Diagnostic angioscintigraphic evaluation of malignant hepatic tumors before catheter embolization: determination of shunt, flow distribution, and reflux

Risk factors for the development of pulmonary oil embolism after transcatheter arterial chemoembolization of hepatic tumors

Pulmonary oil embolism (POE) is a rare fatal complication after transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization (TACE). As risk factors have not been clearly delineated, the aim of the present study was to identify the risk factors for development of POE after TACE. A retrospective analysis was carried out on patients with unresectable hepatocellular carcinoma who received TAE or TACE at the Tri-Service General Hospital (Taiwan) between January 2005 and December 2008. The diagnosis of TAE-induced or TACE-induced POE was based on development of respiratory signs and symptoms relatively soon after the procedure, as well as based on characteristic radiographic findings. Of the 219 enrolled patients in this study, 20 were diagnosed with POE after TAE or TACE. On univariate logistic regression analysis, patients developing POE were found to be older (67.95±15.95 vs. 61.44±12.59 years, P=0.033), with a lower serum albumin level (3.25±0.58 vs. 3.62±0.57 g/dl, P=0.009), a higher grade of liver cirrhosis as classified on the basis of Child's criteria (P<0.006), a larger tumor size (8.55±4.52 vs. 4.78±3.97 cm in diameter, P<0.001), a higher lipioidol dose (22.35±11.01 vs. 13.69±7.66 ml, P=0.003), and a higher doxorubicin dose (50.27±7.05 vs. 40.75±13.61 mg, P<0.001). Following multivariate logistic regression analysis, only lipiodol dose was found to be a significant risk factor for POE (odds ratio=1.133, 95% confidence interval: 1.004, 1.279; P=0.044). The receiver operator characteristic curve cutoff point for lipiodol dose level was 14.5 ml, with a sensitivity of 80% and a specificity of 66.3%. In conclusion, the lipiodol dose could be considered as a predictive factor for POE after TAE or TACE in hepatic malignant tumor patients. On the basis of this retrospective study, the safe lipiodol dose to minimize the risk for POE is 14.5 ml or lower; however, larger, prospective studies are needed to determine the optimally safe and yet efficacious dose.

Acute respiratory distress syndrome after transcatheter arterial chemoembolization of hepatocellular carcinomas

BACKGROUND

Acute respiratory distress syndrome (ARDS) associated with pulmonary lipiodol embolism is a rare complication of transcatheter arterial chemoembolization (TACE). We performed a survey of ARDS associated with pulmonary lipiodol embolism after TACE.

METHODS

A retrospective analysis of the cases of all patients with hepatic tumors who received transcatheter arterial embolization or TACE between January 2006 and December 2006 was performed. The diagnosis of pulmonary lipiodol embolism was confirmed by chest computed tomography (CT).

RESULTS

The diagnosis of ARDS associated with pulmonary lipiodol embolism was confirmed in 4 patients. All had large (> or =5 cm) and hypervascular tumors. There was no evidence of hepatocellular carcinoma arteriovenous shunting in any of our patients as determined by angiography and multidetector CT. The volumes of lipiodol infused in the 4 patients were 50, 20, 30, and 20 mL. Only 2 patients received injections of carcinostatic agents. The onset of respiratory symptoms occurred between 1 hour and 4 days after TACE. Respiratory symptoms consisted of dyspnea and tachypnea. Chest CT scans revealed linear high-density shadows, suggestive of lipiodol retention in both lungs of all patients.

CONCLUSION

Pulmonary lipiodol embolism after TACE can occur within a short time frame. Whether or not there is intrahepatic arteriovenous shunting detected by multidetector CT and angiography, clinicians should avoid high doses of iodized oil and carcinostatic agents. We suggest that CT should be used for the diagnosis of pulmonary lipiodol embolism.

Radionuclides delivery systems for nuclear imaging and radiotherapy of cancer

The recent developments of nuclear medicine in oncology have involved numerous investigations of novel specific tumor-targeting radiopharmaceuticals as a major area of interest for both cancer imaging and therapy. The current progress in pharmaceutical nanotechnology field has been exploited in the design of tumor-targeting nanoscale and microscale carriers being able to deliver radionuclides in a selective manner to improve the outcome of cancer diagnosis and treatment. These carriers include chiefly, among others, liposomes, microparticles, nanoparticles, micelles, dendrimers and hydrogels. Furthermore, combining the more recent nuclear imaging multimodalities which provide high sensitivity and anatomical resolution such as PET/CT (positron emission tomography/computed tomography) and SPECT/CT (combined single photon emission computed tomography/computed tomography system) with the use of these specific tumor-targeting carriers constitutes a promising rally which will, hopefully in the near future, allow for earlier tumor detection, better treatment planning and more powerful therapy. In this review, we highlight the use, limitations, advantages and possible improvements of different nano- and microcarriers as potential vehicles for radionuclides delivery in cancer nuclear imaging and radiotherapy.

Angiographic considerations in patients undergoing liver-directed therapy

The rapid evolution and increasing complexity of liver-directed therapies has forced the medical community to further advance its understanding of hepatic arterial anatomy. The anatomy of the mesenteric system, and particularly the hepatic arterial bed, has been demonstrated to have a high degree of variation. This is important when considering presurgical planning, catheterization, and transarterial hepatic therapies. Although anatomic variants have been well described, the characterization and understanding of regional hepatic perfusion is also required to optimize endovascular therapy and intervention. Although this is true for patients undergoing bland embolization or chemoembolization, drug delivery, and hepatic infusional pump therapy, it is particularly true for intraarterial brachytherapy. The purpose of this review is to provide historical perspective in angiographic aspects of liver-directed therapy, as well as a discussion of normal vascular anatomy, commonly encountered variants, and factors involved in changes to regional perfusion in the presence of liver tumors. Methods of optimizing the safety and efficacy of liver-directed therapies with use of percutaneous techniques will be discussed. This review is based on the experience gained in treating more than 500 patients with transarterial liver-directed therapies. Although the principles described in this article apply to all liver-directed therapies such as chemoembolization and administration of drug-coated microspheres, they apply particularly to intraarterial brachytherapy.

Intratumoral arteriovenous shunting in malignant gliomas

OBJECTIVE

Intratumoral arteriovenous shunting in glioblastomas has been suspected but neither proven nor quantified.

METHODS

Using a previously described technique of selective intra-arterial intratumoral injection of 99mTc-labeled microparticles (macroaggregated albumin), we measured the amount of radioactivity, by cerebral and pulmonary scintigraphy, in seven patients with malignant gliomas (six with glioblastomas and one with an anaplastic oligodendroglioma). The pulmonary shunt index was calculated as a percentage from the pulmonary/pulmonary plus cerebral radioactivity ratio.

RESULTS

The results revealed a mean pulmonary shunt index of 67% (range, 47-89%), indicating that most of the microparticles injected into the tumor via the arterial route bypassed the tumor and reached the lungs. The measured arteriovenous shunting was greater when the injection was performed in an artery exclusively perfusing the tumor.

CONCLUSION

Important intratumoral arteriovenous shunting exists in glioblastomas. The potential consequences of this finding for intra-arterial treatment strategies are discussed.