Quantitative measurement of hepatic portal perfusion by multidetector row CT with compensation for respiratory misregistration

Our purpose was to determine whether hepatic portal perfusion assessed by multidetector row CT using compensation for respiratory misregistration can predict the severity of chronic liver disease. We carried out dynamic CT in 43 patients (chronic hepatitis: n=9; cirrhosis: n=24; normal liver: n=10). In this series, 20 patients had liver tumours. The CT protocol was designed to avoid respiratory artefacts and included two interscan breathing periods during the study. To compensate for respiratory misregistration, image sets in the same z-axis position were acquired from four-slice data on each scan, and the portal perfusion calculations were made according to the maximum slope method. Portal perfusion was compared with and without compensation for respiratory misregistration, and the different types of hepatic disease. In the liver tumour patients in particular, portal perfusion was compared with the degree of hepatic fibrosis in the liver sections. Portal perfusion in the patients without compensation for respiratory misregistration (1.10 ml min(-1)ml(-1)) was higher than that of those with compensation (0.99 ml min(-1)ml(-1); p=0.036). Hepatic portal perfusion of patients with chronic hepatitis (0.97 ml min(-1)ml(-1)) and liver cirrhosis (0.88 ml min(-1)ml(-1)) was less than that of patients with normal liver (1.32 ml min(-1)ml(-1); p=0.03, 0.001). Moderate correlation was seen between portal perfusion and the percentage of fibrosis in patients with liver tumours (r=0.55). Hepatic portal perfusion obtained by multidetector row dynamic CT using compensation for respiratory misregistration has the potential to improve non-invasive assessment of the degree of chronic liver disease.     

运用CT动态灌注成像技术测定肝脏血流量的临床研究

目的 探讨CT灌注成像的测定方法和技术原理,以及肝硬化程度与肝脏血流量动态变化关系。资料与方法 肝硬化患者27例,其中Child A级12例,Child B级10例,CMld C级5例。对照组为无肝脏疾病者18例。选取同时含有肝脏、脾、主动脉和门静脉的层面进行CT动态增强扫描,绘制感兴趣区时间-密度曲线(TDC),计算肝脏血流量各参数。结果 (1)肝硬化患者的肝动脉灌注量(HAP)、门静脉灌注量(PVP)和总肝血流量(THBF)均较正常组降低,平均通过时间(MTT)较正常组延长。(2)肝硬化程度不同时,部分肝血流灌注参数存在显著性差异。(3)脾灌注量和门静脉灌注量呈正相关。结论 (1)肝脏CT灌注成像可定量测定肝血流量参数。(2)肝硬化时肝脏血流灌注的变化与疾病的严重程度相关。     

Effects of TIPS on liver perfusion measured by dynamic CT

OBJECTIVE: Our aim was to measure the arterial, portal venous, and total perfusion of the liver parenchyma with dynamic, single-section CT in patients with liver cirrhosis before and after transjugular intrahepatic portosystemic shunt (TIPS) placement and to compare the results with normal values. SUBJECTS AND METHODS: Perfusion of the liver parenchyma was measured in 24 healthy volunteers and 41 patients with liver cirrhosis using dynamic single-section CT. Seventeen patients underwent TIPS placement, and CT measurements were repeated within 7 days. CT scans were obtained at a single level comprising the liver, spleen, aorta, and portal vein. Scans were obtained over a period of 88 sec (one baseline scan followed by 16 scans every 2 sec and eight scans every 7 sec) beginning with the injection of a contrast agent bolus (40 mL at 10 mL/sec). Parenchymal and vascular contrast enhancement was measured with regions of interest, and time-density curves were obtained. These data were processed with a pharmaco-dynamic fitting program (TopFit), and the arterial and portal venous component and the total perfusion of the hepatic parenchyma were calculated (milliliters of perfusion per minute per 100 mL of tissue). RESULTS: Mean normal values for hepatic arterial, portal venous, and total perfusion were 20, 102, and 122 mL/min per 100 mL, respectively. In patients with cirrhosis before TIPS, mean hepatic arterial, portal venous, and total perfusion was 28, 63, and 91 mL/min per 100 mL, respectively, which was statistically significant for all values (p <0.05). After TIPS, hepatic perfusion increased to a mean value of 48, 65, 113 mL/min per 100 mL for arterial (p <0.01), portal venous, and total (p=0.011) perfusion, respectively. CONCLUSION: In patients with cirrhosis, the hepatic arterial perfusion increased, whereas portal venous and total perfusion decreased compared with that of healthy volunteers. TIPS placement caused a statistically significant increase of the hepatic arterial and total hepatic perfusion. The portal venous parenchymal perfusion remained unchanged.     

Computed tomography perfusion of the liver: assessment of pure portal blood flow studied with CT perfusion during superior mesenteric arterial portography

Purpose: To quantitatively assess the portal component of hepatic blood flow using computed tomography (CT) perfusion studies during superior mesenteric arterial portography. Material and Methods: Thirty-four patients with hepatocellular carcinoma and liver cirrhosis (LC) and 13 patients with liver metastasis without chronic liver disease were enrolled in this study. Ten milliliters of a non-ionic contrast medium (150 mgI) was injected at a rate of 5 ml/s via a catheter placed in the superior mesenteric artery. Single-slice cine CT images at the level of the main trunk or the right/left main trunk of the portal vein were acquired over 40 s. The deconvolution method was then used on these CT images to measure blood flow (BF), blood volume (BV), and mean transit time (MTT) in (a) liver parenchyma in patients with HCC and liver cirrhosis; (b) liver parenchyma in patients with liver metastasis without cirrhosis; (c) directly in the HCC; and (d) directly in one of the metastases. Results: In 34 LC patients (a), BF, BV, and MTT in the liver parenchyma were 44.7±24.5 ml/min/100 g, 3.9±2.4 ml/100 g, and 10.9±5.5 s, respectively. In 13 patients without cirrhosis (b), BF, BV, and MTT in the liver parenchyma were 89.6±52.0 ml/min/100 g, 6.3 ±3.2 ml/100 g, and 8.7±3.6 sec, respectively. A significant difference in BF and BV was seen in patients with liver cirrhosis compared to those without cirrhosis. BF, BV, and MTT measured directly in HCC (c) were 6.5±4.5 ml/min/100 g, 0.4±0.4 ml/100 g, and 3.0±3.1 sec respectively, and BF, BV, and MTT in liver metastases (d) were 19.3 ± 21.7 ml/min/100 g, 0.6±0.8 ml/100 g, and 1.8±1.6 s, respectively. Conclusion: CT perfusion studies during superior mesenteric arterial portography allow quantitative assessment of pure portal blood flow in the liver.     

Hepatic enhancement in multiphasic contrast-enhanced MDCT: comparison of high- and low-iodine-concentration contrast medium in same patients with chronic liver disease

OBJECTIVE: The aim of this study was to evaluate the degree of hepatic enhancement and image quality in patients with cirrhosis or chronic hepatitis who underwent multiphasic contrast-enhanced dynamic imaging on MDCT at least twice using standard (300 mg I/mL) and higher (370 mg I/mL) iodine concentrations in contrast medium during follow-up periods. MATERIALS AND METHODS: This study included 20 patients with chronic liver diseases who underwent at least two multiphasic contrast-enhanced dynamic MDCT examinations using 100 mL of standard (300 mg I/mL = group A) and higher (370 mg I/mL = group B) iodine concentrations in contrast medium. After we obtained unenhanced CT scans, we performed multiphasic scanning at 30 sec (arterial phase), 60 sec (portal phase), and 180 sec (late phase) after the start of contrast medium injection. The CT values of hepatic parenchyma, abdominal aorta, and portal vein were measured. The mean enhancement value was defined as the difference in CT values between unenhanced and contrast-enhanced images. Visual image quality was also assessed on the basis of the degree of hepatic and vascular enhancement, rated on a 4-point scale. RESULTS: The mean hepatic parenchyma enhancement values in group B was significantly greater (p < 0.001) than those in group A during the portal phase (43.8 +/- 8.2 H vs 36.2 +/- 7.3 H) and the late phase (33.7 +/- 7.0 H vs 27.3 +/- 3.9 H), but the difference on the arterial phase images between the two groups (9.4 +/- 3.2 H vs 8.3 +/- 2.5 H) was not significant. The mean aorta-to-liver contrast during the arterial phase in group B was significantly higher (p < 0.001) than that in group A (236 +/- 40 H vs 193 +/- 32 H). For qualitative analysis, the mean visual scores for hepatic parenchyma and vasculature enhancement in group B were significantly higher than those in group A in arterial phase (p < 0.018), portal phase (p < 0.0001), and late phase (p < 0.0001). CONCLUSION: In the same patients with chronic liver diseases, a higher iodine concentration (370 mg I/mL) in the contrast medium improves contrast enhancement of liver parenchyma in the portal phase and late phase images, improves overall image quality, and helps improve diagnostic accuracy for liver diseases on multiphasic contrast-enhanced dynamic MDCT.     

CT perfusion of the liver during selective hepatic arteriography: pure arterial blood perfusion of liver tumor and parenchyma

PURPOSE: To quantify pure arterial blood perfusion of liver tumor and parenchyma by using CT perfusion during selective hepatic arteriography. METHODS: A total of 44 patients underwent liver CT perfusion study by injection of contrast medium via the hepatic artery. CT-perfusion parameters including arterial blood flow, arterial blood volume, and arterial mean transit time in the liver parenchyma and liver tumor were calculated using the deconvolution method. The CT-perfusion parameters and vascularity of the tumor were compared. RESULTS: A complete analysis could be performed in 36 of the 44 patients. For liver tumor and liver parenchyma, respectively, arterial blood flow was 184.6 +/- 132.7 and 41.0 +/- 27.0 ml/min/ 100 g, arterial blood volume was 19.4 +/- 14.6 and 4.8 +/- 4.2 ml/100 g, and arterial mean transit time was 8.9 +/- 4.2 and 10.2 +/- 5.3 sec. Arterial blood flow and arterial blood volume correlated significantly with the vascularity of the tumor; however no correlation was detected between arterial mean transit time and the vascularity of the tumor. CONCLUSION: This technique could be used to quantify pure hepatic arterial blood perfusion.     

Assessment of hepatic perfusion parameters with dynamic MRI.

Quantification of hepatic perfusion parameters greatly contributes to the assessment of liver function. The purpose of this study was to describe and validate the use of dynamic MRI for the noninvasive assessment of hepatic perfusion parameters. The signal from a fast T(1)-weighted spoiled gradient-echo sequence preceded by a nonslice-selective 90 degrees pulse and a spoiler gradient was calibrated in vitro with tubes filled with various gadolinium concentrations. Dynamic images of the liver were obtained after intravenous bolus administration of 0.05 mmol/kg of Gd-DOTA in rabbits with normal liver function. Hepatic, aortic, and portal venous signal intensities were converted to Gd-DOTA concentrations according to the in vitro calibration curve and fitted with a dual-input one-compartmental model. With MRI, hepatic blood flow was 100 +/- 35 mL min(-1) 100 mL(-1), the arterial fraction 24 +/- 11%, the distribution volume 13.0 +/- 3.7%, and the mean transit time 8.9 +/- 4.1 sec. A linear relationship was observed between perfusion values obtained with MRI and with radiolabeled microspheres (r = 0.93 for hepatic blood flow [P < 0.001], r = 0.79 for arterial blood flow [P = 0.01], and r = 0.91 for portal blood flow [P < 0.001]). Our results indicate that hepatic perfusion parameters can be assessed with dynamic MRI and compartmental modeling.     

Quantitative perfusion map of malignant liver tumors, created from dynamic computed tomography data

RATIONALE AND OBJECTIVES: To apply perfusion computed tomography (CT) technique to variable malignant liver tumors, and to define the usefulness of quantitative color mapping. MATERIALS AND METHODS: Perfusion CT images were created for 36 malignant liver tumors in 28 patients (age, 66.4 +/- 10.1 years; range, 48-85) with metastatic liver tumors (n = 17; nine colorectal carcinomas, eight other malignant tumors) and hepatocellular carcinomas (n = 11). A single-slice dynamic CT was performed after an intravenous bolus injection of 40 mL of contrast material (320 mgI/mL) with 8 mL/sec. The parameters were calculated pixel-by-pixel using maximum slope method, and quantitative maps of arterial and portal perfusion were created. In four patients who underwent transcatheter arterial chemoembolization, perfusion CT was performed before and after transcatheter arterial chemoembolization. RESULTS: In all patients, liver tumors were shown as hypervascular lesions on arterial perfusion CT. The average arterial perfusion value of the metastatic tumors from the colorectal carcinomas was 0.67 +/- 0.33 mL/min/mL, and that of hepatocellular carcinomas was 0.94 +/- 0.26 mL/min/mL (P = .03). The other metastatic tumors from various primary tumors showed a wide range (0.19-1.45 mL/min/mL) of arterial perfusion. Arterial perfusion of the liver tumors was obviously decreased after successful transcatheter arterial chemoembolization. In 12 of 15 tumors, in which portal perfusion CT images could be created, region-of-interest analysis showed no portal perfusion in the tumors. In two cases, decreased portal perfusion in the segments, which malignant tumors involved, was demonstrated. CONCLUSION: Perfusion CT can provide quantitative information about arterial and portal perfusion of liver tumors, combined with good anatomic detail in one image. This technique has a potential to evaluate the angiogenesis of liver tumors, to show secondary changes in perfusion, such as decreased portal perfusion in apparently normal liver adjacent to metastases, and to monitor the therapeutic response in vivo.     

"Congestion index" of the portal vein

The "congestion index" is used to mean the ratio between the cross-sectional area (cm2) and the blood flow velocity (cm/sec) of the portal vein, as determined by a duplex Doppler system. The indices as determined in normal subjects and patients with liver disease were as follows: normal subjects (n = 85), 0.070 +/- 0.029 cm X sec; acute hepatitis (n = 11), 0.071 +/- 0.014 cm X sec; chronic active hepatitis (n = 42) 0.119 +/- 0.084 cm X sec; cirrhosis (n = 72), 0.171 +/- 0.075 cm X sec; and idiopathic portal hypertension (n = 11), 0.180 +/- 0.107 cm X sec. There was a statistically significant difference between the congestion indices from the normal subject group and indices obtained from patients with chronic hepatitis, cirrhosis, and idiopathic portal hypertension. A weak positive correlation was obtained between the congestion index and the portal venous pressure, measured simultaneously through a percutaneously placed catheter (n = 64, r = 0.45, p less than 0.01). It is suggested that the congestion index reflects the pathophysiological hemodynamics of the portal venous system in portal hypertension.     

Hepatic transit time of ultrasound contrast in biopsy characterized liver disease

PURPOSE: To study the hepatic transit time of an ultrasound contrast agent in patients with liver disease, and to evaluate the mechanism(s) of the well-established shorter cubital vein to hepatic vein transit time in cirrhosis. MATERIAL AND METHODS: Thirty-four patients scheduled for Menghini liver biopsy were studied by ultrasound after injection of 2.5 g Levovist (Schering, Berlin, Germany) into an arm vein. The time from injection until the first appearance of contrast echoes in the hepatic artery and hepatic veins was registered. Hepatic transit time was the difference between the two. RESULTS: Biopsy showed cirrhosis in 9 patients, other diffuse hepatic pathology in 23 patients, and normal liver in 2 patients. Mean hepatic vein arrival time was earlier in cirrhosis than in other liver disease (19.4 s versus 26.0 s; P = 0.013), and hepatic transit time was shorter (6.6 s versus 11.6 s; P = 0.024). A hepatic transit time <10 s was found in all patients with cirrhosis, but also in 10 of 23 patients with other liver pathology. CONCLUSION: Hepatic transit time measurement could not be used to distinguish between cirrhosis and other hepatic pathology, but a transit time = 10 s excluded cirrhosis. The earlier hepatic vein arrival time in cirrhosis is apparently mainly caused by intrahepatic shunting rather than by early arrival of contrast to the liver.     

Diagnosis of liver cirrhosis by transit-time analysis at contrast-enhanced ultrasonography

Purpose

The aims of this prospective study were to evaluate analysis of sulfur-hexafluoride-filled microbubble contrast agent (Sonovue) transit times as a tool for differentiating liver cirrhosis from the noncirrhotic stage of liver disease and to compare its performance with that of conventional B-mode and Doppler ultrasonography (US).

Materials and methods

Contrast-enhanced hepatic ultrasonography with the US contrast agent Sonovue was performed on 38 patients with diagnoses of hepatic cirrhosis based on unequivocal clinical signs or liver biopsy findings (Child-Pugh classes A in 19, B in 16 and C in three), 31 patients with noncirrhotic diffuse liver disease (biopsy confirmed) and 14 controls without diffuse liver disease. Time curves of hepatic-vein signal intensity were analysed using objective criteria to determine the time of enhancement onset (hepatic-vein arrival time) and peak enhancement (hepatic-vein peak enhancement). Accuracy in diagnosing cirrhosis was compared with that based on B-mode and Doppler data.

Results

Hepatic-vein arrival time in cirrhotic patients was significantly shorter (p<0.01) than in noncirrhotic (chronic liver disease and controls) patients. Peak enhancement times in these three groups were not significantly different. An arrival-time cutoff of 17 s distinguished cirrhotic from noncirrhotic patients with high accuracy (100% sensitivity, 93.3% specificity, positive and negative predictive values 92.6% and 100%, respectively) and excellent reproducibility (kappa coefficients of 1.0 and 0.93 for intraand interobserver agreement). Contrast-enhanced US showed better sensitivity than the B-mode and Doppler data.

Conclusions

Analysis of the time of onset of US contrast enhancement of the hepatic vein appears to be a potentially useful noninvasive supplement to conventional sonography and Doppler in the follow-up of patients with chronic diffuse liver disease.     

Doppler sonography of hemodynamic changes of the inferior mesenteric artery in inflammatory bowel disease: preliminary data.

OBJECTIVE: To our knowledge, Doppler data for the inferior mesenteric artery are currently restricted to healthy patients. The present study was conducted to evaluate changes in inferior mesenteric artery flow in patients with inflammatory bowel disease. SUBJECTS AND METHODS: Doppler sonography of the inferior mesenteric artery was prospectively performed in 24 patients with Crohn's disease (active, n = 15; inactive, n = 9), in 22 patients with ulcerative colitis (active, n = 14; inactive, n = 8), and in 40 healthy controls. Disease activity was determined with clinical and laboratory indicators (medical history, physical examination, laboratory data, and endoscopy with histology). Flow velocity, pulsatility index, and estimated flow volume were measured in all patients and compared with the corresponding values for control subjects. Hemodynamic parameters were then correlated with location of disease (small bowel and right and proximal transverse colon versus distal transverse and left colon) and disease activity or inactivity. RESULTS: Among patients with active disease, inferior mesenteric artery flow was significantly greater in those with left colon involvement (group 1, 20 patients) than in patients with involvement of the small bowel or right colon (group 2, nine patients) and in control subjects. Median flow values for group 1 were peak systolic velocity, 1.96+/-0.57 m/sec; mean velocity, 0.63+/-0.25 m/sec; minimum velocity, 0.17+/-0.20 m/sec; pulsatility index, 3.07+/-1.24; and estimated flow volume, 0.40+/-0.17 l/min. Median flow values for group 2 were peak systolic velocity, 1.27+/-0.56 m/sec; mean velocity, 0.29+/-0.14 m/sec; minimum velocity, 0.06+/-0.10 m/sec; pulsatility index, 4.71+/-0.98; and estimated flow volume, 0.14+/-0.11 l/min. Median flow values for control subjects were peak systolic velocity, 1.41+/-0.48 m/sec; mean velocity, 0.43+/-0.19 m/sec; minimum velocity, 0.10+/-0.16 m/sec; pulsatility index, 3.49+/-0.49; and estimated flow volume, 0.13+/-0.06 l/min. Compared with control subjects, patients with acute disease involving the left colon (group 1) presented increases in flow velocity (systolic velocity, p < .001; minimum velocity, p = .01; mean velocity, p < .001) and estimated flow volume (p < .001) and a decreased pulsatility index (p = .01). A significant increase in inferior mesenteric artery flow was also found when group 1 patients were compared with those of group 2 (active disease affecting the small bowel and right colon) and group 3 (13 patients with quiescent disease of the left colon). CONCLUSION: In this preliminary study, active inflammation of the left colon in patients with Crohn's disease or with ulcerative colitis was associated with a substantial increase in inferior mesenteric artery flow that could be seen on Doppler sonography.     

Computed tomography perfusion using first pass methods for lung nodule characterization

OBJECTIVE: To evaluate computed tomography (CT) perfusion using first pass methods for lung nodule characterization. METHODS: Fifty-seven patients with 51 malignant and 6 benign nodules underwent first-pass, dynamic contrast-enhanced-CT (50 mL, 3-5 mL/s.). Kinetic analysis tools were CT Perfusion 3 (GEMS, Milwaukee, WI), a distributed parameter model approach, yielding blood volume (BV; mL/100 g), blood flow (BF; mL/min/100 g), mean transit time (1/s), and permeability surface area (mL/min/100 g), and an in-house Patlak-style analysis yielding fractional BV (mL/100 g) and an estimate of extraction (Kps, mL/100 g/min). RESULTS: CT Perfusion 3 parameters in malignant and benign nodules were: mean transit time 10.1 +/- 0.9 1/s versus 11.1 +/- 3.1 1/s (ns), permeability surface 23.3 +/- 9.1 mL/min/100 g versus 19.6 +/- 10.3 mL/min/100 g (ns), BF 111.3 +/- 8.7 mL/min/100 g versus 39.1+/- 5.7 mL/min/100 g (P < 0.001), BV 9.3+/- 0.7 mL/100 g versus 4.1 +/- 1.1 mL/100 g (P < 0.002); Patlak parameters were: Kps 13.3 +/- 1.2 mL/100 g/min versus 3.9 +/- 0.8 mL/100 g/min (P < 0.001), BV 8.4 +/- 0.8 mL/100 g versus 3.6 +/- 1.3 mL/100 g (P < 0.01). The two kinetic methods show good agreement for BV estimation (Bland-Altman plot). The limits of agreement (bias +/-2 standard deviation of bias) were 1.2 +/- 5.3 mL/100 g. CONCLUSION: CT Perfusion using first pass modeling appears feasible for lung nodule characterization. Given the short acquisition duration used, weaknesses of the modeling methods are exposed. Nonetheless, microvascular characterization in terms of BF, BV, or Kps appears useful in distinguishing malignant from benign nodules.     

Hepatic bile entry into and transit pattern within the gallbladder lumen: a new quantitative cholescintigraphic technique for measurement of its concentration function.

The aim of the project was to study hepatic bile entry into and the transit pattern within the gallbladder lumen during fasting and to introduce a new quantitative scintigraphic test for measurement of its concentration function. METHODS: Each of 10 control subjects and 10 chronic acalculous cholecystitis (CAC) patients received 111-185 MBq 99mTc-mebrofenin as a hepatic bile marker. Gamma-camera image data were collected in the anterior view on a 128 x 128 x 16 computer matrix at 1 frame per minute for 60 min for the hepatic phase and 30 min for the gallbladder phase. The radiolabeled hepatic bile area within the gallbladder lumen was traced, and the net transit area and transit time were noted. The hepatic bile transit rate was calculated (as mm2/min) and normalized to 1,000 mm2 of the anterior gallbladder area. The cholecystokinin-8-induced ejection fraction was calculated nongeometrically using counts. RESULTS: Hepatic bile entered the gallbladder continuously during fasting with a mean +/- SD of 71% +/- 20% in control subjects and 59% +/- 27% in CAC patients, which were not significantly different (P > 0.05). The maximum frontal gallbladder area was 1,699 mm2 in control subjects and 1,610 mm2 in CAC patients (P > 0.05). Radiolabeled hepatic bile entered the gallbladder first along its central long axis in both groups, at a mean of 15 min and 16 min, respectively, and traveled toward the periphery in a lamellar fashion at a normalized mean rate of 38 mm2/min and 40 mm2/min in control subjects and CAC patients, respectively. The mean ejection fraction of 17% in CAC patients was significantly lower than the mean value of 56% in control patients (P < 0.00001). CONCLUSION: Hepatic bile enters the gallbladder continuously during fasting. In patients with CAC, the gallbladder maintains the normal concentration function but the contraction and emptying are reduced significantly. This new cholescintigraphic technique enables measurement of both functions sequentially with a single dose of 99mTc-mebrofenin.     

CT灌注扫描在肝肿瘤的临床应用

目的 研究肝脏良恶性肿瘤多层螺旋CT各灌注参数的改变和良恶性肿瘤的鉴别诊断。资料与方法 100名受检者行肝血流的CT灌注扫描,其中良性肿瘤组15例,恶性肿瘤组81例,正常组4例。应用去卷积算法模式计箅相应病变区域的血流量（BF）、血容量（BV）、平均通过时间（MTT）、毛细血管通透性（PS）、肝动脉指数（HPI）和肝动脉灌注量（HAP）。根据不同肿瘤的相关参数图来评价良恶性肿瘤血流动力学状态。结果 81例肝脏恶性肿瘤患者HPI、BF及HAP明显高于良性肿瘤及正常组织,而MTT却明显降低;BV和PS值与良性肿瘤及正常组织无显著差异。结论 灌注参数HPI、BF、MTT和HAP可有效地评价肝脏肿瘤的血流状态,在肝脏良恶性肿瘤的鉴别诊断中有重要的临床应用价值。     

肝硬化患者肺微循环多层螺旋CT灌注研究

目的:采用MSCT灌注成像技术研究肝硬化患者肺部微循环灌注参数的变化。材料和方法:对20例正常对照组、24例代偿期肝硬化组和19例失代偿期肝硬化组行16层螺旋CT肺部同层动态增强扫描后,在工作站上使用perfusion3软件包对扫描数据进行处理,得出感兴趣区的时间-密度曲线(time-density curve,TDC)和各灌注参数值,包括血流量(blood flow,BF)、血容量(blood volume,BV)、对比剂平均通过时间(mean transit time,MTT)和表面渗透积乘积(permeability surface area product,PS)。采用SPSS11.5软件包对上述数据进行统计学分析。结果:BF、BV值在各组的总体均数差别有统计学意义(P<0.01)。失代偿期肝硬化组的BF、BV值较正常对照组和代偿期肝硬化组都明显增加,组间差别有统计学意义(P<0.01)。代偿期肝硬化组的BF、BV值与正常对照组比较,组间差别无统计学意义(P>0.05)。MTT值各组的总体均数间差别有统计学意义(0.05>P>0.01)。失代偿期肝硬化组的MTT值较正常对照组和代偿期肝硬化组减少,组间差别有统计学意义(0.05>P>0.01)。PS值各组间差别无统计学意义(P>0.05)。结论:MSCT肺部微循环灌注成像技术可反映肝硬化患者病情程度。     

肝脏灌注成像的CT扫描方法及应用价值

目的:探讨单层CT动态增强扫描测定肝硬化肝脏血流量的扫描方法及其应用价值。方法:15例经临床、实验室及B超检查诊断为肝硬化的患者,其中ChildB级患者10例,ChildC级患者5例。对照组为13例无肝脏疾病的患者。所有患者均选取同时含有肝脏、脾脏、主动脉和门静脉的层面进行单层CT动态增强扫描,绘制感兴趣区时间密度曲线,计算各血流灌注参数。结果:单层CT动态增强扫描测量肝组织的肝动脉灌注量(HAP)、门静脉灌注量(PVP)、总肝血流量(THBF)和肝动脉灌注指数(HPI)。正常组的HAP、PVP、THBF和HPI分别为(0.28±0.10)ml/min·ml、(1.18±0.40)ml/min·ml、(1.46±0.44)ml/min·ml和(19.73±5.81)%;肝硬化组的HAP、PVP、THBF和HPI分别为(0.23±0.11)ml/min·ml、(0.61±0.25)ml/min·ml、(0.84±0.32)ml/min·ml和(27.16±12.75)%。结论:肝脏单层CT灌注成像,可定量测定各项肝脏血流灌注参数,对肝硬化患者的量化诊断有一定的参考价值。     

肝硬化基础上肝癌肝血流变化功能CT灌注成像研究

目的对正常肝实质、肝硬化和肝硬化基础上肝癌患者的64层螺旋CT灌注成像进行分析,评价多层螺旋CT灌注成像对肝硬化基础上肝癌肝血流变化的诊断价值。资料与方法无肝脏疾病的30例作为对照组。实验组包括49例肝硬化疾病患者,其中27例确诊为原发性肝癌(HCC)。所有研究对象知情同意后,选择癌灶中心层面或肝门层面行CT灌注扫描,采用低剂量扫描:120 kV,60 mA,扫描范围为40 mm。以4～5 ml/s流率,按照1.0ml/kg体重用量静脉团注对比剂。在注入对比剂5 s后行50 s连续的扫描,360°旋转/s,5 mm层厚进行图像重组,矩阵大小512×512像素。利用去卷积数学模型获得与肝血流变化相关的灌注参数值:肝血流量(HBF),肝血容量(HBV),肝动脉灌注分数(HAF),肝动脉灌注量(HAP),门静脉灌注量(HPP)。对不同的感兴趣区进行三次灌注参数测量后取平均值进行灌注结果分析。感兴趣区包括:对照组的正常肝实质、癌灶边缘区、癌灶周围的肝实质和无癌灶的肝硬化肝实质。结果与对照组灌注参数比较,癌周围肝实质的HBF、HAP、HPP、HBV及癌灶边缘区的HBF、HAP、HPP有统计学差异(P<0.05)。与对照组相对应灌注参数比较,癌周的HAP、HPP及对照组的HBF、HAP、HPP有统计学差异(P<0.05)。与癌边缘区HAF对比,癌灶周围肝实质、对照组和无癌灶的肝硬化组均有统计学差异(P<0.05)。对照组和无癌灶的肝硬化组间灌注参数无明显差异(P>0.05)。结论 CT灌注成像能很好地反映肝硬化基础上肝癌的肝血流变化信息,为肝血流动力学变化的影像研究提供新的方法。     

Hepatic flow parameters measured with MR imaging and Doppler US: correlations with degree of cirrhosis and portal hypertension

PURPOSE: To determine the correlations between hemodynamic parameters of hepatic flow measured with magnetic resonance (MR) imaging and Doppler ultrasonography (US) and the severity of cirrhosis and portal hypertension. MATERIALS AND METHODS: Forty-six patients referred for measurements of portal venous pressure (three with normal liver, 12 with chronic hepatitis, and 31 with cirrhosis [10 with Child-Pugh class A cirrhosis; 13 with class B cirrhosis; and eight with class C cirrhosis]) were included in the study. Apparent liver perfusion, apparent arterial and portal perfusion, portal fraction, distribution volume, and mean transit time were measured with dynamic contrast material-enhanced MR imaging. Portal velocity, portal flow, congestion index, right hepatic artery resistance index, and modified hepatic index were measured with Doppler US. Results in patients with cirrhosis and those without cirrhosis were compared with the Wilcoxon rank sum test. Correlations were assessed with Spearman rank correlation coefficients. RESULTS: With MR imaging, all flow parameters except distribution volume were significantly different between patients with and those without cirrhosis (P <.05). There was a significant correlation between all flow parameters measured with MR imaging and portal pressure (P <.02). Apparent arterial (P =.024) and portal (P <.001) perfusion, portal fraction (P <.001), and mean transit time (P =.004) were correlated with Child-Pugh class. Flow parameters measured with Doppler US did not differ significantly between patients with and those without cirrhosis. Only right hepatic arterial resistance (P <.007) and portal flow (P <.043) were weakly (r < 0.7) correlated with portal pressure. No Doppler US parameter was correlated with Child-Pugh class. CONCLUSION: Hepatic flow parameters measured with MR imaging correlate with the severity of cirrhosis and portal hypertension. Doppler US parameters are only weakly correlated with portal pressure.     

Advanced gastric cancer and perfusion imaging using a multidetector row computed tomography: correlation with prognostic determinants.

OBJECTIVE: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. MATERIALS AND METHODS: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti-CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student's t-test and the Spearman rank correlation were performed in SPSS 11.5. RESULTS: The mean perfusion values and MVD for tumors were as follows: BF (48.14+/-16.46 ml/100 g/min), BV (6.70+/-2.95 ml/100 g), MTT (11.75+/-4.02 s), PS (14.17+/-5.23 ml/100 g/min) and MVD (41.7+/-11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). CONCLUSION: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer.