CT-fluoroscopy in chest interventional radiology: sliding scale of imaging parameters based on radiation exposure dose and factors increasing radiation exposure dose

AIM

To verify the usefulness of a sliding scale of imaging parameters to reduce radiation exposure during chest interventional radiology (IR), and to identify factors that increase radiation exposure in order to obtain acceptable computed tomography (CT)-fluoroscopy image quality.

MATERIALS AND METHODS

The institutional review board approved this retrospective study, for which the need for informed consent was waived. Interventional radiologists determined the optimal CT-fluoroscopy imaging parameters using the sliding scale based on the radiation exposure dose. The imaging parameters were changed from those generating low radiation (120 kV/10 mA, 1.2 mGy/s) to others generating higher radiation exposure until acceptable image quality was obtained for each procedure. Validation of the imaging parameter sliding scale was done using regression analysis. Factors that increase radiation exposure were identified using multiple regression analysis.

RESULTS

In 125 patients, 217 procedures were performed, of which 72 procedures (33.2%, 72/217) were performed with imaging parameters of minimum radiation exposure, but increased radiation exposure was necessary in 145 (66.8%, 145/217). Significant correlation was found between the radiation exposure dose and the percentage achievement of acceptable image quality (R(2) = 0.98). Multivariate regression analysis showed that high body weight (p < 0.0001), long device passage (p < 0.0001), and lesions above the aortic arch (p = 0.04) were significant independent factors increasing radiation exposure.

CONCLUSION

Although increased radiation exposure dose might be necessary to obtain acceptable chest CT-fluoroscopy images depending on the patient, lesion, and procedure characteristics, a sliding scale of imaging parameters helps to reduce radiation exposure.

[Hepatic intra-arterial infusion chemotherapy using polymer-coated 2.9 Fr implantable catheter-port system--initial experience]

We developed a new 2.9 Fr implantable catheter-port system (reservoir) to perform arterial infusion chemotherapy in patients with unresectable liver tumors. This study was undertaken to evaluate the feasibility of placing this new reservoir system in patients in whom placement of a 5 Fr-reservoir system would seem to be difficult because of severe stricture, tortuosity or angulation of the hepatic artery. A new reservoir system was successfully implanted in 25 patients during 27 sessions. After a side hole was opened, a 2.9 Fr catheter was inserted in the distal hepatic artery or in the gastroduodenal artery in 24 sessions. The catheter tip was then fixed with coils to prevent catheter dislocation. In the other 3 sessions, a 2.9 Fr catheter was inserted without catheter fixation in the replaced right hepatic artery and a small sized collateral artery towards the liver. Arterial infusion chemotherapy was done without any trouble after 20 sessions. Catheter dislocation was found after 2 sessions in which the catheter tip was not fixed or inadequately fixed. Early arterial occlusion was found after placing a 2.9 Fr catheter in the replaced hepatic artery and the small sized-collateral artery after 4 sessions. In conclusion, although sequellae should be evaluated over a long-term period, implantation of a new 2.9 Fr reservoir system is technically feasible and useful in performing arterial infusion chemotherapy.