Evaluation of intraportal venous flow distribution by unenhanced MR angiography using three‐dimensional fast spin‐echo with a selective tagging pulse: Efficacy of subtraction of tag‐on and tag‐off images acquired during a single breath‐hold

Purpose

To evaluate the efficacy of subtracted MR images from two sets of unenhanced three‐dimensional (3D) MR angiography data (tag‐on and tag‐off images) acquired simultaneously during a single breath‐hold in assessing the intraportal venous flow distribution to the distal branches from the superior mesenteric vein (SMV) and the splenic vein (SpV).

Materials and Methods

Tag‐on and tag‐off MR images during a single breath‐hold were obtained in 25 normal subjects. Tagging pulse was placed on the SMV or SpV separately to study inflow correlation of tagged blood into the portal vein.

Results

On the MR images tagged on the SMV, the mean ratings of visibility of tagged blood flow on the subtracted images were significantly higher (P = 0.016–0.0001) than those on the source images in almost all branches except second‐ordered left portal vein (P = 0.096). On the subtracted MR images tagged on SMV, the tramline (16 of the 25 subjects) was the most common distribution pattern of the tagged blood inflow in the main portal vein.

Conclusion

Subtracted MR images from two sets of unenhanced 3D MR angiography data (tag‐on and tag‐off images) acquired simultaneously would be effective to show the blood flow distribution of tagged blood into the portal vein and distal branches from SMV and SpV under the physiological condition without contrast injections. J. Magn. Reson. Imaging 2009;29:1224–1229. © 2009 Wiley‐Liss, Inc.     

Streamlined flow in the portal vein: demonstration with MR angiography

PURPOSE: To demonstrate whether streamlining of the portal vein flow exists by evaluating the relative distribution of blood flowing from the superior mesenteric vein (SMV) and splenic vein (SV) into the portal venous system. MATERIALS AND METHODS: Fifteen healthy adult volunteers underwent MR angiography of the main portal vein (PV) and portal vein branches after an overnight fast. Transverse two dimension time-of-flight gradient echo sequences were obtained three times, in suspended expiration and inspiration, respectively, as follows: 1) No presaturation slab, 2) presaturation slab across the SMV, 3) presaturation slab across the SV. Signal intensity (SI) measurements were obtained for all acquisitions. using regions of interest traced manually within the PV and portal branches. RESULTS: After presaturation of the SMV and SV during expiration, the overall SI average in the PV decreased by 47% +/- 8 (mean +/- SD) and 17% +/- 9, respectively. Right to left portal branch SI ratio and right-anterior to left-posterior SI ratio in the PV were 0.91 +/- 0.09 and 1.02 +/- 0.08 at baseline, respectively. They decreased significantly (P < 0.05) to 0.87 +/- 0.09 and to 0.95 +/- 0.09 after saturation of the SMV, and increased significantly to 0.95 +/- 0.08 and to 1.07 +/- 0.10 after saturation of the SV. CONCLUSION: MR angiography with selective saturation of the SMV and SV provided reproducible assessment of the respective contributions of the SMV and SV to portal flow, and allows demonstration that streamlining of splanchnic blood occurs in the portal vein of normal subjects.     

MR venography of the inferior mesentery vein

OBJECTIVE: To evaluate on three-dimensional (3D) dynamic contrast-enhanced (DCE) MR venography (MRV), the visibility of the inferior mesenteric vein (IMV), its insertion pattern into the portal system, and the difference of IMV diameters between healthy subjects and patients with cirrhosis. MATERIALS AND METHODS: Two hundred and seventeen consecutive patients who had abdominal 3D DCE MRI was included in this study. The original image data of 3D DCE MRI was used to generate multiple planar volume reconstruction (MPVR) images, which were evaluated for visualization of the IMV and its pattern of insertion into the portal system. The diameter of IMV was measured and compared in 24 patients with cirrhosis (Cirrhosis Group) and in 30 patients without hepatic lesions or liver disease (Healthy Group). RESULTS: In the 217 patients, the frequencies of visualization of IMV, grade 1 order branches and grade 2 order branches were, respectively, 88%, 24% and 9%. The IMV inserted into the splenic vein (SV), the portal confluence and the superior mesenteric vein (SMV) in 45%, 18% and 37%, respectively. Among patients with cirrhosis, 12.5% had IMV diameter larger than 5.1mm, although there was no significant difference between cirrhosis and healthy groups (P>0.05). However, the diameters of the main portal vein (MPV), SV and SMV were significantly larger in the Cirrhosis Group (P<0.05). CONCLUSION: The IMV and its branches can be depicted well by 3D DCE MRV. The most common insertion of the IMV is into the splenic vein. A minority of patients with cirrhosis had dilatation of the IMV.     

Quantification of portal venous blood flow during fasting and after a standardized meal — a MRI phase-mapping study

Portal venous blood flow was measured with a double-oblique phase-sensitive magnetic resonance imaging (MRI) flow measurement technique in six healthy volunteers after 7 h of fasting. A standard liquid meal with an energy content of 4200 kJ, containing equal parts of carbohydrate, protein and fat was given to the volunteers while in the scanner. Flow measurements were performed 5, 15 and 30 min after intake of the meal. The average portal vein blood flow was 0.88 ± 0.17 l · min^–1 during fasting. After intake of the standard meal, flow increased by 30,67 and 111% after 5, 15 and 30 min, respectively.This study shows that a non-invasive MRI technique can be used for volume flow determinations in the portal vein and that physiological changes in flow can be quantified. The technique may be of clinical value in evaluation of patients with abdominal angina as well as patients with portal hypertension. Correspondence to: C. Thomsen     

经颈静脉肝穿刺门静脉途径门静脉及肠系膜上静脉血栓溶栓治疗6例报告

目的 评价经颈静脉经肝穿刺门静脉(TIPSS)途径门静脉及肠系膜上静脉血栓溶栓治疗的安全性和治疗效果。方法 对6例诊断为门静脉(PV)和肠系膜静脉(SMV)广泛血栓形成的患者进行了经TIPSS途径介入溶栓治疗。患者主要症状有腹痛、腹胀、厌食等。腹部体检有压痛,均无明确腹肌紧张和反跳痛。经B超、增强CT检查和直接PV-SIV造影确诊为本病。溶栓方法：穿刺PV分支成功后插入导管做PV-SMV造影,确定诊断及了解栓塞范围,抽吸及捣碎血栓,间断将尿激酶经多侧孔导管注入PV和SMV清除大部分血栓后,保留多侧孔导管于SMV内持续溶栓3～13天。术后药物抗凝治疗6个月左右。此间,密切监测出凝血时间及影像学变化。结果 介入治疗后,大部分血栓被清除,PV和SMV有血流通过,腹痛、腹胀和腹泻症状逐步缓解。经留置于SMV的导管造影显示,PV和SMV主干及主要分支血流通畅,3例门静脉的肝内少数分支有残留血栓,但无明显症状。随访4个月至3年,除1例死于外科手术并发症外,其余5例患者健在,无血栓复发证据及上消化道出血发生。结论 经TIPSS途径介入溶栓治疗急性PV和SMV血栓形成是安全有效的,近期及中远期疗效均好。     

Portal Vein Stenosis Following Liver Transplantation Hemodynamically Assessed with 4D-flow MRI before and after Portal Vein Stenting

We present a case of a patient who underwent portal vein (PV) stenting for PV stenosis after a living-donor liver transplantation. A pretreatment 3D cine phase-contrast (4D-flow) MRI showed decreased, though hepatopetal, blood flow in the PV. After stenting, 4D-flow MRI confirmed an improvement in PV flow, with a more homogeneous flow distribution to each hepatic segment. 4D-flow MRI are valuable for understanding the hemodynamics of this area, planning for treatments, and evaluating the outcome of the interventions.     

Intraportal venous flow distribution: evaluation with single breath-hold ECG-triggered three-dimensional half-Fourier fast spin-echo MR imaging and a selective inversion-recovery tagging pulse.

OBJECTIVE: The purpose of this study was to evaluate the intraportal blood flow distribution from splenic and superior mesenteric veins with an unenhanced MR angiographic technique using single breath-hold ECG-triggered three-dimensional (3D) half-Fourier fast spin-echo sequence and selective inversion-recovery tagging pulse. SUBJECTS AND METHODS: Seventeen healthy volunteers were included in this prospective study. After obtaining regular single breath-hold ECG-triggered 3D half-Fourier fast spin-echo images without applying a tagging pulse, we placed the selective inversion-recovery tagging pulse on the superior mesenteric vein (TAG-A), the splenic vein (TAG-B), or on both (TAG-C) to study the inflow correlation of tagged or marked blood into the portal vein. MR images were evaluated subjectively by three reviewers. RESULTS: On MR images obtained using the TAG-A pulse to suppress the signal flow from the superior mesenteric vein into the portal vein, the most common pattern of signal loss was observed on the right half of the main portal vein (8/17 subjects). Conversely, on the MR images obtained using the TAG-B pulse, signal loss of the left half of the main portal vein was the most common pattern (11/17 subjects). Signal reduction from the splenic venous flow in the left portal vein was significantly greater than that from the superior mesenteric venous flow (p<0.05). CONCLUSION: The unenhanced MR angiographic technique using single breath-hold ECG-triggered 3D half-Fourier fast spin echo with selective inversion-recovery tagging pulse has the potential to assess the intraportal blood flow distribution from the splenic and superior mesenteric veins.     

Comparison of Ultrasound,CT, and MR Imaging in the Evaluation of Candidates for TIPS

To compare ultrasound (US), CT, and MRI in the evaluation of hepatic vascular anatomy, portal and splenic venous flow, and collateral pathways (varices and spontaneous shunts) in candidates for transjugular intrahepatic portosystemic shunting (TIPS), 17 patients with history of refractory variceal bleeding or intractable ascites underwent duplex US, contrast-enhanced CT, and MRI before TIPS. The appearance of portal and hepatic anatomy was graded from 1 (not visible) to 4 (excellent visualization) independently by four radiologists. Presence and direction of portal and splenic venous flow, and presence and location of varices and spontaneous portosystemic shunts were also assessed. Results and effects of interobserver variation were assessed for significance using Friedman's ANOVA and Wilcoxon's signed-rank test. MRI yielded higher scores than CT or US for hepatic veins (P <.0001) and inferior vena cava (P <.0001). MRI and CT scored better than US for portal vein branches (P =.012) and splenic vein (P =.0038). All tests demonstrated the main portal vein well, with no statistically significant difference. US and MRI were more sensitive than CT for detecting portal vein flow and direction (US 76%, CT 0%, MRI 82%). MRI was most sensitive for splenic vein flow and direction (US 41%, CT 0%. MRI 76%). CT and MRI were more sensitive than US in detecting varices (US 5%, CT 50%, MRI 58%) and spontaneous shunts (US 13%, CT 75%, MRI 75%). Interobserver variation did not influence results significantly P =.3691). MRI provides the most useful information and may be the preferred single imaging test prior to TIPS.     

CT测量中老年人门静脉、腹主动脉管径及其比值

目的:应用16排CT增强扫描,探讨健康中老年入门静脉与腹主动脉管径及其比值的特点.方法:取符合条件的上腹部CT增强检查的中老年人160例,按年龄分为2组(中年组40～59岁,老年组60～79岁),每组80例(其中男女各40例).测量门静脉期门静脉(PV)、腹主动脉(AA)管径,计算两者比值(R值)并进行统计学分析.结果:PV及AA直径在不同性别之间的差异具有统计学意义(P＜0.05),R值在不同性别之间的差异无统计学意义(P＞0.05).PV直径在中老年组之间差异无统计学意义(P＞0.05),AA直径及R值在中老年组之间差异具有统计学意义(P＜0.05).结论:PV、AA管径及R值的测量可以为引起门静脉或腹主动脉管径改变的相关疾病的诊断提供具有一定价值的影像学依据,R值的适用范围更广.     

Transjugular intrahepatic portocaval shunt after thrombus disruption in partially thrombosed portal veins

Portal vein (PV) thrombosis increases the risk of variceal bleeding in cirrhotic patients with portal hypertension. Its presence also complicates PV access during transjugular porto-caval shunt (TIPS) placement. We overcame this obstacle by using ultrasound (US) guidance for PV entry. Clot disruption by balloon catheters was then performed before placing the vascular endoprostheses for portal-venous shunting. We treated 3 cirrhotic patients in such fashion with good clinical results. Portal thrombi progressively disappeared after shunting due to both balloon disruption and the rise in portal blood flow velocity.     

CT criteria for venous invasion in patients with pancreatic head carcinoma

The purpose of the study was to evaluate CT criteria for venous invasion in patients with potentially resectable carcinoma of the pancreatic head, with surgical and histopathological correlation. In 113 patients evaluated with spiral CT for suspected pancreatic head carcinoma, several CT criteria for venous invasion were scored prospectively for the portal vein (PV) and the superior mesenteric vein (SMV): length of tumour contact with PV/SMV (0 mm, < 5 mm, > 5 mm); circumferential involvement of the vein (0 degree, 0-90 degrees, 90-180 degrees, > 180 degrees); degree of stenosis; irregularity of the vessel margin; and tumour convexity towards vessel. 65 patients underwent surgery. Pancreatic head carcinoma was proven and pathology of the vascular margin was obtained in 50 of these patients. CT findings for single and combined criteria were correlated with pathology in these 50 patients, 30 of whom showed venous ingrowth. Invasion was found in all cases with SMV narrowing (n = 7), PV contour involvement > 90 degrees (n = 6), PV narrowing (n = 5) and PV wall irregularity (n = 3). The vascular ingrowth rate was 88% (15/17) for tumour concavity towards the PV or SMV. Poor predictors of ingrowth were length of tumour contact with PV > 5 mm (78% ingrowth, 14/18) and contour involvement of the SMV > 90 degrees (83% ingrowth, 10/12). Absence of vascular ingrowth could not be predicted in 100%. In conclusion, CT criteria can predict a high risk of invasion in potentially resectable tumours. Narrowing of the SMV and the PV seems the most reliable criterion, as well as circumferential involvement of the PV > 90 degrees. The best combination of criteria was tumour concavity with circumferential involvement > 90 degrees (sensitivity 60% and positive predictive value 90%).     

经皮肝门脉导管药盒系统植入术

目的：研究经皮肝门脉导管药盒系统（ＰＣＳ）植入术治疗少血性肝转移癌的可行性。材料与方法：对８例不能手术的肝转移瘤患者和２例原发性肝癌肝动脉化疗栓塞术后肝动脉闭塞的患者，行经皮肝穿门脉，沿导丝送入留置管，导管留置于肠系膜上静脉或脾静脉内，药盒植入右上腹壁皮下。术后定期用５－氟尿嘧啶、阿霉素、卡铂经药盒导管系统内滴注或推注化疗。结果：所有患者门脉ＰＣＳ植入术均成功，未见手术并发症。术后随访无门脉血栓形成，２例术后留置管移位脱入腹腔。术后定期行Ｂ超或ＣＴ复查，显示５例肝转移瘤明显缩小，２例无变化，２例肿瘤增大，１例术后１２个月死亡。结论：作者认为经皮肝穿门脉导管药盒系统植入术是可行的，其创伤小、安全、操作技术简单，为少血性肝转移癌及原发型肝癌经门脉内的化疗灌注提供了一种有效的途径。     

门静脉结构异常的影像诊断及意义

本文报道了７例门静脉结构异常的影象诊断，包括门静脉海绵样变３例，门静脉重度狭窄２例，门静脉畸形１例，１例门静脉海绵样变血管结构同正常门静脉系统同时存在。检查方法包括ＵＳ、ＣＴ、ＭＲＩ和动脉法门静脉造影，ＵＳ和ＭＲＩ对门静脉结构异常的显示尚不能为ＴＩＰＳＳ治疗提供满意的信息，正确诊断率有待进一步提高，在行ＴＩＰＳＳ治疗的前，如疑有门静脉结构异常，应行间接门静脉造影，以判断ＴＩＰＳＳ治疗可行性。     

Comparison of Gadolinium-BOPTA and Ferucarbotran-enhanced three-dimensional T1-weighted dynamic liver magnetic resonance imaging in the same patient

OBJECTIVES: We sought to compare signal changes using Ferucarbotran and gadobenate dimeglumine (Gd-BOPTA) in dynamic 3D T1-weighted (T1w) GRE imaging of the liver. MATERIAL AND METHODS: Thirty patients were prospectively included in the study. All patients underwent 2 high-field magnetic resonance (MR) examinations: first with Gd-BOPTA (Gd) and then after a mean interval of 4 days with ferucarbotran (Feru). Dynamic MRI was obtained with a 3D T1w GRE sequence (TR 6.33, TE 2.31, flip angle 20 degrees ). Contrast enhanced scans were assessed before intravenous injection of the contrast agent (precontrast), and postcontrast during the arterial phase (30 seconds), portal venous phase (60 seconds), and equilibrium phase (120 seconds). The signal intensities (SIs) of liver, spleen, aorta, and portal vein were defined by region of interest measurements. Signal intensity changes (SICs) and percentage signal intensity change (PSIC) were calculated using the formulas SIC=(SI pre - SI post)/SI pre and PSIC=SIC x 100%. RESULTS: Positive signal enhancement was observed after intravenous injection of Feru during all dynamic measurements, whereas the mean SI values were lower compared with Gd. During the portal venous phase the mean SI of Gd was up to a factor of 2.1 higher (portal vein). The widest difference of SIC was observed during the equilibrium phase for liver parenchyma (Gd, 1.03; Feru, 0.24). The dynamic signal courses were similar for liver, portal vein and aorta. Different signal courses were obtained for the spleen. CONCLUSIONS: Feru-enhanced T1w dynamic images demonstrated significant signal increases for liver, vessels, and spleen but overall lower signal intensities than Gd-BOPTA. The dynamic signal courses of ferucarbotran were similar to that of Gd-BOPTA during ll perfusion phases except in the spleen. Thus, it may be possible to detect typical enhancement pattern of focal liver lesions with Feru-enhanced dynamic T1w MRI.     

Comparison of pulsed Doppler sonography and angiography in patients with portal hypertension

Pulsed Doppler sonography and liver panangiography were performed in 43 patients with cirrhosis. Fourteen patients were evaluated preoperatively, and 28 patients were evaluated after a variceal decompressive shunt. One patient was studied before and after undergoing a shunt. The direction of portal blood flow by Doppler sonography was compared with both the grading pattern and direction of flow by angiography. When portal blood flow was determined to be antegrade by Doppler sonography, angiography showed antegrade flow in 84% (grade I, II, or III portal venous pattern). Six percent had retrograde flow (grade IV), and 10% had portal vein thrombosis. When the portal blood flow was determined to be retrograde by Doppler sonography, angiography showed retrograde flow (grade IV portal venous pattern) in 80% and antegrade flow (grade I, II, or III) in 20%. When an inadequate Doppler tracing was obtained from the portal vein, angiography showed either grade I, II, or III in 38%; grade IV in 50%, and portal vein thrombosis in 13%. There was poor correlation between the calculated mean flow rates, as determined by Doppler sonography, and the angiographic grade. We conclude that pulsed Doppler sonography is accurate in determining the direction of portal flow when an adequate tracing is obtained (36 of 44 studies). When an inadequate tracing is obtained, retrograde portal flow or portal vein thrombosis is likely.     

肝细胞急性坏死与凋亡的磁共振扩散加权成像活体检测实验研究

 目的 评价MRI、DWI检测及鉴别肝细胞凋亡和坏死两种病理改变的价值.方法 72只S-D大鼠随机分成假手术对照组、右侧肝动脉与门静脉分支均结扎组(HA+PV组)和单独右侧门静脉分支结扎组(PV组),各24只.每组再分成4个亚组,每个亚组6只,分别于术后3 h、12 h、24 h、72 h行MRI、DWI检查,检查结束后取肝标本作HE染色、TUNEL染色,将病理结果与影像检查进行对照分析.结果 右侧门静脉与肝动脉均结扎后,肝右叶于术后3 h在T2WI上即表现为高信号,ADC值下降.单独肝右侧门静脉结扎后12 h,肝右叶ADC值出现升高,至24 h肝细胞凋亡数达最高,ADC值也达最高.结论 T2WI和DWI可早期检测发生坏死的肝组织.而组织中细胞发生凋亡后,DWI较T1WI、T2WI早期检测到凋亡组织.     

Noncontrast SSFP pulmonary vein magnetic resonance angiography: impact of off-resonance and flow

Purpose

To investigate pulmonary vein (PV) off‐resonance and blood flow as causes of signal void artifacts in noncontrast steady‐state‐free‐precession (SSFP) PV magnetic resonance angiography (MRA).

Materials and Methods

PV blood off‐resonance was measured on 11 healthy adult subjects and 10 atrial fibrillation (AF) patients. Noncontrast PV MRA was performed using a 3D slab‐selective SSFP sequence at 1.5T on seven healthy subjects with signal profile shifts of 0–125 Hz. The time‐resolved blood flow velocity of the PVs was measured on five healthy subjects. The impact of flow was studied on six healthy subjects, on whom SSFP PV MRA was acquired twice with the electrocardiogram (ECG) trigger delay corresponding to low and high flow, respectively.

Results

The PV off‐resonances were 97 ± 27 Hz, 65 ± 20 Hz, 74 ± 25 Hz, and 52 ± 17 Hz for right inferior, left inferior, right superior, and left superior PVs, respectively, on healthy subjects, and 74 ± 20 Hz, 38 ± 9 Hz, 51 ± 20 Hz, and 28 ± 11 Hz on AF patients (P<0.01 for all). The off‐resonance caused severe signal voids in the PVs. Signal acquired during mid‐diastole with high PV flow caused additional signal voids in the left atrium, which was reduced by setting the ECG trigger delay to late‐diastole.

Conclusion

PV off‐resonance and flow causes signal void artifacts in noncontrast 3D slab‐selective SSFP PV MRA. J. Magn. Reson. Imaging 2010;32:1255–1261. © 2010 Wiley‐Liss, Inc.     

Evaluation of MR/fluoroscopy-guided portosystemic shunt creation in a swine model

PURPOSE: To evaluate three different percutaneous portosystemic shunts created with magnetic resonance (MR) imaging and fluoroscopy guidance in a swine model. MATERIALS AND METHODS: In stage 1 of the experiment, an active MR intravascular needle system was created for needle tracking and extracaval punctures. Twenty inferior vena cava (IVC)/superior mesenteric vein (SMV)/portal vein (PV) punctures were performed in 10 swine (weight, 40-45 kg) in a 1.5-T short-bore interventional MR imager. With use of a real-time MR imaging sequence, the needle was guided through the IVC and into the SMV or PV (N = 20 punctures). After confirmation, a wire was advanced into the portal venous system under MR imaging guidance (N = 20). In stage 2, animals were transferred to the radiographic fluoroscopy suite for deployment of shunts. Three different shunts were evaluated in this study: (i) a commercial stent-graft, (ii) a prototype bridging stent, and (iii) a prototype nitinol vascular anastomotic device. Postprocedural necropsy was performed in all animals. RESULTS: Successful MR-guided IVC/SMV punctures were performed in all 20 procedures (100%). All three shunts were deployed. Stent-grafts had the poorest mechanism for securing a shunt. The vascular anastomotic device and the bridging stent had more secure anchoring mechanisms but also had higher technical failure rates (50% and 40%, respectively). When deployed successfully, the vascular anastomotic device resulted in no bleeding at the sites of punctures at necropsy. CONCLUSION: Percutaneous shunts and vascular anastomoses between the portal mesenteric venous system and IVC were successfully created with use of a combination of MR imaging and conventional fluoroscopy for guidance.     

Quantitative assessment of portal vein flow in subjects with active chronic hepatitis: comparison of magnetic resonance angiography with bolus tracking with color Doppler ultrasonography]

PURPOSE: To assess the accuracy of time-of-flight MR Angiography (MRA) with bolus tracking in evaluating mean blood velocity and flowrate in the portal vein in patients with chronic hepatitis versus healthy volunteers. MATERIAL AND METHODS: Fifteen patients with clinically-defined post-viral chronic hepatitis (viruses B and C) were examined with bolus tracking MRA and color Doppler US to evaluate portal blood flow. Both examinations were performed before and after a 1500 kcal meal. We evaluated mean blood flow velocity and flowrate in the portal vein. MRA results were compared with color Doppler findings; the results in chronic hepatitis patients were compared with those of healthy volunteers. RESULTS: The correlation between mean portal blood velocity, as measured with MRA and color Doppler US, was r = .82 before and r = .79 after the meal. There was no significant difference in mean velocity between the chronic hepatitis patients and the healthy volunteers. The correlation between portal flowrate, as measured with MRA and color Doppler US, was r = .87 before and r = .91 after the meal. There was no significant difference in mean flowrate between the chronic hepatitis patients and the healthy volunteers. In contrast, there were significant differences in mean velocity and portal flowrate, as measured with MRA before the meal, between the chronic hepatitis patients and the healthy volunteers. DISCUSSION AND CONCLUSIONS: Bolus tracking MRA is superior to color Doppler US in quantitating blood flow in the portal vein and evaluating changes after a meal. Decreased mean velocity and flowrate may indicate impaired function, as it happens in early chronic hepatitis.     

螺旋CT多期扫描在肠系膜上静脉梗塞中的诊断价值

目的 探讨螺旋CT多期扫描在SMV梗塞中的诊断价值. 资料与方法 7例SMV梗塞患者,行CT平扫、门静脉期增强扫描及延迟扫描,分析其CT表现特点,并与超声及手术后病理结果对照. 结果 临床病理证实的SMV主干梗塞患者CT平扫均表现肝脏呈等密度,肠系膜充血水肿.增强扫描显示SMV内圆形充盈缺损,肠管扩张、肠壁增厚、靶征、肠壁强化程度减低等肠缺血表现.门静脉供血减少,门静脉期延迟,肝脏一过性血供不足.延时扫描对比剂在肝脏内分布均匀. 结论 螺旋CT多期扫描在SMV梗塞诊断中具有重要价值.