Shunsuke Nosaka

Syndromes Associated with Vascular Tumors and Malformations: A Pictorial Review

Use of the International Society for the Study of Vascular Anomalies (ISSVA) classification system has been strongly recommended in recent years because of the need for separate therapeutic measures for patients with vascular tumors and malformations. In the ISSVA classification system, vascular tumors, which are neoplastic, are distinguished from vascular malformations, which are caused by vascular structural anomalies and are not neoplastic, on the basis of the presence or absence of neoplastic proliferation of vascular endothelial cells. It is important that radiologists be familiar with the development, diagnosis, and treatment of vascular tumors and malformations, especially the imaging features of low- and high-flow vascular malformations. Some vascular tumors and malformations develop in isolation, whereas others develop within the phenotype of a syndrome. Syndromes that are associated with vascular tumors include PHACE syndrome. Syndromes that are associated with vascular malformations include Sturge-Weber, Klippel-Trénaunay, Proteus, blue rubber bleb nevus, Maffucci, and Gorham-Stout syndromes, all of which demonstrate low flow, and Rendu-Osler-Weber, Cobb, Wyburn-Mason, and Parkes Weber syndromes, all of which demonstrate high flow. Because imaging findings may help identify such syndromes as systemic, it is important that radiologists familiarize themselves with these conditions.

The classification based on intrahepatic portal system for congenital portosystemic shunts

BACKGROUND/PURPOSE Liver transplantation was previously indicated as a curative operation for congenital absence of portal vein. Recent advances in radiological interventional techniques can precisely visualize the architecture of the intrahepatic portal system (IHPS). Therefore, the therapeutic approach for congenital portosystemic shunt (CPS) needs to be reevaluated from a viewpoint of radiological appearances. The aim of this study was to propose the IHPS classification which could explain the pathophysiological characteristics and play a complementary role of a therapeutic approach and management for CPS. METHODS Nineteen patients with CPS were retrospectively reviewed. The median age at diagnosis was 6.8 years old. Eighteen of these patients underwent angiography with a shunt occlusion test and were classified based of the severity of the hypoplasia of IHPS. RESULTS The eighteen cases who could undergo the shunt occlusion test were classified into mild (n=7), moderate (n=6) and severe types (n=5) according to the IHPS classification. The IHPS classification correlated with the portal venous pressure under shunt occlusion, the histopathological findings, postoperative portal venous flow and liver regeneration. Shunt closure resulted in dramatic improvement in the laboratory data and subclinical encephalopathy. Two patients with the severe type suffered from sepsis associated with portal hypertension after treatment, and from the portal flow steal phenomenon because of the development of unexpected collateral vessels. The patients with the severe type had a high risk of postoperative complications after shunt closure in one step, even if the PVP was relatively low during the shunt occlusion test. CONCLUSION The IHPS could be visualized by the shunt occlusion test. The IHPS classification reflected the clinicopathological features of CPS, and was useful to determine the therapeutic approach and management for CPS.

Technical considerations of living donor hepatectomy of segment 2 grafts for infants

BACKGROUND The selection of an adequate graft to mitigate the problems associated with a large-for-size graft is essential to ensure the success of liver transplantation for smaller children. Reduced left lateral segment (LLS) grafts have been introduced to overcome this issue. METHODS Five infants underwent living donor liver transplantation (LDLT) with segment 2 grafts. In the preoperative assessment, the graft-to-recipient weight ratio (GRWR) and the ratio of the thickness of the donor LLS were used as a reference index for graft size matching, and a 3-dimensional (3D) computer-generated model of the donor liver was used for the analysis of the intrahepatic vasculature. During the donor operation, the relevant portal vein branches feeding to the reduced part of segment 3 were first exposed and divided, and then the parenchymal transection was performed. RESULTS Segment 2 grafts were selected in 3 cases and reduced segment 2 grafts were selected in the other 2 cases. The graft reduction was achieved with 46.6 ± 8.2% of the actual LLS, and thus the GRWR was reduced from 5.33 ± 2.09% to 2.70 ± 0.82%. The actual graft thickness was reduced by approximately half after the graft reduction. Primary abdominal closure was performed in all of the recipients. No surgical complications occurred in any of the donors or recipients. CONCLUSION A segment 2 graft could be a valuable option for graft type selection in LDLT for smaller children. Precise planning using a 3D computer-generated model of the donor liver and meticulous operative procedures are necessary to obtain a viable graft.

Imaging of vascular tumors with an emphasis on ISSVA classification

The International Society for the Study of Vascular Anomalies (ISSVA) classification is becoming the international standard classification system for vascular tumors and vascular malformations. The ISSVA classification strictly distinguishes vascular tumors (neoplastic lesions) from vascular malformations (non-neoplastic lesions) based on whether there is a proliferation of vascular endothelial cells present, and it is an extremely useful classification system for determining therapeutic measures. For vascular tumors, it is clinically significant in terms of discriminating infantile hemangioma and rapidly involuting congenital hemangioma, which are expected to spontaneously regress, from other vascular tumors requiring treatment. Needless to say, clinical courses are important for diagnosis, and it is also important for radiologists to understand imaging findings on vascular tumors because such tumors have unique findings on diagnostic images. In this paper, vascular tumors are classified based on the ISSVA classification, and clinical and imaging findings are reviewed.

Outcomes of prenatally diagnosed sacrococcygeal teratomas: the results of a Japanese nationwide survey

BACKGROUND/PURPOSE Few large multicenter surveys have been performed on sacrococcygeal teratomas (SCTs) describing both the prenatal and postnatal courses. The aim of this study was to review and report on the prenatal surveillance and postnatal outcome of a large cohort of fetuses with SCTs in Japan. METHODS A nationwide retrospective cohort study was conducted on 97 fetuses prenatally diagnosed with SCTs between 2000 and 2009. The prenatal course, perinatal data, and postnatal outcome were reviewed. RESULTS Eleven pregnancies were terminated before 22 weeks of gestation. Of the 86 remaining fetuses, 3 died in utero, and 83 were delivered. Three infants died before surgery, and 8 infants died after excisional surgery. The overall mortality was 26%, with a mortality excluding terminations of 16%. The gestational age at delivery was younger than 28 weeks in 5, 28 to 31 weeks in 13, 32 to 36 weeks in 27, and 37 weeks or more in 37 cases, with mortality rates of 60%, 38%, 11%, and 0%, respectively. The tumor component was predominantly cystic in 54 and predominantly solid in 32 cases, with mortality rates of 2% and 33%, respectively. CONCLUSIONS The overall mortality of prenatally diagnosed SCTs excluding terminations was 16%. Early delivery and predominantly solid component tumors were associated with an increased risk of mortality.

Correlation of CT values, iodine concentration, and histological changes in the thyroid.

PURPOSE We have reported that in the thyroid, there is a linear correlation between iodine concentrations and CT values. However, the slope of the regression line was about three times as large as that in KI solutions. We investigated the factor(s) contributing to the increment of the slope of the regression line in the thyroid. METHOD Solutions of NH4I and thyroid hormones were used to investigate the regression line. Thirty-six thyroids were evaluated to investigate the correlation between the iodine concentrations and the area ratio of thyroid follicles, which were measured by preoperative CT and from tissue slices, respectively. RESULTS The slopes of the regression lines in the solutions were almost identical to those in KI solutions. In the thyroid, iodine concentrations were logarithmically correlated with the area ratio of follicles. CONCLUSION The decrease in CT values not only revealed a decrease of iodine concentration in the thyroid but also represented an increase of follicular cells and/or interstitial structures in the volume ratio secondary to it.

Clinical Features and Prognosis of Generalized Lymphatic Anomaly, Kaposiform Lymphangiomatosis, and Gorham-Stout Disease.

Complex lymphatic anomalies are intractable lymphatic disorders, including generalized lymphatic anomaly (GLA), Gorham–Stout disease (GSD), and kaposiform lymphangiomatosis (KLA). The etiology of these diseases remains unknown and diagnosis is confused by their similar clinical findings. This study aimed to clarify the differences in clinical features and prognosis among GLA, KLA, and GSD, in Japanese patients.

Critical infantile hepatic hemangioma: results of a nationwide survey by the Japanese Infantile Hepatic Hemangioma Study Group

BACKGROUND The current survey aimed to describe the clinical features of critical infantile hepatic hemangioma (IHH) and the implications of recent treatments. MATERIALS AND METHODS A nationwide survey of critical IHH patients treated between 2005 and 2010 was performed in all 117 registered pediatric surgical hospitals in Japan. As a result, 19 patients were identified and reviewed using a statistical analysis. RESULTS Abdominal distention (47.4%), high-output cardiac failure (47.4%), coagulopathy (42.1%), and respiratory distress (31.6%) were the major symptoms. Three patients died (1 of coagulopathy, 1 of cardiac failure, and 1 of both). An accompanying portovenous shunt was also highlighted. Infantile hepatic hemangioma was totally insensitive to steroid treatment in 3 (23.1%) of the 13 patients, and 9 (47.4%) of the 19 patients required other treatments. Surgical resection and β-blocker improved the hematologic data, whereas hepatic arterial ligation and embolization seemed to produce a limited effect. Among the dead patients, several hematologic parameters were significantly worse: the thrombocyte count (pretherapeutic: 73,000 vs 300,000/mm(3), dead vs survivor, respectively [P < .03]; posttherapeutic: 66,000 vs 388,700/mm(3) [P < .003]) and the prothrombin time (posttherapeutic, 35.0 vs 12.1 seconds [P < .0001], dead vs survivor, respectively). CONCLUSION For critical IHH cases with steroid-insensitive hematologic disorders, alternative treatments including β-blocker therapy, surgery, and liver transplantation should be considered.

Utility of spinal MRI in children with anorectal malformation

BackgroundThe association between spinal cord anomalies and imperforate anus is well recognized. Until now, the incidence of tethered cord has been assumed to be higher in patients with high-type imperforate anus. However, recent reports suggest that tethered cord is as common in patients with a low lesion as in those with a high lesion.ObjectiveTo review the incidence of spinal cord anomalies in those with a low lesion and those with a high (including intermediate) anorectal malformation (ARM), and to determine the best diagnostic imaging strategy.Materials and methodsA group of 50 consecutive patients with postoperative ARM and in whom spinal MRI had been performed were identified retrospectively. We reviewed and compared the following factors between those with a high lesion and those with a low lesion: (1) clinical symptoms, (2) spinal cord anomalies, and (3) vertebral anomalies.ResultsThe incidence of spinal cord anomalies was no different between those with a high lesion and those with a low lesion, and spinal cord anomalies were present regardless of the presence of vertebral anomalies or symptoms.ConclusionOwing to the high incidence of spinal cord anomalies in patients with imperforate anus, MRI is the best imaging tool for detecting such anomalies regardless of the level of the lesion.

Living donor liver transplantation for congenital absence of the portal vein with situs inversus

Received March 10, 2009; accepted May 17, 2009.Congenital absence of the portal vein (CAPV) is a raredisorder that may lead to the development of hepaticneoplasms, hepatic encephalopathy, pulmonary hyper-tension (PH), and hepatopulmonary syndrome (HPS).The portal vein develops by selective involution of thevitelline venous system, and associated abnormalitiesmay result in CAPV. Some patients with CAPV are di-agnosed at the time of neonatal screening for hyper-galactosemia.