Use of three-dimensional echocardiography for analysis of outflow obstruction in congenital heart disease

To evaluate the feasibility and accuracy of 3-dimensional (3D) echocardiography in analysis of left and right ventricular outflow tract (LVOT and RVOT) obstruction, 3D echocardiography was performed in 28 patients (age 4 months to 36 years) with outflow tract pathology. Type of lesion and relation to valves were assessed. Length and degree of obstruction were measured. Three-D data sets were adequate for reconstruction in 25 of 28 patients; 47 reconstructions were made. In 13 patients with LVOT obstruction, 3D echocardiography was used to study subvalvular details in 8, valvular in 13, and supravalvular in 1. Four of these 13 patients had complex subaortic obstruction. In 12 patients with RVOT lesions, 3D echocardiography was used to study subvalvular details in 11, valvular in 12, and supravalvular in 2. Three-dimensional reconstructions were suitable for analysis in 100% of subvalvular LVOT, 77% valvular LVOT, 100% supravalvular LVOT, 100% subvalvular RVOT, 50% valvular RVOT, and 50% supravalvular RVOT. Twenty patients underwent operation, and surgical findings served as morphologic control for thirty-four 3D reconstructions (LVOT 17, RVOT 17). Operative findings revealed an accuracy at subvalvular LVOT of 100%, valvular LVOT 90%, supravalvular LVOT 100%, subvalvular RVOT 100%, valvular RVOT 100%, and supravalvular RVOT 100%. Quantitative measurements could adequately be performed. Three-D echocardiography is feasible and accurate for analyzing both outflow tracts of the heart. Particularly, generation of nonconventional horizontal cross sections allows a good definition of extension and severity of lesions.     

Echocardiography in Percutaneous Balloon Mitral Valvuloplasty

Percutaneous balloon valvuloplasty (BV) has been used successfully in recent years for the relief of mitral stenosis, and in many instances, as an alternative to cardiac surgery. This procedure requires precise evaluation of both valve morphology and function for preprocedure decision making and follow-up of patients. Two-dimensional (2-D) echocardiography is a unique, noninvasive tool for evaluating morphologic characteristics of valve, subvalvular apparatus, and valve annular size. Doppler echocardiogarphy provides functional information on transvalvular flow velocity, which can be used to derive pressure gradient across valve and regurgitant flow. Mitral valve area can be either obtained from 2-D echocardiography or derived from Doppler pressure half time. Echocardiography is currently the most widely used technique for assessing results of percutaneous BV. More recently, transesophageal echocardiography (TEE) has been used for the evaluation of patients undergoing percutaneous mitral BV in whom left atrial thrombus is suspected and for the intraoperative monitoring of the valvuloplasty procedure. In this article we discuss the advantages and limitations of both transthoracic echocardiography and TEE, its recent developments in monitoring the procedure, evaluation of immediate results and long term follow-up after the valvuloplasty procedure, and its clinical utility in the selection of patients for percutaneous BV.     

Transesophageal echocardiography in the operating room]

The need to optimize cardiac surgery performance combined with the capability that intraoperative transesophageal echocardiography (ETE) has to evaluate the surgical results in real time, without invading the operative field and with an image quality as good as epicardial echo, have led to the increasing use of this tool in the surgical setting. After describing the historical evolution and defining the leading indications to perform intraoperative echocardiography, the author reports his experience with intraoperative TEE. The echocardiographic evaluation of the surgically repaired mitral valve deserves particular attention as it represents the leading reason to perform intraoperative TEE in his experience. Between January 91 and January 98, 116 intraoperative TEE were performed, most of them (65%) in patients submitted to valvular surgery, particularly for the evaluation of reparative mitral valve surgery results (34%). The results of conservative surgery was considered satisfactory in 33 patients (82%) ad unsatisfactory in six (15%). These patients have had a second run of cardiopulmonary by-pass and a mitral prosthesis was implanted in all of them. Looking ahead, the author concludes with the importance that three-dimensional and myocardial contrast echocardiography will have on broadening the indications to perform intraoperative TEE.     

Utility of three-dimensional transesophageal echocardiography in the diagnosis of valvular perforations

Three-dimensional (3D) transesophageal echocardiographic (TEE) imaging is a relatively new imaging modality that is increasingly being used to characterize a variety of cardiac pathologic features. In the present study, we reviewed the 2-dimensional (2D) and 3D TEE images from our echocardiographic database to identify patients with valve perforations. A review of the 2D TEE images resulted in the identification of 11 valvular perforations (6 aortic valves, 4 mitral valves, and 1 tricuspid valve). A review of the 3D TEE images allowed for the identification of 15 valve perforations (7 aortic valves, 7 mitral valves, and 1 tricuspid valve), including 4 perforations that could not be diagnosed using 2D imaging alone. In conclusion, 3D TEE imaging provided added benefit to traditional 2D TEE imaging because of its ability to provide en face visualization of the cardiac valves, allowing improved identification and precise anatomic localization of the perforation.     

Feasibility of a new generation three-dimensional echocardiography for right ventricular volumetric and functional measurements

Right ventricular (RV) dimensions and function are of diagnostic and prognostic importance in cardiac disease. Because of the peculiar morphology of the right ventricle, 2-dimensional echocardiography has several limitations in RV evaluation. Recently, new 3-dimensional transthoracic echocardiographic software adapted for RV morphology was introduced. The aims of this study were to evaluate the feasibility of 3-dimensional RV analysis in a large population and to compare and correlate 3-dimensional RV data with classic 2-dimensional and Doppler parameters, including tricuspid annular plane systolic excursion and peak systolic velocity on Doppler tissue imaging, RV fractional shortening area, RV stroke volume (by the Doppler method), and pulmonary arterial systolic pressure. Two hundred subjects were studied: 48 normal controls and 152 patients with valvular heart disease (104 patients), idiopathic dilated cardiomyopathy (20 patients), or pulmonary hypertension (28 patients). The mean times for 3-dimensional acquisition and 3-dimensional reconstruction were 3 +/- 1 and 4 +/- 2 minutes, respectively. Imaging quality was good in most cases (85%). The mean RV diastolic and systolic volumes were 103 +/- 38 and 46 +/- 28 ml, respectively. The RV ejection fraction (RVEF) was correlated negatively with pulmonary arterial systolic pressure and positively with tricuspid annular plane systolic excursion, peak systolic velocity, and fractional shortening area. The pathologic group was characterized by larger RV volumes and lower RVEFs. Three-dimensional echocardiography clearly showed that in the pathologic group, patients with pulmonary hypertension had the largest RV volumes and the lowest RVEFs and that those with idiopathic dilated cardiomyopathy were characterized by RVEFs lower than those of patients with valvular disease. In conclusion, this new quantitative 3-dimensional method to assess RV volumes and function is feasible, relatively simple, and not time consuming. Data obtained with 3-dimensional analysis are well correlated with those obtained by 2-dimensional and Doppler methods and can differentiate normal and pathologic subjects.     

Morphologic features of carcinoid heart disease as assessed by three-dimensional transesophageal echocardiography

Background: Carcinoid heart disease (CHD) is a rare cause of valvular heart disease and carries a poor prognosis. CHD has a unique morphology and echocardiographic features that predominantly involve right‐sided valvular structures. The diagnosis of CHD is usually made by two‐dimensional transthoracic echocardiography (TTE). With the superior spatial resolution of real time three‐dimensional transesophageal echocardiography (3DTEE), structural changes that occur in patients with CHD‐associated valvular heart disease can be examined in greater detail. We undertook this study to examine the incremental value of 3DTEE in the diagnosis of CHD. Methods: A total of four patients with CHD underwent TTE, transesophageal echocardiography (TEE), and 3DTEE as part of their routine clinical evaluation. Results: TTE and TEE for all four patients revealed thickened, fibrosed, retracted, and malcoapted tricuspid leaflets with wide‐open tricuspid valve regurgitation. 3DTEE en face imaging of the tricuspid valve demonstrated the characteristic morphologic features of CHD more clearly in all four patients. Conclusions: 3DTEE provides substantial incremental value over TTE in the assessment of characteristic CHD pathology and thus enhances the echocardiographic diagnosis of CHD. (Echocardiography 2010;27:1098‐1105)     

Comparison of magnetic resonance imaging of aortic valve stenosis and aortic root to multimodality imaging for selection of transcatheter aortic valve implantation candidates

The purpose of the present study was to compare the aortic valve area, aortic valve annulus, and aortic root dimensions measured using magnetic resonance imaging (MRI) with catheterization, transthoracic echocardiography (TTE), and transesophageal echocardiography (TEE). An optimal prosthesis--aortic root match is an essential goal when evaluating patients for transcatheter aortic valve implantation. Comparisons between MRI and the other imaging techniques are rare and need validation. In 24 consecutive, high-risk, symptomatic patients with severe aortic stenosis, aortic valve area was prospectively determined using MRI and direct planimetry using three-dimensional TTE and calculated by catheterization using the Gorlin equation and by Doppler echocardiography using the continuity equation. Aortic valve annulus and the aortic root dimensions were prospectively measured using MRI, 2-dimensional TTE, and invasive aortography. In addition, aortic valve annulus was measured using TEE. No differences in aortic valve area were found among MRI, Doppler echocardiography, and 3-dimensional TTE compared with catheterization (p = NS). Invasive angiography underestimated aortic valve annulus compared with MRI (p <0.001), TEE (p <0.001), and 2-dimensional TTE (p <0.001). Two-dimensional TTE tended to underestimate the aortic valve annulus diameters compared to TEE and MRI. In contrast to 2-dimensional TTE, 3 patients had aortic valve annulus beyond the transcatheter aortic valve implantation range using TEE and MRI. In conclusion, MRI planimetry, Doppler, and 3-dimensional TTE provided an accurate estimate of the aortic valve area compared to catheterization. MRI and TEE provided similar and essential assessment of the aortic valve annulus dimensions, especially at the limits of the transcatheter aortic valve implantation range.     

Three-dimensional echocardiographic evaluation of an incidental quadricuspid aortic valve

Background: Quadricuspid aortic valve is one of the rare forms of congenitalcardiac valvular disease. Its diagnosis is often missed, evenwith the transthoracic echocardiogram. Many of these patientsprogress to aortic incompetence later in life requiring surgicalintervention. In addition, quadricuspid aortic valve can beassociated with other congenital cardiac deformities. Henceearly recognition and follow-up is critical in these patients. Case presentation: We report a patient with quadricuspid aortic valve identifiedon intraoperative transesophageal 3-D echocardiography. This66-year-old male presented with the features of congestive heartfailure. The preoperative transthoracic echocardiogram (TTE)disclosed, moderately severe aortic valve insufficiency alongwith severe mitral and tricuspid regurgitation, but failed toreveal the quadricuspid anomaly of the aortic valve. Interestingly,this patient had undergone transthoracic echocardiography ontwo previous occasions during the past seven years for the evaluationof his valvular heart disease, which all failed to documentthis anomaly. Intraoperatively, transesophageal echocardiography(TEE) displayed an aortic valve composed of three medium andone small cusps. Conclusion: Our patient's case demonstrates the usefulness of transesophagealechocardiography in detection of this uncommon congenital malformation.     

Accuracy of 2-dimensional echocardiographic diagnosis of congenitally bicuspid aortic valve: Echocardiographic-anatomic correlation in 115 patients

The preoperative 2-dimensional (2-D) echocardiograms of all patients <50 years of age in whom the aortic valve had been directly inspected by the surgeon or the pathologist or both were reviewed. From June 1977 to June 1981, 283 patients aged ≤50 years had aortic valve surgery at the Mayo Clinic: 115 (aged 1 to 50 years [mean 32]) had 2-D examinations preoperatively. The echocardiograms were reviewed blindly, and the aortic valve structure was categorized as bicuspid, tricuspid, or indeterminate. On the basis of combined surgical and pathologic inspection, 50 aortic valves were con genitally bicuspid, 60 were tricuspid, 4 were unicommissural, and 1 was quadricuspid. By 2-D echocardiography, the number of cusps was indeterminate in 29 patients (25%). When these patients were excluded, the sensitivity, specificity, and diagnostic accuracy of 2-D echocardiography for bicuspid aortic valve were 78, 96, and 93%, respectively. Thus, with adequate 2-D images, echocardiography is a sensitive and highly specific technique for the diagnosis of bicuspid aortic valve.     

Value of intraoperative transesophageal echocardiography in preventing serious complications during valvular surgery. A report of four cases

The value of routine transesophageal echocardiography (TEE) was confirmed by the detection of rare and potentially serious complications in four of 136 patients (2.9%) undergoing valvular surgery. In case 1, one leaflet of a St. Jude Medical (SJM) valve implanted in the mitral position was stuck in the closed position; normal valve function was restored by 90 degrees rotation of the prosthesis. In case 2, moderate regurgitation was observed after mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. The mitral valve was replaced with a SJM valve; regurgitation was proved due to a suture loop jamming. In case 3, perivalvular leakage was detected after aortic valve replacement for infective endocarditis; an additional suture stopped the leakage. In case 4, a foreign body was observed in the left atrium after aortic valve replacement for calcified aortic stenosis. The left atrium was re-opened, and a free-floating portion of the calcified native aortic valve was identified and removed. Routine intraoperative TEE in valve surgery permits the identification and management of potentially serious complications before discontinuing cardiopulmonary bypass.     

Intraoperative transesophageal echocardiography for evaluation of mitral valve repair.

BACKGROUND AND AIM OF THE STUDY: Although mitral valve repair is a well-established procedure, incorrect assessment of the repaired valve may occasionally lead to the need for reoperation. This study was performed to evaluate the accuracy of color Doppler in assessing the competence of the repaired mitral valve. METHODS: Transesophageal echocardiography (TEE) and left ventriculography were each performed in 72 patients to compare the two techniques and a semi-quantitative index derived. Using this relationship, post bypass intraoperative TEE was then performed in 34 patients who underwent mitral valve repair, in order to assess the competence of the repaired valve. RESULTS: Significant differences were apparent in maximal regurgitant mosaic area between angiographic grade 0, and grades 1+ (p = 0.0006), 1+ and 2+ (p < 0.0001) and 2+ and 3+ (p = 0.0010). A maximal regurgitant area < 2 cm2 predicted angiographic grade as 0 (sensitivity 100%, specificity 95%), an area of 2-4 cm2 as 1+ (sensitivity 82%, specificity 100%), an area of 4-7 cm2 as 2+ (sensitivity 78%, specificity 90%), and an area > 7 cm2 as grade 3+ or 4+ (sensitivity 79%, specificity 93%). All 34 patients completed valve repair with the maximal regurgitant mosaic area < 2.5 cm2. Postoperative left ventriculography showed grade +1 in only five patients; four of these completed mitral valve repair with a maximal mosaic area > 2.0 cm2 as assessed by post bypass intraoperative TEE. During follow up, transthoracic echocardiography (TTE) detected recurrent mitral regurgitation which required mitral valve replacement in one patient, and rapid progression of mitral regurgitation in three patients. CONCLUSIONS: It is important that mitral valve repair should be completed with a maximal mosaic area < 2.0 cm2 as assessed by intraoperative TEE, in order to reduce the need for reoperation.     

A unique case of “double‐orifice aortic valve”—comprehensive assessment by 2‐, 3‐dimensional,and color Doppler echocardiography

Transesophageal echocardiography (TEE) is a powerful imaging tool for the comprehensive assessment of valvular structure and function. TEE may be of added benefit when anatomy is difficult to delineate accurately by transthoracic echocardiography. In this article, we present 2‐, 3‐dimensional, and color Doppler TEE images from a male patient with aortic stenosis. A highly unusual and complex pattern of valvular calcification created a functionally “double‐orifice” valve. Such an abnormality may have implications for the accuracy of continuous‐wave Doppler echocardiography, which assumes a single orifice valve in native aortic valves.     

Comparison of accuracy of mitral valve regurgitation volume determined by three-dimensional transesophageal echocardiography versus cardiac magnetic resonance imaging

Direct planimetry of anatomic regurgitation orifice area (AROA) using 3-dimensional transesophageal echocardiography (TEE) has been described. This study sought to (1) compare mitral valve regurgitant volume (RV) derived by AROA using 3-dimensional TEE with RV obtained by cardiac magnetic resonance (CMR) imaging and (2) determine the impact of AROA and flow velocity changes throughout systole on the dynamic variation in mitral regurgitation. In 43 patients (71 ± 11 years old) with mild to severe mitral regurgitation, 3-dimensional TEE and CMR were performed. Mitral valve RV was determined based on (1) AROA at 5 subintervals of systole and analysis of the regurgitant continuous-wave Doppler signal at equal durations of systole, (2) effective regurgitation orifice area (EROA) using the proximal isovelocity surface area method, (3) CMR with subtraction of aortic outflow volume from left ventricular stroke volume. RV calculated by AROA tended to overestimate RV less than RV calculated by EROA compared to RV by CMR (average bias +20 ml, 95% confidence interval [CI] -41 to +81, vs +13 ml, 95% CI -22 to 47). In patients with RV >30 ml by CMR, overestimation of RV using the AROA method was less than using the EROA method (difference in means +18 ml, 95% CI 4 to 32, p <0.001). AROA determined by 3-dimensional TEE varied by only 18% among the 5 subintervals of systole, and the velocity time integral of the subinterval with the highest flow was 120% of the subinterval with the lowest flow. In conclusion, 3-dimensional TEE allows accurate analysis of mitral valve RV. In the clinically relevant group of patients with RV >30 ml as defined by CMR, the AROA method results in less overestimation of RV than the EROA method. Changes in AROA during systole contribute much less to dynamic variation in mitral regurgitation severity than changes in regurgitant flow velocity.     

Comparison of three-dimensional imaging to transesophageal echocardiography for preoperative evaluation in mitral valve prolapse

Transesophageal echocardiography (TEE) is not optimally suited for recognizing which valve segments are involved in type II mitral valve dysfunction. This study was conducted to compare the diagnostic value of TEE and 3-dimensional image reconstruction (3DIR) in the assessment of Carpentier type II mitral valve lesions. In 74 patients (mean age 59+/-13 years) with mitral regurgitation due to type II valve dysfunction, TEE and 3DIR were performed and analyzed by 2 experts before surgical repair. Leaflet scallops and commissures were displayed in short-axis en face and long-axis views. Echocardiographic results were surgically validated. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated, broken down by valve segments and Barlow's disease. Interobserver variability was also determined. Compared with TEE, 3DIR was superior with respect to sensitivity, positive and negative predictive values, and accuracy, although not always significantly (p<0.05). Specificity was higher for P2 lesions. The clearest advantage of 3DIR over TEE was higher sensitivity in commissural and bileaflet defects (p<0.05). Interobserver agreement on 3DIR was stronger than on TEE results (kappa values 0.52 vs 0.82, p<0.0001). There were 16 disagreements (23%) on TEE but only 5 (7%) on 3DIR readings. In conclusion, the more complex the lesion, the more valuable 3DIR is compared with TEE. Before repair, 3DIR is beneficial for the evaluation and classification of the specific pathology in type II mitral valve dysfunction.     

食管超声心动图在重危心脏病人诊断治疗中的价值

目的　为评价食管超声心动图 (TEE)在重危心脏病人诊断治疗中的价值 ,对 3 7例收住监护病房的重症心血管病人进行了经胸超声心动图 (TTE)和TEE检查 ,其中男 2 5例 ,女 1 2例 ,平均年龄57( 1 9～ 85)岁。入选对象包括怀疑夹层动脉瘤 2 3例、心脏瓣膜功能异常 9例、感染性心内膜炎 3例 ,心内分流 2例。结果　所有病人均可耐受TEE检查 ,无并发症发生 ,TEE较TTE可提供更高的阳性诊断结果 ,阳性率分别为 65 0 %和 3 8 0 % ,在怀疑夹层动脉瘤者中 ,TEE检出夹层撕裂膜 1 4例 ;而TTE仅检出 7例 ,且图象欠清 ,检出部位有限。在 4例人工机械瓣膜功能异常者中 ,TEE发现瓣膜部位血栓形成 3例。结论　在对心脏大血管疾病的诊断中 ,TEE阳性诊断率高于TTE ,尤其在怀疑夹层动脉瘤及人工机械瓣膜病变时 ,应行TEE检查。即使在重危病人 ,TEE也是一种安全有效的诊断手段。     

经食管超声心动图在二尖瓣成形术中的应用价值

目的探讨经食管超声心动图在二尖瓣成形术中的应用价值。方法术前18例二尖瓣关闭不全患者均常规经胸超声心动图检查,术中经食管超声心动图监测,并即刻评价二尖瓣成形术的效果。结果本组18例中16例一次性手术实施成功。1例术中监测发现反流2级后再次实施成形后成功,1例术中监测发现反流3级后改行二尖瓣置换术。结论经食管超声心动图在二尖瓣成形术中具有非常重要的临床应用价值。     

Multiplane two-dimensional versus real time three-dimensional transesophageal echocardiography in ischemic mitral regurgitation

Objectives: Intraoperative three‐dimensional (3D) transesophageal echocardiography (TEE) has been suggested to be a valuable technique for the evaluation of the mechanisms of ischemic mitral regurgitation (IMR). Studies comparing multiplane two‐dimensional (2D) with 3D TEE reconstruction of the mitral valve using the new mitral valve quantification (MVQ) software are lacking. We undertook a prospective comparison between multiplane 2D and 3D TEE for the assessment of IMR. Methods: We evaluated echocardiographically 45 patients with IMR who underwent mitral valve surgery in our institution. 2D and 3D TEE examinations followed by a 3D offline assessment of the mitral valve apparatus were performed in all patients. Offline analysis of mitral valve apparatus was conducted with QLAB–MVQ. Results: 3D TEE image acquisitions were performed in a short period of time and were feasible in all patients. Real time 3D TEE imaging was superior to 2D in identifying specific mitral scallops (A1, A3, P1, P3) and commissures. When compared with 2D TEE, 3D offline reconstruction of the mitral valve allows an accurate quantification of the shape and diameters of the mitral annulus. Both approaches provide almost similar values for the tenting area and the coaptation depth. The 3D approach gave the advantage of direct calculation of the leaflets angles, tenting volume, and surface of the leaflets. The interpapillary muscles distance at the level of the papillary muscle head was greater in 2D than in 3D. Conclusions: 3D TEE imaging provides valuable and complementary information to multiplane 2D TEE for the assessment of patients with IMR. (Echocardiography 2011;28:1125‐1132)     

Impressive echocardiographic images of a rare pathology: Aneurysm of the mitral valve – Report of two cases and review of the literature

Aneurysm of the mitral valve (AMV) is rarely reported. The etiology of this unusual pathology is commonly attributed to aortic valve endocarditis (AVE) with aortic regurgitation (AR) or connective tissue disease. We present two recent cases of AMV with good correlation between pre-operative trans-esophageal echocardiography (TEE), intra-operative real-time 3-dimensional echocardiography (RT-3D-Echo) and surgical findings. The importance of diligent surveillance by TEE in patients with AVE for occurrence of AMV is emphasized. The literature on this topic is briefly reviewed.     

Clinical utility of new real time three-dimensional transthoracic echocardiography in assessment of mitral valve prolapse

BACKGROUND: Noninvasive and accurate assessment of mitral valve anatomy has become integral in the presurgical evaluation of patients with mitral valve prolapse (MVP). Recently developed real time three-dimensional (RT3D) ultrasound allows online acquisition, rendering, and can provide accurate information on cardiac structures. We sought to evaluate the feasibility of RT3D for the assessment of MVP segments when compared with transesophageal echocardiography (TEE) and intraoperative findings. METHODS: We examined 42 patients with MVP using RT3D, two-dimensional (2D) transthoracic echocardiography (TTE) and TEE. For RT3D analysis, cropping planes were used to slice the 3D volume on line to visualize the prolapsed segments of the mitral valve leaflets. The mitral valve was divided into six segments based on the American Society of Echocardiography's recommendations. Two experienced cardiologists evaluated echocardiographic images. RESULTS: Adequate RT3D images of the mitral valve were acquired in 40 out of 42 patients. The sensitivity and specificity of RT3D for defining prolapsed segments when compared with TEE were 95% and 99%, respectively (anterior leaflet: 96% and 99%, posterior leaflets: 93% and 100%, respectively). The sensitivity and specificity of TTE were 93% and 97%, respectively (anterior leaflet: 96% and 98%, posterior leaflets: 90% and 97%, respectively). Interobserver agreement for RT3D (Kappa 0.95, 95% confidence interval [CI] 0.91-1.00) was significantly greater than for TTE (Kappa 0.85, 95% CI 0.78-0.93) (P < 0.05). The elapsed time for completion of RT3D (14.4 +/- 2.8 min) was shorter than for TEE (26.4 +/- 4.7 min, P < 0.0001) and TTE (19.0 +/- 3.1 min, P< 0.0001). CONCLUSIONS: RT3D is fast, accurate, and highly reproducible for assessing MVP.