2D perfusion angiography: an alternative method to evaluate endovascular intervention for acute lower limb ischemia.

BACKGROUND: Despite advances in endovascular techniques to treat acute limb ischemia (ALI), evaluation of clinical outcomes for revascularization remains challenging, especially the accurate quantification of post-endovascular limb perfusion. This study aimed to investigate the accuracy and value of 2D perfusion angiography to evaluate endovascular intervention for ALI. METHODS: A total of 47 patients with ALI were retrospectively analyzed. The transcutaneous oxygen partial pressure (TcPO2) was obtained using laser Doppler blood perfusion monitoring. The ankle-brachial index (ABI) and angiographic images were obtained before and after endovascular intervention. iFlow imaging was used to obtain color-coded images. Regions of interest (ROIs) at the femoral head, knee joint, and ankle joint were selected to obtain the time to peak (TTP). The differences in the TTP between the knee and femoral head regions (TTP difference in the knee area) and between the ankle and knee regions (TTP difference in the ankle area) were observed. The TTP, ABI, and TcPO2 between the complete response (CR), partial response (PR), no response (NR), and amputation (AM) groups were compared. The correlation between TTP changes in the ankle area (ΔTTP) and changes in ABI (ΔABI)/changes in TcPO2 (ΔTcPO2) was analyzed. RESULTS: There was a significant increase in both TcPO2 and ABI compared with the pre-intervention values (27.75 ± 5.32 vs 40.92 ± 4.62, and 0.35 ± 0.16 vs 0.79 ± 0.15, respectively, all p < 0.01). The post-intervention TTP differences in the knee areas (5.12 ± 2.45 s) and ankle areas (6.93 ± 4.37 s) were significantly faster than pre-intervention TTP differences (7.03 ± 2.57 s and 10.66 ± 4.07 s, respectively, all p < 0.05). The post-operative TTP in the ankle area, post-operative TTP difference in the ankle area, and ΔTTP in the AM group were higher than the values in the CR and PR groups. The ΔTTP demonstrated strong correlation with ΔABI (r = -0.722, p < 0.01) and ΔTcPO2 (r = -0.734, p < 0.01). CONCLUSIONS: 2D perfusion angiography with enhanced visual and quantitative analysis exhibits great potential to evaluate the efficacy of endovascular intervention, and provides a quantitative and sensitive tool to evaluate post-endovascular limb perfusion for ALI patients.

2D-perfusion angiography for intra-procedural endovascular treatment response assessment in chronic mesenteric ischemia: a feasibility study.

BACKGROUND: Endovascular revascularization has become the first-line treatment of chronic mesenteric ischemia (CMI). The qualitative visual analysis of digital subtraction angiography (DSA) is dependent on observer experience and prone to interpretation errors. We evaluate the feasibility of 2D-Perfusion Angiography (2D-PA) for objective, quantitative treatment response assessment in CMI. METHODS: 49 revascularizations in 39 patients with imaging based evidence of mesenteric vascular occlusive disease and clinical signs of CMI were included in this retrospective study. To assess perfusion changes by 2D-PA, DSA-series were post-processed using a dedicated, commercially available software. Regions of interest (ROI) were placed in the pre- and post-stenotic artery segment. In aorto-ostial disease, the inflow ROI was positioned at the mesenteric artery orifice. The ratios outflow to inflow ROI for peak density (PD), time to peak and area-under-the-curve (AUC) were computed and compared pre- and post-interventionally. We graded motion artifacts by means of a four-point scale. Feasibility of 2D-PA and changes of flow parameters were evaluated. RESULTS: Motion artifacts due to a mobile vessel location beneath the diaphragm or within the mesenteric root, branch vessel superimposition and inadequate contrast enhancement at the inflow ROI during manually conducted DSA-series via selective catheters owing to steep vessel angulation, necessitated exclusion of 26 measurements from quantitative flow evaluation. The feasibility rate was 47%. In 23 technically feasible assessments, PDoutflow/PDinflow increased by 65% (p < 0.001) and AUCoutflow/AUCinflow increased by 85% (p < 0.001). The time to peak density values in the outflow ROI accelerated only minimally without reaching statistical significance. Age, BMI, target vessel (celiac trunk, SMA or IMA), stenosis location (ostial or truncal), calcification severity, plaque composition or the presence of a complex stenosis did not reach statistical significance in their distribution among the feasible and non-feasible group (p > 0.05). CONCLUSIONS: Compared to other vascular territories and indications, the feasibility of 2D-PA in mesenteric revascularization for CMI was limited. Unfavorable anatomic conditions contributed to a high rate of inconclusive 2D-PA results.

Repeatability, and Intra-Observer and Interobserver Agreement of Two Dimensional Perfusion Angiography in Patients with Chronic Limb Threatening Ischaemia.

OBJECTIVE: Two dimensional (2D) perfusion angiography is a method that provides quantitative foot perfusion information from standard digital subtraction angiography acquisitions. The aim of this study was to test the reliability of this method in patients with chronic limb threatening ischaemia (CLTI) by investigating repeatability, and intra-observer and interobserver agreement. METHODS: Twenty patients with CLTI and a below the knee endovascular revascularisation were included in a prospective clinical study. Prior to treatment two perfusion angiography runs were acquired with a five minute interval without performing an intervention. In these recordings, regions of interest were selected and time density curves and perfusion parameters were determined. To investigate intra-observer agreement one observer performed five measurements on the same acquisition for each patient. To investigate interobserver agreement three observers performed measurements on the same acquisition for each patient. Results were presented in Bland-Altman plots and as the intraclass correlation coefficient per parameter. RESULTS: Two patients were excluded from repeatability analyses because of major motion artefacts. Repeatability analyses of the 18 remaining patients showed excellent correlation for every parameter (> .96). Intra-observer and interobserver agreement for all 20 patients were excellent for all parameters (1.00). CONCLUSION: Repeatability and intra-observer and interobserver agreement of 2D perfusion angiography in patients with CLTI were found to be excellent. It is therefore a reliable tool when used according to the standardised methods described in this study.

Clinical validation of 2D perfusion angiography using Syngo iFlow software during peripheral arterial interventions.

OBJECTIVE: Endovascular surgery is an important treatment modality in peripheral arterial disease. Digital subtraction angiography is the standard post revascularisation diagnostic tool to locate lesions and to evaluate the effect of an intervention. However, interpretation of digital subtraction angiography images is subjective and it is difficult to determine whether revascularisation has been sufficient for clinical improvement. A new technique is 2D perfusion angiography, which creates a 2D colour map and time density curve from the digital subtraction angiography scan for an objective evaluation of the results. However, its clinical relevance is unknown. The aim is to evaluate the association between 2D perfusion angiography parameters and clinical outcome after peripheral arterial interventions. METHODS: In this retrospective study, post revascularisation angiographic data and clinical data were reviewed of patients who underwent treatment of femoral-popliteal or femoral-tibial arteries. The outcome was assessed at three time points using three classification systems for peripheral arterial disease: Fontaine classification, American Medical Association whole person impairment classification (AMA) and average wound, ischemia, foot infection score. Post revascularisation angiographic data consisted of time density curves of the foot and lower leg which were extracted from the Syngo iFlow system (Siemens Healthineers). For each time density curve, five descriptive parameters were calculated: time of arrival, time to peak, mean transit time, wash-in rate and area under the curve. The association between the time density curve parameters and peripheral arterial disease classification systems was assessed using a regression analysis. RESULTS: Between July 2016 and December 2018, 103 patients underwent peripheral endovascular interventions in the hybrid operating room; 39 patients were suitable for analysis, of which 28 patients underwent digital subtraction angiography of the lower leg, 3 patients underwent digital subtraction angiography of the foot and 8 patients underwent digital subtraction angiography of both regions. Limited significant relations were found for time of arrival with Fontainde classification (B = 0.806, p = 0.043) and area under the curve with AMA classification (B = -0.027, p = 0.047). CONCLUSION: In this retrospective study, time density curve parameters (time of arrival and area under the curve), measured in the lower leg, showed a limited significant association with two classification systems for peripheral arterial disease. Future prospective studies to determine the clinical relevance of this 2D perfusion angiography method should focus on standardisation of angiography protocols and comparison of pre- and post-intervention parameters.

Chronic thromboembolic pulmonary hypertension: Evaluation of 2D-perfusion angiography in patients who undergo balloon pulmonary angioplasty.

OBJECTIVE: To evaluate the feasibility of 2D-perfusion angiography (2D-PA) in order to quantify perfusion changes of the lung parenchyma pre- and post-balloon pulmonary angioplasty (BPA). METHODS: Thirty consecutive interventions in 16 patients with 99 treated pulmonary artery segments were included. To quantify changes in pulmonary blood flow using 2D-PA, the acquired digital subtraction angiographies (DSA) pre- and post-BPA were post-processed. A reference ROI in the treated pulmonary artery and a distal target ROI in the lung parenchyma were placed in corresponding areas on DSA pre- and post-BPA. Time to peak (TTP), peak density (PD) and area under the curve (AUC) were assessed. The ratios reference ROI to target ROI (TTPparenchyma/TTPinflow; PDparenchyma/PDinflow; AUCparenchyma/AUCinflow) were calculated. Relative differences of the 2D-PA parameters were correlated to changes in the pulmonary-flow-grade-score. RESULTS: The pulmonary-flow-grade-score improved after BPA (p<0.0001). Likewise, the ratio TTPparenchyma/TTPinflow shortened by 10% (p=0.0002), the PDparenchyma/PDinflow increased by 46% (p<0.0001) and the AUCparenchyma/AUCinflow increased by 36% (p<0.0001). A significant correlation between changes in the pulmonary-flow-grade-score and changes in PDparenchyma/PDinflow (ρ=0.48, p<0.0001) and AUCparenchyma/AUCinflow (ρ=0.31, p=0.0018) was observed. CONCLUSION: Quantification of pulmonary perfusion pre- and post-BPA using 2D-PA is feasible and has the potential to improve monitoring of BPA. KEY POINTS: • Quantification of BPA results by use of 2D-PA is feasible. • 2D-PA allows objective assessment of changes in lung parenchymal perfusion. • 2D-PA has the potential to optimize BPA.

X-ray Angiography Perfusion Analysis for the Balloon Occlusion Test of the Internal Carotid Artery.

BACKGROUND: A perfusion study should be performed during the balloon occlusion test (BOT) to prevent ischemic events after therapeutic carotid occlusion. We evaluated the efficacy of X-ray angiography perfusion analysis during the BOT. METHODS: Twenty-one consecutive patients who underwent the BOT of the internal carotid artery were included. Patients who had a venous phase delay of less than .5 seconds and a mean stump pressure of more than 50 mm Hg without any neurologic symptoms were considered tolerant, and other patients were considered intolerant. A time-density curve was constructed for each hemisphere using X-ray angiography perfusion software (2D-Perfusion). The mean transit time and area under the curve, which correspond to cerebral blood volume, were calculated from the curve. Differences in these parameters between the occluded and nonoccluded hemispheres and the perfusion index were compared between the tolerant and intolerant groups. RESULTS: In the intolerant group, the mean transit time was significantly longer (1.31 ± .72 seconds versus .44 ± .21 seconds, P = .001) and the perfusion index was significantly lower (.72 ± .16 versus .94 ± .08, P = .001) compared with those in the tolerant group. The area under the curve was not different between the groups. CONCLUSIONS: Parameters obtained by X-ray angiography perfusion analysis were significantly different between the tolerant and intolerant groups. The X-ray angiography perfusion analysis could be a safe and effective method for assessing ischemic tolerance before therapeutic carotid occlusion.

Angiosome-directed endovascular intervention and infrapopliteal disease: Intraoperative evaluation of distal hemodynamic changes and foot blood volume of lower extremity.

Objectives: To evaluate foot blood volume and hemodynamics and explore whether quantitative techniques can guide revascularization. Materials and methods: A prospective single-center cohort study included thirty-three patients with infrapopliteal artery occlusion who underwent percutaneous transluminal angioplasty (PTA) between November 2016 and May 2020. The time-to-peak (TTP) from color-coded quantitative digital subtraction angiography (CCQ-DSA) and parenchymal blood volume (PBV) were used to evaluate the blood volume and hemodynamic changes in different regions of the foot before and after the operation. Results: After the intervention procedure, the overall blood volume significantly increased from 25.15 ± 21.1 ml/1,000 ml to 72.33 ± 29.3 ml/1,000 ml (p < 0.001, with an average increase of 47.18 ml/1,000 ml. The overall TTP decrease rate, postoperative blood flow time significantly faster than those preoperatively, from 22.93 ± 7.83 to 14.85 ± 5.9 s (p < 0.001, with an average decrease of 8.08 s). Direct revascularization (DR) resulted in significant blood volume improvement than compared with indirect revascularization (IR) [188% (28, 320) vs.51% (10, 110), p = 0.029]. Patients with DR had a significantly faster blood flow time than those with IR [80% (12, 180) vs. 26% (5, 80), p = 0.032]. The ankle-brachial index (ABI) of the affected extremity also showed an significant change from 0.49 ± 0.3 to 0.63 ± 0.24 (p < 0.001) after the intervention. The relative values of ΔTTP and ΔABI showed a weak correlation (r = -0.330). Conclusions: The quantitative measurement results based on PBV and CCQ-DSA techniques showed that the overall blood volume increased significantly and that the foot distal hemodynamics were significantly improved after endovascular treatment. DR in the ischemic area could r improve foot perfusion.

2D-Perfusion Angiography Using Carbon Dioxide (CO2): A Feasible Tool to Monitor Immediate Treatment Response to Endovascular Therapy of Peripheral Arterial Disease?

PURPOSE: Patients with peripheral arterial disease (PAD) or critical limb ischemia (CLI) require revascularization. Traditionally, endovascular therapy (EVT) is performed with iodinated contrast agent (ICM), which can provoke potential deterioration in renal function. CO2 is a safe negative contrast agent to guide vascular procedures, but interpretation of CO2 angiography is challenging. Changes in blood flow following iodine-aided EVT are assessable with 2D-perfusion angiography (2D-PA). The aim of this study was to evaluate 2D-PA as a tool to monitor blood flow changes during CO2-aided EVT. MATERIAL AND METHODS: 2D-PA was performed before and after ten EVTs (nine stents; one endoprosthesis; 10/2012-02/2020) in nine patients (six men; 65 ± 10y) with Fontaine stage IIb (n = 8) and IV (n = 1). A reference ROI (ROIINFLOW) was placed in the artery before the targeted obstruction and a target ROI (ROIOUTFLOW) distally. Corresponding ROIs were used pre- and post-EVT. Time to peak (TTP), peak density (PD) and area under the curve (AUC) were computed. The reference/target ROI ratios (TTPOUTFLOW/TTPINFLOW; PDOUTFLOW/PDINFLOW; AUCOUTFLOW/AUCINFLOW) were calculated. RESULTS: 2D-PA was technically feasible in all cases. A significant increase of 82% in PDOUTFLOW/PDINFLOW (0.44 ± 0.4 to 0.8 ± 0.63; p = 0.002) and of 132% in AUCOUTFLOW/AUCINFLOW (0.34 ± 0.22 to 0.79 ± 0.59; p = 0.002) was seen. A trend for a decrease in TTPOUTFLOW/TTPINFLOW was observed (- 24%; 5.57 ± 3.66 s-4.25 ± 1.64 s; p = 0.6). CONCLUSION: The presented 2D-PA technique facilitates the assessment of arterial flow in CO2-aided EVTs and has the potential to simplify the assessment of immediate treatment response.

Usefulness of 2D-Perfusion Analysis for the Assessment of Unilateral Cervical Internal Carotid Artery Stenosis.

Objective: We investigated the usefulness of 2D-perfusion analysis for the evaluation of cerebral blood flow in unilateral cervical internal carotid artery stenosis. Methods: We conducted a 2D-perfusion analysis during cerebral angiography and 123I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) for unilateral cervical internal carotid artery stenosis without contralateral stenosis. The relationship between the ratio of the lesion side to the normal side in the parameters obtained by 2D-perfusion and the value calculated by stereotactic extraction estimation (SEE) analysis of SPECT was statistically examined. Results: The ratios of the lesion side to the normal side regarding the peak arrival time (AT; time to peak [TTP]) of the contrast agent and the mean filling time (mean transit time [MTT]) of the contrast agent in 2D-perfusion significantly correlated with the area of Stage II and increase ratio (I.R) ≤30% in the SEE analysis (p = 0.002, 0.003). Conclusion: 2D-perfusion analysis can be used to estimate the extent of impaired cerebrovascular reserve (CVR) area in unilateral internal carotid artery stenosis.

Non-occlusive mesenteric ischemia (NOMI): evaluation of 2D-perfusion angiography (2D-PA) for early treatment response assessment.

PURPOSE: To evaluate the feasibility of 2D-perfusion angiography (2D-PA) for the analysis of intra-procedural treatment response after intra-arterial prostaglandin E1 therapy in patients with non-occlusive mesenteric ischemia (NOMI). METHODS: Overall, 20 procedures in 18 NOMI patients were included in this retrospective case-control study. To evaluate intra-procedural splanchnic circulation changes, post-processing of digital subtraction angiography (DSA) series was performed. Regions of interest (ROIs) were placed in the superior mesenteric artery (SMA; reference), the portal vein (PV; ROIPV), as well as the aorta next to the origin of the SMA (ROIAorta). Peak density (PD), time to peak (TTP), and area under the curve (AUC) were assessed, and parametric ratios 'target ROIPD, TTP, AUC/reference ROI' were computed and compared within treatment and control group. Additionally, a NOMI score was assessed pre- and post-treatment compared to 2D-PA. RESULTS: Vasodilator therapy leads to a significant decrease of the 2D-PA-derived values PDAorta (p = 0.04) and AUCAorta (p = 0.03). These findings correlated with changes of the simplified NOMI score, both for overall (4 to 1, p < 0.0001) and for each category. Prostaglandin application caused a significant increase of the AUCPV (p = 0.04) and TTPPV was accelerated without reaching statistical significance (p = 0.13). When compared to a control group, all 2D-PA values in the NOMI group (pre- and post-intervention) differed significantly (p < 0.05) with longer TTPAorta/PV and lower AUCAorta/PV and PD Aorta/PV. CONCLUSION: 2D-PA offers an objective approach to analyze immediate flow and perfusion changes following vasodilatory therapies of NOMI patients and may be a valuable tool for assessing treatment response.

Chemosaturation Percutaneous Hepatic Perfusion (CS-PHP) with Melphalan: Evaluation of 2D-Perfusion Angiography (2D-PA) for Leakage Detection of the Venous Double-Balloon Catheter.

PURPOSE: To evaluate the feasibility of 2D-perfusion angiography (2D-PA) for detecting leakage of the double-balloon catheter used for chemosaturation percutaneous hepatic perfusion (CS-PHP). MATERIALS AND METHODS: Overall, 112 CS-PHP (09/2015-09/2018) in 52 patients were retrospectively screened for leakage alongside the double-balloon catheter on standard venograms. Finally, 18 procedures with visually detected leakage were included. Fifteen consecutive procedures without leakage served as control. To evaluate 2D-PA for leakage detection, the acquired digital subtraction venograms were post-processed. For each balloon, two different target ROIs were evaluated to assess a possible impact of localization and shape of the ROIs. Time to peak (TTP), peak density (PD), area under the curve (AUC), and ratios of target ROI/reference ROIs (PDtROI/PDREF; AUCtROI/AUCREF; and TTPtROI/TTPREF) were calculated. RESULTS: Leakages were located as follows: 15/18 cranial and 3/18 caudal. At the cranial balloon both ROIs showed a significant decrease in PDtROI/PDREF and AUCtROI/AUCREF (ROI1: p < 0.0001; p < 0.0001; ROI2: p < 0.0001; p < 0.0001) and a significant increase in TTPtROI/TTPREF (ROI1: p = 0.0009; ROI2: p = 0.0003) after double-balloon correction. Following balloon adjustment, the 2D-PA ratios (PD and AUC) of the tested ROIs differed significantly (p < 0.05). The inter-individual comparison of the 2D-PA parameters of the group with leakage before balloon correction and the non-leakage group showed significantly different 2D-PA values for the cranial balloon in both ROIs (p < 0.05). No significant differences were found for the caudal balloon. CONCLUSION: 2D-PA provides a feasible tool for detecting leakages alongside the cranial portion of the double-balloon catheter used in CS-PHP. The shape and position of the ROIs used to assess perfusion and flow have an impact on the measurements.

Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction: quantitative assessment of flow and perfusion changes using 2D-perfusion angiography following shunt revision.

PURPOSE: To analyze the feasibility of 2D-perfusion angiography (2D-PA) to quantify flow and perfusion changes pre- and post-transjugular intrahepatic portosystemic shunt (TIPS) revision. MATERIALS AND METHODS: Fifteen consecutive patients (54 ± 14 years, seven men and eight women) scheduled for TIPS revision were included in this study. To quantify flow and perfusion changes caused by TIPS revision, digital subtraction angiography (DSA) series acquired during the revision were post-processed using a dedicated software. Reference region-of-interest (ROI) in the main portal vein (input function) and target ROIs in the TIPS lumen, the liver parenchyma and in the right atrium were placed in corresponding areas on DSA pre- and post-TIPS revision. 2D-PA evaluation included time to peak (TTP), peak density (PD), and the area under the curve (AUC) assessment. The ratios of reference ROI to target ROIs pre- and post-TIPS revision were calculated (TTPparenchyma/TTPinflow, PDparenchyma/PDinflow, AUCparenchyma/AUCinflow, TTPTIPS/TTPinflow, PDTIPS/PDinflow, AUCTIPS/AUCinflow, TTPatrium/TTPinflow, PDatrium/PDinflow, and AUCatrium/AUCinflow). Pressure measurements pre- and post-TIPS revision were performed and correlated to the 2D-PA parameters. Reproducibility of 2D-PA was assessed by the intra-class correlation coefficient (ICC). RESULTS: The portosystemic pressure gradient was significantly reduced following TIPS revision (17.1 ± 6.3 vs. 8.9 ± 4.3 mmHg; p < 0.0001). PDTIPS/PDinflow (0.22 vs. 0.35; p = 0.0014) and AUCTIPS/AUCinflow (0.24 vs. 0.39; p = 0.0012) increased significantly. Likewise, PDatrium/PDinflow (0.32 vs. 0.78; p = 0.0004) and AUCatrium/AUCinflow (0.3 vs. 0.79; p < 0.0001) increased, whereas PDparenchyma/PDinflow decreased significantly (0.14 vs. 0.1; p = 0.0084). Pressure gradient changes correlated significantly with the increase in PDatrium/PDinflow (r = - 0.77, p = 0.0012) and AUCatrium/AUCinflow (r = - 0.76, p = 0.0018). ICC of the 2D-PA parameters was in the range of 0.88-0.99. CONCLUSION: 2D-PA offers a feasible approach to quantify flow and perfusion changes during TIPS revision. Therefore, 2D-PA may be a valuable amendment to mere pressure measurements.

Quantification of perfusion reduction by using 2D-perfusion angiography following transarterial chemoembolization with drug-eluting beads.

PURPOSE: To analyze the feasibility of 2D-perfusion angiography (2D-PA) for the quantification of perfusion reduction following transarterial chemoembolization with drug-eluting beads (DEB-TACE). METHODS: Overall, 24 DEB-TACE procedures in 19 patients were included. To quantify changes in tumor perfusion following DEB-TACE using 2D-PA, the acquired digital subtraction angiography (DSA) series were post-processed. A reference region-of-interest (ROI) in a main hepatic artery and two, distal target ROIs in embolized tumor tissue and in non-target liver parenchyma were placed in corresponding areas on DSA pre- and post-DEB-TACE. The time to peak (TTP), peak density (PD), and the area under the curve (AUC) were assessed and the ratios reference ROI/target ROIs were calculated. RESULTS: In the embolized tumor, the 2D-PA ratios changed significantly (p < 0.05) after DEB-TACE, whereas no significant change was observed for non-target liver parenchyma (p > 0.05). PDtumor/PDinflow differed significantly to PDparenchyma/PDinflow pre-DEB-TACE (p < 0.0001), likewise AUCtumor/AUCinflow to AUCparenchyma/AUCinflow (p < 0.0001) with higher values in tumor tissue. The post-DEB-TACE ratios of AUC decreased significantly in the tumor tissue compared to the non-target liver parenchyma (p < 0.05). CONCLUSION: 2D-PA offers an objective approach to quantify the immediate perfusion reduction of embolized tumor tissue following DEB-TACE and may therefore be used to monitor peri-interventional stasis and to quantify technical success.

Efficacy of Two-Dimensional Perfusion Angiography for Evaluations after Infrapopliteal Bypass Surgery for Critical Limb Ischemia.

Two-dimensional perfusion angiography (2DPA) is utilized in hybrid operating rooms. 2DPA produces color map images and functional parameters to provide more robust visual and quantitative evaluations than conventional angiography. Its efficacy was suggested in five patients following bypass surgery; unexpected results were obtained in one patient, leading to a decision to perform surgical re-anastomosis. Furthermore, we found that the general anesthesia eliminates body movements that tend to disrupt 2DPA results. 2DPA was more useful during surgical revascularization than conventional angiography and provided more detailed information.

Evaluation of a novel 2D perfusion angiography technique independent of pump injections for assessment of interventional treatment of peripheral vascular disease.

To evaluate a novel 2D-perfusion angiography (2D-PA) technique allowing pro- and retrospective flow analysis based on a proximal reference region of interest (ROI) and distal target ROI in patients treated for peripheral arterial disease. 2D-PA allows quantifying blood flow by post-processing of digital subtraction angiography (DSA). 2D-PA was performed pre and post interventional treatment of peripheral arterial disease (PAD; n = 24; 13 angioplasties, 11 stents) in 21 patients (17 men, 72 ± 9y) with Fontaine stage IIB / III. Time-to-peak (TTP), peak density (PD) and area-under-the-curve (AUC) were calculated. Ratios reference/target ROI (TTPOUTFLOW/TTPINFLOW; PDOUTFLOW/PDINFLOW; AUCOUTFLOW/AUCINFLOW) were calculated and correlated to changes in the ankle-brachial-index (ABI). 2D-PA was technically feasible in all cases. A significant increase in ABI was seen after interventional treatment (+39%; p < 0.0001). ABI increase was accompanied by an increase of 36% of PDOUTFLOW/PDINFLOW (p < 0.0001), a 52% decrease of TTPOUTFLOW/TTPINFLOW (p = 0.0007) and a 69% increase of AUCOUTFLOW/AUCINFLOW (p < 0.0001). The difference of TTP pre- and post-intervention showed a correlation with the difference in ABI (r = -0.53, p = 0.0081). The other measured parameters failed to demonstrate significant correlation with improved ABI. The presented 2D-PA technique allows quantitative assessment of arterial flow before, during and after interventional treatment in PAD.

Feasibility of Real-Time Angiographic Perfusion Imaging in the Treatment of Cerebral Vasospasm.

BACKGROUND: Objective assessment and quantification of the severity of cerebral vasospasm following aneurysmal subarachnoid hemorrhage is not routinely utilized. We investigated the feasibility of angiographic perfusion imaging derived from digital subtraction angiography (DSA) following endovascular vasospasm treatment procedures. METHODOLOGY: Real-time blood flow analysis was performed using parametric color coding on pre- and postintervention DSA. Semiquantitative parenchymal perfusion parameters (arrival time [AT] of contrast, time to peak [TTP] opacification, and mean transit time [MTT] of contrast) were calculated across 3 vascular territories (anterior cerebral artery [ACA], middle cerebral artery [MCA], and lenticulostriate arteries) using standard 2-D angiographic perfusion software. The pre- and postintervention arterial vessel diameters were compared. RESULTS: Twelve endovascular vasospasm treatments in 6 patients were performed. All patients received intra-arterial vasodilator therapy with either nimodipine, milrinone, or both. Following intra-arterial intervention, parenchymal flow analysis showed improvement in TTP and MTT across all vascular territories (p < 0.002) and improvement in AT in the ACA and MCA territories (p < 0.03). Improvement in parenchymal perfusion parameters was associated with improvement in vessel diameters in all territories following treatment (p < 0.05). CONCLUSION: Real-time parenchymal perfusion imaging during endovascular vasospasm treatment procedures is feasible and provides reliable semiquantitative measurement of angiographic treatment response.