Archive for the year 2009

Nov200923

1

Detection and Characteristics of Microvascular Obstruction in Reperfused Acute Myocardial Infarction using an Optimized Protocol for Contrast-Enhanced Cardiovascular Magnetic Resonance Imaging

Eur Radiol. 2009; 19(12):2904-2912

Bekkers SC, Backes WH, Kim RJ, Snoep G, Gorgels AP, Passos VL, Waltenberger J, Crijns HJ, Schalla S

OBJECTIVES: Several cardiovascular magnetic resonance imaging (CMR) techniques are used to detect microvascular obstruction (MVO) after acute myocardial infarction (AMI).

METHODS: To determine the prevalence of MVO and gain more insight into the dynamic changes in appearance of MVO, we studied 84 consecutive patients with a reperfused AMI on average 5 and 104 days after admission, using an optimised single breath-hold 3D inversion recovery gradient echo pulse sequence (IR-GRE) protocol.

RESULTS: Early MVO (2 min post-contrast) was detected in 53 patients (63%) and late MVO (10 min post-contrast) in 45 patients (54%; p = 0.008). The extent of MVO decreased from early to late imaging (4.3 +/- 3.2% vs. 1.8 +/- 1.8%, p < 0.001) and showed a heterogeneous pattern. At baseline, patients without MVO (early and late) had a higher left ventricular ejection fraction (LVEF) than patients with persistent late MVO (56 +/- 7% vs. 48 +/- 7%, p < 0.001) and LVEF was intermediate in patients with early MVO but late MVO disappearance (54 +/- 6%). During follow-up, LVEF improved in all three subgroups but remained intermediate in patients with late MVO disappearance.

CONCLUSIONS: This optimised single breath-hold 3D IR-GRE technique for imaging MVO early and late after contrast administration is fast, accurate and allows detection of patients with intermediate remodelling at follow-up.

PMID: 19588152

Nov200922

2

MRI and CT Appearances of Cardiac Tumours in Adults

Clin Radiol. 2009; 64(12):1214-1230

Hoey ET, Mankad K, Puppala S, Gopalan D, Sivananthan MU

OBJECTIVES: Primary cardiac tumours are rare, and metastases to the heart are much more frequent. Myxoma is the commonest benign primary tumour and sarcomas account for the majority of malignant lesions. Clinical manifestations are diverse, non-specific, and governed by the location, size, and aggressiveness.

METHODS: Imaging plays a central role in their evaluation, and familiarity with characteristic features is essential to generate a meaningful differential diagnosis.

RESULTS: Cardiac magnetic resonance imaging (MRI) has become the reference technique for evaluation of a suspected cardiac mass. Computed tomography (CT) provides complementary information and, with the advent of electrocardiographic gating, has become a powerful tool in its own right for cardiac morphological assessment.

CONCLUSIONS: This paper reviews the MRI and CT features of primary and secondary cardiac malignancy. Important differential considerations and potential diagnostic pitfalls are also highlighted.

PMID: 19913133

Nov200922

2

Relation Between Visceral Fat and Coronary Artery Disease Evaluated by Multidetector Computed Tomography

Atherosclerosis. 2009; 120(21):2029-2032

Marques MD, Santos RD, Parga JR, Rocha-Filho JA, Quaglia LA, Miname MH, Avila LF

OBJECTIVES: Visceral abdominal fat has been associated to cardiovascular risk factors and coronary artery disease (CAD). Computed tomography (CT) coronary angiography is an emerging technology allowing detection of both obstructive and nonobstructive CAD adding information to clinical risk stratification. The aim of this study was to evaluate the association between CAD and adiposity measurements assessed clinically and by CT.

METHODS: We prospectively evaluated 125 consecutive subjects (57% men, age 56.0+/-12 years) referred to perform CT angiography. Clinical and laboratory variables were determined and CT angiography and abdominal CT were performed in a 64-slice scanner. CAD was defined as any plaque calcified or not detected by CT angiography. Visceral and subcutaneous adiposity areas were determined at different intervertebral levels.

RESULTS: CT angiography detected CAD in 70 (56%) subjects, and no association was found with usual anthropometric adiposity measurements (waist and hip circumferences and body mass index). Otherwise, CT visceral fat areas (VFA) were significantly related to CAD. VFA T12-L1 values >145cm(2) had an odds ratio of 2.85 (95% CI 1.30-6.26) and VFA L4-L5 >150cm(2) had a 2.87-fold (95% CI 1.31-6.30) CAD risk.

CONCLUSIONS: The multivariate analysis determined age and VFA T12-L1 as the only independent variables associated to CAD. Visceral fat assessed by CT is an independent marker of CAD determined by CT angiography.

PMID: 19922936

Nov200921

1

Dual source CT Coronary Angiography in Severely Obese Patients: Trading Off Temporal Resolution and Image Noise

Invest Radiol. 2009; 44(11):720-727

Leschka S, Stinn B, Schmid F, Schultes B, Thurnheer M, Baumueller S, Stolzmann P, Scheffel H, Flohr TG, Wildermuth S, Alkadhi H

OBJECTIVES: To assess in severely obese patients the subjective and objective image quality parameters and to estimate the radiation dose of dual-source computed tomography coronary angiography (CTCA), using 3 different protocols.

METHODS: Dual-source CTCA was performed in 60 patients (30 women; mean age 58 +/- 7 years) suffering from obesity class II or higher (body mass index [BMI] >35 kg/sq m). Twenty patients were examined with a standard CTCA protocol at 120 kV/350 mAs (protocol A), 20 patients with a CTCA protocol at 140 kV/350 mAs (protocol B), and 20 patients at 140 kV/350 mAs with a dedicated obesity protocol (protocol C), that allows the additional data sampling by expanding the data acquisition for each tube from a quarter to a half rotation, permitting to trade off temporal resolution and image noise. Two blinded observers independently assessed the image quality of each coronary segment, using a 4-point scale (1: excellent-4: nondiagnostic) and measured the different image parameters (image noise, signal-to-noise ratio [SNR], and contrast-to-noise ratio [CNR]). Radiation dose estimates were calculated.

RESULTS: The average BMI was 46.3 +/- 8.3 kg/sq m (range, 36.8-69.6 kg/sq m). Subjective image quality (1.55 +/- 0.73) was significantly better in protocol C when compared with protocol A (2.46 +/- 0.76; P < 0.01) and protocol B (2.12 +/- 0.87; P < 0.017). There was a significantly lower rate of coronary artery segments with nondiagnostic image quality when using the obesity protocol C (1.5%; 4/262) compared with that obtained when using protocol A (7.8%; 22/280; P < 0.01) and protocol B (4.4%; 12/275; P < 0.017). Image noise was significantly lower in protocol C (31.8 +/- 5.0 HU) when compared with group A (43.5 +/- 4.7 HU; P < 0.001) and B (36.8 +/- 5.5 HU; P < 0.01). SNR and CNR were significantly higher in group C (13.8 +/- 2.4 and 23.1 +/- 2.8) compared with group A (10.6 +/- 1.7 and 15.1 +/- 3.2; each P < 0.001) and group B (12.0 +/- 2.0 and 18.8 +/- 3.1; each P < 0.01). The estimated effective radiation dose of the obesity protocol C (15.6 +/- 0.9 mSv) was significantly higher when compared with that in protocol A (10.1 +/- 0.8 mSv; P < 0.01), but not significantly different from that in protocol B (13.3 +/- 0.8 mSv; P = 0.022).

CONCLUSIONS: Use of an obesity protocol in dual-source CTCA in severely obese patients significantly improves image quality, but goes along with a higher radiation dose.

PMID: 19809341

Nov200921

1

Outcomes of Patients With Acute Type A Aortic Intramural Hematoma

Circulation. 2009; 120(21):2029-2032

Song JK, Yim JH, Ahn JM, Kim DH, Kang JW, Lee TY, Song JM, Choo SJ, Kang DH, Chung CH, Lee JW, Lim TH

OBJECTIVES: The proper treatment option for patients with type A intramural hematoma (IMH), a variant form of classic aortic dissection (AD), remains controversial. We assessed the outcome of our institutional policy of urgent surgery for unstable patients and initial medical treatment for stable patients with surgery in cases with complications.

METHODS: Among 357 consecutive patients with type A acute aortic syndrome, 101 (28.3%) had IMH and 256 had AD. Urgent operations were performed in 224 patients with AD (87.5%) and 16 with unstable IMH (15.8%; P<0.001). The remaining 85 stable IMH patients received initial medical treatment, and adverse clinical events developed in 31 patients (36.5%) within 6 months, which included development of AD (n=25), delayed surgery (n=25), or death (n=6).

RESULTS: Initial aorta diameter and hematoma thickness were independent predictors for development of these events, and the best cutoff values were 55 and 16 mm, respectively. The overall hospital mortality was lower in IMH patients than in AD patients (7.9% [8/101] versus 17.2% [44/256]; P=0.0296) and was comparable to that of surgically treated AD patients (7.9% versus 10.7% [24/224]; P=0.56). The 1-, 2-, and 3-year survival rates of IMH patients were 87.6+/-3.6%, 84.9+/-3.7%, and 83.1+/-4.1%, respectively. There was no statistical difference of overall survival rates between patients with IMH and surgically treated AD patients (P=0.787).

CONCLUSIONS: The clinical outcome of IMH patients receiving treatment by our policy was comparable to that of surgically treated AD patients. However, adverse clinical events were not uncommon with medical treatment alone, and initial aorta diameter and hematoma thickness may identify patients who might benefit from urgent surgery.

PMID: 19901188

Nov200919

2

New Reconstruction Algorithm Allows Shortened Acquisition Time for Myocardial Perfusion SPECT

Eur J Nucl Med Mol Imaging. 2009; 49(S1):72

Valenta I, Treyer V, Husmann L, Gaemperli O, Schindler MJ, Herzog BA, Veit-Heibach P, Buechel RR, Nkoulou R, Pazhenkottil AP, Kaufmann PA

OBJECTIVES: : Shortening scan time and/or reducing radiation dose at maintained image quality are the main issues of the current research in radionuclide myocardial perfusion imaging (MPI). We aimed to validate a new iterative reconstruction (IR) algorithm for SPECT MPI allowing shortened acquisition time (HALF time) while maintaining image quality vs. standard full time acquisition (FULL time).

METHODS: In this study, 50 patients, referred for evaluation of known or suspected coronary artery disease by SPECT MPI using 99mTc-Tetrofosmin, underwent 1-day adenosine stress 300 MBq/rest 900 MBq protocol with standard (stress 15 min/rest 15 min FULL time) immediately followed by short emission scan (stress 9 min/rest 7 min HALF time) on a Ventri SPECT camera (GE Healthcare). FULL time scans were processed with IR, short scans were additionally processed with a recently developed software algorithm for HALF time emission scans. All reconstructions were subsequently analyzed using commercially available software (QPS/QGS, Cedars Medical Sinai) with/without X-ray based attenuation correction (AC). Uptake values (percent of maximum) were compared by regression and Bland-Altman (BA) analysis in a 20-segment model.

RESULTS: HALF scans yielded a 96% readout and 100% clinical diagnosis concordance compared to FULL. Correlation for uptake in each segment (n = 1,000) was r = 0.87at stress (p < 0.001) and r = 0.89 at rest (p < 0.001) with respective BA limits of agreement of -11% to 10% and -12% to 11%. After AC similar correlation (r = 0.82, rest; r = 0.80, stress, both p < 0.001) and BA limits were found (-12% to 10%; -13% to 12%).

CONCLUSION: With the new IR algorithm, SPECT MPI can be acquired at half of the scan time without compromising image quality, resulting in an excellent agreement with FULL time scans regarding to uptake and clinical conclusion.

PMID: 19921186

Nov200918

1

Influence of Myocardial Fibrosis on Left Ventricular Diastolic Function

Circ Cardiovasc Imaging. 2009; 2(6):437-443

Moreo A, Ambrosio G, De Chiara B, Pu M, Tran T, Mauri F, Raman SV

OBJECTIVES: Fibrosis is a common end point of many pathological processes affecting the myocardium and may alter myocardial relaxation properties. By measuring myocardial fibrosis with cardiac magnetic resonance and diastolic function with Doppler echocardiography, we sought to define the influence of fibrosis on left ventricular diastolic function.

METHODS: Two hundred four eligible subjects from 252 consecutive subjects undergoing late postgadolinium myocardial enhancement (LGE) cardiac magnetic resonance and Doppler echocardiography were investigated.

RESULTS: Subjects with normal diastolic function exhibited no or minimal fibrosis (median LGE score, 0; interquartile range, 0 to 0). In contrast, the majority of patients with cardiomyopathy (regardless of underlying cause) had abnormal diastolic function indices and substantial fibrosis (median LGE score, 3; interquartile range, 0 to 6.25). Prevalence of LGE positivity by diastolic filling pattern was 13% in normal, 48% in impaired relaxation, 78% in pseudonormal, and 87% in restrictive filling (P<0.0001). Similarly, LGE score was significantly higher in patients with deceleration time <150 ms (P<0.012), and it progressively increased with increasing left ventricular filling pressure estimated by tissue Doppler imaging–derived E/E’ (P<0.0001). After multivariate analysis, LGE remained significantly correlated with degree of diastolic dysfunction (P=0.0001).

CONCLUSIONS: Severity of myocardial fibrosis by LGE significantly correlates with the degree of diastolic dysfunction in a broad range of cardiac conditions. Noninvasive assessment of myocardial fibrosis may provide valuable insights into the pathophysiology of left ventricular diastolic function and therapeutic response.

PMID: pending

Nov200917

3

Intracoronary Optical Coherence Tomography: A Comprehensive Review

J Am Coll Cardiol Intv. 2009; 2(11):1035-1046

Bezerra HG, Costa MA, Guagliumi G, Rollins AM, Simon DI

OBJECTIVES: Cardiovascular optical coherence tomography (OCT) is a catheter-based invasive imaging system.

METHODS: Using light rather than ultrasound, OCT produces high-resolution in vivo images of coronary arteries and deployed stents. This comprehensive review will assist practicing interventional cardiologists in understanding the technical aspects of OCT based upon the physics of light and will also highlight the emerging research and clinical applications of OCT.

RESULTS: Semi-automated imaging analyses of OCT systems permit accurate measurements of luminal architecture and provide insights regarding stent apposition, overlap, neointimal thickening, and, in the case of bioabsorbable stents, information regarding the time course of stent dissolution. T

CONCLUSIONS: The advantages and limitations of this new imaging modality will be discussed with emphasis on key physical and technical aspects of intracoronary image acquisition, current applications, definitions, pitfalls, and future directions.

PMID: 19926041

Nov200914

1

Multicenter Investigation Comparing a Highly Efficient Half-Time Stress-Only Attenuation Correction Approach Against Standard Rest-Stress Tc-99m SPECT Imaging

J Nucl Cardiol. 2009; 16(5):726-735

Bateman TM, Heller GV, McGhie AI, Courter SA, Golub RA, Case JA, Cullom SJ

OBJECTIVES: New iterative algorithms for scatter compensation (SC), noise suppression, and depth-dependent collimator resolution (RR) can shorten rest and stress SPECT acquisitions by 50% while maintaining quality and accuracy equivalent to conventional scans. Full-time stress-only myocardial perfusion SPECT is accurate and efficient when combined with line-source attenuation correction (LSAC). We investigated the potential for half-time stress-only LSAC-SPECT by comparing this to conventional rest/stress SPECT in patients imaged for suspected CAD at three different centers.

METHODS: One hundred and ten patients (58% men, 53% exercise) had 64 projection rest/stress Tc-99m ECG-gated SPECT with simultaneous Gd-153 LSAC: 18 had < 5% CAD likelihood and 92 had coronary angiography. The stress scans were retrospectively ‘stripped’ to create equally spaced 32 projection “half-time” (HT) scans for the emission and transmission (TX) projections. Astonish (Philips, Milpitas, CA) processing with AC, SC, and RR was applied to the HT data with the HT TX maps reconstructed using a Bayesian iterative method. The conventional rest/stress image sets processed using filtered back projection and without AC and the HT-AC stress-only images were interpreted in random sequence by consensus of two readers blinded to clinical information in separate reading sessions.

RESULTS: Comparing rest/stress FBP and HT-LSAC, stress perfusion quality was excellent/good in 82 and 89% (P = .13); interpretive certainty (definitely normal or abnormal) was 88 and 95% (P = .14); sensitivity was 77 and 83% (P = .38); specificity was 67 and 71% (P = .65); normalcy was 94 and 100% (P = 1.0); SSS for CAD pts was 7.4 vs 7.8 and for non-CAD pts was 0.7 vs 0 (P = .44 and .16, respectively). Mean stress LVEF was 60% in both groups.

CONCLUSIONS: Stress-only imaging with HT-LSAC using the Astonish acquisition/processing method provides results equivalent to conventional rest/stress scanning. This new approach has the potential to significantly improve operational efficiency without sacrificing accuracy.

PMID: 19548048

Nov200914

1

Real-Time Three-Dimensional Transoesophageal Echocardiography in the Assessment of Aortic Valve Stenosis

Eur J Echocardiogr. 2009; 1(154):1093

de la Morena G, Saura D, Oliva MJ, Soria F, González J, García M, Moreno V, Bonaque JC, Valdés M

OBJECTIVES: To determine the feasibility of real-time three-dimensional transoesophageal echocardiography (3D-TOE) in the evaluation of aortic valve stenosis, to study its reliability, and to test the concordance of this new method when compared with transthoracic two-dimensional echocardiography (2D-TTE) as the diagnostic standard.

METHODS: Fifty-nine consecutive patients with moderate-to-severe aortic valve stenosis were assessed by means of 2D-TTE and 3D-TOE by independent blinded observers.

RESULTS: Aortic valve planimetry was possible in 94.9% of patients. Inter-observer intraclass correlation coefficients (ICC) were 0.892 (CI 95% 0.818-0.936; P < 0.001), and 0.871 (CI 95% 0.780-0.925; P < 0.001) for 2D-TTE and 3D-TOE, respectively. Bland-Altman plot showed a mean difference in aortic valve area (AVA) of 0.040 cm(2), with 2D-TTE yielding larger values than 3D-TOE. ICC of both methods was 0.724 (CI 95% 0.530-0.839; P < 0.001).

CONCLUSIONS: Assessment of AVA by means of 3D-TOE is feasible in most patients with aortic valve stenosis. Reliability of the measurement is good. However, there is some disagreement with standard 2D-TTE that needs further investigation.

PMID: 19805413

Nov200913

2

Comparison of Multidetector-Row Computed Tomography to Echocardiography and Fluoroscopy for Evaluation of Patients with Mechanical Prosthetic Valve Obstruction

Am J Cardiol. 2009; 104(8):1128-1134

Symersky P, Budde RP, de Mol BA, Prokop M

OBJECTIVES: For evaluation of prosthetic heart valve obstruction echocardiography and fluoroscopy provide primarily functional information, but may not unequivocally establish the cause of dysfunction. Our objective was to evaluate whether multidetector-row computed tomographic (MDCT) imaging could detect the morphologic substrate for such functional abnormalities.

METHODS: Thirteen patients with 15 prosthetic valves, in whom prosthetic valve obstruction was suspected from echocardiography or fluoroscopy, but no sufficient cause could be found, underwent electrocardiographically gated multidetector-row computed tomography. MDCT data were retrospectively reconstructed at every 10% of the electrocardiographic interval and analyzed using multiplanar reformatting in anatomically adapted planes. MDCT images were evaluated for morphologic prosthetic and periprosthetic abnormalities.

RESULTS: Results could be compared to intraoperative findings or autopsy in 7 patients. Multidetector-row computed tomography disclosed a morphologic substrate for obstruction in 8 of 13 patients. MDCT findings compatible with obstruction were confirmed at surgery or autopsy in 6 patients. In a seventh patient, incomplete leaflet closure found with multidetector-row computed tomography was confirmed at surgery. The most commonly identified causes for obstruction were subprosthetic tissue (6 patients) and abnormal anatomic orientation (3 patients). Despite an indication for surgery, 2 patients were not operated on due to recurrent bacteremias and prohibitive co-morbidity. Multidetector-row computed tomography detected leaflet motion restriction in 7 patients compared to 4 by fluoroscopy. Confirmation of leaflet restriction was available in 5 patients. Multidetector-row computed tomography missed a periprosthetic leak.

CONCLUSIONS: In conclusion, this initial experience demonstrates that multidetector-row computed tomography can identify causes of prosthetic valve obstruction that constitute indications for surgery, but are missed at echocardiography or fluoroscopy.

PMID: 19801036

Nov200912

3

Quantification of Functional Mitral Regurgitation by Real-Time 3D Echocardiography: Comparison With 3D Velocity-Encoded Cardiac Magnetic Resonance

JACC Cardiovasc Imaging. 2009; 2(11):1245-1252

Marsan NA, Westenberg JJ, Ypenburg C, Delgado V, van Bommel RJ, Roes S, Tops LF, van der Geest RJ, de Roos A, Reiber JC, Schalij MJ, Bax JJ

OBJECTIVES: The aim of this study was to evaluate feasibility and accuracy of real-time 3-dimensional (3D) echocardiography for quantification of mitral regurgitation (MR), in a head-to-head comparison with velocity-encoded cardiac magnetic resonance (VE-CMR). Background: Accurate grading of MR severity is crucial for appropriate patient management but remains challenging. VE-CMR with 3D three-directionalacquisition has been recently proposed as the reference method.

METHODS: A total of 64 patients with functional MR were included. A VE-CMR acquisition was applied to quantify mitral regurgitant volume (Rvol). Color Doppler 3D echocardiography was applied for direct measurement, in “en face” view, of mitral effective regurgitant orifice area (EROA); Rvol was subsequently calculated as EROA multiplied by the velocity-time integral of the regurgitant jet on the continuous-wave Doppler. To assess the relative potential error of the conventional approach, color Doppler 2-dimensional (2D) echocardiography was performed: vena contracta width was measured in the 4-chamber view and EROA calculated as circular (EROA-4CH); EROA was also calculated as elliptical (EROA-elliptical), measuring vena contracta also in the 2-chamber view. From these 2D measurements of EROA, the Rvols were also calculated.

RESULTS: The EROA measured by 3D echocardiography was significantly higher than EROA-4CH (p < 0.001) and EROA-elliptical (p < 0.001), with a significant bias between these measurements (0.10 cm2 and 0.06 cm2, respectively). Rvol measured by 3D echocardiography showed excellent correlation with Rvol measured by CMR (r = 0.94), without a significant difference between these techniques (mean difference = –0.08 ml/beat). Conversely, 2D echocardiographic approach from the 4-chamber view significantly underestimated Rvol (p = 0.006) as compared with CMR (mean difference = 2.9 ml/beat). The 2D elliptical approach demonstrated a better agreement with CMR (mean difference = –1.6 ml/beat, p = 0.04).

CONCLUSIONS: Quantification of EROA and Rvol of functional MR with 3D echocardiography is feasible and accurate as compared with VE-CMR; the currently recommended 2D echocardiographic approach significantly underestimates both EROA and Rvol.

PMID:

Nov200912

2

Stent Gap by 64-Detector Computed Tomographic Angiography: Relationship to In-Stent Restenosis, Fracture, and Overlap Failure

J Am Coll Cardiol. 2009; 54(21):1949-1959

Hecht HS, Polena S, Jelnin V, Jimenez M, Bhatti T, Parikh M, Panagopoulos G, Roubin G

OBJECTIVES: The goal of this study was to define the frequency of stent gaps by 64-detector computed tomographic angiography (CTA) and their relation to in-stent restenosis (ISR), stent fracture (SF), and overlap failure (OF). Background: SF defined by catheter angiography or intravascular ultrasound has been implicated in ISR.

METHODS: A total of 292 consecutive patients, with 613 stents, who underwent CTA were evaluated for stent gaps associated with decreased Hounsfield units. Correlations with catheter coronary angiography (CCA) were available in 143 patients with 384 stents.

RESULTS: Stent gaps were noted in 16.9% by CTA and 1.0% by CCA. ISR by CCA was noted in 46.1% of the stent gaps (p < 0.001) as determined by CCA, and stent gaps by CTA accounted for 27.8% of the total ISR (p < 0.001). In univariate analysis, stent diameter ≥3 mm was the only CCA characteristic significantly associated with stent gaps (p = 0.002), but was not a significant predictor by multivariate analysis. Bifurcation stents, underlying calcification, stent type, location, post-dilation, and overlapping stents were not observed to be predisposing factors. Excessive tortuosity and lack of conformability were not associated with stent gaps; however, their frequency was insufficient to permit meaningful analysis.

CONCLUSIONS: Stent gap by CTA: 1) is associated with 28% of ISR, and ISR is found in 46% of stent gaps; 2) is associated with ≥3 mm stents by univariate (p = 0.002) but not by multivariate analysis; 3) is infrequently noted on catheter angiography; and 4) most likely represents SF in the setting of a single stent, and may represent SF or OF in overlapping stents.

PMID: 19909876

Nov200912

4

Coronary Computed Tomography Angiography with a Consistent Dose Below 1 mSv using Prospectively Electrocardiogram-Triggered High-Pitch Spiral Acquisition

Eur Heart J. 2009; 1(1):470

Achenbach S, Marwan M, Ropers D, Schepis T, Pflederer T, Anders K, Kuettner A, Daniel WG, Uder M, Lell MM

OBJECTIVES: We evaluated the feasibility and image quality of a new scan mode for coronary computed tomography angiography (CTA) with an effective dose of less than 1 mSv.

METHODS: In 50 consecutive patients (body weight <100 kg, sinus rhythm <60 b.p.m. after pre-medication, coronary CTA was performed using a dual-source CT system with 2 x 128 x 0.6 mm collimation, 0.28 s rotation time, a pitch of 3.2 or 3.4, 100 kV tube voltage and current of 320 mA s. Data acquisition was prospectively triggered at 60% of the R-R interval and completed within one cardiac cycle. Image quality was evaluated using a four-point scale (1 = absence of any artefacts to 4 = uninterpretable).

RESULTS: In all 50 patients, imaging was successful. Mean duration of data acquisition was 258 +/- 20 ms. Mean dose-length product was 62 +/- 5 mGy cm, the effective dose was 0.87 +/- 0.07 mSv (0.78-0.99 mSv). Of the 742 coronary artery segments, 94% had an image quality score of 1, 5.0% a score of 2, 0.9% a score of 3, and 4 segments (0.5%) were “uninterpretable.”

CONCLUSIONS: In non-obese patients with a low and stable heart rate, prospectively ECG-triggered high-pitch spiral coronary CTA provides excellent image quality at a consistent dose below 1.0 mSv.

PMID: 19897497

Nov200912

2

Interventricular Mechanical Dyssynchrony: Quantification with Velocity-encoded MR Imaging

Radiology. 2009; 253(2):364-371

Muellerleile K, Baholli L, Groth M, Barmeyer AA, Koopmann K, Ventura R, Koester R, Adam G, Willems S, Lund GK

OBJECTIVES: To evaluate the performance of velocity-encoded (VENC) magnetic resonance (MR) imaging, as compared with pulsed-wave echocardiography (PW-ECHO), in the quantification of interventricular mechanical dyssynchrony (IVMD) as a predictor of response to cardiac resynchronization therapy (CRT).

METHODS:  The study was approved by the local ethics committee, and all patients provided written informed consent. The study involved the examination of 45 patients (nine women, 36 men; median age, 60 years; interquartile age range, 47–69 years) with New York Heart Association class 2.0–3.0 heart failure and a reduced left ventricular ejection fraction (median, 25%; interquartile range, 21%–32%), with (n = 25) or without (n = 20) left bundle branch block. Aortic and pulmonary flow curves were constructed by using VENC MR imaging and PW-ECHO. IVMD was defined as the difference between the onset of aortic flow and the onset of pulmonary flow. Intraclass correlation coefficient, Spearman correlation coefficient, Bland-Altman, and Cohen κ analyses were used to assess agreement between observers and methods.

RESULTS: Inter- and intraobserver agreement regarding VENC MR imaging IVMD measurements was very good (intraclass r = 0.96, P < .001; mean bias, −3 msec ± 11 [standard deviation] and 0 msec ± 10, respectively). A strong correlation (Spearman r = 0.92, P < .001) and strong agreement (mean difference, −6 msec ± 16) were found between VENC MR imaging and PW-ECHO in the quantification of IVMD. Agreement between VENC MR imaging and PW-ECHO in the identification of potential responders to CRT was excellent (Cohen κ = 0.94).

CONCLUSIONS: VENC MR measurements of IVMD are equivalent to PW-ECHO measurements and can be used to identify potential responders to CRT.

PMID: 19703849

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