P846, a new gadolinium based low diffusion magnetic resonance contrast agent,in characterizing occlusive infarcts,reperfused ischemic myocardium and reperfused infarcts in rats

OBJECT: This study has two objectives: (1) to compare the kinetics of low diffusion P846 with Gd-DOTA using inversion recovery echo planar (IR-EPI) magnetic resonance (MR) imaging and (2) to determine the potential of P846 in defining myocardial viability in hearts subjected to various injuries using T1-weighted spin echo (T1-SE). MATERIALS AND METHODS: Rats were subjected to (1) occlusive infarcts (n = 16), (2) reperfused ischemic injuries (n = 8) or (3) reperfused infarcts (n = 16). A dose of 0.05 mmol/kg P846 was compared to 0.1 mmol/kg Gd-DOTA. IR-EPI and T1-SE images were obtained during 60 min. T(1), DeltaR(1) and DeltaR(1) ratio were measured on IR-EPI. Infarct extents were evaluated on T1-SE and compared with histochemical staining. RESULTS: Blood DeltaR(1) was higher at 5 min after P846 (6.36 +/- 0.32 s(-1)) than after Gd-DOTA (1.30 +/- 0.14 s(-1); P < 0.001). With P846, occlusive infarcts appeared as a hypoenhanced region surrounded by a hyperenhanced rim that lasted for 60 min. The increase in the DeltaR(1) ratio value was slower after P846 than with Gd-DOTA in the reperfused infarcts, suggesting low diffusion/convection of P846. Gd-DOTA homogenously enhanced both occlusive and reperfused infarcts at 30 min. CONCLUSION: P846 provides better contrast and extended discrimination between occlusive and reperfused infarcts compared with Gd-DOTA. The gadolinium dose could be reduced with P846.     

Intravascular contrast agent <Emphasis Type="Italic">T1</Emphasis> shortening: fast <Emphasis Type="Italic">T1</Emphasis> relaxometry in a carotid volunteer study

OBJECTIVE: To measure the T1 times in blood after the administration of the intravascular contrast agent gadofosveset trisodium in humans. MATERIALS AND METHODS: In a pilot study for parameter optimization, the T1-shortening induced by the injection of a single dose (0.03 mmol/kg body weight) of the MR contrast agent Vasovist (Bayer Schering Pharma AG) was measured at B (0) = 1.5 T as a function of time. In four sessions, T1 measurements were performed in the carotid vein of 9 volunteers up to 30 min after injection. T1 times were measured using a segmented saturation recovery turboFLASH (SSRTFL) pulse sequence with 7 different saturation recovery delay times in a total acquisition time of 20 s. RESULTS: The SSRTFL measurements showed T1 times of about 100 ms immediately after injection, which gradually increased to 175 ms at 30 min. The time curve of the R1 = 1/T1 averaged over all volunteers could be described with an exponential decay with a time constant T = 330 +/- 65 s and an amplitude DeltaR1 = 4.1 +/- 0.3 s(-1), and a constant offset of R1(0) = 5.7 +/- 0.2 s(-1). Mean relaxation values are in excellent agreement with theoretical predictions. CONCLUSION: An analytical expression for the initial T1-shortening of Vasovist was derived which can now be used for optimization of the pulse sequence parameters in clinical studies.     

Absolute cerebral blood flow measured by dynamic susceptibility contrast MRI: a direct comparison with Xe-133 SPECT

Absolute regional cerebral blood flow (CBF) was measured in ten healthy volunteers, using both dynamic susceptibility-contrast (DSC) magnetic resonance imaging (MRI) and Xe-133 SPECT within 4 h. After i.v. injection of Gd-DTPA-BMA (0.3 mmol/kg b.w.), the bolus was monitored with a Simultaneous Dual FLASH pulse sequence (1.5 s/image), providing one slice through brain tissue and a second slice through the carotid artery. Concentration C(t) is proportional to -(1/TE) ln[S(t)/S(0)] was related to CBF as C(t) = CBF [AIF(t) x R(t)], where AIF is the arterial input function and R(t) is the residue function. A singular-value-decomposition-based deconvolution technique was used for retrieval of R(t). Absolute CBF was given by Zierler's area-to-height relation and the central volume principle. For elimination of large vessels (ELV), all MRI-based CBF values exceeding 2.5 times the mean CBF value of the slice were excluded. A correction for partial-volume effects (CPVE) in the artery used for AIF monitoring was based on registration of signal in a phantom with tubes of various diameters (1.5-6.5 mm), providing an individual concentration correction factor applied to AIF data registered in vivo. In the Xe-133 SPECT investigation, 3,000-4,000 MBq of Xe-133 was administered intravenously, and CBF was calculated using the Kanno Lassen algorithm. When ELV and CPVE were applied, DSC-MRI showed average CBF values from the entire slice of 43 +/- 10 ml/(min 100 g) (small-artery AIF) and 48 +/- 17 ml/(min 100 g) (carotid-artery AIF) (mean +/- S.D., n = 10). The corresponding Xe-133-SPECT-based CBF was 33 +/- 6 ml/(min 100 g) (n = 10). The relationships of CBF(MRI) versus CBF(SPECT) showed good linear correlation (r = 0.74-0.83).     

Magnetic resonance imaging at 1.5 T with immunospecific contrast agent in vitro and in vivo in a xenotransplant model

Object: Demonstrating the feasibility of magnetic resonance imaging (MRI) at 1.5 T of ultrasmall particle iron oxide (USPIO)-antibody bound to tumor cells in vitro and in a murine xenotransplant model. Methods: Human D430B cells or Raji Burkitt lymphoma cells were incubated in vitro with different amounts of commercially available USPIO-anti-CD20 antibodies and cell pellets were stratified in a test tube. For in vivo studies, D430B cells and Raji lymphoma cells were inoculated subcutaneously in immunodeficient mice. MRI at 1.5 T was performed with T1-weighted three-dimensional fast field echo sequences (17/4.6/13°) and T2-weighted three-dimensional fast-field echo sequences (50/12/7°). For in vivo studies MRI was performed before and 24 h after USPIO-anti-CD20 administration. Results: USPIO-anti-CD20-treated D430B cells, showed a dose-dependent decrease in signal intensity (SI) on T2*-weighted images and SI enhancement on T1-weighted images in vitro. Raji cells showed lower SI changes, in accordance to the fivefold lower expression of CD20 on Raji with respect to D430B cells. In vivo 24 h after USPIO-anti-CD20 administration, both tumors showed an inhomogeneous decrease of SI on T2*-weighted images and SI enhancement on T1-weighted images. Conclusions: MRI at 1.5 T is able to detect USPIO-antibody conjugates targeting a tumor-associated antigen in vitro and in vivo.     

In vivo quantitative MRI: T1 and T2 measurements of the human brain at 0.064 T

Objective

To measure healthy brain \({T}_{1}\) and \({T}_{2}\) relaxation times at 0.064 T.

Materials and methods

\({T}_{1}\) and \({T}_{2}\) relaxation times were measured in vivo for 10 healthy volunteers using a 0.064 T magnetic resonance imaging (MRI) system and for 10 test samples on both the MRI and a separate 0.064 T nuclear magnetic resonance (NMR) system. In vivo \({T}_{1}\) and \({T}_{2}\) values are reported for white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) for automatic segmentation regions and manual regions of interest (ROIs).

Results

\({T}_{1}\) sample measurements on the MRI system were within 10% of the NMR measurement for 9 samples, and one sample was within 11%. Eight \({T}_{2}\) sample MRI measurements were within 25% of the NMR measurement, and the two longest \({T}_{2}\) samples had more than 25% variation. Automatic segmentations generally resulted in larger \({T}_{1}\) and \({T}_{2}\) estimates than manual ROIs.

Discussion

\({T}_{1}\) and \({T}_{2}\) times for brain tissue were measured at 0.064 T. Test samples demonstrated accuracy in WM and GM ranges of values but underestimated long \({T}_{2}\) in the CSF range. This work contributes to measuring quantitative MRI properties of the human body at a range of field strengths.

     

Operator dependency of arterial input function in dynamic contrast-enhanced MRI

Objective

To investigate the effect of inter-operator variability in arterial input function (AIF) definition on kinetic parameter estimates (KPEs) from dynamic contrast-enhanced (DCE) MRI in patients with high-grade gliomas.

Methods

The study included 118 DCE series from 23 patients. AIFs were measured by three domain experts (DEs), and a population AIF (pop-AIF) was constructed from the measured AIFs. The DE-AIFs, pop-AIF and AUC-normalized DE-AIFs were used for pharmacokinetic analysis with the extended Tofts model. AIF-dependence of KPEs was assessed by intraclass correlation coefficient (ICC) analysis, and the impact on relative longitudinal change in K^trans was assessed by Fleiss’ kappa (κ).

Results

There was a moderate to substantial agreement (ICC 0.51–0.76) between KPEs when using DE-AIFs, while AUC-normalized AIFs yielded ICC 0.77–0.95 for K^trans, k_ep and v_e and ICC 0.70 for v_p. Inclusion of the pop-AIF did not reduce agreement. Agreement in relative longitudinal change in K^trans was moderate (κ = 0.591) using DE-AIFs, while AUC-normalized AIFs gave substantial (κ = 0.809) agreement.

Discussion

AUC-normalized AIFs can reduce the variation in kinetic parameter results originating from operator input. The pop-AIF presented in this work may be applied in absence of a satisfactory measurement.

     

Magnetic resonance imaging in patients with granulomatosis with polyangiitis (Wegener’s) and subglottic stenosis

Objective

To evaluate the ability of MRI to detect subglottic stenosis and to differentiate between active and inactive subglottic inflammation in patients with granulomatosis with polyangiitis (GPA).

Materials and methods

MRI studies of the larynx of 18 GPA patients with suspected SGS were included. The MRI protocol included T1- and T2-weighted and STIR-sequences, dynamic contrast enhancement (DCE) and diffusion weighted imaging (DWI). Two independent observers reviewed the MR images. SGS were identified and quantified, inflammatory activity was assessed using edema imaging, DCE and DWI. Final MRI diagnoses were compared to the clinical, laryngoscopic and histopathologic results.

Results

MRI confirmed SGS in all GPA patients with significant narrowing of the airway lumen and thickening of subglottic wall. Assessing the subglottic inflammatory activity, MRI showed a sensitivity of 87.5 % and a specificity of 60.0 %. Interrater agreement was κ = 0.769. Of the different MR technical approaches tested, edema imaging was most sensitive and specific. DWI led to significant differences in the apparent diffusion coefficient between active and inactive subglottic inflammation. No significant differences were found with DCE imaging.

Conclusion

MR imaging has shown the ability to detect and grade SGS in patients with GPA. It non-invasively assesses the status of inflammatory activity utilizing edema sensitive sequences and DWI.     

Characterization of pheochromocytomas using quantitati analysis of the parameter T2 of the mass (T2-QMRI)

The usefullness of MR imaging in the characterization of pheochromocytomas was evaluated in 9 patients with 13 pheochromocytomas and 1 paraganglioma. In two patients the tumors were multiple and in one, extra-adrenal. Two patients conformed to MEN2 syndrome. Adrenal masses were characterized using several parameters: (a) visual inspection of the signal intensities in T1-, T2-, and Gd-DTPA-enhanced T1-weighted images; (b) observed signal intensity and observed signal intensity ratios (adrenal mass/liver, adrenal mass/retroperitoneal fat and adrenal mass/ subcutaneous fat) in the T2-weighted images; (c) calculated T2 relaxation times and calculated T2 relaxation time ratios (adrenal mass/liver, adrenal mass/retroperitoneal fat and adrenal mass/subcutaneous fat) of the adrenal masses.All pheochromocytomas had a T2 relaxation time greater than 82 ms with a maximum value of 134.3 ms. These values were calculated using T2 quantitative analysis methods based on in-house designed mathematical routines (T2-QMRI). The signal intensities of the tumor on T2-weighted spin-echo images were extremely high.As a conclusion of this preliminary report it is postulated that T2 quantitative MRI examination (T2-QMRI) is an accurate method for the diagnosis and characterization of pheochromocytomas because it gives positive diagnostic results whether the pheochromocytoma is secreting or nonfunctioning. It can also detect extra-adrenal pheochromocytomas (paragangliomas). Comparative studies with other adrenal tumors is essential to assess accuracy of this method for characterizing these tumors.Address for correspondence: Areteion University Hospital, Radiology Department, VasSofias 76 st, 11528 Athens, Greece. Additional reprints of this chapter may be obtained from the Reprints Department, Chapman & Hall, One Venn Plaza, New York, NY 10119.     

On the correlation between T<Subscript>2</Subscript> and tissue diffusion coefficients in exercised muscle: quantitative measurements at 3T within the tibialis anterior

PURPOSE: To assess the transverse relaxation time T(2) and diffusion coefficient D before and following exercise in the tibialis anterior muscle and determine whether T(2) and D values were correlated. METHODS: Measurements of T(2) and D were performed at 3 T within axial slices through the calf muscles of six healthy volunteers at 95 s intervals before and for 10-12 min after a dorsiflexion exercise to exhaustion. RESULTS: The mean +/- standard deviation (SD) of T(2) and D before exercise were 32 +/- 1.55 ms and 1.52 +/- 0.15 mum(2)/ms, and after exercise were 43 +/- 2.5 ms and 1.72 +/- 0.13 mum(2)/ms, respectively. The mean +/- SD inter-individual recovery times of the % change in T(2) and D after exercise were 7.9 +/- 4.2 and 10.9 +/- 7.0 min, respectively. The T(2) and D values showed a significant correlation throughout the experiments (r (2) = 0.45). CONCLUSIONS: The increase in T(2) of skeletal muscle after exercise is correlated with the increase of the diffusion coefficient D and the recovery times appear similar, indicating that any model used to explain T(2) increases with exercise must also account for increased diffusion coefficients.     

In vivo chlorine and sodium MRI of rat brain at 21.1 T

Object

MR imaging of low-gamma nuclei at the ultrahigh magnetic field of 21.1 T provides a new opportunity for understanding a variety of biological processes. Among these, chlorine and sodium are attracting attention for their involvement in brain function and cancer development.

Materials and methods

MRI of ³⁵Cl and ²³Na were performed and relaxation times were measured in vivo in normal rat (n = 3) and in rat with glioma (n = 3) at 21.1 T. The concentrations of both nuclei were evaluated using the center-out back-projection method.

Results

T ₁ relaxation curve of chlorine in normal rat head was fitted by bi-exponential function (T _1a = 4.8 ms (0.7) T _1b = 24.4 ± 7 ms (0.3) and compared with sodium (T ₁ = 41.4 ms). Free induction decays (FID) of chlorine and sodium in vivo were bi-exponential with similar rapidly decaying components of $ T_{{2{\text{a}}}}^{*} = 0.4 $  ms and $ T_{{2{\text{a}}}}^{*} = 0.53 $  ms, respectively. Effects of small acquisition matrix and bi-exponential FIDs were assessed for quantification of chlorine (33.2 mM) and sodium (44.4 mM) in rat brain.

Conclusion

The study modeled a dramatic effect of the bi-exponential decay on MRI results. The revealed increased chlorine concentration in glioma (~1.5 times) relative to a normal brain correlates with the hypothesis asserting the importance of chlorine for tumor progression.     

A novel framework for evaluating the image accuracy of dynamic MRI and the application on accelerated breast DCE MRI

Objective

To develop a novel framework for evaluating the accuracy of quantitative analysis on dynamic contrast-enhanced (DCE) MRI with a specific combination of imaging technique, scanning parameters, and scanner and software performance and to test this framework with breast DCE MRI with Time-resolved angiography WIth Stochastic Trajectories (TWIST).

Materials and methods

Realistic breast tumor phantoms were 3D printed as cavities and filled with solutions of MR contrast agent. Full k-space raw data of individual tumor phantoms and a uniform background phantom were acquired. DCE raw data were simulated by sorting the raw data according to TWIST view order and scaling the raw data according to the enhancement based on pharmaco-kinetic (PK) models. The measured spatial and temporal characteristics from the images reconstructed using the scanner software were compared with the original PK model (ground truth).

Results

Images could be reconstructed using the manufacturer’s platform with the modified ‘raw data.’ Compared with the ‘ground truth,’ the RMS error in all images was <10% in most cases. With increasing view-sharing acceleration, the error of the initial uptake slope decreased while the error of peak enhancement increased. Deviations of PK parameters varied with the type of enhancement.

Conclusion

A new framework has been developed and tested to more realistically evaluate the quantitative measurement errors caused by a combination of the imaging technique, parameters and scanner and software performance in DCE-MRI.

     

Measurements of T1 and T2 relaxation times of colon cancer metastases in rat liver at 7 T

The purpose of this study was to investigate the magnetic resonance imaging (MRI) characteristics of colon cancer metastases in rat liver at 7 T. A dedicated RF microstrip coil of novel design was built in order to increase the signal-to-noise ratio and, in combination with respiratory triggering, to minimize motion artifacts. T₁- and T₂-weighted MR imaging was performed to follow tumor growth. T₁-weighted images provided a good anatomical delineation of the liver structure, while the best contrast between metastases and normal liver tissue was achieved with T₂-weighted images.Measurements of T₁ and T₂ relaxation times were performed with inversion recovery FLASH and Carr–Purcell–Meiboom–Gill and inversion recovery FLASH imaging sequences, respectively, for quantitative MR characterization of metastases. Both the T₁ and T₂ of the metastases were significantly higher than those of normal liver tissue. Further, an increase in the T₁ relaxation time of the metastases was observed with tumor growth. These findings suggest that quantitative in vivo MR characterization provides information on tumor development and possibly response to therapy, though additional studies are needed to elucidate the correlation between the changes in relaxation times and tumor microenvironment.     

Segmentation and quantification of adipose tissue by magnetic resonance imaging

In this brief review, introductory concepts in animal and human adipose tissue segmentation using proton magnetic resonance imaging (MRI) and computed tomography are summarized in the context of obesity research. Adipose tissue segmentation and quantification using spin relaxation-based (e.g., T1-weighted, T2-weighted), relaxometry-based (e.g., T1-, T2-, T2*-mapping), chemical-shift selective, and chemical-shift encoded water–fat MRI pulse sequences are briefly discussed. The continuing interest to classify subcutaneous and visceral adipose tissue depots into smaller sub-depot compartments is mentioned. The use of a single slice, a stack of slices across a limited anatomical region, or a whole body protocol is considered. Common image post-processing steps and emerging atlas-based automated segmentation techniques are noted. Finally, the article identifies some directions of future research, including a discussion on the growing topic of brown adipose tissue and related segmentation considerations.     

Variable echo time imaging for detecting the short T2* components of the sciatic nerve: a validation study

Objective

The aim of this study was to develop and validate an MRI protocol based on a variable echo time (vTE) sensitive to the short T2* components of the sciatic nerve.

Materials and methods

15 healthy subjects (M/F: 9/6; age: 21–62) were scanned at 3T targeting the sciatic nerve at the thigh bilaterally, using a dual echo variable echo time (vTE) sequence (based on a spoiled gradient echo acquisition) with echo times of 0.98/5.37 ms. Apparent T2* (aT2*) values of the sciatic nerves were calculated with a mono-exponential fit and used for data comparison.

Results

There were no significant differences in aT2* related to side, sex, age, and BMI, even though small differences for side were reported. Good-to-excellent repeatability and reproducibility were found for geometry of ROIs (Dice indices: intra-rater 0.68–0.7; inter-rater 0.70–0.72) and the related aT2* measures (intra-inter reader ICC 0.95–0.97; 0.66–0.85) from two different operators. Side-related signal-to-noise-ratio non-significant differences were reported, while contrast-to-noise-ratio measures were excellent both for side and echo.

Discussion

Our study introduces a novel MR sequence sensitive to the short T2* components of the sciatic nerve and may be used for the study of peripheral nerve disorders.

     

Acoustic noise reduction in a 4 T MRI scanner

High-field, high-speed magnetic resonance imaging (MRI) can generate high levels of noise. There is ongoing concern in the medical and imaging research communities regarding the detrimental effects of high acoustic levels on auditory function, patient anxiety, verbal communication between patients and health care workers and ultimately MR image quality. In order to effectively suppress the noise levels inside MRI scanners, the sound field needs to be accurately measured and characterized. This paper presents the results of measurements of the sound radiation from a gradient coil cylinder within a 4 T MRI scanner under a variety of conditions. These measurement results show: (1) that noise levels can be significantly reduced through the use of an appropriately designed passive acoustic liner; and (2) the true noise levels that are experienced by patients during echo planar imaging.     

Acoustic noise reduction in a 4 T MRI scanner.

High-field, high-speed magnetic resonance imaging (MRI) can generate high levels of noise. There is ongoing concern in the medical and imaging research communities regarding the detrimental effects of high acoustic levels on auditory function, patient anxiety, verbal communication between patients and health care workers and ultimately MR image quality. In order to effectively suppress the noise levels inside MRI scanners, the sound field needs to be accurately measured and characterized. This paper presents the results of measurements of the sound radiation from a gradient coil cylinder within a 4 T MRI scanner under a variety of conditions. These measurement results show: (1) that noise levels can be significantly reduced through the use of an appropriately designed passive acoustic liner; and (2) the true noise levels that are experienced by patients during echo planar imaging.     

(SmCO_7)_(100-x)(Cr_3C_2)_x(x=O～7)熔淬薄带的结构与磁性能

采用熔淬法制备(SmCo7)100-x(Cr3C2)x(x=0～7)合金薄带。研究了Cr3C2添加量对合金相结构、微观组织和磁性能的影响。结果表明,淬速为20m/s时,(SmCo7)100-x(Cr3C2)x熔淬带的矫顽力随Cr3C2含量的增加而增大;剩磁先随x的增大而增高,在x=2时达最大值,然后随x的进一步增大而急剧降低。当熔淬速为20m/s时,(SmCo7)100-x(Cr3C2)x形成了1:7主相结构,同时还有少量的2:17H相和2:17R相。随Cr3C2含量的增加,2:17H相逐渐转变为2:17R相和2:7相。在高Cr3C2含量的合金中出现了含有Cr、Co、C的非磁性晶间相,该相通过抑制主相晶粒的长大及对畴壁的钉扎来提高材料的矫顽力。(SmCo7)93(Cr3C2)7合金在淬速40m/s时形成了非晶结构。该非晶合金在650℃保温6min后获得了远高于相同成分淬态合金的磁性能,Hci=635.4kA/m,Br=0.58T。     

Pseudo-T2 mapping for normalization of T2-weighted prostate MRI

Magnetic Resonance Materials in Physics, Biology and Medicine - Signal intensity normalization is necessary to reduce heterogeneity in T2-weighted (T2W) magnetic resonance imaging (MRI) for...     

High-resolution magnetic resonance imaging of iron-labeled myoblasts using a standard 1.5-T clinical scanner

Myoblast transplantation is a promising means of restoring cardiac function in infarcted areas. For optimization of transplant protocols, tracking the location and fate of the injected cells is necessary. An attractive imaging modality for this is magnetic resonance imaging (MRI) as it is noninvasive and as iron-labeled myoblasts provide a signal attenuation in T2*-weighted protocols. The aim of this study was to develop an efficient iron-labeling protocol for myoblasts and to visualize single-labeled cells using a clinical 1.5-T scanner. Pig myoblasts were labeled with a superparamagnetic iron oxide (SPIO) agent using a liposome transfection agent. Labeling efficiency, toxicity, cell viability, and proliferative capacity were measured for 10 days. Magnetic resonance (MR) of myoblast cultures used a T2*-weighted three-dimensional protocol with a maximum in-plane resolution of 19.5 × 26.0 m² and 50 m slices. Use of liposomes improved SPIO labeling efficiency. Labeling did not induce toxicity or affect cell viability or proliferation. The cell distribution as observed with light and fluorescence microscopy matched the signal voids observed in the MRI datasets. Liposomes promote fast, nontoxic and efficient SPIO labeling of myoblasts that can be tracked by MRI microscopy in clinical scanners using susceptibility-weighted protocols.     

Contrast-optimized composite image derived from multigradient echo cardiac magnetic resonance imaging improves reproducibility of myocardial contours and T2* measurement

Objectives

Reproducibility of myocardial contour determination in cardiac magnetic resonance imaging is important, especially when determining T2* values per myocardial segment as a prognostic factor of heart failure or thalassemia. A method creating a composite image with contrasts optimized for drawing myocardial contours is introduced and compared with the standard method on a single image.

Materials and methods

A total of 36 short-axis slices from bright-blood multigradient echo (MGE) T2* scans of 21 patients were acquired at eight echo times. Four observers drew free-hand myocardial contours on one manually selected T2* image (method 1) and on one image composed by blending three images acquired at TEs providing optimum contrast-to-noise ratio between the myocardium and its surrounding regions (method 2).

Results

Myocardial contouring by method 2 met higher interobserver reproducibility than method 1 (P < 0.001) with smaller Coefficient of variance (CoV) of T2* values in the presence of myocardial iron accumulation (9.79 vs. 15.91 %) and in both global myocardial and mid-ventricular septum regions (12.29 vs. 16.88 and 5.76 vs. 8.16 %, respectively).

Conclusion

The use of contrast-optimized composite images in MGE data analysis improves reproducibility of myocardial contour determination, leading to increased consistency in the calculated T2* values enhancing the diagnostic impact of this measure of iron overload.