Measurement of stroke volume and cardiac output within a single breath hold with echo-planar MR imaging

The measurement of cardiac output and ejection fraction is useful in the treatment of diverse cardiac and cardiopulmonary disease states. Although several techniques are available for accurate measurement of left ventricular parameters, assessment of the right ventricle is less well represented. No single method is overwhelmingly superior, each having different strengths and weaknesses. In the present study, the applicability of an echo-planar magnetic resonance (MR) imaging method in which a complete volumetric measurement of the right and left ventricles may be obtained during 12 heartbeats is demonstrated. This rapidity permits imaging during a 15-second breath hold. The authors show in 12 volunteers that breath-hold echo-planar volume measurements of both ventricles were consistent with results obtained with conventional MR imaging methods.     

Automated myocardial edge detection on MR images: Accuracy in consecutive subjects

The authors previously demonstrated the feasibility of graph-searching-based automated edge detection in cardiac magnetic resonance (MR) imaging. To further assess the clinical utility of this method, unselected images from 11 consecutive subjects undergoing clinically indicated (except for one healthy volunteer) short-axis spin-echo MR imaging were analyzed. A total of 142 images from the 11 subjects, encompassing the left ventricle from apex to outflow tract, were analyzed. The computer algorithm correctly identified complete endocardial and epicardial contours in 121 of 142 images (85%). Correlations between observerbraced and computer-derived epicardial areas for all images were good (r = .71 for epicardium, r = .83 for endocardium); they improved for a subset of higherquality images (r = .82 for epicardium, r = .92 for endocardium). The authors conclude that the current data further support the usefulness of computer digital image processing in geometric analysis of cardiac MR image data.     

Quantification of global left ventricular function: comparison of multidetector computed tomography and magnetic resonance imaging. a meta-analysis and review of the current literature

Cardiac morbidity and mortality are closely related to cardiac volumes and global left ventricular (LV) function, expressed as left ventricular ejection fraction. Accurate assessment of these parameters is required for the prediction of prognosis in individual patients as well as in entire cohorts. The current standard of reference for left ventricular function is analysis by short-axis magnetic resonance imaging. In recent years, major extensive technological improvements have been achieved in computed tomography. The most marked development has been the introduction of the multidetector CT (MDCT), which has significantly improved temporal and spatial resolutions. In order to assess the current status of MDCT for analysis of LV function, the current available literature on this subject was reviewed. The data presented in this review indicate that the global left ventricular functional parameters measured by contemporary multi-detector row systems combined with adequate reconstruction algorithms and post-processing tools show a narrow diagnostic window and are interchangeable with those obtained by MRI.     

MRI of the lungs in children

Lung diseases of children often need diagnostic imaging beyond X-ray. Although CT is considered the gold standard of lung imaging, MRI is sufficient to answer most of the questions raised. After all, the exposure to radiation caused by one CT examination corresponds to approximately the effective dose of 200 chest radiographs.     

Cardiac ejection fraction: phantom study comparing cine MR imaging, radionuclide blood pool imaging, and ventriculography.

The accuracy and reproducibility of cardiac ejection fraction (EF) measurements based on cine magnetic resonance (MR) imaging, radionuclide multigated acquisition (MUGA) blood pool imaging, and angiographic ventriculography were evaluated by comparing them with a volumetrically determined standard. A biventricular, compliant, fluid-filled heart phantom was developed to mimic normal cardiac anatomy and physiology. Ventricular EFs were measured with cine MR imaging by summation of nine contiguous 10-mm-thick sections in short and long axis, with single-plane ventriculography, and with MUGA. Three measurements were performed with each modality for each of three EFs. Ventriculography was least accurate, with average relative errors ranging from 7.9% for the largest EF to 60.1% for the smallest. Cine MR was most accurate, with average relative errors ranging from 4.4% to 8.5%. MUGA EF measurements showed good correlation, with average relative errors ranging from 7.1% to 22.4%. Comparison of the error variances for the three modalities with the F test revealed that MR and MUGA EF measurements were significantly more accurate than those based on ventriculography (P less than .01). No significant difference was demonstrated between the accuracy of short- and long-axis cine MR acquisitions.     

Parametric visualization methods for the quantitative assessment of myocardial motion

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate three-dimensional (3D) and four-dimensional (4D) techniques for quantifying and visualizing myocardial motion. MATERIALS AND METHODS: The 4D method was performed by using 3D reconstructions of the complete, in vivo, canine heart before and after acute myocardial infarction. Images were obtained with the Dynamic Spatial Reconstructor (1-3) at 15 time points throughout one cardiac cycle. The authors used 0.75-mm-thick sections to allow creation of deformable models at each time point. For the 3D method, electron-beam computed tomographic reconstructions were obtained in anesthetized pigs from eight adjacent short-axis sections of the left ventricle. Data were acquired before and after selective microembolization of the left anterior descending coronary artery at 11 time points throughout one complete cardiaccycle. The authors used 8-mm-thick sections, which did not enable the use of the volumetric 4D approach with deformable models. For the 3D method, images were processed by radially dividing the tomographic images into small circumferential sectors. Color encoding was used for the derived local magnitudes of wall dynamics. RESULTS: The 4D method provided endocardial peak velocities, excursions, and strains throughout systole and diastole. The 3D method provided regional thickness or regional rates of left ventricular wall thickening throughout the cardiac cycle. CONCLUSION: Functional parametric maps of disturbances in regional contractility and relaxation facilitate appreciation of the effect of altered structure-to-function relationships in the myocardium.     

老年渔民肺肿瘤患者术后心肺功能变化的临床研究

目的 研究老年渔民肺肿瘤肺切除患者在静息及运动负荷状态下手术前后的心肺功能变化规律,为放宽老年肺肿瘤患者手术指征提供依据.方法 41例因患肺肿瘤行肺叶切除术的患者分为老年组24例(≥60岁)、中青年组17例(<60岁),分别于术前3～5 d和术后3～6个月在患者日常生活无障碍时,采用心肺功能仪和多普勒超声技术在静息及运动负荷状态下测定心肺功能,指标包括心率(HR)、左心室舒张末期容积(LVEDV)、每搏量(SV)、心输出量(CO)、左心室射血分数(LVEF)、呼吸频率(RR)、潮气量(VT)、每分通气量(VE)和氧摄取量(VO2),并对其结果进行分析比较.结果 所有患者在静息和运动负荷状态下心功能参数LVEDD和SV术后较术前均有明显降低(P<0.01),静息状态下HR、RR、VT手术前后比较差异有统计学意义(P<0.05或P<0.01).进行年龄分组后,两组在静息状态下术后SV、VT均减小,CO、VE、VO2手术前后差异有统计学意义(P<0.01);运动负荷状态下术后两组VO2均减少,但老年组VE减少明显(P<0.01).结论 肺切除术后静息状态时CO和VE分别通过HR和RR的增加得到补偿,保证了氧摄取量,而术后运动负荷状态下CO和VE的减少不能通过HR和RR得到代偿,老年组VO2降低主要是VE减少所致,而中青年组则是由CO减少所致.     

Quantitation of cardiac dimensions from ECG-synchronized MRI studies

The ability to measure the heart is useful for evaluation of a wide variety of conditions. Magnetic resonance imaging (MRI) has a number of characteristics that make it potentially one of the best methods for obtaining cardiac measurements, in particular its ability to produce uniformly highquality images in any desired plane. It is important that techniques for measurement be standardized so that methods are reproducible from patient to patient, allowing normal standards to be established, and from examination to examination in the same patient, so that serial measurements accurately reflect change in cardiac status.     

Gallbladder response to a second dose of cholecystokinin during the same imaging study

Patients on total parenteral nutrition or after prolonged fasting may require treatment with cholecystokinin (CCK) prior to hepatobiliary imaging. Some may also require evaluation of gallbladder (GB) contractility, and the need for a second dose of CCK may arise. It is not clear whether gallbladder function can be adequately evaluated with CCK when a previous CCK dose had already been administered. We studied ten normal subjects to evaluate GB response to a second CCK injection. The subjects received 20 g/kg sincalide in a 3-min infusion prior to administration of technetium-99m disofenin. They then received an identical sincalide dose at 60 min postinjection, and imaging was continued for another 30 min to quantify GB contraction. Gallbladder ejection fraction (GBEF) values ranged from 42–98% (mean: 71.5±19%). Pretreatment with CCK does not preclude GB contraction evaluation with a second dose of CCK. Expected GBEF values are similar to those obtained with single CCK injections.     

肺癌MRI与癌细胞核DNA含量及S期分数的相关性

探讨肺癌ＭＲＩ信号及形态特征与ＤＮＡ倍体的关系。材料和方法：２６例原发性支气管肺癌患者,术前用Ｒｅｓｏｎｅｘ０．３８Ｔ磁共振成义行冠状面及横断面成像（ＳＥ Ｔ１ＷＩ和ＧＲ）,增强后行横断面ＳＥ Ｔ１ＷＩ。术后肺癌标本用细胞图像分析仪,测定每例患者的ＤＮＡ含量及Ｓ期分数（ＳＰＦ）。结果：未增强Ｔ１ＷＩ异倍体肿瘤信号强度比显著大于二倍体肿瘤的信号强度比。异位体肿瘤的ＳＰＦ值也显著大于二倍体肿瘤,ＭＲＩ     

A fully automated determination of the left ventricular region of interest in nuclear angiocardiography

The precise delineation of the left ventricular projection area is an essential part in the quantitative analysis of nuclear angiocardiograms. We have devised an algorithm that permits automation of this step, based on a one-dimensional Laplace operator whose kernel is 2, 2, −2, −4, −2, 2, 2. The operator characteristically enhances “valleys” more than edges and, therefore, favors septal and the valve plane detection. The operator is applied vertically, horizontally, and along both diagonals. Each pass is immediately followed by a local maximum search during which the image resulting from the Laplacian operator is reduced to a binary one, with zeros everywhere except where a local maximum was found along the path of the operator. This resultant image yields a closed “edge” around the left ventricle, even though many structures outside the left ventricle are also delineated. However, the centroid of the ventricle is defined from functional criteria and the region of interest is defined from centroid to first edge. The method has been applied to first-pass and gated studies in anterior and 45° left anterior oblique views. In 100 successive cases the ejection fraction obtained automatically was compared to the manual result. The regression equation yielded the relation: automatic method (%)=1.7+1.0 manual method (%)±2% (r=0.995), which is not significantly different from the identity relation. The failure rate was low (13%) but varied from 28% in first-pass studies in the anterior view, to less than 8% in gated studies in the left anterior oblique projection.     

侧脑室脑膜瘤的CT和MRI诊断

目的：提高侧脑室内脑膜瘤的CT和MRI诊断的正确性。材料和方法：本文收集了经手术和病理证实的侧脑室脑膜瘤16例。9例作CT检查，12例作MRI检查，其中5例同时作CT和MRI检查。结果：（1）侧脑室脑膜瘤具有典型的CT和MRI表现，即：病灶大多为类圆形（81．2％，13／16），体积较大，边界清晰。CT平扫为均匀略高密度影，增强呈均匀明显强化（77．8％，7／9）。MRI表现为T1WI呈等信号（75％，9／12）、低信号（25％，3／12），T2WI呈略高信号（41．7％，5／12）、等信号（50％，6／12）、低高混杂信号（8．3％，1／12），增强呈均匀强化（66．7％，8／12），和不均匀强化（33．3％，4／12）。可有囊变、坏死和钙化。可见瘤周脑实质水肿（43．8％，7／16）。（2）侧脑室脑膜瘤好发于20－60岁，女性多见，本组男女之比为3:13。（3）侧脑室脑膜瘤好发于侧脑室三角区。（4）16例侧脑室脑膜瘤病理类型均为纤维型。结论：侧脑室脑膜瘤根据其CT和MRI特点，结合临床和发病部位和发病年龄、性别，可以提高诊断正确率。其病理类型均为纤维型。     

心胸比率与左心室容积及收缩功能的相关性研究

目的:探讨立位及卧位心胸比率(CTR)在评估左心室大小及收缩功能中的价值.方法:回顾性分析184例行心脏远达片及双源CT冠脉造影的疑似冠心病患者的病例资料.两名医师独立在心脏远达片及双源CT定位像上测量CTRCR及CTRCT.左心室容积及收缩功能参数如左心室舒张末期容积(LVEDV)、收缩末期容积(LVESV)、LVEDV指数(LVEDVI)、LVESV指数(LVESVI)及左心室射血分数(LVEF)等利用半自动心功能处理软件在双源CT冠脉造影图像上获得.然后采用线性相关分析CTRCR及CTRCT的关系及两者与左心室容积及收缩功能的相关性.结果:CTRCT和CTRCR呈正相关(r2=0.61,P＜0.0001),但CTR除了与LVEDVI呈正相关外,与其它左心室容积及收缩功能参数均无相关性.左心容积参数LVEDV、LVEDVI、LVESV、LVESVI和LVEF均呈负相关(r=-0.48,r=-0.54,r=-0.81,r=-0.83,以上P＜0.05).结论:立位及卧位CTR可以互相预测,但CTR不能作为预测左心室容积及收缩功能的指标.     

系统性硬化症患者静息肺功能的变化

目的:比较分析系统性硬化症(SSc)患者有、无呼吸道症状等不同状态时静息肺功能的变化,以观察其不同阶段肺损害的程度.方法:选择临床确诊的SSc患者68例,男10例,女58例,平均年龄41.5岁,测定静息肺功能的变化.结果:无任何呼吸道症状组胸片异常占23.2%,弥散功能障碍高达91.1%,限制型通气功能障碍占42.3%,小气道功能障碍占56.8%.有呼吸道症状组胸片异常占66.7%.无呼吸道症状组和胸片正常组SSc患者实测值占预计值%均有2项均值(FEF_(25%～75%)和DLco)异常,而有呼吸道症状组和胸片异常组则分别有5项异常.四组均以DLco、FEF_(25%～75%)和PEF下降的发生率和下降幅度最大.各组FEV_1/EVC均在正常范围内.胸片正常组VC、TLC、FRC和DLco明显高于异常组.结论:SSc肺功能改变与呼吸系统症状和胸片异常改变有关,且早于呼吸系统症状出现和胸片异常改变前.弥散功能障碍和小气道病变是SSc早期肺功能改变.肢端型SSc亦有很高比例的肺功能损害.SSc早期存在代偿性肺气肿.     

Cystic Lung Disease: a Comparison of Cystic Size, as Seen on Expiratory and Inspiratory HRCT Scans

Objective

To determine the effects of respiration on the size of lung cysts by comparing inspiratory and expiratory high-resolution CT (HRCT) scans.

Materials and Methods

The authors evaluated the size of cystic lesions, as seen on paired inspiratory and expiratory HRCT scans, in 54 patients with Langerhans cell histiocytosis (n = 3), pulmonary lymphangiomyomatosis (n = 4), confluent centrilobular emphysema (n = 9), paraseptal emphysema and bullae (n = 16), cystic bronchiectasis (n = 13), and honeycombing (n = 9). Using paired inspiratory and expiratory HRCT scans obtained at the corresponding anatomic level, a total of 270 cystic lesions were selected simultaneously on the basis of five lesions per lung disease. Changes in lung cyst size observed during respiration were assessed by two radiologists. In a limited number of cases (n = 11), pathologic specimens were obtained by open lung biopsy or lobectomy.

Results

All cystic lesions in patients with Langerhans cell histiocytosis, lymphangiomyomatosis, cystic bronchiectasis, honeycombing, and confluent centrilobular emphysema became smaller on expiration, but in two cases of paraseptal emphysema and bullae there was no change.

Conclusion

In cases in which expiratory CT scans indicate that cysts have become smaller, cystic lesions may communicate with the airways. To determine whether, for cysts and cystic lesions, this connection does in fact exist, paired inspiratory and expiratory HRCT scans are necessary.     

Superior vena cava obstruction: Complication of pulmonary artery ectasia in levo-transposition of the great arteries

Obstruction of the superior vena cava developed in a 13-year-old child with levo-transposition of the great arteries and pulmonary artery hypertension. Obstruction was due to extrinsic compression of the superior vena cava by an ectatic main pulmonary artery.     

Accurate estimation of global and regional cardiac function by retrospectively gated multidetector row computed tomography

Retrospective reconstruction of ECG-gated images at different parts of the cardiac cycle allows the assessment of cardiac function by multi-detector row CT (MDCT) at the time of non-invasive coronary imaging. We compared the accuracy of such measurements by MDCT to cine magnetic resonance (MR). Forty patients underwent the assessment of global and regional cardiac function by 16-slice MDCT and cine MR. Left ventricular (LV) end-diastolic and end-systolic volumes estimated by MDCT (134±51 and 67±56 ml) were similar to those by MR (137±57 and 70±60 ml, respectively; both P=NS) and strongly correlated (r=0.92 and r=0.95, respectively; both P<0.001). Consequently, LV ejection fractions by MDCT and MR were also similar (55±21 vs. 56±21%; P=NS) and highly correlated (r=0.95; P<0.001). Regional end-diastolic and end-systolic wall thicknesses by MDCT were highly correlated (r=0.84 and r=0.92, respectively; both P<0.001), but significantly lower than by MR (8.3±1.8 vs. 8.8±1.9 mm and 12.7±3.4 vs. 13.3±3.5 mm, respectively; both P<0.001). Values of regional wall thickening by MDCT and MR were similar (54±30 vs. 51±31%; P=NS) and also correlated well (r=0.91; P<0.001). Retrospectively gated MDCT can accurately estimate LV volumes, EF and regional LV wall thickening compared to cine MR. Grant funding: Dr. Belge was supported by a fellowship of the Fondation Nationale de la Recherche Scientifique of the Belgian government. Dr. Gerber was supported by a grant from the Fondation Nationale de la Recherche Scientifique of the Belgian government (FRSM 3.4557.02).