogeneous enhancement of the popliteal lymph nodes. HSA-Gd-DTPA did not enter the blood, causing obvious homogeneous enhancement of the lymphatic vessels and lymph nodes. HSA-Gd-DTPA resulted in higher enhancement rate than Gd-DTPA, and the enhancement rate in Gd-DTPA group decreased with time as opposed to that of the HSA-Gd-DTPA group.</p><p><b>CONCLUSION</b>HSA-Gd-DTPA has better performance than Gd-DTPA in MR lymphography after subcutaneous administration.</p>

CT diagnosis and pathological findings of testicular lesion / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the value of CT scan in the diagnosis and differential diagnosis of testicular space-occupying lesions.</p><p><b>METHODS</b>In patients with testicular space-occupying lesions, 11 underwent examinations for such tumor markers as alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG). Plain CT scans were performed with a section thickness and interval of 2 mm followed by enhanced scans after intravenous bolus injection of 70 ml 60% ultravist. Spiral CT multiplanar reconstruction images were also obtained.</p><p><b>RESULTS</b>Of the 13 patients, histopathologically confirmed seminoma was found in 3, endodermal sinus tumor in 1, teratoma in 2, mixed germinoma in 2, leucoma in 1 case, abscess in 2, and tuberculosis in 2. One seminoma patient had slightly elevated AFP level while 5 of the 6 noneminoma patients (83%) had elevated AFP level. CT scans displayed characteristic features for diagnosis of testicular space-occupying lesions. Spiral CT with multiplanar reconstruction allowed full view of the lesions and demonstrated their relationship with the surrounding structures.</p><p><b>CONCLUSION</b>CT scan in combination with the clinical analysis and tumor marker examinations can be of important value in the diagnosis and differential diagnosis of testicular space-occupying lesions. The application of spiral CT multiplanar reconstruction also helps in the diagnosis.</p>

Magnetic resonance imaging findings of liver injury induced by three-dimensional conformal radiotherapy / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the magnetic resonance imaging (MRI) findings of radiation-induced liver injury following three-dimensional conformal radiotherapy.</p><p><b>METHODS</b>A retrospective review of the MRI data was conducted in 20 patients treated between September 2000 and October 2005, who suffered liver injuries induced by 1 or 2 three-dimensional conformal radiotherapy sessions for liver neoplasm. The patients underwent MR scans with T2-weighted sequences and T1-weighted sequences in both plain and Gd-DTPA enhanced MRI. Four patients with suspected tumor relapse suggested by MRI were pathologically confirmed to have radiation-induced liver injury.</p><p><b>RESULTS</b>Acute radiation-induced liver injury was represented by large patches of liver edema consistent with the irradiation volume, showing low signal intensity on T1-weighted images (T1WI) and high signal intensity on T2-weighted images (T2WI) without arterial phase enhancement after Gd-DTPA injection. Delayed radiation-induced liver injury was manifested by slightly low-intensity signal on plain T1WI and slightly high-intensity signal on T2WI without obvious arterial phase enhancement following Gd-DTPA injection but with marked enhancement during the portal-venous and delayed phases.</p><p><b>CONCLUSION</b>Radiation-induced liver injury presents characteristic MRI features, and plain and dynamic enhanced MRI can be of great value for its diagnosis.</p>

CT perfusion study of acute local cerebral infarction in rhesus monkeys / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the value of CT perfusion in early diagnosis and management of superacute local cerebral infarction in rhesus monkeys.</p><p><b>METHOD</b>Acute local cerebral infarction was induced in the rhesus monkeys during digital subtraction angiography (DSA) by introduction of pale thrombus prepared from autologous blood into the M1 branch of the middle cerebral artery (MCA). Plain CT scan and CT perfusion scanning were performed at different time points before and after DSA operation, and the results were analyzed in conjunction with the pathologic changes.</p><p><b>RESULTS</b>Ischemic lesions were displayed on CT perfusion images, which showed local hypoperfusion, reduced cerebral blood flow and volume, and mean transit time delay in the compromised area. Local hypointense infarct area was identified in plain CT scan 24 h after the DSA operation, and the results were in good agreement with pathological examination during autopsy.</p><p><b>CONCLUSION</b>CT perfusion imaging of the brain can accurately capture the cerebral perfusion deficits in acute ischemic stroke before morphologic changes take place, and therefore provides good means for thrombolytic treatment evaluation of stroke.</p>

Targeted magnetic resonance imaging with intraperitoneal and intravenous streptavidin (SA)-DTPA-Gd: a comparative study in tumor-bearing nude mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of streptavidin (SA)-DTPA-Gd after intraperitoneal and intravenous administration for tumor enhancement in targeted magnetic resonance imaging (MRI).</p><p><b>METHODS</b>Biotinylated monoclonal antibody CL3 (600 microg) was intravenously injected into 12 BALB/c nude mice with subcutaneous inoculation of LoVo cells, followed by administration of 80 microg avidin as the chaser 24 h later and then SA-DTPA-Gd was injected intravenously or intraperitoneally after another 30 min. MRI was performed before and 20, 60 min and 3, 6, 9, 12 h after the injection of the contrast agents, and the MR signal intensity of the tumor and liver was determined.</p><p><b>RESULT</b>The maximum enhancement ratio of the tumor was 70.2% in the intravenous injection group and 46.4% in the intraperitoneal group, showing significant difference between them. The maximal enhancement rate of the liver was 23.7% in the intraperitoneal group and 20.4% in the intravenous group, showing no significant difference.</p><p><b>CONCLUSION</b>MR targeted imaging with biotinylated monoclonal antibody CL3 and SA-DTPA-Gd has specific enhancement effect. Higher blood level of SA-DTPA-Gd in the intravenous group facilitates the tumor enhancement in MRI in subcutaneous tumor model.</p>

Helical CT presentation of focal nodular hyperplasia of the liver / 南方医科大学学报

<p><b>OBJECTIVE</b>To improve the diagnostic accuracy of focal nodular hyperplasia (FNH) of the liver by analyzing its findings by helical CT multiphase scanning.</p><p><b>METHODS</b>A retrospective analysis of the plain scanning and dynamic enhanced scanning helical CT findings was conducted in 20 pathologically verified FNH cases.</p><p><b>RESULTS</b>On plain CT scans, the FNH lesions appeared as heterogeneous or homogeneous hypodense areas. In the arterial phase, all lesions were vigorously and homogeneously enhanced except for the central scar and lesions in 1 case. In 6 cases, tortuous and dilated arteries were seen in the center or peripheral of the lesion in 16-slice spiral CT. In the portal venous phase and delayed phase, the lesions were slightly hyperdense, isodense or slightly hypodense. Central scar was found in 13 cases, which showed late enhancement. Atypical findings included multinodular FNH in 2 cases, pseudocapsular enhancement in 2 cases, calcification in 1 case, and necrosis in 1 case.</p><p><b>CONCLUSION</b>Multiphase helical CT scanning can fully display the pathological and blood supply characteristics of FNH and improve the differentiation of FNH from other malignant hypervascular tumors.</p>

Magnetic resonance imaging for diagnosis of mid- and long-term complication after liver transplantation / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the value of magnetic resonance imaging (MRI) in mid- and long-term complication monitoring after liver transplantation.</p><p><b>METHODS</b>Twenty-one recipients receiving orthotropic liver transplantation between Feb 2003 and May 2005 were enrolled in this study. FLASH T(1)-weighted, T(2)-weighted fast spin echo, T(2)-weighted fat suppression, dynamic gadolinium-enhanced, MR cholangiopancreatography (MRCP) and three-dimensional dynamic gadolinium-enhanced FISP MRA images were obtained.</p><p><b>RESULTS</b>Of the 21 patients, bile duct complications were detected in all cases and liver arterial and venous complications in 8 cases. Liver cancer relapse occurred in 5 cases and allograft failure in 4.</p><p><b>CONCLUSION</b>MR imaging allows effective monitoring of mid- and long-term complications of liver transplantation, which provides valuable clues for their clinical treatment.</p>