Research Presentation Session

RPS 203 - Myocardial perfusion imaging and infarct characterisation: diagnosis and prognosis

Lectures

1
RPS 203 - Improved sensitivity in diagnosing myocardial infarction using frequency selective nonlinear blending in computed tomography

RPS 203 - Improved sensitivity in diagnosing myocardial infarction using frequency selective nonlinear blending in computed tomography

05:40Eva Stock, Tübingen / DE

Purpose:

To evaluate the effect of frequency selective nonlinear blending (NLB) on the detectability of clinically suspected myocardial infarction in computed tomography (CT) images.

Methods and materials:

A retrospective patient search in our institution’s PACS yielded 32 patients with myocardial infarction who underwent both contrast-enhanced CT (CECT) and invasive coronary angiography (ICA) between 2015 and 2019. ICA was used as a standard of reference. NLB was applied to CECT images, which were obtained in the portal-venous phase. Two readers independently determined optimal NLB settings and independently rated image quality (equidistant Likert). Objective image quality was determined using a ROI-based calculation of contrast-to-noise ratios (CNR). The acquired data was statistically compared between CECT and NLB using non-parametric tests. Interobserver agreement was calculated using kappa statistics.

Results:

On average, a centre of 110 HU, a delta of 20 HU, and a slope of 5 resulted in the best overall delineation of hypodense areas of myocardial infarction. Averaged CNR of myocardial infarctions could be significantly increased using NLB (CECT:5,73 [2,88;12,83];NLB:11,28[6,56;23,19];p<0,0001). Interobserver agreement showed substantial agreement (kappa: 0,70). Subjective image quality was significantly higher for NLB CT images in comparison with CECT images (CECT:2 [2;2],NLB:4 [3;4],p<0,0001).

Conclusion:

This pilot study demonstrated that frequency selective nonlinear blending of CECT images allows a significant improvement of the delineation of myocardial infarction. Further clinical studies are warranted in order to validate these initial results.

Limitations:

A small study population.

Ethics committee approval

This study was approved by our local ethics committee.

Funding:

No funding was received for this work.

2
RPS 203 - The prognostic value of the myocardial salvage index measured by magnetic resonance imaging after ST-segment elevation myocardial infarction: a systematic review and meta-regression analysis

RPS 203 - The prognostic value of the myocardial salvage index measured by magnetic resonance imaging after ST-segment elevation myocardial infarction: a systematic review and meta-regression analysis

04:59B. Kendziora, Berlin / DE

Purpose:

To summarise published data on the prognostic value of the proportion of salvaged myocardium inside previously ischaemic myocardium (myocardial salvage index) measured by T2-weighted and T1-weighted late gadolinium enhancement magnetic resonance imaging (MRI) after ST-segment elevation myocardial infarction (STEMI).

Methods and materials:

We systematically searched for studies stating both the myocardial salvage index measured by T2-weighted and T1-weighted late gadolinium enhancement MRI after STEMI and the incidence of major cardiac events (MACE) during follow-up, defined as cardiac death, nonfatal myocardial infarction, or admission for heart failure. Random and mixed effects models were used for data analysis.

Results:

The search revealed 10 studies with 2,697 patients. The pooled myocardial salvage index, calculated as the proportion of nonnecrotic myocardium inside edematous myocardium measured by T2-weighted and T1-weighted late gadolinium enhancement MRI after STEMI, was 43.0% (95% confidence interval [CI]: 37.4, 48.6). The pooled length of follow-up was 12.3 months (95 % CI: 7.0, 17.6). The pooled incidence of MACE during follow-up was 10.6 % (95% CI: 5.7, 15.5). With every 1% increase in the myocardial salvage index, there was an absolute decrease of 1.7% in the incidence of MACE during follow-up (95 % CI: 1.6, 1.9). Heterogeneity between studies was considerable (τ = 21.3).

Conclusion:

An analysis of the published data suggests that the myocardial salvage index measured by T2-weighted and T1-weighted late gadolinium enhancement MRI after STEMI provides prognostic information on the risk of MACE. However, there is considerable heterogeneity between studies.

Limitations:

In consequence of the heterogeneity between studies, exact thresholds of the myocardial salvage index for low or high risk of MACE cannot be provided.

Ethics committee approval

n/a

Funding:

We acknowledge support from the German Research Foundation and the Open Access Publication Fund of Charité - Universitätsmedizin Berlin.

3
RPS 203 - A comparison of iodine distribution characteristics in rest and stress first-pass perfusion of healthy myocardium as obtained by a dual-layer CT scanner

RPS 203 - A comparison of iodine distribution characteristics in rest and stress first-pass perfusion of healthy myocardium as obtained by a dual-layer CT scanner

06:28S. Boccalini, Bron / FR

Purpose:

To compare iodine distribution in healthy myocardium at first-pass perfusion imaging between stress and rest acquisitions using dual-layer CT (DLCT).

Methods and materials:

Between May 2019 and September 2019, patients undergoing coronary-CT for typical thoracic pain without troponin elevation and patients with borderline stenosis at coronary CT underwent an additional CT acquisition after pharmacological stress. Both exams were performed on a DLCT. The injection protocols were 50mL of contrast material at 5mL/sec at rest 35mL in patients <80kg and 0.5mL/kg in patients >80 kg (maximum 45mL) at 2.5mL/sec under stress. Patients with coronary stenosis >50% and/or with positive invasive FFR were excluded. Regions-of-interest were manually drawn on the 16 AHA myocardial segments. Iodine concentration was measured on iodine-maps in mg/mL.

Results:

224 segments (112 rest/112 stress of the same patients) were analysed. No significant difference in iodine concentration was found between rest (median=1.48mg/mL; IQR=0.44) and stress (median=1.44mg/mL; IQR=0.53) (p=0.4). At rest, a significant difference between coronary territories was demonstrated (p=0.02; highest values in the territory of the circumflex (median=1.66mg/mL; IQR=0.49). After stress iodine concentration was homogeneous in different coronary territories (p=0.2). The difference of iodine values between rest and stress was not significantly different in the 16 segments (p=0.94) nor in coronary territories (p=0.37).

Conclusion:

In healthy myocardium, significant differences between coronary territories were shown at rest but not after stress, probably because of different injection protocols. Therefore, an injection protocol with a low dose and slow flow is preferable to evaluate myocardial perfusion after pharmacological stress. The difference between rest and stress iodine values of healthy myocardium was homogeneous, without focal reduction of iodine content.

Limitations:

Few patients.

Ethics committee approval

n/a

Funding:

No funding was received for this work.

4
RPS 203 - Sequential strategy including FFRCT plus stress-CTP impacts on the management of patients with stable chest pain: the stress-CTP RIPCORD study

RPS 203 - Sequential strategy including FFRCT plus stress-CTP impacts on the management of patients with stable chest pain: the stress-CTP RIPCORD study

06:57G. Muscogiuri, Milan / IT

Purpose:

Stress computed tomography perfusion (Stress-CTP) and CT-derived fractional flow reserve (FFRCT) are functional techniques that can be added to coronary CT angiography (cCTA) to improve management of patients with suspected coronary artery disease (CAD).

We sought to determine impact of FFRCT and Stress-CTP added to cCTA on management of patients with suspected CAD.

Methods and materials:

Patients scheduled for invasive coronary angiography (ICA) were evaluated with cCTA, FFRCT, and stress-CTP. A management plan defined as optimal medical therapy (OMT) or revascularisation was recorded for the following strategies: cCTA alone, cCTA+FFRCT, cCTA+stress-CTP, and cCTA+FFRCT+stress-CTP. These strategies were then compared with the clinical decision based on ICA plus invasive FFR. Endpoints for each strategy were overall evaluability, effective radiation dose (ED), rate of reclassification, agreement with therapeutic decision making, and the rate of agreement in terms of vessels to be revascularised.

Results:

291 consecutive patients were enrolled. cCTA alone, cCTA+FFRCT, cCTA+stress-CTP, and cCTA+FFRCT+stress-CTP showed similar evaluability (91%, 89%, 90%, and 87%, respectively) and a similar rate of reclassification of cCTA findings when FFRCT and stress-CTP were added (28% and 34%, respectively). cCTA, cCTA+FFRCT, cCTA+stress-CTP, and cCTA+FFRCT+stress-CTP showed a rate of agreement versus the final therapeutic decision and a rate of agreement in terms of vessels to be revascularised of 63%, 71%, 89%, and 84% (cCTA+stress-CTP and cCTA+FFRCT+stress-CTP vs cCTA and cCTA+FFRCT:p<0.01), and 57%, 64%, 74%, and 71% (cCTA+stress-CTP and cCTA+FFRCT+stress-CTP vs cCTA and cCTA+FFRCT:p<0.01), respectively, with an ED of 2.9±1.3mSv, 2.9±1.3mSv, 5.9±2.7mSv, and 3.1±2.1mSv (cCTA+FFRCT+stress-CTP vs cCTA+stress-CTP:p<0.001).

Conclusion:

The addition of functional assessment with FFRCT and stress-CTP provides incremental therapeutic decision-making value compared to cCTA alone. Sequential strategy with cCTA+FFRCT+stress-CTP is associated with the best compromise in terms of clinical impact and radiation exposure.

Limitations:

A single-centre study.

Ethics committee approval

Ethical committee registration number:R250/15-CCM262.

Funding:

Grant from General Electric.

5
RPS 203 - Invisible to the eye: radiomics revealing alterations in apparently healthy myocardial tissue of patients with ischemic disease

RPS 203 - Invisible to the eye: radiomics revealing alterations in apparently healthy myocardial tissue of patients with ischemic disease

03:42A. Cavaliere, Padua / IT

Purpose:

To characterise by radiomic analyses the healthy myocardial tissue (i.e. without any visual alteration at MR imaging) of patients with ischaemic and non-ischaemic myocardial disease.

Methods and materials:

Patients with ischaemic and non-ischaemic disease who underwent a contrast-enhanced cardiac MR from January 2018 to September 2019 were included in this retrospective study. One radiologist expert in cardiovascular imaging, blind to the clinical information, applied a 5 mm standardised region of interest (i.e. using the phase-sensitive inversion recovery images) on the healthy myocardial tissue of each patient and on the myocardium of 10 controls (patients without myocardial infarction) using a 3D Slicer. 56 radiomic features belonging to three categories were extracted: first-order statistics (FOS), grey-level co-occurrence matrix (GLCM), and grey-level run-length matrix (GLRLM). One-way repeated-measures analysis of variance (ANOVA) with Greenhouse-Geisser correction and Bonferroni post hoc tests were used to evaluate the differences among all datasets (p<0.05).

Results:

10 patients with ischaemic injury (1 female; mean age 60.6 ±10.8 yrs), 11 with non-ischaemic infarction (3 females, mean age 51.8 ±21.4), and 10 controls (3 females, mean age 35.1 ±15.1) were examined. For 25/56 investigated features, the myocardium of the ischaemic patients differed from that of the non-ischaemic patients and controls (4 FOS, 13 GLCM, and 8 GLRLM features; p<0.05 each). No statistically significant differences emerged between the non-ischaemic patients and the controls for any of the examined variables (p>0.05, each).

Conclusion:

Radiomic analyses suggest that ischaemic injuries also affect myocardial tissue visually healthy on MR imaging.

Limitations:

Further studies including a larger population and a longitudinal approach are necessary to fully address this evidence and its clinical implications.

Ethics committee approval

Ethics committee approval obtained.

Funding:

No funding was received for this work.

6
RPS 203 - A comparison of qualitative tagging and late gadolinium enhancement with PET- CT in the evaluation of myocardial viability

RPS 203 - A comparison of qualitative tagging and late gadolinium enhancement with PET- CT in the evaluation of myocardial viability

05:41M. Moideenbawa Abdulmajed, Chandigarh / IN

Purpose:

To compare the efficacy of tagging and late gadolinium enhancement in assessing myocardial viability, keeping PET CT as a gold standard.

Methods and materials:

We conducted a prospective analytical study comprised of 28 adult patients with perfusion/metabolism matched or mismatched defects in PET CT. These patients were taken for cardiac MR evaluation, mainly assessing tagging and late gadolinium enhancement for motion and scar respectively. Tagging was assessed using wall grid motion and grid crunching. Scoring was from 1 to 5 in increasing order of wall motion abnormality. Late gadolinium enhancement was graded from 0 to 4, ranging from no enhancement to complete transmural enhancement.

Results:

Out of 448 myocardial segments, 6% (n=27) of the segments were considered non-viable with the matched defect, 56.5% (n=253) were normal, and 37.5% (n=168) were hibernating according to PET CT. 51.1 % (n= 86) of the hibernating segments were akinetic and 48% (n=82) were hypokinetic with the sensitivity of 66.03% (P < 0.001). However, 88.8% (n=24) of the non-viable segments showed severe akinesia with specificity and PPV of tagging of 88.89% and 98.93%, respectively (P<0.001). There was a good concordance between regional wall motion abnormalities detected using tagging and the percentage of transmural enhancement detected using LGE. LGE showed good sensitivity, 91.7%, as compared to PET CT in identifying hibernating myocardium. However, specificity was low at 44.4%.

Conclusion:

Tagging has a good correlation with the late gadolinium enhancement, and as a standalone, MRI parameter shows increased specificity and positive predictive value in identifying non-viable myocardium compared with PET/CT.

Limitations:

A small sample size. Stress examination was not done.

Ethics committee approval

Approved by an institutional ethics committee.

Funding:

No funding was received for this work.

7
RPS 203 - Myocardial perfusion recovery after steroid therapy predicts cardiac events in cardiac sarcoidosis

RPS 203 - Myocardial perfusion recovery after steroid therapy predicts cardiac events in cardiac sarcoidosis

05:31K. Koyanagawa, Sapporo / JP

Purpose:

Whether immunosuppression therapy improves myocardial perfusion in patients with cardiac sarcoidosis (CS) and the association between myocardial perfusion recovery and prognosis are unknown. This study aimed to clarify myocardial perfusion recovery after steroid therapy and its prognostic value for major adverse cardiac events (MACE) in CS patients.

Methods and materials:

38 consecutive patients with steroid-naive CS (median age, 63 IQR 51–68 years; 10 men) underwent electrocardiography (ECG)-gated 99mTc-MIBI SPECT pre- and post-steroid therapy. Patients were classified based on summed rest score (SRS) of pre-steroid therapy and ΔSRS values (SRS post – SRS pre) as follows: improvement (SRS pre > 0 and ΔSRS < 0), non-improvement (SRSpre > 0 and ΔSRS ≥ 0), preservation (SRSpre = 0 and ΔSRS = 0), and progression (SRSpre = 0 and ΔSRS > 0) groups. In addition, we defined the improvement and preservation groups as the recovery group, whereas the non-improvement and progression groups were the non-recovery group.

Results:

From the results of SPECT, 23, 10, 3, and 2 patients were classified into the improvement, non-improvement, preserved, and progression group, respectively. Therefore, 26 patients were assigned to the recovery group and 12 patients to the non-recovery group. MACE occurred in 8 patients after 2.88 years of follow-up. The Kaplan-Meier curves revealed a significantly higher rate of MACE in the non-recovery group (17.4%/y vs. 2.9%/y, P = 0.007).

Conclusion:

Myocardial perfusion was recovered by steroid therapy in 23 (61%) and preserved in 3 (8%) CS patients. Myocardial perfusion recovery after steroid therapy was significantly associated with a low incidence of MACE.

Limitations:

A single-centre study with a small number of patients and events.

Ethics committee approval

Approved by the Ethics Committee of Hokkaido University Hospital.

Funding:

No funding was received for this work.

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