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Background: Conventional totally implantable venous access ports (TIVAPs) are not approved for power contrast injections but often remain the only venous access site in oncologic patients. Therefore, these devices can play an important role if patients with a TIVAP are scheduled for a contrast-enhanced computed tomography (ceCT) as vascular access may become more difficult during the course of chemotherapy., Purpose: To evaluate the feasibility and safety of power injections in conventional TIVAPs in the forearm and to analyze the feasibility of bolus triggering during CT scans., Material and Methods: In this retrospective study we analyzed 177 power injections in 141 patients with TIVAPs in the forearm. Between October 2008 and March 2010 all patients underwent power injections (1.5 mL/s, 150 psi) via the TIVAP for ceCT because conventional vascular access via a peripheral vein had failed. Adequate functioning and catheter's tip location after injection were evaluated. Peak injection pressure and attenuation levels of aorta, liver and spleen were analyzed and compared with results of 50 patients who were injected via classical peripheral cannulas (3 mL/s, 300 psi). Feasibility of automatic scan initiation was evaluated. In vitro the port was stressed with 5 mL/s (300 psi)., Results: One TIVAP showed tip dislocation with catheter rupture. Three (2.1%) devices were explanted owing to assumed infection within 4 weeks after the injection. Mean injection pressure was 121.9 +/-24.1 psi. Triggering with automatic scan initiation succeeded in 13/44 (29.6%) scans. Injection via classical cannulas resulted in significantly higher enhancement (p < 0.05). In vitro the port system tolerated flow rates of up to 5 mL/s, injection pressures of up to 338 psi., Conclusion: Power injection is a safe alternative for patients with TIVAPs in the forearm if classic vascular access ultimately fails. Triggering was successful in one-third of the attempts. Image quality in the arterial phase scan may be hampered. In vitro results suggest that the device tolerates even higher flow rates.

This study evaluates the accuracy and reproducibility of an experimental flat-panel-detector-based CT scanner (fp-CT) in comparison with those of a 64-slice multidetector row CT (MDCT) in automated pulmonary nodule volumetry. An anthropomorphic chest phantom with 31 spherical nodules (nodule diameters of 2.94-10.01 mm; volumes of 13.24-524.97 mm(3)) was scanned both with an amorphous silicon-based fp-CT scanner, using various tube current and kilovoltage settings, and with a conventional MDCT scanner. Automated nodule volumetry was performed using dedicated software. CT image data were evaluated twice by two independent radiologists. Intra- and inter-observer variations of volumetric measurements were determined and tested using the Kruskal-Wallis test and analysis of variance (fn-ANOVA). The percentage measurement errors (PME) were calculated and differences tested using Wilcoxon signed ranks and Friedman tests. Intraobserver variation was significantly higher for MDCT than for fp-CT (range: p = 0.043-0.045). The measured nodule volumes were significantly greater on fp-CT than on MDCT scans (p<0.001). The PME was significantly greater in fp-CT than in MDCT scans (PME range, 12.35-13.35% for fp-CT scan protocols and 16.87-19.02% for MDCT scan protocols; p<0.0001). The PME increased significantly with reduction of nodule size, and this increase was significantly higher on MDCT than on fp-CT scans (p = 0.0001). The absolute PME was significantly different for nodules of less than 5 mm in diameter (p = 0.0001-0.0033) than for larger nodules. Flat-panel-detector-based CT has advantages over MDCT in accurately determining the volume of pulmonary nodules below 5 mm in diameter.

To determine the risk of developing contrast induced nephropathy (CIN) in intermediate-risk patients receiving iodixanol, an iso-osmolar, dimeric non-ionic contrast agent, for CT in a clinical setting. Hundred consecutive patients referred for a contrast enhanced CT with a serum creatinine concentration>1.1mg/dl and/or a glomerular filtration rate (GFR)<90ml/min were included. Exclusion criteria were a serum creatinine>2.0mg/dl and a GFR<30ml/min or concurrent nephrotoxic agents. Between 60 and 140ml (mean 97+/-42ml) iodixanol (320mgI/ml) were administered at a flow of 2.5-3ml/s. Hydration with 500ml NaCl i.v. was performed before and after contrast injection. Follow-up was completed in 99 patients (age, 64+/-13 years, 68 men). CIN was defined as increase in serum creatinine concentration +0.5mg/dl or >25% above baseline within 72h after contrast administration. Serum creatinine concentration and GFR were 1.40+/-0.22, 1.29+/-0.29, and 1.26+/-0.29mg/dl and 52.2+/-13.9, 51.3+/-21.1, and 51.5+/-15.1ml/min on days 0, 3, and 7, respectively. Three out of 99 (3%) patients who received 90-110ml iodixanol revealed a CIN on day 3 without persistence on day 7. No specific therapy was needed. One out of 99 patients reported an exanthema on days 3 and 7. With the use of iodixanol in intermediate-risk patients, 3% of the patients develop CIN on day 3 without need for a specific therapy or persistence on day 7.