Maximum Diameter Of Lesions Research Articles

Evaluation of serial changes of pancreatic branch duct intraductal papillary mucinous neoplasms by follow-up with magnetic resonance imaging

The purpose of this study was to clarify the biological behaviour of branch duct type intraductal papillary mucinous neoplasm (IPMN) by evaluating serial changes at magnetic resonance cholangiopancreatography (MRCP). Fifty-two patients with a diagnosis of branch duct IPMN based on either endoscopic retrograde cholangiopancreatography (ERCP) (9/52) and/or MRCP examination (43/52), were followed up over a mean period of 31.2 months (range 12–108). All imaging data were retrospectively reviewed by two radiologists in order to evaluate serial changes in the maximum diameter of the cystic lesion, in the presence of main pancreatic duct dilatation (MPD), and filling defects within the lesion. Statistical analysis was performed using the Fisher exact probability test. Serial MRCP proved growth in seven cases. In two cases the size decreased; in the remaining 43 there was no change in size. Lesions greater than 3 cm at presentation and the presence of MPD dilatation or filling defects at imaging were most likely to grow. Only 2/37 cystic lesions less than 3 cm in diameter grew in size over the period of observation. No cystic lesion showed changes in morphology and structure. Branch duct IPMNs smaller than 3 cm, without associated filling defects, tend to be stable, making ‘watch and wait’ management possible.

Influence of Surgical Staples on Radiofrequency Ablation Using Multitined Expandable Electrodes

During radiofrequency ablation (RFA), there is a risk that the multitined expandable electrode will come into contact with one of the surgical staples used to treat local recurrence after surgical operations. Our objective was to evaluate whether a surgical staple would influence the RFA of egg white using a multitined expandable electrode. Multitined expandable electrodes, LeVeen needles (expandable diameter 3.0 cm), were sunk into an egg white bath with (a) no surgical staple, (b) a surgical staple touching one of the tines, or (c) a surgical staple touching two of the tines simultaneously. By connecting the LeVeen needle and copper plate at the bottom of the bath, RFA was then performed on the egg whites as a substitute for human tissue. Ten egg white baths were ablated under each of conditions (a), (b), and (c), for a total of 30 sets of coagulated egg white. There was no significant difference in the time from the power-on to the roll-off (i.e., the completion and shutting off of the electric circuit) or in the maximum diameter of the thermal lesion between conditions (a) and (b) or (a) and (c). However, the minimum diameter of the thermal lesion was significantly smaller in (c) compared with (a) (p < 0.01). Surgical staples have the capacity to interfere with the electromagnetic field and decrease the minimum diameter of the thermal lesion in the event that a staple touches two of the tines of a multitined expandable electrode during RFA. Although the difference might be small enough to be neglected under many clinical circumstances, we recommend that, if possible, the tines not be expanded near metallic material.

Contrast-enhanced ultrasonography in the follow-up of patients with hepatic metastases from breast carcinoma

Oncological treatment planning relies on the evaluation of treatment response, which is defined by the change in size of measurable lesions. The purpose of this study was to evaluate the use of contrast-enhanced ultrasound (CEUS) to obtain a precise measurement of hepatic metastases in breast cancer patients with fatty-liver disease. Twelve consecutive patients with 25 liver metastases from breast cancer and fatty liver disease, as defined by US criteria, were enrolled in this prospective study. All patients underwent conventional US, CEUS and multidetector computed tomography (MDCT), used as the gold standard for measuring the maximum diameter of lesions. Agreement between US, CEUS and MDCT measurements was analysed using Altman-Bland plots; 95% confidence limits were calculated for the difference among means. Mean diameter as measured by MDCT was 26.2 mm (range 11-83). US allowed measurement of 20/25 lesions. In 15 lesions, CEUS measurements were more accurate than those obtained by US. The difference among means was 1.1 mm with a 95% confidence interval (-9.2, 11.4) for US measurements and 0.6 mm with a 95% confidence interval (-2.0, 3.1) for CEUS. Our preliminary data show that CEUS can be used to obtain more accurate measurements than conventional US for the follow-up of patients with metastases in fatty liver.

Thyroid isthmusectomy: a critical appraisal

Thyroid lobectomy with isthmusectomy is the standard surgical technique for removal of unilateral thyroid nodules, and it involves the exposure of the tracheoesophageal grooves. Thyroid isthmusectomy is a surgical procedure that excises only the thyroid isthmus. It allows excision of a lesion without the exposure of the tracheoesophageal grooves. We aimed to demonstrate that isthmusectomy could be a safe alternative to thyroid lobectomy with isthmusectomy in patients with nodules confined to the isthmus or the pyramidal lobe. This was a prospective study performed over a five year period from 1999 to 2004. Inclusion criteria for thyroid isthmusectomy were: patients with a single lesion located in the region of the thyroid isthmus or the pyramidal lobe; maximum lesion diameter of 30 mm; and cytological reports of non-diagnostic appearance, follicular cells or suspicion of malignancy. Nine patients were identified with these criteria. Histology included two colloid nodules, three benign follicular adenomas, two Hurthle cell adenomas and two papillary thyroid carcinomas. There were no recorded complications. Thyroid isthmusectomy is a safe alternative to thyroid lobectomy with isthmusectomy in patients who have nodules confined to the isthmus and pyramidal lobe. Leaving a cuff of normal thyroid tissue has the advantage of not exposing the tracheoesophageal grooves, thus minimising potential damage to the recurrent laryngeal nerves and parathyroids. Surgeons performing isthmusectomies should be experienced in more complex thyroid surgical procedures.

Topographic Patterns of Small Subcortical Infarcts Associated with MCA Stenosis: A Diffusion‐Weighted MRI Study

Small subcortical infarcts (SSI, maximum lesion diameter < or =2.0 cm) are usually considered as infarcts caused by small vessel disease. However, SSI can also be associated with large artery occlusive disease such as middle cerebral artery (MCA) stenosis. We performed a prospective study to investigate the relationship between MCA stenosis and SSI distribution and further to investigate the mechanism of SSI caused by MCA stenosis. Magnetic resonance angiography (MRA) and diffusion-weighed MRI (DWI) of consecutive acute ischemic stroke patients with recent SSI were studied. The distribution of acute infarcts on DWI was categorized as cortical infarct (CI), border zone infarct (BI), or perforating artery infarct (PAI). Totally, 93 cases were recruited, among which 12 had single SSI with MCA stenosis (group 1) and 26 patients had multiple SSI with MCA stenosis (group 2), while 55 patients without MCA stenosis had single SSI (group 3). For patients with single SSI and MCA stenosis, 6 had BI and 6 had PAI; for patients with multiple SSI and MCA stenosis, 25 had BI, 4 had PAI and 9 had CI (compared with group 1: P= .001); for patients with single SSI but without MCA stenosis, 20 had BI and 35 had PAI (compared with group 1: P= .58). Multiple acute infarcts along the border zone are the commonest pattern in small infarcts with MCA stenosis, especially among those with multiple acute infarcts. Our data suggest that hemodynamic compromise and artery-to-artery embolism may be both important factors for infarcts in patients with MCA stenosis.

Magnetic Resonance Imaging for Assessment of Radiofrequency Lesions in Kidney Tissue Immediately after Ablation: An Experimental Study

Radiofrequency ablation (RFA) is an attractive minimally invasive treatment option for small renal masses. The purpose of this study was to investigate the morphologic imaging appearance of RF lesions immediately after the ablation of kidney tissue using standard clinical MR sequences, as well as to investigate the correlation between MR and gross lesion size. Ablations were performed 17 times in a standardized model of ex-vivo perfused porcine kidneys using a resistance-controlled RF device (250 W, 470 kHz) and a nonexpandable bipolar applicator inserted into the center of healthy renal parenchyma. The RF current was applied for 9 minutes at 20 W. Imaging was performed after ablation using standard clinical MR sequences: morphologic T(1)/T(2)- weighted images and an isotropic post-contrast T(1) high-resolution measurement (VIBE). Maximum lesion diameters were measured in three directions and were compared with the measurements of the gross lesions. Histologic (hematoxylin + eosin and nicotinamide adenine dinucleotide staining) and statistical analyses were performed. The gross pathologic examination showed a firm, white-yellow ablation zone sharply demarcated from the untreated tissue. The histologic examination confirmed cellular viability outside but not in the treatment zone. The RF lesions were hyperintense on T(1)-weighted images and hypointense on T(2)-weighted images. The lesion size measured in the VIBE images correlated best with the macroscopic lesion size (N = 16). Morphologic MR T(1) and T(2) sequences of RF lesions immediately after ablation produce reliable and consistent imaging characteristics. The post-contrast, high-resolution sequence (VIBE) enables the extent of the lesion to be determined accurately. The potential uses of this imaging strategy in clinical practise warrant further investigation on human renal-cell carcinoma.

Neuroradiologic and clinicopathologic features of dysembryoplastic neuroepithelial tumor

目的 探讨胚胎发育不良性神经上皮瘤(DNT)的MRI、CT表现及临床病理特征.方法回顾性分析经组织病理学证实的12例DNT的MRI、CT表现与临床病理特点.结果男6例,女6例,年龄12～68岁(平均36.7岁).大多数病例以癫痫小发作为主,神经系统检查无阳性体征.MR检查病变均位于幕上结构,累及皮层,额叶(4例)及颞叶(3例)为主;最大径2～5 cm不等,形态呈类圆形、分叶状或不规则状;2例累及白质, 7例伴囊性变.病变在MRI均呈T1WI低信号,T2WI高信号,无病变周围水肿及占位效应;囊性病变在T1WI信号均匀,等于或略高于脑脊液.6例CT扫描病变均呈低密度改变,其中2例呈囊性分叶状,1例呈局灶性钙化;4例增强后病变无强化,1例病变内呈轻度不均匀强化.病理组织学DNT分为3型:单纯型(4例)、复杂型(6例)及非特异型(2例).结论 DNT是一种良性病变,MRI较CT更具特征性表现。

Logistic Regression Model to Distinguish Between the Benign and Malignant Adnexal Mass Before Surgery: A Multicenter Study by the International Ovarian Tumor Analysis Group

To collect data for the development of a more universally useful logistic regression model to distinguish between a malignant and benign adnexal tumor before surgery. Patients had at least one persistent mass. More than 50 clinical and sonographic end points were defined and recorded for analysis. The outcome measure was the histologic classification of excised tissues as malignant or benign. Data from 1,066 patients recruited from nine European centers were included in the analysis; 800 patients (75%) had benign tumors and 266 (25%) had malignant tumors. The most useful independent prognostic variables for the logistic regression model were as follows: (1) personal history of ovarian cancer, (2) hormonal therapy, (3) age, (4) maximum diameter of lesion, (5) pain, (6) ascites, (7) blood flow within a solid papillary projection, (8) presence of an entirely solid tumor, (9) maximal diameter of solid component, (10) irregular internal cyst walls, (11) acoustic shadows, and (12) a color score of intratumoral blood flow. The model containing all 12 variables (M1) gave an area under the receiver operating characteristic curve of 0.95 for the development data set (n = 754 patients). The corresponding value for the test data set (n = 312 patients) was 0.94; and a probability cutoff value of .10 gave a sensitivity of 93% and a specificity of 76%. Because the model was constructed from multicenter data, it is more likely to be generally applicable. The effectiveness of the model will be tested prospectively at different centers.

Contracture of the Deltoid Muscle: Sonographic Evaluation with MRI Correlation

This article evaluates the sonographic features of deltoid contracture (DC) with MRI correlation. Two reviewers evaluated the imaging features in 22 painful shoulders of 20 patients with a sonographic diagnosis of DC and a subsequent confirming MRI study. The sonographic and MRI findings with regard to the lesion extent (assessed by a 3-point scale: 1 = less than or equal to one third of the longitudinal deltoid length involved, 2 = greater than one third and less than or equal to two thirds involved, and 3 = greater than two thirds involved), transverse lesion morphologic appearance, and maximal transverse diameter measured were compared with kappa statistics and Wilcoxon's signed rank test, respectively. Compared with MRI, there were two false-positive diagnoses of DC on sonography. Among the 20 true-positive diagnoses, sonography showed good agreement with MRI in assessing the lesion extent (kappa = 0.796, p < 0.001). Three sonographic lesion morphologic patterns for hyperechoic lesions (I = with multiple < 8-mm hypoechoic spots, II = heteroechoic lesions with predominant 8-15-mm hypointense areas, and III = > 15-mm calcified nodules, respectively) showed excellent agreement with three MRI lesion patterns (I = multiple < 8-mm hypointense spots, II = predominant 8-15-mm hypointense areas, and III = > 15-mm hypointense nodules, respectively) (kappa = 0.921, p < 0.001). However, the maximum lesion diameters appeared significantly larger on sonography than on MRI (2.8 +/- 0.6 cm vs 2.0 +/- 0.8 cm, mean +/- SD; p < 0.001), which was plausibly ascribed to the better sonographic delineation of hyperechoic immature fibrotic tissues. Sonography is helpful for evaluating DC and correlates well with MRI.

Hepatic Hemorrhage Caused by Percutaneous Tumor Ablation: Radiofrequency Ablation versus Cryoablation in a Porcine Model

To determine the extent of hepatic hemorrhage caused by percutaneous cryoablation performed with a small-diameter cryoablation probe compared with that caused by percutaneous radiofrequency (RF) ablation in a porcine model. The study was pre-approved by the institutional research animal care and use committee, and husbandry and experiments complied with National Institutes of Health standards for care and use of laboratory animals. Percutaneous hepatic ablation was performed in 18 domestic pigs (mean weight, 45 kg) by using a 17-gauge (1.5-mm-diameter) RF electrode (n = 6), a cluster of three RF electrodes (n = 6), or a 13-gauge (2.4 mm-diameter) cryoprobe (n = 6). Ablation was performed in four sites per liver. Total blood loss, minimum lesion diameter, maximum lesion diameter, and lesion volume were determined for each group and compared by using analysis of variance. Mean blood loss was 11.11 mL +/- 11.47 (standard deviation), 105.29 mL +/- 175.58, and 28.06 mL +/- 30.97 with the single RF electrode, RF electrode cluster, and cryoablation probe, respectively. Mean minimum and maximum lesion diameters were largest with the RF electrode cluster (2.40 and 3.98 cm, respectively), followed by the cryoablation probe (2.38 and 3.94 cm) and single RF electrode (1.49 and 2.63 cm). Mean minimum and maximum lesion diameters were significantly different between the single RF electrode and the RF electrode cluster, as well as between the single RF electrode and the cryoablation probe (P < .001). Mean lesion volume was largest for the RF electrode cluster (24.03 cm3), followed by those for the cryoablation probe (17.46 cm3) and single RF electrode (9.05 cm3) (single RF electrode vs cryoablation probe, P < .05). Lesion volumes were not significantly different with the RF electrode cluster versus the single RF electrode (P = .052) or with the RF electrode cluster versus the cryoablation probe (P = .381). Mean blood loss from percutaneous cryoablation in this model was between that for RF ablation with the single electrode and that for RF ablation with the electrode cluster.

Enlarging vertebrobasilar nonsaccular intracranial aneurysms: frequency, predictors, and clinical outcome of growth

Vertebrobasilar nonsaccular intracranial aneurysms (NIAs) are characterized by elongation, dilation, and tortuosity of the vertebrobasilar arteries. The goal of this study was to define the frequency, predictors, and clinical outcome of the enlargement of vertebrobasilar NIAs. Patients with vertebrobasilar fusiform or dolichoectatic aneurysms demonstrated on imaging studies between 1989 and 2001 were identified. In particular, patients who had undergone serial imaging were included in this study and their medical records were retrospectively reviewed. Prospective information was collected from medical records or death certificates when available. Both initial and serial imaging studies were reviewed. The authors defined NIA enlargement as a change in lesion diameter greater than 2 mm or noted on the neuroradiologist's report. A Cox proportional hazards regression was used to model time from diagnosis of the vertebrobasilar NIA to the first documented enlargement as a function of various predictors. The Kaplan-Meier method was used to study patient death as a function of aneurysm growth. Of the 159 patients with a diagnosis of vertebrobasilar NIA, 52 had undergone serial imaging studies including 25 patients with aneurysm enlargement. Lesion growth significantly correlated with symptomatic compression at the initial diagnosis (p = 0.0028), lesion type (p < 0.001), and the initial maximal lesion diameter (median 15 mm in patients whose aneurysm enlarged compared with median 8 mm in patients whose aneurysm did not enlarge; p < 0.001). The mortality rate was 5.7 times higher in patients with aneurysm growth than in those with no enlargement after adjustment for patient age (p = 0.002). Forty-eight percent of vertebrobasilar NIAs demonstrated on serial imaging enlarged, and this growth was associated with significant morbidity and death. Significant risk factors for aneurysm enlargement included symptomatic compression at the initial diagnosis, transitional or fusiform vertebrobasilar NIAs, and initial lesion diameter. Further studies are necessary to determine appropriate treatments of this disease entity once enlargement has been predicted or occurs.

Assessment of response to induction therapy and its influence on 5-year failure-free survival (FFS) in Group III rhabdomyosarcoma (RMS): Intergroup Rhabdomyosarcoma Study (IRS)-IV experience

8513 Background: Initial response to induction chemotherapy (CT) predicts FFS in osteosarcoma and Ewing sarcoma. Current European studies in RMS tailor therapy based on induction response. For IRS IV subjects with Group III RMS, we assessed whether reported response to induction therapy predicted FFS. Methods: We studied 453 Group III subjects who received induction CT, had response assessed at week 8 and continued with protocol therapy. Induction CT was followed by radiation therapy (RT) starting after week 9. Response to induction therapy was determined by radiographic measurement of tumor at weeks 0 and 8. Complete response (CR: complete resolution of disease), partial response (PR: ≥ 50% decrease in the sum of the products of the maximum perpendicular diameters of measurable lesions), no response (NR: < 50% decrease and < 25% increase), or progressive disease (>25% increase) was coded by local institutions. Results: Response rate at week 8 was 77% (CR=21%, PR=56%) but response had no influence on FFS (p=0.89). 272 subjects received only CT during induction. Response rate was 81% (CR=22%, PR=59%) and was independent of histology and tumor size. In these subjects, response did not influence FFS except for those with alveolar histology. 141 other subjects received CT and RT during induction, usually because of a parameningeal primary with intracranial extension. Response rate was 65% (CR=12%, PR=53%) but response had no influence on FFS. 40 subjects received no RT at all (protocol violation) and response to induction CT had no effect on FFS. Conclusion: In IRS IV, response rate to induction therapy was 77% in Group III subjects but induction response had no influence on FFS overall. Table 1. Response rate and FFS by induction therapy and histology No significant financial relationships to disclose.

Assessment of response to induction therapy and its influence on 5-year failure-free survival (FFS) in Group III rhabdomyosarcoma (RMS): Intergroup Rhabdomyosarcoma Study (IRS)-IV experience

8513 Background: Initial response to induction chemotherapy (CT) predicts FFS in osteosarcoma and Ewing sarcoma. Current European studies in RMS tailor therapy based on induction response. For IRS IV subjects with Group III RMS, we assessed whether reported response to induction therapy predicted FFS. Methods: We studied 453 Group III subjects who received induction CT, had response assessed at week 8 and continued with protocol therapy. Induction CT was followed by radiation therapy (RT) starting after week 9. Response to induction therapy was determined by radiographic measurement of tumor at weeks 0 and 8. Complete response (CR: complete resolution of disease), partial response (PR: ≥ 50% decrease in the sum of the products of the maximum perpendicular diameters of measurable lesions), no response (NR: 25% increase) was coded by local institutions. Results: Response rate at week 8 was 77% (CR=21%, PR=56%) but response had no influence on FFS ...

Sonographic assessment of extent and aggressiveness of malignant breast disease

Sonographic assessment of extent and aggressiveness of malignant breast disease

Natural history of pancreatic intraductal papillary mucinous tumor of branch duct type: follow-up study by magnetic resonance cholangiopancreatography.

The purpose of this study was to elucidate the natural history of branch duct type pancreatic intraductal papillary mucinous tumor (IPMT) by evaluating serial changes in the magnetic resonance cholangiopancreatography (MRCP) findings of patients diagnosed with pancreatic IPMT of branch duct type. Thirty-five patients had branch duct type IPMT, including 9 patients with separate lesions, and underwent initial and follow-up MRCP over a period of more than 12 months. The maximum diameter of the cystic lesion, the presence of associated main pancreatic duct (MPD) dilatation, and the presence of a filling defect were evaluated. Serial changes in these findings were analyzed. Tumor enlargement on follow-up MRCP was observed in 7 cases. Of the 29 branch duct IPMTs without associated MPD dilatation or a filling defect identified on initial MRCP, only 1 showed gradual tumor enlargement. In 4 cases, the cyst size decreased on follow-up MRCP. Branch duct type IPMTs grow slowly and can be monitored without operation provided that the tumor shows no associated MPD dilatation or filling defect.

Natural History of Renal Masses Followed Expectantly

An increasing number of incidental renal masses have been detected with increasing use of ultrasonography, computerized tomography and magnetic resonance imaging. We investigated the natural history of incidentally detected renal masses. A total of 24 patients were included in this retrospective analysis. Average patient age was 68.3 years (range 29 to 83). The 16 males and 8 females were followed with abdominal imaging for a mean and median followup of 31.6 and 24 months, respectively (range 8 to 86). Patients elected to be observed because of age, poor medical condition or the presence of a mass in a solitary kidney. The majority of patients (22 of 24) were asymptomatic at diagnosis. Two patients were followed with bilateral renal masses, and 2 with T3b tumors. Of the 20 patients with incidental solitary renal masses, 6 were at the upper pole, 9 were mid polar and 5 lower pole. Mean maximum diameter of lesions was 3.3 cm (median 2.7, range 0.9 to 10). Growth rate was calculated based on diameter and tumor volume. Of the 24 patients only 5 demonstrated tumor growth during the surveillance period. No metastasis developed in any patients. Mean tumor growth rate observed in the 5 patients was 0.49 cm per year or 7.3 cc per year. Of the 24 patients 4 underwent surgery after surveillance because of apparent tumor growth or per patient request. Pathology revealed renal cell carcinoma in all 4. Tumor growth of renal masses is often limited. Most of our patients did not demonstrate significant growth when followed expectantly. Without tumor growth the risk of metastasis seems limited.

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.

Combined Radiofrequency Ablation and Hot Saline Injection in Rabbit Liver

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. 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. 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). 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.

Management of splenic artery aneurysms and false aneurysms with endovascular treatment in 12 patients.

To assess the endovascular treatment of splenic artery aneurysms and false aneurysms. Twelve patients (mean age 59 years, range 47-75 years) with splenic artery aneurysm (n = 10) or false aneurysm (n = 2) were treated. The lesion was asymptomatic in 11 patients; hemobilia was observed in one patient. The lesion was juxta-ostial in one case, located on the intermediate segment of the splenic artery in four, near the splenic hilus in six, and affected the whole length of the artery in one patient. In 10 cases, the maximum lesion diameter was greater than 2 cm; in one case 30% growth of an aneurysm 18 mm in diameter had occurred in 6 months; in the last case, two distal aneurysms were associated (17 and 18 mm in diameter). In one case, stent-grafting was attempted; one detachable balloon occlusion was performed; the 10 other patients were treated with coils. Endovascular treatment was possible in 11 patients (92%) (one failure: stenting attempt). In four cases among 11, the initial treatment was not successful (residual perfusion of aneurysm); surgical treatment was carried out in one case, and a second embolization in two. Thus in nine cases (75%) endovascular treatment was successful: complete and persistent exclusion of the aneurysm but with spleen perfusion persisting at the end of follow-up on CT scans (mean 13 months). An early and transient elevation of pancreatic enzymes was observed in four cases. Ultrasound and CT have made the diagnosis of splenic artery aneurysm or false aneurysm more frequent. Endovascular treatment, the morbidity of which is low, is effective and spares the spleen.

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.