Dynamic CT Perfusion Research Articles

Relationship between microvascular status and diagnostic performance of stress dynamic CT perfusion imaging.

This study aimed to investigate the relationship between microvascular status in the non-ischemic myocardium and the diagnostic performance of stress dynamic CT perfusion imaging (CTP) in detecting hemodynamically significant stenosis. This study included 157 patients who underwent coronary computed tomography angiography (CTA), CTP, and invasive coronary angiography (ICA), including fractional flow reserve (FFR). Hemodynamically significant stenosis was defined by FFR and ICA. A relative myocardial blood flow (MBF) for each myocardial segment was normalized to the highest MBF (remote MBF) among 16 segments. The receiver operating characteristic curve analysis for detecting hemodynamically significant stenosis at the vessel level indicated that patients with lower, intermediate, and higher remote MBF had areas under the curve (AUC) of 0.66, 0.70, and 0.80, respectively, for absolute MBF and AUCs of 0.63, 0.70, and 0.83, respectively, for relative MBF. The optimal cut-off values for absolute MBF were proportional to the levels of remote MBFs, while the ones for relative MBF were more consistent across lower to higher remote MBFs. For the patients with high remote MBF, the relative MBF demonstrated a sensitivity of 69%, specificity of 88%, and accuracy of 85% in detecting hemodynamically significant stenosis. The microvascular status in the non-ischemic myocardium influenced the diagnostic performance of dynamic CTP and threshold values of absolute MBFs, suggesting the potential preference for relative MBF over absolute MBF in clinical settings. Dynamic CTP's quantification of MBF offers the benefit of indicating reliability in ischemia detection relative to microvascular status. Question The relationship between microvascular status and diagnostic performance of dynamic CTP imaging has not been fully investigated. Findings The diagnostic performance of dynamic CTP and threshold values of absolute MBF were impacted by microvascular status. Clinical relevance The differences in diagnostic accuracy of dynamic CTP related to varying remote MBF values necessitate a personalized evaluation of myocardial perfusion in dynamic CTP images.

Adaptive prior image constrained total generalized variation for low-dose dynamic cerebral perfusion CT reconstruction

BACKGROUND: Dynamic cerebral perfusion CT (DCPCT) can provide valuable insight into cerebral hemodynamics by visualizing changes in blood within the brain. However, the associated high radiation dose of the standard DCPCT scanning protocol has been a great concern for the patient and radiation physics. Minimizing the x-ray exposure to patients has been a major effort in the DCPCT examination. A simple and cost-effective approach to achieve low-dose DCPCT imaging is to lower the x-ray tube current in data acquisition. However, the image quality of low-dose DCPCT will be degraded because of the excessive quantum noise. OBJECTIVE: To obtain high-quality DCPCT images, we present a statistical iterative reconstruction (SIR) algorithm based on penalized weighted least squares (PWLS) using adaptive prior image constrained total generalized variation (APICTGV) regularization (PWLS-APICTGV). METHODS: APICTGV regularization uses the precontrast scanned high-quality CT image as an adaptive structural prior for low-dose PWLS reconstruction. Thus, the image quality of low-dose DCPCT is improved while essential features of targe image are well preserved. An alternating optimization algorithm is developed to solve the cost function of the PWLS-APICTGV reconstruction. RESULTS: PWLS-APICTGV algorithm was evaluated using a digital brain perfusion phantom and patient data. Compared to other competing algorithms, the PWLS-APICTGV algorithm shows better noise reduction and structural details preservation. Furthermore, the PWLS-APICTGV algorithm can generate more accurate cerebral blood flow (CBF) map than that of other reconstruction methods. CONCLUSIONS: PWLS-APICTGV algorithm can significantly suppress noise while preserving the important features of the reconstructed DCPCT image, thus achieving a great improvement in low-dose DCPCT imaging.

Performance Of A Diagnostic Algorithm Based On Cardiac Computed Tomography Angiography And Dynamic Computed Tomography Perfusion In Symptomatic Patients With Intermediate To High Pretest Risk Of Coronary Artery Disease Or History Of Chronic Coronary Syndrome

Performance Of A Diagnostic Algorithm Based On Cardiac Computed Tomography Angiography And Dynamic Computed Tomography Perfusion In Symptomatic Patients With Intermediate To High Pretest Risk Of Coronary Artery Disease Or History Of Chronic Coronary Syndrome

Comparison Of Quantitative Myocardial Blood Flow Acquired During Dynamic Stress Ct Perfusion Against Stress Cmr Perfusion

Comparison Of Quantitative Myocardial Blood Flow Acquired During Dynamic Stress Ct Perfusion Against Stress Cmr Perfusion

Value of Dynamic Computed Tomography Myocardial Perfusion in CAD: A Systematic Review and Meta-analysis.

Dynamic stress computed tomography (CT) perfusion is a non-invasive method for quantifying myocardial ischemia by assessing myocardial blood flow (MBF). In this meta-analysis, we evaluated the diagnostic accuracy of dynamic CT perfusion for the detection of significant coronary artery disease (CAD) across various CT scanners, obese patients, and its prognostic value. We systematically searched PubMed, Embase, Web of Science, and Cochrane library for published studies evaluating the accuracy of CT myocardial perfusion in diagnosing functional significant ischemia by invasive fractional flow reserve. The diagnostic performance of dynamic CT perfusion in detecting ischemia was evaluated using a summary receiver operating characteristic (sROC) curve. A total of 23 studies underwent meta- analysis. In myocardial region without ischemia, MBF was measured at 1.44 ml/min/g (95% confidence interval [CI]: 1.13-1.75), while in region with ischemia, it was 0.94 ml/min/g (95% CI: 0.80-1.08) (p<0.001). On the patient-based analysis, the area under the sROC curve of CT-MBF was 0.93, with a sensitivity of 0.84 and specificity of 0.88. Differences in CT type (dual source vs. single source), and body mass index (BMI) did not significantly affect the diagnostic performance. The pooled hazard ratio of dynamic CT perfusion for predicting adverse events was 4.98 (95%CI: 2.08-11.93, p=<0.001, I2=61%, p for heterogeneity = 0.07). Dynamic CT perfusion has high diagnostic performance in the quantitative assessment of ischemia and detection of functional myocardial ischemia as defined by invasive FFR, and may be useful in risk stratification of CAD patients.

Radiation dose reduction of 50% in dynamic myocardial CT perfusion with skipped beat acquisition: a retrospective study.

Dynamic myocardial computed tomography perfusion (CTP) is a novel imaging technique that increases the applicability of CT for cardiac imaging; however, the scanning requires a substantial radiation dose. To investigate the feasibility of dose reduction in dynamic CTP by comparing all-heartbeat acquisitions to periodic skipping of heartbeats. We retrieved imaging data of 38 dynamic CTP patients and created new datasets with every fourth, third or second beat (Skip1:4, Skip1:3, Skip1:2, respectively) removed. Seven observers evaluated the resulting images and perfusion maps for perfusion deficits. The mean blood flow (MBF) in each of the 16 myocardial segments was compared per skipped-beat level, normalized by the respective MBF for the full dose, and averaged across patients. The number of segments/cases whose MBF was <1.0 mL/g/min were counted. Out of 608 segments in 38 cases, the total additional number of false-negative (FN) segments over those present in the full-dose acquisitions and the number of additional false-positive cases were shown as acquisition (segment [%], case): Skip1:4: 7 (1.2%, 1); Skip1:3: 12 (2%, 3), and Skip1:2: 5 (0.8%, 2). The variability in quantitative MBF analysis in the repeated analysis for the reference condition resulted in 8 (1.3%) additional FN segments. The normalized results show a comparable MBF across all segments and patients, with relative mean MBFs as 1.02 ± 0.16, 1.03 ± 0.25, and 1.06 ± 0.30 for the Skip1:4, Skip1:3, and Skip1:2 protocols, respectively. Skipping every second beat acquisition during dynamic myocardial CTP appears feasible and may result in a radiation dose reduction of 50%. Diagnostic performance does not decrease after removing 50% of time points in dynamic sequence.

Contrast Agent Dynamics Determine Radiomics Profiles in Oncologic Imaging.

The reproducibility of radiomics features extracted from CT and MRI examinations depends on several physiological and technical factors. The aim was to evaluate the impact of contrast agent timing on the stability of radiomics features using dynamic contrast-enhanced perfusion CT (dceCT) or MRI (dceMRI) in prostate and lung cancers. Radiomics features were extracted from dceCT or dceMRI images in patients with biopsy-proven peripheral prostate cancer (pzPC) or biopsy-proven non-small cell lung cancer (NSCLC), respectively. Features that showed significant differences between contrast phases were identified using linear mixed models. An L2-penalized logistic regression classifier was used to predict class labels for pzPC and unaffected prostate regions-of-interest (ROIs). Nine pzPC and 28 NSCLC patients, who were imaged with dceCT and/or dceMRI, were included in this study. After normalizing for individual enhancement patterns by defining seven individual phases based on a reference vessel, 19, 467 and 128 out of 1204 CT features showed significant temporal dynamics in healthy prostate parenchyma, prostate tumors and lung tumors, respectively. CT radiomics-based classification accuracy of healthy and tumor ROIs was highly dependent on contrast agent phase. For dceMRI, 899 and 1027 out of 1118 features were significantly dependent on time after contrast agent injection for prostate and lung tumors. CT and MRI radiomics features in both prostate and lung tumors are significantly affected by interindividual differences in contrast agent dynamics.

Diagnostic accuracy of computed tomography brain perfusion in the prediction of acute ischemic stroke taking the findings of MRI as gold standard.

Objectives: To determine the diagnostic accuracy of computed tomography brain perfusion to predict acute ischemic stroke taking the findings of MRI as gold standard. Study Design: Cross-sectional Validation study. Setting: Department of Radiology Allied Hospital Faisalabad. Period: 20th May 2022 to 19th November 2022. Material &amp; Methods: A total of 215 individuals, aged between 30 and 70, of both sexes, and exhibiting ischemic stroke symptoms lasting no more than 12 hours, were included. Patients with abnormal renal function tests having renal disease were excluded. The conventional non-contrast CT used in the CT stroke protocol had basal sections that were either 3 mm or 4 mm in thickness and supra tentorial sections that were either 3 mm or 4 mm in thickness. The acquisition parameters were 80kVp and 120mAs. Dynamic CT perfusion was carried out with 4 cm plane coverage. At the seventh day, all patients underwent a follow-up MRI using a 1.5 Tesla Philips MRI scanner. A radiologist examined CTP to look for signs of early ischemic changes. For CT perfusion (CTP), measurements were taken for time to peak (TTP), cerebral blood flow (CBF), and cerebral blood volume (CBV). Results: Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of computed tomography brain perfusion in the prediction of acute ischemic stroke taking the findings of MRI as gold standard was 85.37%, 76.09%, 82.68%, 79.55% and 81.40% respectively. Conclusion: This study led to the conclusion that diagnostic accuracy of computed tomography brain perfusion to predict acute ischemic stroke is quite high.

Normal values of myocardial blood flow measured with dynamic myocardial CT perfusion.

Dynamic myocardial CT perfusion (DM-CTP) can, in combination with coronary CT angiography (CCTA), provide anatomical and functional evaluation of coronary artery disease (CAD). However, normal values of myocardial blood flow (MBF) are needed to identify impaired myocardial blood supply in patients with suspected CAD.We aimed to establish normal values for MBF measured using DM-CTP, to assess the effects of age and sex, and to assess regional distribution of MBF. A total of 82 healthy individuals (46 women) aged 45-78 years with normal coronary arteries by CCTA underwent either rest and adenosine stress DM-CTP (n = 30) or adenosine induced stress DM-CTP only (n = 52). Global and segmental MBF were assessed. Global MBF at rest and during stress were 0.93 ± 0.42 mL/min/g and 3.58 ± 1.14 mL/min/g respectively. MBF was not different between the sexes (P = 0.88 at rest and P = 0.61 during stress) and no correlation was observed between MBF and age (P = 0.08 at rest and P = 0.82 during stress). Among the 16 myocardial segments, significant inter-segmental differences were found (P < 0.01), which was not related to age, sex or coronary dominance. Myocardial blood flow assessed by DM-CTP in healthy individuals with normal coronary arteries displays significant intersegmental heterogeneity which does not seem to be affected by age, sex or coronary dominance. Normal values of myocardial blood flow may be helpful in the clinical evaluation of suspected myocardial ischemia using DM-CTP.

Computed tomography perfusion or fractional flow reserve–computed tomography to assess the significance of stenosis: Literature review

Abstract Detection of myocardial ischemia based on detection and grading of myocardial perfusion is a cornerstone of coronary artery disease (CAD) diagnosis. Coronary CT angiography (CCTA) is a recognized imaging test for exclusion of anatomically significant coronary stenosis in patients with low or moderate probability of CAD, but gives no information on its physiological significance. The two major approaches to evaluate the presence of induced myocardial ischemia using CT, static or dynamic perfusion CT (CTP) or non-invasive fractional flow reserve analysis (FFRCT), have been validated in multiple single- and multi-center studies with comparable results of high sensitivity, specificity and accuracy. Several studies with head-to-head comparison of CTP and FFRCT using invasive FFR measurement as a reference standard showed a slight superiority of CTP, especially in groups of patients with the borderline values of FFR-CT. The principle of myocardial perfusion assessment with CTP looks more physiological than computation models used in FFR-CT. However, the best results were shown by combined use of CCTA, CTP and FFRCT, providing the integrated anatomical and physiological information. Technical advances in CT technique, artificial intelligence and machine learning, together with accumulation of new clinical evidence, will result in development of the best strategy for comprehensive assessment of both coronary anatomy and myocardial perfusion with help of cardiac CT.

Feasibility of four-dimensional similarity filter for radiation dose reduction in dynamic myocardial computed tomography perfusion imaging.

We aimed to evaluate the impact of four-dimensional noise reduction filtering using a four-dimensional similarity filter (4D-SF) on radiation dose reduction in dynamic myocardial computed tomography perfusion (CTP). Forty-three patients who underwent dynamic myocardial CTP using 320-row computed tomography (CT) were included in the study. The original images were reconstructed using iterative reconstruction (IR). Three different CTP datasets with simulated noise, corresponding to 25%, 50%, and 75% reduction of the original dose (300 mA), were reconstructed using a combination of IR and 4D-SF. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed, and CT-derived myocardial blood flow (CT-MBF) was quantified. The results were compared between the original and simulated images with radiation dose reduction. The median SNR (first quartile-third quartile) at the original, 25%-, 50%-, and 75%-dose reduced-simulated images with 4D-SF was 8.3 (6.5-10.2), 16.5 (11.9-21.7), 15.6 (11.0-20.1), and 12.8 (8.8-18.1) and that of CNR was 4.4 (3.2-5.8), 6.7 (4.6-10.3), 6.6 (4.3-10.1), and 5.5 (3.5-9.1), respectively. All the dose-reduced-simulated CTPs with 4D-SF had significantly higher image quality scores in SNR and CNR than the original ones (25%-, 50%-, and 75%-dose reduced vs. original images, p < 0.05, in each). The CT-MBF in 75%-dose reduced-simulated CTP was significantly lower than 25%-, 50%- dose-reduced-simulated, and original CTPs (vs. 75%-dose reduced-simulated images, p < 0.05, in each). 4D-SF has the potential to reduce the radiation dose associated with dynamic myocardial CTP imaging by half, without impairing the robustness of MBF quantification.

Dynamic CT Myocardial Perfusion: The Role of Functional Evaluation in the Diagnosis of Coronary Artery Disease.

Coronary computed tomography angiography (CTA) is a widely accepted, non-invasive diagnostic modality for the evaluation of patients with suspected coronary artery disease (CAD). However, a limitation of CTA is its inability to provide information on the hemodynamic significance of the coronary lesion. The recently developed stress dynamic CT perfusion technique has emerged as a potential solution to this diagnostic challenge. Dynamic CT myocardial perfusion provides information on the hemodynamic consequences of coronary stenosis and is used to detect myocardial ischemia. The combination of stress dynamic CT myocardial perfusion with CTA provides a comprehensive assessment that integrates anatomical and functional information. CT myocardial perfusion has been validated in several clinical studies and has shown comparable accuracy to Positron Emission Tomography (PET) and stress magnetic resonance imaging (MRI) in the diagnosis of hemodynamically significant coronary stenosis and superior performance to Single Photon Emission Computed Tomography (SPECT). More importantly, CTP-derived myocardial perfusion has been shown to have a strong correlation with FFR, and the use of CTP results in a reduction of negative catheterizations. In the context of suspected stable coronary artery disease, the CT protocol with dynamic perfusion imaging combined with CTA eliminates the need for additional testing, making it a convenient "one-stop-shop" method and an effective gatekeeper to an invasive approach.

Dynamic Perfusion Computed Tomography for the Assessment of Concomitant Coronary Artery Disease in Patients with a History of Percutaneous Transluminal Angioplasty for Chronic Limb-Threatening Ischemia-A Pilot Study.

Chronic limb-threatening ischemia (CLTI) is associated with high rates of long-term cardiovascular mortality. Exercise stress testing to detect obstructive coronary artery disease (CAD) can be difficult in this subset of patients due to inability to undergo exercise testing, presence of balanced ischemia and severe coronary artery calcification (CAC). To test the feasibility of regadenoson stress dynamic perfusion computed tomography (DPCT) in CLTI patients. Between 2018 and 2023, coronary computed tomography angiography (CTA) and, in the case of a calcium score higher than 400, DPCT, were performed in 25 CLTI patients with a history of endovascular revascularization. Of the 25 patients, 19 had a calcium score higher than 400, requiring DPCT image acquisition. Obstructive CAD could be ruled out in 10 of the 25 patients. Of the 15 CTA/DPCT+ patients, 13 proceeded to coronary angiography (CAG). Revascularization was necessary in all 13 patients. In these 13 patients, vessel-based sensitivity and specificity of coronary CTA/DPCT as compared to invasive evaluation was 75%, respectively. At follow-up (27 ± 21 months) there was no statistically significant difference in all-cause mortality between CTA/DPCT- positive and -negative patients (p = 0.065). Despite a high prevalence of severe CAC, coronary CTA complemented by DPCT may be a feasible method to detect obstructive and functionally significant CAD in CLTI patients.

Stress-only dynamic computed tomography perfusion protocol (CTP) alone without computed tomography coronary angiography (CCTA) has limited specificity to diagnose ischemia: A retrospective two-center study

PurposeTo investigate diagnostic performance of stress-only dynamic myocardial computed tomography perfusion (CTP) without computed tomography coronary angiography (CCTA) to diagnose ischemia with invasive fractional flow reserve (FFR) as a reference standard. Method135 datasets (68 positive for ischemia with invasive FFR < 0.8) acquired with a 256-slice CT system (Revolution, GE Healthcare, Chicago, IL, USA) were retrieved, postprocessed with a deep learning-based algorithm (Advanced intelligent Clear-IQ Engine (AiCE), Canon Medical Systems, Otawara, Japan) (FC03/cardiac kernel, 8 mm slice thickness), analyzed using a dedicated workstation (Vitrea research 7.11.0. Vital Images, Minnetonka, MN, USA), and loaded into a clinical workstation (CardIQ, GE Healthcare, Chicago, IL, USA) for review. Ten observers with various experience from two research sites evaluated the post-processed images, perfusion slices and maps to indicate presence vs absence of perfusion defect and its probability (five-point Likert scale). Binary decisions and probability scores were used to calculate sensitivity and specificity for each reader, and to create receiver operating characteristics (ROC) curves, respectively. Furthermore, the correlation coefficient (ICC) was computed. ROC AUC of a purely quantitative analysis was obtained thanks to a color-coded map with a fixed scale superimposed on myocardial walls displaying myocardial blood flow (MBF) values. ResultsThe overall case-based sensitivity and specificity for the detection of perfusion deficit were 0.79 and 0.30, respectively. No significant differences were detected in the AUC across readers (p value = 0.66). The AUC values were 0.50, 0.58, 0.63, 0.59, 0.45, 0.60, 0.56, 0.61, 0.52, 0.61. Absolute reader agreement ICC was 0.60 (good agreement) for an average case. ConclusionDynamic CTP alone has good sensitivity, but low specificity when analyzed without CCTA. These findings reinforce the need to guide the interpretation functional test with the knowledge of coronary artery anatomy.

Low-dose dynamic cerebral perfusion CT reconstruction based on voxel-level TAC correction (VTC)

Dynamic cerebral perfusion computed tomography (DCP-CT) is an advanced imaging technique that helps in the clinical diagnosis of cerebrovascular diseases (CVDs). However, radiation dose deposition during repeated CT scans seriously limits its clinical application. Effective DCP-CT imaging method based on low-dose protocol is needed. A regularized least-squares method with high interpretability based on voxel-level time-attenuation curve (TAC) correction (VTC) is proposed in this study for low-dose DCP-CT image reconstruction. The theory of third-order Hermite interpolation (THI) is applied to voxel-level TAC correction during dynamic images reconstruction. The peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) are used to quantitatively evaluate the proposed method in terms of imaging accuracy and noise reduction, while hemodynamic maps, including cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transition time (MTT), are calculated to validate its ability to restore hemodynamic parameters. It is proven that the proposed VTC method for low-dose DCP-CT imaging has better performance than several state-of-the-art dynamic CT imaging methods. It can be expected that the VTC method can play an important role in the promotion of the clinical application of DCP-CT for the diagnosis of CVD.

Diagnostic Accuracy Of Dynamic Stress Myocardial Ct Perfusion As Compared With Invasive Coronary Physiology Assessment In Patients With Suspected In-stent Restenosis Or Cad Progression: Results Of Advantage 2 Study

Diagnostic Accuracy Of Dynamic Stress Myocardial Ct Perfusion As Compared With Invasive Coronary Physiology Assessment In Patients With Suspected In-stent Restenosis Or Cad Progression: Results Of Advantage 2 Study

Myocardial Fibrosis Increases False Positive Results In Dynamic Stress CT Perfusion Compared To Cardiac MR Imaging

Myocardial Fibrosis Increases False Positive Results In Dynamic Stress CT Perfusion Compared To Cardiac MR Imaging

Evaluation and timing optimization of CT perfusion first pass analysis in comparison to maximum slope model in pancreatic adenocarcinoma

For implementation, performance evaluation and timing optimization of CT perfusion first pass analysis (FPA) by correlation with maximum slope model (MSM) in pancreatic adenocarcinoma, dynamic CT perfusion acquisitions of 34 time-points were performed in 16 pancreatic adenocarcinoma patients. Regions of interest were marked in both parenchyma and carcinoma. FPA, a low radiation exposure CT perfusion technique, was implemented. Blood flow (BF) perfusion maps were calculated using FPA and MSM. Pearson’s correlation between FPA and MSM was calculated at each evaluated time-point to determine optimum timing for FPA. Differences in BF between parenchyma and carcinoma were calculated. Average BF for MSM was 106.8 ± 41.5 ml/100 ml/min in parenchyma and 42.0 ± 24.8 ml/100 ml/min in carcinoma, respectively. For FPA, values ranged from 85.6 ± 37.5 ml/100 ml/min to 117.7 ± 44.5 ml/100 ml/min in parenchyma and from 27.3 ± 18.8 ml/100 ml/min to 39.5 ± 26.6 ml/100 ml/min in carcinoma, depending on acquisition timing. A significant difference (p value < 0.0001) between carcinoma and parenchyma was observed at all acquisition times based on FPA measurements. FPA shows high correlation with MSM (r > 0.90) and 94% reduction in the radiation dose compared to MSM. CT perfusion FPA, where the first scan is obtained after the arterial input function exceeds a threshold of 120 HU, followed by a second scan after 15.5–20.0 s, could be used as a potential imaging biomarker with low radiation exposure for diagnosing and evaluating pancreatic carcinoma in clinical practice, showing high correlation with MSM and the ability to differentiate between parenchyma and carcinoma.

Computed tomography perfusion and angiography in patients with chronic total occlusion undergoing percutaneous coronary intervention

Background and aimsMyocardial perfusion imaging (MPI) and anatomical imaging with coronary computed tomography angiography (CCTA) can play an important role in the preprocedural planning of a chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We aimed to establish the feasibility of a novel dynamic computed tomography perfusion (CTP) analysis for the assessment of myocardial perfusion before and after a successful recanalization of CTO in patients undergoing CCTA as part of a standard preprocedural workup. MethodsIn a prospective observational study symptomatic patients underwent dynamic CTP on a dual-source CT scanner both before and 3 months after successful CTO PCI. ResultsTwenty-seven patients completed the study (63 ± 8 years old, 78% male). Following successful CTO PCI, there was a significant reduction in the ischemic burden (5 [5–7] versus 1 [0–2] segments, p < 0.001), and improvement in myocardial blood flow (85.3 [71.7–94.1] versus 134.6 [123.8–156.9] mL/min, p < 0.001) resulting in an increase in the relative flow reserve (0.49 [0.41–0.57] versus 0.88 [0.74–0.95], p < 0.001). ConclusionsCTP emerges as a robust and safe method for MPI in CTO patients. The single imaging session assessment of both coronary anatomy and perfusion with CT lends itself to precise disease phenotyping in the challenging population of CTO patients.

Diagnostic accuracy of dynamic stress myocardial ct perfusion as compared with invasive coronary physiology assessment in patients with suspected ISR or CAD progression: results of ADVANTAGE II study

Abstract Funding Acknowledgements Type of funding sources: None. Objectives To compare the diagnostic performance of regadenosone-stress dynamic myocardial perfusion assessed by CT (CTP) as compared with that of coronary CT angiography (CCTA) alone by using invasive fractional flow reserve (FFR) and index of microvascular resistance (IMR) as standard of reference. Background Diagnostic performance of CCTA for in-stent restenosis (ISR) detection is still challenging. Recently, CTP demonstrated additional specificity and diagnostic accuracy over CCTA alone in patients with previous stent implantation and suspected IRS or progression of coronary artery disease (CAD). However, no data are available in this clinical setting on the performance of CTP by using a new technique allowing for a non-invasive adjudication of regional myocardial blood flow (Dynamic CTP) and to assess both macrovascular and microvascular disease status. Methods We enrolled consecutive stable patients with previous coronary stenting referred for invasive quantitative coronary angiography (QCA) for clinical indication. All patients underwent dynamic stress myocardial CTP and rest CTP+CCTA by using a last generation scanner characterized by a 16-cm Z-axis coverage and fast (0.28 sec) gantry rotation time. Invasive FFR and IMR were performed during QCA according to the standard practice. The diagnostic rate and diagnostic accuracy of CCTA and CTP were evaluated in a territory-based analyses vs. FFR, IMR (primary endpoint of the study) and QCA (secundary endpoint). Results In 156 enrolled patients (126 men, mean age 63.1±8.2 years), the diagnostic rate (number of territories interpretable/number of territories evaluated) of CTP was significantly higher than that of CCTA (789/799=98.7% vs. 764/799=95.6%; p = 0.0002). The mean absolute MBF values for ischemic territories (pathological FFR and/or IMR) was significantly lower as compared with those for normal territories (96 ± 32 ml/100 g/min vs. 130 ± 46 ml/100 g/min; p&amp;lt; 0.0001). When FFR was used as gold standard, sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of CTP were higher than those of CCTA (89%, 82.8%, 69.2%, 94.6% and 84.7% vs. 60%, 61.9%, 31.9%, 83.8% and 61.5%, p&amp;lt;0.001, respectively). When IMR was used as gold standard, sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of CTP were higher than those of CCTA (76.5%, 85.9%, 72.2%, 88.4% and 82.9% vs. 48.2%, 63.5%, 33.3%, 76.4% and 59.3%, p&amp;lt;0.01, respectively). When the presence of at least one abnormal physiological parameter among FFR and IMR was used as gold standard, the diagnostic accuracy of CTP was higher than that of CCTA (90.8% vs. 68.1%, p&amp;lt;0.001). The mean ED of the total CCTA/rest CTP/stress CTP was 5.63±4.2 mSv. Conclusion In patients with coronary stents, dynamic CTP significantly improves diagnostic rate and accuracy of CCTA alone in comparison with both FFR and IMR.