Kan Takeda

Percutaneous Radiofrequency Ablation of Lung Neoplasms: Initial Therapeutic Response

PURPOSE To evaluate the feasibility, safety, and initial therapeutic effect of radiofrequency (RF) ablation in the treatment of unresectable malignant lung tumors. MATERIALS AND METHODS Fifty-four lung neoplasms in 31 patients were treated with RF ablation. Thirteen tumors were primary lung cancers and 41 were pulmonary metastases. Tumor sizes ranged from 0.7 to 6.0 cm, with a mean size of 2.7 +/- 1.3 cm. After the RF electrode was placed in the tumor with computed tomographic (CT) fluoroscopic guidance, RF energy was applied. Initial therapeutic response was evaluated by (18) F fluorodeoxyglucose positron emission tomography (FDG-PET) and contrast-enhanced CT. The disappearance of FDG uptake on PET images and tumor enhancement on CT images were considered to indicate complete tumor necrosis. Complete necrosis rates were evaluated according to tumor size and type (primary or secondary lung neoplasm). RESULTS RF ablation was technically successful in all lesions. Complete necrosis was achieved in 32 of the 54 tumors (59%) after initial RF session. There was a significant difference in the rate of complete tumor necrosis between tumors 3 cm or less and tumors larger than 3 cm (69% vs. 39%; P <.05). Tumor type did not influence complete necrosis rates. Lung abscesses developed in two patients with large tumors. CONCLUSION Lung RF ablation is a feasible, relatively safe, and promising treatment for unresectable lung neoplasms. Tumor size is an important factor in achieving complete tumor necrosis.

Transcatheter arterial embolization of ruptured pseudoaneurysms with coils and n-butyl cyanoacrylate.

PURPOSE To evaluate the clinical efficacy of transcatheter arterial embolization with n-butyl cyanoacrylate (NBCA) for ruptured pseudoaneurysms, which are difficult to control by coil embolization alone. MATERIALS AND METHODS Ruptured pseudoaneurysms developed at the celiac trunk (n = 1), gastroduodenal artery (n = 2), pancreatic arcade (n = 1), hepatic artery (n = 3), renal artery (n = 1), and intercostal artery (n = 1) in nine patients. NBCA was mixed with iodized-oil (1:2) and injected via the 3-F microcatheter under fluoroscopic guidance, after the catheter was advanced close to the pseudoaneurysm. Coil embolization was performed to control blood flow before administration of NBCA in seven patients. NBCA was injected immediately after coil embolization in four patients. Embolization with NBCA was performed for recurrent bleeding that occurred within 1-21 days (mean, 10.7 days) after initial coil embolization in three patients. Two patients with peripheral pseudoaneurysms underwent embolization with NBCA alone. RESULTS The NBCA mixture was visible under fluoroscopy, and was useful in monitoring the embolization process and deciding the endpoint. Embolization was technically successful without major complications in all patients. Pseudoaneurysms and afferent and efferent arteries were eliminated immediately after embolization. Bleeding was stopped after embolization in all cases. Rebleeding did not occur in any patient during their follow-up periods of 0.7-69.5 months (mean, 17.9 months). CONCLUSION Embolization with NBCA is a feasible and useful treatment for ruptured pseudoaneurysms, which are difficult to control by coil embolization alone.

Radiofrequency ablation combined with chemoembolization in hepatocellular carcinoma: treatment response based on tumor size and morphology.

PURPOSE To evaluate local therapeutic efficacy of radiofrequency (RF) ablation after chemoembolization for hepatocellular carcinoma (HCC) based on tumor size and morphology. MATERIALS AND METHODS Sixty-four patients underwent RF ablation under ultrasonographic or real-time computed tomographic (CT) fluoroscopic guidance within 2 weeks after chemoembolization. One hundred eight lesions were treated. Sixty-five lesions were small (<or=3 cm), 32 were intermediate in size (3.1-5 cm), and 11 were large (5.1-12 cm). Seventy-four of the HCCs were nodular lesions and the other 34 were nonnodular (multinodular and infiltrative) lesions. Response to treatment was evaluated by dynamic enhanced CT and magnetic resonance imaging. Tumor necrosis was considered to be complete when no foci of enhancement were seen within the tumor and at its periphery. RESULTS Complete necrosis was achieved in all lesions regardless of tumor size or morphology. There have been no local recurrences in small and intermediate-sized lesions regardless of tumor morphology during a mean follow-up of 12.5 months. In large HCCs, nodular lesions showed no recurrence, but two of six of nonnodular lesions recurred beyond the thermal lesions created around the tumor. The estimated 1-year survival rate was 98.0% in all patients. CONCLUSIONS This combined therapy has a therapeutic effect on small and intermediate-sized HCCs regardless of tumor morphology and is a promising treatment option for large nodular lesions. Control of large nonnodular lesions is still a challenging problem.

Changes in False Lumen After Transluminal Stent-Graft Placement in Aortic Dissections Six Years’ Experience

Background—Transluminal stent-graft placements (TSGPs) are a new, less invasive procedure now recognized as the choice for aortic disease repair. Treatment of aortic dissections with TSGPs has resulted in good early results, but the long-term results and changes in the false lumen have not been elucidated in detail. Methods and Results—TSGPs were performed in 49 patients with primary tears in their descending aortas, and the follow-up period ranged from 4 months to 6 years. The patients were divided into 32 acute-onset and 17 chronic dissections; of the acute-onset cases, there were 15 Stanford type A retrograde dissections. Periodic enhanced spiral CT was conducted after TSGP. The false lumen in the ascending aorta in 14 (93%) of the Stanford type A cases was obliterated completely within 3 months. The CT study was continued for >2 years for 17 acute-onset dissection and 11 chronic dissection patients. The average false lumen diameters of the proximal, middle, and distal descending aorta before treatment were 15.9, 16.2, and 15.6 mm in the acute-onset dissection group and 28.1, 25.2, and 21.0 mm in the chronic dissection group, respectively. The false lumen diameters 2 years after treatment were 3.0, 3.7, and 3.1 mm in the acute-onset dissection group and 10.6, 10.5, and 11.9 mm in the chronic dissection group, respectively. Two years after TSGPs, the false lumen of the thoracic aorta totally disappeared in 76% of the acute-onset dissection group and 36% of the chronic dissection group. No cases showed rupture after TSGP. Conclusions—Complete obliteration of the false lumen is more likely in acute-onset cases than in chronic cases.

Radiofrequency Ablation Combined with Bone Cement Injection for the Treatment of Bone Malignancies

PURPOSE To evaluate the feasibility, safety, and effectiveness of combined treatment with radiofrequency (RF) ablation followed by bone cement injection in patients with malignant bone neoplasms. MATERIALS AND METHODS Seventeen patients with 23 bone tumors were treated. The tumors, measuring 1.2-15 cm (mean, 4.9 +/- 3.5 cm), were located in the spine (n = 17), iliac bone (n = 3), sacrum (n = 2), and ischial bone (n = 1). All procedures were performed with computed tomographic (CT) fluoroscopic guidance. An electrode with an internally cooled tip was placed in the bone tumor through a biopsy needle and RF energy was applied, followed by cement injection. Pain relief was evaluated with use of the visual analogue scale score (VAS score). Local therapeutic effects were evaluated by contrast-enhanced MR imaging. Lack of tumor enhancement was considered to indicate necrosis. RESULTS The procedures were technically successful in all patients except for one patient with an osteoblastic ischial lesion (22 of 23 patients; 96%). Pain was relieved within 1 week in all 13 patients who reported pain (13 of 13 patients; 100%), with a significant decrease in the VAS score from 8.4 to 1.1 (P <.001). Tumor necrosis was observed in 71% +/- 24% of the tumor volume (range, 14%-100%). Neural damage occurred in four patients in whom the tumor had invaded the posterior cortex of the vertebral body and pedicle. CONCLUSION The combined therapy described here is both feasible and useful for the treatment of malignant bone neoplasms. The safety of the procedure depends on the tumor location. When the tumor is adjacent to the spinal cord, there is a risk of nerve injury.

Superselective Bronchial Artery Embolization for Hemoptysis with a Coaxial Microcatheter System

PURPOSE To compare the effectiveness and safety of superselective bronchial artery embolization with that of nonsuperselective embolization in the control of hemoptysis. MATERIALS AND METHODS Retrospective case analysis was done for 47 patients with hemoptysis originating from a variety of causes. In 22 patients, embolization was performed superselectively using a microcatheter inserted into the bronchial artery beyond the spinal or mediastinal branches (superselective group). In the remaining 25 patients, embolization was performed at the opening of the bronchial artery with a 5-F catheter (nonsuperselective group). RESULTS Initial hemoptysis control rates were 96% (21 of 22) in the superselective group and 88% (22 of 25) in the nonsuperselective group. Cumulative hemoptysis control rates of the superselective and nonsuperselective groups were 80% and 67% at 6 months, 79% and 56% at 1 and 2 years, and 79% and 48% at 3 years, respectively (not significant; generalized Wilcoxon test). One major complication (spinal infarction) occurred in the nonsuperselective group. CONCLUSIONS Superselective embolization is safer and more effective way to control hemoptysis than the ordinary (nonsuperselective) method.

Pulmonary ventilation-perfusion MR imaging in clinical patients.

The purpose of this study was to evaluate the feasibility of comprehensive magnetic resonance (MR) assessment of pulmonary perfusion and ventilation in patients. Both oxygen‐enhanced ventilation MR images and first‐pass contrast‐enhanced perfusion MR images were obtained in 16 patients with lung diseases, including pulmonary embolism, lung malignancy, and bulla. Inversion recovery single‐shot fast spin‐echo images were acquired before and after inhalation of 100% oxygen. The overall success rate of perfusion MR imaging and oxygen‐enhanced MR imaging was 94% and 80%, respectively. All patients with pulmonary embolism showed regional perfusion deficits without ventilation abnormality on ventilation‐perfusion MR imaging. The results of the current study indicate that ventilation‐perfusion MR imaging using oxygen inhalation and bolus injection of MR contrast medium is feasible for comprehensive assessment of pulmonary ventilation‐perfusion abnormalities in patients with lung diseases. J. Magn. Reson. Imaging 2001;14:419–424.

Incidence of Aneurysms in Takayasu's Arteritis:

The angiographic findings of Takayasus arteritis in a series of 113 patients were reviewed. Predominant findings were stenotic or occlusive changes, but fusiform or saccular aneurysms were also found in 36 patients (31.9%) in the various sites of aorta and its major branches. Multiple aneurysms were found in 15 patients. The most common site of aneurysms was the ascending aorta (16 patients); in 7 of the patients these were complicated by aortic regurgitation. Aneurysms developed in the aortic arch in 3 patients, in the descending aorta in 11, in the abdominal aorta in 7, and in the major branches of the aortic arch in 9 patients. In 2 patients, follow-up angiograms showed enlargement of the aneu rysms, and rupture of the aneurysm occurred in 1 patient. Aneuryms were found even in young patients. A fifteen-year-old female showed a huge aneurysm in the ascending aorta as the initial manifestation of this disease. Thickening of the walls of aneurysms was common and characteristic. This study revealed the moderately high incidence of aneurysms of various sites of arteries in patients with Takayasus arteritis. The authors conclude that aneurysm, as well as occlusive changes, can be a primary lesion.

Percutaneous radiofrequency ablation of liver neoplasms adjacent to the gastrointestinal tract after balloon catheter interposition.

A hepatocellular carcinoma compressing the duodenum and a metastatic liver tumor adherent to the stomach were treated by radiofrequency ablation after a balloon was percutaneously placed between the tumor and the gastrointestinal tract to avoid bowel perforation. Neither tumor showed enhancement on dynamic contrast material-enhanced CT after radiofrequency ablation. There were no complications related to the procedures.

Soft-tissue tumors evaluated by line-scan diffusion-weighted imaging: influence of myxoid matrix on the apparent diffusion coefficient.

To compare the apparent diffusion coefficients (ADCs) of myxoid and nonmyxoid soft‐tissue tumors using line‐scan diffusion‐weighted imaging (LSDWI), and to investigate the myxoid matrix influence on ADCs of soft‐tissue tumors.