The vascular anatomy of the ligaments of the liver: gross anatomy, imaging and clinical applications.

The vessels that communicate between the liver and adjacent structures require bridges between them. The bridges comprise the ligaments of the liver as follows: the falciform ligament, right and left coronary ligaments, lesser omentum including the hepatogastric ligament and hepatoduodenal ligament. Each ligament has specific communications between the intrahepatic and extrahapetic vessels. The venous communications called as the portosystemic shunt would become apparent in patients with portal hypertension, intrahepatic portal vein thrombosis and superior vena cava syndrome. The location of the venous communication is related to the pseudolesion or focal enhancement of the liver demonstrated on the CT scan. The arterial communications called collateral vascularization would become apparent in patients with hepatic artery occlusion, especially post-transhepatic arterial embolization, or in patients with the hepatic tumour abutting diaphragm. The knowledge of these collateral arteries is necessary to accomplish the effective transarterial embolization for the hepatic tumours. We reviewed the vessels in these ligaments using contrast-enhanced CT scans and angiography and discussed the clinical applications. Cadaver dissection photos were included as supplementary images for readers to recognize the actual spatial anatomy of the vessel in each ligament.

Spatial anatomy of the round ligament, gallbladder, and intrahepatic vessels in patients with right-sided round ligament of the liver.

PURPOSE: To analyze the vascular structure of the liver in patients with a right-sided round ligament. METHODS: We reviewed 16 patients with a right-sided round ligament and 3 polysplenia and situs inversus patients with a left-sided round ligament who underwent multidetector row CT with contrast media. The patient population consisted of 13 men and 6 women (mean 62 years). We analyzed the axial and volume-rendered images for the location of the round ligament, gallbladder, portal veins, hepatic veins, and hepatic artery. The following imaging findings for the patients with polysplenia and situs inversus were horizontally reversed. RESULTS: The prevalence of a right-sided round ligament with and without polysplenia was 75 and 0.11 %, respectively. The gallbladder was located to the right, below, and left of the round ligament in 27.7, 38.8 and 33.3 %, respectively. Independent branching of the right posterior portal vein was noted in 57.8 %. PV4 was difficult to identify in 36.8 %. The middle hepatic vein was located to the left of the round ligament. Two branching patterns for the lateral and medial branches of the right anterior hepatic artery were noted: the common (44.4 %) and separated types (55.5 %). Both of the right anterior hepatic artery and portal vein ramified into two segments; the lateral segment with many branches and the medial segment with a few branches. CONCLUSIONS: The right-sided round ligament divided the right anterior section into the lateral and medial segments based on the portal vein and hepatic artery anatomy.

Protective effect against repeat adverse reactions to iodinated contrast medium: Premedication vs. changing the contrast medium.

OBJECTIVES: The purpose of this study was to assess the protective effect of premedication and changing contrast media (CM) against repeat adverse reactions (ARs) to iodinated CM. METHODS: Between January 2006 and September 2014, 771 cases with previous ARs to CM were administered CM. The same CM that had caused ARs previously was administered to 491 cases (220 without premedication [defined as the control group], and 271 with premedication [the premedication alone group]). A different CM from the previous CM was given to 280 cases (58 without premedication [the changing CM alone group], and 222 with premedication [the premedication and changing CM group]). RESULTS: The control group had 61 repeat ARs (27.7%). The premedication alone group had 47 ARs (17.3%, p<0.01). The changing CM alone group had 3 ARs (5.2%, p<0.001). Three ARs (7.9%) were observed in 38 cases changing from one to another low-osmolar nonionic CM. Twenty cases with previous ARs to the high-osmolar CM and to the low-osmolar ionic CM showed no ARs. The premedication and changing CM group had 6 ARs (2.7%, p<0.001). CONCLUSION: Premedication prior to contrast for patients with previous ARs may be protective, however, changing CM was more effective. KEY POINTS: • In patients with previous adverse reactions, changing contrast media is recommended. • Premedication is unnecessary against previous reactions to high-osmolar or ionic CM. • Changing from one to another low-osmolar non-ionic CM may be effective.

An analysis of initial and follow-up CT findings in intramural hematoma, aortic double-lumen dissection, and mixed type lesions.

BACKGROUND: Although the clinical presentation of intramural hematoma (IMH) and aortic double-lumen dissection (AD) is similar, the imaging results and subsequent clinical course of the two lesions differ. PURPOSE: To compare the clinical and radiological findings of IMH, AD, and mixed type lesions. MATERIAL AND METHODS: Forty-two patients with IMH, 38 with AD, and 10 with mixed type lesions were imaged with post-contrast-enhanced CT. The most proximal ulcer-like lesions and entry tears and the distal ends of the IMH and AD were evaluated. The interval change of the intramural hematoma, ulcer-like lesion, and false lumen was observed. The pathological findings of the aorta were evaluated in 15 patients. RESULTS: The most proximal ulcer-like lesion and entry tear were located in the arch to the descending aorta in 27 (64.2%) of the 42 patients with IMH and in 24 (63.1%) of the 38 patients with AD. The distal extension was located at the iliac arteries in six (14.3%) patients with IMH and in 31 (81.6%) patients with AD (P < 0.001). The intramural hematomas regressed in 29 (93.5%) of 31 patients, and the ulcer-like lesion progressed in 14 (70%) of 20 patients with IMH. The clinical features of the mixed type lesions resembled those of AD, rather than IMH. The intramural hematoma or dissection was observed within the outer media in all lesion types on histopathology. CONCLUSION: There is a distinct difference between IMH and AD in distal extension; however, the locations of the lesions are pathologically the same in the media of the aorta.

Spatial relationship between the hepatic artery and portal vein based on the fusion image of CT angiography and CT arterial portography: the left hemiliver.

OBJECTIVE: The objective of our study was to clarify the hepatic artery anatomy of the left hemiliver using the fusion image of CT angiography (CTA) and CT arterial portography. MATERIALS AND METHODS: CTA and CT arterial portography were performed on a 64-MDCT scanner in 144 patients. All images were transferred to a workstation for 3D analysis using the multiimage fusion mode. We classified the left hepatic artery (LHA) and middle hepatic artery (MHA) as type L when only the LHA was present, type MB when a medial branch from the LHA was present, type LM when both the LHA and MHA were present, and type M when only the MHA was present. The hepatic artery was classified into infraportal and supraportal groups on the basis of its relationship with the laterosuperior branch of the left portal vein. We also classified the branching pattern of the arteries to each segment. Pattern 1 was defined as when the LHA divided into the laterosuperior segment artery (A2), which then divided into the lateroinferior segment artery (A3) and medial segment artery (A4). Pattern 2 was defined as when the LHA divided into A3, which then divided into A2 and A4. Pattern 3 was defined as when the LHA divided into A4, which then divided into A2 and A3. Pattern 4 was defined as when the LHA divided into A2, A3, and A4 simultaneously. RESULTS: The prevalence of each type was as follows: type L (n = 37, 25.7%), type MB (n = 44, 30.6%), type LM (n = 53, 36.8%), and type M (n = 6, 4.2%). The number of cases classified as infraportal was 54 (37.5%) and supraportal, 73 (50.7%). The cases classified by branching pattern were as follows: pattern 1, 26 cases (18.0%); pattern 2, eight (5.6%); pattern 3, 93 (64.5%); and pattern 4, 13 (9.0 %). CONCLUSION: Three-dimensional fusion images based on CTA and CT arterial portography can show the various anatomic patterns of the left hemiliver hepatic artery in relation to the left portal vein.

Spatial relationship between intrahepatic artery and portal vein based on the fusion image of CT-arterial portography (CTAP) and CT-angiography (CTA): new classification for hepatic artery at hepatic hilum and the segmentation of right anterior section of the liver.

PURPOSE: To clarify the variations of the intrahepatic artery and portal vein and to verify the proper segmentation for the right anterior section of the liver. MATERIALS AND METHODS: CT during arterial portography and CT angiography were performed on 64-slice multi detector row CT in 147 patients. All images were transferred to a workstation for analysis using multi-image-fusion mode. We investigated the spatial relationship between hepatic artery and portal vein in the right hemiliver and the segmentation of the right anterior hepatic artery and portal vein. RESULTS: The spatial anatomy of right hepatic arteries and portal vein was (1) anterior and posterior hepatic artery run superior and inferior to anterior portal vein, respectively (47.6%), (2) one anterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (15%), (3) anterior and posterior hepatic arteries run superior to anterior portal vein (11.6%), (4) anterior and posterior hepatic arteries run inferior to anterior portal vein (7.5%), and (5) one posterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (6.8%). The combined anatomy of right anterior artery and portal vein with regard to segmentation was classified as (1) dorso-ventral (26.5%), (2) dorso-ventral and inferior (10.9%), (3) multiple (18.4%), and (4) superior and inferior segments (1.4%). CONCLUSION: There are various types of spatial anatomy of intrahepatic artery and portal vein. The hepatic arteries as well as portal veins of right anterior section of the liver could be divided into dorsal and ventral, not superior and inferior.

Anatomy of right superior septal artery demonstrated on the coronary CT scan.

BACKGROUND: A coronary CT scan allows for non-invasive visualization of the anatomy of a coronary artery in three dimensions compared to the two dimensions afforded by conventional angiography. The septal artery, the main blood source of the interventricular septum, is usually derived from the left anterior descending artery; however, it is occasionally derived from the right coronary artery. PURPOSE: To analyze the prevalence, origin, diameter, and length of the right superior septal artery (RSSA) demonstrated on a coronary CT scan. MATERIAL AND METHODS: The right superior septal artery was retrospectively reviewed on the reconstructed axial scan images (0.5-mm thickness, 0.25-mm interval) in 1290 consecutive patients who underwent coronary CT scans. All patients were scanned on a 320-row CT scanner. The images were transferred to a workstation to trace the vessel to analyze the origin, diameter, and length. We also compared the length of the RSSA between patients with and without coronary artery stenosis. RESULTS: The RSSA was identified in 51 (3.9%) of 1290 patients. The origin was the proximal portion of the right coronary artery (n = 40) or the right sinus of Valsalva (n = 11). The artery co-existed with the conus artery in 15 (29%) of 51 patients. The length was 16-62 mm (mean 31.2 mm ± 10.5), and the diameter was 0.8-2.0 mm (mean 1.3 mm ± 0.2). Longer RSSAs tended to be demonstrated in the patients with coronary artery stenosis rather than with normal coronary arteries (P < 0.05). CONCLUSION: The right superior septal artery and its anatomical variant could be analyzed with a coronary CT scan. The ability to demonstrate this artery on the coronary CT scan was the same as with coronary angiography. The recognition of this vessel is useful for physicians managing with the diagnosis and treatment of the coronary artery disease.

Air embolism and needle track implantation complicating CT-guided percutaneous thoracic biopsy: single-institution experience.

OBJECTIVE: The objective of our study was to present the details and incidence of air embolism and needle track implantation in patients who underwent percutaneous CT-guided thoracic biopsy. MATERIALS AND METHODS: We retrospectively reviewed 1,400 percutaneous CT-guided thoracic biopsies during the period from August 1993 to August 2008. A case with air embolism was considered to be a patient with hypotension during or after biopsy and with an air embolism confirmed on CT. A needle track implantation was considered to be a mass in the needle track on the postbiopsy follow-up CT. RESULTS: There were three (0.21%) cases of air embolism. Air embolisms were confirmed in the left ventricle, coronary artery, ascending aorta, and pulmonary vein. The pulmonary venous wall was pathologically identified in one case. Although there were no fatalities, two patients needed resuscitation. Left hemiplegia occurred in one case, but it gradually disappeared. There were four (0.56%) cases of needle track implantation in 713 pathologically proven malignant thoracic biopsy cases with follow-up CT scans. Two were primary lung cancer and the others were lung metastasis (renal cell carcinoma and osteosarcoma). Implantation was found 4-7 months (mean, 5.6 months) after the biopsy, and size was 2.5-5.6 cm (mean, 3.5 cm). CONCLUSION: The incidence of air embolism with clinical symptoms and needle track implantation complicating percutaneous thoracic biopsy is more frequent than the previously reported rate.

The superior group of vessels in the falciform ligament: anatomical and radiological correlation.

AIM: The purpose of this study was to clarify the anatomical detail of the superior group of vessels in the falciform ligament in terms of the relationship with the internal thoracic vessels, inferior phrenic vessels, and the intrahepatic portal vein. MATERIALS AND METHODS: (1) Anatomical study: we dissected eight adult human cadavers (seven normal and one cirrhotic liver) to determine the relationship between the superior group of vessels in the falciform ligament, the internal thoracic vessels, and the inferior phrenic vessels. (2) Clinical study: we determined the origin and destination of the superior group of veins demonstrated in 8 of 4,006 patients with chronic liver disease who underwent the contrast enhanced CT scans. RESULTS: (1) Anatomical study: the superior group of vessels anastomosed the right (n = 4), left (n = 2), and both (n = 2) internal thoracic vessels. They also anastomosed the left (n = 4), right (n = 1), and both (n = 2) inferior phrenic vessels. (2) Clinical study: the origin of the veins was identified as the left medial branch (n = 4), left lateral branch (n = 1), both the lateral and medial branches (n = 1), and the vein from the umbilical portion (n = 2) of the left portal vein. The drainage vein was identified as the left (n = 3), right (n = 2), and the both (n = 1) internal thoracic veins. CONCLUSION: We demonstrated the anastomoses between the superior group of vessels of the falciform ligament, the internal thoracic vessels, the inferior phrenic vessels, and the intrahepatic portal vein. These pre-existing anastomoses would develop as porto-systemic shunt in patients with portal hypertension.

Balloon-occluded retrograde transvenous obliteration (BRTO) for a direct shunt between the inferior mesenteric vein and the inferior vena cava in a patient with hepatic encephalopathy.

A direct shunt between the inferior mesenteric vein and the inferior vena cava was detected in a patient with hepatic encephalopathy. The authors performed balloon-occluded retrograde transvenous obliteration (BRTO) for this shunt. Before the obliteration, the shunt was occluded by using a balloon catheter and it was confirmed that the portal venous flow was redirected to the liver. The encephalopathy disappeared immediately after BRTO. The improvement of the liver function, the disappearance of the shunt, and the increase in the size of the portal vein and liver volume were confirmed at computed tomography performed 5 months after treatment.

Signal flare phenomenon as active bleeding in retroperitoneal hematoma with hematocrit effect on dynamic CT scan: three clinical cases and experimental study based on a specific gravity theory.

The contrast medium was observed as a thin line indicating active bleeding in the cellular component and stayed at the boundary between the plasma and cellular components in liquefied hematomas. We could also reproduce the same phenomenon in an experimental study using human blood. The characteristic dynamic motion of the contrast medium demonstrated in the liquefied hematoma, which we have called the "signal flare" phenomenon, is a significant sign indicating active bleeding.

Anatomical variants of the lateral femoral circumflex artery: an angiographic study.

The descending branch of the lateral femoral circumflex artery (LFCA) has found recent use as a new arterial graft for coronary artery bypass grafting (CABG). Anatomical variants of the LFCA were assessed on femoral arteriograms obtained before CABG in 131 adult patients. The most common pattern, found in 78.6% of extremities, consisted of the LFCA arising from the deep femoral artery, and the arterial graft was selected from this pattern in 92.3% of patients in whom the descending branch of the LFCA was used for CABG.

CT-guided transthoracic core biopsy for pulmonary tuberculosis: diagnostic value of the histopathological findings in the specimen.

We evaluated the value of CT-guided transthoracic core biopsy for the diagnosis of mycobacterial pulmonary nodules. The 30 subjects in this study had pulmonary nodules that had been either diagnosed histopathologically as tuberculosis or were suspected as tuberculosis based on a specimen obtained by CT-guided transthoracic core biopsy. The histopathological findings, the existence of acid-fast bacilli in the biopsy specimens, and the clinical course of the patients after the biopsy were reviewed retrospectively. Two of the three histological findings for tuberculosis that included epithelioid cells, multinucleated giant cells and caseous necrosis were observed in 21 of the nodules which were therefore diagnosed as histological tuberculosis. Six of these 21 nodules were positive for acid-fast bacilli, confirming the diagnosis of tuberculosis. Thirteen of the 21 nodules did not contain acid-fast bacilli but decreased in size in response to antituberculous treatment and were therefore diagnosed as clinical tuberculosis. Seven nodules with only caseous necrosis were diagnosed as suspected tuberculosis, with a final diagnosis of tuberculosis being made in 4 of the nodules and a diagnosis of old tuberculosis in 2 nodules. Two nodules with only multinucleated giant cells were diagnosed as suspected tuberculosis with 1 of these nodules being diagnosed finally as tuberculosis and the other nodule as a nonspecific granuloma. When any two of the three following histopathological findings--epithelioid cells, multinucleated giant cells or caseous necrosis--are observed in a specimen obtained by CT-guided transthoracic core biopsy, the diagnosis of tuberculosis can be established without the detection of acid-fast bacilli or Mycobacterium tuberculosis.

Collateral venous pathways in the transverse mesocolon and greater omentum in patients with pancreatic disease.

OBJECTIVE: The purpose of this study was to describe the radiologic findings of the collateral venous pathways in the transverse mesocolon and the greater omentum associated with pancreatic diseases and to correlate these venous pathways and the accompanying arterial anatomy. CONCLUSION: The collateral pathway in the transverse mesocolon consists of the inferior mesenteric vein, left transverse colic vein, marginal vein of the transverse colon, and middle colic vein. The pathway in the greater omentum consists of anastomosis of the left and right epiploic veins deriving from the gastroepiploic vein. The former pathway is the vena comitans of Riolan's arch and the latter is the vena comitans of the arch of Barkow.