Magnetic resonance imaging of rerouted pulmonary blood flow

Correction of structural defects of the heart associated with cyanotic heart disease often requires rerouting of systemic venous return into the pulmonary arteries and pulmonary venous return into the ventricles. Preliminary experience suggests that magnetic resonance imaging, through its superior depiction of the resultant complex anatomy, provides important supplemental information to echocardiography. Together, these noninvasive techniques may lessen the present need for repeat catheterization in children with surgically corrected cyanotic heart disease.     

Three-dimensional phase contrast magnetic resonance imaging validated to assess pulmonary artery flow in patients with chronic thromboembolic pulmonary hypertension

In this study, three-dimensional phase contrast magnetic resonance imaging (3D-PC MRI), a novel technique, was validated to assess pulmonary artery (PA) flow in patients with chronic thromboembolic pulmonary hypertension (CTEPH). The MR data of PAs from 3D-PC and two-dimensional PC (2D-PC) from before and after treatment for 3 patients with CTEPH were retrospectively analyzed. Additionally, 3D- and 2D-PC MR scans of PA were performed in 5 healthy volunteers. Correlation of stroke volumes (SVs) obtained by 3D-PC and 2D-PC was analyzed using Pearson’s correlation coefficients. There was an excellent correlation in the SV of main PA, left PA and right PA between 3D-PC and 2D-PC (main PA: r = 0.91, p < 0.01, left PA: r = 0.72, p < 0.01 and right PA: r = 0.77, p < 0.01). In conclusion, 3D-PC MRI was able to accurately quantify the PA flow in patients with CTEPH.     

Assessment of differential pulmonary blood flow using perfusion magnetic resonance imaging: comparison with radionuclide perfusion scintigraphy

OBJECTIVES: We sought to assess the agreement between lung perfusion ratios calculated from pulmonary perfusion magnetic resonance imaging (MRI) and those calculated from radionuclide (RN) perfusion scintigraphy. MATERIALS AND METHODS: A retrospective analysis of MR and RN perfusion scans was conducted in 23 patients (mean age, 60 +/- 14 years) with different lung diseases (lung cancer = 15, chronic obstructive pulmonary disease = 4, cystic fibrosis = 2, and mesothelioma = 2). Pulmonary perfusion was assessed by a time-resolved contrast-enhanced 3D gradient-echo pulse sequence using parallel imaging and view sharing (TR = 1.9 milliseconds; TE = 0.8 milliseconds; parallel imaging acceleration factor = 2; partition thickness = 4 mm; matrix = 256 x 96; in-plane spatial resolution = 1.87 x 3.75 mm; scan time for each 3D dataset = 1.5 seconds), using gadolinium-based contrast agents (injection flow rate = 5 mL/s, dose = 0.1 mmol/kg of body weight). The peak concentration (PC) of the contrast agent bolus, the pulmonary blood flow (PBF), and blood volume (PBV) were computed from the signal-time curves of the lung. Left-to-right ratios of pulmonary perfusion were calculated from the MR parameters and RN counts. The agreement between these ratios was assessed for side prevalence (sign test) and quantitatively (Deming-regression). RESULTS: MR and RN ratios agreed on side prevalence in 21 patients (91%) with PC, in 20 (87%) with PBF, and in 17 (74%) with PBV. The MR estimations of left-to-right perfusion ratios correlated significantly with those of RN perfusion scans (P < 0.01). The correlation was higher using PC (r = 0.67) and PBF (r = 0.66) than using PBV (r = 0.50). The MR ratios computed from PBF showed the highest accuracy, followed by those from PC and PBV. Independently from the MR parameter used, in some patients the quantitative difference between the MR and RN ratios was not negligible. CONCLUSIONS: Pulmonary perfusion MRI can be used to assess the differential blood flow of the lung. Further studies in a larger group of patients are required to fully confirm the clinical suitability of this imaging method.     

动态肺灌注显像评价特发性肺动脉高压的临床研究

目的 探讨动态PPI用于IPAH的临床应用价值.方法 2009年7月至2010年12月间20例经右心导管及肺动脉造影检查确诊为IPAH的连续病例和10名健康对照者,接受动态PPI.以双肺为ROI,得到时间-放射性曲线,计算显像剂从进入肺内到肺内放射性分布达到平衡的肺平衡时间(LET).组间比较采用t检验,LET与右心导管测得的血流动力学参数进行Pearson相关分析.结果 IPAH患者LET平均为(33.9 ±15.5)s,而健康对照组仅为(14.4±3.7)s,IPAH患者LET明显延长(t=5.340,P＜0.001).LET与mPAP、全肺阻力(TPR)间具有直线相关性(分别为r=0.566,P＜0.01和r=0.688,P＜0.05),与CI呈直线负相关(r=-0.480,P＜0.05).结论 动态PPI对于无创性评估IPAH血流动力学变化程度及右心功能具有一定的应用价值.     

Magnetic resonance imaging of myocardial contrast enhancement with MS-325 and its relation to myocardial blood flow and the perfusion reserve

PURPOSE: To determine with an intravascular contrast agent the relation between the rate of myocardial signal enhancement during the first pass (upslope) and myocardial blood flow (MBF), and to derive and validate a corrected perfusion reserve (PR) index from the upslope parameter. MATERIALS AND METHODS: Measurements of the upslope parameter for myocardial contrast enhancement with an intravascular contrast agent (MS-325) were performed in a porcine model with ameroid coronary constrictor. MBF was estimated with MRI and was validated against separate invasive measurements with labeled microspheres. PR indices were calculated from the upslope of the tissue curves. A new PR index was corrected by the time delay between appearance of the tracer and the upslope maximum. RESULTS: MBFs determined by MRI vs. MBFs measured with microspheres were in agreement within the 95% confidence intervals (CIs) for the identity relation. The new PR index slightly overestimated the MBF reserve by an average +1.4% (95% CI = -44% to +46%). The uncorrected PR index underestimated the MBF reserve by -33% (95% CI = -92% to +25%). CONCLUSION: A perfusion index derived from the maximum upslope of myocardial contrast enhancement produces accurate estimates of the PR if corrected by the time-to-maximum upslope.     

99Tcm-MAA肺灌注显像评价肺动脉血栓内膜剥脱术疗效

目的 应用99Tcm-大颗粒聚合白蛋白(MAA)肺灌注显像评价肺动脉血栓内膜剥脱术对慢性栓塞性肺动脉高压(CPTH)疗效,并与电子束CT(EBCT)进行对比.方法 9例CPTH患者,于手术前、术后早期(6～30 d)和术后远期(6～12个月)分别进行肺灌注显像,对图像进行逐个肺段的定性和半定量分析,比较手术前后肺血流灌注的变化,并与EBCT进行逐个肺段的对比分析.结果 术前99个肺段显示灌注异常,术后早期42个(42.4%)恢复正常,28个(28.3%)部分改善;术后远期完全恢复的肺段为69.7%(69/99个).术前全肺灌注缺损百分数(PPDs%)平均为(60.8±6.5)%,术后早期下降为(46.1±11.8)%(P＜0.01);术后远期进一步下降为(13.3±13.5)%(P＜0.01).按肺段统计,手术前后肺灌注显像与EBCT结果均符合为60.3%.结论 99Tcm-MAA肺灌注显像是评价肺动脉血栓内膜剥脱术后疗效的有效方法.     

笑气滥用患者的脑血流灌注显像

目的:探讨N 2O(笑气)滥用所致脑血流量(CBF)的改变。 方法:回顾性分析2017年12月至2018年10月间于中日友好医院就诊的24例笑气滥用患者[男9例,女15例,年龄18~32(24.0±8.9)岁]脑血流灌注显像图,计算各脑区(基底节、脑中央区、小脑、扣带回、额叶、内侧颞叶、枕叶、顶叶...     

Ventilation/perfusion imaging predicts response to balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

Annals of Nuclear Medicine - Although balloon pulmonary angioplasty (BPA) has emerged as an alternative treatment option for chronic thromboembolic pulmonary hypertension (CTEPH), it is followed in...     

The effect of pulmonary blood flow changes on oxygen‐enhanced lung magnetic resonance imaging

In this study, we investigated the effects of changes in pulmonary blood flow on oxygen‐enhanced lung magnetic resonance imaging. Increased pulmonary blood flow was produced by intravenous infusion of sildenafil (0.2 mg/kg) in 10 New Zealand white rabbits. Decreased pulmonary blood flow was produced by single subcutaneous injection of monocrotaline (60 mg/kg). A velocity‐encoded cine magnetic resonance imaging for pulmonary blood flow and an oxygen‐enhanced lung magnetic resonance imaging were performed at baseline, during sildenafil infusion, and after monocrotaline injection. We compared the baseline data to those obtained during sildenafil infusion and after monocrotaline injection for pulmonary blood flow changes and signal intensity enhancement ratios of oxygen‐enhanced lung magnetic resonance imaging. Wilcoxon's signed rank test was used for statistical analysis. There was a significant difference between pulmonary blood flow at baseline (418.6 ± 108.9 mL/min) and after sildenafil (491.9 ± 118.0 mL/min; P = 0.005) or between pulmonary blood flow at baseline and after monocrotaline administration (356.3 ± 85.8 mL/min; P = 0.017). However, there was no significant difference between the signal intensity enhancement ratios at baseline (23.8 ± 11.4%) and after sildenafil (24.0 ± 7.9%; P = 0.953) or the signal intensity enhancement ratios at baseline and after monocrotaline administration (22.7 ± 10.3%; P = 0.374). Changes in pulmonary blood flow had little effect on the signal intensity enhancement ratio of oxygen‐enhanced lung magnetic resonance imaging. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Magnetic resonance imaging in patients with panhypopituitarism

Primary panhypopituitarism consists of functional deficiency of the anterior pituitary lobe, which appears during infancy or adolescence. The magnetic resonance findings in 10 patients with a history of primary hopopituitarism are presented. The findings include: reduced pituitary size in all cases: partially (8 cases) or totally (2 cases) empty sella; thin (4 cases), partially visible (3 cases) or absent (2 cases) pituitary stalk; absence of the posterior lobe in 9 cases: bright spot corresponding to an ectopic posterior lobe in 8 cases. These findings are similar to those already reported in pituitary dwarfism and may help under-genesis of the pathogenesis of the disease: which seems to he related to a pituitary stalk lesion.     

99Tcm-N-NOET负荷和延迟门控心肌灌注显像对高血压患者的临床价值

Objective To investigate clinical significance of the 99Tcm-bis (N-ethoxy-N-ethyl-dithiocarbamato) nitridotechnetium(99Tcm-N-NOET) exercise and delayed myocardial perfusion imaging (MPI) in hypertensive patients. Methods Sixty patients with hypertension and 19 normal subjects were carried out 99Tcm-N-NOET exercise and delayed MPI, and analyzed the results of MPI, exercise electrocardiography (ECG), cardiac function parameters end-diastolic volume(EDV), end-systolic volume(ESV), left ventricular ejection fraction(LVEF), △ LVEF (LV EF exercis-LVEF delay) and coronary angiography(CAG). Results ① Sixty patients with hypertension, 22 cases(36.7%)of exercise ECG were abnormal, 16 cases (26.7%)were the chest tightness in exercise, 13 cases (21.7%) were blood pressure excessive reaction in exercise; control group, 2 cases (10.5%) of exercise ECG were abnormal, 1 case (5.3%, 1/19) was chest tightness in exercise,no per-son was blood pressure response in excessive. ②The positive rate of myocardial perfusion in hyper tensive group was significantly higher than the control group (31.75％ vs.5.30％, P<0.05). ③Cardial function parameters in hypertension group [exercise EDV =(79.75 ±29.10)ml, ESV =(28.82 ± 15.73)ml, LVEF =(65.78 ±1.27)%; delay EDV=(81.42±3.47)ml, ESV=(30.62±2.05)ml, LVEF=(64.20±9.70)%] and control group[exercise EDV=(79.63 ±21.65)ml, ESV=(27.37±10.71)ml, LVEF=(66.42±1.55)%; delay EDV=(82.89±4.96)ml,ESV=(31.42±3.06)ml, LVEF=(63.16 ±7.54)%] were no statistical difference(exercise EDV: t=0.161, ESV: t=0.112, LVEF: t=0.261; delay EDV: t=0.276, ESV: t=0.197, LVEF: t=0.184, P>0.05), △ LVEF<0%, 28 cases (46.7%) in hypertension group, 4 cases (21.1%) in control group, χ2=3.929, P<0.05; 11 cases (57.9%) in MPI positive group, 12 cases (29.3％) in MPI negative group, χ2=4.501, P<0.05. ④Nineteen hypertension underwent CAG, 11 cases were abnormal, 8 cases were normal. MPI results: 9 cases were ischemia, 10 cases were normal, and they were no statistical difference (χ2=0.25, P>0.05). The sensitivity,specificity and accuracy of 99Tcm-N-NOET MPI were 72.7％, 87.5％ and 78.9％. Conclusions ①99Tcm-N-NOET exercise and delayed MPI can diagnose whether hypertension patients with myocardial ischemia or not. ② △ LVEF of hypertensive patients reduced, △ LVEF is lower in hypertensive patients of MPI-positive.     

首次通过肺灌注显像对瓣膜性心脏病合并肺动脉高压的临床价值

目的　探讨首次通过肺灌注显像 (FPPPI)联合肺灌注显像 (PPI)对瓣膜性心脏病合并肺动脉高压 (PH)的临床价值。方法　以二尖瓣病变为主的瓣膜病患者 116例 ,术前均行右心导管、FPPPI及PPI、超声心动图检查。其中 10 5例患者术后 5～ 14d再次行FPPPI及PPI,33例患者于术后 3～ 11个月进行第 3次FPPPI及PPI复查。按右心导管测得的平均肺动脉压力 (MPAP)水平分为正常、轻度升高、中度升高、重度升高组。结果　① 116例患者FPPPI法所测肺平衡时间 (LET)、上肺野与下肺野比值 (S L)及超声心动图所测肺动脉压力 (EPAP)与右心导管所测肺动脉收缩压 (SPAP)的r值分别为0 85 6 ,0 5 0 3及 0 5 72 (P <0 0 1)。②以MPAP为标准 ,FPPPI、PPI及FPPPI PPI测定肺动脉压力的灵敏度分别为 94 7%、78 8%及 96 4 % ,特异性分别为 6 8 3%、5 2 8%及 72 7% ,准确性分别为 85 3%、70 7%及 89 7%。③ 10 5例患者术前与术后 5～ 14dLET分别为 (2 7 71± 10 85 )s和 (2 0 96± 6 2 5 )s(P <0 0 0 1) ;S L分别为 1 4 3± 0 4 1和 1 30± 0 35 (P <0 0 0 1)。④LET在MPAP轻度、中度、重度升高组的完全改善率分别为 4 7 6 %、34 5 %及 1 4例 ;部分改善率分别为 4 0 5 %、6 2 1%及 3 4例 (P <0 0 0 1)。S L在各组完     

Magnetic resonance perfusion imaging in malformations of cortical development

BACKGROUND: Malformations of cortical development vary in neuronal maturity and level of functioning. PURPOSE: To characterize regional relative cerebral blood volume (rCBV) and difference in first moment transit time (TTfm) in polymicrogyria and cortical tubers using magnetic resonance (MR) perfusion imaging. MATERIAL AND METHODS: MR imaging and dynamic T2*-weighted MR perfusion imaging were performed in 13 patients with tuberous sclerosis complex, 10 with polymicrogyria, and 18 controls with developmental delay but no macroscopic brain abnormality. Regions of interest were placed in cortical tubers or polymicrogyric cortex and in the contralateral normal-appearing side in patients with malformations. In "control" subjects, regions of interest were placed in the frontal and parietal lobes in both hemispheres. The rCBV and TTfm of the tuber/contralateral side (rCBV(R)TSC and DeltaTT(FM)TSC) as well as those of the polymicrogyria/contralateral side (rCBV(R)PMG and DeltaTT(FM)PMG) were assessed. The right-to-left asymmetry of rCBV and TTfm in the control group was also assessed (rCBV(R)Controls and DeltaTT(FM)Controls). RESULTS: There was no significant asymmetry between right and left rCBV or TTfm (P>0.05) in controls. There was significant reduction in rCBV(R)TSC compared to rCBV(R)Controls (P<0.05), but no significant difference in DeltaTT(FM)TSC compared to DeltaTT(FM)Controls (P>0.05). There were no significant differences between rCBV(R)PMG and rCBV(R)Controls (P>0.05) or DeltaTT(FM)PMG and DeltaTT(FM)Controls (P>0.05). CONCLUSION: Our findings imply that cerebral blood volume of polymicrogyria is similar to normal cortex, but there is reduced cerebral blood volume in cortical tubers. The lower rCBV ratio of cortical tubers may be related to known differences in pathogenetic timing of the underlying abnormalities during brain development or the presence of gliosis.     

Magnetic resonance imaging of myocardial perfusion and viability using a blood pool contrast agent

RATIONALE AND OBJECTIVES: A comprehensive cardiac magnetic resonance (MR) examination should comprise imaging of myocardial perfusion, viability, and the coronary arteries. Blood pool contrast agents (BPCAs) improve coronary MR angiography, whereas their potential for imaging of perfusion and viability is unknown. The abilities to noninvasively image myocardial perfusion and viability using the BPCA P792 (Guerbet, France) were tested in a closed-chest model of nonreperfused myocardial infarction in 5 pigs. MATERIALS AND METHODS: Two to 3 days after instrumentation, myocardial perfusion imaging with a saturation-recovery steady-state free precession technique and viability imaging with an inversion-recovery fast low-angle shot sequence were conducted on a 1.5-T MR scanner using the extracellular contrast agents (ECCA) Gd-DOTA (0.1 mmol Gd/kg) and blood pool contrast agent (BPCA) P792 (0.013 mmol Gd/kg). RESULTS: Perfusion defects were visualized in all pigs with good correlation between the ECCA and the BPCA (1.77 +/- 1.16 cm2 vs. 1.80 +/- 1.19 cm2, r = 0.959, P < 0.01). Reduced myocardial perfusion was detected using the ECCA up to 80 seconds after injection. In contrast, BPCA administration enabled visualization of perfusion defects on equilibrium perfusion imaging in all cases for 10 minutes. The size of myocardial infarction detected with viability MR imaging correlated well between the standard method (ECCA) and delayed-enhancement imaging with the BPCA (5.40 +/- 3.16 versus 5.52 +/- 3.13 cm3, r = 0.994, P < 0.002). CONCLUSIONS: The BPCA investigated in this study allows both reliable detection of perfusion defects on first pass and equilibrium perfusion imaging and characterization of viability after myocardial infarction. Thus, this contrast agent is suitable for a comprehensive cardiac MR examination.