Quantitative Evaluation of Peripheral Arterial Blood Flow Using Peri-Interventional Fluoroscopic Parameters: An In Vivo Study Evaluating Feasibility and Clinical Utility

Abstract

Purpose. The purpose of this study was to evaluate various objective, quantitative, time-resolved fluoroscopic imaging parameters for use in the peri-interventional evaluation of stenotic peripheral arterial disease lesions. Material and Methods. Ten patients (median age, 64; age range, 52 to 79; 8 males, 2 females) with high-grade stenoses of either the superficial femoral or popliteal arteries who underwent endovascular treatment were included. During each intervention, two series of intraprocedural fluoroscopic images were collected, one preintervention and one postintervention. For each imaging series, four regions of interest (ROIs) were defined within the vessel lumen, with two ROIs being proximal (ROIs 1 and 2) and two being distal (ROIs 3 and 4) to the stenosis. The time-density curve (TDC) at each ROI was measured, and the resulting area under the curve (AUC), full width at half maximum (FWHM), and time-to-peak (TTP) were then calculated. Results. The analysis of the TDC-derived parameters demonstrated significant differences between pre- and postinterventional flow rates in the ROI placed most distal to the stenosis, ROI 4. The AUC at ROI 4 (reported as a relative percentage of the AUC measured at ROI 1 proximal to the lesion) demonstrated a significant increase in the total flow (mean 67.84% vs. 128.68%, p=0.003). A significant reduction in FWHM at ROI 4 (mean 2.93 s vs. 1.87 s, p=0.015) was observed. A significant reduction in TTP at ROI 4 (2.43 s to 1.45 s, p=0.009) was also observed. A positive change in at least 1 of the 3 calculated parameters was seen in all patients after a successful intervention, with 7 of 10 patients showing improvement in all 3 parameters, 2 of 10 showing improvement in 2 parameters, and 1 patient showing improvement in 1 parameter. Conclusion. AUC, FWHM, and TTP are objective, reproducible, quantifiable tools for the peri-interventional fluoroscopic evaluation of vessel stenoses. When compared to the standard subjective interpretation of fluoroscopic imagery, AUC, FWHM, and TTP offer interventionalists the advantage of having an objective, complementary method of evaluating the success of a procedure, potentially allowing for more precisely targeted and quantitatively determined treatment goals and improved patient outcomes. This retrospective study was approved by the local ethics committee under the Number 372/2018BO2. The trial was registered at the German clinical trials register under the number DRKS00017813.

A Quantitative Digital Subtraction Angiography Technique for Characterizing Reduction in Hepatic Arterial Blood Flow During Transarterial Embolization

“…The relative change from baseline is larger in qDSA (9.0% reduction in blood velocity per mL of embolic particles delivered) than in ccDSA (1.5% increase in TTP per mL of embolic particles delivered) scans. Previous studies have shown the utility of quantitative fluoroscopy, although those techniques suffer from many of the same limitations as ccDSA [22]. qDSA may feasibly be performed using fluoroscopy, as long as there is sufficient signal in the image to identify peaks in the TAC and there is sufficient temporal resolution to sample the signal.…”

Diagnostic Performance of a Lower‐dose Contrast‐Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3 T Using Multisegmental Time‐Resolved Maximum Intensity Projections

“…Digital subtraction angiography (DSA) is widely regarded as the diagnostic reference standard primarily because dynamic flow information is reliably obtained 3 …”

“…1,2 Digital subtraction angiography (DSA) is widely regarded as the diagnostic reference standard primarily because dynamic flow information is reliably obtained. 3 However, its invasiveness and cost, as well as its requirement for ionizing radiation, have led to the development of MR-angiography (MRA) as an alternative, either as a multistation contrast-enhanced (ce) MRA or as a timeresolved (TR) MRA. MRA has high diagnostic accuracy and is often considered as the imaging modality of choice.…”

Editorial for “Diagnostic Performance of a Lower‐Dose Contrast Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3 T Using Multi‐Segmental Time Resolved Maximum Intensity Projections”

“…Magnetic resonance imaging (MRI) angiography (MRA) appears as an appealing alternative, either as an MRI with multi‐station contrast enhancement (CE) or as time resolution (TR) MRA. Indeed, MRA has high diagnostic accuracy and has been recently proposed as the imaging modality of choice 1–6 …”

“…Indeed, MRA has high diagnostic accuracy and has been recently proposed as the imaging modality of choice. [1][2][3][4][5][6] In this issue of the journal, the authors used DSA to evaluate the diagnostic accuracy of time-resolved 4D MRA with interleaved stochastic trajectories (TWIST-MRA) by using maximum intensity projections (MIPs) of dynamic images acquired with reduced doses of contrast agent. Analyzing 14 patients with a total of 256 artery segments, a high diagnostic performance was achieved for detecting >50% stenosis with a sensitivity and specificity of 92.9% and 98.5%, respectively, and detecting artery occlusion with a sensitivity and specificity of 93.1% and 99.1%, respectively.…”