Absolute Myocardial Perfusion in Canines Measured by Using Dual-Bolus First-Pass MR Imaging

Purpose: To examine whether T2* effects reduce the accuracy of arterial input function (AIF) measurement by the dual-sequence method. Materials and Methods:The dual-sequence method obtains a low-resolution AIF image and high-resolution myocardial images in each cycle, with suitable T1 weightings. It was modified to assess T2* effects in the low-resolution AIF image (4.8 ϫ 4.8 ϫ 10 mm voxels, TE ϭ 0.58 msec) by minimizing T1 weighting in that sequence, while the myocardial sequence remained T1-weighted. In 10 patients who underwent perfusion MRI scans (0.5 M Magnevist, 0.1 mmol/kg, 15-ml flush, 7 mL/second right antecubital) the blood signal in the left ventricle (LV) was measured at the bolus peak and compared with the first cycle's fresh magnetization signal. Results:The bolus peak measured 98% Ϯ 4% (mean Ϯ SD, N ϭ 20) of the value before contrast agent arrival. MEASURING MYOCARDIAL PERFUSION requires undistorted arterial input function (AIF) and high signal-to-noise ratio (SNR) myocardial tissue response function measurements. The dual-sequence method (1,4) obtains these measurements in the same cardiac cycle, while the dual-bolus method (2,3) uses separate low-and high-dose first passes for the AIF and myocardial measurements, respectively. The dual-bolus and dual-sequence methods agreed reasonably well in previous in vivo studies (1), and the dual-bolus method has been validated against microspheres as the gold standard (2). ConclusionIn each cardiac cycle, the dual-sequence method (1) acquires a low-resolution image of the left ventricular (LV) blood using a fast (50 msec) sequence with low T1-sensitivity for the AIF, followed by a high-resolution high-T1-sensitivity sequence to acquire images for the myocardial tissue response. The larger voxels of the fast AIF sequence are expected to have more T2* dephasing than those of a typical myocardial perfusion sequence. Larger voxels have more distance over which B0-inhomogeneity may dephase the signal. Conversely, the shorter TE and faster echo sampling of the AIF sequence should reduce T2* effects. It was therefore necessary to test for T2* effects in vivo.The purpose of this work was to examine whether T2* effects in large pixels reduce the accuracy of AIF measurement, which would distort myocardial perfusion measurement by the "dual-sequence" method (1). MATERIALS AND METHODSA Siemens Sonata 1.5T (Numaris 4, VA21) was used with a 12-channel cardiac array coil placed around the patient's chest (six anterior and six posterior elements).In 10 patients referred for assessment of myocardial perfusion, three short-axis myocardial slices were collected on each of 50 cardiac cycles, starting with a breath-hold at end-expiration, imaging the first pass (0.5M Magnevist, 0.1 mmol/kg, and then 15-ml saline flush at 7 mL/second, 18-gauge right antecubital). Adenosine stress (140 g/kg/min) perfusion imaging was performed for clinical examination and the perfusion imaging was repeated at rest after at least 20 minutes. The 50-msec rapid AIF sequence was run at each R-wave w...

supporting

confidence: 56%

T2* effects in the dual‐sequence method for high‐dose first‐pass myocardial perfusion

Gatehouse

Lyne

Smith

et al. 2006

“…PBF and PBV values were calculated for all single-bolus measurements, which means that AIF and tissue signal-time courses were taken from the same datasets for contrast agent doses of 0.5 mL, 1.0 mL, 2.0 mL, and 3.0 mL, respectively. Additionally, PBF and PBV were calculated using the prebolus approach (14,15). The prebolus technique consists of a combination of two measurements.…”

Section: Theorymentioning

confidence: 99%

“…With the application of higher doses, signal saturation occurs, which leads to underestimation of the actual concentration. This problem was investigated by different groups working on contrast-enhanced perfusion quantification with MRI of different tissues, and several techniques have been proposed to overcome this limitation (11)(12)(13)(14)(15). One promising technique is the prebolus (or dual-bolus) approach, which was initially proposed for quantification of myocardial perfusion (14,15).…”

mentioning

confidence: 99%

“…This problem was investigated by different groups working on contrast-enhanced perfusion quantification with MRI of different tissues, and several techniques have been proposed to overcome this limitation (11)(12)(13)(14)(15). One promising technique is the prebolus (or dual-bolus) approach, which was initially proposed for quantification of myocardial perfusion (14,15). The prebolus approach consists of a low-dose measurement for accurate determination of the arterial input function (AIF), followed by a second, higher dose measurement to evaluate the tissue signal.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Quantitative contrast‐enhanced perfusion measurements of the human lung using the prebolus approach

Oechsner

Mühlhäusler

Ritter

et al. 2009

Purpose: To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). Materials and Methods:Eleven volunteers were examined by applying different contrast agent doses (0.5, 1.0, 2.0, and 3.0 mL gadolinium diethylene triamine pentaacetic acid [Gd-DTPA]), using a saturation-recovery (SR) true fast imaging with steady precession (TrueFISP) sequence. PBF and PBV were determined for single bolus and prebolus. Region of interest (ROI) evaluation was performed and parameter maps were calculated. Additionally, cardiac output (CO) and lung volume were determined and GLP was calculated as a contrast agent-independent reference value. Results:The prebolus results showed good agreement with low-dose single-bolus and GLP: PBF (mean Ϯ SD in units of mL/minute/100 mL) ϭ single bolus 190 Ϯ 73 (0.5-mL dose) and 193 Ϯ 63 (1.0-mL dose); prebolus 192 Ϯ 70 (1.0 -2.0-mL dose) and 165 Ϯ 52 (1.0 -3.0-mL dose); GLP (mL/minute/100 mL) ϭ 187 Ϯ 34. Higher single-bolus resulted in overestimated values due to arterial input function (AIF) saturation. Conclusion:The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps. THE PERFUSION OF THE HUMAN LUNG, together with ventilation, plays a decisive role for efficient blood oxygenation. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) offers a radiation-free noninvasive technique for spatial analysis of pulmonary perfusion (1-4). Based on the indicator dilution theory (5), DCE-MRI enables the quantification of pulmonary perfusion (6). Several investigations deal with technical improvements and physiological aspects of lung perfusion measurements (7-10). A major challenge of quantitative DCE-MRI is the choice of appropriate contrast agent doses. Typically, perfusion quantification is performed assuming a linear relationship between the local contrast agent concentration and the MR signal intensity. This assumption is only valid within a limited range. With the application of higher doses, signal saturation occurs, which leads to underestimation of the actual concentration. This problem was investigated by different groups working on contrast-enhanced perfusion quantification with MRI of different tissues, and several techniques have been proposed to overcome this limitation (11)(12)(13)(14)(15). One promising technique is the prebolus (or dual-bolus) approach, which was initially proposed for quantification of myocardial perfusion (14,15). The prebolus approach consists of a low-dose measurement for accurate determination of the arterial input function (AIF), followed by a second, higher dose measurement to evaluate the tissue signal.It has been established from quantification of m...

“…The large-contrast bolus that is used to determine the myocardial response provides adequate signal to noise ratio. The implementation of the prebolus has shown to provide absolute perfusion values comparable to perfusion values determined by microspheres in animals (5,6) and positron emission tomography (PET) in healthy volunteers (7). Kurita et al (11) showed that regional myocardial perfusion reserve (MPR) determined by using dual-bolus MR-MPI correlated well to coronary flow reserve by intracoronary Doppler flow wire in patients with suspected coronary artery disease (CAD).…”

mentioning

confidence: 99%

Comparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery disease

Groothuis

Kremers

Beek

et al. 2010

Purpose: To investigate the incremental diagnostic value of dual-bolus over single-contrast-bolus first pass magnetic resonance myocardial perfusion imaging (MR-MPI) for detection of significant coronary artery disease (CAD). Materials and Methods:Patients (n ¼ 49) with suspected CAD underwent first pass adenosine stress and rest MR-MPI and invasive coronary angiography (CA). Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was injected with a prebolus (1 mL) and a large bolus (0.1 mmol/kg). For the single-bolus technique, the arterial input function (AIF) was obtained from the large-contrast bolus. For the dual-bolus technique, the AIF was reconstructed from the prebolus. Absolute myocardial perfusion was calculated by Fermi-model constrained deconvolution. Receiver operating characteristic (ROC) analysis was used to investigate diagnostic accuracy of MR myocardial perfusion imaging for detection of significant CAD on CA at vessel-based analysis. Results:The area under the curve (AUC) of the minimal stress perfusion value for the detection of significant CAD using the single-bolus and dual-bolus technique was 0.85 6 0.04 (95% confidence interval [CI], 0.77-0.93) and 0.77 6 0.05 (95% CI, 0.67-0.86), respectively. Conclusion:In this study the dual-bolus technique had no incremental diagnostic value over single-bolus technique for detection of significant CAD with the used contrast concentrations.