Jpn J Intervent Radiol Vol.21 No.4 2006

State of the Art
Interventional Radiology for Management of Vascular Anomalies
- from Clinical Diagnosis to Surgical Treatment, the Indication and Limitation of the Techniques -

1. Classification and Strategy for Vascular Malformations
Department of Medical Imaging, Kawasaki Medical School
Shigeki Imai, Shigeru Watanabe, Hiroki Higashi

 An understanding of the anatomy and pathophysiology of congenital vascular malformations has advanced remarkably in the past 20 years, stimulated by technologic developments allowing new treatment possibilities and by individuals who have refined the scientific medical basis for diagnosing and classifying these complex lesions. Mulliken advocate the principle that two distinct types of vascular abnormalities exist - hemangiomas and vascular malformations - each with distinctive clinical, cellular, hematologic, radiologic, and skeletal dif ferences. The treatment policy has been decided based on the classification that the International Society for the Study of Vascular Anomalies (ISSVA) recommended recently.
 Hemangiomas are benign vascular tumors, generally having a predictable proliferative phase in the patient between 2 weeks and 18 months of age, and an equally predictable involuntionary stage ranging from 2 to 6 years. Because they are self-limited, they usually require no treatment. However, a few hemangiomas do require medical, surgical, or interventional therapy.
 Vascular malformations are congenitally abnormal vessels and vascular connections that are present at birth and grow with the child, often expanding rapidly as vascular spaces fill in response to the hormones of adolescence and pregnancy, trauma, or other stimuli. Vascular malformations have few proliferating cells and do not involute and cannot be encouraged to regress with steroids, irradiation, or other measures effective for hemangiomas. For these reasons, vascular malformations are often problematic, and affected patients are frequently candidates for surgical treatment, interventional therapy, or both.

Key words
● Vascular malformation
● Arteriovenous malformation
● Venous malformation

2. Pathology of Hemangiomas and Vascular Malformations
Department of Pathology, Fukuoka Red Cross Hospital
Yutaka Nakashima

 Vascular anomalies are divided into two major categories, i.e., vascular tumors and vascular malformations, in the classification of the International Society for the Study of Vascular Anomalies (ISSVA). Hemangioma of infancy is the most representative vascular tumor consisting of small blood vessels lined with endothelial cells. In the proliferating phase of the tumor, the endothelial cells show high proliferative activity revealed by a high MIB-1 labeling index. GLUT1 is a specific and useful marker for hemangioma of infancy because it is expressed in endothelial cells not only in the proliferating phase but also in the involuting phase, and because it is not expressed in other vascular tumors or vascular malformations.
 Vascular malformations are defined as structural malformations of the vasculature and are composed of capillaries, veins, arteries, lymphatics or combinations of these elements. The turnover of endothelial cells is normal and almost no MIB-1-positive cells are obser ved.
 Normal development of the vasculature occurs via vasculogenesis, angiogenesis and vascular remodeling. The recent progress in genetics and molecular biology has shown the relationship between the normal developmental processes and vascular anomalies and found various molecular factors that take part in the pathogenesis of the diseases.

Key words
● Pathology
● Hemangioma
● Vascular malformation

3. Surgical Approach for Vascular Malformations
Department of Plastic and Reconstructive Surgery, Sapporo Medical University School of Medicine
Takatoshi Yotsuyanagi, Kyori Ezoe, Tamotsu Saito

 We described here a surgical approach for vascular malformations from the view point of plastic surgeons.
 The surgical removal of the tumor is the most effective procedure but needs some cautions. When planning the operation, the position and size of the tumor, and the possibility of massive bleeding should be kept in mind. It is desirable that the tumor be completely removed but a partial resection should be achieved if the important tissues are included in the tumor or massive bleeding is anticipated. After removal of the tumor, many variations of regional skin flaps or skin grafts are applied according to the reconstructive needs. It is important that the technique which provides functional and esthetic reconstruction with texture and color matches be selected. The concept of esthetic unit is very useful for these purposes.
 We should also pay attention to postoperative care because the recurrence or an unexpected event such as prolonged laryngeal edema in the neck region sometimes occurs. For children, conservative planning is recommended to preserve function and to consider their growth.

Key words
● Operation
● Skin flap
● Skin graft
● Esthetic unit

4. Laser Treatment in Vascular Tumors and Malformations
Division of Plastic Surgery, Tokyo Rosai Hospital
Shoji Watanabe

 Laser photocoagulation has been applied for congenital as well as acquired vascular lesions for many years. For congenital vascular malformations, the flashlamp-pumped pulsed dye laser, Nd-YAG laser, and KTP laser are available for capillary and venous malformations. Lasers have great advantages over surgery or sclerotherapy, to be applied easily for younger age group because the effect is generally local and the maneuver bloodless. Even though the effect seems not to be permanent for many cases of extensive vascular malformations, these lasers are very useful to be for coagulation of superficial small dilated capillaries and veins, and the combination with laser and sclerotherapy leads to minimize skin damage as a complication of sclerotherapy.

Key words
● Laser
● Nd-YAG
● Dye laser

5. Transarterial Embolization of Arteriovenous Malformations Using Particulate Agents
Department of Radiology, Rinku General Medical Center, Izumisano City Hospital
Tetsuro Nakazawa
Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine
Keigo Osuga, Koji Mikami, Hiroki Higashihara, Noboru Maeda, Kaname Tomoda, Hironobu Nakamura
Gate Tower Institute for Image Guided Therapy
Shinichi Hori

 Up to now, it has been difficult to treat vascular malformations only with surgery. Less invasive inter ventional radiological techniques increase the range of treatment options including transcatheter or percutaneous embolotherapy. For arterial-supplied lesions like arteriovenous malformations (AVMs), transarterial embolization (TAE) is a treatment of choice using various embolic agents. Above all, particulate agents are expected to be used easily for preoperative devascularization or symptom palliation. Gelatin sponge particles may achieve temporar yvessel occlusion, and irregular-shaped polyvinyl alcohol particles will aggregate proximally and are more likely to recruit collaterals. Thus, non-absorbable calibrated microspheres are more suitable in spite of the risk of migration into the lung when intralesional shunts are significant.
 Herein, we describe the role and limitations of TAE for AVMs using par ticulate agents featuring our experience with superabsorbent polymer microspheres (SAP-MS).

Key words
● Arteriovenous malformation (AVM)
● Transarterial embolization (TAE)
● Particulate embolic agents
● Microspheres

6. NBCA Embolization for Angioma & Arteriovenous Malformation
Department of Radiology, Juntendo Urayasu Hospital, Juntendo University, School of Medicine.
Yuo Iizuka, Shouiti Kikushima, Takanori Kakihara, Nobutaka Yoshimura
Hidekazu Nagasawa, Takao Kimizuka, Masayuki Akamatsu, Yukiharu Sumi

 N-Butyl-cyanoacr ylate is a liquid adhesive non-absorbable embolic material whose permeability is very stable. It must be liquid at the time of injection and should solidify when it has reached the pathological angioarchitecture, producing an endovascular cast of the area without passing to the venous circulation or distal arterial territory. If superselectivity is accomplished and no normal or endangered vessels are present, one can inject acrylic as a continuous column to produce an intravascular cast. An important part of the management of angioma is educating the patient. NBCA embolization for arteriovenous malformation can be carried out as a unique treatment, the intended goal being partial and targeted, palliative, curative, or in combination with surger y or stereotactic radiosurger y. It may be given as elective treatment or in emergent fashion, depending on the indication and circumstances. The indication to use this embolic material should be well considered in the clinical management of angioma and arteriovenous malformation.

Key words
● Hemangioma
● Arteriovenous Malformation
● N-Butyl-Cyanoacrylate

7. Percutaneous Sclerotherapy Using Polidocanol for Hemangiomas and Vascular Malformations
Department of Plastic and Reconstructive Surgery, Hokkaido University Graduate School of Medicine
Satoru Sasaki, Hiroshi Furukawa, Mitsuru Sekido, Akihiko Oyama, Munetomo Nagao, William Mol, Yuhei Yamamoto
1st Department of Physiology, Shinshu University School of Medicine
Yoshiko Kawai

 The indications, attention and complications in sclerotherapy using polidocanol for vascular malformations and hemangiomas are mentioned in this ar ticle based on the authors’ experience in sclerotherapy for more than 300 cases of vascular malformations. In comparison with the other sclerosing agents, i.e. ethanol, polidocanol is much less painful to inject and has a lower complication rate, however, it has relatively weak sclerosing power and has a risk of cardiac suppression. The utility of polidocanol is very high particularly in the treatment of outpatients with small and slow-flow lesions. In addition, it is useful also as an adjunctive sclerosing agent for superficial part of vascular lesion which is treated with a strong agent like ethanol. It can be said that polidocanol is safe and easy to use in the treatment of vascular anomalies if excess dosage is avoided.

Key words
● Polidocanol
● Sclerotherapy
● Hemangioma
● Vascular malformation

8. Ethanolamine Oleate Sclerotherapy for Symptomatic Vascular Malformation / Hemangioma
Department of Radiology, Division of Plastic and Reconstructive Surgery1), Oral Surgery2),
Sapporo Medical University, School of Medicine
Hideki Hyodoh, Masakazu Hori, Yoko Usami, Naoki Hirokawa
Kazumitsu Koito, Masato Hareyama, Takatoshi Yotsuyanagi1), Akira Yamaguchi2)

 Peripheral vascular malformations are now described according to accepted guidelines, and the principle of proper treatment (nidus sclerotherapy) is becoming clear. Non-invasive imaging in association with clinical findings is critical in establishing the diagnosis, evaluating the extent of the malformation, and planning appropriate treatment. MR imaging is useful not only in making a correct diagnosis but also in measuring its volume for sclerotherapy. When a patient suffers clinical complications, nidus sclerotherapy becomes mandatory. If the vascular malformation retains bloodflow to a drainage vein during nidus opacification, flow control is necessary to achieve Ethanolamine Oleate sclerosant stasis within the nidus. An interventional approach is sometimes needed in the treatment of a high-flow lesion. A dedicated team approach is necessary for appropriate management in most cases.

Key words
● Vascular malformation
● Sclerotherapy
● Ethanolamine Oleate

9. IVR Treatment Using Ethanol for Hemangioma and Vascular Malformation
Department of Radiology, Kawasaki Medical School
Hiroki Higashi, Shigeki Imai, Naoto Egashira, Shigeru Watanabe
Department of Radiology, Yasu Hospital
Hiroshi Shirai

 Vascular malformation can cause various clinical signs and symptoms, such as pain, functional impairment, cosmetic problems, and bleeding. Although conventional treatment consists of surgical resection, this procedure is associated with post-operative complications. Treatments such as percutaneous embolosclerotherapy and sclerotherapy have attracted attention as less
invasive alternatives for the treatment of these lesions. Ethanol is considered to be a suitable drug for the treatment of this disorder, due to its high efficacy. However, its use carries the risk of skin damage and other complications, and requires mastery of treatment techniques.

Key words
● Vascular malformation
● Embolosclerotherapy
● Absolute ethanol

Original Article
Heat Distribution in Radiofrequency Ablation for Bone ;An Experimental Study
Department of Radiology, Tottori University
Akira Adachi, Toshio Kaminou, Masayuki Hashimoto, Kimihiko Sugiura,Yasunobu Takaki, Tsuyoshi Kawai, Toshihide Ogawa
Department of Radiology, Yonago Medical Center
Yasufumi Ouchi
Department of Radiology, Hakuai Hospital
Kiyoshi Nakamura
Department of Radiology, Sanin Rosai Hospital
Takashi Ihaya

 Purpose:To assess the safety of percutaneous radiofrequency ablation (RFA) for bony lesions with cortical defect, the heat distribution around the tibial bone with cortical defect was measured during RFA.
 Material and method : Seven fresh pig cadaver tibial bones were obtained and small cortical bone defect was created. A water-cooled single radiofrequency needle was inserted directly into the marrow canal,and the tip of the needle was positioned at the center of the canal. Two temperature sensors were positioned adjacent to the bone with or without cortical defect and the heat distribution was monitored during ablation.
 Result : The exposure time ranged from 100 to 360 seconds (average 201.0 seconds). The temperature just outside of the cortical bone defect was elevated up to 51 degrees on the average, but the temperature just outside of the cortical bone with out defect remained 35 degrees on average.
 Conclusion : The heat distribution around the cortical defect reached over 45 degrees which could be cytotoxic for the spinal cord and peripheral nerves. In RFA for vertebral tumor with cortical destruction, spinal cord or nerve root injury may occur.

Key words
●Radiofrequency ablation
●Bone tumor
●Heat distribution
●Nerve injury

Case Report
Two Cases of Chronic Mesenteric Ischemia Treated by Endovascular Stent Placement in theSuperior Mesenteric Artery
Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences
Sadao Hayashi, Yasutaka Baba, Kazuto Ueno, Tomokazu Umanodan
Takuro Kamiyama, Masayuki Nakajo
Department of Surgery, National Hospital Organization Kagoshima Medical Center
Toshiaki Miyazaki

 Chronic mesenteric ischemia (CMI) is caused by stenosis or occlusion of one or more mesenteric arteries. CMI produces gastrointestinal symptoms such as nausea, vomiting, postprandial abdominal pain and diarrhea. Sometimes CMI is responsible for weight loss. But it is difficult to prove the relationship between clinical symptoms and arterial stenosis. Generally, CMI is suspected by the combination of medical history and exclusion of other diseases with abdominal pain.
 CMI is a rare presentation of atherosclerosis. Recent reports showed the feasibility and efficiency of stent placement in visceral artery stenosis for the treatment of CMI. We present two cases of CMI treated by stent placement for superior mesenteric artery stenosis. Palmaz Genesis was used for the severe stenotic lesion because of its lower profile. Abdominal pain was successfully relieved by this procedure.

Key words
●Chronic mesenteric ischemia
●Superior mesenteric artery

Technical Note
Improvement of an Incompletely Opened Greenfield Filter Using Balloon Catheter to Prevent Migration
Department of Radiology, Nara Prefectural Nara Hospital
Takeshi Wada, Tetsuya Yoshioka, Noriko Horikawa

 The inferior vena cava (IVC) filter is one of established therapeutic options to prevent recurrence of pulmonary embolism , although some complications have been previously reported.
 We encountered an unusual procedural complication during transfemoral percutaneous placement ofa titanium Greenfield vena caval filter, in which full expansion was not obtained. We report a technique for adjusting the position of the filter legs employed in the present case.
 To prevent filter migration, an 8F occlusion balloon catheter was placed through the same access beyond the apex of the filter and was inflated. Then, with manipulation of a 4F pigtail catheter, all legs of the filter fully opened. The struts distributed more evenly in the IVC.
 In cases in which it is dif ficult for snaring, the method described in this report may be useful.

Key words
●IVC filter
●Balloon catheter