Transarterial embolization to treat hemodynamically unstable trauma patients with splenic injuries: A retrospective multicenter observational study.

PURPOSE: We described clinical outcomes for patients with blunt splenic injuries treated with transarterial embolization (TAE) based on their hemodynamic status. MATERIALS AND METHODS: This is a retrospective two-center study of adult patients with splenic injuries who underwent emergency TAE between January 2011 and December 2022. Patients were divided into two groups; hemodynamically unstable (HDU) and hemodynamically stable (HDS) patients. HDU patients were defined as transient- or non-responders to fluid resuscitation and HDS as responders. When immediate laparotomy was not possible for HDU patients, angiography and embolization were performed. The primary outcome was the survival discharge rate. Rebleeding and splenectomy rate was also investigated. RESULTS: Of 38 patients underwent emergency TAE for splenic trauma, 17 were HDU patients and 21 were HDS patients. The survival discharge rate was 88.2 % (15/17) in the HDU- and 100 % in HDS patients (p = 0.193). Rebleeding rate was 23.5 % (4/17) in HDU- and 5.0 % (1/21) in HDS patients (p = 0.15). Splenectomy was required for one HDU patient (5.9 %) for rebleeding. CONCLUSION: The survival discharge rate of TAE for splenic trauma in HDU patients was acceptable with a low rate of splenectomy. Further comparative studies of TAE versus operative management in HDU patients are needed to prove the usefulness of TAE.

Development of a deep-learning algorithm for age estimation on CT images of the vertebral column.

PURPOSE: The accurate age estimation of cadavers is essential for their identification. However, conventional methods fail to yield adequate age estimation especially in elderly cadavers. We developed a deep learning algorithm for age estimation on CT images of the vertebral column and checked its accuracy. METHOD: For the development of our deep learning algorithm, we included 1,120 CT data of the vertebral column of 140 patients for each of 8 age decades. The deep learning model of regression analysis based on Visual Geometry Group-16 (VGG16) was improved in its estimation accuracy by bagging. To verify its accuracy, we applied our deep learning algorithm to estimate the age of 219 cadavers who had undergone postmortem CT (PMCT). The mean difference and the mean absolute error (MAE), the standard error of the estimate (SEE) between the known- and the estimated age, were calculated. Correlation analysis using the intraclass correlation coefficient (ICC) and Bland-Altman analysis were performed to assess differences between the known- and the estimated age. RESULTS: For the 219 cadavers, the mean difference between the known- and the estimated age was 0.30 years; it was 4.36 years for the MAE, and 5.48 years for the SEE. The ICC (2,1) was 0.96 (95 % confidence interval: 0.95-0.97, p < 0.001). Bland-Altman analysis showed that there were no proportional or fixed errors (p = 0.08 and 0.41). CONCLUSIONS: Our deep learning algorithm for estimating the age of 219 cadavers on CT images of the vertebral column was more accurate than conventional methods and highly useful.

Perioperative proximal splenic artery embolization in cirrhotic patients with splenomegaly.

INTRODUCTION: The purpose of this study was to determine the effect of proximal splenic artery embolization (SAE) in cirrhotic patients with splenomegaly who underwent surgical laparotomy. MATERIAL AND METHODS: This retrospective observational study included 8 cirrhotic patients with splenomegaly. They underwent proximal SAE before- (n = 6) or after (n = 2) laparotomy. Vascular plugs or coils were placed in the proximal splenic artery. The diameter of the portal vein and the splenic volume were recorded. Clinical outcome assessments included platelet counts, the model for end-stage liver disease (MELD) score, and complications. RESULTS: After embolization, the portal venous diameter was significantly smaller (pre: 13.6 ± 2.7 mm, post: 12.5 ± 2.3 mm, p = 0.023), the splenic volume was significantly decreased (pre: 463.2 ± 145.7 ml, post: 373.3 ± 108.5 ml, p = 0.008) and the platelet count was significantly higher (pre: 69.6 ± 30.8 × 103/µl, post: 86.8 ± 27.7 × 103/µl, p = 0.035). Before embolization, the median MELD score was 12; after embolization, it was 11 (p = 0.026). No patient developed post-treatment complications after embolization. CONCLUSIONS: The reduction of hypersplenism by perioperative proximal SAE may be safe and reduce the surgical risk in cirrhotic patients with splenomegaly.

Preoperative percutaneous or transvascular marking for curative resection of small liver tumours with potential for missing during hepatectomy: a study protocol for an open-label, single-arm phase II study.

INTRODUCTION: Small liver tumours are difficult to identify during hepatectomy, which prevents curative tumour excision. Preoperative marking is a standard practice for small, deep-seated tumours in other solid organs; however, its effectiveness for liver tumours has not been validated. The objective of this study is to evaluate the effectiveness of preoperative markings for curative resection of small liver tumours. METHODS AND ANALYSIS: This is an open-label, single-arm, single-centre, phase II study. Patients with liver tumours of ≤15 mm requiring hepatectomy will be enrolled and will undergo preoperative marking by placing a microcoil near the tumour using either the percutaneous or transvascular approach. The tumours, including the indwelling markers, will be excised. The primary endpoint will be the successful resection rate of liver tumours, defined as achieving a surgical margin of ≥5 mm and ≤15 mm. Secondary endpoints will include the results of preoperative marking and hepatectomy. ETHICS AND DISSEMINATION: Ethical approval for this trial was obtained from the Ethical Committee for Clinical Research of Hiroshima University, Japan. The results will be published at an academic conference or by submitting a paper to a peer-reviewed journal. TRIAL REGISTRATION NUMBER: jRCTs062220088.

Transportal scleroembolization of hepatic arterioportal fistulas in a patient with portal hypertension: A case report.

We report a rare patient with portal hypertension who presented with esophageal- and gastric varices and refractory ascites due to hepatic arterioportal fistulas. Treatment by transportal scleroembolization using ethanolamine oleate and coils were successful. Pretreatment hepatofugal flow subsequently changed to hepatopetal flow and the symptoms of portal hypertension improved. We describe our endovascular treatment option for addressing hepatic arterioportal fistulas.

Iodine maps derived from sparse-view kV-switching dual-energy CT equipped with a deep learning reconstruction for diagnosis of hepatocellular carcinoma.

Deep learning-based spectral CT imaging (DL-SCTI) is a novel type of fast kilovolt-switching dual-energy CT equipped with a cascaded deep-learning reconstruction which completes the views missing in the sinogram space and improves the image quality in the image space because it uses deep convolutional neural networks trained on fully sampled dual-energy data acquired via dual kV rotations. We investigated the clinical utility of iodine maps generated from DL-SCTI scans for assessing hepatocellular carcinoma (HCC). In the clinical study, dynamic DL-SCTI scans (tube voltage 135 and 80 kV) were acquired in 52 patients with hypervascular HCCs whose vascularity was confirmed by CT during hepatic arteriography. Virtual monochromatic 70 keV images served as the reference images. Iodine maps were reconstructed using three-material decomposition (fat, healthy liver tissue, iodine). A radiologist calculated the contrast-to-noise ratio (CNR) during the hepatic arterial phase (CNRa) and the equilibrium phase (CNRe). In the phantom study, DL-SCTI scans (tube voltage 135 and 80 kV) were acquired to assess the accuracy of iodine maps; the iodine concentration was known. The CNRa was significantly higher on the iodine maps than on 70 keV images (p < 0.01). The CNRe was significantly higher on 70 keV images than on iodine maps (p < 0.01). The estimated iodine concentration derived from DL-SCTI scans in the phantom study was highly correlated with the known iodine concentration. It was underestimated in small-diameter modules and in large-diameter modules with an iodine concentration of less than 2.0 mgI/ml. Iodine maps generated from DL-SCTI scans can improve the CNR for HCCs during hepatic arterial phase but not during equilibrium phase in comparison with virtual monochromatic 70 keV images. Also, when the lesion is small or the iodine concentration is low, iodine quantification may result in underestimation.

Understanding CT imaging findings based on the underlying pathophysiology in patients with small bowel ischemia.

Because acute small bowel ischemia has a high mortality rate, it requires rapid intervention to avoid unfavorable outcomes. Computed tomography (CT) examination is important for the diagnosis of bowel ischemia. Acute small bowel ischemia can be the result of small bowel obstruction or mesenteric ischemia, including mesenteric arterial occlusion, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. The clinical significance of each CT finding is unique and depends on the underlying pathophysiology. This review describes the definition and mechanism(s) of bowel ischemia, reviews CT findings suggesting bowel ischemia, details factors involved in the development of small bowel ischemia, and presents CT findings with respect to the different factors based on the underlying pathophysiology. Such knowledge is needed for accurate treatment decisions.

Prospective Exploratory Phase I Clinical Trial Assessing the Safety of Preoperative Marking for Small Liver Tumors.

Background Small tumors in liver cirrhosis are difficult to distinguish using intraoperative ultrasonography. In addition, preoperative chemotherapy for metastatic liver cancer may diminish tumor size, thus making tumors difficult to identify intraoperatively. To address such difficulties, we devised a method to mark liver tumors preoperatively to facilitate intraoperative identification. This study aimed to investigate the safety of a preoperative liver tumor marking method. Methodology This exploratory prospective clinical trial included patients with liver tumors measuring ≤20 mm requiring resection. Preoperative marking was performed by placing a coil for embolization of blood vessels near the tumor using either the transcatheter or percutaneous approach. The tumor was identified and resected by intraoperative ultrasonography based on the marker. The study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000028608). Results Overall, 19 patients (9 with primary liver cancer and 10 with metastatic tumors) were recruited. The transcatheter and percutaneous methods were used in 13 and 6 patients, respectively. Marking was not possible in two patients in the transcatheter group because the catheter could not be guided to the vicinity of the tumor. There were no marking-related complications. Hepatectomy was performed in all but one patient who was not fit for hepatectomy owing to the development of a metastatic liver tumor. The markers were adequately identified during hepatectomy. Additionally, there were no difficulties in the surgical procedure or postoperative complications. Conclusions Preoperative marking with embolization coils can be performed safely for intraoperative identification of liver nodules.

Hepatic venous pressure gradient after balloon-occluded retrograde transvenous obliteration and liver stiffness measurement predict the prognosis of patients with gastric varices.

BACKGROUND: Balloon-occluded retrograde transvenous obliteration (BRTO) is a treatment option for patients with gastric varices (GVs). This study aimed to clarify the clinical significance of portal hypertension estimated by the hepatic venous pressure gradient (HVPG), subsequent exacerbation of esophageal varices (EVs), and prognosis of patients who underwent BRTO for GVs. METHODS: Thirty-six patients with GVs treated with BRTO were enrolled in this study, and their HVPG was measured before (pre-HVPG) and on the day after BRTO (post-HVPG). After BRTO, patients were followed-up for a median interval of 24.5 (3-140) months. Clinical factors related to EVs exacerbation and prognosis after BRTO were retrospectively analyzed. RESULTS: Post-HVPG increased compared to pre-HVPG in 21 out of 36 patients (58%), and post-HVPG was overall significantly higher compared to pre-HVPG (P = 0.009). During the observation period, 19 patients (53%) developed EVs exacerbation, and the cumulative EVs exacerbation rates at 1, 3 and 5 years after BRTO were 27%, 67%, and 73%, respectively. Pre-HVPG was not related to EVs exacerbation, although elevation of post-HVPG to ≥ 13 mmHg (P < 0.01) and high level of serum aspartate aminotransferase (P < 0.05) were significant independent risk factors for EVs exacerbation after BRTO. Fourteen patients (38.9%) died during the observation period. An elevated value of liver stiffness measurement (LSM) of ≥ 21 kPa was a significant independent risk factor for poor prognosis after BRTO (P < 0.05). CONCLUSIONS: HVPG increases after BRTO. HVPG after BRTO has greater predictive ability for subsequent EVs exacerbation than HVPG before BRTO. LSM is a potential prognostic parameter in patients who undergo BRTO.

Efficacy and safety of chemoradiation therapy using one-shot cisplatin via hepatic arterial infusion for advanced hepatocellular carcinoma with major macrovascular invasion: a single-arm retrospective cohort study.

BACKGROUND: Patients with hepatocellular carcinoma (HCC) and macrovascular invasion (MVI) who receive systemic chemotherapy have a poor prognosis. This study aimed to determine if one-shot cisplatin (CDDP) chemotherapy via hepatic arterial infusion (HAI) combined with radiation therapy (RT) prior to systemic chemotherapy could improve the outcomes of these patients. METHODS: This study consisted of 32 HCC patients with the following eligibility criteria: (i) portal vein invasion 3/4 and/or hepatic vein invasion 2/3; (ii) received one-shot CDDP via HAI; (iii) received RT for MVI, (iv) a Child-Pugh score ≤ 7; and (v) an Eastern Clinical Oncology Group Performance Status score of 0 or 1. To determine the therapeutic effect, we collected information on patient characteristics and took contrast-enhanced computed tomography at the start of the therapy and every 2 to 4 months after the start of therapy. We evaluated the overall response of the tumor and tumor thrombosis according to modified Response Evaluation Criteria in Solid Tumors. We assessed patient data using the Mann-Whitney U and Fisher exact tests and evaluated overall survival and progression-free survival using the log-rank test. RESULTS: The overall response rate at the first evaluation performed a median of 1.4 weeks after HAI was 16% for the main intrahepatic tumor and 59% for the MVI. The best responses were the same as those of the first-time responses. The duration of median survival was 8.6 months, and progression-free survival of the main intrahepatic tumor was 3.2 months. Predictive factors for overall survival were the relative tumor volume in the liver and the first therapeutic response of MVI. There were no severe adverse events or radiation-induced hepatic complications. CONCLUSIONS: One-shot CDDP via HAI and RT were well tolerated and showed immediate and favorable control of MVI. Thus, this combination shows potential as a bridging therapy to systemic chemotherapy.

Cranio-caudal puncture with computed tomography-guided drainage of a deep pelvic abscess.

Purpose: Computed tomography (CT)-guided percutaneous drainage has been used to address pelvic abscesses because it is safe and minimally invasive. However, CT-guided drainage has the limitation that the puncture route should be on the same axial slice. A technique for puncturing in the cranio-caudal direction under CT fluoroscopy is needed. Case report: An 82-year-old man with an abscess due to rectal cancer was scheduled for CT-guided drainage to improve his general condition before radical surgery. Drainage was performed via a perineal approach to localize the drainage tract in the resection area to avoid dissemination of cancer cells. To perform a puncture in the cranio-caudal direction we controlled the needle like a joystick and advanced it under CT fluoroscopy while moving the CT gantry cranially to follow the needle tip throughout the puncture. Our unique technique yielded successful CT-guided puncture in the cranio-caudal direction. Conclusions: Our unique technique overcomes the limitations of CT-guided cranio-caudal puncture and may allow the drainage of abscesses whose treatment was heretofore difficult.

Safety margin for CT- and US-guided radiofrequency ablation after TACE of HCC in the hepatic dome.

INTRODUCTION: We evaluated the safety margin in patients with hepatocellular carcinoma (HCC) in the hepatic dome who underwent computed tomography (CT)- or ultrasound (US)-guided radiofrequency ablation (RFA). MATERIAL AND METHODS: Included in this single-center study were 46 patients with 56 HCCs in the hepatic dome undergoing RFA after transarterial chemoembolization from January 2009 to December 2016. Thirty were addressed with CT fluoroscopy and 26 with US guidance. The technical success, safety margin, and local tumor progression (LTP) were evaluated. RESULTS: Technical success rate was 100% in the CT-RFA and 84.6% in the US-RFA group (p = .04). The average safety margin was 4.8 mm in the CT-RFA and 3.0 mm in the US-RFA group (p = .01). There was no LTP among the HCCs with a safety margin >3 mm achieved in 73.3% CT-RFA and 42.3% US-RFA group tumors (p = .03). Of the US-RFA group, six required additional RFA. There was no significant inter-group difference in LTP (p = .36). CONCLUSION: CT-guided RFA was superior to US-guided RFA with respect to the technical success rate and the acquisition of an appropriate safety margin in patients with HCC in the hepatic dome.

Treatment of multiple huge liver cysts in a hybrid operating room: a case report.

BACKGROUND: Liver cysts are common, with most cases being asymptomatic. In symptomatic cases, the disease is amenable to treatment. However, huge or multiple liver cysts with vascular narrowing and associated systemic symptoms are extremely rare. Furthermore, the performance of a reliable and effective surgery in such cases remains a major problem. Here, we report a case of multiple giant liver cysts with impaired blood flow surgically treated in a hybrid operating room. CASE PRESENTATION: A 73-year-old male presented to a previous doctor with leg edema and dyspnea on exertion; computed tomography revealed that the cause complaint was right lung and heart compression and inferior vena cava (IVC) stenosis due to huge liver cysts in the caudal lobe. The patient was referred to our hospital because of disease recurrence despite percutaneous aspiration of the cyst. Multiple liver cysts were observed in addition to the drained cysts, two of which were located on both sides of the IVC and caused IVC stenosis. We performed open surgery for the liver cysts and used the hybrid operating room for intraoperative IVC angiography and measuring the hepatic vein and portal vein (PV) pressure. We performed unroofing of the hepatic cyst and cauterization of the cyst wall on the hepatic side. Angiography was performed before and after unroofing of the liver cysts, and IVC stenosis release was confirmed. IVC pressure measured at the peripheral side of the stenosis and PV pressures were continuously measured during surgery and were confirmed to have decreased during the opening of the liver cysts. The patient had a good postoperative course and was discharged on the 10th postoperative day. No recurrence was observed 6 months postoperatively. CONCLUSIONS: Cyst unroofing surgery using angiography in a hybrid operating room is a useful treatment for deep hepatic lesions in that vascular stenosis improvement can be intraoperatively confirmed. Moreover, in cases wherein the cyst compresses the vasculature, intraoperative monitoring of IVC and PV pressures can be used to prove that the liver cyst is hemodynamically involved.

Successful multimodality treatment for advanced hepatocellular carcinoma with tumor thrombosis of the main portal trunk: a case study.

The overall survival of patients with advanced hepatocellular carcinoma with tumor thrombosis of the main trunk or bilobar branches of the portal vein is extremely poor. Moreover, there is no standard treatment established for the condition. Herein, we present the case of a 65-year-old man who were treated the patient with hepatic arterial infusion chemotherapy, radiation therapy for tumor thrombosis, portal vein stent placement, lenvatinib administration, and renal venous shunt embolization. A complete response was observed according to mRECIST and the patient has been alive for 14 months since treatment initiation with no tumor recurrence.

Hepatic Arterial Infusion Chemotherapy Combined with Radiation Therapy for Advanced Hepatocellular Carcinoma with Tumor Thrombosis of the Main Trunk or Bilobar of the Portal Vein.

BACKGROUND: Overall survival of patients with advanced hepatocellular carcinoma (HCC) with Vp4 (tumor thrombosis of the main trunk or bilobar of the portal vein) is extremely poor. PURPOSE: The purpose of this study is to clarify the prognosis of hepatic arterial infusion chemotherapy (HAIC) combined with radiation therapy (RT) for advanced HCC with Vp4 and to analyze the factors that contribute to the prognosis. METHODS: In this retrospective cohort study, 51 HCC patients who were treated with HAIC and RT for portal vein tumor thrombosis and met the following criteria were enrolled: (i) with Vp4; (ii) Child-Pugh score of 5-7; (iii) Eastern Cooperative Oncology Group performance status of 0 or 1; (iv) no history of systemic therapy; and (v) from September 2004 to April 2019. RESULTS: Median overall survival and median progression-free survival were 12.1 and 4.2 months, respectively. Multivariate analysis showed >50% of relative tumor volume in the liver (HR, 3.027; p = 0.008) and extrahepatic spread with (HR, 3.773; p = 0.040) as significant and independent factors of OS. The total overall response rate (ORR) was 19.6%; ORR in main tumor was 13.7%; and ORR in Vp4 was 51.0%. None of the patients who received HAIC combined with RT for advanced HCC with Vp4 developed hepatic failure. This combination therapy of HAIC with RT was safe and well tolerated in all cases. CONCLUSION: Combination therapies of HAIC and RT might be good therapy for advanced HCC with Vp4.

Obliteration of a Portosystemic Shunt by Hybrid Interventional Radiology Using a Transmesenteric Approach Under Minilaparotomy After Liver Transplantation: A Case Report.

Hepatic encephalopathy that occurs long after liver transplantation (LT) is an uncommon condition. Here, we describe the successful case of a 65-year-old patient who underwent interventional radiology (IVR) using a transmesenteric approach under minilaparotomy for hepatic encephalopathy because of a portosystemic shunt 11 years after ABO-incompatible living donor LT with splenectomy. Enhanced computed tomography confirmed a huge portosystemic shunt and left gastric vein (LGV)-esophageal-azygos vein, which was not treated during LT. Liver stiffness measurements based on transient elastography did not show severe fibrosis in the liver graft. Since the hyperammonemia could not be managed with conventional medical treatment, balloon-occluded retrograde transvenous obliteration (BRTO) was indicated. However, it was difficult to perform because the drainage vein could not be approached from the inferior vena cava (IVC). Surgical shunt ligation was also difficult because of the history of multiple laparotomies. Although intraperitoneal adhesion was severe, the portosystemic shunt was successfully embolized with metallic coils and a plug by IVR using a transmesenteric approach under minilaparotomy. No complications occurred during the operation. His symptoms improved after the operation. The ammonia level and portal flow by ultrasound also improved. He was discharged 14 days after surgery without any complications.

A Ruptured Mediastinal Bronchial Artery Aneurysm Treated with Urgent Thoracic Endovascular Aortic Repair.

Bronchial artery aneurysms (BAA) are a rare but potentially life-threatening complications because of the massive hemothorax or hemoptysis that occurs with ruptures. A 79-year-old woman was transferred to our hospital because of the sudden onset of back pain, syncope, and subsequent hypotension. Computed tomography showed a left BAA with bilateral hemothorax and hemomediastinum. Transcatheter bronchial artery embolization failed because of the anatomical location, and she went into cardiopulmonary arrest. Cardiopulmonary resuscitation was performed with successful revival. Urgent thoracic endovascular aortic repair to cover the root of the left bronchial artery was successful, and she survived without any neurological deficits.

Usefulness of Amplatzer Vascular Plug for Preoperative Embolization Before Distal Pancreatectomy with En Bloc Celiac Axis Resection.

PURPOSE: We evaluated the usefulness of the Amplatzer vascular plug (AVP) for preoperative embolization before distal pancreatectomy with en bloc celiac axis resection (DP-CAR). MATERIALS AND METHODS: Between April 2010 and September 2017, 19 patients with locally advanced pancreatic body cancer underwent preoperative embolization of the common hepatic and the left gastric artery (CHA, LGA) with AVP or coils. We compared the embolization success rate, embolization-related complications, the time required for preoperative embolization before DP-CAR and the procedure costs in patients whose CHA was AVP- (n = 7) or coil (n = 12) embolized. RESULTS: The success rate for preoperative AVP and coil embolization was 100% and 83.3%, respectively. The median procedure time was shorter in patients whose CHA was embolized with AVP than coils; the difference was not significant (p = 0.045). The total cost was significantly lower for AVP than coil embolization (p = 0.01). CONCLUSION: The AVP is useful for the preoperative embolization of the CHA before DP-CAR.

Feasibility and Safety of CT-guided Intrathoracic and Bone Re-biopsy for Non-small Cell Lung Cancer.

AIM: This study aimed to retrospectively determine the feasibility and safety of computed tomography (CT)-guided intrathoracic and bone re-biopsy for patients with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Seventeen patients underwent CT-guided intrathoracic or bone re-biopsy for the determination of epidermal growth factor receptor (EGFR) T790M mutation and/or programmed cell death-ligand 1 (PD-L1) expression. The characteristics of each lesion, success rate of analyses, and complications were investigated. RESULTS: Specimens from 16 out of the 17 patients were adequate for evaluation of EGFR T790M mutation and/or PD-L1 expression. The mean diameter of the lesions was 40 mm, the mean procedural time was 24 minutes, and the median number of punctures was 2. There were no significant differences in lesion characteristics and success rates between CT-guided intrathoracic and bone re-biopsies. No serious complications occurred. CONCLUSION: Both CT-guided intrathoracic and bone re-biopsies for patients with NSCLC were feasible and safe.

Clinical Indication for Computed Tomography During Hepatic Arteriography (CTHA) in Addition to Dynamic CT Studies to Identify Hypervascularity of Hepatocellular Carcinoma.

PURPOSE: To identify factors benefiting from computed tomography during hepatic arteriography (CTHA) in addition to dynamic CT studies at the preoperative evaluation of the hypervascularity of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: We retrospectively divided 45 patients with HCC, who underwent both dynamic CT (dCT) and CTHA, into two groups based on the number of hypervascular HCCs identified on dCT and CTHA studies. In group A, the number of HCCs identified by dCT and CTHA was the same and additive CTHA had not been indicated. In group B, fewer HCCs were counted on dCT than on CTHA images, indicating that additive CTHA studies had been appropriate. We compared the patient characteristics, the serum alpha-fetoprotein level, and the tumor-liver contrast (TLC) of the main tumor on dCT scans of both groups. To identify factors alerting to the benefit of additional CTHA studies, we performed univariate logistic regression analysis. Statistically significant parameters were subjected to receiver operating characteristic analysis for obtaining the optimal cutoff value indicative of the benefit of CTHA. RESULTS: Univariate analysis identified only the TLC of the main tumor on dCT images as a significant factor for the benefit of CTHA images (P < 0.01). At the optimal cutoff value for the TLC of the main tumor on dCT images (15.9 Hounsfield units), the sensitivity and specificity for the benefit of CTHA were 85.0 and 92.0%, respectively. CONCLUSION: Evaluation of the TLC of the main tumor on dCT scans identifies patients in whom additive CTHA studies are beneficial.