Opacification of the urinary tract in portal venous spiral CT without delayed scans

Abstract

In portal venous spiral CT there is no visible renal contrast excretion within the usual period of scanning. To opacify collecting systems additional delayed scanning is required. We administered an extra pre-dose of contrast medium before the main portal venous bolus in order to opacify the urinary tract and studied its effects on liver attenuation. In 32 patients examined first by non-contrast spiral CT 20 ml of a non-ionic IV CM were injected. Five minutes later, orientating cuts in the liver and along the urinary tract were obtained. Immediately thereafter, a 120-ml bolus was administered at 3 ml/s for portal venous phase helical CT (60-s delay craniocaudad). The quality of renal excretion was graded visually (excellent, fair, poor, none). Hepatic attenuation measurements were performed at comparable regions of interest. In all patients 20 ml CM opacified the renal pelvis after 5 min. Depiction of the ureters was excellent in 14, fair in 11 and poor or none in 7 cases. There was little effect on mean hepatic attenuation by the 20-ml pre-bolus after 5 min: mean enhancement 2.3 HU (range -0.6 to 7.8 HU). Mean hepatic enhancement after the 120-ml portal venous bolus ranged between 23.6 and 74.1 HU (mean 51.5 HU). When opacification of the urinary tract is necessary, pre-administration of a 20-ml bolus 5 min before portal venous scanning may save an extra delayed spiral. The effects on hepatic enhancement are negligible.

Traumatic Uretero-Pelvic Junction Disruption

“…Alternatively, it has been suggested that the use of a prebolus of 20 ccs of intravenous contrast, given 5 minutes prior to the abdominal CT examination can enhance the renal pelvis in 100% of patients, and in the majority of cases (78%) the ureters as well [ 14 ]. This protocol would provide two obvious advantages.…”

Mehrzeilen-CT-Angiographie der Aorta abdominalis: Bolustracking versus festes Startdelay

“…Die Ursache der Diskrepanz zwischen den unbefriedigenden Ergebnissen für das Bolustracking in der Mehrzeilen-CT der Abdominalgefäße und den Technische Mitteilung überwiegend positiven Berichten zum Bolustracking in der Parenchymdiagnostik der Oberbauchorgane mag zum einem Teil folgende Ursache haben: Die portalvenöse Phase der Leber hat ein relativ flaches Profil mit einem langen Plateau relativ hoher Kontrastierung, während die arterielle Bolusgeometrie von einem kurzen Gipfel mit steilem Anstieg und Abfall charakterisiert ist [26]. Daher spielt die Startlatenz bei der Leber-CT eine geringere Rolle als in der CT-Angiographie.…”