Metformin Ameliorates Lipotoxic β-Cell Dysfunction through a Concentration-Dependent Dual Mechanism of Action

BACKGROUND: Chronic exposure to elevated levels of free fatty acids contributes to pancreatic β-cell dysfunction. Although it is well known that metformin induces cellular energy depletion and a concomitant activation of AMP-activated protein kinase (AMPK) through inhibition of the respiratory chain, previous studies have shown inconsistent results with regard to the action of metformin on pancreatic β-cells. We therefore examined the effects of metformin on pancreatic β-cells under lipotoxic stress.METHODS: NIT-1 cells and mouse islets were exposed to palmitate and treated with 0.05 and 0.5 mM metformin. Cell viability, glucose-stimulated insulin secretion, cellular adenosine triphosphate, reactive oxygen species (ROS) levels and Rho kinase (ROCK) activities were measured. The phosphorylation of AMPK was evaluated by Western blot analysis and mRNA levels of endoplasmic reticulum (ER) stress markers and NADPH oxidase (NOX) were measured by real-time quantitative polymerase chain reaction analysis.RESULTS: We found that metformin has protective effects on palmitate-induced β-cell dysfunction. Metformin at a concentration of 0.05 mM inhibits NOX and suppresses the palmitate-induced elevation of ER stress markers and ROS levels in a AMPK-independent manner, whereas 0.5 mM metformin inhibits ROCK activity and activates AMPK.CONCLUSION: This study suggests that the action of metformin on β-cell lipotoxicity was implemented by different molecular pathways depending on its concentration. Metformin at a usual therapeutic dose is supposed to alleviate lipotoxic β-cell dysfunction through inhibition of oxidative stress and ER stress.

Evaluation of Engraftment of Superparamagnetic Iron Oxide-Labeled Mesenchymal Stem Cells Using Three-Dimensional Reconstruction of Magnetic Resonance Imaging in Photothrombotic Cerebral Infarction Models of Rats

OBJECTIVE: To evaluate engraftment by visualizing the location of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) three-dimensionally in photothrombotic cerebral infarction (PTCI) models of rats. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) of an agarose block containing superparamagnetic iron oxide (SPIO)-labeled hBM-MSCs was performed using a 3.0-T MRI, T2-(T2WI), T2*-(T2*WI), and susceptibility-weighted images (SWI). PTCI was induced in 6 rats, and 2.5 x 10(5) SPIO-labeled hBM-MSCs were infused through the ipsilateral internal carotid artery (ICA group) or tail vein (IV group). MRI was performed on days 1, 3, 7, and 14 after stem cell injection. Dark signal regions were confirmed using histology. Three-dimensional MRI reconstruction was performed using the clinical workflow solution to evaluate the engraftment of hBM-MSCs. Volumetric analysis of the engraftment was also performed. RESULTS: The volumes of SPIO-labeled hBM-MSCs in the phantom MRI were 129.3, 68.4, and 25.9 microL using SWI, T2*WI, and T2WI, respectively. SPIO-labeled hBM-MSCs appeared on day 1 after injection, encircling the cerebral infarction from the ventral side. Dark signal regions matched iron positive cells and human origin (positive) cells. The volume of the engraftment was larger in the ICA group on days 1, 3, and 7, after stem cell injection (p < 0.05 on SWI). SWI was the most sensitive MRI pulse sequence (p < 0.05). The volume of infarction decreased until day 14. CONCLUSION: The engraftment of SPIO-labeled hBM-MSCs can be visualized and evaluated three-dimensionally in PTCI models of rats. The engraftment volume was larger in the ICA group than IV group on early stage within one week.

Engraftment of Human Mesenchymal Stem Cells in a Rat Photothrombotic Cerebral Infarction Model : Comparison of Intra-Arterial and Intravenous Infusion Using MRI and Histological Analysis

OBJECTIVE: This study aimed to evaluate the hypotheses that administration routes [intra-arterial (IA) vs. intravenous (IV)] affect the early stage migration of transplanted human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in acute brain infarction. METHODS: Male Sprague-Dawley rats (n=40) were subjected to photothrombotic infarction. Three days after photothrombotic infarction, rats were randomly allocated to one of four experimental groups [IA group : n=12, IV group : n=12, superparamagnetic iron oxide (SPIO) group : n=8, control group : n=8]. All groups were subdivided into 1, 6, 24, and 48 hours groups according to time point of sacrifice. Magnetic resonance imaging (MRI) consisting of T2 weighted image (T2WI), T2* weighted image (T2*WI), susceptibility weighted image (SWI), and diffusion weighted image of rat brain were obtained prior to and at 1, 6, 24, and 48 hours post-implantation. After final MRI, rats were sacrificed and grafted cells were analyzed in brain and lung specimen using Prussian blue and immunohistochemical staining. RESULTS: Grafted cells appeared as dark signal intensity regions at the peri-lesional zone. In IA group, dark signals in peri-lesional zone were more prominent compared with IV group. SWI showed largest dark signal followed by T2*WI and T2WI in both IA and IV groups. On Prussian blue staining, IA administration showed substantially increased migration and a large number of transplanted hBM-MSCs in the target brain than IV administration. The Prussian blue-positive cells were not detected in SPIO and control groups. CONCLUSION: In a rat photothrombotic model of ischemic stroke, selective IA administration of human mesenchymal stem cells is more effective than IV administration. MRI and histological analyses revealed the time course of cell migration, and the numbers and distribution of hBM-MSCs delivered into the brain.

In vivo Tracking of Mesenchymal Stem Cells Labeled with a Novel Chitosan-coated Superparamagnetic Iron Oxide Nanoparticles using 3.0T MRI

This study aimed to characterize and MRI track the mesenchymal stem cells labeled with chitosan-coated superparamagnetic iron oxide (Chitosan-SPIO). Chitosan-SPIO was synthesized from a mixture of FeCl2 and FeCl3. The human bone marrow derived mesenchymal stem cells (hBM-MSC) were labeled with 50 microg Fe/mL chitosan-SPIO and Resovist. The labeling efficiency was assessed by iron content, Prussian blue staining, electron microscopy and in vitro MR imaging. The labeled cells were also analyzed for cytotoxicity, phenotype and differentiation potential. Electron microscopic observations and Prussian blue staining revealed 100% of cells were labeled with iron particles. MR imaging was able to detect the labeled MSC successfully. Chitosan-SPIO did not show any cytotoxicity up to 200 microgram Fe/mL concentration. The labeled stem cells did not exhibit any significant alterations in the surface markers expression or adipo/osteo/chondrogenic differentiation potential when compared to unlabeled control cells. After contralateral injection into rabbit ischemic brain, the iron labeled stem cells were tracked by periodical in vivo MR images. The migration of cells was also confirmed by histological studies. The novel chitosan-SPIO enables to label and track MSC for in vivo MRI without cellular alteration.

Transcatheter Arterial Embolization in Patients with Kidney Diseases: an Overview of the Technical Aspects and Clinical Indications

Therapeutic embolization is defined as the voluntary occlusion of one or several vessels, and this is achieved by inserting material into the lumen to obtain transient or permanent thrombosis in the downstream vascular bed. There are a number of indications for this approach in urological practice, in particular for the patients with parenchymatous or vascular kidney disease. In this review, we present the different embolization techniques and the principally employed occluding agents, and then we present the principal clinical indications and we discuss other pathologies that may benefit from this non-invasive therapy. The complications, side effects and main precautions associated with this approach are also described.

Contrast Extravasation into an Acute Spontaneous Intracerebral Hematoma: Multidetector CT Angiographic Findings and Clinical Implications

PURPOSE: The purpose of this study was to evaluate multidetector row CT (MDCT) angiographic findings and their clinical significance for contrast extravasation into a spontaneous intracerebral hematoma (ICH). MATERIALS AND METHODS: MDCT angiographic studies and clinical records of 115 patients with spontaneous ICH were retrospectively reviewed. Cases were divided into two groups according to the presence or absence of contrast extravasation. The cases in the two groups were compared to determine the differences in radiological and clinical findings. The contrast extravasation group was divided into two subgroups according to radiological findings as follows: single or multiple dot-like contrast extravasation (Type A) and beaded-tubular (with or without dot-like extravasation) contrast extravasation (Type B). RESULTS: Contrast extravasation was seen in 38 patients (33%). It was associated with a larger hematoma volume, more frequent intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH), a shorter time interval from onset to the time of the CT scan, lower Glasgow coma scale (GCS), and a higher mortality rate. Type A and B contrast extravasation were observed in 16 (42%) and 22 (58%) patients, respectively. The rate of IVH and the clinical outcome of patients with Type B showed a significant correlation. CONCLUSION: Two types of contrast extravasation into an ICH show a significant difference in the rate of IVH and in clinical outcome. Detecting the presence of contrast extravasation and classifying them according to the morphologic patterns are important in predicting a prognosis.

Comparison of the CT and Pathologic Findings of Pulmonary Fat Embolism Induced by Triolein and Oleic Acid in Rabbits

PURPOSE: The aim of this study was to evaluate the CT findings of pulmonary fat embolism syndrome that was induced by triolein and oleic acid, along with its pathologic correlation. MATERIALS AND METHODS: 16 rabbits were included in this study. The rabbits in group I (n=8) were embolized with 0.2 mL triolein and the rabbits of group II (n=8) were embolized with 0.2 mL oleic acid through ear veins. HRCT scans were done prior to embolization and at 0.5, 4, 24, 48 and 72 hours post-embolization. The pathologic correlations were determined at 0.5, 24, 48 and 72 hours. RESULTS: At 24 hours, one group I rabbit showed abnormal CT findings that were composed of several 2-3 mm nodules and multiple ill-defined peripheral ground glass opacities. The pathologic finding of this rabbit at 48 hours was mainly intraarveolar edema. All the group II rabbits (n=8/8) showed ill-defined bilateral and peripheral ground glass opacities with (n=6/8) or without consolidations (n=2/8) on the 0.5 hour CT. All the rabbits (n=7/7) showed that the new ground glass opacities and ground glass opacities noted on the 0.5 hour CT were changed into consolidation. The margins of the ground glass opacities and consolidations were more sharpened on the 24 hours CT. All 6 rabbits (n=6/6) showed consolidations without ground glass opacities and the margins of the consolidations were more sharpened on the 48 hours CT. There was no significant interval change on the 72 hours CT. The pathologic findings of ground glass opacities were interstitial edema or mild intraalveolar edema. The pathologic findings of consolidation were intraalveolar edema, hemorrhage and coagulation necrosis. CONCLUSION: The CT findings after fat embolization using triolein and oleic acid were ill-defined peripheral ground glass opacities with/without consolidations. These findings occurred in only one triolein group with the time lag, but these findings were immediately and extensively seen in all group II rabbits. These CT findings may be important for making a diagnosis of pulmonary fat embolism syndrome.

Ultrasound-Guided Radiofrequency Ablation of Thyroid Gland: A Preliminary Study in Dogs

PURPOSE: The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. MATERIALS AND METHODS: Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. RESULTS: The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4+/-0.5 mm in group I and 11.4+/-0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal wall. In summary, the radiofrequency ablation therapy for the benign or malignant thyroid nodules located in anterior aspect (within a 5 mm radius) of the thyroid gland in human suggests this is an effective treatment, through this was an animal study performed on dogs.

Fixation Methods for Implantable Port Chamber: Comparative Study Using Glue, Self-stabilizing Leg and Suture Fixations in Rabbits

OBJECTIVE: To evaluate the fixation strength and tissue reaction of the glue fixation and self-stabilizing leg fixation methods and to compare the results with those of the conventional tagging suture fixation method. MATER AND METHODS: Twelve healthy rabbits were selected and three different methods of implanting the port chamber were employed on the back of each rabbit. A total of thirty six port chambers were implanted with these three different methods, viz. the glue fixation method using tissue adhesive, the self-stabilizing leg method using a self-expandable stabilizing leg, and the suture fixation method. The fixation strength and the gross and histopathologic changes of each fixation method were evaluated at three days, one week, two weeks and four weeks after port implantation. RESULTS: The glue fixation method showed a good fixation strength, which was similar to that of the tagging suture method (p=0.3486). Five of the six ports (83%) implanted with the glue fixation method which were examined after two weeks showed cracks on the external surface, but this had no adverse effects on their function. A large amount of granulation tissue reaction was found at the bottom of the chamber (p=0.0025). The fixation with the self-stabilizing leg showed relatively lower fixation strength (p=0.0043), but no turning-over of the chamber occurred. The fixation strength improved with time after the first week, and minimal granulation tissue reaction was observed with this method. CONCLUSION: The glue fixation method exhibited equal fixation strength compared to the suture fixation, but showed cracking and a large amount of granulation tissue, whereas the fixation with a self-stabilizing leg showed weaker fixation strength.

Hepatic CT Enhancement: Comparison between Dimeric and Monomeric Nonionic Contrast Agents in Rabbits

PURPOSE: To determine the hepatic and vascular enhancement profiles with nonionic dimeric, iodixanol, contrast agent in the rabbit and to compare them with nonionic monomeric, ioversol, contrast agent. MATERIALS AND METHODS: Seven rabbits initially underwent hepatic dynamic CT scan with either iodixanol or ioversol, followed by repeated CT scan with other unused contrast agent with one week interval between scans. Pre and post contrast attenuation values of hepatic parenchyma, aorta and portal vein were measured sequentially. The mean enhancement of the hepatic parenchyma, aorta and portal vein were compared between two agents. The mean peak enhancement and peak enhancement time of the liver, aorta, and portal vein were also compared. RESULTS: The attenuation values of ioversol showed a greater mean hepatic enhancement than iodixanol from 18 seconds to 39 seconds after injection (from late arterial phase to early portal venous phase) with a statistical significance (p<0.05). The mean peak enhancement of hepatic parenchyma, aorta and portal vein was also greater using ioversol than iodixanol, but the mean peak enhancement times of ioversol and iodixanol were nearly identical. CONCLUSION: Ioversol may have the greater effects than iodixanol on hepatic tumor conspicuity, especially from late arterial phase to early portal veneous phase.

A Comparative Study of Intra-arterial and Intramuscular Administration of phVEGF165 in a Chronic Ischemic Model of Rabbit Hindlimb

PURPOSE: To obtain phVEGF165 for angiogenesis and to compare the effects of its intra-arterial and intramuscular administration in a chronic ischemic rabbit hindimb model. MATERIALS AND METHODS: Chronic ischemic models were constructed in the left hindlimb of rabbits and divided into control (n=6), intra-arterial (n=7) and intramuscular groups (n=5). Plasmid DNA (phVEGF165) expressing vascular endothelial growth factor (VEGF) was obtained from HL60 cells, and transfection into CHO cells and western blot analysis of the medium, as well as proliferation assay of CPAE cells were performed. Two weeks after construction of the models, 500 mug phVEGF165 was injected into both the left common iliac artery and thigh muscles. Angiography was performed and the number of vessels counted, and ELISA was used to determine the quantity of VEGF in blood samples. Wilcoxon signed rank test was employed for statistical analysis. RESULTS: VEGF165 was expressed on western blot of the culture medium. Proliferation assay showed that optical densities were 0.73+/-0.043 in the control study and 1.09+/-0.015 in phVEGF165. The angiographic scores were 1.32+/-0.13 (pre-gene therapy) and 1.30+/-0.07 (post-gene therapy) in the control group, 1.42+/-0.15 and 1.59+/-0.09 in the intra-arterial group, 1.59+/-0.27 and 1.14+/-0.12 in the intramuscular group. The differences were not statistically significant. In the intra-arterial group, serum VEGF levels were 39.96+/-1.08 pg/ml (pregene therapy), 44.99+/-2.13 pg/ml (4th day), 48.18+/-1.49 pg/ml (1st week), 45.70+/-3.77 pg/ml (2nd week), and 46.54+/-5.47 pg/ml (3rd week), but in the control and intramuscular groups there were no increases. CONCLUSION: phVEGF165 affected the proliferation of CPAE cells. There was no difference in angiographic scores and serum VEGF levels between intra-arterial and intramuscular administrations.

Radial Artery Approach for Transcatheter Arterial Chemoembolization in Patients with Hepatocellular Carcinoma

PURPOSE: To evaluate the feasibility and usefulness of the transradial approach for intra-arterial chemoembolization therapy in patients with hepatocellular carcinomas. MATERIALS AND METHODS: Twenty-nine patients with hepatocellular carcinoma who underwent intra-arterial chemoembolization via the radial artery approach were involved in this study. All underwent Allen's test to check ulnar arterial patency. In all cases, we used the radial approach hepatic artery (RHA) catheter designed by ourselves, evaluating the selection ability of the hepatic artery using an RHA cathter, the number of punctures, the procedure time, and compression time at the puncture site as well as complications occurring during and after the procedure. RESULTS: Except for three in which puncture failure, brachial artery variation or hepatic artery variation occurred, all procedures were successful. The mean number of punctures was 3.5, and the average duration of the whole procedure was one and half hours. This gradually decreased as the number of procedures increased. The average duration at a compression of puncture site was 12 minutes. There were no major complications. Minor complications included minimal intimal dissection of the radial artery (3.8%), reversible vasospasm of the radial artery (7.7%), hematoma at a puncture site (7.7%) and transient neurologic deficit (3.8%). CONCLUSION: The transradial approach using an RHA catheter for intra-arterial chemoembolization therapy in patients with hepatocellular carcinomas was technically feasible, with acceptable levels of safety. It may be a good alternative to absolute bed rest with a sand bag after the femoral approach.

An experimental model of ischemia in rabbit hindlimb

This study was performed to establish an experimental model of ischemia for the investigation of new treatment modality of limb-threatening ischemia. We produced ischemia in the hindlimbs of 8 New Zealand white rabbits. Under general anesthesia, the left femoral artery was exposed, freed, and excised from distal external iliac artery to proximal popliteal and saphenous arteries. And then both hindlimbs were serially examined to assess the ischemia according to the time table until postoperative 6 weeks. We assessed clinical observation, blood pressure, radioisotopic perfusion scan, and angiography. Clinical ischemic changes of the operated feet were observed in 63%. The blood pressure of left calves was measurable on postoperative day 3 (p<0.05, vs preoperative day 2) and then gradually increased to reach a plateau in postoperative week 6. Radioisotopic arterial perfusion showed similar profiles as in blood pressure. Angiography of ischemic hindlimbs demonstrated a few collateral vessels arising from the internal iliac artery with the reconstitution of the posterior tibial artery in postoperative week 2. In postoperative week 6, collaterals remained the same in number. However, these became dilated and tortuous and showed reconstitution in distal hindleg. In conclusion, this is a reproducible, measurable, and economical animal model of hind limb ischemia.

Development of the Single Nodular VX-2 Carcinoma Model in Rabbit Liver: Tissue Chip Implantation under Ultrasonographic Guidance

PURPOSE: To implant tissue chips in New Zealand rabbits, and thus redurce the frequency with which scattered VX2 carcinoma nodules and early metastasis develop in these animals. MATERIALS AND METHODS: VX2-carcinoma tissue chips of two different sizes were implanted under ultrasonographic guidance. In each of 12 New Zealand rabbits (group 1), there 1-mm tissue chips were implanted in the liver using an 18-gauge needle, and in the same way, one 3-mm chip with an added gelfoam pellet was implanted in the proximal lumen of the liver of each of ten other New Zealand rabbits (group 2). Three weeks after implantation, the animals underwent dvalphase CT scanning and were sacrificed, and the Number and size of tumor nodules, and metastasis were evaluated either macro-or microscopically. RESULTS: In ten rabbits in group I, a total of 21 nodules (16 in the liver, 5 in the peritoneal wall) were observed, which in nine rabbits in group 2, a total of ten nodules-all in the liver-were present. CT scans depicted tumor nodules in 50% of group-I rabbits, and in 29% those in group 2. Mean tumor diameter was 12 +/-9 mm in group 1 and 6.4 +/-3 mm in group 2. Histologic examination indicated the presence of nodular VX2 carcinoma, with varying degrees of central necrosis, a feature more prominent in group 2. CONCLUSION: To provide a well-localized tumor nodule in rabbit liver, tissue chip implantation of VX2 carcinoma, especially with added gelfoam, is a good alternative to intraparenchymal injection of tumor suspension.

Correlation of VEGF with contrast enhancement on dual-phase dynamic helical CT in liver tumors: preliminary study

The purpose of this preliminary study is to elucidate that vascular endothelial growth factor (VEGF) influences contrast enhancement of hepatic tumors on computed tomography (CT). Fourteen patients with hepatic tumors (11 hepatocellular carcinomas; 3 metastatic cancers) underwent a dual-phase dynamic helical CT or computed tomographic hepatic arteriography. The attenuation of each mass was determined as hyperattenuation, isoattenuation or hypoattenuation with respect to the adjacent nontumorous parenchyma. Gun-needle biopsy was done for each tumor, and paraffin sections were immunostained with anti- VEGF antibody by the avidin-biotin-peroxidase complex method. The pathologic grade was made by intensity (1 +, 2+, 3+) and area (+/-, 1 +, 2+). The tumor ranged 2.0-14.0 cm in size (mean, 5.8 cm). In arterial phase, the intensity was not correlated with the degree of enhancement (p=0.086). However, the correlation between the attenuation value of hepatic arterial phase and the area of positive tumor cells was statistically significant (p=0.002). VEGF may be the factor that enhances the hepatic mass with water-soluble iodinated contrast agent in CT.

A Case of Obstructive Renal Cndidiasis Treated with Percutaneous Nephrostomy in Prematurity

The improved survival rate of premature infants requiring intensive care, shows an increased risk for nosocomial infections such as disseminated fungal infection. Renal candidasis usually occurs secondary to systemic disease, and can Iead to obstructive uropathy by fungus ball. A male neonate was born in week 28 of the gestational period. His birth weight was 1200gm. He required mechanical ventilation and surfactant for respiratory distress syndrome, umbilical artery and vein catheterization, percutaneous central veneous catheterization(PCVC) for parenteral nutrition, steroid, aminophylline and broad spectrum anibiotics. Hypertension developed on the 29th hospital day, but was not controlled by diuretics and antihypertensive drugs. on the 40th hospital day, he had abdominal distension, anuria, and azotemia. A Renal ultrasonogram showed that the ureteropelvic junction of the left kidney was completely obstructed with fungus balls. A percutaneous nephrostorny tube, made in a pigtail shape by hand, was inserted under fluoroscopy guidance, and the obstruction of the pelvis was resolved by wire manipulation. Parenteral amphotericin B and oral flucytocine were started, and the left renal pelvis was directly drained and irrigated by percutaneous nephrostomy tube. Candida albicans(C. albicuns) was cultured from urine and a percutaneous central venous catheter tip. His general condition improved, and follow up urine culture revealed no fungus. On follow-up renal ultrasonogram, renal cortex echogenicity and fungus ball had disappeared except for mild left renal calyectasis and pelvic thickening. This report describes a case of obstructive uropathy by fungus ball in systemic candidiasis of prematurity, and reviews the related literature.

Tuberculous Aneurysm of the Abdominal Aorta: Endovascular Repair Using Stent Grafts in Two Cases

Tuberculous aneurysm of the aorta is exceedingly rare. To date, the standard therapy for mycotic aneurysm of the abdominal aorta has been surgery involving in-situ graft placement or extra-anatomic bypass surgery followed by effective anti-tuberculous medication. Only recently has the use of a stent graft in the treat-ment of tuberculous aortic aneurysm been described in the literature. We report two cases in which a tuberculous aneurysm of the abdominal aorta was success-fully repaired using endovascular stent grafts. One case involved is a 42-year-old woman with a large suprarenal abdominal aortic aneurysm and a right psoas abscess, and the other, a 41-year-old man in whom an abdominal aortic aneurysm ruptured during surgical drainage of a psoas abscess.

Optimal Scan Time of Dual-phase Spiral CT in Normal Rabbit Liver: Effect of Contrast Injection Rate

PURPOSE: To determine the effect of contrast injection rate on rabbit liver enhancement and the optimaltem-poral window for dual-phase spiral CT of rabbit liver at each injection rate. MATERIALS AND METHODS: Usingspiral CT, seven New Zealand White rabbits underwent dynamic scanning at one level of liver. Three protocols ofcontrast injection rates were employed, namely 0.3 ml/sec(group 1), 1ml/sec(group 2) and 2 ml/sec(group 3). During120 seconds of total scan time, the scan interval was 3 seconds. Densities of the aorta, liver and portal veinwere averaged in equivalent time. The different injection rate protocols were compared for peak enhancement/timeon a time density curve. RESULTS: Mean peak enhancement (HU) in equivalent time(secs) was 310/18(group 1),383/9(group 2) and 357/6(group 3) in the aorta ; 34/36, 40/36 and 41/30 in the liver ; and 135/36, 153/24 and170/21 in the portal vein. The temporal window during the arterial phase was 12-21 sec(group 1), 6-12 sec(group2), and 6-12 sec(group 3). The temporal window during the portal phase was from 30 sec(0.3ml/sec), 21sec(1ml/sec)and 21 sec(2 ml/sec). CONCLUSION: During dual-phase spiral CT, the temporal window for liver scanningshould be determined according to each contrast injection rate. A slow contrast injection rate prolongs thetemporal window during the arterial phase.

Helical CT of a Tracheobronchial Phantom: Angle and Optimal Window Affecting Size Measurements of ThreeDimensional Images

PURPOSE: To determine the effect of angle variation, relative to scan plan and optimal window setting, on thesize of three dimensional spiral CT images of a tracheobronchial tree using a phantom. MATERIALS AND METHODS:Spiral CT[collimation(mm)/table speed(mm/sec): 3/3; reconstruction interval:1.5 mm] was performed on atracheobronchial phantom consisting of a box filled with saline solution containing air-filled 5cc syringesoriented at varying angles relative to the scan plan. The diameter of three dimensional images was measured ateach window(minimal threshold value; -1000 HU; maximaml threshold value: from -300 HU to -500 HU; 50 HU interval). RESULTS: The inner diamenter of syringes used for tracheobronchial phantom was 12.55 +/-3.19mm. At all windows,as the angle became more perpendicular, the diameter of three-dimensional images increased, and at all angles, asmaxinal HU increased, measured diameter also increased(p<0.0001). In particular, at a maximal value of -500HU,measured values were closest to control values at all angles. CONCLUSION: Diameter can be measured close tocontrol value from three dimensional spiral CT images at maximal HU of -500 window, regardless of angle.

Intra-arterial Port Implantation for Intra-arterial Chemotherapy: Comparison between PIPS(Pe rcutaneouslyImplantable Port System) and Port System

PURPOSE: To compare the techniques and complications of intra-arterial port implantation for intra-arterialchemotherapy between PIPS and the port system. MATERIALS AND METHODS: For intra-arterial port implantation, 27cases in 27 patients were retrospectively evalu-ated using PIPS(PIPS-200, William Cook Europe, Denmark) while for21 cases in 19 patients a pediatric ve-nous port system(Port-A-Cath, 5.8F, SIMS Deltec, U.S.A.) was used. Allintra-arterial port implantation was performed percuteneously in an angiographic ward. Hepatocellular carcinomawas diagnosed in 18 patients and hepatic metastasis in 16. Peripheral cholangiocarcinoma, and pancreatic gastric,ovarian, renal cell and colon carcinoma were included. We compared the techniques and complications between PIPSand the port system. The follow up period ranged from 23 to 494(mean, 163) days in PIPS and from 12 to 431(mean,150) days in the port system. RESULTS: In all cases, intra-arterial port implantations were technicallysuccessful. Port catheter tips were locat-ed in the common hepatic artery(n=8), proper hepatic artery(n=7), righthepatic artery(n=5), gastroduodenal artery(n=2), left hepatic artery(n=1), pancreaticoduodenal artery(n=1),inferior mesenteric artery(n=1), lum-bar artery(n=1), and renal artery(n=1) in PIPS, and in the proper hepaticartery(n=6), gastroduodenal artery(n=6), common hepatic artery(n=3), right hepatic artery(n=4), inferiormesenteric artery(n=1), and in-ternal iliac artery(n=1) in the port system. Port chambers were buried ininfrainguinal subcutaneous tissue. Using PIPS, complications developed in seven cases(25.9%) and of these, four(57.1%) were catheter or cham-ber related. In the port system, catheter or chamber related complications developedin four cases(19.0%). CONCLUSION: Because PIPS and the port system have relative merits and demetrits, successfulintra-arterial port implantation is possible if equipment is properly selected.