Radiolabelled leucocyte scintigraphy versus conventional radiological imaging for the management of late, low-grade vascular prosthesis infections

Abstract

(99m)Tc-HMPAO-WBC SPECT/CT is useful for detecting, localizing and defining the extent of graft infection in patients with late and low-grade late VPI with inconclusive radiological findings. (99m)Tc-HMPAO-WBC SPECT/CT might be used to optimize patient management.

SPECT/CT in infection and inflammation

“…SPECT/ CT, by defining uptake as physiological in the vascular pool or as non-specific abdominal accumulation and providing accurate characterization of the localization and extent of abnormal foci, produced a significant decrease in false-positive findings in 37 % of patients as compared to stand-alone SPECT. This was an important advantage [10] (Fig. 7).…”

“…SPECT/ CT increases both the sensitivity and specificity of 99m Tc-HMPAO WBC by decreasing the rate of false-positive results such as those due to abdominal non-specific accumulation, and by accurately localizing and determining the extent of increased radiotracer uptake. Graft involvement in the infectious process can thus be confirmed or excluded even in the presence of post-surgical distortions and in complex anatomical sites [6,10,91,117]. SPECT/CT provided more accurate data than did planar imaging and SPECT for the diagnosis and localization of VPI using both 67 Ga-citrate and 111 In-oxine-labeled WBCs.…”

“…7). The high specificity of SPECT/CT has been demonstrated even in studies performed during the first month after surgery [10,118]. 99m Tc-HMPAO-WBC SPECT/CT has a major impact on patient management in late, low-grade VPI, partly thanks to its ability to reliably monitor treatment response by distinguishing patients who respond favorably to antibiotics from those who require intensified administration or alternative treatment options [10].…”

“…SPECT/CT studies as an add-on to scintigraphy have been extensively applied to evaluate infectious diseases in various clinical scenarios. These include circumstances that require anatomical landmarks, e.g., when soft-tissue infection has to be differentiated from osseous involvement, in cases in which it is necessary to define all sites of disease and the whole extent of the infectious process in regions with a complex anatomy, as well as when infection is suspected in regions or organs with underlying structural alterations following surgery or implantation of medical devices [5][6][7][8][9][10]. The superiority of SPECT/CT (performed with 111 In-labeled WBCs) over side-by-side reading of SPECT and CT images has been demonstrated in a recent study [11].…”

How useful is 18F-FDG PET/CT in patients with suspected vascular graft infection?

“…In the present study by Bowles et al, it would have been interesting to complete the evaluation of these patients with a radio-labelled leukocyte scan. Recent technological advances such as SPECT/CT have greatly improved the accuracy of leucocyte scintigraphy 14 and this exam should be used more often either as a standalone or as an adjunct to 18F-FDG PET/CT in equivocal cases. The number of patients in this study is relatively small, and validation of these results in a larger study would be of benefits.…”