Locoregional Therapies for Primary and Metastatic Breast Cancer: AJR Expert Panel Narrative Review.

Minimally invasive locoregional therapies have a growing role in the multidisciplinary treatment of primary and metastatic breast cancer. Factors contributing to the expanding role of ablation for primary breast cancer include earlier diagnosis, when tumors are small, and increased longevity of patients whose condition precludes surgery. Cryoablation has emerged as the leading ablative modality for primary breast cancer owing to its wide availability, the lack of need for sedation, and the ability to monitor the ablation zone. Emerging evidence suggests that in patients with oligometastatic breast cancer, use of locoregional therapies to eradicate all disease sites may confer a survival advantage. Evidence also suggests that transarterial therapies-including chemoembolization, chemoperfusion, and radioembolization-may be helpful to some patients with advanced liver metastases from breast cancer, such as those with hepatic oligoprogression or those who cannot tolerate systemic therapy. However, the optimal modalities for treatment of oligometastatic and advanced metastatic disease remain unknown. Finally, locoregional therapies may produce tumor antigens that in combination with immunotherapy drive anti-tumor immunity. Although key trials are ongoing, additional prospective studies are needed to establish the inclusion of interventional oncology in societal breast cancer guidelines to support further clinical adoption and improved patient outcomes.

Prospective Evaluation of Immune Activation Associated with Response to Radioembolization Assessed with PET/CT in Women with Breast Cancer Liver Metastasis.

Background The impact of transarterial radioembolization (TARE) of breast cancer liver metastasis (BCLM) on antitumor immunity is unknown, which hinders the optimal selection of candidates for TARE. Purpose To determine whether response to TARE at PET/CT in participants with BCLM is associated with specific immune markers (cytokines and immune cell populations). Materials and Methods This prospective pilot study enrolled 23 women with BCLM who planned to undergo TARE (June 2018 to February 2020). Peripheral blood and liver tumor biopsies were collected at baseline and 1-2 months after TARE. Monocyte, myeloid-derived suppressor cell (MDSC), interleukin (IL), and tumor-infiltrating lymphocyte (TIL) levels were assessed with use of gene expression studies and flow cytometry, and immune checkpoint and cell surface marker levels with immunohistochemistry. Modified PET Response Criteria in Solid Tumors was used to determine complete response (CR) in treated tissue. After log-transformation, immune marker levels before and after TARE were compared using paired t tests. Association with CR was assessed with Wilcoxon rank-sum or unpaired t tests. Results Twenty women were included. After TARE, peripheral IL-6 (geometric mean, 1.0 vs 1.6 pg/mL; P = .02), IL-10 (0.2 vs 0.4 pg/mL; P = .001), and IL-15 (1.9 vs 2.4 pg/mL; P = .01) increased. In biopsy tissue, lymphocyte activation gene 3-positive CD4+ TILs (15% vs 31%; P < .001) increased. Eight of 20 participants (40% [exact 95% CI: 19, 64]) achieved CR. Participants with CR had lower baseline peripheral monocytes (10% vs 29%; P < .001) and MDSCs (1% vs 5%; P < .001) and higher programmed cell death protein (PD) 1-positive CD4+ TILs (59% vs 26%; P = .006) at flow cytometry and higher PD-1+ staining in tumor (2% vs 1%; P = .046). Conclusion Complete response to transarterial radioembolization was associated with lower baseline cytokine, monocyte, and myeloid-derived suppressor cell levels and higher programmed cell death protein 1-positive tumor-infiltrating lymphocyte levels. © RSNA, 2022 Online supplemental material is available for this article.

Predictors of Major Hemorrhage After Spleen Core Biopsy in Cancer Patients.

In this retrospective study, 232 spleen biopsies from 218 patients with cancer were assessed. Biopsies resulting in hemorrhage requiring hospitalization, transfusion, or other interventions were compared with those that did not. The maximization of the Youden index helped determine the optimal systolic blood pressure (SBP) and platelet count thresholds. There were 15 (7%) major hemorrhages among 211 core biopsies. A multivariate logistic regression model showed that higher SBP, lower platelet count, and the lack of ultrasound guidance were independently associated with major hemorrhage (P < .05). The optimal SBP cutoff was 140 mm Hg, and the platelet count cutoff was 120,000 platelets/µL. In conclusion, the high major hemorrhage rate of 7% among percutaneous core spleen biopsies in patients with cancer may be mitigated by controlling SBP to <140 mm Hg and avoiding biopsy in patients with thrombocytopenia.

Internet Search Trends Relevant to Interventional Oncology: A Google Trends Study (2004-2020).

Interventional Radiology (IR) procedures addressing cancer have been grouped in the subspecialty of interventional oncology and represent an important component of modern multidisciplinary cancer care. This study pinpoints temporal and geographical trends of public online searches for terms related to the field, as well as IR-related cancer therapies. Google Trends data were analyzed for long-term (2004-2020) trends in the United States and worldwide. Overall, search interest for IR increased throughout the United States but decreased globally. Specific search volumes for cancer-related IR techniques such as radioembolization and chemoembolization therapies increased by 2.8- and 2.5-fold, respectively, in the United States, whereas the search volumes for ablation techniques remained steady or decreased. Future research and advocacy may focus on increasing public awareness of the field.

Predictors of Progression-Free Survival and Local Tumor Control after Percutaneous Thermal Ablation of Oligometastatic Breast Cancer: Retrospective Study.

PURPOSE: To describe ablation of bone, liver, lung, and soft tissue tumors from oligometastatic breast cancer and to define predictors of local progression and progression-free survival (PFS). MATERIALS AND METHODS: A total of 33 women (mean age 52 ± 12 years old; range, 28-69 years), underwent 46 thermal ablations of liver (n = 35), lung (n = 7), and bone/soft tissue (n = 4) metastases. Mean tumor diameter was 18 ± 15 mm (range, 6-50 mm). Ablations were performed to eradicate all evident sites of disease (n = 24) or to control growing sites in the setting of other stable or responding sites of disease (n = 22). Patient characteristics, ablation margins, imaging responses, and cases of PFS were assessed. Follow-up imaging was performed using contrast-enhanced computed tomography (CT), magnetic resonance (MR) imaging, or positron-emission tomography/ CT. RESULTS: Median PFS was 10 months (95% confidence interval [CI], 6.2 -14.5 months), and time to local progression was 11 months (95% CI, 5-16 months). Eight patients (24%) maintained no evidence of disease during a median follow-up period of 39 months. Ablation margin ≥5 mm was associated with no local tumor progression. Longer PFS was noted in estrogen receptor-positive patients (12 vs 4 months; P = .037) and younger patients (12 vs 4 months; P = .039) treated to eradicate all sites of disease (13 vs 5 months; P = .05). Eighteen patients (55%) developed new metastases during study follow-up. CONCLUSIONS: Thermal ablation of oligometastatic pulmonary, hepatic, bone, and soft tissue tumors can eliminate local tumor progression if margins are ≥5 mm. Longer PFS was observed in patients who were estrogen receptor-positive and patients who were younger and in whom all sites of disease were eradicated.

Gender Disparity in Industry Relationships With Academic Interventional Radiology Physicians.

OBJECTIVE. Industry relationships drive technologic innovation in interventional radiology and offer opportunities for professional growth. Women are underrepresented in interventional radiology despite the growing recognition of the importance of diversity. This study characterized gender disparities in financial relationships between industry and academic interventional radiologists. MATERIALS AND METHODS. In this retrospective cross-sectional study, U.S. academic interventional radiology physicians and their academic ranks were identified by searching websites of practices with accredited interventional radiology fellowship programs. Publicly available databases were queried to collect each physician's gender, years since medical school graduation, h-index, academic rank, and industry payments in 2018. Wilcoxon and chi-square tests compared payments between genders. A general linear model assessed the impact of academic rank, years since graduation, gender, and h-index on payments. RESULTS. Of 842 academic interventional radiology physicians, 108 (13%) were women. A total $14,206,599.41 was received by 686 doctors (81%); only $147,975.28 (1%) was received by women. A lower percentage of women (74%) than men (83%) received payments (p = 0.04); median total payments were lower for women ($535) than men ($792) (p = 0.01). Academic rank, h-index, years since graduation, and male gender were independent predictors of higher payments. Industry payments supporting technologic advancement were made exclusively to men. CONCLUSION. Female interventional radiology physicians received fewer and lower industry payments, earning 1% of total payments despite constituting 13% of physicians. Gender independently predicted industry payments, regardless of h-index, academic rank, or years since graduation. Gender disparity in interventional radiology physician-industry relationships warrants further investigation and correction.

Autologous Blood Patch Injection versus Hydrogel Plug in CT-guided Lung Biopsy: A Prospective Randomized Trial.

Purpose To compare the effect of autologous blood patch injection (ABPI) with that of a hydrogel plug on the rate of pneumothorax at CT-guided percutaneous lung biopsy. Materials and Methods In this prospective randomized controlled trial ( https://ClinicalTrials.gov , NCT02224924), a noninferiority design was used for ABPI, with a 10% noninferiority margin when compared with the hydrogel plug, with the primary outcome of pneumothorax rate within 2 hours of biopsy. A type I error rate of 0.05 and 90% power were specified with a target study population of 552 participants (276 in each arm). From October 2014 to February 2017, all potential study participants referred for CT-guided lung biopsy (n = 2052) were assessed for enrollment. Results The data safety monitoring board recommended the trial be closed to accrual after an interim analysis met prespecified criteria for early stopping based on noninferiority. The final study group consisted of 453 participants who were randomly assigned to the ABPI (n = 226) or hydrogel plug (n = 227) arms. Of these, 407 underwent lung biopsy. Pneumothorax rates within 2 hours of biopsy were 21% (42 of 199) and 29% (60 of 208); chest tube rates were 9% (18 of 199) and 13% (27 of 208); and delayed pneumothorax rates within 2 weeks after biopsy were 1.4% (three of 199) and 1.5% (three of 208) in the ABPI and hydrogel plug arms, respectively. Conclusion Autologous blood patch injection is noninferior to a hydrogel plug regarding the rate of pneumothorax after CT-guided percutaneous lung biopsy. © RSNA, 2018 Online supplemental material is available for this article.

Clinical Practice Patterns of Interventional Radiologists by Gender.

OBJECTIVE. Given recent specialty attention to workforce diversity, we aimed to characterize potential gender differences in the practice patterns of interventional radiologists (IRs). MATERIALS AND METHODS. Using Medicare claims data, we identified IRs on the basis of the distribution of their billed clinical work effort and descriptively characterized practice patterns by gender. RESULTS. Women represented 8.2% (241/2936) of all IRs identified nationally. Female representation varied geographically (≤ 2% in nine states, ≥ 20% in three states) and by career stage (9.4% among early-career IRs and 6.4% among late-career IRs; 18.8% among early-career IRs in the Northeast). For both female IRs and male IRs, interventional case mixes were similar across service categories (e.g., venous and hemodialysis access, arterial and venous interventions, biopsies and drainages) and by procedural complexity (e.g., 5.7% vs 4.3% for low-complexity procedures and 59.5% vs 61.3% for high-complexity procedures). Average patient complexity scores were also similar for female (2.7 ± 12 [SD]) and male (2.8 ± 12) IRs. Female IRs spent slightly lower portions of their work effort rendering invasive services (66.5% vs 70.0%, respectively) and noninvasive diagnostic imaging (19.0% vs 22.2%) than male IRs but spent more time in evaluation and management clinical visits (14.5% vs 7.9%). Both female IRs and male IRs rendered a majority of their services to female patients (53.4% vs 53.1%). CONCLUSION. Although women remain underrepresented in interventional radiology, female IRs' interventional case composition, procedural complexity, and patient complexity are similar to those of their male colleagues. Female IRs' higher proportion of evaluation and management clinical visits supports the specialty's increased focus on longitudinal care so that interventional radiology will thrive alongside other clinical specialties.

Association of PI3K Pathway Mutations with Early Positron-Emission Tomography/CT Imaging Response after Radioembolization for Breast Cancer Liver Metastases: Results of a Single-Center Retrospective Pilot Study.

PURPOSE: To describe imaging response and survival after radioembolization for metastatic breast cancer and to delineate genetic predictors of imaging responses and outcomes. MATERIALS AND METHODS: This retrospective study included 31 women (average age, 52 y) with liver metastasis from invasive ductal carcinoma who underwent resin and glass radioembolization (average cumulative dose, 2.0 GBq ± 1.8) between January 2011 and September 2017 after receiving ≥ 3 lines of chemotherapy. Twenty-four underwent genetic profiling with MSK-IMPACT or Sequenom; 26 had positron-emission tomography (PET)/CT imaging before and after treatment. Survival after the first radioembolization and 2-4-month PET/CT imaging response were assessed. Laboratory and imaging features were assessed to determine variables predictive of outcomes. Unpaired Student t tests and Fisher exact tests were used to compare responders and nonresponders categorized by changes in fluorodeoxyglucose avidity. Kaplan-Meier survival analysis was used to determine the impact of predictors on survival after radioembolization. RESULTS: Median survival after radioembolization was 11 months (range, 1-49 mo). Most patients (18 of 26; 69%) had complete or partial response based on changes in fluorodeoxyglucose avidity. Imaging response was associated with longer survival (P = .005). Whereas 100% of patients with PI3K pathway mutations showed an imaging response, only 45% of wild-type patients showed a response (P = .01). Median survival did not differ between PI3K pathway wild-type (10.9 mo) and mutant (undefined) patients (P = .50). CONCLUSIONS: These preliminary data suggest that genomic profiling may predict which patients with metastatic breast cancer benefit most from radioembolization. PI3K pathway mutations are associated with improved imaging response, which is associated with longer survival.

Needlestick Injuries in Interventional Radiology Are Common and Underreported.

Purpose To determine the prevalence of and risk factors for needlesticks in interventional radiology physicians, as well as the attitudes, behaviors, and conditions that promote or interfere with reporting of these injuries. Materials and Methods A total of 3889 interventional radiologists from academic and private practice in the United States were surveyed by emailing all interventional radiologist members of the Society of Interventional Radiology, including attending-level physicians and trainees (April-August 2016). The institutional review board waived the need for consent. Questions inquired about the nature, frequency, and type of needlestick and sharps injuries and whether and to whom these incidents were reported. Stepwise regression was used to determine variables predicting whether injuries were reported. Results In total, 908 (23%) interventional radiologists completed at least a portion of the survey. Eight hundred fourteen (91%) of 895 respondents reported a prior needlestick injury, 583 (35%) of 895 reported at least one injury while treating an HIV-positive patient, and 626 (71%) of 884 reported prior training regarding needlestick injury. There was, on average, one needlestick for every 5 years of practice. Most needlestick or sharps injuries were self inflicted (711 [87%] of 817) and involved a hollow-bore device (464 [56%] of 824). Only 566 (66%) of 850 injuries were reported. The most common reasons for not reporting included perceived lack of utility of reporting (79 [28%] of 282), perceived low risk for injury (56 [20%] of 282), noncontaminated needle (53 [19%] of 282), too-lengthy reporting process (37 [13%] of 282), and associated stigma (23 [8%] of 282). Only 156 (25%) of 624 respondents informed their significant other. Stepwise regression assessing variables affecting the likelihood of reporting showed that male sex (P = .009), low-risk patient (P < .0001), self injury (P = .010), trainee status (P < .0001), and the total number of prior injuries (P = .019) were independent predictors of not reporting. Conclusion Needlestick injuries are ubiquitous among interventional radiologists and are often not reported. © RSNA, 2017 Online supplemental material is available for this article.

Association Between Allergies and Psychiatric Disorders in Patients Undergoing Invasive Procedures.

BACKGROUND: Associations between allergies and psychiatric disorders have been reported in the context of depression and suicide; psychiatric disorders may affect pain perception. OBJECTIVE: To investigate the relationship of allergies with psychiatric disorders and pain perception in the context of invasive procedures, specifically during tunneled hemodialysis catheter placement. METHODS: We identified 89 patients (51 men, 38 women), mean age 66 years (range: 23-96), who underwent tunneled hemodialysis catheter placement (1/2014-2/2015), recording numeric rating scale pain scores, medications, psychiatric history, allergies, and smoking status. RESULTS: Of 89 patients, 47 patients had no allergies, and 42 had ≥1 allergy. Patients with allergies were more likely to have a pre-existing psychiatric disorder compared to those without allergies, odds ratio 2.6 (95% CI: 1.0-6.8). Having allergies did not affect procedural sedation or postprocedural pain scores. Multiple logistic regression with age, sex, smoking, presence of allergies, psychiatric history, inpatient/outpatient status, procedure time, and procedural sedation administration as inputs and postprocedural pain as the outcome showed that the only independent predictor was receiving procedural sedation (P = 0.005). CONCLUSIONS: Findings corroborate anecdotal reports of allergies as a marker for psychiatric history. However, having allergies was not associated with increased pain or need for more sedation. Further studies could prospectively assess whether allergies and psychiatric disorders affect patient/doctor perceptions beyond pain during invasive procedures.

Occlusion of the Internal Iliac Artery Is Associated with Smaller Prostate and Decreased Urinary Tract Symptoms.

PURPOSE: To characterize the relationship of proximal internal iliac artery (IIA) occlusion or embolization on prostate volume (PV) and the presence of lower urinary tract symptoms (LUTS) or benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: The study included 2 parts: Part 1 comprised 99 men ≥ 50 years old who underwent abdominopelvic computed tomography angiography for lower extremity claudication assessed in a retrospective cohort design; Part 2 comprised 18 patients who underwent iatrogenic IIA embolization during endovascular aneurysm repair assessed by a within-subjects approach. Prostate volume and IIA origin diameter were measured; IIA occlusion was noted. Chart review documented body mass index, LUTS, impotence, and buttock claudication. RESULTS: Of 99 men in Part 1, 60 had no IIA occlusion, and 39 had IIA occlusion (17 unilateral, 22 bilateral). Prostate volume differed significantly between groups (no IIA occlusion, 27.3 mL; unilateral IIA occlusion, 20.7 mL; bilateral IIA occlusion, 17.1 mL; P = .001). Men without IIA occlusion had more LUTS (27%) than men with IIA occlusion (10%; P = .04). The number of men with complaints of impotence or buttock claudication was similar in both groups (40% vs 46%; P > .05). Multiple regression showed that age and IIA occlusion were independent predictors of PV (P < 0.05), whereas body mass index was not (P > .05), and that IIA occlusion was the only independent predictor of LUTS/BPH (P < .05). Among the 18 men in Part 2, PV declined by 29% after embolization (P = .00001); 6 men had improvement or resolution of LUTS. CONCLUSION: Proximal IIA occlusion is associated with nearly one-third reduction in PV and decreased findings of LUTS/BPH.

Safety and efficacy of 70-150 µm and 100-300 µm drug-eluting bead transarterial chemoembolization for hepatocellular carcinoma.

PURPOSE: To compare the safety and efficacy of using 70-150 µm drug-eluting beads (DEBs) (LC BeadM1; Biocompatibles UK Ltd, Farnham, Surrey, United Kingdom) in addition to 100-300 µm DEBs with 100-300 µm DEBs alone in transarterial chemoembolization for treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A cohort of patients with HCC who underwent transarterial chemoembolization with two vials of 100-300 µm DEBs (group 1, 55 procedures among 42 patients, 33 men, average Model for End-Stage Liver Disease score 10 ± 0.6, 67% Child-Pugh A, 33% Child-Pugh B) was retrospectively compared with a cohort of patients who underwent transarterial chemoembolization with one vial of 70-150 µm DEBs followed by one vial of 100-300 µm DEBs (group 2, 51 procedures among 42 patients, 29 men, average Model for End-Stage Liver Disease score 9 ± 0.6, 73% Child-Pugh A, 27% Child-Pugh B) in regard to adverse events and response on 1-month follow-up imaging using modified Response Evaluation Criteria In Solid Tumors criteria. RESULTS: There was no difference in 1-month imaging response (P = .3). Patients in group 2 were readmitted more often within 1 month for hepatobiliary adverse events (group 2, 25%; group 1, 9%; P < .0001), including ascites, gastrointestinal hemorrhage, biliary dilatation, and cholecystitis. CONCLUSIONS: Despite similar efficacy based on short-term follow-up imaging, transarterial chemoembolization with smaller DEBs (70-150 µm) followed by larger DEBs (100-300 µm) may cause more hepatobiliary adverse events.

Pelvic congestion syndrome: etiology of pain, diagnosis, and clinical management.

Pelvic congestion syndrome is associated with pelvic varicosities that result in chronic pelvic pain, especially in the setting of prolonged standing, coitus, menstruation, and pregnancy. Although the underlying pathophysiology of pelvic congestion syndrome is unclear, it probably results from a combination of dysfunctional venous valves, retrograde blood flow, venous hypertension, and dilatation. Asymptomatic women may also have pelvic varicosities, making pelvic congestion syndrome difficult to diagnose. This article explores the etiologies of pain, use of imaging techniques, and clinical management of pelvic congestion syndrome. Possible explanations for the spectrum of pain among women with pelvic varicosities are also discussed.

High lung shunt fraction in colorectal liver tumors is associated with distant metastasis and decreased survival.

PURPOSE: To assess how intratumoral shunting relates to liver metastasis and to clinical outcome. MATERIALS AND METHODS: Lung shunt fraction (LSF) was calculated from macroaggregated albumin scan after transcatheter injection of radioactive particles in 62 patients with colorectal cancer and liver metastases evaluated for selective internal radiation therapy (SIRT) from May 2007 to August 2012. Assessment was performed of how LSF, liver tumor burden, and systemic chemotherapy relate to survival and the presence of lung metastases. LSF and tumor burden were also assessed in a subset of patients who underwent genetic profiling with SNaPshot analysis. RESULTS: Patients with higher LSF were more likely to have lung metastases and decreased survival, whereas tumor burden was not associated with these outcomes. Patients with genetic mutations had significantly higher LSF than patients with no mutations. Patients who received chemotherapy before SIRT and had low LSF had the longest survival after SIRT. CONCLUSIONS: LSF may be a more robust marker of metastasis than tumor size. Increased LSF secondary to vascular shunting within liver metastasis is an indicator of distant lesions and is associated with decreased survival after SIRT. Intratumoral shunting may provide a conduit for circulating tumor cells to access more remote organs, bypassing filtration by liver parenchyma, and may be an important factor in metastasis from colorectal cancer.

Reduction in portal venous pressure by transjugular intrahepatic portosystemic shunt for treatment of hemorrhagic stomal varices.

OBJECTIVE: Stomal varices can cause life-threatening gastrointestinal hemorrhage in patients with portal hypertension. Optimal therapy is not well defined. The purpose of this study was to determine the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) creation for the treatment of hemorrhagic stomal varices. MATERIALS AND METHODS: All patients who underwent TIPS creation for hemorrhagic stomal varices refractory to medical or endoscopic therapy over a 20-year period (1992-2012) were included. Ten patients (mean age, 63 ± 12 years) were identified. Retrospective chart review was used to document demographic characteristics, procedure details, technical and clinical success, complications, recurrent hemorrhage, and need for repeat interventions. Patients underwent follow-up for an average of 2 years (range, 22 days-9.6 years). RESULTS: All patients had cirrhosis and portal hypertension. Average corrected sinusoidal pressures were 11 ± 2.4 mm Hg (range, 6-15 mm Hg) before TIPS placement and 4.3 ± 1.8 mm Hg (range, 2-8 mm Hg) after TIPS placement. Five patients (50%) underwent adjunctive embolization of stomal varices through the TIPS, which did not affect outcome. Complications included one patient each with a contrast allergy and renal failure. Six patients experienced complete resolution of bleeding without further intervention (60%). Four patients had recurrent stomal hemorrhage. Two of the four needed TIPS revision for occlusion; one underwent oversewing of the ostomy; and in one the hemorrhage resolved with conservative measures after confirmation of TIPS patency. CONCLUSION: TIPS creation, with or without adjunctive variceal embolization, is a safe and effective treatment of refractory hemorrhagic stomal varices. Reintervention for recurrent bleeding may be required and appears effective.

Tissue Ablation: Applications and Perspectives.

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Circulating tumor cells: personalized medicine in interventional oncology?

Innovative technologic advancements have expanded the ability of interventional radiologists to capture and visualize directly tumor cells that have intravasated into the circulation. The detection of these circulating tumor cells (CTCs) is revolutionizing the understanding of the pathogenesis of metastasis and is paving the way for exquisitely sensitive techniques to detect malignancy, monitor recurrence, and prognosticate outcomes. In this review, the prevailing theories on the pathobiology of metastasis and the tools that have been developed to investigate CTCs are summarized. The tremendous impact CTCs are likely to have in oncology is discussed, with particular emphasis on their relevance to interventional oncology.

Reliability of cerebral blood volume maps as a substitute for diffusion-weighted imaging in acute ischemic stroke.

PURPOSE: To assess the reliability of cerebral blood volume (CBV) maps as a substitute for diffusion-weighted MRI (DWI) in acute ischemic stroke. In acute stroke, DWI is often used to identify irreversibly injured "core" tissue. Some propose using perfusion imaging, specifically CBV maps, in place of DWI. We examined whether CBV maps can reliably subsitute for DWI, and assessed the effect of scan duration on calculated CBV. MATERIALS AND METHODS: We retrospectively identified 58 patients who underwent DWI and MR perfusion imaging within 12 h of stroke onset. CBV in each DWI lesion's center was divided by CBV in the normal-appearing contralateral hemisphere to yield relative regional CBV (rrCBV). The proportion of lesions with decreased rrCBV was calculated. After using the full scan duration (110 s after contrast injection), rrCBV was recalculated using simulated shorter scans. The effect of scan duration on rrCBV was tested with linear regression. RESULTS: Using the full scan duration (110 s), rrCBV was increased in most DWI lesions (62%; 95% confidence interval, 48-74%). rrCBV increased with increasing scan duration (P < 0.001). Even with the shortest duration (39.5 s) rrCBV was increased in 33% of lesions. CONCLUSION: Because DWI lesions may have elevated or decreased CBV, CBV maps cannot reliably substitute for DWI in identifying the infarct core.