Diagnostic value of Flash dual-source CT coronary artery imaging combined with dual-energy myocardial perfusion imaging for coronary heart disease

Quadruple-Rule-Out Computed Tomography Angiography (QRO-CT): A Novel Dual-Energy Computed Tomography Technique for the Diagnostic Work-Up of Acute Chest Pain

BACKGROUND

Computerized tomography (CT) has been increasingly utilized in the differential diagnosis of acute chest pain. Combining the triple rule out CT angiography (TRO-CT) approach with dual-energy CT (DECT) can enhance the diagnostic capability by identifying myocardial perfusion deficiencies. This combination can yield a quadruple-rule-out computed tomography angiography (QRO-CT) technique. The aim of this study is to determine the efficacy of the QRO-CT.

METHODS

Intraluminal diseases and abnormalities in the main coronary arteries and branches were investigated. The myocardial dark spots on the color-coded iodine map were identified as perfusion deficiencies. Pulmonary arteries and aorta were also evaluated.

RESULTS

The study population consisted of 211 patients. The sensitivity, specificity, and positive and negative predictive values of QRO-CT for pulmonary embolism were 93.5%, 100%, 100%, and 95.3%, respectively. For obstructive coronary artery disease, the values were 96.1%, 93.4%, 89.2%, and 97.7%, respectively. For myocarditis, the values were 69.2%, 100%, 100%, and 93.6%, respectively.

CONCLUSIONS

the QRO-CT method may successfully evaluate myocardial perfusion deficits, hence expanding the differential diagnosis capabilities of the standard TRO-CT method for myocarditis. It can provide useful information on myocardial perfusion, which may influence the choice to perform invasive catheterization in cases of coronary artery obstruction.

The value of dual-energy computed tomography in the evaluation of myocarditis

PURPOSE

The inflammation of the heart muscle is referred to as acute myocarditis. Cardiac magnetic resonance imaging (CMR) has become the primary method for a non-invasive assessment of myocardial inflammation. However, there are several drawbacks of CMR. During the last decade, dual energy computed tomography (DECT) has been used in cardiac imaging. The current study aims to assess the efficacy and feasibility of DECT in acute myocarditis and compare the results to CMR.

METHODS

This prospective study included patients who had myocarditis but no coronary artery pathology. Two observers evaluated the patients for acute myocarditis using DECT and CMR. CMR was performed on 22 patients within 24 hours of DECT, which was administered within 12 hours following the onset of chest pain. Inter-observer agreement was tested with Cohen's Kappa coefficient, and Spearman's correlation was used to examine the possible correlations. A P value of <0.050 was accepted as statistically significant.

RESULTS

The DECT and CMR agreement was significant for transmural diagnoses, excellent for subepicardial and intramyocardial diagnoses, and perfect for nodular and band-like patterns.

CONCLUSION

The findings of this study showed that the dark areas on the color-coded iodine map created with DECT were strongly correlated with CMR in acute cases of myocarditis. In addition, DECT is a robust imaging method that can also be used in the diagnosis of acute myocarditis. Furthermore, it provides information about coronary arteries faster and more reliably than magnetic resonance imaging without any limitations.

Low-dose ultra-high-pitch computed tomography coronary angiography: identifying the optimum combination of iteration strength and radiation dose reduction strategies to achieve true submillisievert scans

PURPOSE

To identify the optimum strength of advanced modeled iterative reconstruction (ADMIRE) to achieve the best subjective and objective image quality when combining three-dose reduction strategies, ultra-high-pitch computed tomography coronary angiography (FLASH CTCA; with single-dose ivabradine to lower heart rate), low tube voltage, and ADMIRE.

METHODS

Sixty consecutive patients underwent FLASH CTCA at 100 kVp in this single-center prospective study. Single-dose ivabradine was administered to patients whose heart rate was above 75 bpm. Images were reconstructed using the three highest strengths of ADMIRE (A3, A4, and A5). Objective and subjective image quality (using a Likert scale) were evaluated in the three datasets.

RESULTS

The signal strength remained unchanged but mean noise significantly reduced across the increasing strengths of ADMIRE [signal: 513.78 ± 101.7 Hounsfield units (HU) at A3, 515.6 ± 100.5 HU at A4, and 519.7 ± 107.9 HU at A5; noise: 23.4 ± 4.5 HU at A3, 20.2 ± 3.6 HU at A4, and 17.2 ± 3.3 HU at A5]. Signal-to-noise and contrast-to-noise ratios were the highest at A5, and A5 offered significantly higher Likert scores in image noise, vessel sharpness, and overall image quality than A3 or A4. Additionally, A5 did not interfere with image interpretation in any patient.

CONCLUSION

Using all three dose reduction strategies during FLASH CTCA along with single-dose ivabradine administration ensures minimal radiation exposure in daily practice. In this study, A5 datasets had the best overall subjective and objective image quality despite their "plastic appearance". In the future, enhanced dose reduction can be obtained by further lowering tube voltages.

COVID-19-related cardiomyopathy: Can dual-energy computed tomography be a diagnostic tool?

BACKGROUND

No study on dual energy computed tomography (DECT) has been found in the literature to evaluate possibly fatal cardiac/myocardial problems in corona virus disease 2019 (COVID-19) patients. Myocardial perfusion deficits can be found in COVID-19 patients even without any significant coronary artery occlusion, and these deficits can be shown via DECT with a perfect interrater agreement.

AIM

To assess lung perfusion alterations in COVID-19 patients. To our knowledge, no study using DECT has been performed to evaluate possibly fatal cardiac/ myocardial problems in COVID-19 patients. The purpose of this study is to evaluate the role of DECT in the detection of COVID-19-related cardiac diseases.

METHODS

Two blinded independent examiners evaluated CT images using the 17-segment model according to the American Heart Association’s classification of the segmentation of the left ventricular myocardium. Additionally, intraluminal diseases and abnormalities in the main coronary arteries and branches were investigated. Following segment-by-segment analysis, perfusion deficiencies identified on the iodine map pictures on DECT were identified.

RESULTS

The study enrolled a total of 87 patients. Forty-two of these individuals were classified as COVID-19 positive, and 45 were classified as controls. Perfusion deficits were identified in 66.6% (n = 30) of the cases. All control patients had a normal iodine distribution map. Perfusion deficits were found on DECT iodine map images with subepicardial (n = 12, 40%), intramyocardial (n = 8, 26.6%), or transmural (n = 10, 33.3%) anatomical locations within the left ventricular wall. There was no subendocardial involvement in any of the patients.

CONCLUSION

Myocardial perfusion deficits can be found in COVID-19 patients even without any significant coronary artery occlusion. These deficits can be shown via DECT with a perfect interrater agreement. Additionally, the presence of perfusion deficit is positively correlated with D-dimer levels.

Evaluate of the effect of low tube voltage on the radiation dosage using 640-slice coronary CT angiography

BACKGROUND

640-slice coronary CT angiography is becoming an accurate and reliable method of diagnosing coronary heart disease. However, how to reduce the radiation dosage while ensuring the clinically acceptable image quality remains a quite challenging issue.

OBJECTIVE

To evaluate the effect of low tube voltage on radiation dosage under 640-slice coronary CT angiography (CCTA).

METHODS

Four hundred patients (236 males, 164 females) with coronary heart disease and underwent CCTA using DCVT were classified into A1 (tube voltage: 120 kV; exposure phase window: 30-80%), B1 (120 kV; 70-80%), A2 (100 kV; 30-80%) and B2 group (100 kV; 70-80%), respectively. Image qualities and effective dose (ED) were assessed and compared.

RESULTS

No significant differences were observed among the groups in terms of age, height, weight and body mass index (BMI) (P > 0.05). ED were significantly lower in 100 kV group (P < 0.05). CT values of coronary artery in 100 kV groups were 13.5% and 17.3% higher than 120 kV group. ED in B1 group were 64.5% and 67.0% lower than A1 group. ED in B2 group were 65.4% and 65.2% lower than A2 group.

CONCLUSION

When using a 640-slice CCTA prospective ECG-gating scanning mode, it is preferable to use a 100 kV tube voltage setting because compared to 120 kV tube voltage protocol, it seems to significantly decrease the mean effective radiation dose, without significantly lowering both the subjective and objective image quality.

A general framework of noise suppression in material decomposition for dual-energy CT

PURPOSE

As a general problem of dual-energy CT (DECT), noise amplification in material decomposition severely reduces the signal-to-noise ratio on the decomposed images compared to that on the original CT images. In this work, the authors propose a general framework of noise suppression in material decomposition for DECT. The method is based on an iterative algorithm recently developed in their group for image-domain decomposition of DECT, with an extension to include nonlinear decomposition models. The generalized framework of iterative DECT decomposition enables beam-hardening correction with simultaneous noise suppression, which improves the clinical benefits of DECT.

METHODS

The authors propose to suppress noise on the decomposed images of DECT using convex optimization, which is formulated in the form of least-squares estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-squares term. Analytical formulas are derived to compute the variance-covariance matrix for decomposed images with general-form numerical or analytical decomposition. As a demonstration, the authors implement the proposed algorithm on phantom data using an empirical polynomial function of decomposition measured on a calibration scan. The polynomial coefficients are determined from the projection data acquired on a wedge phantom, and the signal decomposition is performed in the projection domain.

RESULTS

On the Catphan(®)600 phantom, the proposed noise suppression method reduces the average noise standard deviation of basis material images by one to two orders of magnitude, with a superior performance on spatial resolution as shown in comparisons of line-pair images and modulation transfer function measurements. On the synthesized monoenergetic CT images, the noise standard deviation is reduced by a factor of 2-3. By using nonlinear decomposition on projections, the authors' method effectively suppresses the streaking artifacts of beam hardening and obtains more uniform images than their previous approach based on a linear model. Similar performance of noise suppression is observed in the results of an anthropomorphic head phantom and a pediatric chest phantom generated by the proposed method. With beam-hardening correction enabled by their approach, the image spatial nonuniformity on the head phantom is reduced from around 10% on the original CT images to 4.9% on the synthesized monoenergetic CT image. On the pediatric chest phantom, their method suppresses image noise standard deviation by a factor of around 7.5, and compared with linear decomposition, it reduces the estimation error of electron densities from 33.3% to 8.6%.

CONCLUSIONS

The authors propose a general framework of noise suppression in material decomposition for DECT. Phantom studies have shown the proposed method improves the image uniformity and the accuracy of electron density measurements by effective beam-hardening correction and reduces noise level without noticeable resolution loss.