Optimization of 201Tl Dosage in a Simultaneous Acquisition Rest 99mTc/Stress 201Tl Dual-Isotope Myocardial Perfusion Single-Photon Emission Computed Tomography with Semiconductor Gamma Camera.

Background: The use of 201Tl in myocardial perfusion single-photon emission computed tomography (SPECT) is predominantly not recommended because of the higher radiation exposure of 201Tl compared to 99mTc agent. However, the advent of new gamma cameras with semiconductor detectors has made it possible to reduce the 201Tl dose and lower radiation exposure. In our hospital, the dose of 201Tl is adjusted according to the patient's body mass index (BMI), with 50 MBq for BMI<25 and 74 MBq for BMI≥25. The dose of 201Tl during simultaneous acquisition dual-isotope myocardial perfusion SPECT (MPS; stress 201Tl and rest 99mTc agent) exceeds 9 mSv/examination when 74 MBq of 201Tl is administered. In order to further reduce the radiation dose, optimization of the 201Tl dose was investigated. Methods: Two hundred and eighty consecutive patients who underwent stress MPS using simultaneous acquisition dual-isotope protocol (SDI protocol) for the estimation of ischemic heart disease were included. Patients with prior myocardial infarction were excluded. Correlations between BMI and acquisition time were determined in patients receiving 50 MBq (n=154) or 74 MBq (n=126) of 201Tl. In addition, linear regression analysis was used to determine the slope and intercept to derive a linear functional equation, and the theoretically optimal 201Tl dose was evaluated. Results: The correlation coefficient between BMI and acquisition time in the 201Tl 50 MBq group was 0.532 (P< 0.00001) and in the 201Tl 74 MBq group was 0.478 (P<0.00001), both showing a positive correlation. Linear regression analysis yielded two equations: y=0.52x-0.32 (201Tl 50 MBq group) and y=0.41x-0.69 (201Tl 74 MBq group). Linear function equation results indicated that patients with BMI between 25 and 30 could be examined within approximately 15 minutes with 50 MBq of 201Tl. Conclusion: Considering examination efficiency, a single acquisition time of less than 15 minutes is ideal. Theoretically, patients with BMI less than 30 could be examined within approximately 15 minutes with 50 MBq of 201Tl.

Optimal Protocol of Myocardial Perfusion Imaging for Reduction of Radiation Exposure.

The Japanese Circulation Society (JCS) 2021 guideline on radiation safety in cardiology was updated based on the eight best practices for myocardial perfusion single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), which was determined by panels of international atomic energy agency (IAEA) nuclear cardiology protocols cross-sectional study (INCAPS). Although the guideline recommends to avoid too much 201Tl or 201Tl/99mTc dual-isotope protocol, the utilization rate of 201Tl for SPECT-MPI in Japan is considerably high compared to other countries. In Japan, protocols using 99mTc should be appropriately promoted based on the guideline to reduce radiation exposure in SPECT-MPI. Among the eight practices, stress-only imaging is considered to be a useful strategy that contributes to a significant reduction in radiation exposure, and hybrid assessment in combination with rest computed tomography (CT)-MPI is one of the practical application methods.

Relationship Among Coronary Artery Calcium Score, Myocardial Perfusion SPECT and Risk Stratification of Coronary Artery Disease.

Since Agatston et al. first reported quantification of the coronary artery calcification score (CACS) in 1990, discussion of its clinical significance and use in diagnostic management has continued. Recent papers have reported the relationship between CACS and myocardial perfusion single photon emission computed tomography (SPECT: MPS) and its combined diagnostic value. When interpreting CACS results, it should be noted that the frequency of significant ischemia detected by MPS, likelihood of coronary artery disease (CAD), and event rate gradually increased from mild to moderate CACS (1-400). At present, high CACS is considered to be moderately consistent with abnormal MPS, and abnormal CACS in normal MPS may contribute to CAD risk stratification. However, it should be noted that CACS=0 does not completely exclude CAD, which is particularly important when using CACS as a gatekeeper for MPS. Both stand-alone computed tomography (CT) scanner and hybrid SPECT-CT scanner are available for combined risk stratification of CACS and MPS in addition to improvement of image quality with attenuation correction.

Measurement of Turbulent Kinetic Energy in Hypertrophic Cardiomyopathy Using Triple-velocity Encoding 4D Flow MR Imaging.

PURPOSE: The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). METHODS: From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. RESULTS: TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). CONCLUSION: TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.

Clinical Utility of a Slow 201Tl Washout Rate in the Detection of Multi-Vessel Coronary Artery Disease Using a Simultaneous Acquisition Rest 99 mTc/Stress 201Tl Protocol and a Semiconducting Gamma Camera.

BACKGROUND: The diagnostic accuracy of stress myocardial perfusion single-photon emission computed tomography (SPECT) to detect coronary artery disease (CAD) is reduced by the balanced reduction of myocardial perfusion in patients with multi-vessel or left main trunk CAD (multi-vessel group). This study investigated the diagnostic performance of a simultaneous acquisition rest 99 mTc/stress 201Tl dual-isotope protocol for myocardial perfusion SPECT (MPS) in a multi-vessel group by examining the assessment of a slow 201Tl washout rate (WR) finding in comparison to the accuracy of perfusion assessments.Methods and Results: This study enrolled 91 patients who had undergone angiography within 3 months after MPS. The diagnostic performances of perfusion assessments and a slow 201Tl WR parameter were compared using the area under the curve (AUC) in a multi-vessel group of patients with mild ischemia (2≤summed difference score [SDS]≤7). The AUC of a slow WR parameter was significantly larger compared with that for perfusion assessments, in patients with mild ischemia, (AUC, 0.736 vs. 0.504-0.558, P value: <0.01-0.05). CONCLUSIONS: Among patients with mild ischemia, a slow 201Tl WR parameter improved the detection of CAD in a multi-vessel group.

Localization of Late Gadolinium Enhancement and Its Association with Ventricular Tachycardia in Patients with Cardiac Sarcoidosis.

Sustained ventricular tachycardia (sVT), leading to sudden cardiac death, is one of the common manifestations in cardiac sarcoidosis (CS). Although late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) has been reported to be associated with sVT, the relationships of its localization to sVT have not been fully evaluated.To evaluate the localization of LGE and its relationships to sVT in patients with CS, we reviewed medical record of consecutive 31 patients with CS who underwent CMR. The localization of LGE was divided into four categories: Left ventricular (LV) septum, LV free wall, right ventricular (RV) septum, and RV free wall. We investigated the association of sVT with localization of LGE and other parameters including serum biomarkers LV ejection fraction on echocardiography and Fluorine-18-fluorodeoxyglucose (FDG) accumulation on positron emission tomography (PET) -CT.Of the studied population, 8 patients (25.8%) were known to present with sVT among 31 CS patients. LGE was observed in the RV free wall in 6 patients with sVT, whereas it was in 5 patients without sVT (75.0% versus 21.7%, P = 0.022). Univariate analysis showed that only LGE in the RV free wall was associated with sVT (odds ratio [OR]: 10.80; 95% confidence interval [CI]: 1.64-70.93, P = 0.013).LGE in the RV free wall was associated with sVT in patients with CS.

Coronary artery calcium score: Current status of clinical application and how to handle the results.

The clinical significance of the coronary artery calcium score (CACS) has been discussed since Agatston et al. first reported its utility in 1990. CACS is less invasive and less expensive than contrast-enhanced coronary computed tomography (CT) angiography. However, to date, discussion continues on who is eligible for CACS assessment and how test results should be handled. Although the CACS cutoff value of 400 has been used in many previous studies for the detection of significant coronary artery disease (CAD) or cardiac event risk, other studies have reported that the frequency of significant ischemia, likelihood of CAD, and cardiac event rate are increasing, from mild to moderate CACS. The prognostic significance of patients with moderate CACS (1-400) is still uncertain, whereas in 2016, the Society of Cardiovascular CT and Society of Thoracic Radiology guidelines determined CACS ≥300 as moderate to severely increased risk. Another important value is CACS = 0. It is known that CACS = 0 decreases the likelihood of CAD after assessment of the pretest probability. In addition, management using statin therapy is a clinical situation that may benefit from CACS = 0. A previous study reported no significant difference in the prognosis between patients with and without statin therapy with CACS = 0. Some studies have reported the significance of the combination of CACS and noninvasive cardiac imaging, whereas CACS assessment is recommended for use in combination with risk assessment of pretest probability using clinical information including age, sex, and chest symptoms. While the utility of CACS in the management of CAD and primary prevention has been reconfirmed, the benefit of moderate values of CACS to predict prognosis with subsequent treatment and noninvasive cardiac imaging is still controversial.

Cross-Comparison of 4-Dimensional Flow Magnetic Resonance Imaging and Intraoperative Middle Cerebral Artery Pressure Measurements Before and After Superficial Temporal Artery-Middle Cerebral Artery Bypass Surgery.

BACKGROUND: The hemodynamic changes after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery are unclear. OBJECTIVE: To clarify the hemodynamics by comparing flow parameters obtained by 4-dimensional (4D) flow magnetic resonance imaging (MRI) and intraoperative MCA pressure measurement. METHODS: We recruited 23 patients who underwent STA-MCA bypass surgery for internal carotid artery (ICA) or MCA stenosis. We monitored intraoperative MCA, STA, and radial artery (RA) pressure. All patients underwent 4D flow MRI preoperatively and 3 wk after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), contralateral ICA (BFVcICA), basilar artery (BFVBA), ipsilateral STA (BFViSTA), and contralateral STA (BFVcSTA). The sum of intracranial BFV was defined as BFVtotal. We compared BFV parameters and intraoperative pressure. RESULTS: BFViSTA significantly increased after surgery (P < .001). BFViICA and BFVBA significantly decreased after surgery (BFViICAP = .005; BFVBAP = .02). No significant difference was observed between BFVcICA before and after surgery. As a result, BFVtotal postoperatively increased by 6.8%; however, no significant difference was observed. Flow direction at M1 changed from antegrade to unclear after surgery in 5 patients. Intraoperative MCA pressure and MCA/RA pressure ratio significantly increased after surgery (P < .001). We found a stronger positive correlation between MCA pressure increase ratio and BFVtotal increase ratio in patients with lower pre-MCA pressure (r = 0.907, P < .001). CONCLUSION: The visual and quantitative assessment of 4D flow MRI revealed that intracranial blood flow changes complementarily after STA-MCA bypass surgery. 4D flow MRI may detect the improvement of cerebral perfusion pressure.

Case report of portal hepatic schwannoma: presentation of multimodality images.

BACKGROUND: Portal hepatic schwannoma is a rare benign tumor and difficult to diagnose preoperatively because of its rarity and imaging manifestations that mimic malignancy. We present a case of portal hepatic schwannoma that showed moderate contrast enhancement on computed tomography (CT), extension along the bile duct on T2-weighted imaging and magnetic resonance cholangiopancreatography (MRCP), and uptake of 18F-fluorodeoxyglucose (FDG) on positron emission tomography. CASE PRESENTATION: Ultrasonography at an annual health checkup identified a hepatic mass in a 38-year-old woman. CT showed a well-defined portal hepatic tumor with mild contrast enhancement. T2-weighted imaging and MRCP showed a clavate tumor extending along the intrahepatic bile ducts but no dilatation of the ducts. The tumor exhibited increased FDG uptake, such as maximum standardized uptake values of 5.0 and 6.5 in the early and late phases, respectively. Neither dilatation of intrahepatic bile ducts nor lymphadenopathy was identified, and the multimodality imaging suggested hepatic portal lymphoma, gastrointestinal tumor, or IgG4-related disease rather than cholangiocarcinoma. A needle biopsy via endoscopic ultrasonography was performed, and immunohistology confirmed the tumor as a schwannoma. CONCLUSIONS: The diagnosis of a portal hepatic schwannoma requires immunohistological examinations in addition to multimodality imaging studies to reflect fully the pathohistological characteristics of the tumor.

[Effects of Heart Rate on Myocardial Native T1 Value Acquired by 5s(3s)3s MOLLI Sequence].

Quantitative evaluation of myocardial native T1 value by measuring modified Look-Locker inversion recovery (MOLLI) method is clinically useful and is used for follow-up of various myocardial diseases. The heart rate during the scan can vary even in the same subjects. Therefore, it is important to know the effects of the heart rate on the native T1 value of the myocardium. In this study, we evaluated the effect of the heart rate on the T1 value in the 5s (3s) 3s scheme, time control data collection period of the MOLLI method, using phantom experiments and experiments of healthy volunteers. The 5s (3s) 3s scheme of the MOLLI method is considered to have little dependence on the heart rate, but the T1 value still varied up to about 7% depending on the heart rate, and was underestimated up to 8% during low heart rate using phantom experiments.

Incremental Predictive Value of Coronary Calcium Score in Risk Stratification of Coronary Revascularization in Patients With Normal or Mild Ischemia Using Nuclear Myocardial Perfusion Single Photon Emission Computed Tomography.

BACKGROUND: The incremental predictive value of the coronary artery calcium score (CACS) for risk stratification of coronary revascularization in patients with normal or mildly abnormal nuclear myocardial perfusion single photon emission computed tomography (MPS) scores is unknown.Methods and Results:We analyzed 528 patients in whom CACS was calculated and who underwent stress MPS within 3 months. Patients with known coronary artery disease, prior coronary revascularization, and those undergoing hemodialysis were excluded. Patients were followed-up with coronary revascularization based on the evidence of physiological ischemia defined by fractional flow reserve or severe coronary stenosis (≥90%). CACS was significantly associated with the summed stress score (SSS) from MPS assessment. Multivariate logistic regression analysis showed that high CACS (≥300; odds ratio [OR] 5.44, 95% confidence interval [CI] 2.28-13.0) and SSS (OR 1.29, 95% CI 1.18-1.40) were significant (P<0.001) predictors of future coronary revascularization. The log-rank test showed that high CACS stratified coronary revascularization in normal SSS (0-3; P<0.001) or mildly abnormal SSS (4-8; P=0.028) groups, whereas high CACS did not significantly stratify coronary revascularization in moderate to severe SSS (≥9; P=0.757). CONCLUSIONS: Risk stratification using CACS with a cut-off value 300 may have incremental predictive value for revascularization in patients with normal or mildly abnormal MPS.

Clinical Importance of Myocardial T2 Mapping and Texture Analysis.

Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) is valuable for diagnosis and assessment of the severity of various myocardial diseases owing to its potential to visualize myocardial scars. T1 mapping is complementary to LGE because it can quantify the degree of myocardial fibrosis or edema. As such, T1-weighted imaging techniques, including LGE using an inversion recovery sequence, contribute to cardiac MRI. T2-weighted imaging is widely used to characterize the tissue of many organs. T2-weighted imaging is used in cardiac MRI to identify myocardial edema related to chest pain, acute myocardial diseases, or severe myocardial injuries. However, it is difficult to determine the presence and extent of myocardial edema because of the low contrast between normal and diseased myocardium and image artifacts of T2-weighted images and the lack of an established method to quantify the images. T2 mapping quantifies myocardial T2 values and help identify myocardial edema. The T2 values are significantly related to the clinical symptoms or severity of nonischemic cardiomyopathy. Texture analysis is a postprocessing method to quantify tissue alterations that are reflected in the T2-weighted images. Texture analysis provides a variety of parameters, such as skewness, entropy, and grey-scale non-uniformity, without the need for additional sequences. The abnormal signal intensity on T2-weighted images or T2 values may correspond to not only myocardial edema but also other tissue alterations. In this review, the techniques of cardiac T2 mapping and texture analysis and their clinical relevance are described.

Epithelioid Hemangioma of Vertebra Mimicking Metastasis on FDG PET/CT in a Patient With Renal Cell Cancer.

ABSTRACT: Vertebral epithelioid hemangioma is a rare vascular tumor composed of the many vessels lined by distinct epithelioid endothelial cells. We present the case of a patient with renal cell cancer (RCC) and suspicious vertebral metastasis presenting with back pain, who was later found to have epithelioid hemangioma. FDG PET/CT demonstrated uptake of FDG not only in RCC, but also in the sixth thoracic vertebral body. The SUVmax of the vertebra was more than twice as high as RCC. This report indicates importance of quantitative assessment of FDG uptake, as well as combined use of MRI.

Hybrid Assessment of Myocardial Ischemia Using Stress-Only Nuclear Myocardial Perfusion Imaging and Rest Computed Tomography Perfusion Imaging.

BACKGROUND: Sequential assessment using CT coronary angiography (coronary CT) and nuclear myocardial perfusion imaging (MPI) is considered an anatomical and functional evaluation of coronary artery disease (CAD). However, there can be unexpected radiation exposure. Hybrid MPI with stress-only nuclear MPI and rest CT-MPI using coronary CT may contribute to reducing the radiation dose in sequential assessment with nuclear MPI after coronary CT. We analyzed the diagnostic performance and total radiation dose of hybrid MPI for detection of significant CAD compared with sequential assessment using nuclear MPI after coronary CT.Methods and Results:The results for 101 patients who underwent coronary CT, nuclear MPI and invasive coronary angiography within 3 months of all imaging were analyzed. We calculated the summed difference score (SDS) from standard nuclear MPI and hybrid SDS from hybrid MPI, which revealed myocardial ischemia. The diagnostic performance of SDS and hybrid SDS for detecting significant CAD was analyzed using receiver-operating characteristic (ROC) curve analysis. We also compared the total radiation dose of both methods. The area under the ROC curve was not different between SDS and hybrid SDS (0.901 and 0.815, P=0.079). Total radiation dose of hybrid MPI was significantly lower than standard nuclear MPI with CT angiography (4.62 mSv vs. 9.72 mSv, P<0.0001). CONCLUSIONS: Hybrid MPI showed a precise diagnostic accuracy for significant CAD detection.

Multiparametric flow analysis using four-dimensional flow magnetic resonance imaging can detect cerebral hemodynamic impairment in patients with internal carotid artery stenosis.

PURPOSE: MRI-based risk stratification should be established to identify patients with internal carotid artery stenosis (ICS) who require further PET or SPECT evaluation. This study assessed whether multiparametric flow analysis using time-resolved 3D phase-contrast (4D flow) MRI can detect cerebral hemodynamic impairment in patients with ICS. METHODS: This retrospective study analyzed 26 consecutive patients with unilateral ICS (21 men; mean age, 71 years) who underwent 4D flow MRI and acetazolamide-stress brain perfusion SPECT. Collateral flow via the Willis ring was visually evaluated. Temporal mean flow volume rate (Net), pulsatile flow volume (ΔV), and pulsatility index (PI) at the middle cerebral artery were measured. Cerebral vascular reserve (CVR) was calculated from the SPECT dataset. Patients were assigned to the misery perfusion group if the CVR was < 10% and to the nonmisery perfusion group if the CVR was ≥ 10%. Parameters showing a significant difference in both groups were statistically evaluated. RESULTS: Affected side ΔV, ratio of affected to contralateral side Net (rNet), and ratio of affected to contralateral side ΔV were significantly correlated to CVR (p = 0.030, p = 0.010, p = 0.015, respectively). Absence of retrograde flow at the posterior communicating artery was observed in the misery perfusion group (p = 0.020). Combined cut-off values of the affected side ΔV (0.18 ml) and rNet (0.64) showed a sensitivity and specificity of 100% and 77.8%, respectively. CONCLUSION: Multiparametric flow analysis using 4D flow MRI can detect misery perfusion by comprehensively assessing blood flow data, including blood flow volume, pulsation, and collateral flow.

Detection of Myocardial Tissue Alterations in Hypertrophic Cardiomyopathy Using Texture Analysis of T2-Weighted Short Inversion Time Inversion Recovery Magnetic Resonance Imaging.

OBJECTIVE: The aim of this study was to evaluate the usefulness of texture analysis of T2-weighted short inversion time inversion recovery (T2-STIR) for detecting myocardial tissue alterations in hypertrophic cardiomyopathy (HCM). METHODS: Twenty patients with HCM and 11 controls were examined. Texture analysis was performed for the hypertrophied regions with and without and abnormal hyperintensity (AHI) and for the interventricular septum of the controls on T2-STIR. T2 mapping was performed to measure myocardial T2 values. RESULTS: A gray-level nonuniformity value of 64.7 was the best discriminator between patients and controls with an area under the curve of 0.93 on a receiver operating characteristic curve. T2 values did not differ between them. The gray-level nonuniformity was significantly smaller in AHI regions than in the hypertrophied regions without AHI in HCM patients. CONCLUSIONS: Texture analysis is useful for quantitatively detecting myocardial tissue altenations, including AHI, associated with HCM on T2-STIR.

Long-term prognostic value of ultrastructural features in dilated cardiomyopathy: comparison with cardiac magnetic resonance.

AIMS: This study aims to determine the implications associated with long-term prognosis of heart failure (HF) in patients with dilated cardiomyopathy (DCM) presenting initially as decompensated HF. We stratified the phase of DCM patients without late gadolinium enhancement (LGE) based on ultrastructural changes in cardiomyocytes. METHODS AND RESULTS: Left ventricular (LV) endomyocardial biopsy was performed in 55 consecutive DCM patients with initial decompensated HF. Ultrastructural changes in cardiomyocytes detected by electron microscopy were compared with data including LGE with cardiac magnetic resonance and HF recurrence. Of the 55 DCM patients, 24 (44%) showed LGE, and 26 (47%) showed recurrence decompensated HF, while 23 patients (42%) showed autophagic vacuoles in cardiomyocytes by electron microscopy. Multivariate analysis identified atrial fibrillation [hazard ratio (HR), 3.40; 95% confidence interval (CI), 1.45-7.98], haemoglobin level (HR, 0.82; 95% CI, 0.68-0.99), beta-blocker use (HR, 0.18; 95% CI, 0.05-0.74), and autophagic vacuoles (HR, 0.25; 95% CI, 0.09-0.65) as predictors of HF recurrence in the total patient population. In patients without LGE, only autophagic vacuoles were independent predictors of readmission because of HF (HR, 0.29; 95% CI, 0.09-0.90). In patients with LGE, atrial fibrillation (HR, 19.10; 95% CI, 2.97-123.09), and mid-linear LGE (HR, 12.96; 95% CI, 2.02-82.94) were independent predictors of readmission because of HF. CONCLUSIONS: In DCM patients with LGE, characterised by progression of LV remodelling, the LGE pattern was a predictor of HF recurrence, whereas in patients without LGE, absence of autophagic vacuoles was a predictor of HF recurrence.

Relationship between Measurement Errors in Myocardial T1 Mapping and Heart Rate.

PURPOSE: Modified Look-Locker inversion recovery (MOLLI) using a 5s(3s)3s scheme is robust to tachycardia, but some errors are occasionally observed in myocardial T1 mapping. We sought to evaluate the relationship between measurement errors in T1 mapping and heart rate (HR) using a confidence map. METHODS: We enrolled 69 male patients with normal native T1 values of the septal myocardium measured by a 5s(3s)3s MOLLI. The degree of measurement errors in the septal myocardium was assessed by two independent observers on a confidence map using a 4-point scale: 0, no errors; 1, errors located on the myocardial contour; 2, errors extended into the myocardial contour; and 3, errors extended into the midwall. We compared the scores of measurement errors and the average, maximum, minimum or variability of the HR indicated during the MOLLI scan (iHR), image phases of MOLLI or left ventricular ejection fraction (LVEF). RESULTS: Patients with score >1 for the septal myocardium had significantly lower minimum iHR than those with a score ≤1 (P < 0.01; 49.8 ± 10.1 vs. 59.6 ± 9.7 beat per min). CONCLUSION: The confidence map shows more measurement errors in patients with lower minimum iHR. The myocardial T1 values should be measured carefully in patients with bradycardia during MOLLI scanning.