Strategies for successful integration of work from home faculty in an academic radiology department

Academic radiology departments have added increasing numbers of entirely remote "work-from-home" or hybrid faculty. This change has presented both an opportunity to recruit and retain faculty as well as a set of challenges to maintaining the full academic mission and educational environment. In this article we describe our experience with creating a remote faculty position and the key elements that we believe made it successful. Guiding principles for the department and faculty member accepting such a position are proposed and discussed.

Physician Knowledge of Radiation Exposure and Risk in Medical Imaging

PURPOSE

Medical imaging is an increasingly important source of radiation exposure for the general population, and there are risks associated with such exposure; however, recent studies have demonstrated poor understanding of medical radiation among various groups of health care providers. This study had two aims: (1) analyze physicians' knowledge of radiation exposure and risk in diagnostic imaging across multiple specialties and levels of training, and (2) assess the effectiveness of a brief educational presentation on improving physicians' knowledge.

METHODS

From 2014 to 2016, 232 health care providers from multiple departments participated in an educational presentation and pre- and postpresentation tests evaluating knowledge of radiation exposure and risk at a large academic institution.

RESULTS

Knowledge of radiation exposure and risk was relatively low on the prepresentation test, including particularly poor understanding of different imaging modalities, with 26% of participants unable to correctly identify which modalities expose patients to ionizing radiation. Test scores significantly increased after the educational presentation. Radiologists had higher prepresentation test scores than other specialties, and therefore less opportunity for improvement, but also demonstrated improvement in radiation safety knowledge after education. Aside from radiology, there was no significant difference in initial knowledge of radiation exposure and risk among the other specialties.

CONCLUSIONS

Providers' knowledge of radiation exposure and risk was low at baseline but significantly increased after a brief educational presentation. Efforts to educate ordering providers about radiation exposure and risk are needed to ensure that providers are appropriately weighing the risks and benefits of medical imaging and to ensure high-quality, patient-centered care.

The prediction of radiofrequency ablation zone volume using vascular indices of 3-dimensional volumetric colour Doppler ultrasound in an in vitro blood-perfused bovine liver model

OBJECTIVE

To determine the most reliable predictor of radiofrequency (RF) ablation zone volume among three-dimensional (3D) volumetric colour Doppler vascular indices in an in vitro blood-perfused bovine liver model.

METHODS

3D colour Doppler volume data of the local hepatic parenchyma were acquired from 37 areas of 13 bovine livers connected to an in vitro oxygenated blood perfusion system. Doppler vascular indices of vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were obtained from the volume data using 3D volume analysis software. 37 RF ablations were performed at the same locations where the ultrasound data were obtained from. The relationship of these vascular indices and the ablation zone volumes measured from gross specimens were analyzed using a general linear mixed model fit with random effect for liver and backward stepwise regression analysis.

RESULTS

FI was significantly associated with ablation zone volumes measured on gross specimens (p = 0.0047), but explained little of the variance (R_β² = 0.21). Ablation zone volume decreased by 0.23 cm³ (95% confidence interval: -0.38, -0.08) for every 1 increase in FI. Neither VI nor VFI was significantly associated with ablation zone volumes (p > 0.05).

CONCLUSION

Although FI was associated with ablation zone volumes, it could not sufficiently explain their variability, limiting its clinical applicability. VI, FI and VFI are not clinically useful in the prediction of RF ablation zone volume in the liver. Advances in knowledge: Despite a significant association of FI with ablation zone volumes, VI, FI and VFI cannot be used for their prediction. Different Doppler vascular indices need to be investigated for clinical use.

Reengineering the radiology enterprise: a summary of the 2014 Intersociety Committee Summer Conference

The current initiative to reform health care from both a quality and a cost perspective has already had a profound impact on the radiology enterprise. We have seen a decrease in the utilization of imaging studies, a reduction in reimbursement, a declining payer mix, shrinking incomes, a proliferation of performance indices, creation of radiology mega-groups, growth of national radiology companies, and increasing turf incursions. Our cheese is clearly on the move, and we must take action to reengineer the radiology enterprise. In keeping with general health care reform, we must be patient-centric, data driven, and outcome based. We must create a radiology enterprise that adheres to the value equation of providing the highest quality health care, for the lowest possible cost, for all citizens.

Effect of Change in Portal Venous Blood Flow Rates on the Performance of a 2.45-GHz Microwave Ablation Device

PURPOSE

To investigate the effect of change in portal venous blood flow rates on the size and shape of ablations created by a 2.45-GHz microwave ablation device.

MATERIALS AND METHODS

This study was exempt from review by the institutional animal care and use committee. An in vitro bovine liver model perfused with autologous blood via the portal vein at five flow rates (60, 70, 80, 90, and 100 mL/min per 100 g of liver) was used to evaluate the effect of change in flow rates on the size and shape of coagulation created by a 2.45-GHz, 140-W microwave ablation device operated for 5 and 10 minutes. Three ablations per ablation time were conducted in each of 10 livers, with two livers perfused at each flow rate. Short- and long-axis diameters were measured from gross specimens, and volume and sphericity index were calculated. General linear mixed models that accounted for correlations within the liver were used to evaluate the effects of lobe, flow, and ablation time on size and sphericity index of ablations.

RESULTS

Flow did not have a significant effect on the size or shape of coagulation created at 5 or 10 minutes (P > .05 for all tests). The mean short- and long-axis diameters and volume were 3.2 cm (95% confidence interval [CI]: 3.1, 3.3), 5.6 cm (95% CI: 5.4, 5.8), and 30.2 cm(3) (95% CI: 28.4, 32.1) for the 5-minute ablations and 3.8 cm (95% CI: 3.7, 3.9), 6.5 cm (95% CI: 6.3, 6.7), and 49.3 cm(3) (95% CI: 47.5, 51.2), for the 10-minute ablations, respectively. The mean sphericity index for both 5- and 10-minute ablations was 34.4% (95% CI: 32%, 36.7%).

CONCLUSION

Change in portal venous blood flow rates did not have an effect on the size and shape of ablations created by a 2.45-GHz microwave ablation device.

Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes.

The design and fabrication of two portal vein flow phantoms by different methods

PURPOSE

This study outlines the design and fabrication techniques for two portal vein flow phantoms.

METHODS

A materials study was performed as a precursor to this phantom fabrication effort and the desired material properties are restated for continuity. A three-dimensional portal vein pattern was created from the Visual Human database. The portal vein pattern was used to fabricate two flow phantoms by different methods with identical interior surface geometry using computer aided design software tools and rapid prototyping techniques. One portal flow phantom was fabricated within a solid block of clear silicone for use on a table with Ultrasound or within medical imaging systems such as MRI, CT, PET, or SPECT. The other portal flow phantom was fabricated as a thin walled tubular latex structure for use in water tanks with Ultrasound imaging. Both phantoms were evaluated for usability and durability.

RESULTS

Both phantoms were fabricated successfully and passed durability criteria for flow testing in the next project phase.

CONCLUSIONS

The fabrication methods and materials employed for the study yielded durable portal vein phantoms.

Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. Online supplemental material is available for this article .

An investigation of industrial molding compounds for use in 3D ultrasound, MRI, and CT imaging phantoms

PURPOSE

This study investigated the ultrasound, MRI, and CT imaging characteristics of several industrial casting and molding compounds as a precursor to the future development of durable and anatomically correct flow phantoms.

METHODS

A set of usability and performance criteria was established for a proposed phantom design capable of supporting liquid flow during imaging. A literature search was conducted to identify the materials and methods previously used in phantom fabrication. A database of human tissue and casting material properties was compiled to facilitate the selection of appropriate materials for testing. Several industrial casting materials were selected, procured, and used to fabricate test samples that were imaged with ultrasound, MRI, and CT.

RESULTS

Five silicones and one polyurethane were selected for testing. Samples of all materials were successfully fabricated. All imaging modalities were able to discriminate between the materials tested. Ultrasound testing showed that three of the silicones could be imaged to a depth of at least 2.5 cm (1 in.). The RP-6400 polyurethane exhibited excellent contrast and edge detail for MRI phantoms and appears to be an excellent water reference for CT applications. The 10T and 27T silicones appear to be usable water references for MRI imaging.

CONCLUSIONS

Based on study data and the stated selection criteria, the P-4 silicone provided sufficient material contrast to water and edge detail for use across all imaging modalities with the benefits of availability, low cost, dimensional stability, nontoxic, nonflammable, durable, cleanable, and optical clarity. The physical and imaging differences of the materials documented in this study may be useful for other applications.

Percutaneous radiofrequency ablation of symptomatic giant hepatic cavernous hemangiomas: report of two cases and review of literature

The presented cases detail percutaneous radiofrequency (RF) ablation of multiple giant hepatic hemangiomas in two patients who presented with right upper-quadrant pain and fullness and chose not to undergo surgical resection. Treatment of two hemangiomas per patient, 7 cm and 6 cm in one and 9 cm and 2 cm in the other, was accomplished in single ablation sessions with 12 and nine cycles, respectively. Patients had durable resolution of symptoms with reduction of lesion size by 68%-82% at a mean follow-up of 13 months. These cases, along with promising results in the current literature, support RF ablation as a safe and effective surgical alternative.

Chemoradionuclide therapy with 186Re-labeled liposomal doxorubicin in combination with radiofrequency ablation for effective treatment of head and neck cancer in a nude rat tumor xenograft model

PURPOSE

To determine the therapeutic efficacy of rhenium 186 ((186)Re)-labeled PEGylated liposomal doxorubicin ((186)Re-liposomal doxorubicin) in combination with radiofrequency (RF) ablation of human head and neck squamous cell carcinoma (HNSCC) xenograft in nude rats.

MATERIALS AND METHODS

This investigation was approved by the animal care committee. Sixty nude rats with subcutaneously implanted HNSCC xenografts (six per group) were treated with (a) RF ablation (70 °C for 5 minutes), (b) PEGylated liposomes, (c) liposomal doxorubicin, (d) (186)Re-PEGylated liposomes (1295 MBq/kg), (e) (186)Re-liposomal doxorubicin (555 MBq/kg), (f) PEGylated liposomes plus RF ablation, (g) liposomal doxorubicin plus RF ablation, (h) (186)Re-PEGylated liposomes plus RF ablation, or (i) (186)Re-liposomal doxorubicin plus RF ablation. Six rats did not receive any treatment (control group). Tumor uptake in (186)Re therapy groups was monitored with small-animal single photon emission computed tomography for 5 days. Therapeutic efficacy was monitored for 6 weeks with measurement of tumor volume, calculation of the percentage injected dose of fluorine 18 fluorodeoxyglucose (FDG) in tumor from small-animal positron emission tomography (PET) images, and determination of viable tumor volume at histopathologic examination. Significant differences between groups were determined with analysis of variance.

RESULTS

The average tumor volume (± standard deviation) on the day of therapy was 1.32 cm(3) ± 0.17. At 6 weeks after therapy, control of tumor growth was better with (186)Re-liposomal doxorubicin than with liposomal doxorubicin alone (tumor volume, 2.26 cm(3) ± 0.89 vs 5.43 cm(3) ± 0.93, respectively; P < .01). The use of RF ablation with liposomal doxorubicin and (186)Re-liposomal doxorubicin further improved tumor control (tumor volume, 2.05 cm(3) ± 1.36 and 1.49 cm(3) ± 1.47, respectively). The tumor growth trend correlated with change in percentage of injected dose of FDG in tumor for all groups (R(2) = 0.85, P < .001). Viable tumor volume was significantly decreased in the group treated with (186)Re-liposomal doxorubicin plus RF ablation (0.54 cm(3) ± 0.38; P < .001 vs all groups except (186)Re-liposomal doxorubicin alone).

CONCLUSION

Triple and dual therapies had an observable trend ((186)Re-liposomal doxorubicin plus RF ablation > (186)Re-liposomal doxorubicin > liposomal doxorubicin plus RF ablation > liposomal doxorubicin) of improved tumor growth control and decreased viable tumor compared with other therapies. FDG PET could be used as a noninvasive surrogate marker for tumor growth and viability in this tumor model.

High-fidelity computer models for prospective treatment planning of radiofrequency ablation with in vitro experimental correlation

PURPOSE

To evaluate the accuracy of computer simulation in predicting the thermal damage region produced by a radiofrequency (RF) ablation procedure in an in vitro perfused bovine liver model. The thermal dose end point in the liver model is used to assess quantitatively computer prediction for use in prospective treatment planning of RF ablation procedures.

MATERIALS AND METHODS

Geometric details of the tri-cooled tip electrode were modeled. The resistive heating of a pulsed voltage delivery was simulated in four dimensions using finite element models (FEM) implemented on high-performance parallel computing architectures. A range of physically realistic blood perfusion parameters, 3.6-53.6 kg/sec/m(3), was considered in the computer model. An Arrhenius damage model was used to predict the thermal dose. Dice similarity coefficients (DSC) were the metric of comparison between computational predictions and T1-weighted contrast-enhanced images of the damage obtained from a RF procedure performed on an in vitro perfused bovine liver model.

RESULTS

For a perfusion parameter greater than 16.3 kg/sec/m(3), simulations predict the temporal evolution of the damaged volume is perfusion limited and will reach a maximum value. Over a range of physically meaningful perfusion values, 16.3-33.1 kg/sec/m(3), the predicted thermal dose reaches the maximum damage volume within 2 minutes of the delivery and is in good agreement (DSC > 0.7) with experimental measurements obtained from the perfused liver model.

CONCLUSIONS

As measured by the computed volumetric DSC, computer prediction accuracy of the thermal dose shows good correlation with ablation lesions measured in vitro in perfused bovine liver models over a range of physically realistic perfusion values.

Combination radiofrequency ablation and intravenous radiolabeled liposomal Doxorubicin: imaging and quantification of increased drug delivery to tumors

PURPOSE

To identify, with noninvasive imaging, the zone of radiopharmaceutical uptake after combination therapy with radiofrequency (RF) ablation and intravenous administration of technetium 99m ((99m)Tc) liposomal doxorubicin in a small-animal tumor model, and to quantify and correlate the uptake by using imaging and tissue counting of intratumoral doxorubicin accumulation.

MATERIALS AND METHODS

This study was approved by the animal care committee. Two phases of animal experiments were performed. In the first experiment, a single human head-and-neck squamous cell carcinoma tumor was grown in each of 10 male nude rats. Seven of these animals were treated with intravenous (99m)Tc-liposomal doxorubicin followed by RF tumor ablation at a mean temperature of 70 degrees C + or - 2 for 5 minutes, and three were treated with intravenous (99m)Tc-liposomal doxorubicin only. Combination single photon emission computed tomography-computed tomography (SPECT/CT) was performed at 15 minutes, 4 hours, and 20 hours after therapy. In the second experiment, two tumors each were grown in 11 rats, but only one of the tumors was ablated after intravenous administration of (99m)Tc-liposomal doxorubicin. SPECT/CT and planar scintigraphy were performed at the same posttreatment intervals applied in the first experiment, with additional planar imaging performed at 44 hours. After imaging, tissue counting in the excised tumors was performed. Radiotracer uptake, as determined with imaging and tissue counting, was quantified and compared. In a subset of three animals, intratumoral doxorubicin accumulation was determined with fluorimetry and correlated with the imaging and tissue-counting data.

RESULTS

At both SPECT/CT and planar scintigraphy, increased uptake of (99m)Tc-liposomal doxorubicin was visibly apparent in the ablated tumors. Results of quantitative analysis with both imaging and tissue counting confirmed significantly greater uptake in the RF ablation-treated tumors (P < .001). Intratumoral doxorubicin accumulation correlated closely with imaging (r = 0.9185-0.9871) and tissue-counting (r = 0.995) results.

CONCLUSION

Study results show that increased delivery of intravenous liposomal doxorubicin to tumors combined with RF ablation can be depicted and quantified with noninvasive imaging.

American Society of Clinical Oncology 2009 clinical evidence review on radiofrequency ablation of hepatic metastases from colorectal cancer

PURPOSE

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).

METHODS

The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.

RESULTS

Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.

CONCLUSION

There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Image-guided tumor ablation: standardization of terminology and reporting criteria

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

Percutaneous radiofrequency ablation of hepatic tumors against the diaphragm: frequency of diaphragmatic injury

PURPOSE

To retrospectively determine the frequency of diaphragmatic injury when percutaneous hepatic radiofrequency (RF) ablation is performed adjacent to the diaphragm.

MATERIALS AND METHODS

Institutional Review Board approval was obtained for our HIPAA-compliant study. Informed consent for the ablation procedure and for use of related data for future research was obtained from each patient. A retrospective review was conducted of 215 patients undergoing percutaneous RF ablation of hepatic tumors. Twenty-nine patients (21 men and eight women; age, 41-89 years) were identified with tumors abutting the diaphragm. Episodes of right shoulder pain were recorded. A panel of radiologists blinded to the patients' clinical histories reviewed their imaging for evidence of diaphragmatic injury and ablation success. A generalized estimating equation model and the Fisher exact test were used for statistical analysis.

RESULTS

The 29 patients had a total of 33 tumors abutting the diaphragm. Tumor size was 1.3-5.5 cm (mean, 3.2 cm +/- 1.1). After ablation, five (17%) patients reported right shoulder pain. In four, pain was mild or moderate, with symptoms lasting 2-14 days (median, 5.5 days). Three of these showed diaphragmatic thickening on postablation computed tomographic (CT) scans. One patient had severe pain lasting 2 weeks, followed by milder pain for 2 months. This patient's postablation CT images showed focal nodular diaphragmatic thickening. This patient was treated with a multitined device; the other four, with straight-needle devices. Local tumor progression was seen in 14 tumors (42.4%). Tumors 3 cm or smaller had a much lower local progression rate than tumors larger than 3 cm (12.5% vs 70.6%).

CONCLUSION

Of 29 patients who had ablation of hepatic tumors adjacent to the diaphragm, five (17%) had diaphragmatic injury, which was clinically apparent with right shoulder pain.

The Crisis in Academic Radiology: Will We Help Ourselves?

The overall health of academic radiology suffers from insufficient funds and manpower. Although the largest academic programs in the country may have sufficient resources to maintain robust academic environments, one third to half of the academic radiology programs in the United States are struggling to maintain stable academic environments. The impact of an impaired academic radiology enterprise on the specialty of radiology is far reaching. As academic departments falter, the quantity and quality of research and educational programs deteriorate. In the short term, this situation makes our specialty vulnerable to predatory strikes by other specialists who covet our field; in the long term, it leads to obsolescence. Fortunately, radiology is a lucrative specialty, and we have the wherewithal to help ourselves. To ensure a vibrant future for our specialty each of us must accept an obligation to invest in our academic foundation. In particular, private practice radiologists must recognize this obligation and pledge their time and/or resources to help shore up the academic departments.

A genomewide search finds major susceptibility loci for gallbladder disease on chromosome 1 in Mexican Americans

Gallbladder disease (GBD) is one of the major digestive diseases. Its risk factors include age, sex, obesity, type 2 diabetes, and metabolic syndrome (MS). The prevalence of GBD is high in minority populations, such as Native and Mexican Americans. Ethnic differences, familial aggregation of GBD, and the identification of susceptibility loci for gallstone disease by use of animal models suggest genetic influences on GBD. However, the major susceptibility loci for GBD in human populations have not been identified. Using ultrasound-based information on GBD occurrence and a 10-cM gene map, we performed multipoint variance-components analysis to localize susceptibility loci for GBD. Phenotypic and genotypic data from 715 individuals in 39 low-income Mexican American families participating in the San Antonio Family Diabetes/Gallbladder Study were used. Two GBD phenotypes were defined for the analyses: (1) clinical or symptomatic GBD, the cases of cholecystectomies due to stones confirmed by ultrasound, and (2) total GBD, the clinical GBD cases plus the stone carriers newly diagnosed by ultrasound. With use of the National Cholesterol Education Program/Adult Treatment Panel III criteria, five MS risk factors were defined: increased waist circumference, hypertriglyceredemia, low high-density lipoprotein cholesterol, hypertension, and high fasting glucose. The MS risk-factor score (range 0-5) for a given individual was used as a single, composite covariate in the genetic analyses. After accounting for the effects of age, sex, and MS risk-factor score, we found stronger linkage signals for the symptomatic GBD phenotype. The highest LOD scores (3.7 and 3.5) occurred on chromosome 1p between markers D1S1597 and D1S407 (1p36.21) and near marker D1S255 (1p34.3), respectively. Other genetic locations (chromosomes 2p, 3q, 4p, 8p, 9p, 10p, and 16q) across the genome exhibited some evidence of linkage (LOD >or=1.2) to symptomatic GBD. Some of these chromosomal regions corresponded with the genetic locations of Lith loci, which influence gallstone formation in mouse models. In conclusion, we found significant evidence of major genetic determinants of symptomatic GBD on chromosome 1p in Mexican Americans.

Image-guided tumor ablation: standardization of terminology and reporting criteria

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

Percutaneous Radiofrequency Ablation of Hepatic Tumors: Postablation Syndrome

OBJECTIVE

Our objective was to define the spectrum and possible predictors of symptoms that occur in patients after percutaneous radiofrequency ablation of hepatic tumors.

SUBJECTS AND METHODS

We performed 50 consecutive percutaneous radiofrequency ablation sessions on 39 patients with a total of 89 liver tumors. All patients had pre- and postablation laboratory studies and CT or MRI scans. After treatment, patients were followed for 3 weeks with a standardized questionnaire to assess for postablation symptoms. Comparisons of the presence or absence of symptoms were made for the laboratory test values, liver volumes, and pre- and postablation tumor volumes.

RESULTS

Postablation symptoms occurred in 14 of 39 (36%) patients after 17 of 50 (34%) ablation sessions. Symptoms consisted of fever (16/17), malaise (12/17), chills (6/17), delayed pain (5/17), and nausea (2/17). On average, the symptoms presented 3 days after ablation and lasted 5 days. Statistically significant (p < 0.01) predictors of symptoms were tumor volumes > 50 cm3 (4.5 cm diameter), ablated tissue volumes > 150 cm3 (6.5 cm diameter), a difference between preablation tumor volume and the volume of tissue ablated > 125 cm3, or postablation aspartate aminotransferase levels > 350 IU/L.

CONCLUSION

Approximately one third of patients undergoing percutaneous radiofrequency ablation of hepatic tumors develop delayed, transient flulike symptoms that can be treated conservatively and are significantly related to the volume of tissue ablated. Familiarity with this postablation syndrome should facilitate appropriate management of affected patients.

Image-guided tumor ablation: standardization of terminology and reporting criteria

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency, laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes.

Thermal ablation for hepatocellular carcinoma

Thermal ablation, as a form of minimally invasive therapy for hepatocellular carcinoma (HCC), has become an important treatment modality. Because of the limitations of surgery, the techniques of thermal ablation have become standard therapies for HCC in some situations. This article reviews 4 thermal ablation techniques-radiofrequency (RF) ablation, microwave ablation, laser ablation, and cryoablation. Each of these techniques may have a role in treating HCC, and the mechanisms, equipment, patient selection, results, and complications of each are considered. Furthermore, combined therapies consisting of thermal ablation and adjuvant chemotherapy also show promise for enhancing these techniques. Important areas of research into thermal ablation remain, including improving the ability of ablation to treat larger tumors, determining the indications for each thermal ablation modality, optimizing image guidance, and obtaining good outcome data on the efficacy of these techniques.

Radiofrequency thermal ablation of abdominal tumors: lessons learned from complications

Radiofrequency (RF) thermal ablation has shown promise as a technique for treating inoperable solid tumors involving the liver, kidney, adrenal gland, and lung. However, like all other imaging-guided interventional procedures, RF ablation involves some element of risk. Varying degrees of complications can be expected, depending on factors such as the organ site and the aggressiveness of the procedure. General complications of RF ablation may be related to either imaging-guided electrode placement (eg, bleeding, infection, tumor seeding, pneumothorax) or thermal therapy (eg, nontarget thermal damage, grounding pad burns). Liver and renal-adrenal ablation may be associated with organ-specific complications. A fundamental understanding of RF ablation principles, along with adequate operator training and experience and familiarity with both thermal ablation and the broad spectrum of postablation complications, are necessary to maximize the safety and efficacy of this procedure. The standard of care for decreasing the morbidity of complications consists of prevention (including careful patient selection), early detection, and prompt, appropriate treatment.

Frequency and CT patterns of bowel wall thickening proximal to cancer of the colon

OBJECTIVE

This study was performed to determine the frequency and patterns of colon wall thickening seen on CT of patients with adenocarcinoma of the colon.

MATERIALS AND METHODS

Preoperative abdominal and pelvic CT scans of 185 patients with surgically proven adenocarcinoma of the colon were retrospectively evaluated by three abdominal radiologists for the presence of colon obstruction and colon wall thickening proximal to the colon adenocarcinoma. The distributions and patterns of colon wall thickening were categorized by consensus. CT findings were compared with pathologic findings. Fisher's exact test was used to determine the statistical significance of any associations.

RESULTS

Of 185 patients, CT findings of 20 (10.8%) showed colon wall thickening. Of these, the adenocarcinoma obstructed the colon in 19 patients (p < 0.01). Colon obstruction was partial in 10 patients (53%) and complete in nine (47%). Colon wall thickening was contiguous to the tumor in 14 (70%) patients and noncontiguous in six (30%). Segmental and pancolonic, patchy and diffuse, and dependent and nondependent colon wall thickening was observed in 10 patients (50%) in each category. Associated small-bowel wall thickening was shown in 10 (50%) of the 20 patients. Pathologic examination showed colon wall thickening to be due to edema in all cases.

CONCLUSION

Colon wall edema can occur proximal to colon adenocarcinoma, is almost always associated with colon obstruction, and is predominantly contiguous with the obstructing adenocarcinoma.

Radiofrequency Ablation of Hepatic Tumors: Variability of Lesion Size Using a Single Ablation Device

OBJECTIVE

In this study, we examined the variability of lesion sizes produced by a single radiofrequency ablation using the same device and algorithm in patients with small malignant hepatic tumors.

MATERIALS AND METHODS

A review of the clinical records of 208 patients who underwent radiofrequency ablation of malignant hepatic tumors during a 6-year period revealed 31 patients with small tumors that were treated with a single ablation. Clinical data were recorded using standardized work sheets. Tumor and lesion sizes after ablation were measured from CT scans. The influences of tumor size, tumor type, presence or absence of cirrhosis, and tissue temperature on the ablation size were analyzed.

RESULTS

The size of tumor before treatment ranged from 0.8 to 4.0 cm (mean diameter [+/- SD] = 1.8 +/- 0.9 cm) with corresponding volumes of 0.27-30.24 mL (mean volume = 27.1 +/- 15.9 mL). The lesion sizes after ablation ranged from 1.7 to 5.3 cm (mean diameter = 3.6 +/- 0.7 cm) with corresponding volumes of 2.29-75.87 mL (mean volume = 4.9 +/- 7.1 mL). Tumor type (p > 0.25), presence or absence of cirrhosis (p > 0.45), and tissue temperature (p = 0.055) had no relationship to ablation size. Tumor size had a statistically significant influence on ablation lesion size (p < 0.04). Ablation of small tumors (diameter < or = 2.25 cm, n = 32) produced random lesion sizes whereas ablation of large tumors (diameter > 2.25 cm, n = 11) produced larger lesions (mean diameter = 4.0 +/- 0.8 cm).

CONCLUSION

Significant variation occurs in the lesion size produced using the same ablation device and algorithm. These findings must be considered when planning ablation strategies.

Image-guided tumor ablation: proposal for standardization of terms and reporting criteria

The field of image-guided tumor ablation requires standardization of terms and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments with different technologies, such as chemical ablation (ethanol or acetic acid) and thermal therapies, such as radiofrequency, laser, microwave, ultrasound, and cryoablation. On the basis of this premise, a working committee was established with the goal of producing a proposal on such standardization. The intent of the Working Group is to provide a framework that will facilitate the clearest communication between investigators and will provide the greatest flexibility in comparisons between the many new, exciting, and emerging technologies. The members of the Working Group now propose a vehicle for reporting the various aspects of image-guided ablation therapy, including classifications of therapies and procedures, appropriate descriptors of image guidance, and terms to define imaging and pathologic findings. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's hope and intention that adherence to the recommendations of this proposal will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and ultimately to improved patient outcomes.

Radiofrequency tissue ablation: effect of hepatic blood flow occlusion on thermal injuries produced in cirrhotic livers

BACKGROUND

Radiofrequency thermal ablation has been used as a treatment for several types of hepatic malignancies. Many of these lesions exist in the presence of cirrhosis. Limitations exist to the size of the ablations and, subsequently, the efficacy of treatment. Hepatic vascular inflow occlusion has been advocated as an adjunctive measure to increase the efficacy of the ablation. We present a model in the human cirrhotic liver that demonstrates the advantage of blood flow occlusion during radiofrequency ablation.

METHODS

Five patients with advanced endstage liver disease scheduled to have orthotopic liver transplantation were enrolled in this study. After laparotomy and before hepatectomy, radiofrequency ablation was performed without and with hepatic blood flow occlusion. After hepatectomy, the liver was sectioned, the area of ablation was measured in three dimensions, and the volume of ablation calculated.

RESULTS

Three of the patients had had previously placed transjugular intrahepatic portosystemic shunt. The mean volume of the ablation without blood flow occlusion was 22.5 +/- 7.4 cm(3) and that with blood flow occlusion was 48.4 +/- 24.0 cm(3) (P =.05).

CONCLUSIONS

Ablation area is increased significantly with hepatic blood flow occlusion in the human cirrhotic liver. This result may have application in the treatment of larger (>3 cm) hepatic malignancies.

Radiofrequency ablation of hepatic tumors adjacent to the gallbladder: feasibility and safety

OBJECTIVE

This study was performed to assess the feasibility and safety of radiofrequency ablation of hepatic tumors adjacent to the gallbladder.

MATERIALS AND METHODS

Of the 83 patients who underwent radiofrequency ablation of hepatic tumors at our institution between December 1997 and August 2000, we identified eight patients--four men and four women who were 42-85 years old (mean age, 67 years)--who had tumors adjacent to the gallbladder. All ablations were performed with curative intent. We reviewed the patients' preablation imaging, radiofrequency ablation parameters, and course after ablation. Follow-up ranged from 3 to 22 months (mean, 8 months).

RESULTS

Six patients with colorectal carcinoma and two with hepatocellular carcinoma had a total of 14 tumors adjacent to the gallbladder. Of the 14 tumors, nine (64%) were metastases and five (36%) were hepatocellular carcinoma. Eleven tumors (79%) were located directly adjacent to the gallbladder and three (21%) were located within 1 cm of the gallbladder. Tumor size ranged from 0.9 to 4.5 cm (mean, 3.6 cm). The number of radiofrequency ablations performed on each tumor ranged between one and six (mean, three ablations). Right upper quadrant pain developed in the immediate postablation period (within 7 days after the ablation) in six patients (75%) and ranged in duration from 5 to 21 days (mean, 7 days). Fever developed in four patients (50%), with a mean duration of 5 days. Arthralgia and right shoulder pain developed in one patient (12%). No deaths were noted in the immediate period after ablation. Complete ablation of all tumors visible on CT was achieved in seven patients. Of these, one patient (14%) had local tumor recurrence after 11 months.

CONCLUSION

Radiofrequency ablation of tumors adjacent to the gallbladder is feasible and appears to be safe. Self-limited morbidity after ablation is noted in most patients and is probably related to a mild iatrogenic cholecystitis.