The International Journal of Cardiovascular Imaging

Chopard, Romain; Boussel, Loic; Motreff, Pascal; Rioufol, Gilles; Tabib, Alain; Douek, Philippe; Meyronet, David; Revel, Didier; Finet, Gérard

doi: 10.1007/s10554-009-9562-ypmid: 20052618

The present study investigated whether IVUS could serve as a reliable reference in validating MDCT characterization of coronary plaque against a histological gold standard. Twenty-one specimens were postmortem human coronary arteries. Coronary cross-sections were imaged by 40 MHz IVUS and by 64-slice MDCT and characterized histologically as presenting calcified, fibrous or lipid-rich plaques. Plaque composition was analyzed visually and intra-plaque MDCT attenuation was measured in Hounsfield Units (HU). 83 atherosclerotic plaques were identified. IVUS failed to characterize calcified plaque accurately, with a positive predictive value (ppv) of 75% versus 100% for MDCT. Lipid-rich plaque was even less accurately characterized, with ppv of 60 and 68% for IVUS and MDCT respectively. Mean MDCT attenuation was 966 ± 473 HU for calcified plaque, 83 ± 35 HU for fibrous plaque and 70.92 HU ± 41 HU for lipid-rich plaque. No significant difference in mean MDCT attenuation was found between fibrous and lipid-rich plaques (P = 0.276). In vivo validation of MDCT against an IVUS reference thus appears to be an unsuitable and unreliable approach: 40 MHz IVUS suffers from acoustic ambiguities in plaque characterization, and 64-slice MDCT fails to analyze plaque morphology and components accurately.

Wann, Samuel

doi: 10.1007/s10554-010-9611-6pmid: 20352343

Shin, Eun-Seok; Garcia-Garcia, Hector; Serruys, Patrick

doi: 10.1007/s10554-009-9567-6pmid: 20063068

Although previous intravascular ultrasound (IVUS) radiofrequency-based analysis data showed acceptable reproducibility for plaque composition, measurements are not easily obtained, particularly that of lumen contour, because of the limited IVUS resolution. The purpose of this study was to compare a new measurement method (Shin’s method) and the conventional measurement method for necrotic core and calcium content in atherosclerotic lesions using Virtual Histology-intravascular ultrasound (VH-IVUS). Fifty-seven patients with unstable angina who underwent elective percutaneous coronary intervention were included. Shin’s method focuses on catheter contour, instead of lumen contour, and vessel contour. Patients ages ranged from 46 to 88 years, and 34 were men. A total of 1,401 frames from 59 culprit lesions were assessed. There were no significant differences in the mean area and volume of necrotic core and dense calcium between the two methods. Correlation coefficients (R) were ≥0.99 for all above mentioned parameters (P < 0.001). Between methods, the absolute differences in mean area and volume of necrotic core were 0.02 ± 0.02 mm² and 0.34 ± 0.29 mm³, respectively, while for mean area and volume of dense calcium, the absolute differences were 0.04 ± 0.07 mm² and 0.36 ± 0.52 mm³, respectively. The reproducibility of Shin’s method was excellent. For area of the necrotic core and dense calcium, the means of the differences between the two measurements were nearly zero, and the reproducibility coefficients were within 1% of the means of the two measurements. Mean analysis time for both measurements was 26.8 ± 6.7 min/segment in the conventional method and 3.3 ± 0.6 min/segment in Shin’s method. Shin’s method for measurement of necrotic core and dense calcium using VH-IVUS demonstrated a good correlation with the conventional method and excellent reproducibility. Also, Shin’s method required a significantly shorter analysis time than the conventional method. Therefore, Shin’s method could replace the conventional method for necrotic core and calcium measurement in atherosclerotic lesions, and it might be useful in the catheterization laboratory for online clinical decision.

Bilge, Ahmet; Atilgan, Dursun; Onur, Imran; Pamukcu, Burak; Ozcan, Mustafa; Adalet, Kâmil

doi: 10.1007/s10554-010-9589-0pmid: 20111906

Longitudinal myocardial function (LMF) may be impaired while systolic function is still normal. We investigated relationship between LMF and hypertensive organ damage in newly diagnosed stage I hypertensive patients. A total of 57 patient with never treated stage I hypertension and 48 matched healthy control subject were enrolled in the study. Conventional 2-D, Doppler and tissue wave Doppler imaging (TDI) echocardiography were used. LMF was evaluated by the septal and lateral strain (S) and strain rate (SR) measurements. Hypertensive complications were evaluated by the urine microalbumin levels and retinal examination. A multivariate regression analysis was perfomed to assess the relation between the variables. Ejection fraction, mid-wall fractional shortenning, systolic movement rates (TDs) in TDI were similar both in hypertensive and control groups. In patients with left ventricular hypertrophy, septal TDs (7.29 ± 1.28 vs. 8.06 ± 1.19 cm, P = 0.03), lateral TDs (8.46 ± 1.83 vs. 9.87 ± 2.42 cm, P = 0.01) and lateral S (−13.02 ± 7.83 vs. −18.86 ± 8.60%, P = 0.01) values were significantly lower. Septal S (−13.67 ± 3.52 vs. −19.09 ± 5.96%, P < 0.01) and SR (−0.83 ± 0.29 vs. −1.22 ± 0.28 1/S, P < 0.01) were significantly decreased in hypertensive patients with microalbuminuria. Septal S value was also significantly decreased in patients with retinopathy (−14.76 ± 5.55 vs. −20.20 ± 5.44%, P = 0.01). Multivariate analysis showed that only septal and lateral S values were independent factors for the retinopathy and left ventricular hypertrophy, respectively. In hypertensive patients, LMF established by the measurement of S and SR, might be impaired and also related with end organ damage while global circumferential function is preserved.

Aypar, Ebru; Alehan, Dursun; Hazırolan, Tuncay; Gümrük, Fatma

doi: 10.1007/s10554-010-9591-6pmid: 20127175

Tissue Doppler imaging (TDI) can detect myocardial dysfunction related to iron load in patients with beta-thalassemia major (TM). We aimed to assess the efficacy of pulsed-wave TDI (PW-TDI) in predicting myocardial iron load in patients with TM using T2* magnetic resonance (MR) as the gold-standard non-invasive diagnostic test. 33 asymptomatic TM patients, mean aged 18 ± 6 years (6–31) with normal left ventricular (LV) global systolic function were evaluated by conventional echocardiography and PW-TDI. Results were compared with 20 age and sex-matched controls. TDI measures included myocardial systolic (Sm), early (Em) and late (Am) diastolic velocities at basal and middle segments of septal and lateral LV wall. Myocardial iron deposition were measured in 29/33 patients by T2* MR. TM patients were also subgrouped according to those with iron load (T2* ≤ 20 ms) and those without (T2* > 20 ms). Mean T2* was 12.3 ± 7.8 ms (4–31.3). Abnormal myocardial iron load (T2* < 20 ms) was found in 25/29 (86%) patients. The following TDI measures were lower in patients than in controls: basal septal Em (P < 0.001) and Am (P < 0.05), mid-septal Am (P < 0.05), mid-lateral LV wall Sm (P < 0.05) and Am (P < 0.05). Regional myocardial dysfunction were more prominent in patients with T2* ≤ 20 ms. Mid-septal Sm and Em significantly correlated with mid-septal T2*(r = 0.44, P = 0.023 and r = 0.54, P = 0.004, respectively). The PW-TDI parameters and the cut-off values for predicting presence of myocardial iron load were determined. PW-TDI technique was found both sensitive and specific in predicting presence of myocardial iron load in TM patients with normal LV global systolic function. Therefore, it can be used for screening of TM patients.

Boehm, Johannes; Haas, Felix; Bauernschmitt, Robert; Wagenpfeil, Stefan; Voss, Bernhard; Schwaiger, Markus; Lange, Rüdiger

doi: 10.1007/s10554-010-9585-4pmid: 20091350

In patients with ischemic cardiomyopathy, coronary artery bypass grafting (CABG) offers an important therapeutic option but is still associated with high perioperative mortality. Although previous studies suggest a benefit from revascularization for patients with defined viability by a non-invasive technique, the role of viability assessment to determine suitability for revascularization in patients with ischemic cardiomyopathy has not yet been defined. This study evaluates the hypothesis that the use of PET imaging in the decision-making process for CABG will improve postoperative patient survival. We reviewed 476 patients with ischemic cardiomyopathy (LV ejection fraction ≤0.35) who were considered candidates for CABG between 1994 and 2004 on the basis of clinical presentation and angiographic data. In a Standard Care Group, 298 patients underwent CABG. In a second PET-assisted management group of 178 patients, 152 patients underwent CABG (PET-CABG) and 26 patients were excluded from CABG because of lack of viability (PET-Alternatives). Primary endpoint was postoperative survival. There were two in hospital deaths in the PET-CABG (1.3%) and 30 (10.1%) in the Standard Care Group (P = 0.018). The survival rate after 1, 5 and 9.3 years was 92.0, 73.3 and 54.2% in the PET-CABG and 88.9, 62.2 and 35.5% in the Standard Care Group, respectively (P = 0.005). Cox-regression analysis revealed a significant influence on long-term survival of patient selection by viability assessment via PET (P = 0.008), of LV-function (P = 0.017), and age >70 (P = 0.016). Preoperative assessment of myocardial viability via PET identifies patients, who will benefit most from CABG.

te Boekhorst, Bernard; Cramer, Maarten; Pasterkamp, Gerard; Echteld, Cees; Doevendans, Pieter

doi: 10.1007/s10554-009-9565-8pmid: 20112134

Atherosclerotic plaque disruption accounts for the major part of cardiovascular mortality and the risk of disruption appears to depend on plaque composition. Carotid plaques in patients, scheduled for endarterectomy, have been successfully characterised with MRI. MRI has the advantage of combining information about morphology and function. Unfortunately, the tortuosity and size of the coronary arteries, and the respiratory and cardiac motion hinder the in vivo characterisation of human coronary plaque. In addition to plaque composition several molecular markers of the different processes involved in atherosclerosis, such as integrins, matrix metalloproteinases and fibrin seem to correlate with risk of plaque rupture and clinical outcome. These molecular markers can be targeted with antibodies coupled to carriers, which are loaded with gadolinium for detection (molecular MRI). Several cellular/molecular MRI studies in animal models and some in human patients have been conducted with varying levels of success. The advent of clinical high field magnets, the development of contrast agent carriers with high relaxivity and the development of relatively new MR contrast techniques are promising in the field of plaque imaging. Future MRI studies will have to focus on the molecular target of the atherosclerotic process, which has the highest prognostic value with regard to acute coronary syndromes and on the most suitable contrast agent to visualize that target.

te Boekhorst, Bernard; Cramer, Maarten-Jan; Pasterkamp, Gerard; Echteld, Cees; Doevendans, Pieter

doi: 10.1007/s10554-009-9566-7pmid: 20058083

Atherosclerotic plaque disruption accounts for the major part of cardiovascular mortality and the risk of disruption appears to depend on plaque composition. Carotid plaques in patients, scheduled for endarterectomy, have been successfully characterised with MRI. MRI has the advantage of combining information about morphology and function. Unfortunately, the tortuosity and size of the coronary arteries, and the respiratory and cardiac motion hinder the in vivo characterisation of human coronary plaque. In addition to plaque composition several molecular markers of the different processes involved in atherosclerosis, such as integrins, matrix metalloproteinases and fibrin seem to correlate with risk of plaque rupture and clinical outcome. These molecular markers can be targeted with antibodies coupled to carriers, which are loaded with gadolinium for detection (molecular MRI). Several cellular/molecular MRI studies in animal models and some in human patients have been conducted with varying levels of success. The advent of clinical high field magnets, the development of contrast agent carriers with high relaxivity and the development of relatively new MR contrast techniques appear to be promising in the field of plaque imaging. Future MRI studies will have to focus on the molecular target of the atherosclerotic process, which has the highest prognostic value with regard to acute coronary syndromes and on the most suitable contrast agent to visualize that target.

Brumback, Lyndia; Kronmal, Richard; Heckbert, Susan; Ni, Hanyu; Hundley, W.; Lima, João; Bluemke, David

doi: 10.1007/s10554-010-9584-5pmid: 20107905

Methods to index left ventricular (LV) mass, measured by cardiovascular magnetic resonance (CMR), for body size have not been investigated. The purposes of this study were to develop allometric indices for LV mass measured by CMR and compare estimates of the prevalence and predictive value of LV hypertrophy defined by a new allometric height-weight index, LV mass/body surface area (BSA), height indices (a new allometric height index; and previously derived indices from echocardiographic measurements: LV mass/height2, LV mass/height2.7), and non-indexed LV mass. 5,004 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with CMR measurements of LV mass and no clinical cardiovascular disease at baseline were followed for a median of 4.1 years. The new indices and limits for hypertrophy (95th percentile) were derived from 822 normal-weight, normotensive, non-diabetic MESA participants. 107 events (coronary heart disease or stroke) were observed. The estimated prevalence of hypertrophy at baseline and hazard ratio for event associated with hypertrophy were 8% and 2.4 with the new allometric height-weight index, 11% and 2.2 with LV mass/BSA, 23–24% and 2.0–2.1 with height indices, and 20% and 1.7 with non-indexed LV mass. A statistically significant difference was detected between the hazard ratios based on the new height-weight index and non-indexed LV mass. The prevalence of hypertrophy is higher for indices that do not account for weight. The predictive value of hypertrophy is significantly better with the new allometric height-weight index than with non-indexed LV mass and may be better than indices without weight.

Wall, E.; Siebelink, H.; Bax, J.

doi: 10.1007/s10554-010-9602-7pmid: 20213471