[Periinterventional cone-beam-CT: application at transarterial chemoembolization of liver tumors]. / Periinterventionelle Cone-Beam-CT: Anwendung bei transarterieller Chemoembolisation von Lebertumoren.

Periinterventional Cone-Beam CT (CBCT) today is a valuable tool in complex radiological interventions. Only little experience exists about CBCT in transarterial chemoembolisations (TACE) of liver tumors. 25 patients underwent periinterventional CBCT. We used a C-arc DSA with 30 × 40 cm flat panel detector. Image data with axial, coronal and 3D-reconstruction were acquired by 217° rotation in 8 seconds. In all 25 cases CBCT had an influence on the TACE regarding the decision which vessels to catheterize, the amount of retention of the embolisation agent or an abort because of insufficient vascularisation. In comparison with DSA alone, CBCT allows a better visualisation of tumour vessels, simplifies selective catheterisation, the decision whether an embolisation is possible and enables a good visualisation of Lipiodol retention. Hence, CBCT is a helpful periinterventional tool but cannot substitute CT and MRI in follow up.

Usefulness of cone-beam volume CT with flat panel detectors in conjunction with catheter angiography for transcatheter arterial embolization.

PURPOSE: To assess the usefulness of cone-beam volume computed tomography (CT) (cone-beam CT) with use of flat panel detectors of the direct conversion type in conjunction with conventional digital subtraction angiography (DSA) in the diagnosis and treatment of patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-nine consecutive patients (52 suspicious lesions) were prospectively examined. All patients underwent intraarterial rotational angiography with a flat panel detector system, and the cone-beam CT scans were reconstructed from the volume data set. The authors evaluated the diagnostic quality of cone-beam CT for the transcatheter arterial chemoembolization (TACE) procedure. RESULTS: The diagnostic quality of conventional DSA plus cone-beam CT with regard to tumor staining was superior to that of DSA alone. Cone-beam CT showed tumor staining in five lesions that were difficult to diagnose with confidence on the basis of the DSA findings alone. The extent of contrast medium perfusion was sufficiently visualized on all cone-beam CT scans at the tip of the catheter positioned in either the segmental or subsegmental hepatic arteries. In 42 of the 52 lesions (81%), cone-beam CT provided additional useful information for therapeutic decision making or TACE compared with DSA. CONCLUSIONS: Intraarterial cone-beam CT with a flat panel detector can provide clinically acceptable image quality in the assessment of HCC, thereby improving the detection of tumor staining due to HCC and the visualization of the extent of contrast medium perfusion.

Tumor imaging in small animals with a combined micro-CT/micro-DSA system using iodinated conventional and blood pool contrast agents.

X-ray based micro-computed tomography (CT) and micro-digital subtraction angiography (DSA) are important non-invasive imaging modalities for following tumorogenesis in small animals. To exploit these imaging capabilities further, the two modalities were combined into a single system to provide both morphological and functional data from the same tumor in a single imaging session. The system is described and examples are given of imaging implanted fibrosarcoma tumors in rats using two types of contrast media: (a) a new generation of blood pool contrast agent containing iodine with a concentration of 130 mg/mL (Fenestratrade mark VC, Alerion Biomedical, San Diego, CA, USA) for micro-CT and (b) a conventional iodinated contrast agent (Isovue(R)-370 mg/mL iodine, trademark of Bracco Diagnostics, Princeton, NJ, USA) for micro-DSA. With the blood pool contrast agent, the 3D vascular architecture is revealed in exquisite detail at 100 microm resolution. Micro-DSA images, in perfect registration with the 3D micro-CT datasets, provide complementary functional information such as mean transit times and relative blood flow through the tumor. This imaging approach could be used to understand tumor angiogenesis better and be the basis for evaluating anti-angiogenic therapies.

Techniques for reducing interventional neuroradiologic skin dose: tube position rotation and supplemental beam filtration.

PURPOSE: To limit the side effects of interventional neuroradiologic radiation, such as epilation, by applying a technique involving tube position rotation and by adding a supplemental inexpensive primary beam filter; and to show the dose effect of modifying technical factors. METHODS: Combined skin dose from fluoroscopy and digital subtraction angiography was measured with an array of 16 thermoluminescent dosimeters during interventional neuroradiologic procedures in 12 control subjects, in 18 patients whose procedures included addition of an inexpensive primary beam filter (0.5 mm aluminum/0.076 mm copper), and in 10 patients in whom the tube position was rotated, additional primary beam filtration was used, and close attention was paid to technique. RESULTS: Maximum thermoluminescent dosimetric measurements obtained with existing machine filtration ranged from 0.31 to 2.70 Gy in the control group (mean, 1.51 +/- 0.88); 0.25 to 2.42 Gy in the group with additional filtration alone (mean 0.96 + 0.64; average dose reduction, 36%); and 0.13 to 1.23 Gy in the group with additional filtration, tube position rotation, and close attention to technique (mean, 0.58 +/- 0.34; average dose reduction, 63%). Differences were statistically significant. CONCLUSIONS: Greater than 50% skin dose reductions were documented during interventional neuroradiologic procedures by combining tube position rotation, supplemental primary beam filtration, and technical modifications.

Small hepatocellular carcinoma. Detection with US, CT, MR imaging, DSA, and Lipiodol-CT.

Twenty-two patients with 37 small (3 cm or less) nodular lesions of hepatocellular carcinoma (HCC) were examined with ultrasonography (US), CT, MR imaging, digital subtraction angiography (DSA), and CT following intraarterial injection of Lipiodol (Lipiodol-CT). All patients subsequently underwent surgery, and the gold standard was provided by intraoperative US. The detection rate was 70% for US, 65% for CT, 62% for MR imaging, 73% for DSA, and 86% for Lipiodol-CT. A significant difference (p < 0.05) was observed between the detection rate of Lipiodol-CT and the detection rates of all the other imaging modalities. The difference was even more manifest (p < 0.02) when only lesions smaller than or equal to 1 cm were considered. It is concluded that Lipiodol-CT is the single most sensitive examination to detect small nodules of HCC. It should therefore be considered a mandatory step in the preoperative evaluation of patients with HCC considered to be surgical candidates after noninvasive imaging studies.

[The magnetic resonance of small hepatocarcinoma. A comparison with echography, computed tomography, digital angiography and computed tomography with lipiodol]. / La risonanza magnetica del piccolo epatocarcinoma. Confronti con ecografia tomografia computerizzata, angiografia digitale e tomografia computerizzata con Lipiodol.

Diagnostic techniques as a whole and periodic ultrasonography (US) in particular frequently allows tumors < 3 cm (small hepatocellular carcinomas) to be detected in patients suffering from liver cirrhosis. Multifocal diseases are a major limitation to surgery. Recently, MR imaging has shown its capabilities in the diagnosis of small hepatocellular carcinomas. In our study the diagnostic value of MR imaging was compared with that of US, of pre- and post-contrast CT, of digital angiography and of CT after lipiodol injection (Lipiodol CT). The morphologic and signal intensity MR features of small hepatocellular carcinomas were investigated. Fifteen cirrhotic patients with 31 nodules of hepatocellular carcinoma < 3 cm were examined. All patients were studied with US, MR imaging, angiography and Lipiodol CT; 12/15 patients underwent CT. Histologic confirmation was obtained in 12 nodules (2 at surgery and 10 by means of percutaneous biopsy); in the extant 19 cases the diagnosis was made by combining US, CT, MR, angiographic and lipiodol-CT findings; in 9 tumors < 1 cm Lipiodol retention one month after angiography was considered as diagnostic. MR imaging detected 21/31 nodules (63%), US 22/31 (66.6%), CT 12/24 (50%), angiography 24/31 (74%), lipiodol CT 29/31 (92.5%). Mc Nemar test showed no difference in sensitivity between MR imaging and CT, MR and angiography, MR and US, lipiodol CT and angiography; however, the differences between the detection rates of MR imaging and Lipiodol CT and CT and lipiodol CT and US were statistically significant (p < 0.05). The difference in sensitivity between the detection rates of lipiodol CT and US was just above the threshold value which is usually considered significant (p = 0.065). One false positive was observed on US and none with MR, CT, angiography and lipiodol CT. On Se T1-weighted images 18 nodules were hyperintense, 2 isointense and 2 hypointense; on proton-density images 14 nodules were hyperintense, 7 isointense and none hypointense. On SE T2-weighted images 18 nodules were hyperintense, 3 isointense and none hypointense. A pseudocapsule was seen in 10/17 nodules (58%), especially on T1-weighted images. Accuracy and limitations of each technique and morphologic and signal intensity MR findings of small hepatocellular carcinoma are discussed. We believe that US is still the best diagnostic technique for the screening of hepatocellular carcinomas in cirrhotic livers.(ABSTRACT TRUNCATED AT 400 WORDS)