CT灌注成像及其临床应用

人的正常生理性功能活动以及各种病理性活动与人体内血流变化密切相关,因此获取人类活体组织微循环血流的灌注信息一直是医学影像学关注的热点。传统的测定活体组织灌注一直为核医学的研究领域,包括正电子发射体层摄影、氙-CT以及单光子发射体层摄影等。近年来,随着磁共振平面回波技术以及螺旋CT和多层CT扫描技术的发展,灌注成像技术得以应用于临床。CT灌注成像与MR灌注成像比较,主要临床优势在于相对简单易行,且适于急诊检查,因此有其更为广阔的发展空间。90年代初Miles等犤1犦提出了CT灌注成像的概念,即在静脉团注对比剂后行同层快…     

灌注成像与CT发展在脑肿瘤中的应用

CT灌注成像技术中各种灌注参数本质上反映了脑肿瘤的血流动力学特点与肿瘤内部微血管密度的情况，不同组织学类型的脑肿瘤，其病理生理及血流动力学改变也不尽相同。研究不同性质不同级别脑肿瘤的绝对灌注参数之间的差异及与肿瘤的相关性，对脑肿瘤的定性诊断与鉴别诊断有重要意义。本文重点介绍灌注成像的发展、各种灌注成像技术在脑部应用的比较与CT灌注成像优势。     

CT灌注成像对门脉高压分流术后肝血流灌注改变的评价

目的应用多层螺旋CT观察肝硬变门脉高压患者门腔静脉分流后肝脏血流灌注的改变。方法肝硬变门静脉高压合并上消化道出血患者15例。肝功能Child分级A级13例、B级2例。在分流术的前后两周之内各进行一次CT血流灌注扫描。测量每一例患者的肝血流量(HBF)、肝血容量(HBV)、平均通过时间(MTT)、毛细血管通透性(PS)和肝动脉灌注指数(HPI)。所测参数与术中测量的分流前后门静脉压力作对照观察。结果门腔静脉分流前/后的各灌注参数为:HBF120.0/110.1ml/(min·100ml)(P>0.05)、HBV17.9/20.9ml/100ml(P>0.05)、MTT13.6/14.2s(P>0.05)、PS35.8/37.5ml/(min·100ml)(P>0.05)、HPI0.21/0.42(P<0.01)。门腔静脉分流前/后的门静脉压力为41.7/28.1cm水柱(P<0.001)。结论肝脏CT灌注成像显示肝硬变门脉高压患者的肝血流量下降,肝动脉指数在分流术后明显增高,提示门静脉灌注量降低。CT血流灌注扫描助于了解肝硬变门脉高压的血流动力学改变。     

全氟显心肌灌注显像的方法学和临床应用研究

目的探讨全氟显实时心肌灌注显像的方法学和临床应用的可行性.方法在50例患者中,经外周静脉弹丸式注射全氟显,应用实时心肌灌注显像技术,记录心尖四腔观6个心肌节段的心肌显影效果,并监测患者造影前后的心电图、呼吸、心率和血压变化.结果50例患者左室壁心肌组织均获得了满意的显影效果,造影前后的心电图、呼吸、心率和血压无明显变化.结论临床经外周静脉弹丸式注射全氟显行实时心肌灌注显像取得了满意的效果,临床应用是可行的.     

门静脉阻断兔肝VX2移植瘤的CT灌注评价

目的探讨CT灌注成像评价门静脉阻断兔肝VX2移植瘤后血流变化的价值。方法40只新西兰大白兔随机分为门静脉阻断后即刻移植瘤体组(A组)、移植瘤体生长3周后门静脉阻断组(B组)、阴性对照组(C组)、移植瘤体未行门静脉阻断的阳性对照组(D组)各10只。经CT灌注扫描后应用去卷积模式自动计算出肝血流量(BF)、血容量(BV)、平均通过时间(MTT)、血管表面通透性(PS)和肝动脉灌注分数(HAF)等CT灌注参数。结果实验A组BF、BV、MTT和PS值均较对照C组低,BF值:(1.40±0.70)ml/(100 g.min)比(133.21±14.42)ml/(100 g.min)(P<0.01);BV值:(0.33±0.17)ml/100 g比(28.77±3.32)ml/100 g(P<0.01);MTT值:(4.33±1.41)s比(11.67±0.58)s(P<0.01);PS值:(0.15±0.18)ml/(100 g.min)比(22.10±4.39)ml/(100 g.min)(P<0.01)。但实验A组的HAF值较对照C组明显增高:(0.99±0.03)比(0.25±0.06)(P<0.01)。实验B组的BF、BV、MTT和PS值较对照D组降低,而HAF值则明显增高(P<0.01)。结论CT灌注成像可无创直观形象地评价门静脉阻断后兔肝VX2移植瘤的灌注特点。     

DECT首过心肌灌注成像的临床应用

目的 探讨双源CT(DECT)心肌灌注成像的临床应用价值.方法 选取59例接受DECT心肌灌注成像及SPECT负荷心肌显像者,根据检查结果分为A组(对照组,20例)和B组(缺血性心脏病组,39例),测量A组各心肌节段以及B组灌注缺损区、缺损周边及缺损对侧心肌CT灌注值(VNC及Overlay值).比较DECT与SPECT检出早期心肌灌注缺损(EPD)的差异,分析冠状动脉狭窄程度对两种检查方法一致性的影响.结果 A组心尖部、中间部及基底部VNC、Overlay值的差异无统计学意义(P均＞0.05).B组中DECT检出92处EPD,其中53处经SPECT证实,二者检查结果的差异无统计学意义(x2 =3.403,P=0.065),呈中等相关(r=0.533,P＜0.01).供血冠脉轻度狭窄时两种检查方法检出EDP的差异有统计学意义(x2=11.396,P＜0.01),而中度及重度狭窄时两种检查方法检出EDP的差异无统计学意义(P均＞0.05).结论 DECT首过心肌灌注成像能准确评估正常心肌及缺血心肌的灌注情况,与SPECT检查结果具有相关性,且更易检出早期、轻度心肌缺血.     

Cost analysis: concepts and application

Public health nurses are increasingly called upon to justify the cost of care or to decide which of two alternative programs is more cost-effective. Cost studies can be complex and difficult to conduct, but an understanding of the basic techniques allows nurses to fully participate in planning, implementing, and evaluating programs that greatly impact the health of the community. This article defines some of the basic terms used in health economics, discusses standard methods of cost analysis, and provides an example of neonatal screening to illustrate methods of describing, measuring, and assigning a value to cost items.     

CT灌注成像及其在中枢神经系统的临床应用

20世纪80年代初,Axel等[1]提出了CT灌注成像(PI)的理论设想,快速螺旋CT扫描技术的发展,使这一理论成为现实。近年,随着多层螺旋CT的应用,CTPI在评价组织器官灌注状态上的重要作用引起人们的普遍关注,尤其在中枢神经系统的应用格外引人注目。现就CT灌注技术的基本原理及其中枢神     

Hepatic arterial perfusion scintigraphy.

Nurses caring for patients with liver cancer may be asked to help administer radiopharmaceuticals and to measure the effectiveness of such treatments. With the right knowledge, they can also help alleviate patient fears.     

彩色灌注图法在肝脏螺旋CT灌注成像中的临床应用

随着CT机软硬件技术的进步,以反映组织、器官血流动力学变化为目的的CT灌注成像成为当前的研究热点。CT灌注成像在脑部的应用已基本成熟[1-2],在肝脏等体部实质器官也已由实验研究逐渐转向临床应用[3-6]。以往获得肝脏CT灌     

Hepatic porphyrias. Current concepts.

Acute intermittent porphyria, variegate porphyria, and hereditary coproporphyria are hepatic porphyrias due to enzyme defects that are inherited as autosomal dominants. Porphyria cutanea tarda is considered an acquired disorder. Similar drugs or circumstances are precipitants of acute attacks in all three inherited hepatic porphyrias. The respective biochemical abnormalities are identifiable by simple, readily available laboratory tests. Management of patients with any of the inherited hepatic porphyrias is directed primarily toward prevention of attacks through avoidance of precipitants and through a diet high in carbohydrate. Therapy for porphyria cutanea tarda includes interdiction of alcohol use and repeated phlebotomy.     

Mucinous rectal cancer: concepts and imaging challenges

Abdominal Radiology - Rectal adenocarcinoma with mucinous components is an uncommon type of rectal cancer with two distinct histologic subtypes: mucinous adenocarcinoma and signet-ring cell...     

Hepatic and splenic sarcoidosis: Ultrasound and MR imaging

Abdominal imaging studies may be performed for various indications in patients known to have sarcoidosis. To assess magnetic resonance imaging (MRI) and sonographic ability to detect abnormalities in sarcoidosis patients with abdominal involvement, a prospective study on 18 selected patients was performed. Besides organomegaly, when present, ultrasound demonstrated normal or increased hepatic parenchymal echogenicity, coarsening of the liver parenchyma with or without discrete nodules, focal calcifications, as well as contour irregularity. Splenic discrete nodules were seen on ultrasound in a single patient. Besides organomegaly, MRI abnormalities include abnormal hepatic signal intensity, discrete nodules, contour irregularity, spiculation of small hepatic vascular branches, and a high periportal signal intensity. MRI splenic abnormalities include contour irregularity, nodularity, and abnormal signal intensity.The data presented in this study reveals the spectrum of ultrasound and MRI findings in sarcoidosis patients with abdominal organ involvement, potentially enabling the evaluation of the severity of the disease. MRI appears more sensitive than ultrasound for study of abdominal sarcoidosis.     

Hepatic epithelioid hemangioendothelioma: MR imaging findings

We report the MRI findings in three patients with pathologically proven hepatic epithelioid hemangioendothelioma, a rare tumor of the liver that is not well described in the MR imaging literature. The recognition of the imaging features of this rare malignancy may help further early detection and surgical treatment of this potentially curable disease.     

Hepatic adenomatosis: spectrum of imaging findings

Objective

This pictorial essay reviews the imaging appearance and differential diagnosis of hepatic adenomatosis.

Conclusion

In addition to such entities as multifocal hepatocellular carcinoma, metastases, and multiple focal nodular hyperplasia, hepatic adenomatosis should also be considered when confronted with multiple hypervascular liver lesions. Certain CT and MRI features can strongly suggest the diagnosis of adenomatosis.     

急性脑静脉闭塞DWI、PWI 与CTPI 对比的实验研究

目的对比磁共振扩散加权成像(DWI)、灌注加权成像(PWI)和CT灌注成像(CTPI)评价急性脑静脉闭塞模型的价值。方法家猫18只,随机分为6小组,术后1、3、6、12、24、48h各3只。采用开颅上矢状窦穿刺注射液体栓塞剂——醋酸纤维素聚合物(CAP)制备急性脑静脉闭塞动物模型,对各组模型行DWI、PWI和CTPI检查,对比MR、CT对病灶检出率、脑实质损害容积及程度判断的一致性。结果DWI发现10只猫脑实质出现19个异常信号,PWI发现13只猫脑实质内23个异常灌注区,CTPI发现12只猫脑实质内20个异常血流灌注区。PWI平均通过时间(MTT)参数图与CTPI局部脑血流量(rCBF)参数图对病灶容积的测量差异无统计学意义(t=1.54,P>0.05)。PWI和CTPI局部脑血容量(rCBV)图对脑实质损害程度判断一致性好(Kappa=0.69,P<0.01)。结论DWI、PWI与CTPI对急性脑静脉闭塞脑实质损害的判断均能提供重要信息,具有较好的一致性。     

Hepatic segmental atrophy and nodular elastosis: imaging features

Purpose

To evaluate the imaging features of hepatic segmental atrophy and nodular elastosis.

Materials and methods

In this Institutional review board (IRB)-approved, HIPAA-compliant study, we reviewed imaging features in six cases of histologically confirmed hepatic segmental atrophy (HSA) and nodular elastosis (NE). Retrospective review of ultrasound (US) in 2 patients, computed tomography (CT) in 5 patients, magnetic resonance imaging (MRI) in 4 patients, and positron emission tomography (PET) in 2 patients was performed. Location, size, and attenuation/density/signal intensity of these lesions were evaluated. Clinical presentation and coexistent conditions were also recorded.

Results

All six patients were females. Mean age of presentation was 58.3 years (range 37–80). A single HSA and NE lesion in each patient was found. The mean size of the lesion was 18 mm (range: 3 mm to 36 mm). Most lesions were detected incidentally (5/6). On contrast-enhanced single-phase (portal venous) CT, most lesions were hypodense (4/5) and one lesion was hyperdense to fatty liver parenchyma. On MRI, the lesions were iso- to hyperintense on T2-weighted images, T1 hypointense, and hyperintense on diffusion-weighted images (DWI). Three lesions were hypointense on arterial, portal venous, and delayed phases. One lesion occurring in fatty liver appeared hyperintense on all three phases. Gd-EOB-DTPA-enhanced images were available in 2 patients and lesions were hypointense on the 20-min hepatobiliary phase. On PET, two lesions were isometabolic to the background hepatic parenchyma. On ultrasound, one lesion appeared hypoechoic and another lesion isoechoic to hepatic parenchyma.

Conclusions

Hepatic segmental atrophy and nodular elastosis is an uncommon benign lesion and can simulate metastases due to variable imaging features. Lack of FDG uptake on PET/CT may be a clue to the benign nature of the lesion and may suggest the possibility of HSA and NE.

     

Hepatic perfusion abnormalities in acute pancreatitis: CT appearance and clinical importance

BACKGROUND: The purpose of the present study was to describe the computed tomography (CT) appearances of transient hepatic attenuation differences (THADs) in patients with acute pancreatitis and to discuss the mechanism of THAD. METHODS: Two-phase dynamic CT images of 28 patients with acute pancreatitis were reviewed. Among them, THAD was seen in nine patients. All patients underwent ultrasonography, and four patients with THAD underwent surgery. RESULTS: Three types of THAD (THAD adjacent to the gallbladder in five of 28 patients, THAD with left lobar distribution in three of 28, wedge-shaped THAD in one of 28) were seen on the two-phase dynamic CT scans of patients with acute pancreatitis. In five patients, THAD disappeared when acute pancreatitis had subsided. CONCLUSIONS: THAD in acute pancreatitis is probably caused by increased arterial blood flow attributable to the inflamed lobe of the liver or the inflamed gallbladder. THAD in acute pancreatitis should not be confused with primary liver abnormalities.