Gerald D. Dodd

Medical Student Radiology Education: Summary and Recommendations From a National Survey of Medical School and Radiology Department Leadership

The ACR Task Force on Medical Student Education in Radiology, in partnership with the Alliance of Medical Student Educators in Radiology, investigated the current status of how and to what extent medical imaging was being taught in medical schools. The task force executed a 3-part survey of medical school deans, radiology department chairs, and intern physicians. The results provided an updated understanding of the status of radiology education in medical schools in the United States. This summary includes recommendations about how individual radiology departments and ACR members can assist in advancing the specialty of diagnostic radiology through medical student education.

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

PURPOSEnTo 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.nnnMATERIALS AND METHODSnThis 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.nnnRESULTSnThe 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).nnnCONCLUSIONnTriple 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.

Combination Radiofrequency Ablation and Intravenous Radiolabeled Liposomal Doxorubicin: Imaging and Quantification of Increased Drug Delivery to Tumors

PURPOSEnTo 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.nnnMATERIALS AND METHODSnThis 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.nnnRESULTSnAt 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.nnnCONCLUSIONnStudy results show that increased delivery of intravenous liposomal doxorubicin to tumors combined with RF ablation can be depicted and quantified with noninvasive imaging.

The Radiology Resident iPad Toolbox: An Educational and Clinical Tool for Radiology Residents

Tablet computing and mobile resources are the hot topics in technology today, with that interest spilling into the medical field. To improve resident education, a fully configured iPad, referred to as the Radiology Resident iPad Toolbox, was created and implemented at the University of Colorado. The goal was to create a portable device with comprehensive educational, clinical, and communication tools that would contain all necessary resources for an entire 4-year radiology residency. The device was distributed to a total of 34 radiology residents (8 first-year residents, 8 second-year residents, 9 third-year residents, and 9 fourth-year residents). This article describes the process used to develop and deploy the device, provides a distillation of useful applications and resources decided upon after extensive evaluation, and assesses the impact this device had on resident education. The Radiology Resident iPad Toolbox is a cost-effective, portable, educational instrument that has increased studying efficiency; improved access to study materials such as books, radiology cases, lectures, and web-based resources; and increased interactivity in educational conferences and lectures through the use of audience-response software, with questions geared toward the new ABR board format. This preconfigured tablet fully embraces the technology shift into mobile computing and represents a paradigm shift in educational strategy.

High-fidelity Computer Models for Prospective Treatment Planning of Radiofrequency Ablation with In Vitro Experimental Correlation

PURPOSEnTo 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.nnnMATERIALS AND METHODSnGeometric 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.nnnRESULTSnFor 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.nnnCONCLUSIONSnAs 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.

The general radiologist in the 21st century.

An ACR task force investigated the changing roles of general and subspecialized radiologists in current academic and private practice settings. The task force considered historical factors that influenced the evolution of current practice models and evaluated recent socioeconomic trends that will influence the future of radiology practices. The task force proposes a new model of multispecialty radiologists as an exciting and viable option to help build robust future academic and private radiology practices.

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.

In vitro blood-perfused bovine liver model: a physiologic model for evaluation of the performance of radiofrequency ablation devices.

PURPOSEnTo describe an in vitro blood-perfused bovine liver model for the testing of radiofrequency (RF) ablation devices and compare the performance of a specific RF ablation device in the model relative to three other biologic models.nnnMATERIALS AND METHODSnFresh bovine livers were used to create three in vitro models: blood-perfused, Krebs-Henseleit (KH) solution-perfused, and nonperfused. The perfused models were connected to a heart-lung machine via the portal vein and perfused with heparinized autologous blood or KH solution under physiologic conditions. Six swine were used as in vivo liver models. A cluster electrode and RF ablation system was operated in impedance mode for 12 minutes in all models. Ablated livers were sectioned, with long- and short-axis measurements of the ablations obtained, and statistical analysis was performed.nnnRESULTSnA total of 39, 23, 17, and 12 ablations were performed in 14, 6, 5, and 6 blood-perfused bovine livers, KH solution-perfused bovine livers, nonperfused bovine livers, and in vivo porcine livers, respectively. On cut specimens, the average diameters of ablation zones were 4.00 cm (95% CI, 3.88-4.13) in blood-perfused livers, 4.34 cm (95% CI, 4.14-4.50) in KH solution-perfused livers, 4.67 cm (95% CI, 4.50-4.83) in nonperfused livers, and 3.56 cm (95% CI, 3.26-3.83) in in vivo porcine livers. In all models, the ablation zone diameters were normally distributed.nnnCONCLUSIONSnIn the in vitro blood-perfused bovine liver model, the size of ablations produced by an RF ablation device are closer in size to those seen in porcine liver in vivo compared with the lesions produced in KH solution-perfused or nonperfused bovine liver.

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.

3T magnetic resonance imaging accurately depicts radiofrequency ablation zones in a blood-perfused bovine liver model.

PURPOSEnTo determine if noncontrast T1-weighted (T1W) images from 3T magnetic resonance (MR) imaging accurately depict radiofrequency (RF) ablation zones as determined macroscopically and microscopically in a blood-perfused bovine liver model.nnnMATERIALS AND METHODSnThree-dimensional (3D) gradient-recalled echo (GRE) T1W images were obtained on a 3T MR imaging scanner after RF ablations (n = 14) of in vitro blood-perfused bovine livers. The resulting central hypointense and peripheral hyperintense signal regions were measured and compared with the inner tan and outer red zones of the gross specimen. Corresponding ablated hepatic tissue samples were examined microscopically and stained with nicotinamide adenine dinucleotide phosphate (NADPH) to assess for the presence or absence of NADPH diaphorase activity. Bootstrap two-sample hypothesis tests were used to compare MR imaging, gross, and histopathologic measurements.nnnRESULTSnThe MR imaging inner ablation zone had a mean radius of 0.80 cm (range 0.33-1.14 cm); the inner zone plus the outer ablation zone had a mean radius of 1.40 cm (range 1.01-1.74 cm). Comparison of the measurements of the inner ablation zone on MR imaging versus the gross specimen showed equivalence (95% confidence interval [CI] -0.122 cm, 0.223 cm). Comparison of the measurements of the outer ablation zone on MR imaging versus the gross and histologic specimens also showed equivalence (95% CI -0.095 cm, 0.244 cm, and -0.146 cm, 0.142 cm).nnnCONCLUSIONSnNoncontrast 3D GRE T1W 3T MR imaging accurately depicts the RF ablation zones in a blood-perfused bovine liver model and can be used as a noninvasive means to assess the 3D morphologic characteristics of RF ablation lesions in the model.