[Pathological correlation of dynamic magnetic resonance findings for chromophobe cell renal carcinoma].

OBJECTIVE: To explore the dynamic magnetic resonance (MR) imaging findings of chromophobe cell renal carcinoma and evaluate its pathological correlation. METHODS: Twelve cases with chromophobe cell renal carcinoma confirmed by surgical pathology underwent MR plain scanning and dynamic enhancement scanning before operation. And the MR data were reviewed and analyzed retrospectively in comparison with surgical and pathological results. RESULTS: Twelve lesions were located in right kidney (n = 9) and left kidney (n = 3) with a mean tumor diameter of 7.3 cm (range: 3.2 - 12.6 cm). They were located in renal cortex (n = 1), renal medulla (n = 9) and the middle of cortex and medulla with a relatively normal renal shape. Nine lesions appeared global and 3 elliptic in shape. Well-defined margin was showed in 12 lesions and a thin capsule was observed in all lesions. The tumor presented a low to middle homogeneous signal intensity on T1WI and intermediates homogeneous signal intensity on fat saturated FSE-T2WI with a hypointense thin capsule and a hyperintense central scar. A mild-to-middle degree of tumor enhancement in cortical phase (tumor SI change 120.3% with a standard deviation of 84.3 and a median of 115.2%) was slightly lower, isointense or slightly higher than renal medulla. And obvious enhancement in portal venous phase(tumor SI change 173.7% with a standard deviation of 92.4 and a median of 171.5%) was lower than renal medulla. CONCLUSION: Chromophobe cell renal carcinoma typically forms large and well-circumscribed global solid masses in renal medulla. With a relatively normal renal shape and a thin capsule, it shows intermediate homogeneous signal intensity on T1WI and T2WI. And a middle degree enhancement with central stellate scar is found in some patients.

Preliminary study on MR colonography with air enema in detection of colorectal neoplasms.

BACKGROUND: The few studies on MR colonography with air enema involved feasibility of bowel distention and imaging quality and lacked detection sensitivity of colorectal neoplasms. The purpose of this prospective study was to assess the detection sensitivity of colorectal neoplasms with the three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography with air enema. METHODS: A total of 30 patients scheduled for optical colonoscopy due to rectal bleeding, positive fecal occult blood test results or altered bowel habits were recruited and successfully underwent entire colorectal examinations with three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography and subsequent optical colonoscopy on the same day. Detection sensitivity of colorectal neoplasms with MR colonography was statistically analyzed on a per-neoplasm size basis by using findings from optical colonoscopy and histopathological examinations as the reference standards. RESULTS: Seventy-six neoplasms were detected with optical colonoscopy, consisting of 1 mm-5 mm (n = 11), 6 mm-9 mm (n = 29) and ≥ 10 mm (n = 36) in diameter. Detection sensitivities of 1 mm-5 mm, 6 mm-9 mm, ≥ 10 mm and ≥ 6 mm colorectal neoplasms with MR colonography were 9.1%, 75.9%, 100% and 89.2%, respectively; overall detection sensitivity for all sizes colorectal neoplasms was 77.6%. CONCLUSIONS: Detection sensitivity of three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography with air enema is low for 1 mm-5 mm colorectal neoplasms, but the detection sensitivity is 89.2% for ≥ 6 mm neoplasms, and all ≥ 10 mm neoplasms could be detected.

[CT and MRI imaging features of peripheral primitive neuroectodermal tumors].

OBJECTIVE: To investigate the CT and MRI features of peripheral primitive neuroectodermal tumors (pPNETs) and evaluate its diagnostic value. METHODS: The clinicopathological data of 9 surgically treated patients with peripheral primitive neuroectodermal tumors confirmed by pathology were collected, spiral CT (4/9) and MRI (6/9) plain scanning and dynamic enhancement scanning were performed preoperatively. Both CT and MRI scannings were performed in 1 case. Those CT and MR images were retrospectively reviewed and analyzed together with clinicopathological findings. RESULTS: The 9 lesions were located in skeletal muscles (n = 6), pelvic cavity (n = 2) and thoracic cavity (n = 1). The tumor size was 7.4-18.3 cm in diameter with a mean diameter of 11.6 cm. The shape of those lesions was round or ellipse (4 lesions) and irregular (5 lesions). The tumor usually presented as ill-defined masses, with homogeneous (n = 2) or inhomogeneous density (n = 7). Seven cases, including the 3 lesions located in the chest and pelvis, showed obvious necrosis and multilocular cyst formation. The tumors showed iso-density as that of the adjacent muscles on CT plain scans and moderate heterogeneous enhancement after intravenous injection of contrast agents. The features of the tumors on the MRI including slightly low signal intensity on SE T1-weighted imaging, iso-signal intensity or slightly high signal intensity on FSE T2-weighted imaging and heterogeneous dynamic delayed contrast-enhancement with obvious necrosis in most of them. Six cases had a lesion in the skeletal muscles, presented as a giant ill-defined masse surrounding bone and extended along neural route with bone destruction to varying degrees. CONCLUSION: Primitive neuroectodermal tumor is a kind of malignant tumor with proliferation of small, undifferentiated neuroectodermal cells, usually occurring in children or adolescent and frequently located in the extremities, chest cavity, pelvic cavity and chest wall. It typically presents as a large, ill-defined masse extending along neural route with heterogeneous and obvious enhancement after intravenous injection of contrast agents. The tumors located in the chest and pelvic cavities and some in the extremities show obvious necrosis and multilocular cyst formation, while some of the tumors in the extremities appear as homogeneous solid masses.

[Evaluation of CT diagnostic criteria for peri-pancreatic artery and vein invasion in pancreatic carcinoma].

UNLABELLED: OBJECTIVE; To evaluate the clinical value of different CT diagnostic criteria for peripancreatic artery and vein invasion in pancreatic carcinoma through comparison with the findings on surgical exploration. METHODS: Of 72 patients of having suspected pancreatic carcinoma were examined by multiplane spiral CT. Among 43 confirmed by surgical pathology; 15 underwent pancreaticoduodenectomy; 28 were found to have unresectable tumors. The peri-pancreatic major vessels including the superior mesenteric artery, celiac artery, hepatic artery, superior mesenteric vein and portal vein were explored carefully during surgical exploration. RESULTS: The criteria for peri-pancreatic artery invasion was the presence of one of the following signs: artery embeded in tumor, or more than half of the artery circumference involved by tumor with wall irregularity or stenosis. The sensitivity of the above described criteria was 75.0% (12/16). If the criteria of tumor involvement exceeding half of the vessel circumference were adhered to, the sensitivity was 87.5% (14/16), which was high than the former, but the specificity was lower than that of the former one (90.2% versus 95.1%). The criteria for peri-pancreatic vein invasion was presence of any of the following signs: vein obliteration, more than half of the vein circumference involved by tumor, vein wall irregularity, vein stenosis, tear-drop sign of superior mesenteric artery. The sensitivity of the above described criteria was 92.9% (39/42), higher than that of the criteria that more than half of the vessel circumference was involved by the tumor (69.0%, 29/42), but the specificity of both criteria was the same (97.4%, 37/38). CONCLUSION: For assessing peri-pancreatic artery and vein invasion, using the combination of different CT diagnostic criteria has higher accuracy than when using only criteria of more than half of vessel circumference involved by tumor.

Assessment of hemodynamics in precancerous lesion of hepatocellular carcinoma: evaluation with MR perfusion.

AIM: To investigate the hemodynamic changes in a precancerous lesion model of hepatocellular carcinoma (HCC). METHODS: Hemodynamic changes in 18 Wistar rats were studied with non-invasive magnetic resonance (MR) perfusion. The changes induced by diethylnitrosamine (DEN) developed into liver nodular lesions due to hepatic cirrhosis during the progression of carcinogenesis. The MR perfusion data [positive enhancement integral (PEI)] were compared between the nodular lesions corresponding well with MR images and pathology and their surrounding hepatic parenchyma. RESULTS: A total of 46 nodules were located by MR imaging and autopsy, including 22 dysplastic nodules (DN), 9 regenerative nodules (RN), 10 early HCCs and 5 overt HCCs. Among the 22 DNs, 6 were low-grade DN (LGDN) and 16 were high-grade DN (HGDN). The average PEI of RN, DN, early and overt HCC was 205.67 +/- 31.17, 161.94 +/- 20.74, 226.09 +/- 34.83, 491.86 +/- 44.61 respectively, and their liver parenchyma nearby was 204.84 +/- 70.19. Comparison of the blood perfusion index between each RN and its surrounding hepatic parenchyma showed no statistically significant difference (P = 0.06). There were significant differences in DN (P = 0.02). During the late hepatic arterial phase, the perfusion curve in DN declined. DN had an iso-signal intensity at the early hepatic arterial phase and a low signal intensity at the portal venous phase. Of the 10 early HCCs, 4 demonstrated less blood perfusion and 6 displayed minimally increased blood flow compared to the surrounding parenchyma. Five HCCs showed significantly increased blood supply compared to the surrounding parenchyma (P = 0.02). CONCLUSION: Non-invasive MR perfusion can detect changes in blood supply of precancerous lesions.

Detection of small hepatocellular carcinoma: comparison of dynamic enhancement magnetic resonance imaging and multiphase multirow-detector helical CT scanning.

AIM: To compare the gadolinium-enhanced multiphase dynamic magnetic resonance imaging (MRI) and multiphase multirow-detector helical CT (MDCT) scanning for detection of small hepatocellular carcinoma (HCC). METHODS: MDCT scanning and baseline MRI with SE T1-WI and T2-WI sequence combined with FMPSPGR sequence were performed in 37 patients with 43 small HCCs. Receiver operating characteristic (ROC) curves were plotted to analyze the results for modality. RESULTS: The areas below ROC curve (Az) were calculated. There was no statistical difference in dynamic enhancement MDCT and MRI. The detection rate of small HCC was 97.5%-97.6% on multiphase MDCT scanning and 90.7%-94.7% on MRI, respectively. The sensitivity of detection for small HCC on MDCT scanning was higher than that on dynamic enhancement MRI. The sensitivity of detection for minute HCC (tumor diameter < or = 1 cm) was 90.0%-95.0% on MDCT scanning and 70.0%-85.0% on MRI, respectively. CONCLUSION: MDCT scanning should be performed for early detection and effective treatment of small HCC in patients with chronic hepatitis and cirrhosis during follow-up.

[A comparative study of MRI manifestations and pathological changes in hepatocellular carcinoma treated by transcatheter arterial chemoembolization with lipiodol].

OBJECTIVES: To analyze the MRI manifestations and pathological changes of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) with lipiodol. METHODS: 23 patients with 31 HCC lesions treated by TACE underwent MRI examination within 1 week before their surgical resections. MRI was performed with SE sequence (T1WI and FSE T2WI) and FMPSPGR sequence dynamic multi-phase contrast scans. All resected specimens were cut into 5-10mm thick slices, corresponding to the same plane as that of MRI scans. The specimens were wholly embedded in paraffin, serial sections made and stained with hematoxylin and eosin. The MRI findings were thus compared with the pathology of the specimen sections. RESULTS: (1) MRI findings: In all 31 lesions, the signal intensity of lesions varied and was mostly heterogeneous on SE T1WI and T2WI images. Three lesions were inhomogeneous hyper-intensity and the other 28 lesions were iso- or hypo-intensity on FMPSPGR plain scannings. Twenty-two lesions were enhanced on early-phase dynamic scanning, and no enhancement was found in the other 9 lesions. Partial enhancement was also seen in 6 lesions on delay-phase dynamic scanning. (2) Pathologically, no coagulation necrosis was found in 2 specimens, but 6 lesions showed complete coagulation necrosis and 23 showed various degrees of it. The other pathological changes found included intra-tumoral hemorrhage (n=10), intra-lesional fibrotic septa formation (n=5), capsule-like fibrotic tissue proliferation around the lesions (n=12), inflammatory infiltration (n=28), focal mucoid degeneration (n=2), focal hyaline degeneration (n=2), and lipiodol retention (n=6). (3) Radiological-pathological correlation study: hyper-intense areas on T1WI corresponded to areas of coagulation necrosis with or without hemorrhage and of residual viable tumor; iso- and hypo-intense corresponded to areas of coagulation necrosis or residual viable tumor. Hyper-intense areas on T2WI corresponded to those of residual viable tumor or coagulation necrosis with hemorrhage, and iso-intense areas corresponded to those of coagulation necrosis, small residual viable tumor or intra-lesional fibrotic septa formation, and hypo-intense areas corresponded to those of coagulation necrosis or intra-lesional fibrotic septa formation. Areas of enhancement within the lesions on the early-phase dynamic-contrast images corresponded to areas of residual viable tumors, while areas of no enhancement were those of coagulation necrosis, hemorrhage, intra-lesional fibrotic septa formation or small residual viable tumors. Areas of enhancement on the delay-phase dynamic scanning were those of residual viable tumors or intra-lesional fibrotic septa formation, while no enhancement corresponded to the areas of residual viable tumors, coagulation necrosis, and hemorrhage. Areas of enhancement on the delay-phase dynamic scanning corresponded to those areas of fibrosis tissue or residual viable tumors. Inflammatory infiltration was found in areas of different signal intensity on MRI images. CONCLUSIONS: (1) Different pathological changes in HCCs after TACE are represented by various signal intensities on SE sequence images. The only area of hypo-intensity on T2WI has a specificity in representing coagulation necrosis. (2) FMPSPGR sequence dynamic MRI is superior to SE sequence in demonstrating and determining the necrosis and residual viable tumor. Enhanced areas within the lesions on the early-phase dynamic-contrast images represent residual viable tumors and the enhancement of capsule on early-phase dynamic-contrast images also represent subcapsular residual viable tumors. (3) MRI can demonstrate accurately the areas of necrosis and residual viable HCC tissues after TACE and evaluate the effect of TACE.

Vena cava 3D contrast-enhanced MR venography: a pictorial review.

Three-dimensional contrast-enhanced magnetic resonance venography (CE MRV) is a sensitive and accurate method for diagnosing vena cava pathologies. The commonly used indirect approach involves a nondiluted gadolinium contrast agent injected into an upper limb vein or, occasionally, a pedal vein for assessment of the superior or inferior vena cava. In our studies, a coronal 3D fast multi-planar spoiled gradient-echo acquisition was used. A pre-contrast scan was obtained to ensure correct coverage of the region of interest. We initiated contrast-enhanced acquisition 15 sec after the start of contrast agent injection and performed the procedure twice. The image sets were obtained during two 20-30-sec breath hold, with a breathing rest of 5-6 sec, to obtain the first-pass and delayed arteriovenous phases. For patients with Budd-Chiari syndrome, a third acquisition coinciding with late venous phase was collected to visualize the hepatic veins, which was carried out by one additional acquisition after a 5-6-sec breathing time. This review describes the clinical application of 3D CE MRV in vena cava congenital anomalies, superior and inferior vena cava syndrome, Budd-Chiari syndrome, peripheral vein thrombosis extending to the vena cava, pre-operational evaluation in portosystemic shunting and post-surgical follow-up, and road-mapping for the placement and evaluation of complications of central venous devices.

[Evaluation of early stage diffused liver lesions with MR functional diffusion-weighted imaging--an experimental study].

OBJECTIVE: To investigate the value of Diffusion-Weighted Imaging (DWI) in the diagnosis of early stage liver diffuse lesions. METHODS: Diethylnitrosamine (DEN) was used to induce liver lesions in rats. Sequential DWI studies were performed on the livers from 1 to 14 weeks after DEN was administered through drinking water. Comparing studies with a blank control group was set and pathohistological examinations of the livers were performed. RESULTS: No obvious routine MRI morphological change was found in either group during this period, but DWI demonstrated heterogeneous changes in the test group at the cirrhosis stage. There was no significant alteration of the apparent diffusion coefficient (ADC) value in the control group during this period (P > 0.05). The ADC values of the test group began to decline from the fifth week. Until the tenth week, the ADC value of the test group decreased drastically and when b = 300 s/mm2 statistic, the results showed an obvious difference between the two groups. There were also differences between the ADC values at the 10th, the 9th and the 1st weeks of the test group (P < 0.05). When b = 600 s/mm2 and 1000 s/mm2, significant differences were found after the sixth week between the two groups (P < 0.01). The main pathohistological liver change in the test group during the 1 to 4 week period after DEN was administered was swelling of hepatocytes; during the 5 to 8 week period it was fibrous tissues hyperplasia, and in the 9 to 14 week period it was cirrhotic nodule formation. CONCLUSION: MR functional DWI could detect liver diffuse lesions earlier than conventional MR imaging. Measurement of ADC value may be of use in early diagnosis of liver diffuse diseases and for monitoring the changes of the lesions.

In vivo detection of metabolic changes by 1H-MRS in the DEN-induced hepatocellular carcinoma in Wistar rat.

PURPOSE: To investigate the serial changes of the hepatic metabolites in a chemical-induced rat model of hepatocellular carcinoma (HCC) in vivo by a clinical 1.5 T MR scanner. METHODS: Diethyl nitrosamine (DEN) induced HCC model rats (n=60) and control rats (n=20) were included. From week 7 to week 20 after DEN administration, every other week 10-12 animals (8-9 treated and 2-3 controls) were randomly scanned before being sacrificed. According to the pathologic changes, the whole process of tumorigenesis was divided into early and late periods (week 7-13 and week 14-20, respectively). The serial hepatic changes were tested by both routine MRI and single voxel 1H-MRS and compared with pathological results. Point resolved spectroscopy sequence (PRESS) was used for the location in MRS. The integrations of lipid- and choline-containing metabolites were calculated and analyzed. RESULTS: All of the listed tests were fully finished in 66 rats (48 treated and 18 controls). Of the MRS curves, 65.2% (43/66) could be analyzed (mainly with resistant baseline with peaks appearing at right positions). From those qualified MRS curves, there were up to seven peaks which could be identified. The peaks of methylene lipids and methyl lipids were combined together in most cases and became the most notable component. The relative integrals of the combined lipid peak and that of the choline-containing compounds in different groups and stages were measured. Comparing with that of the controls of the same stage, the lipid of treated rats decreased in the late stage, and the choline-containing compounds increased in the same stage. Statistically significant differences were found (P<0.05) for the integrals of the lipid and the choline-containing metabolites between treated and controls in the late stage. CONCLUSIONS: Our initial studies for the integrals of the lipid compounds and the choline-containing metabolites might be useful for a better understanding of the metabolic activity of this DEN-induced rat HCC model.

CT perfusion at early stage of hepatic diffuse disease.

AIM: To determine the validity of the non-invasive method of CT perfusion (CTP) in rat model of hepatic diffuse disease. METHODS: Twenty-eight Wistar rats were divided into two groups. Liver diffuse lesions were induced by diethylnitrosamine in 14 rats of test group. Rats in control group were bred with pure water. From the 1st to 12th wk after the test group was intervened, both groups were studied every week with CTP. CTP parameters of liver parenchyma in different periods and pathologic changes in two groups were compared and analyzed. RESULTS: The process of hepatic diffuse lesions in test groups was classified into three stages or periods according to the pathologic alterations, namely hepatitis, hepatic fibrosis, and cirrhosis. During this period, hepatic artery flow (HAF) of control group declined slightly, mean transit time (MTT), blood flow (BF) and volume (BV) increased, but there were no significant differences between different periods. In test group, HAF tended to increase gradually, MTT prolonged obviously, BV and BF decreased at the same time. The results of statistical analysis revealed that the difference in the HAF ratio of test group to control group was significant. The ratio of BV and BF in test group to control group in stage of hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis was significantly different, but there was no significant difference between hepatitis and hepatic fibrosis. The main pathological changes in stage of hepatitis were swelling of hepatic cells, while sinusoid capillarization and deposition of collagen aggravated gradually in the extravascular Disse's spaces in stage of fibrosis and early stage of cirrhosis. CONCLUSION: The technique could reflect some early changes of hepatic blood perfusion in rat with liver diffuse disease and is valuable for their early diagnosis.

Magnetic resonance diffusion-weighted imaging in the diagnosis of diffuse liver diseases in rats.

BACKGROUND: The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage. METHODS: Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed. RESULTS: The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks (P > 0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm(2) (P < 0.05). At b value 600 and 1000 sec/mm(2), significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7 - 0.9) +/- (0.40 - 0.04) mm(2)/sec (b = 600) and (1.38 - 0.75) +/- (0.07 - 0.35) mm(2)/sec (b = 1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5 - 8 weeks and formation of cirrhotic nodules in 9 - 12 weeks. CONCLUSIONS: MR functional DWI could detect diffuse liver lesions earlier than conventional morphological imaging. ADC value as a marker for early diagnosis of diffuse liver lesions could also be used to inspect changes of the lesions.

[Portal vein involvement by hepatocellular carcinoma: diagnosis with three-dimensional contrast-enhanced MR angiography].

OBJECTIVE: To assess the accuracy of three-dimensional contrast-enhanced magnetic resonance angiography (3D CE MRA) in evaluating the portal vein involvement in patients with hepatocellular carcinoma. METHODS: Ninety patients with hepatocellular carcinoma underwent 3D CE MRA of the portal venous system, using a high-field 1.5 T MR machine and a body coil and using Gd-DTPA as contrast material, before hepatic surgery or interventional therapy. The acquired source images of the examination were reconstructed into 3D MRA image similar to that of conventional X-ray angiography. The patency of the main, right and left portal veins was evaluated. A total of 270 veins were assessed. The patency was classified as normal or involved. The involvement included encasement, occlusion, and tumor thrombosis. The 3D CE MRA diagnoses were compared with the surgical-pathologic, intra-operative sonographic, and X-ray portographic findings. RESULTS: 74 of the 75 involved portal veins and 188 of the 195 noninvolved portal veins confirmed by surgery or X-ray portography were detected by 3D CE MRA with an overall sensitivity rate of 99%, specificity rate of 96%, positive predictive value of 91%, and negative predictive value of 99%. The accuracy in diagnosis of the main portal vein was 100%. 3D CE MRA resulted in 7 false-positive interpretations involving 6 left portal veins and 1 right portal vein. One false-negative diagnosis was made on the right portal vein. CONCLUSION: 3D CE MRA is quite accurate in evaluation of portal vein involvement in patients with hepatocellular carcinoma.

Pancreatic adenocarcinoma: the different CT criteria for peripancreatic major arterial and venous invasion.

OBJECTIVE: To establish preliminarily the different diagnostic criteria for peripancreatic arterial and venous invasion in pancreatic carcinoma by comparing their multidetector-row computed tomography (MDCT) appearances with surgical exploration. METHODS: Among 101 patients with pancreatic carcinoma examined by MDCT, 54 candidates accepting surgery were preoperatively evaluated for vascular invasion based on CT signs (A-E): arterial embedment in tumor or venous obliteration; tumor involvement exceeding one-half of the circumference of the vessel; vessel wall irregularity; vessel caliber stenosis; teardrop superior mesenteric vein (SMV). The peripancreatic major vessels (n = 224) were examined carefully by surgeons during the operation. RESULTS: During surgical exploration, 78 vessels were found to be invaded. With sign A (B, C, or D) as the CT criterion for peripancreatic vascular invasion, the sensitivity of arterial and venous invasion was 66% (97%, 45%, or 41%) and 14% (49%, 63%, or 55%), respectively; the specificity of absence of arterial and venous invasion was 100% (91%, 99%, or 100%) and 100% (all 100%). In this study, there were 3 SMVs appearing teardrop (sign E), which were all confirmed to be invaded. CONCLUSIONS: It is recommended that the CT diagnostic criteria for arterial and venous invasion should be dealt with differently. The criteria of arterial invasion are the presence of sign A or the combination of sign B with one of signs C and D. The criteria of venous invasion are the presence of one of the following signs: sign A, sign B, sign C, sign D, and sign E.

Multiphase hepatic scans with multirow-detector helical CT in detection of hypervascular hepatocellular carcinoma.

BACKGROUND: Multirow-detector helical CT (MDCT) allows faster Z-axis coverage and improves longitudinal resolution to scan the entire liver. This study was to evaluate the value of multiphase hepatic CT scans using MDCT in diagnosing hypervascular hepatocellular carcinoma (HCC). METHODS: Multiphase hepatic CT scans in 40 patients were carried out with a Marconi Mx8000 MDCT scanner. The scans of early arterial phase (EAP), late arterial phase (LAP) and portal venous phase (PVP) were started at 21, 34 and 85 seconds after injection of contrast medium, respectively. The number of detected lesions was calculated in each phase. The density of the liver and tumor was greater than 1 cm for HCC, and the density of the liver and tumor in each phase was statistically calculated. RESULTS: A total of 61 lesions were found in the 40 patients, and lesions greater than 1 cm were seen in 47 cases. The density differences between the liver and tumor were statistically significant (P<0.05) at the LAP and EAP and between the LAP, EAP and PVP. In the 61 lesions, the detectability in the EAP, LAP and the double arterial phases (DAP) was 32%, 87%, and 94%, respectively. Significant difference was found between the LAP plus PVP and the EAP plus PVP; but no significant difference was observed between the DAP plus PVP and the LAP plus PVP. CONCLUSIONS: The utility of MDCT scan in the liver has optimized the protocol of arterial phase scan. MDCT is possible to scan the entire liver in a real arterial phase and it is very valuable in the detection of small HCC.

Postprocessing techniques of CT colonography in detection of colorectal carcinoma.

AIM: To evaluate the value of postprocessing techniques of CT colonography, including multiplanar reformation (MPR), virtual colonoscopy (VC), shaded surface display (SSD) and Raysum, in detection of colorectal carcinomas. METHODS: Sixty-four patients with colorectal carcinoma underwent volume scanning with spiral CT. MPR, VC, SSD and Raysum images were obtained by using four kinds of postprocessing techniques in workstation. The results were comparatively analyzed according to circumferential extent, lesion length and pathology pattern of colorectal carcinomas. All diagnoses were proved pathologically and surgically. RESULTS: The accuracy of circumferential extent of colorectal carcinoma determined by MPR, VC, SSD and Raysum was 100.0%, 82.8%, 79.7% and 79.7%, respectively. There was a significant statistical difference between MPR and VC. The consistent rate of lesion length was 89.1%, 76.6%, 95.3% and 100.0%, respectively. There was a statistical difference between VC and SSD. The accuracy of discriminating pathology pattern was 81.3%, 92.2%, 71.9% and 71.9%, respectively. There was a statistical difference between VC and SSD. MPR could determine accurately the circumference of colorectal carcinoma, Raysum could determine the length of lesion more precisely than SSD, VC was helpful in discriminating pathology patterns. CONCLUSION: MPR, VC, SSD and Raysum have advantage and disadvantage in detection of colorectal carcinoma, use of these methods in combination can disclose the lesion more accurately.

[The value of multislice spiral computed tomography in demonstrating the relationship between bronchus and peripheral lung cancer].

OBJECTIVE: To investigate the value of multislice spiral computed tomography (MSCT) in demonstrating the relationship between bronchus and peripheral lung cancer. METHODS: We prospectively performed volumetric targeted scans of 0.5 mm collimation with MSCT and reconstructed images of multiplanar reconstruction (MPR), curved multiplanar reformations (CMPR) and surface shaded display (SSD) in 53 peripheral lung cancers. The results were compared with macroscopic and microscopic specimens. RESULTS: (1) The third- to seventh-order branches of the bronchi were clearly shown in all patients by the designed protocol. CT demonstrated the tumor-bronchus relationship in 29 (96.7%) adenocarcinomas and 13 (76.5%) squamous-cell carcinomas. Statistic analysis showed that there was no significant difference between the two groups (chi(2) = 2.8, P > 0.05). (2) The tumor-bronchus relationship was identified as four types with MSCT. Type I: bronchus was obstructed abruptly by the tumor, type II: bronchus penetrated into the tumor with tapered narrowing and interruption, type III: bronchus lumen shown within tumor was patent and intact, type IV: bronchus ran at the periphery of the tumor with intact or narrowed lumen. (3) Type I was shown in 31 of 53 (58.5%) tumors with squamous-cell carcinoma slightly more common than adenocarcinoma. Type II and type III were seen equally in 8 of 53 (15.1%) tumors which occurred only in adenocarcinomas. Type IV was seen in 15 of 53 (28.3%) tumors with adenocarcinoma being slightly more frequent than squamous cell carcinoma. (4) The tumor at the fourth-order bronchus was more common in squamous cell carcinoma, whereas that at the fixth-order bronchus was more likely in adenocarcinoma. CONCLUSION: Volumetric targeted scan of ultra-thin section with MSCT and followed by MPR, CMPR and SSD reconstruction can greatly improve the manifestation of the bronchioles and accurately demonstrate the patterns of tumor-bronchus relationship, thereby reflecting pathologic changes to some extent.

[Small hepatocellular carcinoma: multiphase hepatic CT scan with a multidetector row helical CT scanner].

OBJECTIVES: To evaluate multiphase hepatic CT scan using multidetector row helical CT (MDCT) in detecting hypervascular small hepatocellular carcinoma (SHCC). METHODS: Multiphase hepatic CT scan in 75 patients with SHCC was carried out with Marconi MX8000 multidetector row helical CT scanner. The early arterial phase scan started at the 21th second after the injection of contrast medium, the late arterial phase scan started at the 34th second, and the portal venous phase started at the 80tieth second, six seconds every time. RESULTS: The study showed that the density values of 71 lesions between liver and SHCC were different significantly among the early arterial phase, the late arterial phase and the portal venous phase (F=3.327, P<0.05). Among the 91 lesions, the detectable rates of the early arterial phase and the late arterial phase were 45.1% and 83.5%, respectively. The rate of double arterial phases was 92.3%. The rates increased to 94.5% and 97.8%, when the late arterial phase combined with the portal venous phase and the double arterial phase combined with the portal venous phase. CONCLUSION: The utility of MDCT with faster speed, thinner slice and multiphases scanning has improved the opportunity of detecting hypervascular hepatocellular carcinoma.