Pre-procedural CT Imaging Research Articles

Radiomics Analysis of Preprocedural CT Imaging for Outcome Prediction after Transjugular Intrahepatic Portosystemic Shunt Creation.

To evaluate the role of radiomics in preoperative outcome prediction in cirrhotic patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) using "controlled expansion covered stents". This retrospective institutional review board-approved study included cirrhotic patients undergoing TIPS with controlled expansion covered stent placement. From preoperative CT images, the whole liver was segmented into Volumes of Interest (VOIs) at the unenhanced and portal venous phase. Radiomics features were extracted, collected, and analyzed. Subsequently, receiver operating characteristic (ROC) curves were drawn to assess which features could predict patients' outcomes. The endpoints studied were 6-month overall survival (OS), development of hepatic encephalopathy (HE), grade II or higher HE according to West Haven Criteria, and clinical response, defined as the absence of rebleeding or ascites. A radiomic model for outcome prediction was then designed. A total of 76 consecutive cirrhotic patients undergoing TIPS creation were enrolled. The highest performances in terms of the area under the receiver operating characteristic curve (AUROC) were observed for the "clinical response" and "survival at 6 months" outcome with 0.755 and 0.767, at the unenhanced and portal venous phase, respectively. Specifically, on basal scans, accuracy, specificity, and sensitivity were 66.42%, 63.93%, and 73.75%, respectively. At the portal venous phase, an accuracy of 65.34%, a specificity of 62.38%, and a sensitivity of 74.00% were demonstrated. A pre-interventional machine learning-based CT radiomics algorithm could be useful in predicting survival and clinical response after TIPS creation in cirrhotic patients.

Pre-procedural and intra-procedural computerized tomography: providing a roadmap for successful adrenal venous sampling procedures

Background and purposeAdrenal venous sampling (AVS) is used for the diagnosis of primary hyperaldosteronism. Technical difficulties with right adrenal vein (RAV) catheterization can lead to erroneous results. Our purpose was to delineate the location of the RAV on pre-procedural CT imaging in relation to the location identified during AVS and to report on the impact of successful RAV cannulation with and without the use of intra-procedural CT scanning.MethodsRetrospective case series including patients who underwent AVS from October 2000 to September 2022. Clinical and laboratory values were abstracted from the electronic medical record. Successful cannulation of the RAV was defined as a selectivity index > 3.Results110 patients underwent 124 AVS procedures. Pre-AVS CT imaging was available for 118 AVS procedures. The RAV was identified in 61 (51.7%) CT datasets. Biochemical confirmation of successful RAV cannulation occurred in 98 (79.0%) of 124 AVS procedures. There were 52 (85.2%) procedures in which the RAV was identified on pre-AVS CT and there was biochemical confirmation of successful RAV sampling. Among these 52 procedures, the RAV was localized during AVS at the same anatomic level or within 1 vertebral body level cranial to the level identified on pre-AVS CT in 98.1% of cases. The rate of successful RAV cannulation was higher in patients who underwent intra-procedural CT (93.8% versus 63.9%), P < 0.01.ConclusionsPre-AVS and intra-procedural CT images provide an invaluable roadmap that resulted in a higher rate of accurate identification of the RAV and successful AVS procedures; in particular, search for the RAV orifice during AVS can be limited to 1 vertebral body cranial to the level identified on pre-AVS CT imaging and successful cannulation can be confidently verified with intra-procedural CT.

Identification of coronary plaque rupture or erosion by preprocedural computed tomography angiography in patients with non-st-segment elevation acute coronary syndrome

Abstract Background The frequent pathological cause of acute coronary thrombosis is plaque rupture or erosion. A previous CT angiographic study failed to discriminate OCT-defined intact fibrous cap culprit lesions (IFC lesions) from those with ruptured fibrous cap (RFC group) in patients with acute coronary syndrome (ACS) and chronic coronary syndrome. Objectives This study aimed to evaluate the diagnostic efficacy of preprocedural coronary CT imaging to identify optical coherence tomography (OCT)-defined plaque rupture or erosion at culprit lesions in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Methods Consecutive patients with suspected NSTE-ACS who underwent preprocedural non-contrast CT and CT angiography (CCTA) were studied. Patients with at least one lesion with more than 50% stenosis at the proximal segment on CCTA were subsequently assessed by invasive coronary angiography and OCT. ALL CT and OCT examination were performed within 24 hours from presentation. The diagnosis of intact fibrous cap or ruptured fibrous cap was made by OCT for the angiographically most severely stenosed lesion. Cases of ambiguous OCT diagnosis such as massive thrombosis or calcified nodule precluding the fibrous cap assessment were excluded from the final analysis. Results In the final analysis of 176 patients, OCT identified 87 RFC plaques and 89 IFC plaques for the culprit lesions, respectively. In IFC group, lower prevalence of diabetes mellitus (24.7% vs. 41.4%, P=0.025) and lower peak cardiac marker elevation (CPK, 159 vs. 272 U/L, P&amp;lt;0.001) were observed. On CT, the prevalence of low attenuation plaque, positive remodeling, napkin ring sign, spotty calcification, calcium score (CAC), and culprit vessel pericoronary adipose tissue attenuation (FAI) were all significantly low in IFC group. Multivariate regression analysis to predict IFC at culprit lesions revealed that the absence of low attenuation plaque, the absence of napkin ring sign, zero CAC, and low FAI were independent predictors of IFC. When stratified by the number of these 4 CT factors, the presence of IFC were stratified as 0%, 23.6%, 50%, 77.8%, and 100% (P&amp;lt;0.001), respectively. Adding non-contrast CT factor of zero CAC to the reference model including age, sex, DM, EF, low attenuation plaque, napkin ring sign, and FAI, can increase the incremental discriminatory and reclassification performance for the prediction of IFC (C-statistic 0.828 NRI: 0.37, 95% CI: 0.095–0.646, P=0.008 and IDI: 0.042, 95% CI: 0.012–0.071, P=0.005). Conclusions Preprocedural comprehensive CT imaging including CAC and pericoronary adipose tissue inflammation could identify IFC or RFC culprit lesions defined by OCT. Further studies are needed to confirm our preliminary results and if CT imaging in NSTE-ACS provides prognostic information or specific therapeutic approach such as conservative therapy or non-stenting strategy before invasive angiography. Funding Acknowledgement Type of funding sources: None.

Pre-procedural CT imaging aids neonatal PDA stenting for ductal-dependent pulmonary blood flow with reduction in overall procedural morbidity.

Patent ductus arteriosus stenting for ductal-dependent pulmonary blood flow is a technically challenging neonatal procedure to maintain a stable pulmonary circulation. Pre-procedural computed tomography imaging aids in outlining ductal origin, insertion, size, course and curvature. Computed tomography imaging may add value to procedural outcomes and reduce overall procedural morbidity in neonatal patent ductus arteriosus stenting. We conducted a single centre retrospective chart review of neonates with ductal-dependent pulmonary blood flow who underwent patent ductus arteriosus stenting between January 1, 2014 and June 31, 2020. We compared patients variables between patients who underwent pre-procedural computed tomography imaging to those who did not. A total of 64 patients were referred for patent ductus arteriosus stenting with 33 (52%) obtaining pre-procedural computed tomography imaging. Average age [19 days; range 1-242 days (p = 0.85)] and weight [3.3 kg (range 2.2-6.0 kg; p = 0.19)] was not significantly different between the groups. A diagnosis of pulmonary atresia was made in 42 out of 64 (66%) patients prior to patent ductus arteriosus stenting. The cohort with pre-intervention computed tomography imaging had a significant reduction in the total number of access sites (1.2 versus 1.5; p = 0.03), contrast needed (5.9 versus 8.2 ml/kg; p = 0.008), fluoroscopy (20.7 versus 38.8 minutes; p = 0.02) and procedural time (83.4-128.4 minutes; p = 0.002) for the intervention. There was no significant difference in radiation burden between the groups (p = 0.35). Pre-procedural computed tomography imaging adds value by aiding interventional planning for neonatal patent ductus arteriosus stenting. A statistically significant reduction in the number of access sites, contrast exposure, as well as fluoroscopic and procedural time was noted without significantly increasing the cumulative radiation burden.

Impact of local left atrial wall thickness on the incidence of acute pulmonary vein reconnection after Ablation Index-guided atrial fibrillation ablation.

Although Ablation Index (AI)-guided ablation facilitates creation of lesions of consistent depth, pulmonary vein (PV) reconnection is still commonly observed after AI-guided pulmonary vein isolation (PVI). The present study aimed to investigate the impact of local left atrial wall thickness on the incidence of acute PV reconnection after AI-guided atrial fibrillation (AF) ablation. Seventy patients (63% paroxysmal AF, 67% male, mean age 63±8years) who underwent preprocedural CT imaging and AI-guided AF ablation were studied. Occurrence of acute PV reconnection after initial PVI was assessed after a 30-minute waiting period. Ablation procedures were retrospectively analyzed and each ablation circle was subdivided into 8 segments. Minimum AI, force-time integral, contact force, ablation duration, power, impedance drop and maximum interlesion distance were determined for each segment. PV antrum wall thickness was assessed for each segment on reconstructed CT images based on patient-specific thresholds in Hounsfield Units. Acute reconnection occurred in 27/1120 segments (2%, 15 anterior/roof, 12 posterior/inferior) in 19/140 ablation circles (14%). Reconnected segments were characterized by a greater local atrial wall thickness, both in anterior/roof (1.87±0.42 vs. 1.54±0.42mm; p<0.01) and posterior/inferior (1.43±0.20 vs. 1.16±0.22mm; p<0.01) segments. Minimum AI, force-time integral, contact force, ablation duration, power, impedance drop and maximum interlesion distance were not associated with acute reconnection. Local atrial wall thickness is associated with acute pulmonary vein reconnection after AI-guided PVI. Individualized AI targets based on local wall thickness may be of use to create transmural ablation lesions and prevent PV reconnection after PVI.

Intraprocedural guidance for recanalization of post-thrombotic venous lesions using live overlay of center lines from pre-operative cross-sectional imaging: a preliminary experience

PurposePre-procedural contrast-enhanced CT and MRI imaging is typically acquired prior to deep venous recanalization procedures for post-thrombotic syndrome. This technical note reports the utility of live-overlay of augmented centerlines extracted from pre-procedural CT and MRI imaging in facilitating fluoroscopic-guided recanalization of post-thrombotic venous lesions.Methods and materialsSix patients with pre-procedural CT or MR venography data were incorporated into a commercially available 3D overlay software (Vessel Assist, GE Healthcare, Buc, France) during venous disease interventions for post-thrombotic venous lesions. Procedures were performed on the GE Discovery IGS 740 fluoroscopy system. After manual determination of the vasculature from preprocedural CT or MR, centerlines were created representing the location and trajectory of the vessels. Steps showcasing the creation of centerlines and their representation during overlay with real-time fluoroscopic guidance in these cases are outlined. Time required to cross the post-thrombotic and occlusive venous segments were reviewed.ResultsAll iliocaval recanalization procedures were successfully performed utilizing vessel centerline 3D overlay. In one case where occlusion extended to the femoral vein, mis-registration was identified over the femoral anatomy due to a complex leg rotation compared to pre-procedural imaging. No procedural complications related to utilization of software were noted. Average crossing time for occlusions was 3.4 min (range 1.6–5.2).Conclusion3D overlay with vessel tracking from pre-procedural CT and MRI imaging is technically feasible and assists in catheter navigation for post-thrombotic venous segments. While results from these preliminary experiences support the continued use of this technology, further prospective and comparative evaluation of this technique is warranted to assess for added value in technical success, reductions in procedure time or reductions in radiation exposure.

Leukoaraiosis and collateral blood flow in stroke patients with anterior circulation large vessel occlusion

BackgroundLeukoaraiosis and collateral blood flow are processes that involve small vessels, the former related to flow within the deep perforating arterioles and the latter involving the small, cortical pial-pial connections,...

Cardiac CT and Structural Heart Disease Interventions (Non-TAVI)

The use of cardiac CT is well established in the TAVR sphere and gaining traction as an integral part of pre-procedural planning for left 13 atrial appendage closure (LAAC) and transcatheter mitral valve replacement (TMVR. We aim to review the recent evidence regarding the accuracy of cardiac CT for left atrial sizing and device selection and discuss the contribution of cardiac CT to decreasing complication rates in real-world experience as compared with clinical trials. Pre-procedural CT imaging has evolved to become an integral part of LAA closure and TMVR. For LAA closure, CT imaging provides detailed anatomic assessment of the LAA and surrounding structures and accurate measurements for device sizing. These can facilitate device and equipment selection and enhance safety and outcomes with intraprocedural guidance with transesophageal echocardiography or intracardiac echocardiography. For TMVR, pre-procedural CT is necessary to assess the potential risk of LVOT obstruction and determine device sizing. Such assessments can help pre-plan the potential need for adjunctive strategies to lower the risk of LVOT obstruction. CT imaging has gained important roles in the field of structural interventions, and understanding how to utilize this tool is an important skill to acquire as a contemporary comprehensive interventionist. Pre-procedural CT imaging has evolved to become an integral part of LAA closure and TMVR.

P2836Role of pre-procedural CT-imaging on catheter ablation in patients with atrial fibrillation: procedural outcomes and radiological exposure

Abstract Introduction Cardiac computerized tomography (CT) is commonly used to study left atrial (LA) and pulmonary veins (PVs) anatomy before atrial fibrillation (AF) ablation. However, it remains unclear whether pre-procedural imaging actually is associated with an improvement of efficiency, efficacy, and safety. Purpose Aim of the the study was to determine the impact of pre-procedural imaging using CT with 3-D reconstruction on procedural outcomes and radiological exposure in patients who undergo radiofrequency catheter ablation (RFA) to eliminate AF. Methods In this registry, 493 consecutive patients (age 62±8 years, 70% male) with paroxysmal (316) or persistent (177) AF who underwent RFA were included. A CT scan was obtained in 324 (66%) patients (CT Group) prior to RFA, while 169 (34%) didn't have any pre-procedural imaging (No-CT Group). Antral PVs isolation was performed in all patients along using an open-irrigation-tip catheter with a 3-D electroanatomical navigation system. Additional ablation applications were targeted if required. Procedural outcome, including radiological exposure, and clinical outcomes were compared among patients who underwent RFA with (CT-Group) and without (No CT-Group) pre-procedural imaging. Results Acute PV isolation was obtained in all patients. Additional ablation targets were targeted along the CTI (71/324 [22%] vs. 40/169 [24%], P=NS), the roof line (74/324 [23%] vs. 40/169 [24%], P=NS), the mitral isthmus (33/324 [10%] vs. 12/169 [7%], P=NS) and CFAEs (28/324 [8.6%] vs. 12/169 [7.1%], P=NS), without significant differences among groups. Complication rate were comparable between CT and No CT patients (4.3% vs 3%, P=0.7). In one Redo procedure of the No-CT Group, for the impossibility of identifying left PVs, a 3D LA fluoro-angiography was performed, which confirmed a left PVs occlusion. (Figure) No differences were observed about mean duration of the procedure (231±60 vs 233±58 min, P=0.7) and fluoroscopy time (13±10 vs 13±8 min, P=0.6) between groups. Cumulative radiation dose resulted significantly higher in the CT-Group (8.9±24 vs 4.8±15 mSV, P=0.02). Compared to paroxistical AF, persistent AF patients showed a comparable procedural-ED (6.6±26 vs 6±19, P=0.8) but with an higher CT-ED (1.7±2.9 vs 1.1±1.9, P=0.01).At 1 year, 227/324 (70%) and 119/169 (70%) of the patients who did and did not have pre-procedural imaging were free from AF (P = NS). Figure 1 Conclusions Pre-procedural CT does not improve safety and efficacy of AF ablation, increasing significantly the cumulative radiological exposure. Considering that patients candidate to AF ablation are often young, the cumulative radiation dose per life span and radiation dose reduction strategies should remain a matter of concern for doctors. Acknowledgement/Funding None

CT angiography prior to TAVI procedure using third-generation scanner with wide volume coverage: feasibility, renal safety and diagnostic accuracy for coronary tree.

To evaluate feasibility, image quality and accuracy of a reduced contrast volume protocol for pre-procedural CT imaging in transcatheter aortic valve implantation (TAVI) using a third generation wide array CT scanner. 115 consecutive patients (51F, mean age 82.5 ± 6.2 y, mean BMI 26.7 ± 3.6) referred for TAVI were examined with wide-array CT scanner with a combined scan protocol and a total amount of 50 ml contrast agent. A 4-point visual scale (4-1) was used to assess image quality . Contrast attenuation values (HU) and contrast-to-noise ratio (CNR) were measured at the level of the aortic root, ascending/descending aorta, subrenal aorta and at the level of right and left common femoral arteries. Coronary tree was assessed and compared with invasive coronary angiography (ICA). Aortic annulus measurements were compared with final procedural results. Patients creatinine was monitored at the baseline and 72 h after procedure. Median quality score value was >3. Mean CNR at the level of the aortic root, ascending/descending aorta, subrenal aorta and at the level of right and left common femoral arteries were 14.8 ± 2.3, 15.7 ± 1.7, 14.9 ± 3.1, 15.8 ± 4.7, 20.3 ± 9.9, 20.8 ± 6.9 respectively. Only 1 patient had moderate paravalvular regurgitation. In comparison with ICA for coronary assessment CTA showed in a segment based analysis sensitivity, specificity, negative predictive value, positive predictive value and accuracy of 97, 85, 99,62 and 88% respectively. Mean creatinine before CT and 72 h after procedure were 1.21 ± 0.52 and1.22 ± 0.49 mg dl-1. Mean DLP was 442.4 ± 21.2 mGy/cm. CT with low contrast volume is feasible and clinically useful, allowing precise pre-procedural TAVI planning with accurate assessment of coronary tree. third generation CT scanner with whole heart coverage allows examinations for assessment of aorta and coronary arteries in TAVI planning using low dose of contrast medium maintaining good quality and high diagnostic accuracy.

Contrast volume reduction using third generation dual source computed tomography for the evaluation of patients prior to transcatheter aortic valve implantation.

Chronic renal failure is common in patients referred for transcatheter aortic valve implantation (TAVI). CT angiography is recommended and provides crucial information prior to TAVI. We evaluated the feasibility of a reduced contrast volume protocol for pre-procedural CT imaging. Forty consecutive patients were examined with prospectively ECG-triggered high-pitch spiral acquisition using a novel third-generation dual-source CT system; 38ml contrast agent was used. Image quality was graded on a visual scale (1-4). Contrast attenuation was measured at the level of the aortic root and at the iliac bifurcation. Mean patient age was 82 ± 6years (23 males; 58%). Mean attenuation/average image quality was 285 ± 60 HU/1.5 at the aortic annulus compared to 289 ± 74 HU/1.8 at the iliac bifurcation (p = 0.77/p = 0.29). Mean estimated effective radiation dose was 2.9 ± 0.3mSv. A repeat acquisition was necessary in one patient due to image quality. Out of the 35 patients who underwent TAVI, 31 (89%) patients had no or mild aortic regurgitation. Thirty-two (91%) patients were discharged successfully. Pre-procedural CTA with a total of 38ml contrast volume is feasible and clinically useful, using third-generation dual-source CT, allowing comprehensive imaging for procedural success. • Reduction of contrast agent volume is crucial in patients with chronic renal failure. • Novel third-generation computed tomography helps to reduce contrast agent volume. • Pre-procedural CT allows comprehensive imaging for procedural success before heart valve implantation. • A low-contrast CT protocol is feasible for pre-procedural TAVI planning.

Abstract 5663: Intracardiac Echocardiography From Within the Left Atrium Improves the Accuracy of Image Integration During Catheter Ablation of Atrial Fibrillation

Background: Intracardiac echocardiography (ICE) can be integrated with pre-procedural CT or MR imaging to direct catheter ablation of atrial fibrillation (AF). Prior work has described ICE imaging of the left atrium (LA) with the ICE probe in the RA, but it is feasible to image the LA from an ICE probe placed directly into the LA via a trans-septal puncture performed for the mapping/ablation procedure. The purpose of this study was to determine whether direct LA imaging with ICE results in improved image integration during AF ablation compared with LA imaging indirectly from the RA. Methods: Twenty-five consecutive patients undergoing an AF ablation procedure with the CARTO-Sound system were studied. A 10 French phased array catheter with an embedded CARTO navigation sensor was employed to provide 2D echocardiogram images of the LA - 13 patients underwent imaging from the RA alone and 12 patients from the LA. The accuracy of the image integration was assessed by the average integration error after surface registration and the requirement to take supplementary electroanatomic mapping points to obtain acceptable image integration. Results: Twenty-five patients (56% paroxysmal AF, average LA size = 42±8 mm, average EF = 63±10 %) were examined. There was no difference in the time or number of ultrasound contours required to create a LA anatomic map with ICE imaging from the RA versus the LA (24±17min vs. 24±25min, P=1.0, 24±16 contours vs. 29±18 contours, P=0.5). The average integration error for all patients was 2.19±0.59mm. Direct LA imaging was associated with improved integration error compared to indirect LA imaging from the RA (1.85±0.33mm versus 2.51±0.62mm, P=0.004). Image integration using RA acquired LA images had a tendency to be less accurate resulting in the primary operator acquiring additional registration points to supplement the registration process (patients requiring additional registration points for registration: 3/12 for LA imaging versus 9/13 for RA imaging of the LA, P=0.05). Conclusion: Direct ICE imaging from within the LA is feasible and associated with improved accuracy of image integration during AF ablation.

Intraprocedural Volume Imaging of the Left Atrium and Pulmonary Veins with Rotational X‐Ray Angiography: Implications for Catheter Ablation of Atrial Fibrillation

The use of preprocedural CT or MR imaging to generate patient-specific cardiac anatomy greatly facilitates catheter ablation of the left atrium and pulmonary veins (LA-PVs) to treat atrial fibrillation (AF). This report details the accuracy and utility of an intraprocedural means to generate 3-D volumetric renderings of the LA-PV anatomy: contrast-enhanced rotational X-ray angiography (3DRA). Preprocedural CT or MR imaging and intraprocedural rotational angiography was performed in 42 patients undergoing AF ablation procedures. Initially, pulmonary artery (PA) bolus-chase contrast injections were performed (20 mL, 20 mL/s) to establish pulmonary transit time and cardiac isocentering. Depending on cardiac size, either a single PA injection (80-100 mL, 20 mL/s) or two separate dedicated left/right PA branch injections were performed (60 mL each, 20 mL/s). For the latter, the two volumes of the left/right portions of the LA-PVs were registered and fused. LA-PV 3DRA images were assessed qualitatively and quantitatively in comparison with CT/MR images. The majority of the 3DRA acquisitions (71%) were deemed at least "useful" in delineating the LA-PV anatomy. The LA appendage was delineated in 57% of the cases. A blinded quantitative comparison of PV ostial diameters resulted in an absolute difference of only 2.7 +/- 2.3 mm, 2.2 +/- 1.8 mm, 2.4 +/- 2.2 mm, and 2.2 +/- 2.3 mm for the left-superior, left-inferior, right-superior, and right-inferior PVs, respectively. The feasibility for registering the 3DRA image with real-time electroanatomical mapping was also demonstrated. Intraprocedural contrast-enhanced rotational angiography provides volumetric 3-D images of the LA-PVs of comparable diagnostic value to dedicated preprocedural CT/MR imaging.

P2-43: Pre-procedural 3D CT imaging of the left atrial appendage: Implications for the selection and deployment of left atrial appendage exclusion devices

Left atrial appendage exclusion devices may offer an alternative to standard therapy in AF patients with contraindications to anticoagulation. Currently, intra-procedural trans-esophageal echocardiography (TEE) and fluoroscopy are used to visualize the anatomy of the left atrial appendage and guide selection and placement of the device. This technique is limited in that the 2D representation of these structures may introduce error into the estimation of the orifice size and that TEE often requires general anesthesia.

Impact of multidetector CT hepatic arteriography on the planning of chemoembolization treatment of hepatocellular carcinoma.

We examined the impact of the increased sensitivity for hypervascular masses of multidetector CT hepatic arteriography on treatment decisions involving selective chemoembolization of hepatocellular carcinomas. Thirty patients were referred for chemoembolization of unresectable hepatocellular carcinoma. Initial selective chemoembolization plans were formulated on the basis of diagnostic biphasic CT or MR imaging. Ultrafast CT hepatic arteriography was performed using a multidetector CT scanner and selective contrast material injection into the hepatic artery. The entire liver was scanned in a single breath-hold of approximately 20 sec with a slice thickness of 1 mm. Lesions and their arterial supplies were identified, and these data were immediately used to formulate a final plan for chemoembolization. Hypervascular masses were detected in 29 patients. In 16 (53%) of the patients, preprocedural CT or MR imaging underestimated the number of lesions. In nine (30%) of these 16 patients, the additional lesions were detected only on CT hepatic arteriography, not on conventional angiography. CT hepatic arteriography findings had a major impact on planning the way in which chemoembolization treatment was performed. In three of the nine patients, the previously undetected lesions were treated with additional superselective chemoembolization. In the other six patients, chemoembolization was performed less selectively than originally planned. Primarily because of the high sensitivity of multidetector CT hepatic arteriography in revealing small and multifocal hepatomas, findings of this modality frequently alter treatment plans involving selective administration of chemoembolic material.