First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism.

PURPOSE: To prospectively evaluate the initial human experience with an absorbable vena cava filter designed for transient protection from pulmonary embolism (PE). MATERIALS AND METHODS: This was a prospective, single-arm, first-in-human study of 8 patients with elevated risk of venous thromboembolism (VTE). Seven absorbable IVC filters (made of polydioxanone that breaks down into H2O and CO2 in 6 mo) were placed prophylactically before orthopedic (n = 5) and gynecologic (n = 2) surgeries, and 1 was placed in a case of deep vein thrombosis. Subjects underwent CT cavography and abdominal radiography before and 5, 11, and 36 weeks after filter placement to assess filter migration, embolization, perforation, and caval thrombosis and/or stenosis. Potential PE was assessed immediately before and 5 weeks after filter placement by pulmonary CT angiography. RESULTS: No symptomatic PE was reported throughout the study or detected at the planned 5-week follow-up. No filter migration was detected based on the fixed location of the radiopaque markers (attached to the stent section of the filter) relative to the vertebral bodies. No filter embolization or caval perforation was detected, and no caval stenosis was observed. Throughout the study, no filter-related adverse events were reported. CONCLUSIONS: Implantation of an absorbable vena cava filter in a limited number of human subjects resulted in 100% clinical success. One planned deployment was aborted as a result of stenotic pelvic veins, resulting in 89% technical success. No PE or filter-related adverse events were observed.

Are fibroid and bony pelvis characteristics associated with urinary and pelvic symptom severity?

BACKGROUND: Urinary and pelvic floor symptoms often are attributed to size and location of uterine fibroid tumors. However, direct supporting evidence that links increased size to worsening symptoms is scant and limited to ultrasound evaluation of fibroid tumors. Because management of fibroid tumors is targeted towards symptomatic relief, the identification of fibroid and pelvic characteristics that are associated with worse symptoms is vital to the optimization of therapies and prevention needless interventions. OBJECTIVE: We examined the correlation between urinary, pelvic floor and fibroid symptoms, and fibroid size and location using precise uterine fibroid and bony pelvis characteristics that were obtained from magnetic resonance imaging. STUDY DESIGN: A retrospective review (2013-2017) of a multidisciplinary fibroid clinic identified 338 women who had been examined via pelvic magnetic resonance imaging, Pelvic Floor Distress Inventory questionnaire (score 0-300), and a Uterine Fibroid Symptoms questionnaire (score 1-100). Multiple linear regression analysis was used to assess the influence of clinical factors and magnetic resonance imaging findings on scaled Pelvic Floor Distress Inventory and Uterine Fibroid Symptoms scores. Data were analyzed with statistical software. RESULTS: Our cohort of 338 women had a median Pelvic Floor Distress Inventory of 72.7 (interquartile range, 41-112.3). Increased Pelvic Floor Distress Inventory score was associated with clinical factors of higher body mass index (P<.001), noncommercial insurance (P<.001), increased parity (P=.001), and a history of incontinence surgery (P=.003). Uterine volume, dominant fibroid volume, dimension and location, and fibroid tumor location relative to the bony pelvis structure did not reach significance when compared with pelvic floor symptom severity. The mean Uterine Fibroid Symptoms score was 52.0 (standard deviation, 23.5). An increased Uterine Fibroid Symptoms score was associated with dominant submucosal fibroid tumors (P=.011), body mass index (P<.0016), and a clinical history of anemia (P<.001) or any hormonal treatment for fibroid tumors (P=.009). CONCLUSION: Contrary to common belief, in this cohort of women who sought fibroid care, size and position of fibroid tumors or uterus were not associated with pelvic floor symptom severity. Whereas, bleeding symptom severity was associated with dominant submucosal fibroid tumor and previous hormonal treatment. Careful attention to clinical factors such as body mass index and medical history is recommended when pelvic floor symptoms are evaluated in women with uterine fibroid tumors.

Evaluation of the routine use of pelvic MRI in women presenting with symptomatic uterine fibroids: When is pelvic MRI useful?

BACKGROUND: Pelvic ultrasound (US) diagnosis of uterine fibroids may overlook coexisting gynecological conditions that contribute to women's symptoms. PURPOSE: To determine the added value of pelvic MRI for women diagnosed with symptomatic fibroids by US, and to identify clinical factors associated with additional MRI findings. STUDY TYPE: Retrospective observational study. POPULATION: In all, 367 consecutive women with fibroids diagnosed by US and referred to our multidisciplinary fibroid center between 2013-2017. FIELD STRENGTH/SEQUENCE: All patients had both pelvic US and MRI prior to their consultations. MRIs were performed at 1.5 T or 3 T and included multiplanar T2 -weighted sequences, and precontrast and postcontrast T1 -weighted imaging. ASSESSMENT: Demographics, symptoms, uterine fibroid symptom severity scores, and health-related quality of life scores, as well as imaging findings were evaluated. STATISTICAL TESTS: Patients were separated into two subgroups according to whether MRI provided additional findings to the initial US. Univariate and multivariate regression analyses were performed. RESULTS: Pelvic MRI provided additional information in 162 patients (44%; 95% confidence interval [CI] 39-49%). The most common significant findings were adenomyosis (22%), endometriosis (17%), and partially endocavitary fibroids (15%). Women with pelvic pain, health-related quality of life scores less than 30 out of 100, or multiple fibroids visualized on US had greater odds of additional MRI findings (odds ratio [OR] 1.68, 2.26, 1.63; P = 0.02, 0.004, 0.03, respectively), while nulliparous women had reduced odds (OR 0.55, P = 0.01). Patients with additional MRI findings were treated less often with uterine fibroid embolization (14% vs. 36%, P < 0.001) or MR-guided focused US (1% vs. 5%, P = 0.04), and more often with medical management (17% vs. 8%, P = 0.01). DATA CONCLUSION: Pelvic MRI revealed additional findings in more than 40% of women presenting with symptoms initially ascribed to fibroids by US. Further evaluation using MRI is particularly useful for parous women with pelvic pain, poor quality of life scores, and/or multiple fibroids. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019.

Transesophageal Echocardiographic Observation of Caval Thrombus Followed by Intraoperative Placement of Inferior Vena Cava Filter for Presumed Pulmonary Embolism During Cesarean Hysterectomy for Placenta Percreta: A Case Report.

During a cesarean hysterectomy for placenta percreta, transesophageal echocardiography was used to monitor volume status and guide resuscitation. After delivery of the neonate but before massive surgical hemorrhage, a thrombus appeared in the inferior vena cava. Roughly 3 hours later, the patient had hemodynamic changes consistent with an intraoperative pulmonary embolism. Boluses of epinephrine stabilized the patient. An inferior vena cava filter was placed via an in situ internal jugular central venous cannula to prevent further embolic events. We believe transesophageal echocardiography is a useful monitor during surgery for placenta percreta.

Yellow nail syndrome with chylothorax after coronary artery bypass grafting.

BACKGROUND: Yellow nail syndrome is a rare condition considered secondary to functional anomalies of lymphatic drainage. Yellow nail syndrome is diagnosed through the triad of intrathoracic findings (30% being pleural effusions), nail discoloration, and lymphedema, with any two features sufficient for diagnosis. We report the second case of post-operative yellow nail syndrome. CASE PRESENTATION: After coronary artery bypass grafting, our patient presented with chylothorax on post-operative day 13 and yellow toenail discoloration on post-operative day 28, diagnosing yellow nail syndrome. Initial conservative management with pigtail catheter drainage and low-fat diet with medium-chain triglycerides reduced chylous drainage from 350 mL/day on post-operative day 14 to < 100 mL/day on post-operative day 17. However, by post-operative day 18, drainage returned to 350 mL/day that persisted despite attempts to readjust the catheter position, replacement of catheter with chest tube, and transition to total parenteral nutrition and octreotide while nil per os. Lymphangiogram on post-operative day 32 did not identify the thoracic duct or cisterna chyli, precluding embolization. Talc and doxycycline pleurodeses performed on post-operative days 33 and 38, respectively, resolved his chylothorax and nail discoloration. CONCLUSIONS: Both yellow nail syndrome and chylothorax as a complication of coronary artery bypass grafting are rare entities. The proposed mechanism of post-operative chylothorax is iatrogenic injury to thoracic duct or collateral lymphatic vessels. Diagnosing yellow nail syndrome in patients with post-operative chylothorax (through co-existing yellow nail discoloration and/or lymphedema) may suggest predisposition to impaired lymphatic drainage, portending a difficult recovery and potentially indicating need for surgical management.

Treatment of Low-Flow Vascular Malformations of the Extremities Using MR-Guided High Intensity Focused Ultrasound: Preliminary Experience.

Five patients with painful vascular malformations of the extremities that were refractory to standard treatment and were confirmed as low-flow malformations on dynamic contrast-enhanced magnetic resonance (MR) imaging were treated with MR imaging-guided high intensity focused ultrasound. Daily maximum numeric rating scale scores for pain improved from 8.4 ± 1.5 to 1.6 ± 2.2 (P = .004) at a median follow-up of 9 months (range, 4-36 mo). The size of the vascular malformations decreased on follow-up MR imaging (median enhancing volume, 8.2 mL [0.7-10.1 mL] before treatment; 0 mL [0-2.3 mL] after treatment; P = .018) at a median follow-up of 5 months (range, 3-36 mo). No complications occurred.

Administering Blood Products Before Selected Interventional Radiology Procedures: Developing, Applying, and Monitoring a Standardized Protocol.

PURPOSE: To apply and monitor a single institution's adherence to internally established guidelines for the preoperative administration of platelets and/or fresh frozen plasma (FFP) before a specified subset of minimally invasive interventional radiology (IR) procedures. MATERIALS AND METHODS: Beginning in December 2008, we implemented a set of restrictive guidelines for preoperative platelet and/or FFP administration before IR procedures at a single academic hospital. Basing our program on the methodology of Lean Six Sigma, we compared the number and appropriateness of transfusions between the months of January and October in 2008 (prepolicy), again in 2010 (postpolicy), and finally in 2015 (follow-up). Patients with a platelet count less than or equal to 50,000 or an international normalized ratio greater than or equal to 1.7 met criteria for receiving platelets or FFP, respectively, before their IR procedure. For all three periods, we compared the rates of transfusion, hemorrhagic complications, and proportion of appropriate versus inappropriate blood product administration (BPA) per our guidelines. RESULTS: There was a significant increase in the number of appropriate BPAs between 2008 and 2010 from 58% to 76% (P = .021). Between 2010 and 2015, the rate trended up further, from 76% to 88% (P = .051). Overall, between 2008 and 2015, the improvement from 58% to 88% was significant (P < .001). The rate of hemorrhagic complications was extremely low in all three groups. CONCLUSION: Restrictive guidelines for receiving platelets and FFP administrations before IR procedures can sustainably decrease the rate of overall BPA while increasing the proportion of appropriate BPA without impacting the rate of hemorrhagic complications.

Treatment of complex periorbital venolymphatic malformation in a neonate with a combination therapy of sirolimus and prednisolone.

Venolymphatic malformations (VLMs) are vascular anomalies consisting of both veins and lymph vessels. A 2-week-old newborn presented with large VLMs on the left forehead, temple, preauricular area, and orbit. Patient was at imminent risk for permanent vision loss due to a localized mass effect. Surgical excision or debulking was contraindicated due to its complexity and proximity to the left eye, and the patient failed to respond to the sildenafil treatment and sclerotherapy. Patient was subsequently started on oral sirolimus 0.8 mg/m(2) twice daily in combination with prednisolone 2 mg/kg daily. The patient had an excellent therapeutic outcome for 7 months with complete preservation of vision before treatment was discontinued. However, 2 months after the medical treatments were discontinued, her VLM rebounded. She responded to the combination therapy again after a failed treatment with the mTOR inhibitor alone. This case demonstrates that the sirolimus and prednisolone combination therapy could be beneficial for treatment of complex VLM intractable to other treatments.

Optimal imaging surveillance schedules after liver-directed therapy for hepatocellular carcinoma.

PURPOSE: To optimize surveillance schedules for the detection of recurrent hepatocellular carcinoma (HCC) after liver-directed therapy. MATERIALS AND METHODS: New methods have emerged that allow quantitative analysis and optimization of surveillance schedules for diseases with substantial rates of recurrence such as HCC. These methods were applied to 1,766 consecutive chemoembolization, radioembolization, and radiofrequency ablation procedures performed on 910 patients between 2006 and 2011. Computed tomography or magnetic resonance imaging performed just before repeat therapy was set as the time of "recurrence," which included residual and locally recurrent tumor as well as new liver tumors. Time-to-recurrence distribution was estimated by Kaplan-Meier method. Average diagnostic delay (time between recurrence and detection) was calculated for each proposed surveillance schedule using the time-to-recurrence distribution. An optimized surveillance schedule could then be derived to minimize the average diagnostic delay. RESULTS: Recurrence is 6.5 times more likely in the first year after treatment than in the second. Therefore, screening should be much more frequent in the first year. For eight time points in the first 2 years of follow-up, the optimal schedule is 2, 4, 6, 8, 11, 14, 18, and 24 months. This schedule reduces diagnostic delay compared with published schedules and is cost-effective. CONCLUSIONS: The calculated optimal surveillance schedules include shorter-interval follow-up when there is a higher probability of recurrence and longer-interval follow-up when there is a lower probability. Cost can be optimized for a specified acceptable diagnostic delay or diagnostic delay can be optimized within a specified acceptable cost.

Tract embolization with gelatin sponge slurry for prevention of pneumothorax after percutaneous computed tomography-guided lung biopsy.

PURPOSE: To determine the effect of embolization with absorbable gelatin sponge slurry on the incidence of pneumothorax (PTX) and need for chest tube placement after percutaneous lung biopsy. MATERIALS AND METHODS: Seven hundred fifty-two percutaneous lung biopsy procedures and fiducial seed placements were performed using computed tomography (CT)-guidance at a single institution. A retrospective review was performed including 145 patients with embolization (19.28%) of the tract with gelatin sponge slurry during needle withdrawal and 607 patients who did not undergo tract embolization. Patient- and lesion-related characteristics were collected through the electronic health record and PACS. Outcome measures included the occurrence of PTX during or after the biopsy procedure and the need for chest tube placement. Analysis was performed by multivariate logistic regression. RESULTS: Although tract embolization did not significantly decrease the chances of developing PTX (p = 0.06), it did decrease the likelihood of progressing to requiring chest tube insertion. Without tract embolization, 10.7% of cases required a chest tube, whereas only 6.9% of the patients whose tract was embolized needed a chest tube (p = 0.01). A history of emphysema was associated with 151% increased odds of PTX requiring chest tube placement after lung biopsy (p = 0.009). Tract length >24 mm was associated with a 262% increase in the odds of requiring chest tube placement (p = 0.003). CONCLUSION: Embolization of the needle tract during percutaneous lung biopsy with gelfoam slurry significantly decreased the odds of requiring a chest tube for PTX and should be considered for all patients, particularly those with emphysema and deep lesions.

Correlation of the diameter of the left common iliac vein with the risk of lower-extremity deep venous thrombosis.

PURPOSE: Compression of the left common iliac vein (CIV; LCIV) is a known risk factor for lower-extremity deep vein thrombosis (DVT). This study was performed to model the probability of DVT based on LCIV diameter and apply this to a quantitative DVT risk factor scoring system. MATERIALS AND METHODS: Medical records were used to identify female patients younger than 45 years of age who were diagnosed with lower-extremity DVT (n = 21) and age-matched control subjects (n = 26) who presented to the emergency department with abdominal pain. Minimum CIV diameters were measured on computed tomography. Based on published reporting standards, 13 risk factors were scored for patients diagnosed with left-sided DVT and for control subjects. The association between vein diameter and DVT was examined by Mann-Whitney test. Odds of DVT based on vein diameter was assessed by logistic regression. RESULTS: Mean minimum LCIV diameters were 4.0 mm for patients with DVT and 6.5 mm for patients without DVT (P = .001). The odds of left DVT increased by a factor of 1.68 for each millimeter decrease in LCIV diameter (odds ratio = 1.68; P = .006; 95% confidence interval, 1.16-2.43). As the risk factor score increased, the relationship between diameter and risk for DVT became stronger; identical LCIV diameters were associated wtih a higher probability of developing DVT if the risk factor score was higher. CONCLUSIONS: Stenosis of the LCIV was found to be a strong independent risk factor for development of DVT. Moreover, each millimeter decrease in CIV diameter increased the odds of DVT by a factor of 1.68.

Applying a structured innovation process to interventional radiology: a single-center experience.

PURPOSE: To determine the feasibility and efficacy of applying an established innovation process to an active academic interventional radiology (IR) practice. MATERIALS AND METHODS: The Stanford Biodesign Medical Technology Innovation Process was used as the innovation template. Over a 4-month period, seven IR faculty and four IR fellow physicians recorded observations. These observations were converted into need statements. One particular need relating to gastrostomy tubes was diligently screened and was the subject of a single formal brainstorming session. RESULTS: Investigators collected 82 observations, 34 by faculty and 48 by fellows. The categories that generated the most observations were enteral feeding (n = 9, 11%), biopsy (n = 8, 10%), chest tubes (n = 6, 7%), chemoembolization and radioembolization (n = 6, 7%), and biliary interventions (n = 5, 6%). The output from the screening on the gastrostomy tube need was a specification sheet that served as a guidance document for the subsequent brainstorming session. The brainstorming session produced 10 concepts under three separate categories. CONCLUSIONS: This formalized innovation process generated numerous observations and ultimately 10 concepts to potentially to solve a significant clinical need, suggesting that a structured process can help guide an IR practice interested in medical innovation.

Complex retrieval of embedded IVC filters: alternative techniques and histologic tissue analysis.

PURPOSE: We evaluated the safety and effectiveness of alternative endovascular methods to retrieve embedded optional and permanent filters in order to manage or reduce risk of long-term complications from implantation. Histologic tissue analysis was performed to elucidate the pathologic effects of chronic filter implantation. METHODS: We studied the safety and effectiveness of alternative endovascular methods for removing embedded inferior vena cava (IVC) filters in 10 consecutive patients over 12 months. Indications for retrieval were symptomatic chronic IVC occlusion, caval and aortic perforation, and/or acute PE (pulmonary embolism) from filter-related thrombus. Retrieval was also performed to reduce risk of complications from long-term filter implantation and to eliminate the need for lifelong anticoagulation. All retrieved specimens were sent for histologic analysis. RESULTS: Retrieval was successful in all 10 patients. Filter types and implantation times were as follows: one Venatech (1,495 days), one Simon-Nitinol (1,485 days), one Optease (300 days), one G2 (416 days), five Günther-Tulip (GTF; mean 606 days, range 154-1,010 days), and one Celect (124 days). There were no procedural complications or adverse events at a mean follow-up of 304 days after removal (range 196-529 days). Histology revealed scant native intima surrounded by a predominance of neointimal hyperplasia and dense fibrosis in all specimens. Histologic evidence of photothermal tissue ablation was confirmed in three laser-treated specimens. CONCLUSION: Complex retrieval methods can now be used in select patients to safely remove embedded optional and permanent IVC filters previously considered irretrievable. Neointimal hyperplasia and dense fibrosis are the major components that must be separated to achieve successful retrieval of chronic filter implants.

Percutaneous cholecystostomy for acute cholecystitis: ten-year experience.

PURPOSE: To review the clinical course of patients with acute cholecystitis treated by percutaneous cholecystostomy, and to identify risk factors retrospectively that predict outcome. MATERIALS AND METHODS: A total of 106 patients diagnosed with acute cholecystitis were treated by percutaneous cholecystostomy during a 10-year period. Seventy-one (67%) presented to the emergency department (ED) specifically for acute cholecystitis, and 35 (23%) were inpatients previously admitted for other conditions. Outcomes of the two groups were compared with respect to severity of illness, leukocytosis, bile culture, liver function tests, imaging features, time intervals from onset of symptoms to medical and percutaneous intervention, and whether surgical cholecystectomy was later performed. RESULTS: Overall, 72 patients (68%) showed an improvement clinically, whereas 34 (32%) showed no improvement or a clinically worsened condition after cholecystostomy. Patients who presented to the ED primarily with acute cholecystitis fared better (84% of patients showed improvement) than inpatients (34% showed improvement; P < .0001). Gallstones were identified in 54% of patients who presented to the ED, whereas acalculous cholecystitis was more commonly diagnosed in inpatients (54%). Patients with sepsis had worse outcomes overall (P < .0001). Bacterial bile cultures were analyzed in 95% of patients and showed positive results in 52%, with no overall effect on outcome. There was no correlation between the time of onset of symptoms until antibiotic therapy or cholecystostomy in either group. Long-term outcomes for both groups were better for those who later underwent cholecystectomy (P < .0001). CONCLUSIONS: Outcomes after percutaneous cholecystostomy for acute cholecystitis are better when the disease is primary and not precipitated by concurrent illness.

Uteroenteric fistula resulting from fibroid expulsion after uterine fibroid embolization: case report and review of the literature.

A 44-year-old woman underwent uncomplicated uterine fibroid embolization (UFE) for menstrual and bulk-related symptoms in an enlarged, myomatous uterus. After surgery, she spontaneously sloughed a large mass of fibroids that arrested in the cervical canal during passage. Four days after gynecological extraction, she developed copious vaginal discharge that contained enteric contents. Contrast-enhanced computed tomography (CT) demonstrated a fistula between the small bowel and the uterus. She subsequently underwent hysterectomy, left oophorectomy, and small-bowel resection. Her postoperative recovery was uneventful.

Embolization of parasitized extrahepatic arteries to reestablish intrahepatic arterial supply to tumors before yttrium-90 radioembolization.

PURPOSE: To perform embolization of parasitized extrahepatic arteries (EHAs) before radioembolization to reestablish intrahepatic arterial supply to large, peripheral tumors, and to evaluate the technical and clinical outcomes of this intervention. MATERIALS AND METHODS: Among 201 patients retrospectively analyzed, embolization of 73 parasitized EHAs in 35 patients was performed. Most embolization procedures were performed during preparatory angiography using large particles and coils. Digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m macroaggregated albumin ((99m)TcMAA) scintigraphy were used to evaluate the immediate perfusion via intrahepatic collateral channels of target tumor areas previously supplied by parasitized EHAs. Follow-up imaging of differential regional tumor response was used to evaluate microsphere distribution and clinical outcome. RESULTS: After embolization, reestablishment of intrahepatic arterial supply was confirmed by both DSA and C-arm CT in 94% of territories and by scintigraphy in 96%. In 32% of patients, the differential response of treatment could not be evaluated because of uniform disease progression. However, symmetric regional tumor response in 94% of evaluable patients indicated successful delivery of microspheres to the territories previously supplied by parasitized EHAs. CONCLUSIONS: Reestablishment of intrahepatic arterial inflow to hepatic tumors by embolization of parasitized EHAs is safe and effective and results in successful delivery of yttrium-90 microspheres to tumors previously perfused by parasitized EHAs.

Consolidation of hepatic arterial inflow by embolization of variant hepatic arteries in preparation for yttrium-90 radioembolization.

PURPOSE: Before yttrium-90 ((90)Y) radioembolization administration, the authors consolidated arterial inflow by embolizing variant hepatic arteries (HAs) to make microsphere delivery simpler and safer. The present study reviews the technical and clinical success of these consolidation procedures. MATERIALS AND METHODS: Preparatory and treatment angiograms were retrospectively analyzed for 201 patients. Variant HAs were coil-embolized during preparatory angiography to simplify arterial anatomy. Collateral arterial perfusion of territories previously supplied by variant HAs was evaluated by digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m ((99m)Tc)-macroaggregated albumin (MAA) scintigraphy, and by follow-up evaluation of regional tumor response. RESULTS: A total of 47 variant HAs were embolized in 43 patients. After embolization of variant HAs, cross-perfusion into the embolized territory was depicted by DSA and by C-arm CT in 100% of patients and by (99m)Tc-MAA scintigraphy in 92.7%. Uniform progressive disease prevented evaluation in 33% of patients, but regional tumor response in patients who responded supported successful delivery of microspheres to the embolized territories in 95.5% of evaluable patients. CONCLUSIONS: Embolization of variant HAs for consolidation of hepatic supply in preparation for (90)Y radioembolization promotes treatment of affected territories via intrahepatic collateral channels.

Imaging guidance with C-arm CT: prospective evaluation of its impact on patient radiation exposure during transhepatic arterial chemoembolization.

PURPOSE: To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization. MATERIALS AND METHODS: Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured. RESULTS: The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively. CONCLUSIONS: Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.