Right ventricular regional function using MR tagging: Normals versus chronic pulmonary hypertension

Right ventricular (RV) regional function, in both normal and diseased states, is not well characterized. Using 1D MR myocardial tagging, RV and septal intramyocardial segmental shortening was noninvasively measured in ten healthy subjects and in seven patients with chronic pulmonary hypertension. The normal RV free wall regional shortening was not uniform. A pattern of increasing RV free wall short-axis shortening was found from the RV outflow tract to the RV apex, and a more complex pattern of RV free wall long-axis shortening was observed. Both regional short- and long-axis shortening were globally reduced in pulmonary hypertension patients, with the greatest decreases in the RV outflow tract and in the basal septal wall region. Regional RV function can be quantitatively evaluated using MR tagging to determine the impact of chronic pulmonary hypertension on RV performance.     

Infection imaging using whole-body FDG-PET

The purpose of this study was to evaluate fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of soft tissue and bone infections. Forty-five PET examinations in 39 patients (26 male, 13 female, age range 27–86 years) with suspected infectious foci were examined with whole- or partial-body PET scans using FDG. Twenty-seven scans were done in patients with soft tissue and 18 in patients with bone infections. Corrected and uncorrected transaxial PET images were acquired. Seven hundred and twelve body regions in these 45 PET scans were evaluated. Pathological findings were graded using a confidence scale from A to E (A, definitive infection; E, no infection). Disease status was defined in all patients by culture, biopsy or surgery and clinical follow-up. In 45 PET scans there were 40 true-positive, four false-positive and one false-negative findings. Twelve foci suspected to be infectious in nature on the basis of other imaging examinations were identified as negative by PET, thus representing true-negative findings. Sensitivities for the patients with soft tissue (STI) and bone infections (BI) and for the pooled data were 96%, 100% and 98%, respectively. As the calculation of specificity is not straightforward, it was calculated on a per lesion as well as on a per body region basis to permit estimation of an upper and a lower limit. On a per lesion basis, specificities were 70% (STI), 83% (BI) and 75% for the pooled data and on a per body region basis (dividing the body into 22 regions) they were 99% (STI), 99% (BI) and 99% for the pooled data. One false-negative result was found in a patient with cholangitis. It is concluded that PET appears to be a highly sensitive method to detect infectious foci. Specificity is more difficult to estimate, but is probably in the range from 70% to above 90%. Received 22 November 1999 and in revised form 20 March 2000     

Infection imaging using whole-body FDG-PET

The purpose of this study was to evaluate fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of soft tissue and bone infections. Forty-five PET examinations in 39 patients (26 male, 13 female, age range 27-86 years) with suspected infectious foci were examined with whole- or partial-body PET scans using FDG. Twenty-seven scans were done in patients with soft tissue and 18 in patients with bone infections. Corrected and uncorrected transaxial PET images were acquired. Seven hundred and twelve body regions in these 45 PET scans were evaluated. Pathological findings were graded using a confidence scale from A to E (A, definitive infection; E, no infection). Disease status was defined in all patients by culture, biopsy or surgery and clinical follow-up. In 45 PET scans there were 40 true-positive, four false-positive and one false-negative findings. Twelve foci suspected to be infectious in nature on the basis of other imaging examinations were identified as negative by PET, thus representing true-negative findings. Sensitivities for the patients with soft tissue (STI) and bone infections (BI) and for the pooled data were 96%, 100% and 98%, respectively. As the calculation of specificity is not straightforward, it was calculated on a per lesion as well as on a per body region basis to permit estimation of an upper and a lower limit. On a per lesion basis, specificities were 70% (STI), 83% (BI) and 75% for the pooled data and on a per body region basis (dividing the body into 22 regions) they were 99% (STI), 99% (BI) and 99% for the pooled data. One false-negative result was found in a patient with cholangitis. It is concluded that PET appears to be a highly sensitive method to detect infectious foci. Specificity is more difficult to estimate, but is probably in the range from 70% to above 90%.     

Evaluation of mechanical dyssynchrony and myocardial perfusion using phase analysis of gated SPECT imaging in patients with left ventricular dysfunction

Background. Using phase analysis of gated single photon emission computed tomography (SPECT) imaging, we examined the relation between myocardial perfusion, degree of electrical dyssynchrony, and degree of SPECT-derived mechanical dyssynchrony in patients with left ventricular (LV) dysfunction. Methods and Results. We retrospectively examined 125 patients with LV dysfunction and ejection fraction of 35% or lower. Fourier analysis converts regional myocardial counts into a continuous thickening function, allowing resolution of phase of onset of myocardial thickening. The SD of LV phase distribution (phase SD) and histogram bandwidth describe LV phase dispersion as a measure of dyssynchrony. Heart failure (HF) patients with perfusion abnormalities have higher degrees of dyssynchrony measured by median phase SD (45.5° vs 27.7°, P<.0001) and bandwidth (117.0° vs 73.0°, P=.0006). HF patients with prolonged QRS durations have higher degrees of dyssynchrony measured by median phase SD (54.1° vs 34.7°, P<.0001) and bandwidth (136.5° vs 99.0°, P=.0005). Mild to moderate correlations exist between QRS duration and phase analysis indices of phase SD (r=0.50) and bandwidth (r=0.40). Mechanical dyssynchrony (phase SD >43°) was 43.2%. Conclusions. HF patients with perfusion abnormalities or prolonged QRS durations have higher degrees of mechanical dyssynchrony. Gated SPECT myocardial perfusion imaging can quantify myocardial function, perfusion, and dyssynchrony and may help in evaluating patients for cardiac resynchronization therapy. (J Nucl Cardiol 2008;15:663-70.) This study was funded by a research grant from the Medtronic-Duke Strategic Alliance, and Dr Trimble is the primary investigator.     

肺动脉高压病人左右心室心肌灌注储备与右心室功能及肺血流动力学之间的相关性

目的应用腺苷负荷MR心肌灌注成像评价肺动脉高压(PAH)病人右心室(RV)与左心室(LV)间心肌灌注储备与心室功能及肺血流动力学的关系。材料与方法本研究符     

Quantitative analysis of left ventricular dyssynchrony using cardiac computed tomography versus three-dimensional echocardiography

Objectives

We investigated whether cardiac computed tomography (CCT) can determine intraventricular dyssynchrony in comparison to real-time three-dimensional echocardiography (RT3DE) in patients who are considered for cardiac resynchronisation therapy (CRT).

Methods

35 patients considered for CRT were examined. Left ventricular (LV) dyssynchrony was quantified by calculating the standard deviation index (SDI) of 17 myocardial LV segments by RT3DE and ECG-gated contrast-enhanced 64-slice dual-source CCT. For both analyses the same software algorithm (4D LV-Analysis) was used.

Results

Close correlations were observed for end-systolic volume, end-diastolic volume and LV ejection fraction between the two techniques (r?=?0.94, r?=?0.92 and r?=?0.95, respectively, P?P?P?P?P?Conclusion Quantitative assessment of LV dyssynchrony is feasible by CCT. Owing to its higher reproducibility and faster analysis time compared with RT3DE, this technique may represent a valuable alternative for dyssynchrony assessment.

Key Points

? Quantitative assessment of left ventricular dyssynchrony is feasible by cardiac computed tomography (CCT). ? This technique has been compared with real-time three-dimensional echocardiography (RT3DE). ? Reproducibility is significantly higher for CCT compared with RT3DE. ? Time spent for analysis is significantly shorter for CCT. ? Computed tomography may represent a valuable alternative to ultrasound for dyssynchrony assessment.     

Assessment of lung glucose uptake in patients with systemic lupus erythematosus pulmonary arterial hypertension: a quantitative FDG-PET imaging study

Annals of Nuclear Medicine - Pulmonary arterial hypertension (PAH) is a recognized complication of systemic lupus erythematosus (SLE-PAH) patients and its lung pathology shares similarity to...     

Assessment of left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review the phase analysis methodology is described, and its up-to-date validations are summarized.     

应用定量组织速度及组织追踪成像评价心衰患者心肌不同步性

目的探讨应用定量组织速度及组织追踪成像评价心衰患者左心室心肌收缩、舒张功能不同步性的可行性。方法选取26例心力衰竭患者及30例正常对照组，应用QTVI成像软件和TT分析软件，在心尖四腔心，取后间隔及侧壁基底段（B）和中段（M）心肌分别放置取样点，测量收缩期及舒张期的心肌运动速度及组织位移的达峰时间，计算相同节段不同室壁间及不同节段相同室壁间的时间差。结果与对照组比较，心衰组收缩期速度及组织位移的达峰时间明显延长，舒张早期速度达峰时间无显著差异性，舒张晚期速度达峰时间明显缩短，而收缩期及舒张期速度及组织位移的时间差明显延长。结论心力衰竭患者存在左心室收缩及舒张的不同步性，定量组织速度及组织追踪不失为早期、精确、无创、定量评价其不同步性的方法。     

CT肺动脉成像评价慢性血栓栓塞性肺动脉高压栓塞指数及右心功能

目的：以选择性肺动脉造影及右心导管为标准,探讨多层螺旋计算机断层肺动脉成像（CTPA）评价慢性血栓栓塞性肺动脉高压（CTEPH）及右心功能的价值。方法：回顾性收集确诊CTEPH的患者24例,均行右心导管及肺动脉造影、CTPA及超声心动图检查。结果：CT Qanadli栓塞指数为（37.16±8.77）%,CT Mastora栓塞指数为（38.14±21.56）%,Qanadli栓塞指数高于Mastora栓塞指数（Z=-4.107,P=0.000）,且二者正相关（r=0.734,P=0.000）。CTPA测得主肺动脉/升主动脉直径比与右心导管测定肺动脉平均压（mean pulmonary arterial pressure,mPAP）正相关（r=0.461,P=0.036）。CTPA测定右心室前壁厚度与mPAP成正相关（r=0.515,P=0.018）。CTPA测得肺动脉直径大于超声测肺动脉内径（t=3.485,P=0.002）,且正相关（r=0.588,P=0.002）。CTPA测得右心室最大短轴直径大于超声测右室横径（t=2.647,P=0.016）,且正相关（r=0.429,P=0.031）。CTPA测定右室前壁厚度小于超声测值（t=3.768,P=0.001）,且成正相关（r=0.551,P=0.004）。CTPA测室间隔厚度略低于超声测室间隔厚度（t=2.941,P=0.007）,两组资料正相关（r=0.751,P=0.000）。Qanadli栓塞指数和Mastora栓塞指数与肺动脉压、主肺动脉直径、肺动脉/主动脉直径比、右室横径、右室前壁厚度等参数均无相关性（P〉0.05）。结论：CT肺动脉造影不仅能够明确诊断慢性血栓性肺栓塞,而且能够提供肺动脉树的阻塞程度、右心功能改变信息,为临床决策和治疗提供更多的信息,但慢性血栓性肺动脉高压肺栓塞程度与右心功能无关。     

Two cases of pulmonary paragonimiasis on FDG-PET CT imaging

Positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) is useful in cancer diagnosis owing to its sensitivity to the differences in glucose metabolic rate between benign and malignant diseases, especially in the lung. One pitfall in PET imaging of lung disease, however, is the overlap in metabolic rate of inflammatory and neoplastic entities. Paragonimiasis is a food-borne parasitic disease that causes the pulmonary and pleural inflammation. We present two cases of pulmonary paragonimiasis that showed high uptake suggestive of tumor on FDG-PET CT images, both confirmed on histopathology by visualization of Paragonimus westermani eggs in the involved tissues.     

Left ventricular dyssynchrony assessed by two three-dimensional imaging modalities: phase analysis of gated myocardial perfusion SPECT and tri-plane tissue Doppler imaging

Purpose To compare left ventricular (LV) dyssynchrony assessment by phase analysis from gated myocardial perfusion SPECT (GMPS) with LV dyssynchrony assessment by tri-plane tissue Doppler imaging (TDI). Baseline LV dyssynchrony assessed with standard deviation (SD) of time-to-peak systolic velocity of 12 LV segments (Ts-SD) with TDI has proven to be a powerful predictor of response to CRT. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle. Methods Forty heart failure patients, referred for evaluation of potential eligibility for CRT, underwent both 3D echocardiography, with tri-plane TDI, and resting GMPS. From tri-plane TDI, Ts-SD was used as a validated parameter of LV dyssynchrony and compared with different indices (histogram bandwidth, phase SD, histogram skewness and kurtosis) derived from phase analysis of GMPS. Results Histogram bandwidth and phase SD showed good correlation with Ts-SD (r=0.77 and r=0.74, p<0.0001, respectively). Patients with substantial LV dyssynchrony assessed with tri-plane TDI (Ts-SD ≥33 ms) had also significantly higher values of histogram bandwidth and phase SD. Conclusions The results of this study support the use of phase analysis by GMPS to evaluate LV dyssynchrony. Histogram bandwidth and phase SD showed the best correlation with Ts-SD assessed with tri-plane TDI and appeared the most optimal variables for assessment of LV dyssynchrony with GMPS.     

Quantitative assessment of tumor metabolism using FDG-PET imaging

Positron emission tomography using the glucose analog fluorine-18 fluorodeoxyglucose (FDG-PET) provides a unique means of non-invasive assessment of tumor metabolism. Several approaches, of varying complexity, can be applied for quantitative image analysis. Previous studies have demonstrated that "standardized uptake values" (SUV) and simplified tracer kinetic modeling, using the "Patlak-Gjedde"-analysis, provide highly reproducible parameters of tumor glucose utilization. Quantification of regional FDG uptake gives complementary information to visual image interpretation and provides objective criteria for differentiation between benign and malignant lesions. Moreover, quantification of tumor glucose metabolism is essential for assessment of therapy induced changes. Clinical studies in breast cancer and lymphoma suggest that serial FDG-PET studies allow the prediction of response early in the course of chemotherapy. Therefore, FDG-PET may be helpful in patient management by avoiding ineffective chemotherapy and supporting the decision to continue dose intense regimes. In addition, FDG-PET allows non-invasive assessment of tumor viability following chemo- and radiotherapy which permits individualized therapy management.     

Right ventricular function in patients with acute pulmonary embolism: analysis with electrocardiography-synchronized multi-detector row CT

PURPOSE: To prospectively assess electrocardiography (ECG)-synchronized multi-detector row computed tomography (CT) for the evaluation of right ventricular (RV) function in patients suspected of having pulmonary embolism (PE). MATERIALS AND METHODS: All patients gave informed consent after the study details, including radiation exposure, were explained; institutional ethical committee approval was obtained. Nonsynchronized multi-detector row CT of the chest was performed in 66 consecutive patients (29 men, 37 women; mean age, 58 years+/-15 [standard deviation]) who were suspected of having PE. ECG-synchronized cardiac multi-detector row CT was performed to assess cardiac function. Dimension ratios for the RV and left ventricle (LV) were measured on nonsynchronized transverse and angulated four-chamber views. Furthermore, the RV end-diastolic and end-systolic volumes were measured on ECG-synchronized multi-detector row CT scans. An independent samples t test was performed to compare the mean value of different groups. An analysis of variance post hoc test was performed to investigate whether the values of the variables varied between groups. RESULTS: PE was detected in 29 of 66 patients. The location of PE was categorized as central (n=17) or peripheral (n=12). The RV/LV dimension ratio was larger on the four-chamber view (P=.002), and RV end-systolic volume was larger (P=.01) and ejection fraction was lower (P=.01) in patients with PE. The RV end-systolic volumes and RV/LV volume ratios, as assessed by using ECG-synchronized multi-detector row CT, showed significant differences (P<.005) between patients with central PE and those with peripheral PE. However, the RV/LV dimensions on nonsynchronized images revealed no significant differences. CONCLUSION: Retrospective ECG-synchronized multi-detector row CT facilitates detection of RV dysfunction, depending on pulmonary embolus location.     

The prognostic value of left ventricular mechanical dyssynchrony using gated myocardial perfusion imaging in patients with end-stage renal disease

Background

Prior studies show that left ventricular mechanical dyssynchrony (LVD), measured by gated SPECT myocardial perfusion imaging (MPI), identifies patients with end-stage renal disease (ESRD) at higher risk for all-cause mortality but these were in small number of patients. We sought to assess the interaction between LVD and LV perfusion pattern in risk-stratification of a large sample size of patients with ESRD.

Methods

From the renal transplantation database maintained at the University of Alabama at Birmingham, we identified consecutive patients with ESRD who had gated SPECT MPI between 2003 and 2007. MPIs were reprocessed to derive LV ejection fraction (EF), perfusion defect size, and LVD [phase bandwidth (BW) and phase standard deviation (SD)]. The primary end-point was all-cause mortality, which was prospectively collected and verified against the social security death index database.

Results

There were 828 patients aged 52.6 ± 0.36 years (45% were women and 60% had diabetes mellitus). The LVEF was 54.8 ± 0.4% and the perfusion pattern was abnormal in 334 patients (41%). During a follow-up period of 61 ± 0.9 months, 230 patients (28%) received renal transplants and 290 patients (35%) died. The phase BW (73.1 ± 2.6° vs 66.3 ± 1.8°, P = .02) and SD (25.2 ± 0.8° vs 23.4 ± 0.5°, P = .06) were greater in patients who died than those who survived indicating greater dyssynchrony. Patients with phase BW >56° or SD ≥21° (median values) had worse 5-year survival (64% vs 72%, and 66% vs 71%, log-rank P = .005 and P = .07, respectively). After adjusting for demographics, co-morbidities, LVEF, and perfusion pattern, phase BW was associated with worse outcome (hazard ratio 1.289 95% CI 1.010-1.644, P = .04).

Conclusions

LVD by phase analysis of gated SPECT MPI provides prognostic value in ESRD beyond myocardial perfusion and EF.     

SPECT myocardial perfusion imaging for the assessment of left ventricular mechanical dyssynchrony

Phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is an evolving technique for measuring LV mechanical dyssynchrony. Since its inception in 2005, it has undergone considerable technical development and clinical evaluation. This article reviews the background, the technical and clinical characteristics, and evolving clinical applications of phase analysis of gated SPECT MPI in patients requiring cardiac resynchronization therapy or implantable cardioverter defibrillator therapy and in assessing LV diastolic dyssynchrony.     

Left ventricular diastolic dyssynchrony assessed with phase analysis of gated myocardial perfusion SPECT: a comparison with tissue Doppler imaging

Purpose

The aim of the current study was to evaluate the feasibility of phase analysis on gated myocardial perfusion SPECT (GMPS) for the assessment of left ventricular (LV) diastolic dyssynchrony in a head-to-head comparison with tissue Doppler imaging (TDI).

Methods

The population consisted of patients with end-stage heart failure of New York Heart Association functional class III or IV with a reduced LV ejection fraction of ??35%. LV diastolic dyssynchrony was calculated using TDI as the maximal time delay between early peak diastolic velocities of two opposing left ventricle walls (diastolic mechanical delay). Significant LV diastolic dyssynchrony was defined as a diastolic mechanical delay of >55?ms on TDI. Furthermore, phase analysis on GMPS was performed to evaluate LV diastolic dyssynchrony; diastolic phase standard deviation (SD) and histogram bandwidth (HBW) were used as markers of LV diastolic dyssynchrony.

Results

A total of 150 patients (114 men, mean age 66.0?±?10.4?years) with end-stage heart failure were enrolled. Both diastolic phase SD (r?=?0.81, p?r?=?0.75, p?55?ms) showed significantly larger diastolic phase SD (68.1?±?13.4° vs. 40.7?±?14.0°, p?p?Conclusion Phase analysis on GMPS showed good correlations with TDI for the assessment of LV diastolic dyssynchrony.