Renal Cyst Pseudoenhancement at Multidetector CT: What Are the Effects of Number of Detectors and Peak Tube Voltage?

Abstract

Purpose:To determine the effect of the number of detectors and peak tube voltage on renal cyst pseudoenhancement in a phantom model. Materials and Methods:This study on computed tomographic (CT) phantoms did not require institutional review board approval. The renal compartments of a CT phantom were filled with iodinated contrast material diluted to attain attenuations of 40, 140, and 240 HU. Saline-filled cylinders simulating cysts of varying diameters (range, 0.7-3.0 cm) were serially suspended in the renal compartments and scanned at 80, 90, 100, 120, and 140 kVp in 16-detector (n ϭ 3) and 64-detector (n ϭ 2) CT scanners. Generalized estimating equations were used to determine predictors of cyst pseudoenhancement (defined as a Ͼ10 HU increase in cyst attenuation when the background renal attenuation increased from 40 to 140 or 240 HU). Results: Conclusion:Lower tube voltage settings may be useful when accurate differentiation between small renal cysts and solid masses is critical, particularly for 64-detector CT scanners.

Evaluation of hyperdense renal lesions incidentally detected on single-phase post-contrast CT using dual-energy CT

“…13,18 Although recent CT technologies have improved, a number of artefacts can lead to pseudoenhancement. 19 In our study with a cut-off value of 20 HU for contrast enhancement, two and nine simple renal cysts demonstrated pseudoenhancement on linearly blended images from the CMP and LNP, respectively.…”

Micro-CT enables microlocalisation and quantification of Her2-targeted gold nanoparticles within tumour regions

“…To produce a difference of 8 HU (0.5 mg Au ml -1 ) with 0.03% id g -1 delivery, 1.7 g of injected gold would be required. However, newer dual-energy and multihead CTs are able to reduce the detection levels further [45,46]. X-ray imaging equipment that would exploit gold's favourable absorption edges would not only improve sensitivity but also reduce patient dose.…”

Precision of the measurement of CT numbers: comparison of dual-energy CT spectral imaging with fast kVp switching and conventional CT with phantoms

“…Clinically, increased attenuation of small simple renal cysts on contrast-enhanced CT is reported as 'pseudoenhancement;' however, enhancement of a renal mass on contrast-enhanced CT is an essential criterion for distinguishing between tumors and benign cysts [5][6][7][8][9][10][11][12][13]. The present results show the effect of the shape of surrounding tissue on the CT number of the lesion of interest.…”

“…The very high linearity observed for all imaging methods and phantoms supports the assumption that focal artifacts do not cause slope inconsistency in conventional imaging; rather, a more diffuse variation of CT numbers exists that can be eliminated by using dualenergy CT imaging. In previously published papers, beam hardening has been frequently mentioned as a cause of pseudoenhancement [5][6][7][8][9][10][11][12][13]. When lower energy photons of the beam are preferentially attenuated by higher density material than water, and images are reconstructed with an algorithm that compensates the excessive attenuation, beam hardening occurs.…”

“…Despite its seemingly physical definition, values are reported to be variable, being dependent on factors such as the model of CT scanner, tube voltage, reconstruction algorithm, and distribution of the examined object [1][2][3][4]. A clinical example of the poor reproducibility of CT number has been reported as pseudoenhancement, such as increased attenuation of small simple renal cysts on contrast-enhanced CT scans [5][6][7][8][9][10][11][12][13].…”