Comparison of Brain Activation in Response to Two Dimensional and Three Dimensional On-Line Games

OBJECTIVE: The present study assessed the difference in the brain activity of professional gamers (excessive players, but not addicts) in response to playing a 3-dimensional online game with an improved interface. METHODS: Twenty-three StarCraft I pro gamers and 16 StarCraft II pro gamers were recruited at Chung Ang University Medical Center. Brain activity in response to StarCraft I or II cues was assessed with a 1.5 Tesla Espree MRI scanner. RESULTS: StarCraft I pro gamers showed significantly greater activity in 4 clusters in response to the video game cues compared to StarCraft II pro gamers: right superior frontal gyrus, right medial frontal gyrus, right occipital lobe, and left medial frontal gyrus. StarCraft II pro gamers showed significantly greater activity in 3 clusters in response to the video game cues compared to StarCraft I pro gamers: left middle frontal gyrus, left temporal fusiform gyrus and left cerebellum. DISCUSSION: This is the first study to show the difference in brain activity between gamers playing either a 2-dimensional or 3-dimensional online game. Current brain imaging studies may confirm the pro gamers' experience when playing StarCraft II, a 3-dimensional game with an improved interface, relative to playing StarCraft I.

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.

Endovascular Treatment for Common Iliac Artery Injury Complicating Lumbar Disc Surgery : Limited Usefulness of Temporary Balloon Occlusion

Vascular injury during lumbar disc surgery is a rare but potentially life-threatening complication. It has been managed by open vascular surgical repair. With recent technologic advance, endovascular treatment became one of effective treatment modalities. We present a case of a 32-year-old woman who suffered with common iliac artery injury during lumbar disc surgery that was treated successfully by endovascular repair with temporary balloon occlusion and subsequent insertion of a covered stent. Temporary balloon occlusion for 1.5 hours could stop bleeding, but growing pseudoaneurysm was identified at the injury site during the following 13 days. It seems that the temporary balloon occlusion can stall bleeding from arterial injury for considerable time duration, but cannot be a single treatment modality and requires subsequent insertion of a covered stent.

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.

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.

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 Clinical Review and Comparative Study of CBD Exploration and Percutaneous Transhepatic Stone Removal for Management in Recurrent Biliary Stone

PURPOSE: Recurrent bile duct stones, following biliary surgery, cause many difficult problems and reoperation on the biliary tract has limitation due to high mortality and morbidity. In recent years, various non-operative modalities for the management of recurrent stone have been developed and reoperation on biliary. This study was designed to determine the factors contributing to the success rate, and to investigate the optimal treatment method, of reccurrent biliary stones. METHODS: Thirty-nine patients, treated by percutaneous transhepatic stone removal (PTBD group), and 42 treated by a common bile duct exploration (operation group), at Chung- Ang University Hospital, between January 1999 and August 2002, were retrospectively analyzed. RESULTS: Complete removal (Success) was achieved in 82.1 and 86.1% of the cases of the PTBD and operation groups, respectively. There were no significant differences observed relating to the sex, age, duration of hospital stay, cost, success rate. However, the complication rate was significantly decreased in the PTBD group (8 cases (20.5%) vs. 22 cases (51.2%) P=0.0057). CONCLUSION: Form the comparison of the operation and PTBD groups, similar success rates were observed. Percutaneous transhepatic stone removal is also an effective method for the management of recurrent bile duct stones. After studying more cases, re-evaluation must be performed concerning the potential advantages of percutaneous transhepatic stone removal.

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.

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.

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.

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.

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.

Shoulder Impingement Syndrome: Evaluation of the Causes with MRI

PURPOSE: Various mechanical causes which induce shoulder impingement syndrome have been identified with the help of MRI. The aim of this study is to evaluate the incidence of such causes. MATERIALS AND METHODS: A total of 54 patients with clinically confirmed shoulder impingement syndrome and a normal control group(n=20) without symptoms were included. We evaluated the incidence of hook shaped acromion, low lying acromion, downward slope of the acromion, subacromial spur, acromioclavicular joint hypertrophy, coracoacromial ligament hypertrophy, high cuff muscle bulk, and os acromiale. RESULTS: Among the 54 patients, the following conditions were present: acromioclavicular joint hypertrophy(n=36), coracoacromial ligament hypertrophy(n=20), subacromial spur(n=18), downward sloping of the acromion(n=16), hook shaped acromion(n=11), relatively high cuff muscle bulk(n=6), low lying acromion relative to the clavicle(n=3), and os acromiale(n=1). In the normal control group there were nine cases of acromioclavicular joint hypertrophy, nine of coracoacromial ligament hypertrophy, nine of downward sloping acromion, and three of low lying acromion, but hook shaped acromion, high cuff muscle bulk, and os acromiale were not found. Among 54 patients, the syndrome was due to five simultancous causes in one patient, four causes in two, three causes in 12, two causes in 22, and one cause in 17. CONCLUSION: Hook shaped acromion and subacromial spur are the statistically significant causes of shoulder impingement syndrome. In 69 % of patients, the condition was due to more than one cause.

CT Findings of Post Urinary Dive rsion: Normal Findings and Detection of Cancer Recurrence

PURPOSE: To determine normal postoperative CT findings and tumor recurrence in patients who have under-goneradical cystectomy and urinary diversion. MATERIALS AND METHODS: We retrospectively reviewed the postoperative CTscans of 51 patients who had un-dergone radical cystectomy with urinary diversion, and in analysis speciallyemphasised normal postoperative CT findings and recurrent cancer in the surgical bed. Among these 51 patients, 43had undergone incontinent urinary diversion(Bricker operation), while for six, diversion had been continent (Kockprocedure). Attempts were also made to characterise the CT findings of each procedure according to the location ofthe ileal pouch, the pattern of contrast collection within the pouch, and the morphology of the ileocutaneostomysite. RESULTS: Each urinary diversion procedure demonstrated characteristic postoperative CT appearances. TheBricker procedure revealed a contrast-filled ileal conduit in the right lower quadrant excreting into theileocu-taneostomy site, while the Kock procedure demonstrated layering of contrast and urine within the pouch aswell as artificially intussuscepted afferent and efferent ileal loops at the anastomotic sites. Thirty-three smallsoft tissue density lesions in the surgical bed were seen in 19 patients (37%). Thirty one were bilateral (n=28)or unilateral (n=3) triangular or oval shaped soft-tissue-density lesions and two were unilateral irregular shapedlesions. Follow-up CT scans showed that all triangular or oval-shaped lesions were smaller (n=8) or show no changein size (n=23) ; they were thought to represent postoperative fibrosis or granulation tissue. Two cases ofirregular-shaped soft-tissue-density lesions were seen on follow-up CT scans to be larger, and these wereconfirmed by percutaneous biopsy to be recurrent cancer. CONCLUSION: It is important for the radiologist to befamiliar with normal postoperative CT findings of various urinary diversion procedures as well as to recognize arelatively high incidence (37%) of small soft tissue den-sity lesions in a surgical bed. In our study, smalltriangular or oval-shaped soft-tissue-density lesions in the sur-gical bed (especially when these were bilateral)were thought to represent postoperative fibrosis or granulation tissue, and close follow-up by means of CTscanning rather than an invasive procedure is therefore warranted.

Interstitial Laser Photocoagulation with Diode Laser Unit in Bovine Liver

PURPOSE: To evaluate the extent of tissue coagulation during interstitial laser photocoagulation (ILP) innormal bovine liver, using a diode laser unit and various parameters, and to determine whether the procedure isapplicable to clinical practice.. MATERIALS AND METHODS: Using an 18-gauge needle, experimental interstitiallaser photocoagulation (ILP) was carried out in normal bovine liver. On the basis of differing parameters, threegroups were established. For group I, a single photofiber with laser power of 1, 3 and 5 watts and an exposuretime of 60, 180, 300, 420 or 600 seconds was used. For groups II and III, four needles were fixed at a distance of1cm and 1.5cm ; in each case a needle fixation device was used, as well as a laser distributor for simultaneouslaser exposure of photofibers. As a control, four photofibers were placed as for groupIII, but to compare groups IIand III, each photofiber was exposed to a laser of 3 watts 300 seconds, without using a laser distributor. Toevaluate the range of tissue coagulation, specimens were analyzed both with regard to cross-sectional grossfindings and histopathologically . RESULTS: The largest diameter of thermal coagulation necrosis in Group I was15x15mm, and this was ball-shaped. Coalescence of coagulation between each photofiber was observed in Group II,and this was up to 25 mm in diameter. In Group III and controls, coalescence was not found, though the extent oftissue coagulation increased with increasing wattage and exposure time. The extent of charring at the center ofcoagulation also increased with increasing wattage. Smoke bubbles emanating from the coagulation area wereobserved, and during ILP involving a single photofiber, increased from 3 watts, applied for 300 seconds.CONCLUSION: Using an 8-gauge needle and a diode laser ILP, we have shown that a range of tissue coagulationacutely ablates normal bovine liver. In selective cases, the procedure could be applied to clinical trials.

Percutaneous biopsy of malignant hepatic tumor in patients with bleeding tendency: Usefulness of gelfoamplugging up the biopsy track

PURPOSE: To plug the biopsy site in eight patients with coagulopathy who had undergone percutaneous liverbiopsy. To this end, gelfoam cartridge was used as a sealant. MATERIALS AND METHODS: Using an 18G Tru-Cut-typedisposible automated biopsy gun(Soo Ho Medi-tech, Seoul, Korea) and under US guidance, eight patients underwentpercutaneous liver biopsy. After the gun had fired, the biopsy specimen in the inner stylet was retrieved whilethe outer cannula was held in place ; the cannula was then used to plug the biopsy tracks with gelfoam, using twoor three cartridges. If bleeding occurred, this was controlled by the use of more gelfoam cartridges. RESULTS: Diagnostic target tissue was obtained in seven of the eight patients(87.5%). Hepatocellular carcinoma wasdiagnosed in five cases and metastatic cancer in two. Profuse bleeding was observed in one patient(12.5%) andresolved by gelfoam plugging. CONCLUSION: We believe that in patients with coagulopathy who are required toundergo liver biopsy plugging the liver biopsy track with gelfoam cartridge is a simple, safe and useful method.