（推薦精選）CT灌注成像

1、 反映組織的血管化程度及血流灌注情況，獲得血液動(dòng)力學(xué)方面的信息。 方法：快速造影劑團(tuán)注后(5ml/s以上)，在首次經(jīng)過(guò)受檢組織的過(guò)程中對(duì)某一選定的層面進(jìn)行快速動(dòng)態(tài)掃描，獲得一系列動(dòng)態(tài)圖像，分析造影劑通過(guò)每個(gè)像素所對(duì)應(yīng)的體素密度的差異，從而得到反映血流灌注情況的參數(shù)。CT灌注成像 (Perfusion)1 腦梗塞 肝、腎血流灌注及腫瘤的診斷 腎移植的血流灌注的評(píng)價(jià)，了解移植血管的情況電子束CT的灌注可了解心臟灌注，有助于缺血性心肌病的早期診斷CT Perfusion應(yīng)用2 由腦局部缺血而阻礙血液擴(kuò)散是導(dǎo)致中風(fēng)，占腦中風(fēng)70%。用血纖維蛋白可溶解閉塞的血管。 發(fā)生中風(fēng)后，有效治療的時(shí)間為3小時(shí)左右

2、。要盡快了解病情類(lèi)型、發(fā)病時(shí)間和局部缺血的程度。 在這段時(shí)間內(nèi)常規(guī)CT檢查較難發(fā)現(xiàn)，而灌注CT可應(yīng)用于急性中風(fēng)檢查。CT 灌注3 前動(dòng)脈供血區(qū)中動(dòng)脈供血區(qū)后動(dòng)脈供血區(qū)外則內(nèi)側(cè)底面腦動(dòng)脈系統(tǒng)4 腦動(dòng)脈系統(tǒng)5 在快速注射造影劑后，計(jì)算和腦的擴(kuò)散有關(guān)的參數(shù)，從不同側(cè)面提供中風(fēng)的灌注分布情況： 腦血液流量Cerebral Blood Flow, CBF 腦血液容量Cerebral Blood Volume, CBV 造影劑達(dá)到各點(diǎn)最大值的時(shí)間Time Peak，TP 平均通過(guò)時(shí)間Mean transit time，MTT通過(guò) CBV 與 MTT 可獲得 CBFCT Perfusion6 常規(guī)CT通過(guò)組

3、織對(duì)X線(xiàn)不同衰減來(lái)顯示圖像 CTA通過(guò)造影劑在血管內(nèi)流動(dòng)來(lái)顯示血管結(jié)構(gòu) 灌注CT利用血液流動(dòng)有關(guān)的參數(shù)CBF信號(hào)強(qiáng)示流速大；造影劑到達(dá)高峰的時(shí)間分布圖TP，愈大意味著造影到達(dá)晚。 CBF直接把它和向腦組織提供氧的總量聯(lián)系起來(lái)，同時(shí)也與血液動(dòng)力學(xué)方面有關(guān)。CT Perfusion7 紫色區(qū)域?yàn)檠髁可?大腦急性中風(fēng)區(qū)域紅色區(qū)域血流量大CBF8 71歲婦女在癥狀開(kāi)始90分鐘后進(jìn)行檢查。CT平掃示無(wú)反常情況，但CBF示腦左側(cè)(中腦和左半動(dòng)脈供血)大部分，(前腦動(dòng)脈)提供地區(qū)嚴(yán)重局部缺血，示頭顱內(nèi)頸動(dòng)脈的雙枝閉塞。CT Perfusion9 左半腦癥狀出現(xiàn)60分鐘后，CT平掃無(wú)腦異常血液流動(dòng)，(b)示

4、左側(cè)半腦廣泛性和右前部的局部缺血。原因：左頸內(nèi)動(dòng)脈閉塞。10 CBF CBV Time-to-peak image男44歲右腦中風(fēng)約2小時(shí)，CBF在腦島的腦皮層和豆?fàn)詈撕蟛浚緡?yán)重?cái)U(kuò)散障礙(接近零)。與左邊半球比較，中腦動(dòng)脈血液供應(yīng)相當(dāng)少。CBV顯示同樣情況，但在右側(cè)MCA其他地方血液容量接近正常。與左邊區(qū)域比較，達(dá)到頂點(diǎn)時(shí)間圖在延長(zhǎng)(造影劑延遲到達(dá))。MCA MI段栓塞和小腦膜血液供應(yīng)良好，11 CBF Time-to-peak image 3天后 CT上述病例進(jìn)行動(dòng)脈血纖維蛋白溶解處理，治療后一天，用擴(kuò)散CT成像顯示了治療效果，3天以后CT平掃，示梗塞形成，核心區(qū)域與CBF和CBV圖像相似

5、。12 在梗塞核心區(qū)域范圍確定方面，CT灌注能提供重要信息，可繪局部缺血輪廓，用高密度來(lái)顯示。 用于辨認(rèn)梗塞灶核心和周?chē)Ｈ植咳毖?陰影)，為外科提供治療方法。 通常CBV的梗塞灶小于CBF和TP，MRI也如此，一般認(rèn)為CBV提供的信息較正確。早期CBV減少 與隨后梗塞形成程度較接近。CT Perfusion應(yīng)用13 與CBV(b)相比CBF (a)、TP(c)在MCA中局部缺血間不匹配。 在腦島腦皮層背部(箭)有一梗塞灶。再通治療法后24小時(shí)(d)在MCA同樣位置示受限梗塞區(qū)。14 71-year-old female patient with right-sided hemiplegia

6、(偏癱) and global aphasia(失語(yǔ)). Plain CT (90 minutes later) reveals no early signs of an ischemia(局部缺血).The parameter images display the entire extent of the ischemia with a high-grade reduction of CBF and CBV, a lacking detection of the contrast bolus in the time-to-peak image. The infarction(梗塞) incl

7、udes the region of the anterior cerebral artery and large portions of the region supplied by the middle cerebral artery, both features indicative of an occlusion of the intracranial carotid bifurcation.Case 115 16 Patient (male 44) with a right-sided ischemia in the region of the middle cerebral art

8、ery (MCA) which began 160 minutes ago. Typical findings of a high-grade disturbance in perfusion in the insular cortex and the posterior portion of the lentiform nucleus with a reduction in CBF and CBV as a result of an embolic occlusion in the distal M1 segment.The other regions supplied by the MCA

9、 demonstrated good leptomeningeal collateral blood supply which only showed moderately reduced CBF and CBV values, as well as a prolongation of the time-to-peak.Case 217 In the calculation of relative perfusion indices from CBF values in ischemic areas and in mirrorred ROIs within the unaffected hem

10、isphere proved to be a valuable method for the prognostic evaluation of a region with reduced perfusion.The core of the infarct and the ischemic marginal zones demonstrate clearly different CBF perfusion indices (green-marked ROI = 0.17 versus red-marked ROI = 0.69 ). 18 The findings of perfusion CT

11、 could be verified by DSA with regard to the type of occlusion and the condition of the collateral blood supply . The follow-up CT after a successful intra-arterial fibrinolysis shows the infarct in dimensions comparable to the infarct core seen with perfusion CT.19 70 minutes after the occurrence o

12、f the infarction, the CBF image revealed a highgrade ischemia in the frontal region of the supply area of the MCA and in the lentiform nucleus (Fig. 3a) with a perfusion index in the greenmarked ROI of 0.07 (Fig. 3b). As a result of the good collateral flow, the disturbance in perfusion in the remai

13、ning region of the MCA, with a perfusion index of 0.82, is not seen to be very extensive (red-marked ROI in Fig. 3b). 36-year-old male patient with an embolic occlusion in the M1 segment of the left MCA and a simultaneous occlusion of the left internal carotid artery as a result of dissection. Case

14、320 Because of the partially high-grade ischemia on the one hand and the excellent collateral blood supply of the marginal region on the other, fibrinolysis was not performed in spite of the short time interval. As expected, the follow-up CT revealed the development of an infarction in the area whic

15、h had primarily demonstrated a high-grade ischemia.21 灌注CT與顱腦CT掃描和顱腦CT血管造影術(shù)結(jié)合為腦梗塞早期檢查提供了一種有用工具。 常規(guī)CT可檢查梗塞區(qū)域的形成 灌注CT可決定局部缺血的區(qū)域，提供了局部缺血組織的位置和潛在病變區(qū)域 CT血管造影術(shù)為診斷提供了相應(yīng)病灶區(qū)域的形態(tài)。為臨床工作人員決定進(jìn)一步治療的方案提供了重要信息。22 CT Perfusion前景 目前認(rèn)為中風(fēng)處理的最佳時(shí)間在60分鐘。通過(guò)對(duì)造影劑注入位置與方式的研究，灌注CT在不到15分鐘中完成中風(fēng)評(píng)價(jià)過(guò)程。23 In the course of an investig

16、ation performed on 33 patients, an attempt was made to carry out a quantitative evaluation of the severity of the ischemia with the aid of an ROI-evaluation of the CBF images. the calculation of relative perfusion indices from CBF values in ischemic areas and in mirrorred ROIs within the unaffected

17、hemisphere proved to be a valuable method for the prognostic evaluation of a region with reduced perfusion.24 Ischemias with a mild to moderate degree of severity (CBF perfusion index: 0.35- 0.9) progressed well under fibrinolytic therapy.Even in ischemic regions with a CBF index of 0.35, intra-arte

18、rial fibrinolysis could prevent the development of an infarct in more than half of the cases, as long as the index did not fall below a critical value of 0.2. Otherwise, as could be verified with follow-up investigations carried out with computed tomography and magnetic resonance tomography, ischemic necroses were seen to develop without excepti