Nisha I. Sainani

To assess the incidence and sequelae of portal and hepatic venous thrombosis after percutaneous cryoablation of hepatic tumors. From November 1998 through December 2010, 223 hepatic tumors were cryoablated during 170 ablation procedures in 135 patients. 24-h post-procedure MR images were reviewed retrospectively by two abdominal radiologists in consensus to identify tumor ablations that developed one or more new portal or hepatic venous thromboses in or outside the ablation zone. On follow-up MRI and CT examinations the outcomes of thromboses were classified as resolved, partially recanalized, persistent, or propagated. Venous thrombosis developed in association with 54 (24%) of 223 tumor ablations treated during 53 (31%) ablation procedures in 39 (28.8%) patients (15 women, 24 men; age range 40–82 years, mean 59 years). Of these 54 thromboses, 49 (91%) were located in portal vein branches, four (7%) in both portal and hepatic vein branches, and one (2%) in a hepatic vein branch. Thrombosed veins were outside but abutted the ablation zone in 36 (66.7%), and within it in 18 (33.3%). On follow-up imaging (n = 49), thrombi resolved in 29 (59%), partially recanalized in two (4%), persisted in 18 (37%) and propagated from sub-segmental or segmental branches to the left or right portal branches in five (10%). No thrombus propagated to the main portal vein or inferior vena cava. Portal and hepatic vein branch thromboses are common in small branches following percutaneous cryoablation of hepatic tumors and most resolve spontaneously without sequelae.

The purpose of this study was to evaluate the efficacy of CT-guided percutaneous biopsy of isoattenuating liver lesions using anatomic landmarks (ALs) to guide needle placement and added value of intravenous (IV) contrast. An interventional radiology database was reviewed to identify patients with CT-guided percutaneous biopsy of isoattenuating focal liver lesions using ALs to guide needle placement. The cohort was further divided into two groups: lesions biopsied using ALs only and lesions biopsied using ALs and intravenous contrast (AL+IV). Pathology results or follow-up imaging served as reference standard. Sensitivity and accuracy were calculated, Student’s t test and Fisher’s exact test were used for statistical comparison between the two groups. Between January 2000 and December 2011, CT-guided percutaneous biopsy of 133 isoattenuating focal liver lesions was performed in 133 patients. The AL group included 54 patients (M:F = 29:25) with 54 lesions (size range 7–90 mm, mean 32.1 ± 18.1) and AL+IV group included 79 patients (M:F = 44:35) with 79 lesions (size range 7–100 mm, mean 25.6 ± 15.0). AL group included 23 (43%) benign and 31 (57%) malignant lesions; AL+IV group included 31 (39%) benign and 48 (61%) malignant lesions. Sensitivity and accuracy for CT-guided biopsy of focal isoattenuating liver lesions were, overall 94% and 96%, AL group 97% and 98% and AL+IV group 92% and 94%, with no statistical significant difference between the AL and AL+IV groups (P = 0.88–1.00). Accurate planning and utilizing of internal reference ALs is successful in yielding a diagnostic sample for CT-guided percutaneous biopsy of isoattenuating focal liver lesion. The confidence of accurate targeting can be enhanced by administering IV contrast, however, since the visualization provided by IV contrast can be short-lived; use of IV contrast does not obviate the need for precise planning based on ALs.

Image-guided percutaneous biopsy of abdominal masses is among the most commonly performed procedures in interventional radiology. While most abdominal masses are readily amenable to percutaneous biopsy, some may be technically challenging for a number of reasons. Low lesion conspicuity, small size, overlying or intervening structures, motion, such as that due to respiration, are some of the factors that can influence the ability and ultimately the success of an abdominal biopsy. Various techniques or technologies, such as choice of imaging modality, use of intravenous contrast and anatomic landmarks, patient positioning, organ displacement or trans-organ approach, angling CT gantry, triangulation method, real-time guidance with CT fluoroscopy or ultrasound, sedation or breath-hold, pre-procedural image fusion, electromagnetic tracking, and others, when used singularly or in combination, can overcome these challenges to facilitate needle placement in abdominal masses that otherwise would be considered not amenable to percutaneous biopsy. Familiarity and awareness of these techniques allows the interventional radiologist to expand the use of percutaneous biopsy in clinical practice, and help choose the most appropriate technique for a particular patient.

OBJECTIVE. The purpose of this article is to review the spectrum of early and delayed abnormal cross-sectional imaging findings after radiofrequency ablation (RFA) of hepatic tumors. CONCLUSION. Recognition of abnormal post-RFA imaging findings and differentiation of abnormal findings from normal postprocedural changes are important for diagnostic and interventional radiologists. Early identification of residual or recurrent disease and complications can facilitate timely retreatment, management, and follow-up care.

OBJECTIVE. The purpose of this article is to review the spectrum of early and delayed normal cross-sectional imaging findings after percutaneous radiofrequency ablation of hepatic tumors. CONCLUSION. Knowledge of postablation imaging changes is vital not only for the interventionalist who performs the procedure but also for the diagnostician who interprets the postablation imaging. Recognition of normal postprocedural changes and differentiation from abnormal imaging findings prevent overcalling benign changes as abnormal and can thus avoid needless treatment.

The purpose of the study was to compare the quality of stomach and small bowel marking/labeling using 1,350 ml of low-density barium alone (VoLumen) with 900 ml of low-density barium and 450 ml of water for 16-MDCT scans of the abdomen and pelvis and assess cost benefits with the two protocols. In this IRB approved study, 80 consecutive patients scheduled for routine CECT (contrast-enhanced CT) of the abdomen-pelvis were studied. Patients were randomized into two groups and were administered either 1,350 ml of VoLumen (two bottles at 20-min intervals, one half bottle at 50 min and the last half on the table) or 900 ml of VoLumen (two bottles at 20-min intervals and 450 ml water on the table). Portal venous phase scanning (detector collimation = 0.625 mm, speed = 18.75 mm, thickness = 5 mm) was subsequently performed. Images were reconstructed in axial and coronal plane at the CT console. Two blinded readers used a pre-designed template to assess distension and wall characteristics of the stomach and small bowel on a 5-point scale. Median scores with the two protocols were compared using the Wilcoxon rank sum test. The stomach and small bowel labeling was rated fair to optimal in all patients and did not differ significantly in the two protocols. The mean scores for distension of the small bowel and stomach were comparable. Inter-observer agreement for bowel labeling was found to be excellent (k 0.81). With the use of coronal images there was increased reader confidence in tracing the small bowel with both protocols. Acceptance for two bottles of VoLumen and water was greater among patients as compared to three bottles of VoLumen. Use of two bottles of VoLumen and water combination cost less than three bottles of VoLumen. Stomach and small bowel labeling with administration of 900 ml of VoLumen followed by 450 ml of water is cost effective and compares well to 1,350 ml of VoLumen alone.