Non-contrast myocardial perfusion in rest and exercise stress using systolic flow-sensitive alternating inversion recovery

Objective To evaluate systolic flow-sensitive alternating inversion recovery (FAIR) during rest and exercise stress using 2RR (two cardiac cycles) or 1RR intervals between inversion pulse and imaging. Materials and methods 1RR and 2RR FAIR was implemented on a 3T scanner. Ten healthy subjects were scanned during rest and stress. Stress was performed using an in-bore ergometer. Heart rate, mean myocardial blood flow (MBF) and temporal signal-to-noise ratio (TSNR) were compared using paired t tests. Results Mean heart rate during stress was higher than rest for 1RR FAIR (85.8 ± 13.7 bpm vs 63.3 ± 11.1 bpm; p < 0.01) and 2RR FAIR (83.8 ± 14.2 bpm vs 63.1 ± 10.6 bpm; p < 0.01). Mean stress MBF was higher than rest for 1RR FAIR (2.97 ± 0.76 ml/g/min vs 1.43 ± 0.6 ml/g/min; p < 0.01) and 2RR FAIR (2.8 ± 0.96 ml/g/min vs 1.22 ± 0.59 ml/g/min; p < 0.01). Resting mean MBF was higher for 1RR FAIR than 2RR FAIR (p < 0.05), but not during stress. TSNR was lower for stress compared to rest for 1RR FAIR (4.52 ± 2.54 vs 10.12 ± 3.69; p < 0.01) and 2RR FAIR (7.36 ± 3.78 vs 12.41 ± 5.12; p < 0.01). 2RR FAIR TSNR was higher than 1RR FAIR for rest (p < 0.05) and stress (p < 0.001). Discussion We have demonstrated feasibility of systolic FAIR in rest and exercise stress. 2RR delay systolic FAIR enables non-contrast perfusion assessment during stress with relatively high TSNR.

Single Snapshot Imaging of Optical Properties (SSOP) for Perfusion Assessment during Gastric Conduit Creation for Esophagectomy: An Experimental Study on Pigs

Anastomotic leakage (AL) is a serious complication occurring after esophagectomy. The current knowledge suggests that inadequate intraoperative perfusion in the anastomotic site contributes to an increase in the AL rate. Presently, clinical estimation undertaken by surgeons is not accurate and new technology is necessary to improve the intraoperative assessment of tissue oxygenation. In the present study, we demonstrate the application of a novel optical technology, namely Single Snapshot imaging of Optical Properties (SSOP), used to quantify StO2% in an open surgery experimental gastric conduit (GC) model. After the creation of a gastric conduit, local StO2% was measured with a preclinical SSOP system for 60 min in the antrum (ROI-A), corpus (ROI-C), and fundus (ROI-F). The removed region (ROI-R) acted as ischemic control. ROI-R had statistically significant lower StO2% when compared to all other ROIs at T15, T30, T45, and T60 (p < 0.0001). Local capillary lactates (LCLs) and StO2% correlation was statistically significant (R = −0.8439, 95% CI −0.9367 to −0.6407, p < 0.0001). Finally, SSOP could discriminate resected from perfused regions and ROI-A from ROI-F (the future anastomotic site). In conclusion, SSOP could well be a suitable technology to assess intraoperative perfusion of GC, providing consistent StO2% quantification and ROIs discrimination.

Non-Contrast Myocardial Perfusion in Rest and Exercise Stress Using Systolic Flow-Sensitive Alternating Inversion Recovery

Objective: To evaluate systolic flow-sensitive alternating inversion recovery (FAIR) during rest and exercise stress using 2RR (two cardiac cycles) or 1RR intervals between inversion pulse and imaging. Materials and Methods: 1RR and 2RR FAIR was implemented on a 3T scanner. Ten healthy subjects were scanned during rest and stress. Stress was performed using an in-bore ergometer. Heart rate, mean myocardial blood flow (MBF) and temporal signal-to-noise ratio (TSNR) were compared using paired t-tests. Results: Mean heart rate during stress was higher than rest for 1RR FAIR (85.8±13.7bpm vs 63.3±11.1bpm; p<0.01) and 2RR FAIR (83.8±14.2bpm vs 63.1±10.6bpm; p<0.01). Mean stress MBF was higher than rest for 1RR FAIR (2.97±0.76ml/g/min vs 1.43±0.6 ml/g/min; p<0.01) and 2RR FAIR (2.8±0.96 ml/g/min vs 1.22±0.59 ml/g/min; p<0.01). Resting mean MBF was higher for 1RR FAIR than 2RR FAIR (p<0.05), but not during stress. TSNR was lower for stress compared to rest for 1RR FAIR (4.52±2.54 vs 10.12±3.69; p<0.01) and 2RR FAIR (7.36±3.78 vs 12.41±5.12; p<0.01). 2RR FAIR TSNR was higher than 1RR FAIR for rest (p<0.05) and stress (p<0.001). Discussion: We have demonstrated feasibility of systolic FAIR in rest and exercise stress. 2RR delay systolic FAIR enables non-contrast perfusion assessment during stress with relatively high TSNR.

663 QUANTITATIVE PERFUSION ASSESSMENT TO PREDICT ANASTOMOTIC LEAK AFTER ESOPHAGECTOMY

Impaired gastric conduit perfusion is a risk factor for anastomotic leak after esophagectomy. Most studies evaluating conduit perfusion have been qualitative with limited impact on post-operative care. The aim of this study is to evaluate the feasibility of intraoperative quantitative assessment of gastric conduit perfusion with indocyanine green (ICG) fluorescence angiography as a predictor for cervical esophagogastric anastomotic (CEGA) leak after esophagectomy. Methods ICG fluorescence angiography using the SPY elite® (Stryker, MI, USA) system was performed in patients who had undergone a transhiatal or McKeown esophagectomy CEGA from July 2015 through December 2020. Fluorescence angiography assessed Ingress (dye uptake) and Egress (dye exit). Ingress Index, Ingress Time, Egress Index, and Egress Time at two anatomic landmarks (tip of the conduit, and 5 cm from tip) were calculated from the measured curve of fluorescence (Figure). The collected data between the leak (L) group and the no-leak (NL) group were compared by both univariate and multivariable analyses to analyze risk factors potentially associated with CEGA leak. Results 304 patients were evaluated. There was no significant difference in patients' demographic and post-operative complications between the groups (L n = 73; NL n = 231), except for anastomotic stricture (42.5 vs 9.1%, p &lt; 0.01). 5 cm and Tip Ingress Index were significantly lower in L (35.0 vs 45.1% and 17.4 vs 25.7%, p &lt; 0.01). 5 cm Ingress Time was significantly higher in L (70.6 vs 56.8 sec, p &lt; 0.01). On multivariable analysis, these variables retained statistical significance, suggesting that these three variables can be used to predict future leak. Conclusion This study revealed that gastric conduit perfusion correlates with the incidence of CEGA leak. Intraoperative measurement of gastric conduit perfusion may be predictive for CEGA leak following esophagectomy. These variables can be easily collected intraoperatively with the SPY study and used to make clinical decisions which may avert CEGA leak.

Qualitative Perfusion Assessment of Myocardial Viability Study in Patients Who Cannot Stop Long-acting Nitrate: Serial Case Reports

The information of myocardial viability status is important to decide the management of CAD. Myocardial viability study (VS) with short-acting nitrate (SAN)-added is recommended to perform inpatient with CAD before revascularization therapy. This study aims to determine whether there are differences in the perfusion results of myocardial viability studies with Long-acting nitrate (LAN) and those with added SAN. Three patients with CAD were referred to our department for myocardial VS to determine the treatment choice. Long-acting nitrate (LAN) was consumed regularly every day and not allowed to be stopped due to the symptomatic chest pain. Patients underwent two myocardial perfusion VS, the first study with continuing the daily routine LAN only and the second one with SAN-added to the daily routine LAN. VS was analyzed qualitatively. The result of this study, no significant perfusion difference between LAN treatment only and SAN-added studies, it is possible the LAN regular dose alone is sufficient to create a vasodilating effect on the arteries without the need for addition of SAN. Conclusion, patients who take LAN routinely, VS might be performed without the need to take additional vasodilator prior to radiopharmaceutical injection.Keywords: coronary artery disease; myocardial perfusion imaging; revascularization therapy; viability study