Jeong Min Lee

MR Imaging-Histopathologic Correlation of Radiofrequency Thermal Ablation Lesion in a Rabbit Liver Model: Observation during Acute and Chronic Stages

Objective To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis. Materials and Methods Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MR-pathologic correlation was performed. Results In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination. Conclusion MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.

Hepatic Arterioportal Shunts: Dynamic CT and MR Features

With the increased temporal resolution available in dynamic computed tomography (CT) and magnetic resonance imaging (MRI), hepatic arterioportal shunts are now more frequently encountered than in the past. The condition occurs in various hepatic diseases in which portal or hepatic venous flow is compromised. The underlying mechanism and the degree of shunt affect its appearance at dynamic imaging. The dynamic CT and MRI findings have been summarized as early enhancement of peripheral portal veins, and wedge-shaped transient parenchymal enhancement during the hepatic arterial phase. Recognition of arterioportal shunt can suggest the presence of a previously unsuspected disorder and avoids false-positive diagnosis or overestimation of a hepatic disease. Familiarity with the pathophysiology of arterioportal shunt also allows investigation of the hepatic hemodynamic changes occurring in various hepatic diseases.

Adenomyoma of the small intestine: report of two cases and review of the literature.

Adenomyoma of the small intestine is a rare tumor‐like lesion composed of exocrine‐type ducts and hypertrophic smooth muscle. We describe two cases of adenomyoma of the small intestine. One was an ileal adenomyoma that presented with intussusception occurring in a 7‐month‐old boy. The other was a jejunal adenomyoma found incidentally in a 63‐year‐old man with colon cancer. Histologically, the lesions composed of benign ducts and bundles of smooth muscle. The second case was detected on contrast‐enhanced computed tomography scan as a small enhancing polypoid mass. We review the previous literature of adenomyoma of the small intestine.

Saline-Enhanced Radiofrequency Thermal Ablation of the Lung: A Feasibility Study in Rabbits

Objective To assess the feasibility and safety of CT-guided percutaneous transthoracic radiofrequency ablation (RFA) with saline infusion of pulmonary tissue in rabbits. Materials and Methods Twenty-eight New Zealand White rabbits were divided into two groups: an RFA group (n=10) and a saline-enhanced RFA (SRFA) group (n=18). In the RFA group, percutaneous RFA of the lung was performed under CT guidance and using a 17-gauge internally cooled electrode. In the SRFA group, 1.5 ml of 0.9% saline was infused slowly through a 21-gauge, polyteflon-coated Chiba needle prior to and during RFA. Lesion size and the healing process were studied in rabbits sacrificed at times from the day following treatment to three weeks after, and any complications were noted. Results In the SRFA group, the mean diameter (12.5 ± 1.6 mm) of acute RF lesions was greater than that of RFA lesions (8.5 ± 1.4 mm) (p < .05). The complications arising in 12 cases were pneumothorax (n=8), thermal injury to the chest wall (n=2), hemothorax (n=1), and lung abscess (n=1). Although procedure-related complications tended to occur more frequently in the SRFA group (55.6%) than in the RFA group (20%), the difference was not statistically significant (p = .11). Conclusion Saline-enhanced RFA of pulmonary tissue in rabbits produces more extensive coagulation necrosis than conventional RFA procedures, without adding substantial risk of serious complications.

Treatment of Infected Bulla with Alcohol Sclerosis Combined with Percutaneous Catheter Drainage: A Preliminary Report

Purpose; To evaluate effectiveness of alcohol sclerosis combined with percutaneous catheter drainage (PCD) for treatment of infected bulla. Materials and Methods: Infected bulla in four consecutive patients were treated. In all patients, percutaneous catheter drainage of the bulla was performed . Instillation of sterile alcohol (99% ethano l) was carried out into the cavity of the bulla. Alcohol was left in the cavity for approximately 30 minutes in each session. Alcohol instillation was repeated according to the size of bulla. Patients were subsequently followed up with serial chest radiographs and CT scans. Results: AII patients showed significant improvement both clinically and radiologically. Disappearance of the bulla and reexpansion of surrounding lung parenchyma was observed in two patients and partial resolution (80% reduction in size) was seen in anothertwo patients. Complications included mild chest pain during instillation of alcohol in all patients and delayed radiating shoulder pain in one patient. Conclusion : We provisionally conclude that intracavitary alcohol instillation combined with PCD is effective in thetreatment ofthe infected bulla .