Correspondence of CT perfusion imaging to pathological manifestations in rabbit models of hyperacute cerebral infarction

BACKGROUND: Could the infarction be diagnosed quickly and accurately at the acute stage by CT perfusion imaging (CTPI) technology? Whether the images of CTPI will correspond with the pathological changes or not? All the questions need to be solved by experimental and clinical studies. OBJECTIVE: To reveal the rules of perfusion map changes and guide the early diagnosis of hyperacute cerebral infarction by analyzing the correlation of CTPI with pathological manifestations for hyperacute cerebral infarction. DESIGN: A randomized controlled animal experiment. SETTING: Experimental Center of Medical Radiology, Longgang Central Hospital of Shenzhen City. MATERIALS: Forty-two adult New Zealand rabbits of (2.6±0.5) kg, either male or female, were randomly divided into experimental group (n =36) and control group (n =6). Six rabbits in the experimental group were observed after ischemia for 0.5, 1, 2, 3, 4 and 6 hours respectively, and 1 rabbit in the control group was observed at each corresponding time point. METHODS: The experiments were carried out in the Experimental Center of Medical Radiology, Longgang Central Hospital of Shenzhen City from March 2003 to July 2004. Rabbit models of cerebral infarction were established by modified O'Brein method. ① The rabbits in the experimental group were scanned at 0.5, 1, 2, 3, 4 and 6 hours after ischemia respectively. The dynamic CT scan slice was 13 mm from the anterior edge of the frontal cortex, and six fake color functional images were obtained, including cerebral blood flow map (CBF map), cerebral blood volume map (CBV map), peak to enhancement map (PE map), flow without vessels map, time to peak map (TP map), time to start map (TS map). The manifestations and changes of the functional maps in different interval were observed. ② Bilateral symmetric ranges of interest (ROI) were drawn separately on the CBF map, CBV map, TP map and TS map. The blood flow parameters of focal and contralateral cerebral tissues could be obtained to calculate relative cerebral blood flow (rCBF, rCBF=focal CBF/contralateral CBF), relative cerebral blood volume (rCBV, rCBV= focal CBV/ contralateral CBV), a relative time to peak (rTP, rTP= focal TP–contralateral TP), a relative time to start (rTS, rTS= focal TP–contralateral TP). ③ The perfusion maps were input into AutoCAD software. The percents of ischemic cores and peri-ischemic areas accounting for contralateral cerebral hemisphere were calculated. ④ The animals were anesthetized and killed, then the cerebellum and low brain stem were taken out. The brain tissues were cut on coronal plane at 14 mm from the anterior edge of the frontal cortex, a 2-mm piece anterior to the incision, and a 3-mm piece posterior to the incision. The anterior piece was fixed, stained and observed. A 1-mm slice was cut from the front of the posterior piece tissues as electron microscope sample, the remnant was fixed and then taken out, and the location and size of stained "white" areas were observed as the reference for electron microscope sample. ⑤ The correlation between CTPI and pathological manifestations was observed. MAIN OUTCOME MEASURES: ① Laws of time and spatial changes of ischemic areas; ② Pathological changes of the ischemic tissues; ③ Correspondency between CTPI and pathological manifestations. RESULTS: ① Laws of time and spatial changes of ischemic areas: Relative ischemic-core areas were consistent in each perfusion map, increased incessantly along with the ischemic times. Relative peri-ischemic areas were inconsistent in each perfusion map, on CBF map from 1 to 6 hours after ischemia, the area of ischemic core increased from (1.503±0.523)% to (7.125±1.054)%, the ascending trend occurred. But the peri-ischemic areas showed a descending trend on CBF map, the areas decreased from (8.960±0.719)% to (5.445±0.884)% from 0.5 to 6 hours; The relative areas were the largest one on TP maps, the average value was (32.796±3.029)% at 0.5 hour after ischemia happening (60.540±1.683)% at 6 hours. The trend of ischemic areas was increased. No obvious change was observed on TS maps. ② Pathological changes of the ischemic tissues: Under light microscope, there was no obvious change at 0.5–2 hours after ischemia, edema at 3 hours, karyopycnosis at 4 hours and eosinophilous changes at 6 hours; Under electron microscope, there was edema in ischemic cores within 4 hours after ischemia, whereas karyopycnosis or structure vanished after 4 hours; Edema was observed in peri-ischemic areas. ③ Correlation between CTPI and pathological manifestations: On CTPI maps, the ischemic core was blue on CBF and CBV maps, black on TP and TS maps. Along with the ischemic times, the rCBF and rCBV decreased, whereas the rTP and rTS prolonged. Hemodynamic parameters were not significantly different within 2 hours of ischemia and 2 hours after ischemia. The rTP and rTS became 0 after 1 and 2 hours respectively. On CTPI maps the peri-ischemic area was red on CBF and CBV maps, red and yellow on TS maps, red on TP maps. Along with the ischemic times, the rCBF decreased, and the lowest level was always at about 20%, whereas the rTP and rTS prolonged. CONCLUSION: ① CTPI manifestations corresponded well with pathological findings, and it is a sensitive, stable and reliable technique to diagnose hyperacute cerebral infarction. ② TP map was more sensitive than CBF map and TS map in exhibiting the peri-ischemic areas, thus TP maps could be a good choice for observing peri-ischemic areas.     

64排动态CT脑灌注成像在脑梗死缺血半暗带中的临床应用

目的应用64排动态CT脑灌注成像技术探讨脑梗死缺血半暗带情况。方法观察测量43例存在缺血半暗带脑梗死患者的梗死核心区、缺血半暗带区及其镜像对侧各灌注参数值。结果 43例缺血半暗带区表现为平均通过时间(MTT)、达峰时间(TTP)均延长,脑血流量(CBF)下降,而脑血容量(CBV)表现为轻度升高、正常或轻度降低。缺血半暗带区与梗死核心区比较,CBV、CBF、MTT及TTP值差异均有统计学意义(P<0.05)。缺血半暗带与健侧对应区比较,CBF、MTT、TTP值差异有统计学意义,CBV差异无统计学意义。结论应用64排动态CT脑灌注成像,对脑梗死患者可明确病变部位、范围以及有无缺血半暗带的存在。     

颈动脉钙化与缺血性卒中：回顾性病例系列研究

目的 探讨颈动脉钙化与缺血性卒中的关系.方法 回顾性收集急性缺血性卒中患者和同期住院的非急性卒中患者的人口统计学资料、血管危险因素和临床特征.所有患者均行64排螺旋CT检查,平扫数据被传入GE工作站,应用Smart积分软件评价颈动脉钙化情况.采用多变量logistic回归分析确定缺血性卒中的独立危险因素.采用受试者工作特征（receiver operator characteristic,ROC）曲线分析判断颈动脉钙化对急性缺血性卒中的预测价值.结果 共纳入86例急性缺血性卒中和89例非缺血性卒中患者（对照组）.缺血性卒中组与对照组比较,除既往卒中史外,年龄、性别和血管危险因素均无显著性差异.缺血性卒中组钙化积分[（338.57＆#177;77.35）分对（147.79＆#177;64.52）分;t=4.065,P=0.045]、总钙化体积[（372.22＆#177;78.73） mm3对（197.27＆#177;61.12）mm3;t =4.740,P=0.031]和钙化质量[（70.33＆#177;13.83）mg对（32.44＆#177;12.27） mg;t =6.673,P=0.011]均显著性高于对照组.在缺血性卒中患者中,症状侧颈动脉的钙化积分[（335.50＆#177;85.95）分对（312.73＆#177;90.61）分;t=0.052,P=0.820]、总钙化体积[（357.91＆#177;88.93）mm3对（311.71＆#177;81.43）mm3;t =0.071,P=0.791]和钙化质量[（59.68＆#177;17.36）mg对（51.29＆#177;18.69）mg;t=1.716,P=0.192]与非症状侧无显著性差异.多变量logistic回归分析显示,颈动脉钙化积分[优势比（odds ratio,OR）4.963,95％可信区间（confidence interval,CI）5.932 ～ 18.994;P=0.019]、总钙化体积（OR 5.967,95％ CI3.940 ～ 14.993;P=0.015）和钙化质量（OR 6.815,95％ CI4.703 ～21.946;P=0.007）是缺血性卒中的独立危险因素.对颈动脉钙化积分进行ROC曲线分析显示,当颈动脉钙化积分为231.25分时对急性缺血性卒中具有预测价值,敏感性为85.4％,特异性为89.9％,阳性预测值87.1％,阴性预测值为89.1％,ROC曲线下面积为0.891（95％ CI 0.808 ～0.913,P=0.027）.结论 颈动脉钙化为缺血性卒中的独立危险因素之一,颈动脉钙化积分对急性缺血性卒中有一定的预测价值.     

无功能性胰岛细胞瘤的CT诊断

目的 探讨无功能性胰岛细胞瘤(NFICT)的CT表现.方法 回顾性分析经手术并经病理证实的17例NFICT的CT平扫和增强扫描所见.增强剂采用非离子型碘对比剂90 mL,注射流率3mL/s,测量胰腺和肿瘤动、静脉双期CT值.结果 CT扫描全组均发现肿瘤.平扫时肿瘤与胰腺实质比较,2例肿瘤为低密度,11例为混合性低密度,4例为等密度.5例于肿瘤内见限局性钙化.增强扫描17例肿瘤均有程度不同的强化.动脉期明显强化5例,中等强化6例,轻度强化6例.结论 NFICT的CT平扫表现为界限清楚的肿瘤,部分瘤体内有钙化.增强扫描肿瘤均有程度不同的强化,从动脉期到门静脉期呈持续性强化是NFICT的特征性表现.     

47例原发性腹膜后肿瘤的临床诊治探讨

目的 探讨原发性腹膜后肿瘤(PRT)的诊治经验.方法 回顾性分析自2005年6月至2014年6月收治的47名腹膜后肿瘤患者一般临床资料、既往史、影像学检查、手术方式、术后病理、随访记录等资料.结果 B超诊断阳性率为85.0％,CT和MRI诊断阳性率为100％.开放手术组25例,肿瘤平均直径8.06cm,人平均手术时间为154.3min,人均术中出血量790.1 mL,人均术后住院天数11.8d.腔镜组22例,肿瘤平均直径6.84cm,人均手术时间153.9min,人均术中出血量289.2mL,人均术后住院天数9.0d.两组术中出血量和术后住院天数差异有统计学意义(P＜0.05).良性肿瘤27例(57.45％),恶性肿瘤20例(42.55％).恶性PRT完整切除组的5年生存率为40.0％ (4/10),姑息切除组为0(0/8),差异有统计学意义(P＜0.05).结论 影像学检查对PRT术前诊断至关重要,腹腔镜手术在术中出血以及术后恢复方面优于开放手术,完整切除肿瘤是治疗的关键和影响预后的重要因素.     

18F-FDG SPECT/CT与64排CT异机融合在结直肠癌诊断中的应用

目的 对比氟18-脱氧葡萄糖单光子发射计算机断层成像术（¹⁸F-FDG SPECT/CT）与GE 64排CT异机融合前后图像质量,探讨异机融合¹⁸F-FDG SPECT/CT（简称异机融合）诊断结直肠癌及TNM分期的优势。方法 36例经病理证实的结直肠癌患者接受¹⁸F-FDG SPECT/CT和异机64排CT检查,图像传输至后处理工作站,完成¹⁸F-FDG SPECT图像分别与同机低能量CT及异机64排CT图像融合。36例患者中,共65枚病灶,其中原发灶36枚,淋巴结转移灶19枚,远处转移灶10枚,并依此分为三组;分别对三组同机融合及异机融合图像中病灶边界是否清晰、与邻近脏器关系是否清晰、是否有伪影进行主观评分,同机融合及异机融合图像质量得分的比较采用Wilcoxon检验。结果 三组图像质量得分异机融合均高于同机融合,差异有统计学意义（z=-5.303和-3.858和-2.844,均P<0.01）。结论 结直肠癌原发灶、淋巴结转移灶、远处转移灶异机融合图像均优于同机融合图像,异机融合值得临床推广应用。     

虚拟耳镜对鼓室成形术前后鼓室结构的观察

目的 探讨虚拟耳镜在鼓室成形术中的临床评估作用.方法 应用虚拟耳镜观察耳病患者102例(204耳),72例(75耳)完成鼓室成形术和外耳道鼓室成形术,其中慢性中耳炎53例(55耳),先天性外耳道闭锁1 9例(20耳).结果 23耳慢性化脓性中耳炎胆脂瘤型,虚拟耳镜观察19耳听骨链破坏,手术证实23耳均有听骨腐蚀;32慢性化脓性中耳炎骨疡型,虚拟耳镜观察29耳听骨链不同程度破坏,手术证实23耳锤骨和砧骨侵蚀,11耳镫骨头或镫上结构缺失;20耳先天性外耳道闭锁,中耳畸形,术前提示18耳听骨畸形,2耳小鼓室无听骨链,手术证实17耳外耳道闭锁,听骨严重畸形,2耳镫骨缺失,1耳前庭窗闭锁.2耳术后突然听力下降,复查虚拟耳镜发现移植听骨与鼓膜脱离.虚拟耳镜与手术探查符合率,中耳炎为92%,先天性外耳道闭锁、中耳畸形为100%.结论 虚拟耳镜为鼓室成形术术前病变程度及术后疗效评估提供可靠的影像学依据.     

症状、CT和鼻声反射在慢性鼻窦炎组织重构诊断中的意义

目的探讨鼻塞症状、CT扫描Lund-Mackay评分和鼻声反射测量鼻黏膜充血指数与慢性鼻及鼻窦炎(chronic rhinosinusitis,CRS)组织重构程度之间的相关性,探讨三者在CRS组织重构诊断中的意义。方法选取CRS患者43例,应用视觉模拟评分(visual analogous scale,VAS)系统评价鼻塞症状;Lund- Mackay平分系统评价鼻窦CT扫描结果;鼻声反射测量获取鼻黏膜充血指数;钩突黏膜组织标本行鼻黏膜纤维化程度评分。应用统计学方法对其相关性进行分析。结果鼻塞症状严重程度与鼻黏膜纤维化程度之间无明显相关性(r=-0.046,P=0.77);CT评分与黏膜组织纤维化评分之间无相关性(r=0.132,P=0.40);鼻黏膜纤维化程度与鼻黏膜充血指数之间呈负相关(r=-0.348, P=0.022)。结论鼻黏膜充血指数能够反映病变黏膜的组织重构程度,辅助症状与CT检查指导CRS治疗策略。