Tomoyuki Kido

Three-dimensional phase-sensitive inversion recovery sequencing in the evaluation of left ventricular myocardial scars in ischemic and non-ischemic cardiomyopathy: Comparison to three-dimensional inversion recovery sequencing

BACKGROUND Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) is a useful technique for detecting myocardial fibrosis. LGE images are typically acquired using the inversion recovery (IR) method. Recently, phase-sensitive inversion recovery (PSIR) technology has been developed. The purpose of this study was to evaluate free-breathing 3D PSIR sequencing in comparison with breath-held 3D IR sequencing for the detection of myocardial fibrosis. METHODS One hundred twenty-three patients with suspected ischemic cardiac disease (n=27) or non-ischemic cardiomyopathy (hypertrophic cardiomyopathy, n=29; dilated cardiomyopathy, n=22; sarcoidosis, n=21; arrhythmia, n=9; myocarditis, n=4; amyloidosis, n=3; and others, n=8) were evaluated by LGE-MRI, which was performed first with the IR sequence and then with the PSIR sequence, using a 3T MRI scanner. Image quality was scored by two independent readers using a four-point scale. The 3D LGE volume was analyzed quantitatively and compared between both sequencing methods. RESULTS There was no significant difference in overall image quality (p=0.19). LGE was detected in 73 patients, who were evaluated visually. Ultimately, 58 patients with acceptable image quality were enrolled in further quantitative analyses (volume assessment). Although quantification of LGE volume revealed a strong correlation between both methods, larger LGE volumes were detected with PSIR compared to IR in patients suspected of non-ischemic cardiomyopathy (39.5 ± 25.9 cm(3) for PSIR and 32.8 ± 23.9 cm(3) for IR, p<0.001). The LGE volume did not differ significantly in patients suspected of ischemic cardiac disease (17.9 ± 12.7 cm(3) for PSIR and 17.5 ± 11.1cm(3) for IR, p=0.34). CONCLUSIONS 3D PSIR is suitable for detection of LGE and may be an option in cases with IR images of unacceptable quality but overestimates LGE volume in non-ischemic cardiomyopathy.

Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

PURPOSE We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. METHODS In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n=485), ischemic (n=74), or infarcted (n=49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. RESULTS A cutoff value of -12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3ms for time-to-peak CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 61%, specificity of 91%, accuracy of 88%, and an AUC of 0.75. The differences in CS values between ATP-stress and rest conditions (ΔCS) in non-ischemic segments (median [first quartile, third quartile] -1.7 [-3.2, -0.1] %) were smaller than in segments with ischemia (+1.1 [+0.3, +2.3] %, p<0.001). A cutoff value of +0.3% for the ΔCS value could differentiate segments with ischemia from non-ischemic segments with a sensitivity of 75%, a specificity of 82%, an accuracy of 82%, and an AUC of 0.86. CONCLUSIONS Circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium.

Assessment of Left Ventricular Function and Mass on Free-Breathing Compressed Sensing Real-Time Cine Imaging

BACKGROUND Compressed sensing (CS) cine magnetic resonance imaging (MRI) has the advantage of being inherently insensitive to respiratory motion. This study compared the accuracy of free-breathing (FB) CS and breath-hold (BH) standard cine MRI for left ventricular (LV) volume assessment.Methods and Results:Sixty-three patients underwent cine MRI with both techniques. Both types of images were acquired in stacks of 8 short-axis slices (temporal/spatial resolution, 41 ms/1.7×1.7×6 mm3) and compared for ejection fraction, end-diastolic and systolic volumes, stroke volume, and LV mass. Both BH standard and FB CS cine MRI provided acceptable image quality for LV volumetric analysis (score ≥3) in all patients (4.7±0.5 and 3.7±0.5, respectively; P<0.0001) and had good agreement on LV functional assessment. LV mass, however, was slightly underestimated on FB CS cine MRI (median, IQR: BH standard, 83.8 mL, 64.7-102.7 mL; FB CS, 79.0 mL, 66.0-101.0 mL; P=0.0006). The total acquisition times for BH standard and FB CS cine MRI were 113±7 s and 24±4 s, respectively (P<0.0001). CONCLUSIONS Despite underestimation of LV mass, FB CS cine MRI is a clinically useful alternative to BH standard cine MRI in patients with impaired BH capacity.

Single breath-hold real-time MR cardiac cine for evaluation of left ventricular function

Background Magnetic Resonance (MR) cardiac cine is generally accepted as the gold standard for left ventricular (LV) volume assessment. Recently, Real-Time (RT) cine with sparse sampling technique and iterative reconstruction has been applied to accelerate cine MR. However, in prospective electrocardiogram (ECG) triggered RT cine MR, it may be difficult to capture the true end diastole phase because of the finite time needed to detect the next ECG trigger, which may lead to underestimation of end diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) when compared with retrospective ECG gated standard cine MR. In this study we propose an alternative approach to overcome this limitation, by acquiring sparse RT cine MR data over two heart beats, to capture the complete end diastole between the first and second heart beats. The purpose of this study was to evaluate the diagnostic quality and accuracy of RT-based single-breath-hold cine MR for the quantification of LV function compared with standard multi-breath-hold cine MR.

Cardiac magnetic resonance imaging for assessment of steroid therapy in a patient with cardiac sarcoidosis and a magnetic resonance-conditional pacemaker

Cardiacmagnetic resonance imaging for assessment of steroid therapy in a patient with cardiac sarcoidosis and a magnetic resonance-conditional pacemaker Tamami Kono ⁎, Akiyoshi Ogimoto , Makoto Saito , Kaori Fujimoto , Akira Fujii , Teruyoshi Uetani , Takayuki Nagai , Kazuhisa Nishimura , Katsuji Inoue , Jun Suzuki , Takafumi Okura , Tomoyuki Kido , Masao Miyagawa , Teruhito Mochizuki , Jitsuo Higaki a

Supravalvular thrombus after pulmonary artery banding and fontan procedure evaluated by multidetector-row computed tomography

The mechanisms responsible for thromboembolic events in children with congenital heart disease have not yet been fully elucidated. Furthermore, establishment of long-term anticoagulation therapy in Fontan patients remains controversial. Here, we report the case of a 9-year-old boy who presented with hemiparesis due to a thromboembolic stroke; the boy had previously undergone staged pulmonary artery banding and Fontan procedure. Cardiac multidetector-row computed tomography (MDCT) clearly showed the supravalvular thrombus at the roofed (blind) pulmonary valve and circulatory stasis, which could be considered a possible source of the thrombus. Follow-up CT examination showed that the thrombus disappeared, but the circulatory stasis remained. Therefore, because the risk of thrombus formation was not eliminated, anticoagulation therapy was continued for the patient. Our case indicates the possible application of cardiac MDCT for providing insight into the hemodynamic mechanisms responsible for the thromboembolic events in children with congenital heart disease.

Diagnostic capability of feature-tracking cardiovascular magnetic resonance to detect infarcted segments: a comparison with tagged magnetic resonance and wall thickening analysis

AIM To examine the diagnostic capabilities of feature-tracking cardiovascular magnetic resonance (FT-CMR), tagged cine magnetic resonance (MR), and wall thickening (WT) analyses to detect infarcted segments in patients with established myocardial infarction (MI). MATERIALS AND METHODS Twenty patients with established MI were selected retrospectively and the peak endocardial circumferential strain (CS) was quantified based on the 16-segment model. According to CMR with late gadolinium enhancement, segments were categorised as transmural MI, subendocardial MI, and no MI. RESULTS A total of 320 segments (62 transmural MI, 50 subendocardial MI, and 208 no MI) were analysed. Peak endocardial CS was significantly lower for transmural MI compared with subendocardial MI (p<0.05) and no MI (p<0.001). Cut-off values of -11.2% for CS by FTCMR, -10.9% for CS by tagged MR, and 23.8% for %WT, differentiated between infarcted and non-infarcted segments with a sensitivity of 72%, 71%, and 56%; specificity of 71%, 75%, and 67%; accuracy of 72%, 73%, and 63%; positive predictive value of 57%, 60%, and 48%; negative predictive value of 83%, 83%, and 74%; and an area-under-the-curve of 0.77, 0.79, and 0.64, respectively. CONCLUSIONS FT-CMR was diagnostically superior to %WT, and could differentiate between subendocardial and transmural MI. Unlike tagged MR, FT-CMR did not require the acquisition of additional sequences.

Magnetic resonance assessment of fetal lung maturity: comparison between signal intensity and volume measurement

PurposeWe evaluated the associations between gestational age (GA) and lung-to-liver signal intensity ratio (LLSIR) and fetal lung volume (FLV) using magnetic resonance imaging (MRI). Moreover, we evaluated the reproducibility of these measurements.Materials and methodsLLSIR and FLV were measured using single-shot fast spin-echo MRI in 88 consecutive fetuses. The Spearman test was used to assess the relationships between (1) LLSIR and GA, and (2) FLV and GA in 81 fetuses without lung abnormalities. Intra- and inter-observer reliabilities were assessed using intra-class correlation coefficients (ICCs).ResultsOverall, GA and LLSIR were significantly correlated (r = 0.62, p < 0.001). However, GA and LLSIR were only significantly correlated during the third trimester (before third trimester: r = 0.39, p = 0.08; during third trimester: r = 0.46, p < 0.001). Overall, GA and FLV were significantly correlated (r = 0.72, p < 0.001). FLV was significantly correlated with GA before (r = 0.86, p < 0.001) and during the third trimester (r = 0.47, p < 0.001). All ICCs were above 0.90.ConclusionsLLSIR and FLV are useful for the assessment of fetal lung maturity and are highly reproducible. Before the third trimester, FLV is more suitable than LLSIR for the evaluation of fetal lung maturity.

Non-contrast compressed sensing whole-heart coronary magnetic resonance angiography at 3T: A comparison with conventional imaging

OBJECTIVES Whole-heart coronary magnetic resonance angiography (MRA) is a promising non-contrast, radiation-free technique for assessing the coronary artery. Yet, a disadvantage of coronary MRA is the relatively long acquisition time. The purpose of this study was to evaluate the scan time and image quality of compressed sensing (CS) coronary MRA compared with conventional coronary MRA. MATERIALS AND METHODS Twenty healthy volunteers underwent navigator-gated coronary MRA with a CS prototype sequence and conventional navigator-gated coronary MRA on a clinical 3T MRI scanner without contrast medium. The spatial resolutions were 1.33 × 1.33 × 1.20 mm3 for CS and 1.33 × 1.33 × 1.48 mm3 interpolated to 0.70 × 0.70 × 1.20 mm3 for conventional, respectively. We compared acquisition times, rated image quality on a 4-point scale (RCA; proximal, middle, and distal, LAD; main, proximal, middle, and distal, LCX; proximal and distal), and measured the visualized vessel lengths of three vessels. RESULTS The mean acceptance rates were 44.9% for CS coronary MRA and 48.7% for conventional coronary MRA (p = .39). The mean effective scan time was 3 min 45 s for CS coronary MRA and 15 min 6 s for conventional coronary MRA (p < 0.001). Image quality scores were significantly lower for CS coronary MRA than for conventional coronary MRA (3.4 ± 0.7 for CS vs. 3.8 ± 0.4 for conventional; p < 0.0001). Conventional coronary MRA images were scored >3.4 in all segments on average, while CS coronary MRA images were scored >3.2 (good quality for diagnosis) in almost all segments, with only the distal RCA segment graded 2.9 on average. The average visible vessel lengths for CS and conventional coronary MRA were as follows: 11.5 ± 4.4 cm and 12.5 ± 4.8 cm for the RCA, respectively (p < 0.05, 95% limits of agreement [LOA]; -3.6 to 1.6 cm); 10.6 ± 3.0 cm and 11.1 ± 2.9 cm for the LAD, respectively (p = .15, 95% LOA -4.0 to 2.8 cm); and 7.1 ± 2.2 cm and 8.2 ± 2.5 cm for the LCX, respectively (p < 0.05, 95% LOA -4.0 to 1.7 cm). CONCLUSIONS Non-contrast coronary MRA using CS could largely shorten acquisition time, compared with conventional navigator-gated coronary MRA, while maintaining acceptable visualization at 3T.

Quantitative circumferential strain analysis using 3-Tesla feature-tracking cardiovascular magnetic resonance in patients with old myocardial infarction

Background Feature-tracking cardiovascular magnetic resonance (FTCMR) provides quantification of myocardial strain by analyzing cine MR images. A previous study has reported that CS measured by FT-CMR showed reasonable agreement with tagged MR in healthy volunteers. However, the usefulness of FT-CMR in patients with old myocardial infarction (OMI) has not been investigated. The purpose of this study was to evaluate diagnostic ability of CS by FT-CMR in patients with OMI.