It may be concluded that in cases where MDCT angiography is utilized with inadequate contrast opacification of the central vessels or suspicion for pseudostenosis artifacts, thorough examination of the vascular tree with diagnostic fistulography would be indicated [84]. Additionally, prior review articles support the usage of MDCT for detection of central stenoses [104]. CTV Extremity Area of Interest With IV Contrast The KDOQI 2019 guidelines state that CTV provides the advantage of offering a noninvasive imaging option that allows for concomitant assessment of the four extremities, noting that the relative timing of the IV contrast bolus and the corresponding image acquisition may be challenging [5]. However, there is no identified literature to support the widespread use of CTV extremity with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast In a meta-analysis by Li et al [11] it was noted that the number of included studies of noncontrast enhanced MRA was not sufficient to support a reliable subgroup analysis. Contrasting to conventional MRA techniques such as time-of-flight and phase-contrast, which depend on phase shift effects or velocity-dependent inflow, the use of gadolinium-enhanced MRA does not rely upon the movement of blood. Unfortunately, in this meta-analysis, the effect could not be explored. Li et al [11] cited that another limitation in MRA lies in the differences in field-of- view between CE-MRA and noncontrast enhanced MRA. The field-of-view of CE-MRA is cited as similar to that of CTA, which includes the complete fistula circuit, namely the inflow artery, arterial anastomosis, draining vein, and central venous outflow to the SVC. However, the field-of-view in noncontrast-enhanced MRA has been reported to exclude imaging of the central venous outflow [11].
Dialysis Fistula Malfunction. It may be concluded that in cases where MDCT angiography is utilized with inadequate contrast opacification of the central vessels or suspicion for pseudostenosis artifacts, thorough examination of the vascular tree with diagnostic fistulography would be indicated [84]. Additionally, prior review articles support the usage of MDCT for detection of central stenoses [104]. CTV Extremity Area of Interest With IV Contrast The KDOQI 2019 guidelines state that CTV provides the advantage of offering a noninvasive imaging option that allows for concomitant assessment of the four extremities, noting that the relative timing of the IV contrast bolus and the corresponding image acquisition may be challenging [5]. However, there is no identified literature to support the widespread use of CTV extremity with IV contrast in evaluation of suspected central stenosis or occlusion suggested by swelling of the extremity ipsilateral to the hemodialysis access. MRA Extremity Area of Interest Without and With IV Contrast In a meta-analysis by Li et al [11] it was noted that the number of included studies of noncontrast enhanced MRA was not sufficient to support a reliable subgroup analysis. Contrasting to conventional MRA techniques such as time-of-flight and phase-contrast, which depend on phase shift effects or velocity-dependent inflow, the use of gadolinium-enhanced MRA does not rely upon the movement of blood. Unfortunately, in this meta-analysis, the effect could not be explored. Li et al [11] cited that another limitation in MRA lies in the differences in field-of- view between CE-MRA and noncontrast enhanced MRA. The field-of-view of CE-MRA is cited as similar to that of CTA, which includes the complete fistula circuit, namely the inflow artery, arterial anastomosis, draining vein, and central venous outflow to the SVC. However, the field-of-view in noncontrast-enhanced MRA has been reported to exclude imaging of the central venous outflow [11].