Right Inferior Phrenic Artery Research Articles

Efficacy and safety of endovascular therapy for delayed hepatic artery post-pancreatectomy hemorrhage: development of extrahepatic collateral circulation and complications of post endovascular therapy

BackgroundEndovascular therapy (ET) for delayed hepatic artery post-pancreatectomy hemorrhage (HA-PPH) may require complete hepatic artery occlusion (HAO). Nonetheless, the development of extrahepatic collateral circulation (EHC) and the relationship between radiological factors (EHC, portal vein stenosis, and HAO) and adverse hepatic events after ET remain unclear. This study aimed to evaluate the efficacy and safety of ET for delayed PPH and examine the development of EHC.MethodsA total of 19 ET cases for delayed HA-PPH were reviewed. Hepatic adverse events, portal vein stenosis, HAO, and mortality rate after ET were evaluated. Moreover, EHC from the left gastric artery (LGA), right inferior phrenic artery (RIPA), left inferior phrenic artery (LIPA), right internal thoracic artery (RITA), left internal thoracic artery (LITA), renal artery (RA), omental artery (OA), intercostal artery (IA), and branch of superior mesenteric artery (BSMA) was assessed using angiogram and computed tomography angiography (CTA).ResultsAll cases were successfully treated using transcatheter arterial embolization (n = 17) and stent-graft placement (n = 2) without mortality. EHC from the LGA (8/19), RIPA (10/19), LIPA (4/19), and RITA (3/19) was observed on post-ET CTA. The incidence of hepatic adverse events was significant in the group with both HAO and portal vein stenosis (p < 0.001) and absence of EHC from LIPA and RITA (p < 0.05).ConclusionET for delayed HA-PPH might be effective and safe. While avoiding both HAO and portal vein stenosis is important, the development of EHCs from LIPA and RITA may prevent hepatic adverse events after ET.

Types of inferior phrenic arteries: a new point of view based on a cadaveric study.

The diaphragm is supplied by the superior and inferior phrenic arteries. This present study focusses on the latter. The inferior phrenic arteries (IPA) usually originate from the abdominal aorta. The two arteries have different origins, and knowledge of these is important when performing related surgical interventions and interventional radiological procedures. The aim of this study was to identify variations in the origin of the IPA and conduct relevant morphometric analyses. The anatomical variations in the origins of the left inferior phrenic artery (LIPA) and the right inferior phrenic artery (RIPA) were examined in 48 cadavers fixed in 10% formalin solution. A dissection of the abdominal region of the cadavers was performed according to a pre-established protocol using traditional techniques. Morphometric measurements were then taken twice by two of the researchers. In the cadavers, six types of origin were observed. In type 1, the most common type, the RIPA and LIPA originate from the abdominal aorta (AA) (14 = 29.12%). In type 2, the RIPA and the LIPA originate from the coeliac trunk (CT) (12 = 24.96%). In type 3, the RIPA and the LIPA originate from the left gastric artery, with no CT observed (3 = 6.24%). Type 4 has two subtypes: 4A, in which the LIPA originates from the AA and the RIPA originates from the CT (9 = 18.72%) and 4B, in which the RIPA originates from the AA and the LIPA originates from the CT (6 = 12.48%). In type 5, the LIPA originates from the AA and the RIPA originates from the AA (1 = 2.08%). Type 6 is characterised by the RIPA and LIPA forming a common trunk originating from the CT (3 = 6.24%). Our findings suggest the presence of six different types of LIPA and RIPA origin. The most common form is type 1, characterised by an IPA originating from the abdominal aorta, while the second most common is type 2, in which the IPA originates from the AA by a common trunk. The diversity of other types of origin is associated with the occurrence of coeliac trunk variation (type 3). No significant differences in RIPA diameter could be found, whereas LIPA diameter could vary significantly. No significant differences in RIPA and the LIPA diameter could be found according to sex.

Hypertrophied Right Inferior Phrenic Artery in Cirrhotic Patients without Hepatocellular Carcinoma: An Interesting Observation on 256 Slice Multidetector Computed Tomography

Abstract Aim To evaluate whether right inferior phrenic artery (RIPA) is a source of extrahepatic arterial supply to the liver in cirrhotic patients without hepatocellular carcinoma (HCC) using 256 slice computed tomography (CT). Materials and Methods Institutional review board approval was obtained for this retrospective study. A total of 262 consecutive cirrhotic patients (male:female–172:90; mean age 56.45 ± 12.96 years) without HCC and hepatic vascular invasion, and who underwent technically successful multiphase CT, were included in the study. Additionally, 280 noncirrhotic patients (male:female–169:111; mean age 54.56 ± 14.21 years) who underwent abdominal multiphase CT scans for indications other than liver disease and did not have focal liver lesions or hepatic vascular disease were included as a control group. The RIPA and left inferior phrenic artery (LIPA) diameters were measured at the level of the ascending segment of IPA located anterior to the diaphragmatic crus. The relationship between RIPA diameters and Child–Pugh score was assessed. Results The cirrhotic patient group and control group were matched for age (p = 0.11) and gender (p = 0.20). The mean diameter of RIPA in the cirrhotic group (1.93 ± 0.4 mm) was significantly higher than in the control group (1.50 ± 0.5 mm), p &lt; 0.001. The mean diameter of LIPA in the cirrhotic group (1.34 ± 0.5 mm) was not significantly higher than in the control group (1.30 ± 0.5 mm), p = 0.32. We found a statistically linear and moderate degree relationship between RIPA diameter values and Child–Pugh scores (p = 0.002, r = 0.593). Conclusion RIPA is hypertrophied in patients with cirrhosis without HCC. It may be an important contributor to the blood flow to the liver in cirrhotic patients even without HCC, especially with portal hypertension.

Variations in the Origins of Inferior Phrenic Arteries—An Evaluation with 256 Slice Multidetector Computed Tomography

Abstract Aim To evaluate the frequency and pattern of variations in the origins of right inferior phrenic artery (RIPA) and left inferior phrenic artery (LIPA) on 256 slice multidetector computed tomography (MDCT). Materials and Methods MDCT abdominal images of 600 patients (male: 344, female: 256; mean age 56.45 ± 12.96 years) who underwent technically successful multiphase computed tomography were assessed for IPA variations with emphasis on their origins and results analyzed. Results Both IPA origins were documented in all patients. Both RIPA and LIPA originated from the common trunk in 128 (21.3%) patients. IPAs with common trunk most commonly originated from the aorta (68, 11.3%). Without common trunk RIPA most commonly originated from the aorta (225, 37.5%) and LIPA from the celiac artery (278, 46.3%). The least frequently detected IPA variations were RIPA originating from the common hepatic artery (1, 0.2%), superior mesenteric artery (1, 0.2%), and common truncus originating from left renal artery (1, 0.2%). Conclusion MDCT demonstrates the IPA origins very well, enabling planning of interventional procedures related to IPA. Without common trunk RIPA most commonly originates from aorta and LIPA from the celiac artery. IPAs with common trunk most commonly originate from aorta.

Blood supply to the caudate lobe of the liver from the right inferior phrenic artery: observation by cone-beam computed tomography during arteriography.

To retrospectively evaluate blood supply to the caudate lobe of the liver from the right inferior phrenic artery (RIPA) using cone-beam computed tomography during arteriography (CBCTA-RIPA). CBCTA-RIPA examinations during transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) were collected from 2448 procedures in 787 patients. The exclusion criteria were (1) major artifacts, (2) TACE of hepatic arterial branches before performing CBCTA-RIPA, and (3) repeated CBCTA-RIPA studies in the same patient. Blood supply to three subsegments, the Spiegel lobe (SP), paracaval, and caudate process, was evaluated on CBCTA-RIPA images. The origins and routes of branches supplying the caudate lobe were also evaluated by three-dimensional vessel-tracking software. Forty-seven CBCTA-RIPA examinations in 47 patients (38 with a history of TACE [repeated TACE group] and nine without it [initial TACE group]) were eligible, including five who had previously undergone hepatectomy. Seven had caudate lobe HCCs. Blood supply to the caudate lobe was demonstrated in 21 (44.7%) patients: in 50% (19/38) and 22.2% (2/9) of the repeated and initial TACE groups, respectively. The caudate arteries had previously been embolized in eight patients, the RIPA branch in three, and both in one. Forty-one proximal branches mainly supplied the dorsal part of the SP. All branches but five reached there through the inferior vena cava (IVC) ligament. The RIPA supplied eight of nine caudate lobe HCCs, totally (n = 7) or partially (n = 1). The proximal RIPA branches mainly supply the dorsal SP through the IVC ligament, especially in the repeated TACE group.

Right inferior phrenic artery; Don't miss on MDCT before chemoembolization of hepatic dome HCC

BackgroundTransarterial chemoembolization (TACE) is considered a standard local-regional treatment for intermediate-stage hepatocellular carcinoma (HCC) and the most common bridging therapy. HCC typically receives its blood supply from the hepatic artery; however, it can recruit a parasitic supply from extrahepatic collateral arteries. The right inferior phrenic artery (RIPA) is considered the most common extrahepatic collateral pathway supplying HCC and so interfere with the therapeutic efficacy of TACE resulting in treatment failure and poor outcome. Imaging by MDCT with angiography has an essential role in depicting the presence or absence of an EHC arterial supply during the pre-TACE evaluation. We analyzed MDCT studies with CT angiography of patients with hepatic dome HCC retrospectively to confirm the diagnosis of HCC and to assess its blood supply. All patients were subjected to a proper assessment by history, clinical examination, as well as routine laboratory investigationsResultsOur study includes 58 cases with hepatic dome HCC. On CT angiography, the extrahepatic collateral from the RIPA supplying hepatic dome HCC was detected in about 33 out of 58 cases (56.9%). The RIPA arose directly from the aorta in 30 cases (90.9%) with only three cases (9.1%) from the celiac trunk. All cases were managed with TACE with about 25 out of 33 cases (75.8%) with extrahepatic RIPA were undergone concomitant embolisation of both RIPA and hepatic artery during TACE procedure.ConclusionMDCT assesses well the HCC arterial supply which is fundamental for planning subsequent cannulation and embolization of extrahepatic RIPA supply to hepatic dome HCC.

Right inferior phrenic artery pseudoaneurysm after a laparoscopic gastrectomy: a case report

BackgroundRuptured pseudoaneurysms are a rare complication of gastrectomy, but when they do develop, they are often fatal. We presented herein the first report of a case of pseudoaneurysm arising from the right inferior phrenic artery (RIPA) after a laparoscopic gastrectomy.Case presentationA 61-year-old male patient underwent a laparoscopic distal gastrectomy and D1+ lymph node dissection with Roux-en-Y reconstruction for early gastric cancer. He was discharged on postoperative day (POD) 9 without any complications, such as anastomotic or pancreatic leakage. On POD 19, he was referred to the emergency room for upper abdominal pain. Enhanced abdominal computed tomography revealed a 60 × 70 mm hematoma, indicating intra-abdominal bleeding and a 10-mm pseudoaneurysm in the RIPA. Selective digital subtraction angiography confirmed the presence of a pseudoaneurysm in the RIPA, which was embolized using multiple microcoils. Thereafter, no clinical signs were observed, and the patient was discharged from the hospital 15 days after angiography without any recurrence of bleeding. We hypothesized that the cause of the pseudoaneurysm was mechanical vascular injury due to the thermal spread of the ultrasonically activated devices (USADs) during lymphatic node dissection.ConclusionGiven the thermal spread of USADs, safe and appropriate lymph node dissection based on precise anatomical knowledge is crucial to preventing postoperative pseudoaneurysms.

Yttrium-90 Radioembolization of the Right Inferior Phrenic Artery in 20 Patients with Hepatocellular Carcinoma

PurposeTo address the feasibility of infusion of yttrium-90 (90Y) glass microspheres directly through the right inferior phrenic artery (RIPA). Materials and MethodsFrom November 2015 to May 2017, 20 patients underwent 90Y radioembolization through the RIPA. When the systemic-to-pulmonary shunt was demonstrated on C-arm computed tomography (CT) of the RIPA, prophylactic embolization by polyvinyl alcohol (PVA) particles was performed prior to infusion of 90Y glass microspheres. Follow-up CT scans were retrospectively reviewed for pulmonary complications. Tumor response was determined by the modified Response Evaluation Criteria in Solid Tumors. ResultsNine (45%) patients had systemic-to-pulmonary shunts on C-arm CT images of the RIPA. The feeder of the systemic-to-pulmonary shunt was the azygoesophageal branch (n = 7) and the anterior branch (n = 2). The mean activity of 90Y glass microspheres infused into the RIPA was 0.49 GBq (range, 0.19–1.55 GBq). No patient had symptomatic radiation pneumonitis or cutaneous complications during follow-up. Seven patients had focal atelectasis (n = 5), focal ground-glass opacity (n = 2), and/or a small amount of pleural effusion (n = 2) on follow-up image. Best tumor response fed by the RIPA was complete response (n = 4), partial response (n = 9), stable disease (n = 2), progressive disease (n = 4), and unevaluable (n = 1). ConclusionThe administration of 90Y glass microspheres through the RIPA may be safe after embolization of a systemic-to-pulmonary shunt identified on C-arm CT.

Abstract No. 535 90Y radioembolization of the right inferior phrenic artery in 20 patients with hepatocellular carcinoma

To address the feasibility and safety of infusion of 90Y glass microspheres directly through the right inferior phrenic artery (RIPA). From November 2015 to May 2017, 20 patients underwent 90Y radioembolization through the RIPA. When the systemic-to-pulmonary shunt was demonstrated on C-arm computed tomography (CT) of the RIPA, prophylactic embolization by polyvinyl alcohol (PVA) particles was performed prior to infusion of 90Y glass microspheres. Follow-up medical records and CT scan were retrospectively reviewed for tumor response and possible complications. Nine (45%) patients had systemic-to-pulmonary shunts on C-arm CT images of the RIPA. The feeder of systemic-to-pulmonary shunt was the azygoesophageal branch (n = 7) and the anterior branch (n = 2). The mean activity of 90Y glass microspheres infused into the RIPA was 0.49 GBq (range, 0.19-1.55 GBq). No patient had radiation pneumonitis or cutaneous complications during follow-up. Seven patients had focal atelectasis (n = 5), focal ground glass opacity (n = 2), and/or small amount of pleural effusion (n = 2) on follow-up image. Tumor response fed by the RIPA was complete response (n = 5), partial response (n = 8), stable disease (n = 4), and progressive disease (n = 3). The administration of 90Y glass microspheres through the RIPA is safe after embolization of a systemic-to-pulmonary shunt identified on C-arm CT.

Common and separate origins of the left and right inferior phrenic artery with a review of the literature.

In a 94-year-old male cadaver, upon which routine dissection was being conducted, a rare variation was found in the gastrophrenic trunk (GPT), the common trunk of the left gastric artery (LGA), right inferior phrenic artery (RIPA), and left inferior phrenic artery (LIPA); the GPT arises from the abdominal aorta. A hepatosplenic trunk accompanied the variation. In this variation, the RIPA first branched from the GPT and then to the LIPA and LGA. Variations in the common trunk of the LIPA and RIPA in the GPT are common, but to our knowledge, a variation (separate inferior phrenic artery in the GPT) similar to our findings has not been previously reported. We discuss the incidence and developmental and clinical significance of this variation with a detailed review of the literature. Knowledge of such a case has important clinical significance for invasive and non-invasive arterial procedures. Therefore, different variations concerning the LGA and inferior phrenic artery should be considered during surgical and non-surgical evaluations.

Variations in the Origin of Inferior Phrenic Arteries and Their Relationship to Celiac Axis Variations on CT Angiography.

ObjectiveKnowing the origin of the inferior phrenic artery (IPA) is important prior to surgical interventions and interventional radiological procedures related to IPA. We aimed to identify variations in the origin of IPA and to investigate the relationship between the origin of IPA and celiac axis variations using computed tomography angiography (CTA).Materials and MethodsThe CTA images of 1000 patients (737 male and 263 female, the mean age 60, range 18–94 years) were reviewed in an analysis of IPA and celiac axis variations. The origin of IPA was divided into two groups, those originating as a common trunk and those originating independently without a truncus. The relationship between the origin of IPA and celiac axis variation was analyzed using Pearson's chi-square test.ResultsBoth IPAs originated from a common trunk in 295 (29.5%) patients. From which the majority of the common trunk originated from the aorta. Contrastingly, the inferior phrenic arteries originated from different origins in 705 (70.5%) patients. The majority of the right inferior phrenic artery (RIPA) and the left inferior phrenic artery (LIPA) originated independently from the celiac axis. Variation in the celiac axis were detected in 110 (11%) patients. The origin of IPA was found to be significantly different in the presence of celiac axis variation.ConclusionThe majority of IPA originated from the aorta in patients with a common IPA trunk, while the majority of RIPA and LIPA originating from the celiac axis in patients without a common IPA trunk. Thus, the origin of IPA may widely differ in the presence of celiac axis variation.

Imaging features of factors related to blood supply from right inferior hepatic artery branches in hepatocellular carcinoma

To analyze the angiographic features and factors related to the blood supply from right inferior phrenic artery (RIPA) branches in hepatocellular carcinoma (HCC). Angiography images of blood supply from RIPA branches and clinical data from patients with HCC who had undergone tmnscatheter arterial chemoembolization in our hospital between 2009 and 2013 were collected for retrospective analysis. Angiographic features of the RIPA branches were assessed for correlation between treatment number, growth pattern, size, tumor location, and rates of blood supplying RIPA branches. Statistical analyses were carried out using chi-square test, t-test, Fisher's exact test and rank sum test. The 140 patients included in the analysis were grouped according to primary HCC (n=63; group A) and recurrent HCC (n=77; group B) and no statistically significant differences were found between the two groups for incidence of each nutrient branch or total number of nutrient branches. In group A, tumor size was associated with number of nutrient branches (P=0.047). There were 32 cases with HCC lesions in the bare area of the liver, and among those 26 of the cases were supplied by the posterior branch of RIPA. Each branch of RIPA showed greater firequency for particular blood supply areas; the anterior branch (n=55) and lateral branch (n=98) fed tumor lesions in segments 7 and 8, the posterior branch (n=98) fed tumor lesions in segments 6 and 7, and the supra-renal branch (n=10) fed tumor lesions in segment 6. The diaphragmatic branch always fed HCC partly located in segments 4 and 8 (n=17). Unique features were present on the digitally subtracted angiography (DSA) image for each nutrient branch and may be useful for distinguishing in clinical examination. Cases of primary HCC and recurrent HCC are not distinguishable by incidence of each nutrient branch or total numbers of the nutrient branches. However, tumor size is related to the number of RIPA nutrient branches, and each RIPA nutrient branch shows a dominant preference for certain blood supply areas, with unique features on DSA.

Chemoembolization of extrahepatic collateral arteries for treatment of hepatocellular carcinoma in the caudate lobe of the liver.

This study was designed to evaluate the efficacy and safety in performing chemoembolization of extrahepatic collateral arteries (EHC) for hepatocellular carcinoma (HCC) located in the caudate lobe. Between January 2006 and November 2013, chemoembolization via EHC was performed in 35 patients with 35 caudate HCCs. Preprocedural and follow-up CT or MR scans, angiographic images, and medical records were reviewed retrospectively in consensus. Chi-square analysis was used to evaluate the relationship between tumor characteristics and type of EHC and that between tumor response and the characteristics of the tumor and chemoembolization. In 31 (88.6 %) patients, EHCs supplying the caudate HCC originated from the right inferior phrenic artery (RIPA). The remaining four HCCs were supplied by the gastroduodenal artery, dorsal pancreatic artery, and right and left gastric arteries. Superselective catheterization of tumor-feeding vessels from the EHC was achieved in 27 patients (77.1 %). There were no major complications. Individual tumor response supplied by the EHC at follow-up contrast-enhanced CT were as follows: complete response (n = 18), partial response (n = 9), stable disease (n = 3), and progressive disease (n = 3). Non-RIPA EHCs were significantly more common in patients who had previously received chemoembolization via the RIPA (50 %) than those who had not (6.5 %; P = 0.01). There was no significant predictive factor associated with tumor response. HCC in the caudate lobe can be supplied by several EHCs. Chemoembolization via these arteries can be performed safely and effectively.

Common stem origin of left gastric, right and left inferior phrenic arteries, in association with a hepatosplenomesenteric trunk, independently arising from the abdominal aorta: Case report using MDCT angiography

We describe in this paper a rare case of a 45-year-old male with a common stem origin of the left gastric artery (LGA), right inferior phrenic artery (RIPA), and left inferior phrenic artery (LIPA), in association with the presence of a hepatosplenomesenteric trunk (HSMT) arising from the abdominal aorta (AA), as revealed by routine multidetector computed tomography (MDCT) angiography. The common stem origin of the LGA, RIPA, and LIPA had an endoluminal diameter of 3.3 mm, the LGA of 2.8 mm. The endoluminal diameter of the RIPA and LIPA was at the origin of approximately 1 mm, complicating selective chemoembolization of the liver parenchyma.

Arterial blood supply to the caudate lobe of the liver from the proximal branches of the right inferior phrenic artery in patients with recurrent hepatocellular carcinoma after chemoembolization

To evaluate the arterial blood supply to the caudate lobe of the liver from the proximal branches of the right inferior phrenic artery (RIPA) in patients with recurrent hepatocellular carcinoma after transcatheter arterial chemoembolization (TACE). Thirteen patients, including 10 who had a history of TACE of the caudate artery (A1), underwent TACE of the proximal RIPA branches. Iodized oil distribution was evaluated by computed tomography (CT) 1-week after TACE. Angiographic findings were also evaluated. Previously embolized A1 was occluded (n = 15) or attenuated (n = 2). In one of three patients without A1 TACE, A1 was also attenuated. TACE was performed at the first branch of the proximal RIPA (n = 8), the first branch of the anterior branch (n = 6), and the first branch of the posterior branch (n = 1), respectively. Iodized oil was mainly distributed into the dorsal part of the Siegel lobe (SP) (n = 10), the caudate process (n = 1), and both (n = 2). In three of seven patients who had undergone serial RIPA angiography, RIPA parasitization to SP was suspected before A1 TACE. The proximal RIPA branches mainly supply the SP when A1 is attenuated.

Internal Thoracic Artery as an Abnormal Collateral Source to the Visceral Organs in Coronary Surgery

l I l t f T W l e p l e v t a i t t A 78-year-old man was admitted to our hospital with angina pectoris and multiple coronary risk factors. oronary angiography revealed severe coronary lesions nd an angiography of the left internal thoracic artery LITA) showed collateral arteries leading from the LITA o the visceral arteries (Fig 1). Evaluation of these collatrals using multi-slice computed tomography revealed otal occlusion of the celiac trunk (CT), as well as severe tenosis of the superior mesenteric artery (SMA), and the nferior mesenteric artery (IMA). Abnormal collateral irculation from the LITA to the CT through the muscuophrenic artery (MPA), left inferior phrenic artery LIPA), and left gastric artery (LGA) had developed along ith other collaterals leading from the right internal horacic artery (RITA) to the hepatic artery through the PA and the right inferior phrenic artery (RIPA) (Fig 2). ecause the symptoms of abdominal angina were absent, e performed isolated off-pump coronary artery bypass urgery with a radial graft to the left anterior descending oronary artery and saphenous vein grafts to the left ircumflex artery and right coronary artery. Two days

Abstract No. 196: Transcatheter arterial chemoembolization for hepatocellular carcinoma fed by the right inferior phrenic artery: Clinical outcomes and rare pulmonary complications

Abstract No. 196: Transcatheter arterial chemoembolization for hepatocellular carcinoma fed by the right inferior phrenic artery: Clinical outcomes and rare pulmonary complications

Does the right inferior phrenic artery has a supplying role in liver cirrhosis without HCC?: 64-slice CT evaluation

To investigate whether the right inferior phrenic artery (RIPA) has a role in supplying the liver in cirrhotic patients without hepatocellular carcinoma (HCC) using 64-slice computed tomography (CT). Fifty-eight consecutive cirrhotic patients were categorized into two groups in regard to the absence (group 1, n=33) or presence of portal vein thrombosis (group 2, n=25). In addition, 35 patients without liver disease were included as a control group (group 0). The diameters of the RIPA and left inferior phrenic artery (LIPA) were measured in the ascending portion of these vessels using arterial-phase CT images. The discrepancy between the diameters of the RIPA and LIPA were calculated. The diameters of the RIPA and LIPA and the discrepancy between the diameters of the RIPA and LIPA were then compared. The characteristics of all RIPA and LIPA were visualized. The diameter of the LIPA among the three groups was not significantly different (P = 0.363). The mean diameters of the LIPA were 1.8±0.19, 1.8±0.22, and 1.7±0.38 mm for groups 0, 1, and 2, respectively. The diameter of the RIPA was significantly greater (2.1±0.54 mm) in groups 1 and 2 (1.9±0.19 mm) than in group 0 (1.8±0.18 mm). There was significantly difference between groups 0 and 2 (P = 0.003), and groups 1 and 2 (P = 0.01) with regard to the discrepancy of the diameters of RIPA and LIPA. The RIPA may contribute to the blood supply of the liver in cirrhotic patients, especially those with portal venous thrombosis.

The Right Inferior Phrenic Artery: Origin and Proximal Anatomy on Digital Subtraction Angiography and Thin-section Helical Computed Tomography

To investigate the origin sites of the right inferior phrenic artery (RIPA) and its proximal anatomy with use of digital subtraction angiography (DSA) and thin-section computed tomography (CT). Among 2,593 patients, selective RIPA arteriography was attempted in 591 (507 men; mean age, 54 years) who underwent chemoembolization and thin-section liver CT. CT and DSA images were reviewed. The origin sites of the RIPA and its proximal segment were analyzed on DSA and CT in 580 patients after 11 were excluded because of a completely occluded or unidentifiable RIPA. The RIPA originated directly from the aorta in 336 patients (57.9%) and from the major visceral aortic branches in 244 (42.1%). In RIPAs of aortic origin, the most common level was the supraceliac aorta (n = 119; 35.4%), and the mean angular orientation slightly deviated to the left side of the aorta (12.1 degrees ). As the level of origin became lower (from "juxtaceliac" to suprarenal), there were two groups in whom the RIPAs arose around an oblique path from the supraceliac aorta to the right renal artery (n = 199; 59.2%) or left renal artery (n = 18; 5.4%). When the RIPA origin was draped by the diaphragm (n = 197; 58.6%), its proximal segment showed a downward and/or leftward impression or an acute rightward turn depending on its level of origin and angular orientation. Unusually, three RIPAs under the right hemidiaphragm exhibited a transdiaphragmatic course. RIPAs had diverse proximal anatomy relative to their origin level and overhanging diaphragmatic crus, which could be evaluated with thin-section helical CT.

Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma: Prospective Assessment of the Right Inferior Phrenic Artery with C-arm CT

To assess the usefulness of C-arm computed tomography (CT) of the right inferior phrenic artery (RIPA) in transcatheter arterial chemoembolization of patients with hepatocellular carcinoma (HCC). From December 2007 to April 2008, C-arm CT of the RIPA was prospectively performed in 32 patients with HCC. Two interventional radiologists who performed C-arm CT assessed the additional information provided with C-arm CT as grade 1 (no additional information), grade 2 (added information without an effect on the treatment plan), or grade 3 (added information with an effect on the treatment plan). Tumor feeders and feeders of a systemic-to-pulmonary shunt were recorded. The information provided by C-arm CT was classified as grade 1 for nine of the 32 patients (28%), grade 2 for 20 patients (63%), and grade 3 for three patients (9%). The most common additional information from C-arm CT scans of the RIPA was the differentiation between the tumor and the systemic-to-pulmonary shunt. A systemic-to-pulmonary shunt from the RIPA was observed in 22 patients (69%), and the most common feeder of a systemic-to-pulmonary shunt was the azygoesophageal branch. C-arm CT of the RIPA provides additional imaging information for the differentiation of a tumor from a nontumorous condition during chemoembolization for HCC with a suspected blood supply from an RIPA.