Effect of prophylactic benzydamine hydrochloride on postoperative sore throat and hoarseness after tracheal intubation using a double-lumen endobronchial tube: a randomized controlled trial.

PURPOSE: We evaluated the prophylactic effect of benzydamine hydrochloride (BH) spray on postoperative sore throat and hoarseness secondary to intubation with a double-lumen endobronchial tube (DLT). METHODS: Ninety-two adult patients undergoing thoracic surgery using DLT intubation were studied. The DLT cuff and oropharyngeal cavity were sprayed with normal saline (Group S; n = 46) or BH (Group BH; n = 46) prior to intubation. Postoperative sore throat and hoarseness were evaluated at one, six, and 24 hr after surgery. Sore throat was evaluated using a 0-100 mm visual analogue scale (VAS). Hoarseness was defined as a change in voice quality. RESULTS: Compared with Group S, postoperative sore throat occurred less frequently in Group BH at one hour (mean difference, 28.3%; 95% confidence interval [CI], 8.7 to 45.1; P = 0.01), at six hours (mean difference, 32.6%; 95% CI, 12.6 to 49.2; P < 0.01), and at 24 hr (mean difference, 28.3%; 95% CI, 9.3 to 44.7; P = 0.01) after surgery. Group BH had lower VAS scores for postoperative sore throat at one hour (mean difference, 12.8; 95% CI, 4.9 to 20.7), at six hours (mean difference, 11.9; 95% CI, 4.8 to 19.1; P < 0.01), and at 24 hr (mean difference, 5.3; 95% CI, 0.9 to 9.7; P = 0.01) after surgery. Hoarseness also occurred less frequently in Group BH at one hour (mean difference, 23.9%; 95% CI, 6.8 to 39.6; P = 0.01), at six hours (mean difference, 23.9%; 95% CI, 7.4 to 39.3; P = 0.01), and at 24 hr (mean difference, 21.7%; 95% CI, 5.5 to 37.0; P = 0.02) after surgery (P < 0.01). CONCLUSIONS: Prophylactic application of BH to the DLT cuff and oropharyngeal cavity reduces the incidence and severity of postoperative sore throat and the incidence of hoarseness associated with DLT intubation. The trial was registered at the Clinical Research Information Service (KCT0001068).

Effect of Jaw Thrust on Transesophageal Echocardiography Probe Insertion and Concomitant Oropharyngeal Injury.

OBJECTIVE: The aim of this study was to evaluate the effect of jaw thrust on transesophageal echocardiography probe insertion and concomitant oropharyngeal injury. DESIGN: A prospective, randomized study SETTING: Medical center governed by a university hospital PARTICIPANTS: Forty-two adult patients undergoing cardiovascular surgery were included. INTERVENTIONS: After the induction of anesthesia, a transesophageal echocardiography probe was inserted using an anterior jaw lift technique (conventional group, n = 21) or a jaw thrust-assisted technique (jaw thrust group, n = 21). MEASUREMENTS AND MAIN RESULTS: The incidence of oropharyngeal injury, number of insertion attempts, blood on the probe tip, and presence of persistent oropharyngeal bleeding were evaluated. In the conventional group, oropharyngeal injury occurred more frequently than in the jaw-thrust group (52.4% v 9.5%, respectively; p = 0.006). Regarding transesophageal echocardiography probe insertion, the conventional group required more attempts than the jaw-thrust group (p = 0.043). The incidence of blood on the probe tip was higher in the conventional group than in the jaw-thrust group (p = 0.020), but the presence of persistent oropharyngeal bleeding was similar between the 2 groups. CONCLUSIONS: The jaw-thrust maneuver facilitated the insertion of the transesophageal echocardiography probe and reduced concomitant oropharyngeal injury.

Propofol-ketamine or propofol-remifentanil for deep sedation and analgesia in pediatric patients undergoing burn dressing changes: a randomized clinical trial.

OBJECTIVE: In this study, we compared the propofol-ketamine and propofol-remifentanil combinations for deep sedation and analgesia during pediatric burn wound dressing changes. METHODS: Fifty pediatric patients aged 12-36 months, undergoing burn wound dressing changes, were randomly assigned to receive propofol-remifentanil (group PR) or propofol-ketamine (group PK) for deep sedation and analgesia. Patients in the group PR received 2 mg·kg(-1) propofol and 0.1 µg·kg(-1) remifentanil, and 0.05 µg·kg(-1) ·min(-1) remifentanil was infused continuously until the end of the procedure. Patients in the group PK received 2 mg·kg(-1) propofol and 1 mg·kg(-1) ketamine, and the same volume of isotonic saline was infused continuously until the end of the procedure. Additional propofol with remifentanil or ketamine was administered when required. Hemodynamic variables, drug requirements, occurrence of patient movement, surgeon's satisfaction score, recovery time, and the incidence of adverse events were recorded throughout the procedure and recovery. RESULTS: Recovery time was significantly shorter in the group PR compared to that in the group PK (10.3 [9.1-11.5] min vs 22.5 [20.3-25.6] min, median [interquartile range], respectively; P < 0.001). No significant hypotension or bradycardia occurred throughout the procedure. No significant differences were observed in terms of drug requirements, occurrence of patient movement, surgeon's satisfaction, incidence of respiratory depression, hypoxia, or nausea and vomiting CONCLUSIONS: The combinations of propofol-ketamine and propofol-remifentanil were effective for sedation and analgesia in pediatric patients undergoing burn dressing changes, but the propofol-remifentanil combination provided faster recovery compared to the propofol-ketamine combination.

Insulin/glucose infusion successfully resuscitates bupivacaine-induced sudden-onset circulatory collapse in dogs.

PURPOSE: In previous studies, insulin reversed the cardiac toxicity gradually induced by a continuous infusion of bupivacaine. In this randomized controlled study, we intended to simulate a more relevant clinical situation by injecting bupivacaine rapidly as a bolus to induce sudden-onset circulatory collapse in dogs. We then evaluated the insulin effect. METHODS: Bupivacaine (10 mg.kg(-1) iv) was rapidly administered intravenously to 12 dogs. At the onset of circulatory collapse (defined as a mean arterial pressure [MAP] of 30 mmHg), external chest compression was initiated. Insulin (2 U.kg(-1) iv) was given to the insulin-glucose (IG) group (n = 6) and the same volume of 0.9% saline was given to the control (C) group (n = 6). The primary outcome was successful resuscitation defined as both MAP ≥ 60 mmHg and sinus rhythm on an electrocardiogram that lasted ≥ 60 sec. Hemodynamic and blood variables were measured, including cardiac output and electrocardiogram intervals. RESULTS: All IG dogs were successfully resuscitated within 15 (3) min, whereas none of the control dogs were resuscitated (P = 0.002). After circulatory collapse, the average MAP was higher in group IG than in group C (P = 0.006). CONCLUSION: Insulin effectively reversed the sudden-onset circulatory collapse in dogs caused by an intravenous bolus injection of bupivacaine.

Effects of intravenous iron combined with low-dose recombinant human erythropoietin on transfusion requirements in iron-deficient patients undergoing bilateral total knee replacement arthroplasty.

BACKGROUND: The authors examined the impact of parenteral iron and recombinant human erythropoietin-ß (rHuEPO-ß) administered in the bilateral total knee replacement arthroplasty (TKRA), on postoperative anemia and transfusion requirements in iron-deficient patients. STUDY DESIGN AND METHODS: A total of 108 iron-deficient patients were randomly assigned to two groups: Group C (control) or Group IE (200 mg of iron sucrose intravenously over 1 hr and 3000 IU of rHuEPO-ß subcutaneously during the operation and during the postoperative period if the hemoglobin [Hb] level was 70-80 g/L). One or 2 units of blood were transfused to patients in both groups according to postoperative Hb level (between 60 and 70 g/L or betweeen 50 and 60 g/L, respectively). Perioperative laboratory and clinical outcomes (Hb, iron variables, postoperative bleeding amount, and number of units of RBCs transfused and incidences) were documented. RESULTS: Although preoperative Hb and the amount of postoperative bleeding were comparable in the two groups, Hb levels at 1, 2, and 3 days and at 2 and 6 weeks postoperation were significantly higher in Group IE. Furthermore, the transfusion rate was significantly lower in Group IE (20.4% vs. 53.7%, p=0.011) and the mean number of red blood cell units transfused was markedly lower in Group IE (0.2±0.5 vs. 0.8±0.8, p=0.005). Postoperative iron, ferritin, and transferrin saturation levels were significantly higher in Group IE. CONCLUSIONS: Treatment with parenteral iron and low-dose rHuEPO-ß in bilateral TKRA effectively attenuated anemia and decreased transfusion requirements in iron-deficient patients.

Detection of liver malignancy with gadoxetic acid-enhanced MRI: is addition of diffusion-weighted MRI beneficial?

AIM: To determine the additive value of diffusion-weighted MRI (DWI) to gadoxetic acid-enhanced MRI for the detection of hepatic metastases and hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Thirty-five patients with 38 liver metastases and 18 HCCs were included in this study. Ten patients also had hemangiomas (n = 3) or cysts (n = 8). Liver MRI consisted of pre-contrast and gadoxetic acid-enhanced 3D T1-weighted MRIs (arterial, portal, 2-min delay, 20 min hepatocyte-selective phases), a post-contrast T2-weighted image, and post-contrast DWI (b values: 0, 50, 600 s/mm²). Two observers independently analyzed the gadoxetic acid-enhanced MRI with and without DWI. The diagnostic accuracy and sensitivity for the detection of liver lesions were evaluated using receiver operating characteristic analysis. RESULTS: Although there were no significant differences in diagnostic accuracy for detecting metastases and HCCs between the gadoxetic acid set alone and the combined DWI and gadoxetic acid set for both observers (mean Az, 0.974 vs 0.987), we found the sensitivity for detecting metastases to be significantly higher with the combined images (97.4%) than with the gadoxetic acid set alone (89.5%) for observer 1 (p = 0.008). Three and two metastases for each observer were clearly verified by adding DWI to gadoxetic acid-enhanced MRI. However, sensitivities for both image sets were equivalent in detecting HCCs. CONCLUSION: The addition of DWI to gadoxetic acid-enhanced MRI has the potential to increase sensitivity for the detection of liver metastases. However, for detecting HCC, we found no additive value of DWI to gadoxetic acid-enhanced MRI.

Differentiating focal eosinophilic liver disease from hepatic metastases using unenhanced and gadoxetic acid-enhanced MRI.

PURPOSE: To examine the differential features of focal eosinophilic liver disease (FELD) from liver metastases on gadoxetic acid-enhanced MRI. MATERIALS: Twenty patients with 41 FELD and 20 patients with 55 metastases were enrolled in this study. Liver MRI consisted of precontrast 2D T1-weighted image (T1WI) and gadoxetic acid-enhanced 3D T1WI (arterial, portal, 20 min hepatocyte-selective phases), and a postcontrast T2WI. Images were analyzed for the margin and shape of the lesions; lesion conspicuity on T1- and T2WI; signal intensity of the lesions on 3D T1WI; presence of rim enhancement and misty signs; and presence of significant smaller lesions on the unenhanced T1WI (<50%) compared to hepatocyte phase image. RESULTS: Univariate analysis revealed the following significant parameters to favor FELD: a fuzzy margin, irregular shape, subtle signal intensity changes on T1- and T2WI, absence of target signs on the hepatocyte phase image, presence of misty signs, and size discrepancies on T1WI and hepatocyte phase images. Multivariate analysis revealed only a significantly smaller lesion size on T1WI compared to hepatocyte phase images to be predictive of FELD. CONCLUSION: A significantly smaller lesion size on T1WI relative to hepatocyte phase image is the best predictor for identifying FELD on gadoxetic acid-enhanced MRI.

Role of fat-suppressed t1-weighted magnetic resonance imaging in predicting severity and prognosis of acute pancreatitis: an intraindividual comparison with multidetector computed tomography.

OBJECTIVE: To determine the diagnostic value of magnetic resonance (MR) grading focusing on elevated signal on T1-weighted images in the prediction of severity and prognosis of acute pancreatitis as compared with the Balthazar computed tomography (CT) grading. MATERIALS: Thirty-one patients with acute pancreatitis who underwent CT and MR imaging including fat-suppressed T1-weighted images within a 48-hour interval were included in this study. The severity of pancreatitis was evaluated by 2 observers using the Balthazar CT grading system and an MR grading system that is focused on an elevated signal on T1-weighted images. The MR grading was correlated with the CT grading, and each MR or CT grade was compared with patient outcome parameters, including the duration of hospitalization, local and systemic complications, and clinical outcome grading. RESULTS: There was a significant correlation between CT and MR gradings for pancreatic or peripancreatic inflammation (r = 0.688, P < 0.01). However, for all of the outcome parameters and outcome grading, a stronger correlation was seen with the MR grading than with the CT grading. No significant correlation was found between CT grading and infected necrosis (r = 0.316, P = 0.083). CONCLUSIONS: Magnetic resonance imaging including fat-suppressed T1-weighted images is more accurate to predict the severity and prognosis of acute pancreatitis in comparison with CT.

Detection of hepatocellular carcinoma: gadoxetic acid-enhanced 3-dimensional magnetic resonance imaging versus multi-detector row computed tomography.

PURPOSE: The aim of this study was to compare the diagnostic accuracy and sensitivity of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with multi-detector row computed tomography (MDCT) for the detection of hepatocellular carcinomas (HCCs). MATERIALS: Sixty-two patients (81 HCCs) who underwent MDCT and gadoxetic acid-enhanced MRI using a 3-dimensional volumetric interpolated technique with a mean interval of 7 days (range, 3-11 days) were included in this study. Two observers reached a consensus on 2 sets of images: the gadoxetic acid set (unenhanced, early dynamic, 10-minute, and 20-minute hepatocyte phase images) and the 3-phase MDCT. Diagnostic accuracy and sensitivity were evaluated using the alternative-free response receiver operating characteristic method. RESULTS: There was a trend toward increased area under the receiver operating characteristic curve (Az value) for the gadoxetic acid set (0.963) as compared with the MDCT (0.930), but no significant difference was found (P = 0.41). Sensitivity of the gadoxetic acid set (91.4%) was better than that of the MDCT (71.6%; P = 0.0001). There were 12 lesions that showed only arterial hypervascularization on MDCT but showed arterial hypervascularization and delayed hypointensity on the gadoxetic acid set. CONCLUSIONS: Gadoxetic acid-enhanced MRI, including hepatocyte phase imaging, is more sensitive than MDCT for the detection of HCCs.

Added diagnostic value of T2-weighted MR imaging to gadolinium-enhanced three-dimensional dynamic MR imaging for the detection of small hepatocellular carcinomas.

PURPOSE: To assess the added value of T2-weighted MRI to gadolinium-enhanced dynamic MRI for detection of HCCs. MATERIALS AND METHODS: Two readers retrospectively analyzed MRIs of 115 patients with 131 HCCs (size; 0.6-2.0 cm) that had been diagnosed by histology (n=41) or imaging findings (n=90). Two separate blind image analyses of the gadolinium set and the combined T2-weighted imaging and gadolinium sets were performed. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method with four-point scale. Sensitivity and positive predictive value were also calculated. RESULTS: For both observers, the Az values and sensitivities with the combined T2-weighed imaging and gadolinium set (mean Az 0.806, sensitivity 84.7) were significantly higher than those with the gadolinium set (mean Az 0.660, sensitivity 59.9) (p<0.05). The addition of T2-weighted imaging led to a change in diagnosis for 27 lesions by both observers, which at gadolinium set were assigned a confidence level of 1 or 2 but at additional reading of T2-weighted imaging were assigned a confidence level of 3 or 4. For the positive predictive values, each image set showed a similar value for each observer. CONCLUSION: The addition of T2-weighted imaging to gadolinium-enhanced 3D dynamic imaging could be helpful in the detection of HCC by increasing reader confidence for HCCs with equivocal findings on gadolinium-enhanced MRIs.

Small malignant hepatic tumor detection in gadolinium- and ferucarbotran-enhanced magnetic resonance imaging: does combining ferucarbotran-enhanced T2*-weighted gradient echo and T2-weighted turbo spin echo images have additive efficacy?

OBJECTIVE: To determine if a combination of ferucarbotran-enhanced T2*weighted-gradient echo (T2*W-GRE) and T2-weighted turbo spin echo (T2W-TSE) images in gadolinium- and ferucarbotran-enhanced MRI has additive efficacy compared to each image alone for detecting small (< or = 2.0 cm) hepatocellular carcinoma (HCC) lesions in a group of cirrhotic patients and metastases in a group of non-cirrhotic patients. MATERIALS AND METHODS: Two readers retrospectively analyzed gadolinium- and ferucarbotran-enhanced T2*W-GRE, T2W-TSE, and combined T2*W-GRE/T2W-TSE images of 119 patients with 157 HCCs and 32 patients with 98 metastases. The diagnostic accuracy and sensitivity for each image set and the combined set were evaluated using the alternative-free response receiver operating characteristic method. RESULTS: The mean area under the curve value of the combined set (0.966) tended to be better than that for each individual image set (T2W-TSE [0.910], T2*W-GRE [0.892]). Sensitivities in the combined set were higher than those in each individual image set for detecting HCC (mean, 93.0% versus 81.6% and 86.7%, respectively, p < 0.01). Sensitivities in the combined set and the T2W-TSE set were the same for detecting metastases, and both were higher than the sensitivity seen in the T2*W-GRE set (mean, 97.5% versus 85.2 %, p < 0.01). CONCLUSION: Combining ferucarbotran-enhanced T2*W-GRE and T2W-TSE has additive efficacy for detecting HCC in cirrhotic patients, but T2W-TSE is preferred for detecting metastases in non-cirrhotic patients.

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.

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.

Perioperative complications following preoperative cessation of antithrombotic agents for total knee arthroplasty: A retrospective study.

The number of elderly patients undergoing total knee arthroplasty (TKA) has steadily increased. Elderly patients undergoing TKA usually have underlying diseases, and some of them take antithrombotic agents for the prevention or treatment of these co-morbidities, including cardiovascular, cerebrovascular, or thromboembolic diseases. When these patients are scheduled to undergo TKA, preoperative cessation of antithrombotic agents is considered on the basis of its risks and benefits. This study was aimed to evaluate the impact of discontinuing antithrombotic agents for primary total knee arthroplasty (TKA) on perioperative complications.Patients who underwent primary TKA between 2008 and 2012 were identified, and classified into two groups: group A, in whom antithrombotic agents were ceased preoperatively, and group B, in which patients did not receive antithrombotic therapy. Patient characteristics, history of antithrombotic therapy, intraoperative blood loss, perioperative blood transfusion, postoperative 30-day complications, and postoperative hospital stay were recorded.Of 885 patients undergoing primary TKA, 218 (24.6%) patients were included in group A, and 667 (75.4%) in group B. Group A received transfusion more frequently than group B (P < 0.001). However, there was no difference between the two groups in terms of intraoperative blood loss, postoperative 30-day complications, and postoperative hospital stay.Patients who discontinued antithrombotic drugs before primary TKA do not have a higher incidence of postoperative 30-day complications, including cardiovascular, cerebrovascular, or thromboembolic events. Moreover, the estimated intraoperative blood loss was not different compared with patients not receiving antithrombotic agents preoperatively. Larger prospective studies of this issue are required.

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.

Percutaneous radiofrequency thermal ablation of lung VX2 tumors in a rabbit model using a cooled tip-electrode: feasibility, safety, and effectiveness.

RATIONALE AND OBJECTIVE: To evaluate the feasibility, safety, and effectiveness of percutaneous CT-guided transthoracic radiofrequency ablation (RFA) of lung VX2 tumors implanted in rabbits. MATERIALS AND METHODS: Thirty-five rabbits with implanted lung VX2 tumors were divided into two groups, an RFA group (n = 28) and a control group (n = 7). In the RFA group, RFA was performed on VX2 tumors using a 17-gauge internally cooled-tip electrode. Contrast-enhanced CT was performed before the RFA and on the same day, day 3, weeks 1, 2, 3, and months 1, 2, 6, and 9, after the RFA. The therapeutic efficacy was evaluated by CT and pathologic findings. RESULTS: RFA of lung tumors was technically successful in each instance. Complete tumor ablation was achieved in 19 of the 28 rabbits (67.9%) in the RFA group. Nine rabbits (32.1%) showed local tumor relapse and mediastinal lymph nodal or pleural metastasis. The animals in the control group died of end-stage malignancies with diffuse tumor spread and malignant pleural effusion (mean 26 +/- 2.7 days). There were 17 (60.7%) complications related to the procedure, ie, pneumothorax (n = 12), obstructive pneumonia (n = 3), hemothorax (n = 1), and burn (n = 1). RFA of centrally located VX2 tumors (in inner 2/3 of the lung) was more frequently associated with complications than RFA of peripherally located VX2 tumors ( P= 0.02). CONCLUSION: This experimental study demonstrates the feasibility of RFA therapy for treating lung VX2 tumors in rabbits, although RFA for central tumors carries the potential for major complications, including large pneumothorax or obstructive pneumonia.

Characterization of focal liver lesions with superparamagnetic iron oxide-enhanced MR imaging: value of distributional phase T1-weighted imaging.

OBJECTIVE: To determine the potential value of distributional-phase T1-weighted ferumoxides-enhanced magnetic resonance (MR) imaging for tissue characterization of focal liver lesions. MATERIALS AND METHODS: Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients referred for evaluation of known or suspected hepatic malignancies. Seventy-three focal liver lesions (30 hepatocellular carcinomas (HCC), 12 metastases, 15 cysts, 13 hemangiomas, and three cholangiocarcinomas) were evaluated. MR imaging included T1-weighted double-echo gradient-echo (TR/TE: 150/4.2 and 2.1 msec), T2*-weighted gradient-echo (TR/TE: 180/12 msec), and T2-weighted turbo spin-echo MR imaging at 1.5 T before and after intravenous administration of ferumoxides (15 mmol/kg body weight). Postcontrast T1-weighted imaging was performed within eight minutes of infusion of the contrast medium (distributional phase). Both qualitative and quantitative analysis was performed. RESULTS: During the distributional phase after infusion of ferumoxides, unique enhancement patterns of focal liver lesions were observed for hemangiomas, metastases, and hepatocellular carcinomas. On T1-weighted GRE images obtained during the distributional phase, hemangiomas showed a typical positive enhancement pattern of increased signal; metastases showed ring enhancement; and hepatocellar carcinomas showed slight enhancement. Quantitatively, the signal-to-noise ratio of hemangiomas was much higher than that of other tumors (p <.05) and was similar to that of intrahepatic vessels. This finding permitted more effective differentiation between hemangiomas and other malignant tumors. CONCLUSION: T1-weighted double-echo FLASH images obtained soon after the infusion of ferumoxides, show characteristic enhancement patterns and improved the differentiation of focal liver lesions.

Detection of small hypervascular hepatocellular carcinomas in cirrhotic patients: comparison of superparamagnetic iron oxide-enhanced MR imaging with dual-phase spiral CT.

OBJECTIVE: To compare the performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) maging at 1.5T and dual-phase spiral computed tomography (CT) for the depiction of small hypervascular hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Forty-three patients with 70 small nodular HCCs (5-20 mm; mean, 13.7 mm) were examined. Diagnosis was based on the results of surgical biopsy in 22 patients and by the combined assessment of MR imaging, lipiodol CT, alpha feto-protein levels, and angiographic findings in 21. MR imaging consisted of respiratory-triggered turbo spin-echo T2-weighted imaging, T1-weighted fast low-angle shot, and T2* -weighted fast imaging with steady-state precession imaging before and after SPIO enhancement. CT imaging was performed with 5-mm collimation and 1:1.4 pitch, and began 30 and 65 secs after the injection of 150 mL of contrast medium at a rate of 3 mL/sec. Two blinded observers reviewed all images independently on a segment-by-segment basis. Diagnostic accuracy was evaluated using receiver operating characteristics(ROC) analysis. RESULTS: The mean areas (Az) under the ROC curves were 0.85 for SPIOenhanced MR imaging and 0.79 for dual-phase spiral CT (p <.05). The mean sensitivity of SPIO-enhanced MR imaging was significantly higher than that of CT (p <.05), i.e. 70.6% for MR imaging and 58.1% for CT. MR imaging had higher false-positive rates than dual-phase spiral CT, but the difference was not statistically significant (3.7% vs 3.3%) (p >.05). CONCLUSION: SPIO-enhanced MR imaging is more sensitive than dual-phase spiral CT for the depiction of small hypervascular hepatocellular carcinomas.

Percutaneous radiofrequency thermal ablation with hypertonic saline injection: in vivo study in a rabbit liver model.

OBJECTIVE: To determine whether hypertonic saline (HS, 36% NaCl) injection prior to or during radiofrequency ablation (RFA) can increase the extent of thermally mediated coagulation in in-vivo rabbit liver tissue, and also to establish the ideal injection time in relation to RFA in order to maximize its effect on the extent of radiofrequency (RF)-induced coagulation. MATERIALS AND METHODS: In 26 rabbits, 43 RFA lesions were produced using a 17-gauge internally cooled electrode with a 1-cm active tip under ultrasound (US) guidance. Rabbits were assigned to one of three groups: Group A: RFA alone (n=8); Group B: RFA after the instillation of 1 mL HS (n=8); Group C: RFA after and during the instillation of 0.5 mL HS (n=10). RF energy (30 W) was applied for 3 minutes, and changes occurring in tissue impedance, current, power output, and the temperature of the electrode tip were automatically measured. After RFA, contrast-enhanced spiral CT was performed, and in each group the maximum diameters of the thermal lesions in gross specimens were compared. Technical success and the complications arising were evaluated by CT and on the basis of autopsy findings. RESULTS: All procedures were technically successful. There were six procedure-related complications (6/26; 23%), including five localized perihepatic hematomas and one thermal injury to the stomach. With instillation of HS in group B rabbits, markedly decreased tissue impedance (73 Omega+/-5) and increased current (704 mA+/-41) were noted, compared to RF ablation without saline infusion (116.3 Omega+/-13, 308 mA+/-80). With instillation of the solution before RFA (group B), coagulation necrosis was greater (14.9 mm+/- 3.8) than in rabbits not injected (group A: 11.5 mm+/-2.4; Group A vs. B: p <.05) and in those injected before and during RFA (group C: 12.5 mm+/-3.1; Group B vs. C: p >.05). CONCLUSION: RFA using HS instillation can increase the volume of RFAinduced necrosis of the liver with a single application, thereby simplifying and accelerating the treatment of larger lesions. In addition, HS instillation before RFA more effectively achieves coagulation necrosis than HS instillation before and during RFA.