Nam Kyu Chang

Tracking of Neural Stem Cells in Rats with Intracerebral Hemorrhage by the Use of 3T MRI

Objective To access the feasibility of clinically available 3T MRI to detect the migration of labeled neural stem cells (NSCs) in intracerebral hemorrhage (ICH) in a rat model. Materials and Methods The ethics committee of our institution approved this study. ICH was induced by the injection of collagenase type IV into the right striatum of ten Sprague-Dawley rats. Human NSCs conjugated with Feridex (super-paramagnetic iron oxide: SPIO) were transplanted into the left striatum one week after ICH induction. MRI was performed on a 3T scanner during the first, second, third, fourth, and sixth weeks post-transplantation. MRI was obtained using coronal T2- and T2*-weighted sequences. Two rats were sacrificed every week after in vivo MRI in order to analyze the histological findings. Results ICH in the right striatum was detected by MRI one and two weeks after transplantation without migration of the NSCs. There was no migration of the NSCs as seen on the histological findings one week after transplantation. The histological findings two weeks after transplantation showed a small number of NSCs along the corpus callosum. On MRI three weeks after transplantation, there was a hypointense line along the corpus callosum and decreased signal intensity in the right periventricular region. Histological findings three weeks after transplantation confirmed the presence of the hypointense line representing SPIO-labeled NSCs. MRI four and six weeks after transplantation showed a hypointense spot in the right periventricular region. The histological findings four and six weeks after transplantation showed the presence of prominent NSCs in the right periventricular region. Conclusion 3T MRI can detect the migration of NSCs in rats with ICH along the corpus callosum. Therefore, 3T MRI could be feasible for detecting the migration of NSCs in the clinical setting of stem cell therapy.

Perfusion CT in Colorectal Cancer: Comparison of Perfusion Parameters with Tumor Grade and Microvessel Density

OBJECTIVE The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC. MATERIALS AND METHODS Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearsons correlation analysis was used to correlate CT perfusion parameters with MVD. RESULTS In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD. CONCLUSION BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs. However, perfusion CT is limited in distinguishing well differentiated and poorly differentiated CRCs. Pre-operative perfusion CT does not reflect the MVD of CRCs.

Diagnosis of acute gastrointestinal bleeding: comparison of the arterial, the portal, and the combined set using 64-section computed tomography.

Objectives: To compare the respective capabilities of the arterial, the portal, and the combined set in the detection and localization of acute gastrointestinal (GI) bleeding with 64-section computed tomography (CT). Methods: A total of 46 patients with acute GI bleeding and who had undergone both 64-section CT and digital subtraction angiography were included in this study. The results of angiography were used as a reference standard. Two radiologists independently reviewed the 3 sets of CT images (arterial set, the unenhanced and arterial-phase images; portal set, the unenhanced and portal venous-phase images; combined set, the unenhanced and arterial-phase and portal venous-phase images). The diagnostic accuracy was assessed by a receiver operating characteristic analysis. Results: For each observer, the Az values were 0.915 and 0.931 for the arterial set, 0.903 and 0.933 for the portal set, and 0.919 and 0.911 for the combined set, respectively. The differences were not statistically significant among the 3 data sets for each observer (P > 0.05). Both observers correctly detected the bleeding site in 81.3% and 84.4% on the arterial set, in 81.3% and 84.4% on the portal set, and in 84.4% and 84.4% on the combined set, respectively. Conclusions: Using 64-section CT, the diagnostic performance was not different among the arterial, the portal, and the combined set for the detection and localization of acute GI bleeding.

Selective embolization of the internal iliac arteries for the treatment of intractable hemorrhage in children with malignancies

Purpose Acute internal hemorrhage is an occasionally life-threatening complication in pediatric cancer patients. Many therapeutic approaches have been used to control bleeding with various degrees of success. In this study, we evaluated the efficacy of selective internal iliac artery embolization for controlling acute intractable bleeding in children with malignancies. Methods We retrospectively evaluated the cases of 6 children with various malignancies (acute lymphoblastic leukemia, acute myelogenous leukemia, chronic myelogenous leukemia, T-cell prolymphocytic leukemia, Langerhans cell histiocytosis, and rhabdomyosarcoma), who had undergone selective arterial embolization (SAE) of the internal iliac artery at the Chonnam National University Hwasun Hospital between January 2004 and December 2009. SAE was performed by an interventional radiologist using Gelfoam® and/or Tornado® coils. Results The patients were 5 boys and 1 girl with median age of 6.9 years (range, 0.7-14.8 years) at the time of SAE. SAE was performed once in 4 patients and twice in 2, and the procedure was unilateral in 2 and bilateral in 4. The causes of hemorrhage were as follows: hemorrhagic cystitis (HC) in 3 patients, procedure-related internal iliac artery injuries in 2 patients, and tumor rupture in 1 patient. Initial attempt at conservative management was unsuccessful. Of the 6 patients, 5 (83.3%) showed improvement after SAE without complications. Conclusion SAE may be a safe and effective procedure for controlling acute intractable hemorrhage in pediatric malignancy patients. This procedure may obviate the need for surgery, which carries an attendant risk of morbidity and mortality in cancer patients with critical conditions.

Effect of Ultrasound-Guided Radiofrequency Ablation in Incompletely Treated Hepatocellular Carcinoma after Transcatheter Arterial Chemoembolization

Objective To evaluate the effectiveness of ultrasound-guided radiofrequency (RF) ablation in patients with incompletely treated hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) and to evaluate possible prognostic factors for this therapy. Subjects and Methods Thirty nine patients with incompletely treated single HCC (≤ 5 cm) after TACE were treated with RF ablation. All patients were evaluated for complete tumor ablation rate, local recurrence-free rate, overall survival rate, and complications. Local recurrence-free rate and overall survival rate were calculated using the Kaplan-Meier method. The possible prognostic factors of local recurrence-free rate and survival rate were analyzed using Cox proportional-hazards regression model. Results The complete tumor ablation rate was 92.3%. Local recurrence-free rates for 1-, 2-, 3-, and 5-years were 81.7%, 63.1%, 53.6%, and 35.7%, respectively. One-, 2-, 3-, and 5-year overall survival rates were 96.9%, 82.9%, 67.8%, and 48.4%, respectively. Among prognostic factors included in the analysis, only tumor diameter (≤ 2 cm versus > 2 cm) was statistically significant in terms of predicting local recurrence. Complications were observed in two patients, one with liver abscess and the other with portal venous thrombosis. Conclusion Ultrasound-guided RF ablation could be effective and safe in treating incompletely treated HCC after TACE. The diameter of HCC was a significant prognostic factor for local recurrence.

Myeloid Sarcoma of the Breast Mimicking Hamartoma on Sonography

Myeloid sarcoma, also known as granulocytic sarcoma, chloroma, and extramedullary myeloblastoma, is a neoplasm of myeloblasts or immature myeloid cells that occurs at an extramedullary site. Although these tumors can involve any part of the body, common sites of involvement are bone, periosteum, lymph nodes, skin, and soft tissue. 1 Myeloid sarcoma involving the breast is uncommon. To our knowledge, there have been a few reports on sonographic findings of myeloid sarcoma of the breast in patients with acute myeloid leukemia. Although the sonographic findings that have been reported are not specific for myeloid sarcoma, there were suspicious findings of irregular hypoechoic masses in previous reports. 2-6 We report a case of myeloid sarcoma involving the breast with radiologic findings mimicking hamartoma on sonography.

Retrograde Tempofilter II™ Placement within the Superior Vena Cava in a Patient with Acute Upper Extremity Deep Venous Thrombosis: the Filter Stands on Its Head

The Tempofilter II is a widely used temporary vena cava filter. Its unique design, which includes a long tethering catheter with a subcutaneous anchor, facilitates the deployment and retrieval of the device. Despite this, the Tempofilter II has been used only in the inferior vena cava of patients with lower extremity deep venous thrombosis. In this article, we present a case of superior vena cava filtering using the Tempofilter II in patients with upper extremity deep venous thrombosis.

Fracture of a Tempofilter II: an Initial Case Report

Tempofilter II is a device that is used for pulmonary embolism prophylaxis. Since the appearance of the Tempofilter II following withdrawal of the Tempofilter I, it has been reported that the Tempofilter II is safe, effective and useful. Here we report on the first case of a fracture of one leg of the filter and this leg was embedded in the inferior vena cava wall in a 62-year-old man with deep vein thrombosis.