Biomedical subjects

Young Kon Kim

Publications and source records attributed to Young Kon Kim.

At least 19 recordsLinked to original sources

PubMed2006

Efficacy and safety of radiofrequency ablation of hepatocellular carcinoma in the hepatic dome with the CT-guided extrathoracic transhepatic approach.

PURPOSE: The purpose of this study was to determine the efficacy and safety of radiofrequency (RF) ablation for the treatment of hepatocellular carcinoma (HCC) in the hepatic dome with CT-guided extrathoracic transhepatic approach. MATERIALS AND METHODS: Fifteen patients with 15 HCCs (size range: 0.8-4 cm, mean size: 1.8 cm) in the hepatic dome were treated by RF ablation using cooled-tip electrodes and with CT-guided extrathoracic transhepatic approach. Therapeutic response of the tumor to RF ablation and procedure-related complications including hepatic injury, hemoperitoneum, and thermal injury of diaphragm were evaluated. RESULTS: The average number of needle punctures to ensure the correct needle position in the targeted tumor was 3.7 (range: 1-6 punctures). The average ablation time was 14.7 min (range: 8-25 min). Complete necrosis without marginal recurrence after at least 13-month follow-up was attained in 13 tumors (86.7%). There were no major complications related to the procedures. Six patients had shoulder pain that lasted three days to two weeks after the procedures and their symptoms were resolved with conservative treatment. CONCLUSIONS: RF ablation using CT-guided extrathoracic transhepatic approach is an effective and safe technique for the treatment of HCC in the hepatic dome.

Adult↗

PubMed2006

Detection and characterization of liver metastases: 16-slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging.

The aim of our study was to compare the diagnostic performance of 16--slice multidetector computed tomography with that of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging in the detection of small hepatic metastases and in the differentiation of hepatic metastases from cysts. Twenty-three patients with 55 liver metastases and 14 liver cysts underwent SPIO-enhanced MR imaging and multiphasic CT using 16-MDCT. Two observers independently analyzed each image, in random order. Sensitivity and diagnostic accuracy for lesion detection and differentiation as metastases or cysts for MDCT and SPIO-enhanced MR imaging were calculated using receiver operating characteristic analysis. For all observers, the Az values of SPIO-enhanced MR imaging for lesion detection and differentiation of liver metastases from cysts (mean 0.955, 0.999) were higher than those of MDCT (mean 0.925, 0.982), but not statistically significantly so (P > 0.05). Sensitivity of SPIO-enhanced MR imaging with regard to the detection of liver metastases (mean 94.5%) was significantly higher than that of MDCT (mean 80.0%) (P < 0.05). SPIO-enhanced MR imaging and 16-MDCT showed similar diagnostic accuracies for detection and differentiation of liver metastases from cysts, but sensitivity of SPIO-enhanced imaging in the detection of liver metastases was superior to that of 16-MDCT.

Adult↗

PubMed2006

Effectiveness of MR imaging for diagnosing the mild forms of acute pancreatitis: comparison with MDCT.

PURPOSE: To assess the usefulness of MRI and determine which MR sequence is most effective for diagnosing the mild forms of acute pancreatitis. MATERIALS AND METHODS: Forty subjects (20 normal volunteers and 20 patients with a mild form of acute pancreatitis) underwent MRI with fat-suppressed T1-weighted fast low-angle shot (FLASH), half-Fourier acquisition single-shot turbo spin-echo (HASTE), and TSE short TI inversion recovery (TSE-STIR) sequences. The 20 patients with a mild form of acute pancreatitis underwent multidetector CT (MDCT) and MRI within a 24-hour interval. We qualitatively analyzed all of the images by assessing inflammatory changes in the pancreas and peripancreatic fat. We quantitatively compared differences in pancreas-liver contrast between the control and patient groups for each MR sequence by measuring the signal intensities of the pancreas and liver. RESULTS: TSE-STIR was the best of the four modalities for delineating peripancreatic and pancreatic inflammation (P < 0.01). TSE-STIR depicted definitive peripancreatic and pancreatic inflammation in 18 and 15 patients, respectively. MDCT depicted only three cases of peripancreatic inflammation. TSE-STIR was also produced the best the best quantitative results of the MR sequences (P = 0.09). CONCLUSION: MRI is helpful for diagnosing the mild forms of acute pancreatitis. We recommend the use of TSE-STIR imaging as part of the routine protocol for evaluating pancreatitis.

Adult↗

PubMed2006

Comparison of gadobenate dimeglumine-enhanced dynamic MRI and 16-MDCT for the detection of hepatocellular carcinoma.

OBJECTIVE: The objective of our study was to compare the diagnostic performance of gadobenate dimeglumine-enhanced MRI with that of 16-MDCT for the detection of hepatocellular carcinoma using receiver operating characteristic (ROC) curve analysis. MATERIALS AND METHODS: Thirty-one patients with 53 hepatocellular carcinomas underwent gadobenate dimeglumine-enhanced dynamic MRI and multiphasic CT using 16-MDCT within a mean interval of 5 days (range, 3-9 days). The dynamic MRI examination was performed using 3D fat-saturated volumetric interpolated imaging and sensitivity encoding on a 1.5-T unit. Both dynamic MRI and multiphasic MDCT included dual arterial phase images. Three observers independently interpreted the CT and MR images in random order, separately, and without patient identifiers. The diagnostic accuracy of each technique was evaluated using the alternative-free response ROC method. The sensitivity and positive predictive values were also calculated. RESULTS: The sensitivities of gadobenate dimeglumine-enhanced MRI for all observers were significantly higher than those of MDCT for all the lesions and for lesions 1.0 cm or smaller (p < 0.05); however, for lesions larger than 1.0 cm, the sensitivities of the two imaging techniques were similar. The mean area under the ROC curve (A(z)) of gadobenate dimeglumine-enhanced MRI (0.87 +/- 0.03 [SD]) was higher than that of MDCT (0.83 +/- 0.04), but no significant difference was found between them (p = 0.31). The number of false-positive findings on dynamic MRI was slightly higher than on MDCT, but no significant difference in the positive predictive value between the two imaging techniques was detected (observer 1, p = 0.06; observer 2, p = 0.13; observer 3, p = 1.00). CONCLUSION: Gadobenate dimeglumine-enhanced MRI has a higher sensitivity for small hepatocellular carcinomas (</= 1 cm) but a higher false-positive rate due to nonspecific enhancement of benign lesions, such as arterioportal shunt, leading to no significant difference of overall accuracy when compared with MDCT.

Adult↗

PubMed2006

Radiofrequency ablation of hepatocellular carcinoma in patients with decompensated cirrhosis: evaluation of therapeutic efficacy and safety.

OBJECTIVE: Our objective was to determine the therapeutic efficacy and safety of radiofrequency ablation in the treatment of hepatocellular carcinoma (HCC) in patients with decompensated cirrhosis. SUBJECTS AND METHODS: Nineteen patients with 26 HCC nodules (range, 0.8-5 cm; mean, 1.96 cm) and decompensated liver cirrhosis (mean Child score, 10.7) were treated with radiofrequency ablation using cooled-tip electrodes and a 200-W generator. Radiofrequency ablation was performed under the guidance of sonography or CT. Procedure-related complications, therapeutic efficacy, each patient's survival, changes in blood test results--that is, serum aminotransferase and bilirubin--and changes in the Child score before and after ablation therapy were analyzed. To assess the therapeutic response of the tumor to radiofrequency ablation, we performed contrast-enhanced CT after the procedure and during follow-up. RESULTS: Complete necrosis without marginal recurrence at the 6-month follow-up was attained in 23 lesions (88.5%). During follow-up (mean, 13.3 months), one patient experienced a remote tumor recurrence in the liver. The median survival time was 12.0 +/- 1.7 months. Two patients died of liver failure--one at 2 months and one at 4 months after treatment. The other patients were followed for at least 6 months (range, 6-28 months; mean, 12 months). The first and second weeks after therapy, the serum aminotransferase and bilirubin levels were significantly higher than were pretreatment levels (p < 0.05). However, 3 weeks after therapy, those figures were nearly restored to the pretreatment levels. The mean Child scores 3 weeks after radiofrequency ablation (10.8) were similar to those before treatment (10.7). CONCLUSION: Radiofrequency ablation can be used selectively for treatment of HCC in patients with decompensated cirrhosis but has the potential to aggravate the preexisting hepatic dysfunction.

Adult↗

PubMed2006

Value of adding T1-weighted image to MR cholangiopancreatography for detecting intrahepatic biliary stones.

OBJECTIVE: The purpose of this study was to assess the value of adding a T1-weighted image to MR cholangiopancreatography (MRCP) to detect bile duct stones. MATERIALS AND METHODS: During a 30-month period, 148 patients suspected of having biliary stones and who underwent MRI including MRCP, a fat-suppressed T1-weighted fast low-angle shot (FLASH) sequence, and an axial HASTE sequence were enrolled in this study. The biliary stones were confirmed by ERCP, surgery, and percutaneous transhepatic cholangiography. Of these 148 patients, 73 had extrahepatic stones, 45 had intrahepatic stones, 20 had both extrahepatic and intrahepatic stones, and 10 had no biliary stones. Two separate sets of images, the MRCP set (composed of MRCP and axial HASTE) and the combined interpretion of the MRCP set and the T1-weighted image, were analyzed independently and separately by two observers. The diagnostic accuracy was evaluated using the receiver operating characteristic method. The sensitivity and specificity were also calculated. RESULTS: For common duct stones, the diagnostic accuracy and the sensitivity of both image sets showed similar values without any significant difference (0.998 [97.8%] for the combined interpretation; 0.988 [97.8%] for observer 1 and 0.995 [96.8%] for observer 2 for the MRCP set). However, for the intrahepatic stones, the diagnostic accuracy (0.993) and the sensitivity (98.5%) of the combined interpretation were significantly higher than those of the MRCP set for the two observers (0.926 [83.8%] for observer 1 and 0.922 [85.3%] for observer 2) (p < 0.05). No significant difference was seen in the specificity of the two image sets for both the intrahepatic and the common duct stones. CONCLUSION: Combining the axial T1-weighted image with MRCP is valuable for detecting intrahepatic stones.

Adult↗

PubMed2005

Hepatocellular carcinoma in patients with chronic liver disease: comparison of SPIO-enhanced MR imaging and 16-detector row CT.

PURPOSE: To compare the sensitivity, positive predictive value, and diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging with those of 16-detector row computed tomography (CT) for the detection of hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis. MATERIALS AND METHODS: Institutional Review Board approval was obtained for this study, and informed consent was obtained from all patients. A total of 44 patients (36 men, eight women; age range, 35-67 years) with 59 HCCs and mild liver cirrhosis (Child-Pugh score A or B) underwent multiphasic CT and SPIO-enhanced MR imaging. The diagnosis of HCC was established at surgical resection (n = 31) and percutaneous biopsy (n = 28). SPIO-enhanced MR imaging was composed of T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences. Multiphasic CT consisted of four phases (ie, early arterial, late arterial, portal venous, and equilibrium). Three observers independently analyzed each image in random order. Sensitivity, positive predictive value, and diagnostic accuracy were calculated by using the alternative free-response receiver operating characteristic analysis for multi-detector row CT and SPIO-enhanced MR imaging. RESULTS: Although not significant (P > .05), the area under the receiver operating characteristic curve for SPIO-enhanced MR imaging (mean, 0.90) was higher than that for multi-detector row CT (mean, 0.82) for all observers. Also, although no significant difference was demonstrated by any of the three observers (P > .05), there was a trend toward increased sensitivity on both a per-lesion and a per-patient basis for SPIO-enhanced MR imaging (mean, 84.7% and 94.7%, respectively) compared with multi-detector row CT (mean, 76.9% and 88.6%, respectively). No significant difference in positive predictive value was observed between modalities. CONCLUSION: SPIO-enhanced MR imaging and multiphasic CT show similar diagnostic accuracy, sensitivity, and positive predictive value for the detection of HCC in patients with relatively mild hepatitis B-induced cirrhosis.

Adult↗

PubMed2005

Feasibility of application of sensitivity encoding to the breath-hold T2-weighted turbo spin-echo sequence for evaluation of focal hepatic tumors.

OBJECTIVE: The purpose of this study is to assess the feasibility of the application of sensitivity encoding (SENSE) to the T2-weighted breath-hold turbo spin-echo (BHTSE) sequence for evaluating focal hepatic lesions. MATERIALS AND METHODS: Thirty consecutive patients with 43 focal liver lesions underwent BHTSE, BHTSE using SENSE with the conventional parameters, and BHTSE using SENSE with increased matrix and reduced echo-train length (ETL). There were 23 hepatocellular carcinomas in 21 patients, 10 hemangiomas in six, and 10 metastases in three. The images were compared quantitatively by measuring the signal-to-noise ratio (SNR) of the liver and the lesion and the lesion-liver contrast-to-noise ratio (CNR) and qualitatively by evaluating image quality, lesion conspicuity, artifact, and lesion detectability. RESULTS: The SNR of lesions and the lesion-liver CNR were highest on BHTSE using SENSE with increased matrix and reduced ETL, which were significantly higher than conventional BHTSE (p <0.05). In qualitative analysis, the image quality and conspicuity of malignant lesions with BHTSE using SENSE with increased matrix and reduced ETL were better than with BHTSE and BHTSE using SENSE with the conventional parameter (p <0.05). The image artifacts were lower with two BHTSEs using SENSE than with BHTSE (p <0.05). Lesion conspicuity of malignancy on BHTSE using SENSE with the conventional parameter was superior to those on BHTSE (p <0.05). Although there was no significant difference in the lesion detectability among the three images, two malignant lesions were clearly depicted on BHTSE using SENSE with increased matrix and reduced ETL. CONCLUSION: The application of SENSE to BHTSE can provide high-quality liver imaging with decreased acquisition time compared with conventional BHTSE.

Adult↗

PubMed2004

Detection of liver metastases: gadobenate dimeglumine-enhanced three-dimensional dynamic phases and one-hour delayed phase MR imaging versus superparamagnetic iron oxide-enhanced MR imaging.

The aim of this study was to compare the diagnostic performance of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging, including dynamic phases and one-hour delayed phase, versus superparamagnetic iron oxide (SPIO)-enhanced imaging for detection of liver metastases. Twenty-three patients with 59 liver metastases underwent Gd-BOPTA-enhanced MR imaging (unenhanced, arterial, portal, equilibrium and one-hour delayed phase) using three-dimensional volumetric interpolated imaging and SPIO-enhanced T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences on a 1.5-T unit. Three observers independently interpreted the three sets of images, i.e. Gd-BOPTA-enhanced dynamic MRI (set 1), delayed phase imaging (set 2) and SPIO-enhanced MRI (set 3). Diagnostic accuracy was evaluated using the alternative-free response receiver operating chracteristic (ROC) analysis. Sensitivity and positive predictive value were also evaluated. The mean accuracy (Az values) and sensitivity of Gd-BOPTA-enhanced delayed phase imaging (0.982, 95.5%) were comparable to those of SPIO-enhanced imaging (0.984, 97.2%). In addition, Az values and sensitivities of both imaging sets were significantly higher than those of Gd-BOPTA-enhanced dynamic images (0.826, 77.4%: p<0.05). There was no significant difference in the positive predictive value among the three image sets. Gd-BOPTA-enhanced delayed phase imaging showed comparable diagnostic performance to SPIO-enhanced imaging for the detection of liver metastases, and had a better diagnostic performance than Gd-BOPTA-enhanced dynamic images.

Adult↗

PubMed2004

Chemical, structural properties, and osteoconductive effectiveness of bone block derived from porcine cancellous bone.

The purpose of this study is to determine the efficacy of bioactive calcium phosphate obtained from porcine cancellous bone for the treatment of bone defects and nonunion. Porcine cancellous bone blocks were heat treated at 1300 degrees C for 2 h. The chemical composition, calcium-to-phosphate ratio, and microstructure of the porcine bone blocks were examined. For in vivo implantation, bone defects were created on the anteromedial aspect of the proximal tibia in seven beagle dogs and the xenograft bone blocks were placed into these defects. Plain radiographs were taken at 2-week intervals for roentgenographic evaluation. At 12 weeks, the specimens were stained with hematoxylin and eosin (H&E). The composition and morphology of heat-treated porcine cancellous bone were found to be similar to heat-treated human cancellous bone. Radiographs showed union between the host bone/bone-block interfaces. At 12 weeks, uniform and substantial new bone formation was observed. It is concluded that heat-treated porcine cancellous bone demonstrated effective osteoconductivity. This high-temperature heat-treatment technique has several advantages, including decreased risk of disease transmission and immunoreactivity, while also offering excellent biocompatibility.

Animals↗

PubMed2004

Three-dimensional dynamic liver MR imaging using sensitivity encoding for detection of hepatocellular carcinomas: comparison with superparamagnetic iron oxide-enhanced mr imaging.

PURPOSE: To assess the diagnostic performance of three-dimensional dynamic liver imaging with sensitivity encoding (SENSE), including double arterial phase images and increased resolution, by comparing it to superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for the detection of hypervascular hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-seven consecutive patients with 50 HCCs underwent Gd-BOPTA-enhanced dynamic imaging using SENSE and SPIO-enhanced MR imaging with at least a 24-hour interval between examinations. Using a three-dimensional gradient-echo technique applying SENSE, dynamic imaging consisting of double arterial phase-, portal phase- and delayed phase-images, was obtained. Using T2-weighted turbo spin-echo and T2*-weighted fast imaging with steady-state precession sequence, SPIO-enhanced MR imaging was obtained. For qualitative analysis, the diagnostic accuracy of both MR examinations for detecting the 50 HCCs was evaluated using the alternative free-response receiver operating characteristic method. Sensitivity and positive predictive value were also evaluated. RESULTS: The mean sensitivity and positive predictive value of three-dimensional dynamic imaging with SENSE were 91.3% and 89.2%, respectively, and those of SPIO-enhanced imaging were 77.3% and 92.6 %, respectively. There was a significant difference in sensitivity between the two images (P <0.05). The mean Az value of three-dimensional dynamic imaging with SENSE (0.97 +/- 0.01) was significantly higher than that of SPIO-enhanced imaging (0.90 +/- 0.02) (P=0.00). CONCLUSION: Three-dimensional dynamic liver MR imaging using SENSE for acquiring double arterial phase images is more efficient than SPIO-enhanced MR imaging for detecting HCCs.

Carcinoma, Hepatocellular↗

PubMed2004

Comparison of superparamagnetic iron oxide-enhanced and gadobenate dimeglumine-enhanced dynamic MRI for detection of small hepatocellular carcinomas.

OBJECTIVE: The purpose of this study was to compare superparamagnetic iron oxide (SPIO)-enhanced MRI with gadobenate dimeglumine-enhanced MRI for the detection of hepatocellular carcinoma using receiver operating characteristic (ROC) analysis. MATERIALS AND METHODS: Twenty-nine consecutive patients with 35 hepatocellular carcinomas underwent gadobenate dimeglumine-enhanced MRI (unenhanced, arterial, portal, and equilibrium phases) using 3D fat-saturated volumetric interpolated imaging and SPIO-enhanced MRI on a 1.5-T unit. SPIO-enhanced T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences were performed 48 hr after completion of the dynamic study. Three observers independently interpreted the images in random order, separately, and without patient identifiers. Diagnostic accuracy was evaluated using the alternative free response receiver operating characteristic method. Sensitivity and positive predictive value were also evaluated. RESULTS: The mean sensitivity and positive predictive value of SPIO-enhanced imaging were 81.0% and 85.0%, respectively, and those of gadobenate dimeglumine-enhanced MRI were 91.4% and 88.1%, respectively. A significant difference was seen in the sensitivity of the two MRI examinations (p < 0.05). The mean value of the area under the ROC curve (A(z)) for gadobenate dimeglumine-enhanced imaging (A(z) = 0.97 +/- 0.01) was significantly higher than that for SPIO-enhanced imaging (A(z) = 0.90 +/- 0.02) (p = 0.004). CONCLUSION: Gadobenate dimeglumine-enhanced 3D dynamic imaging showed better diagnostic performance than SPIO-enhanced imaging for the detection of hepatocellular carcinomas.

Adult↗

PubMed2003

Combined treatment of radiofrequency ablation and acetic acid injection: an in vivo feasibility study in rabbit liver.

The aim of this study was to compare the effects of percutaneous radiofrequency ablation (RFA) combined with percutaneous acetic acid injection (PAI) and either therapy alone for their effects on in vivo rabbit liver tissue. Thirty New Zealand white rabbits were included in this study and were allocated to three groups: group A, conventional RFA (n = 10); group B, PAI (n = 10); and group C, combined RFA and PAI (n = 10). Under US guidance, 1 ml of 50% acetic acid was injected into the target area of the liver parenchyma through a 21-G Chiba needle before performing RFA. The RFA was then performed using a 17-G internally cooled electrode with 1-cm active tip, and RF energy (30 W) was applied for 3 min with or without acetic acid injection. After RFA or PAI, contrast-enhanced CT and CT pathologic correlation were performed. The maximum diameters of the thermal lesions in each group were compared. All procedures were technically successful, and a total of 30 lesions (10 lesions for each group) were produced. The mean maximum diameter of the coagulation necrosis in the rabbits of group C (25+/-9 mm) was significantly larger than the diameters of the other groups: 12.2 +/- 1 mm (group A) and 14.3 +/- 3 mm (group B; p = 0.001). On contrast-enhanced CT scanning, the lesions of group B (7 of 10, 70%) appeared frequently irregular compared with those of groups A (2 of 10, 20%) and C (4 of 10, 40%; p = 0.08). There were seven complications (23.3%): a localized hematoma in a group-A rabbit; two hematomas and one chemical peritonitis in group-B rabbits; and a hematoma, a chemical peritonitis, and a burn injury to the stomach in group-C rabbits. Compared with the group-A rabbits (1 of 10, 10%), the group-B (3 of 10, 30%) and group-C rabbits (3 of 10, 30%) showed a tendency toward complications, but the difference was not significant (p = 0.48). Under the present experimental condition, combined RFA and PAI was able to increase the diameter of coagulation necrosis up to 2.5 cm without significantly increasing complications.

Acetic Acid↗

PubMed2003

Gadobenate dimeglumine-enhanced liver MR imaging: value of dynamic and delayed imaging for the characterization and detection of focal liver lesions.

The aim of this study was to determine the value of delayed-phase imaging (DPI) of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging for the evaluation of focal hepatic tumors compared with precontrast imaging and early dynamic phase imaging. The MR images were obtained in 48 patients with 98 focal hepatic tumors. Three-dimensional gradient-echo (GRE) imaging obtained before and 30, 60, and 1 h after administration of 0.1 mmol/kg of gadobenate dimeglumine. Each image set was analyzed qualitatively (lesion detection, conspicuity, delineation, and enhancement pattern on DPI) and quantitatively [signal-to-noise ratio (SNR), tumor-liver contrast-to-noise ratio (CNR)]. Improved lesion-to-liver contrast during the dynamic phase imaging was observed compared with precontrast images. The DPI showed a homogeneous enhancement of liver parenchyma and distinctive enhancement features of focal liver lesions: metastases (85%) showed a target shaped enhancement, and hepatocellular carcinomas (HCCs) showed an inhomogeneous (58%) or homogeneous enhancement (21%). The DPI showed better performance for the detection of metastases than other images by increasing lesion delineation ( p<0.05). The absolute CNR of metastasis measured from periphery of the tumors on DPI was greater than precontrast and arterial phase imaging ( p<0.05). The Gd-BOPTA during both dynamic and delayed phases provides valuable information for the characterization of focal liver lesions, and furthermore, Gd-BOPTA-enhanced DPI contributed to the improved detection of liver metastasis compared to precontrast and early dynamic imaging.

Adult↗

PubMed2003

Radio-frequency thermal ablation with hypertonic saline solution injection of the lung: ex vivo and in vivo feasibility studies.

The aim of this study was to assess the effects of simultaneous instillation of NaCl solutions during radio-frequency ablation (RFA) on the dimension of the ablated lesion in ex vivo bovine lung tissue and in vivo rabbit lung tissue. The RFA was induced in ex vivo bovine lung tissue which was inflated with room air and in vivo rabbit lung tissue by a 500-kHz RF generator and a 17-G cooled-tip electrode. In in vivo experiments, RFA was performed using CT guidance. The RF energy was applied for 5 min with or without instillation of 0.9 or 36% NaCl solutions. The changes in tissue impedance, current, power output, and temperature of the electrode tip were automatically measured. The maximum diameter of all thermal lesions was measured perpendicular to the electrode axis by two observers. In an ex vivo study, the mean lesion diameters using 36 and 0.9% NaCl solutions were larger than those of the control group: 51+/-8, 34+/-6, and 5+/-2 mm ( p<0. 05). In in vivo rabbit lung tissue, the mean lesion diameter with NaCl solution (15.3+/-3.1 mm) was larger than that of the lesion without NaCl solution (8.5+/-1.4 mm; p<0.05). With instillation of NaCl solutions, a marked decrease of tissue impedance (>100 Omega) and corresponding increase of current flow occurred in both ex vivo and in vivo studies. This experimental study demonstrates that RF ablation with simultaneous NaCl solution infusion of the lung is more effective in achieving coagulation necrosis than conventional RFA procedure.

Animals↗

PubMed2003

Combined radiofrequency ablation and hot saline injection in rabbit liver.

RATIONALE AND OBJECTIVES: To determine whether combining hot saline injection (HSI) and radiofrequency ablation (RFA) can increase the extent of thermally mediated coagulation in in vivo rabbit liver tissue. METHODS: In 66 rabbits, RF energy and/or hot saline-induced coagulations were produced using a 17-gauge cooled electrode or 21-gauge needle under ultrasound guidance. Rabbits were allocated into 1 of 5 groups: group A, RFA alone (n = 15); group B, HSI (1 mL hot saline infused, n = 10); group C, combined therapy for HSI followed by RFA (n = 21); group D, combined therapy for RFA immediately followed by HSI (n = 10); and group E, 1 mL room temperature saline infusion before RFA (n = 10). RF energy (30 W) was applied for 3 minutes. The changes in tissue impedance, current, power output, and temperature of the electrode tip were automatically measured. Before RFA, precontrast computed tomography was performed, and after RFA, pre- and postcontrast spiral computed tomographic scans were acquired. The maximum diameters of the thermal lesions on the gross specimens and complications of each group were compared. RESULTS: All procedures were technically successful. There were 9 of 61 procedure-related complications (14.8%) including 6 localized hematomas and 3 thermal injuries to the diaphragm and the stomach. In rabbits in groups C and E, a marked decrease of tissue impedance (43.4 omega, 44.1 omega) and an increase of current (709 mA, 722 mA) occurred with instillation of saline infusion compared with RFA only. Combined therapy for HSI followed by RFA produced a greater short-axis mean diameter of coagulation (14.6 +/- 4.3 mm) than that in rabbits of other groups, for RFA only (10.4 +/- 2.4 mm), HSI only (8.7 +/- 3.3 mm), and combined therapy for RFA immediately followed by HIS (12.0 +/- 1.4 mm; P < 0.05). CONCLUSION: Combined therapy for HSI followed by RFA can increase the volume of RFA-induced coagulation in the liver with a single application, and therefore may improve the results of RFA for the treatment of larger tumors.

Animals↗

PubMedDate not supplied

Combined therapy of radiofrequency ablation and ethanol injection of rabbit liver: an in vivo feasibility study.

Our purpose was to compare the effects of percutaneous radiofrequency ablation (RFA) combined with percutaneous ethanol injection (PEI) on the extent of ablation in in vivo rabbit liver tissue as compared with either therapy alone. Twenty-two New Zealand white rabbits were included in this study and allocated into three groups: group A: conventional RFA (n = 6); group B: PEI (n = 6): group C: combined RFA and PEI (n = 10). For combined RFA and PEI, under ultrasound guidance, 1 mL of absolute ethanol was injected into the target area of the liver parenchyma through a 21-gauge Chiba needle before performing RFA. RFA was performed using a 17-gauge internally cooled electrode with 1-cm active tip, and RF energy (30 W) was applied for 3 minutes, with or without ethanol injection. After RFA or PEI, contrast-enhanced computed tomography and CT-pathologic correlation were performed. The short-axis and long-axis diameters of thermal lesions of each group were compared. All procedures were technically successful and a total of 38 lesions were produced. The mean short-axis and long-axis diameter of the coagulation necrosis in rabbits of group C (combination of RFA and PEI), were significantly larger than those of other groups: group A: 10.3 +/- 2 mm and 11.4 +/- 2 mm: group B: 3.1 +/- 1 mm and 4.3 +/- 2 mm: group C: 12.8 +/- 3 mm and 17.8 +/- 6 mm (p < 0.05). On contrast-enhanced CT scan, the lesions of rabbits of the group C appeared to be more frequently irregular compared to those of group A (20% in group A vs. 67% in group C). There were three complications including two localized hematomas and one cardiopulmonary failure. Combined RFA and PEI could increase the dimension of coagulation necrosis without increasing complications and therefore, may be successfully used for treating larger lesions.

Analysis of Variance↗

PubMedDate not supplied

Solid organizing hepatic abscesses mimic hepatic tumor: Multiphasic computed tomography and magnetic resonance imaging findings with histopathologic correlation.

OBJECTIVE: To describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings of solid organizing hepatic abscesses and correlate them with the pathologic findings. METHODS: Ten patients with 10 pathologically proven solid organizing hepatic abscesses who underwent 3-phase CT (n = 10) or MRI (n = 7) were enrolled in this study. Images were retrospectively analyzed by consensus of 2 radiologists for attenuation (signal intensity), shape, and margin of the lesions as well as for their enhancement patterns. Their imaging findings were correlated with their pathologic findings. RESULTS: The main imaging finding on CT or MRI was the well-defined target appearance of a central enhancing area with a low-attenuation (signal intensity) rim on arterial and portal phases. On the delayed phase, most of lesions showed slightly low attenuation (signal intensity) with an enhancing rim, and 1 showed diffuse enhancement. Pathologically, the central areas and peripheral rims corresponded to granulation tissue and fibrosis, respectively. Nine lesions demonstrated a tiny necrotic cystic portion in the center. CONCLUSION: The target appearance of solid organizing hepatic abscesses on CT and MRI can be helpful in differentiating them from other focal liver lesions. These imaging findings are well correlated with the pathologic findings.

Adult↗