Junichiro Sanada

Hepatocelluar nodules in liver cirrhosis: hemodynamic evaluation (angiography- assisted CT) with special reference to multi-step hepatocarcinogenesis

To understand the hemodynamics of hepatocellular carcinoma (HCC) is important for the precise imaging diagnosis and treatment, because there is an intense correlation between their hemodynamics and pathophysiology. Angiogenesis such as sinusoidal capillarization and unpaired arteries shows gradual increase during multi-step hepatocarcinogenesis from high-grade dysplastic nodule to classic hypervascular HCC. In accordance with this angiogenesis, the intranodular portal supply is decreased, whereas the intranodular arterial supply is first decreased during the early stage of hepatocarcinogenesis and then increased in parallel with increasing grade of malignancy of the nodules. On the other hand, the main drainage vessels of hepatocellular nodules change from hepatic veins to hepatic sinusoids and then to portal veins during multi-step hepatocarcinogenesis, mainly due to disappearance of the hepatic veins from the nodules. Therefore, in early HCC, no perinodular corona enhancement is seen on portal to equilibrium phase CT, but it is definite in hypervascular classical HCC. Corona enhancement is thicker in encapsulated HCC and thin in HCC without pseudocapsule. To understand these hemodynamic changes during multi-step hepatocarcinogenesis is important, especially for early diagnosis and treatment of HCCs.

Groove pancreatic carcinomas: radiological and pathological findings

Abstract. The aim of this study was to clarify the characteristics of pancreatic head carcinomas mainly invading the groove between the duodenum and the pancreatic head. Nine patients with pathologically proven pancreatic head carcinomas underwent thin-slice dynamic CT, MR imaging, duodenal endoscopy, and angiography (seven patients). Plate-like masses within the groove region were seen in all cases, which showed hypointensity on T1-weighted images and slight hyperintensity on T2-weighted MR images. The masses appeared hypovascular in the early phase and delayed enhancement in the late phase of dynamic CT and MR imaging. On MR cholangiopancreatography, stenosis of intrapancreatic common bile duct was seen in all patients, whereas stenosis of the main pancreatic duct was seen in only three cases. Endoscopy revealed luminal narrowing of the duodenum in all patients, and duodenal mucosal biopsy demonstrated adenocarcinoma in seven patients. Abdominal arteriography showed serrated encasement of peripancreatic arteries in seven patients who received angiographic examinations. The CT and MR imaging findings of groove pancreatic carcinomas resemble those of groove pancreatitis. Differential diagnosis may be achieved by the pathological diagnosis of a biopsy specimen of the duodenal mucosa and arterial encasement on arteriography.

Endovascular Stent-Grafting for Infected Iliac Artery Pseudoaneurysms

We report two cases of acutely infected pseudoaneurysms of the iliac arteries, successfully treated with endovascular stent-grafting. Two patients underwent stent-graft treatment for erosive rupture of the iliac artery caused by surrounding infection. The first case is that of a 61-year-old man who had undergone Miles’ operation for an advanced rectal cancer. Postoperatively, he developed intrapelvic abscess formation, from which methicillin-resistant Staphylococcus aureus was cultured, followed by rupture of the right external iliac artery. The second case is that of a 60-year-old man who had a pseudoaneurysm of the left common iliac artery, which was contiguous with a left psoas muscle abscess, from which Streptococcus agalactiae was cultured. Both patients were successfully treated with only a stent-graft and antibiotic therapy, and remained symptom-free 12 months and 10 months later. Although endovascular stent-grafting should not be considered standard therapy for infected aneurysms, our cases suggest that it can result in repair of infected aneurysms even in the uncontrolled active stage.

Peritumoral rim enhancement of liver metastasis: hemodynamics observed on single-level dynamic CT during hepatic arteriography and histopathologic correlation.

Purpose The purpose of this work was to clarify the mechanism of peritumoral rim enhancement of metastatic liver cancer. Method Twenty-nine liver metastases of colon cancer were examined by single-level dynamic CT during hepatic arteriography, which was performed without table feed. We analyzed these findings and correlated them with the histopathologic findings. Results Eleven metastases were hypervascular and 18 were hypovascular. Early appearance of rim enhancement was seen in 3 of 10 hypervascular metastases and 17 of 18 hypovascular metastases (p < 0.01). The time of appearance and thickness of peritumoral rim enhancement showed no apparent correlation with the desmoplastic reaction or inflammation in the surrounding hepatic parenchyma. Conclusion Two types of intra- and peritumoral enhancement were observed. Peritumoral rim enhancement was considered to be due mainly to the drainage of blood flow from the tumor to the surrounding hepatic parenchyma in hypervascular metastasis or increased arterioportal shunts surrounding the tumor in hypovascular metastasis.

Accumulation of Iodized Oil Within the Non-Neoplastic LiverAdjacent to Hepatocellular Carcinoma via the Drainage Routes of theTumor After Transcatheter Arterial Embolization

AbstractPurpose: After transcatheter arterial embolization (TAE) with iodized oil (Lipiodol), a relatively dense accumulation of Lipiodol is often seen in the nontumorous liver adjacent to a hypervascular hepatocellular carcinoma (HCC) nodule. We compared this phenomenon with the findings obtained with single-level dynamic CT during hepatic arteriography (SLDCTHA) and presumed its possible mechanism. Methods: Fifty-six patients with HCC underwent hepatic angiography including SLDCTHA followed by segmental or subsegmental TAE with a mixture of an anticancer drug and Lipiodol. We compared the drainage area of the HCC depicted on SLDCTHA with the Lipiodol accumulation in the nontumorous liver adjacent to the HCC on CT after TAE (LpCT). Results: In 26 of the 56 patients, a definite corona enhancement around the HCC, suggesting the drainage of blood from the tumor into the surrounding liver parenchyma, was seen on the late phase of SLDCTHA. In 17 of these 26 patients (65.4%), LpCT showed a more intense accumulation of Lipiodol in the nontumorous liver adjacent to the HCC that corresponded to the drainage area revealed on SLDCTHA. Conclusion: The drainage of blood from the HCC was considered to be a possible mechanism of the accumulation of Lipiodol in the nontumorous liver adjacent to the HCC.

Clinical application of a curved nitinol stent-graft for thoracic aortic aneurysms.

Purpose: To evaluate the clinical efficacy of a curved nitinol stent-graft for repair of thoracic aortic aneurysms. Methods: The Matsui-Kitamura stent-graft (MKSG), composed of a self-expanding nitinol stent and polyester fabric, was shaped to match the aortic curvature of 11 patients (6 men; mean age 72.6 years, range 33–90) with 6 true and 5 false aneurysms of the distal arch or proximal descending aorta. The delivery system was an 18 or 20-F J-shaped sheath combined with a preloader-type introducer. The original mean proximal neck length was 16.4 mm, but 4 patients received an axilloaxillary bypass to lengthen the neck. Although the mean corrected proximal neck length was 21.9 mm (overall), 5 cases still had proximal necks <15 mm long. Results: All curved MKSGs were successfully deployed in the correct position and fitted to the curvature of the aortic arch, achieving complete aneurysm exclusion in 8 (73%) cases. The other 3 repairs displayed early endoleaks; 1 received an additional MKSG, but the other 2 are being observed. Thirty-day mortality was 0%. One patient developed transient renal failure requiring hemodialysis; no neurological complications were observed. Conclusions: Endovascular repair of thoracic aortic aneurysms using curved MKSGs appears to be feasible and clinically effective. A tighter fit of the device to the curvature of the aortic arch may exclude distal arch aneurysms despite a short proximal neck.

Spontaneous Hemothorax in Neurofibromatosis Treated with Percutaneous Embolization

We evaluated the effectiveness of transcatheter arterial coil embolization therapy for the treatment of spontaneous hemothorax followed by aneurysm rupture in neurofibromatosis patients. Three patients were treated for massive hemothorax caused by arterial lesions associated with neurofibromatosis. Bleeding episodes were secondary to ascending cervical artery aneurysm and dissection of vertebral artery in 1 patient, and intercostal artery aneurysm with or without arteriovenous fistula in 2 patients. Patients were treated by transarterial coil embolization combined with chest drainage. In 1 patient, the ruptured ascending cervical artery aneurysm was well embolized but, shortly after the embolization, fatal hemorrhage induced by dissection of the vertebral artery occurred and the patient died. In the other 2 patients, the ruptured intercostal artery aneurysm was well embolized and they were successfully treated and discharged. Transcatheter arterial coil embolization therapy is an effective method for the treatment of spontaneous hemothorax followed by aneurysm rupture in neurofibromatosis patients.

Stent-Graft Repair of a Mycotic Left Subclavian Artery Pseudoaneurysm

Purpose: To report successful stent-graft treatment of a mycotic pseudoaneurysm of the left subclavian artery in an immunosuppressed patient. Case Report: A 17-year-old immunosuppressed woman undergoing treatment for recurrent leukemia developed persistent fever and 2 episodes of hemoptysis. A contrast-enhanced computed tomographic (CT) scan demonstrated a saccular aneurysm of the left subclavian artery, which was considered to be a mycotic aneurysm caused by erosive fungal infection from the lung. The pseudoaneurysm was treated with a homemade stent-graft consisting of a nitinol stent and a polyester fabric. A type II endoleak present at the end of the procedure appeared to have sealed spontaneously on the CT scan at 3 days. No neurological deficit or ischemic symptoms of the left arm were noted during the follow-up, which lasted until the patient died 11 months later after rejecting a second bone marrow transplant. Conclusions: Endovascular repair may be an alternative to open surgery for the management of mycotic aneurysms of the subclavian artery.

An experimental study of endovascular stenting with special reference to the effects on the aortic vasa vasorum

AbstractPurpose: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. Methods: Eight bare stents and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4–45 weeks after stent placement. The vasa vasorum was evaluated by microstereoscopy with vascular casting, and the histopathology of the aortic wall was examined by light microscopy. Results: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media were avascular. In the stented segment, vascular dilatation and proliferation of vasa vasorum, medial atrophy, and intimal hyperplasia were observed, more prominent for covered stents than for bare stents. Conclusion: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, probably due to hypoxia in the aortic wall.

Feeding artery of laryngeal and hypopharyngeal cancers: role of the superior thyroid artery in superselective intraarterial chemotherapy.

The purpose of this study was to elucidate the role of the superior thyroid artery in intra-arterial infusion chemotherapy for laryngeal and hypopharyngeal cancers. Thirty-nine patients with laryngeal cancer and 29 patients with hypopharyngeal cancer underwent intra-arterial infusion chemotherapy. We performed a retrospective analysis of the feeding arteries confirmed by computed tomography during selective arteriography and compared the results with the extent of the tumors. In 14 of 39 laryngeal and 15 of 29 hypopharyngeal cancers, the tumor did not cross the midline (group 1). In the remaining 25 and 14 cancers, respectively, the tumor crossed the midline or located in the center (group 2). For 13 of 14 laryngeal and 7 of 15 hypopharyngeal cancers in group 1 and for 6 of 25 laryngeal cancers in group 2, the entire tumor was contrast enhanced by the ipsilateral superior thyroid and/or superior laryngeal artery. For 12 of 25 laryngeal and 1 of 14 hypopharyngeal cancers in group 2, the entire tumor was contrast enhanced by the bilateral superior thyroid artery. For the other patients, infusion via the other arterial branches such as the inferior thyroid and the lingual arteries were needed to achieve contrast enhancement of the entire tumor. Superselective intra-arterial chemotherapy for laryngeal cancer from the superior thyroid artery is appropriate, whereas that for hypopharyngeal cancer is less sufficient. To accomplish contrast enhancement of the entire tumor, additional intra-arterial infusion from other arteries such as the inferior thyroid artery is often necessary.