Feasibility and safety of bipolar radiofrequency track cautery during percutaneous image-guided abdominal biopsy procedures.

PURPOSE: The purpose of this study was to assess the feasibility and safety of using a bipolar radiofrequency track cautery device during percutaneous image-guided abdominal biopsy procedures in at-risk patients. METHODS: Forty-two patients (26-79 years old; female 44%) with at least one bleeding risk factor who underwent an abdominal image-guided (CT or US) biopsy and intended bipolar radiofrequency track cautery (BRTC) were retrospectively studied. An 18G radiofrequency electrode was inserted through a 17G biopsy introducer needle immediately following coaxial 18G core biopsy, to cauterize the biopsy track using temperature control. Bleeding risk factors, technical success, and adverse events were recorded. RESULTS: BRTC was technically successful in 41/42 (98%) of procedures; in one patient, the introducer needle retracted from the liver due to respiratory motion prior to BRTC. BRTC following percutaneous biopsy was applied during 41 abdominal biopsy procedures (renal mass = 12, renal parenchyma = 10, liver mass = 9, liver parenchyma = 5, splenic mass or parenchyma = 4, gastrohepatic mass = 1). All patients had one or more of the following risk factors: high-risk organ (spleen or renal parenchyma), hypervascular mass, elevated prothrombin time, renal insufficiency, thrombocytopenia, recent anticoagulation or anticoagulation not withheld for recommended interval, cirrhosis, intraprocedural hypertension, brisk back bleeding observed from the introducer needle, or subcapsular tumor location. No severe adverse events (grade 3 or higher) occurred. Two (2/41, 5%) mild (grade 1) bleeding events did not cause symptoms or require intervention. CONCLUSION: Bipolar radiofrequency track cautery was feasible and safe during percutaneous image-guided abdominal biopsy procedures. IRB approval: MBG 2022P002277.

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance.

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Smooth Muscle Tumors of the Uterus at MRI: Focus on Leiomyomas and FIGO Classification.

Leiomyomas are smooth muscle tumors of the uterus and are the most common uterine neoplasm. Although leiomyomas are usually asymptomatic, they can manifest with symptoms such as pain or uterine bleeding. Leiomyomas are classified on the basis of their anatomic location and morphology. Localization of leiomyomas relative to the endometrium, myometrium, and uterine serosa with use of the International Federation of Gynecology and Obstetrics (FIGO) classification system is helpful for guiding management in symptomatic patients. The FIGO system is a practical and universally accepted approach for classifying leiomyomas to guide radiologists and clinicians in deciding management. The MRI appearance of conventional leiomyomas is related to their tissue contents of smooth muscle and fibrous tissue and is well established. The MRI features of some leiomyoma subtypes and forms of degeneration also have been described. Other smooth muscle tumors of the uterus recognized in the 2020 World Health Organization classification system include intravenous leiomyomatosis, smooth muscle tumors of uncertain malignant potential, and metastasizing leiomyoma. At the far end of the spectrum are leiomyosarcomas, which are frankly malignant and therefore must be managed accordingly. Although MRI features that suggest a diagnosis of leiomyosarcoma have been proposed, these features overlap with those of some leiomyoma subtypes and degeneration. © RSNA, 2023 See the invited commentary by Fennessy and Gargiulo in this issue. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Screening of cancer predisposition syndromes.

Pediatric patients with cancer predisposition syndromes are at increased risk of developing malignancies compared with their age-matched peers, necessitating regular surveillance. Screening protocols differ among syndromes and are composed of a number of elements, imaging being one. Surveillance can be initiated in infants, children and adolescents with a tumor known or suspected of being related to a cancer predisposition syndrome or where genetic testing identifies a germline pathogenic gene variant in an asymptomatic child. Pre-symptomatic detection of malignant neoplasms offers potential to improve treatment options and survival outcomes, but the benefits and risks of screening need to be weighed, particularly with variable penetrance in many cancer predisposition syndromes. In this review we discuss the benefits and risks of surveillance imaging and the importance of integrating imaging and non-imaging screening elements. We explore the principles of surveillance imaging with particular reference to whole-body MRI, considering the strategies to minimize false-negative and manage false-positive whole-body MRI results, the value of standardized nomenclature when reporting risk stratification to better guide patient management, and the need for timely communication of results to allay anxiety. Cancer predisposition syndrome screening is a multimodality, multidisciplinary and longitudinal process, so developing formalized frameworks for surveillance imaging programs should enhance diagnostic performance while improving the patient experience.

ACR Appropriateness Criteria® Staging and Follow-up of Primary Vaginal Cancer.

Primary vaginal cancer is rare, comprising 1% to 2% of gynecologic malignancies and 20% of all malignancies involving the vagina. More frequently, the vagina is involved secondarily by direct invasion from malignancies originating in adjacent organs or by metastases from other pelvic or extrapelvic primary malignancies. Data on the use of imaging in vaginal cancer are sparse. Insights are derived from the study of imaging in cervical cancer and have reasonable generalizability to vaginal cancer due to similar tumor biology. Given the trend toward definitive chemoradiation for both cancers in all but early stage lesions, principles of postchemoradiation tumor response evaluation are largely analogous. Accordingly, many of the recommendations outlined here are informed by principles translated from the literature on cervical cancer. For pretreatment assessment of local tumor burden and in the case of recurrent vaginal cancer, MRI is the preferred imaging modality. PET/CT has demonstrated utility for the detection of nodal metastatic and unexpected distant metastatic disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

PI-RADS Versions 2 and 2.1: Interobserver Agreement and Diagnostic Performance in Peripheral and Transition Zone Lesions Among Six Radiologists.

BACKGROUND. PI-RADS version 2.1 (v2.1) modifications primarily address transition zone (TZ) interpretation. The revisions also impact peripheral zone (PZ) interpretation, which has received less attention. OBJECTIVE. The purpose of this study was to compare interobserver agreement of PI-RADS version 2 (v2) and v2.1 in the prostate PZ and TZ and perform a pilot comparison of their diagnostic performance in the two zones. METHODS. Six radiologists with varying experience retrospectively assessed 80 prostate lesions (40 PZ, 40 TZ) on MRI in separate sessions for PI-RADS v2 and v2.1. Interobserver agreement was assessed using Conger kappa (κ). For 50 lesions with pathology data, average AUC for detecting clinically significant cancer was compared between versions using multireader multicase statistical methods. Error variance and covariance results informed post hoc power analysis. RESULTS. Interobserver agreement for PI-RADS category 4 or greater was higher for version 2.1 (κ = 0.64) than version 2 (κ = 0.51) in the PZ, but similar for version 2 (κ = 0.64) and version 2.1 (κ = 0.60) in the TZ. The PI-RADS v2.1 DWI descriptor "linear/wedge-shaped" had higher agreement than its predecessor version 2 descriptor "indistinct hypointense" (κ = 0.52 vs κ = 0.18) and yielded 14 more true-negative versus five more false-negative interpretations. The ADC signal descriptor "markedly hypointense," for which only version 2.1 provides a specific definition, had lower agreement in version 2.1 (κ = 0.26) than version 2 (κ = 0.52). Modified TZ T2-weighted category 2 descriptors in version 2.1 had fair agreement (κ = 0.21), and agreement for PI-RADS category 2 in the TZ was lower in version 2.1 (κ = 0.31) than version 2 (κ = 0.57). DWI upgraded a TZ lesion category from 2 to 3 in four patients, detecting two additional cancers. Average AUC was not different between versions 2 and 2.1 for the PZ (AUC, 0.81 vs 0.85; p = .24) or the TZ (AUC, 0.69 vs 0.69; p = .94), though among experienced readers AUC was higher for version 2.1 than version 2 for the PZ (0.91 vs 0.82; p = .001). Overall performance comparison had sufficient power (0.8) to detect a 0.085 difference in AUC. CONCLUSION. Interobserver agreement improved using PI-RADS v2.1 in the PZ but not the TZ. Diagnostic performance improved using version 2.1 only in the PZ for experienced readers. Specific version 2.1 modifications yielded mixed results. CLINICAL IMPACT. The impact of PI-RADS v2.1 in the PZ is notable given the emphasis on version 2.1 TZ modifications. The findings suggest areas in which additional modification could further improve interobserver agreement and performance.

Whole-Body MRI Surveillance of Cancer Predisposition Syndromes: Current Best Practice Guidelines for Use, Performance, and Interpretation.

OBJECTIVE. Whole-body MRI is a valuable tool in the surveillance of cancer predisposition syndromes (CPSs). Because it allows wide-FOV imaging without ionizing radiation, whole-body MRI is ideal in pediatric patients, enabling efficient assessment of different organ systems for multifocal disease. This article summarizes the use of whole-body MRI in pediatric patients with CPSs for earlier detection of malignancy, provides evidence where available, and offers guidance where lacking because of the rarity of CPSs. Protocol modifications and technique performance in specific CPSs are also considered. CONCLUSION. Whole-body MRI is the preferred imaging modality for surveillance of pediatric patients with CPSs, and the growing literature supports its importance in presymptomatic cancer detection.

Turning around cancer: Oncology imaging and implications for emergency department radiology workflow.

PURPOSE: Oncologic imaging in the emergency department (ED) is frequently encountered, including non-acute scans known as "metastatic workups" or "staging" (referred to as "cancer staging computed tomography (CT) exams"). This study examines the impact of oncologic staging CT exams on ED imaging turnaround time (TAT), defined as the time from the end of the CT exam to a final signed radiologist report, as well as order to scan completion time. METHODS: A retrospective review was conducted of all adult patients presenting to an urban, quaternary academic medical center ED from February 2016 to September 2017, who had CT imaging ordered, performed, and interpreted in the ED imaging department. CT exams containing institution-specific cancer descriptors were included. After excluding all acute exams, cancer staging CT exams were compared to a matched cohort of non-oncologic ED CT exams to evaluate median TAT and order to scan completion time using a log transformed multivariable linear regression. RESULTS: Adjusting for age and CT body part, cancer staging CT exams were associated with an independently statistically significant increased median log TAT compared to non-oncologic ED CT exams (114.5 min [IQR 112] versus 69 min [IQR 67], respectively, p < .0001) and an independently statistically significant increased median log initial order to scan completion time (166 min [IQR: 89] vs 119 min [IQR: 93], p < .0001). CONCLUSION: Oncology patients receiving non-acute metastatic workup scans in the ED have a significantly longer TAT compared to non-oncologic ED CT exams as well as longer order to scan completion times.

Disparities over Time in Volume, Day of the Week, and Patient Complexity between Paracentesis and Thoracentesis Procedures Performed by Radiologists versus Those Performed by Nonradiologists.

PURPOSE: To compare the disparities between the paracenteses and thoracenteses performed by radiologists with those performed by nonradiologists over time. Variables included the volume of procedures, the days of the week, and the complexity of the patient's condition. MATERIALS AND METHODS: Using carrier claims files for a 5% national sample of Medicare beneficiaries from 2004 to 2016, paracentesis and thoracentesis examinations were retrospectively classified by physician specialty (radiologist vs nonradiologist), day of the week (weekday vs weekend), and the complexity of the patient's condition (using Charlson comorbidity index scores). The Pearson chi-square and independent samples t-test were used for statistical analysis. RESULTS: Between 2004 and 2016, the proportion of all paracentesis and thoracentesis procedures performed by radiologists increased from 70% to 80% and from 47% to 66%, respectively. Although radiologists increasingly performed more of both services on both weekends and weekdays, the share performed by radiologists was lower on weekends. For most of the first 9 years across the study period, radiologists performed paracentesis in patients with more complex conditions than those treated by nonradiologists, but the complexity of patients' conditions was similar during recent years. For thoracentesis, the complexity of patients' conditions was similar for both specialty groups across the study period. CONCLUSIONS: The proportion of paracentesis and thoracentesis procedures performed in Medicare beneficiaries by radiologists continues to increase, with radiologists increasingly performing most of both services on weekends. Nonetheless, radiologists perform disproportionately more on weekdays than on weekends. Presently, radiologists and nonradiologists perform paracentesis and thoracentesis procedures in patients with similarly complex conditions. These interspecialty differences in timing and complexity of the patient's condition differ from those recently described for several diagnostic imaging services, reflecting the unique clinical and referral patterns for invasive versus diagnostic imaging services.

Advanced CT Techniques for Decreasing Radiation Dose, Reducing Sedation Requirements, and Optimizing Image Quality in Children.

CT is an invaluable diagnostic tool for pediatric patients; however, concerns have arisen about the potential risks of ionizing radiation associated with diagnostic imaging in young patients, particularly for pediatric populations that may require serial CT examinations. Recent attention has also been focused on the immediate and long-term risks of administration of anesthetic medications to infants and young children who require sedation to undergo imaging examinations. These concerns can be mitigated with use of advanced CT techniques that can decrease scan time and radiation dose while preserving image quality. In this article, current state-of-the-art CT acquisition techniques are reviewed as part of a comprehensive strategy to reduce radiation dose, decrease sedation needs, and optimize image quality in infants and young children. Three imaging strategies are discussed, including (a) dual-energy CT (DECT), (b) imaging with a low tube potential, and (c) rapid scanning. Consolidating multiphase imaging protocols into a single phase with virtual nonenhanced imaging on DECT scanners, as well as use of low tube voltage, can reduce the radiation dose while increasing the conspicuity of contrast material-enhanced structures with a reduced volume of iodinated contrast material and a reduced rate of injection. Rapid scanning techniques with either ultrahigh pitch at dual-source CT or with wide-area detector single-source CT facilitate scanning without the need for sedation in many children. ©RSNA, 2019 See discussion on this article by Szczykutowicz .

Diagnostic Value of Fine-Needle Aspiration in Male Breast Lesions.

OBJECTIVE: Differentiation between gynecomastia, a common cause of male breast enlargement, and breast cancer is crucial for appropriate management. Fine-needle aspiration biopsy has been shown to be sensitive and specific in assessing female breast lesions, comparable to core needle biopsy. Few such studies have been conducted in men. We assessed its diagnostic value in a male patient cohort. STUDY DESIGN: Men who underwent fine-needle aspiration (FNA) for palpable breast lesions at Massachusetts General Hospital from January 2007 to December 2016 were evaluated. Clinical data, radiographic findings, and cytologic diagnoses of 74 breast FNA from 71 men were reviewed. Breast aspirates were classified as nondiagnostic, benign, atypical, suspicious for malignancy, or malignant. Histology was obtained in 37 cases, and clinical and radiological data were used as follow-up in 37 patients. RESULTS: Most FNA biopsies (73%) were performed by cytopathologists, and 93.2% of the breast FNA in men were adequate; 58% showed benign processes, mostly gynecomastia (n = 22), and 28.4% (n = 21) were malignant, most often ductal carcinoma. No false-positive cytologies were obtained, and there was 1 false-negative cytology. In our study, FNA of palpable male breast lesions was 95.8% sensitive and 100% specific. CONCLUSIONS: FNA allows sensitive, specific, and safe evaluation and diagnosis of palpable male breast lesions.

Comparison of three oral contrast preparations for magnetic resonance enterography in pediatric patients with known or suspected Crohn disease: a prospective randomized trial.

BACKGROUND: Oral contrast preparation is fundamental to ensuring diagnostic examination quality for magnetic resonance enterography (MRE), yet little is known about the relative palatability and tolerability of various oral contrast agents in pediatric patients with known or suspected inflammatory bowel disease. OBJECTIVE: We prospectively compared three MRE oral preparations in pediatric patients with known or suspected Crohn disease with respect to patient-reported tolerability and radiologist-determined small-bowel distension and opacification. MATERIALS AND METHODS: Seventy-five pediatric patients (mean age 14.8 years, 55% female) with known or suspected Crohn disease referred for MRE were randomized to an oral preparation with a sugar alcohol-based flavored beverage (Breeza), polyethylene glycol preparation (MiraLAX), or low-concentration barium sulfate suspension (VoLumen). Patients were instructed to consume oral contrast agent (using a weight-based protocol) beginning 60 min prior to MRE imaging. Following MRE, patients completed a questionnaire regarding their oral preparation solution including: taste (1-5 scale), feeling of well-being (1-5 scale) and willingness to consume again (yes/no). Two radiologists reviewed all MRE exams and rated exams for global features (active disease, overall small-bowel distention [1-4 scale]) and features specific to individual small-bowel segments (extent of distention, maximal luminal diameter, opacification, and susceptibility artifact). Statistical methods included one-way analysis of variance (ANOVA) with Tukey honest difference and Fisher exact tests. RESULTS: The overall rate of completion of the entire prescribed contrast volume was 53% (40/75), with a significantly higher rate of completion for MiraLAX than for VoLumen (70% vs. 30%, P=0.007). Crossover to a different preparation occurred in nine patients (12%) and was significantly more frequent when the initial preparation was VoLumen versus MiraLAX (29% vs. 0%, P=0.005). Mean subjective taste ratings for both MiraLAX (3.4, P<0.0001) and Breeza (2.8, P=0.006) were superior to those of VoLumen (1.9), which persisted in the subset of patients with MRE evidence of active Crohn disease. Patients who consumed MiraLAX were more likely to be willing to drink it again compared to those consuming VoLumen (82% vs. 46%, P=0.009). Overall small-bowel distention and bowel-segment-specific metrics (distention, maximal diameter, opacification and susceptibility) did not significantly differ among groups. CONCLUSION: In pediatric patients with known or suspected Crohn disease, MiraLAX and Breeza were rated as more palatable than VoLumen, and all three preparations achieved a similar degree of small-bowel distension and opacification on MRE. Imaging centers performing MRE should stock multiple oral contrast preparations because a sizable proportion of children require more than one agent to ingest the requisite oral contrast volume.

Current and Emerging Roles of Whole-Body MRI in Evaluation of Pediatric Cancer Patients.

Imaging is fundamental to diagnosis and management of pediatric patients with cancer and cancer predisposition syndromes (CPSs). Whole-body MRI has emerged as a versatile tool for pediatric oncologic imaging, with the potential to spare children from ionizing radiation imparted by conventional modalities such as CT and PET. Whole-body MRI also enables simultaneous high-resolution local-regional staging and wide field-of-view distant staging in the same imaging session, with superior evaluation of the brain, spine, liver, and marrow. Recent technical advances have reduced imaging times and enhanced image quality, with continued advances on the near horizon. Pulse sequences such as whole-body diffusion-weighted imaging have also broadened the range of diagnostic information obtainable. In addition, increasing identification of children with CPSs has compelled efforts to establish surveillance imaging strategies for affected individuals, with whole-body MRI playing a pivotal role in screening algorithms for several CPSs. In light of these emerging trends, a working knowledge of oncologic whole-body MRI applications and evolving CPS surveillance algorithms is vital to providers who participate in the care of pediatric patients affected by or predisposed to cancer. Recognizing both the strengths and limitations of whole-body MRI not only enables more thoughtful implementation but also improves the accuracy of image interpretation. ©RSNA, 2019 See discussion on this article by Khanna .

Feasibility of Perioperative Micro-Computed Tomography of Human Lung Cancer Specimens: A Pilot Study.

CONTEXT.­: Lesion localization during intraoperative frozen section of lung resection specimens can be challenging. Imaging could aid lesion localization while enabling 3-dimensional specimen analysis. OBJECTIVE.­: To assess the feasibility of integrating micro-computed tomography (micro-CT) into the perioperative evaluation of fresh surgical lung resection specimens. DESIGN.­: Fresh lung specimens from patients with a presumptive diagnosis of lung cancer were imaged with micro-CT prior to routine histopathologic and molecular analysis. Micro-CT images were assessed to determine image quality, lesion size, and distance from lesion to the nearest surgical margin. Micro-CT measurements were compared to pathologic measurements using Bland-Altman analysis. RESULTS.­: A total of 22 specimens from 21 patients were analyzed (mean image acquisition time, 13 ± 6 minutes). Histologic quality of imaged specimens was indistinguishable from a control group of nonimaged lung specimens. Artifacts, most commonly from specimen deflation (n = 8), obscured fine detail on micro-CT images of 10 specimens. Micro-CT could successfully localize the target lesion in the other 12 specimens. Distance to the nearest surgical margin was determined in 10 specimens. Agreement of micro-CT with final pathology was good, with a mean difference of -2.8% (limits of agreement -14.5% to 20.0%) for lesion size and -0.5 mm (limits of agreement -4.4 to 3.4 mm) for distance to nearest surgical margin. CONCLUSIONS.­: Micro-CT of fresh surgical lung specimens is feasible and has the potential to evaluate the size and location of lesions within resection specimens, as well as distance to the nearest surgical margin, all without compromising specimen integrity.

Appropriateness of Extremity Magnetic Resonance Imaging Examinations in an Academic Emergency Department Observation Unit.

INTRODUCTION: Emergency departments (ED) and hospitals face increasing challenges related to capacity, throughput, and stewardship of limited resources while maintaining high quality. Appropriate utilization of extremity magnetic resonance imaging (MRI) examinations within the emergency setting is not well known. Therefore, this study aimed to determine indications for and appropriateness of MRI of the extremities for musculoskeletal conditions in the ED observation unit (EDOU). METHODS: We conducted this institutional review board-approved, retrospective study in a large, quaternary care academic center and Level I trauma center. An institutional database was queried retrospectively to identify all adult patients undergoing an extremity MRI while in the EDOU during the two-year study period from October 2013 through September 2015. We compared clinical history with the American College of Radiology (ACR) Appropriateness Criteria® for musculoskeletal indications. The primary outcome was appropriateness of musculoskeletal MRI exams of the extremities; examinations with an ACR Criteria score of seven or higher were deemed appropriate. Secondary measures included MRI utilization and imaging findings. RESULTS: During the study period, 22,713 patients were evaluated in the EDOU. Of those patients, 4,409 had at least one MRI performed, and 88 MRIs met inclusion criteria as musculoskeletal extremity examinations (2% of all patients undergoing an MRI exam in the EDOU during the study period). The most common exams were foot (27, 31%); knee (26, 30%); leg/femur (10, 11%); and shoulder (10, 11%). The most common indications were suspected infection (42, 48%) and acute trauma (23, 26%). Fifty-six percent of exams were performed with intravenous contrast; and 83% (73) of all MRIs were deemed appropriate based on ACR Criteria. The most common reason for inappropriate imaging was lack of performance of radiographs prior to MRI. CONCLUSION: The majority of musculoskeletal extremity MRI examinations performed in the EDOU were appropriate based on ACR Appropriateness Criteria. However, the optimal timing and most-appropriate site for performance of many clinically appropriate musculoskeletal extremity MRIs performed in the EDOU remains unclear. Potential deferral to the outpatient setting may be a preferred population health management strategy.

Day of Week, Site of Service, and Patient Complexity Differences in Venous Ultrasound Interpreted by Radiologists Versus Nonradiologists.

OBJECTIVE: Nationally, nonradiologists interpret an increasing proportion of lower extremity venous duplex ultrasound (LEVDU) examinations. We aimed to study day of week, site of service, and patient complexity differences in LEVDU services interpreted by radiologists versus nonradiologists. MATERIALS AND METHODS: Using carrier claims files for a 5% national sample of Medicare beneficiaries from 2012 to 2015, we retrospectively classified all LEVDU examinations by physician specialty (radiologist versus nonradiologist), day of week (weekday versus weekend), site of service, and patient Charlson Comorbidity Index (CCI) scores. Pearson's χ2 was used to test statistical significance. RESULTS: Of 760,433 LEVDU examinations for which provider specialty could be determined, 439,964 (58%) were interpreted by radiologists and 320,469 (42%) by nonradiologists. On weekends, radiologists interpreted 75% (66,094 of 88,244) and nonradiologists 25% (22,150 of 88,244) (P < .0001). Of LEVDU examinations interpreted by radiologists, 57% were performed in the inpatient or emergency department settings, and 70% of LEVDU examinations interpreted by nonradiologists were performed in the private office or outpatient hospital setting. Radiologists interpreted a slightly larger proportion (17%) of their examinations on patients with more comorbidities (CCI of ≥3) than nonradiologists (15%) (P < .0001). CONCLUSION: Compared with nonradiologists, radiologists interpret a disproportionately larger share of weekend (versus weekday) LEVDU examinations and a considerably larger proportion in higher acuity settings. Additionally, the patients on whom they render services have more comorbidities. To optimize around-the-clock patient access to necessary imaging, emerging quality payment programs should consider the timing and sites of service, as well as patient complexity.

Increasing utilization of emergency department neuroimaging in Medicare beneficiaries from 1994 to 2015.

OBJECTIVE: To assess for changes in emergency department (ED) utilization of neuroimaging in Medicare fee-for-service beneficiaries from 1994 to 2015. METHODS: Using Medicare Physician Supplier Procedure Summary Master Files, annual ED volumes of head computed tomography (CT), magnetic resonance (MR), and carotid duplex ultrasound (CDUS) were assessed from 1994 through 2015. Annual volumes of head CT angiography (CTA), neck CTA, head MR angiography (MRA), and neck MRA studies were assessed from 2001 (first year of unique reporting codes) through 2015. Longitudinal population-based utilization rates were calculated using annual Medicare Part B enrollment, and utilization rates were normalized annually per 1000 ED visits. RESULTS: From 1994 through 2015, ED neuroimaging utilization rates per 1000 ED visits increased 660% overall (compound annual growth rate [CAGR] 9%); 529% for head CT (CAGR 9%); 1451% for head MRI (CAGR 14%); and by 104% for CDUS (CAGR 3%). From 2001 to 2015, rates increased 14,600% (CAGR 43%) and 17,781% (CAGR 45%) for head and neck CTA, respectively, and 525% (CAGR 14%) and 667% (CAGR 16%) for head and neck MRA, respectively. Trends were similar when volumes were normalized for annual Medicare fee-for-service enrollment. Non-contrast head CT was the most common imaging modality throughout the study period (86% of annual neuroimaging volume in 1994; 89% in 2015). CONCLUSIONS: In Medicare beneficiaries, neuroimaging utilization in the ED grew unabated from 1994 through 2015, with growth of head and neck CTA far outpacing other modalities. Non-contrast head CT remains by far the dominant ED neuroimaging examination.