Xuan V. Nguyen

An Exponential Growth in Incidence of Thyroid Cancer: Trends and Impact of CT Imaging

BACKGROUND AND PURPOSE: Workup of incidental thyroid nodules detected on CT imaging could be contributing to the increased diagnosis of small thyroid cancers. The purpose of this study was to evaluate recent trends in the incidence of thyroid cancer, and to determine the relationship between annual CT imaging volume and rate of thyroid cancer diagnosis. MATERIALS AND METHODS: This retrospective cohort study used data bases for thyroid cancer and CT imaging volume. Thyroid cancer data from 1983–2009 were obtained from the Surveillance, Epidemiology, and End Results data base. National Council of Radiation Protection and Measurements Report No. 160 provided data on hospital and nonhospital CT imaging volume for 1993–2006. Trends in thyroid cancer were modeled for overall incidence on the basis of patient age, tumor histologic features, and tumor size and stage. Linear regression analysis was performed to evaluate the strength of the relationship between annual CT scan volume and the incidence of thyroid cancer by tumor size and histologic type. RESULTS: In 2009, the incidence of thyroid cancer was 14 per 100,000, which represented a 1.9-fold increase compared with 2000. The growth in incidence was exponential compared with a minimal linear increase in thyroid cancer mortality rate. The subgroup with the greatest change was subcentimeter papillary carcinoma, with doubling in incidence approximately every 6.2 years. The linear relationship between annual CT scan volume and the incidence of subcentimeter papillary carcinoma was very strong (R2 = 0.98; P < .0001). CONCLUSIONS: The incidence of subcentimeter papillary carcinoma is growing at an exponential rate without significant change in mortality rate. The strong linear relationship between new cases of subcentimeter papillary carcinomas and the number of CT scans per year suggests that an increase in CT scans may increase the detection of incidental thyroid cancers.

Overdiagnosis of thyroid cancer: answers to five key questions.

Thyroid cancer fulfills the criteria for overdiagnosis by having a reservoir of indolent cancers and practice patterns leading to the diagnosis of incidental cancers from the reservoir. The occurrence of overdiagnosis is also supported by population-based data showing an alarming rise in thyroid cancer incidence without change in mortality. Because one of the activities leading to overdiagnosis is the workup of incidental thyroid nodules detected on imaging, it is critical that radiologists understand the issue of overdiagnosis and their role in the problem and solution. This article addresses 1) essential thyroid cancer facts, 2) the evidence supporting overdiagnosis, 3) the role of radiology in overdiagnosis, 4) harms of overdiagnosis, and 5) steps radiologists can take to minimize the problem.

Imaging Thyroid Disease Updates, Imaging Approach, and Management Pearls

There are many disorders that can occur in the thyroid gland, ranging from benign to malignant entities. This article focuses on 5 common problems of the thyroid that require special consideration with regard to optimizing imaging strategies in a multidisciplinary and collaborative platform. These problems are the incidental thyroid nodule, preoperative evaluation of goiter, hyperthyroidism, invasive thyroid cancer, and recurrent thyroid cancer. For each problem essential facts, interesting updates, imaging approach, and management pearls are reviewed.

What to do with incidental thyroid nodules identified on imaging studies? Review of current evidence and recommendations.

Purpose of review To discuss the problem of incidental thyroid nodules (ITN) detected on imaging; summarize the literature for workup methods; and provide recommendations based on current evidence. Recent findings ITN are a common problem, seen in 40–50% of ultrasound and 16% of computed tomography (CT) and MRI studies that include the thyroid. The personal and financial costs of workup frequently outweigh the benefits when considering that the majority of ITN are benign; 25–41% of patients undergo surgery after biopsy, of which more than half ultimately result in a benign diagnosis, and small thyroid cancers have an indolent course. Workup should consider reduction in unnecessary workup in addition to cancer diagnosis. The Society of Radiologists in Ultrasound recommendations have been proposed for ITN detected on ultrasound and found to reduce workup by 30%. For ITN detected on CT, MRI, or PET/CT, a three-tiered system categorization method reduces workup of ITN by 35–46%. Summary The ideal approach to selecting ITN detected on imaging for workup would not be to diagnose all cancers, but to diagnose cancers that have reached clinical significance, while avoiding unnecessary tests and surgery in patients with benign nodules, especially those who have limited life expectancy. The three-tiered system and the Society of Radiologists in Ultrasound recommendations are supported by existing studies and focus on reducing unnecessary biopsy.

Understanding the Risks and Harms of Management of Incidental Thyroid Nodules: A Review

Importance Incidental thyroid nodules are defined as nodules originally detected in a patient with no thyroid-related clinical symptoms, examination findings, or suspected thyroid disease. Medical imaging for diseases in the neck, chest, and spine is a common source of incidental thyroid nodules. They are easily detected but poorly characterized. The next step is to decide whether the incidental thyroid nodule should be further evaluated with ultrasonography. Observations Indiscriminate workup of incidental thyroid nodules with ultrasonography is not cost-effective and is potentially harmful. Although the concern for malignant neoplasms drives workup, the risk for poor outcomes without evaluation is minimal. The rate of malignant tumors in patients with 1 or more thyroid nodules larger than 5 mm is only 1.6%, and most small thyroid cancers are indolent. Substantial evidence suggests that a reservoir of thyroid cancers does not progress, and workup after detection with imaging leads to epidemiologic overdiagnosis. Finally, a significant proportion of patients with benign nodules have cytologic results that are not definitive and require lobectomy. Evidence-based recommendations for incidental thyroid nodules detected at computed tomography, magnetic resonance imaging, nuclear medicine studies, and extrathyroidal ultrasonography include selection criteria for nodule workup based on suspicious imaging findings, patient age, and nodule size. In the absence of clinical risk factors or suspicious imaging findings, workup with dedicated thyroid ultrasonography is only recommended for nodules at least 1.5 cm in patients 35 years or older and for nodules at least 1.0 cm in patients younger than 35 years. Conclusions and Relevance Only a few select incidental thyroid nodules require further evaluation with ultrasonography based on recommendations that aim to diagnose clinically significant thyroid cancers while reducing unnecessary workup and provide guidance for clinical practice.

Effects of Interpersonal Skills Training on MRI Operations in a Saturated Market: A Randomized Trial

PURPOSE The aim of this study was to assess the effects of team training on operational efficiency during outpatient MRI. METHODS In this institutional review board-approved, HIPAA-compliant study, six MRI outpatient sites of a midwestern hospital system were randomized to serve as controls or have their teams trained in advanced communication skills. The fourth quarter of fiscal year 2015 was the trial baseline. The trial ended in the third quarter (Q3) of fiscal year 2016 (FY16). Equipment utilization (completed scans/available slots), hourly scan rates (total orders completed per machine per hour of operation), and no-show rates stratified by time were analyzed using the Cochran-Mantel-Haenszel method, with individual comparisons performed with Bonferroni correction. RESULTS The study encompassed 27,425 MRI examinations. Overall volume peaked at baseline and then declined over the following quarters. Compared with baseline, untrained sites experienced significant drops in equipment utilization (P < .01 for the first quarter of FY16 and P < .0001 for the second quarter of FY16 and Q3 FY16), decreasing from 77% to 65% over the study period, corresponding to a decrease from 1.15 to 0.97 in hourly scan rates. For trained sites, these metrics showed no significant change, with maintenance of hourly scan rates of 1.23 and 1.27 and equipment utilization rates of 83% and 85% between baseline and Q3 FY16. No-show rates remained stable at trained sites but increased at untrained sites in the last two quarters (P < .05). Nationally benchmarked patient satisfaction percentile ranking gradually increased at trained sites from 56th at baseline to 70th and successively decreased at untrained sites from 66th to 44th. CONCLUSIONS MRI outpatient facilities trained in advanced communication techniques may have more favorable operational efficiency than untrained sites in a saturated market.

Economics of MRI Operations After Implementation of Interpersonal Skills Training

PURPOSE Examine the cost of MRI operations before and after implementation of interpersonal skills training to reduce unanticipated patient-related events in an academic medical center. METHODS Teams at four MRI sites (two hospital-based, two freestanding) were trained in evidence-based communication skills in February to April 2015. Training was designed to enable staff members to help patients mobilize their innate coping skills in response to any distress they experienced during their MRI visit. Data were collected before training and afterward from January to June 2016. Staff reported the incidence of disruptive motion, sedation use, MRI delays, incomplete examinations, and no-shows. Cost and revenue associated with MRI operations and staff and physician costs were estimated using Medicare and private insurance rates and data from the US Bureau of Labor Statistics. RESULTS The study included 12,930 outpatient MRI visits. From baseline to follow-up, average monthly patient volume increased from 1,105 to 1,463 at hospital MRI sites and from 245 to 313 at freestanding MRI sites. Patient factors necessitating sedation or interfering with image progression or quality decreased from 9.0% to 5.5% at hospital sites and from 3.1% to 1.2% at freestanding sites. These changes translated into a reduction in operational costs of

Extrapulmonary Findings and Malignancies in Participants Screened With Chest CT in the National Lung Screening Trial

4,600 per 1,000 scheduled patients and an increase in profit of

Emerging Trends in Emergent Stroke Neuroimaging

8,370 per 1,000 scheduled patients in hospital MRI sites, and a corresponding increase in operational costs of

Effects of Patients’ Affect on Adverse Procedural Events during Image-Guided Interventions

1,570 per 1,000 scheduled-patients and an increase in profit of