Environmental Factors Predictive of No-Show Visits in Radiology: Observations of Three Million Outpatient Imaging Visits Over 16 Years.

PURPOSE: To evaluate the impact of environmental and socioeconomic factors on outpatient cancellations and "no-show visits" (NSVs) in radiology. MATERIALS AND METHODS: We conducted a retrospective analysis by collecting environmental factor data related to outpatient radiology visits occurring between 2000 and 2015 at our multihospital academic institution. Appointment attendance records were joined with daily weather observations from the National Oceanic and Atmospheric Administration and estimated median income from the US Census American Community Survey. A multivariate logistic regression model was built to examine relationships between NSV rate and median income, commute distance, maximum daily temperature, and daily snowfall. RESULTS: There were 270,574 (8.0%) cancellations and 87,407 (2.6%) NSVs among 3,379,947 scheduled outpatient radiology appointments and 575,206 unique patients from 2000 to 2015. Overall cancellation rates decreased from 14% to 8%, and NSV rates decreased from 6% to 1% as median income increased from $20,000 to $120,000 per year. In a multivariate model, the odds of NSV decreased 10.7% per $10,000 increase in median income (95% confidence interval [CI]: 10.3%-11.1%) and 2.0% per 10°F increase in maximum daily temperature (95% CI: 1.3%-1.6%). The odds of NSV increased 1.4% per 10-mile increase in commute distance (95% CI: 1.3%-1.6%) and 4.5% per 1-inch increase in daily snowfall (95% CI: 3.6%-5.3%). Commute distance was more strongly associated with NSV for those in the two lower tertiles of income than the highest tertile (P < .001). CONCLUSION: Environmental factors are strongly associated with patients' attendance at scheduled outpatient radiology examinations. Modeling of appointment failure risk based on environmental features can help increase the attendance of outpatient radiology appointments.

Understanding Why Patients No-Show: Observations of 2.9 Million Outpatient Imaging Visits Over 16 Years.

PURPOSE: To understand why patients "no-show" for imaging appointments, and to provide new insights for improving resource utilization. MATERIALS AND METHODS: We conducted a retrospective analysis of nearly 2.9 million outpatient examinations in our radiology information system from 2000 to 2015 at our multihospital academic institution. No-show visits were identified by the "reason code" entry "NOSHOW" in our radiology information system. We restricted data to radiography, CT, mammography, MRI, ultrasound, and nuclear medicine examinations that included all studied variables. These variables included modality, patient age, appointment time, day of week, and scheduling lead time. Multivariate logistic regression was used to identify factors associated with no-show visits. RESULTS: Out of 2,893,626 patient visits that met our inclusion criteria, there were 94,096 no-shows during the 16-year period. Rates of no-show visits varied from 3.36% in 2000 to 2.26% in 2015. The effect size for no-shows was strongest for modality and scheduling lead time. Mammography had the highest modality no-show visit rate of 6.99% (odds ratio [OR] 5.38, P < .001) compared with the lowest modality rate of 1.25% in radiography. Scheduling lead time greater than 6 months was associated with more no-show visits than scheduling within 1 week (OR 3.18, P < .001). Patients 60 years and older were less likely to miss imaging appointments than patients under 40 (OR 0.70, P < .001). Mondays and Saturdays had significantly higher rates of no-show than Sundays (OR 1.52 and 1.51, P < .001). CONCLUSION: Modality type and scheduling lead time were the most predictive factors of no-show. This may be used to guide new interventions such as targeted reminders and flexible scheduling.

Predictive modeling to identify scheduled radiology appointments resulting in non-attendance in a hospital setting.

No-show appointments are a troublesome, but frequent, occurrence in radiology hospital departments and private practice. Prior work in medical appointment no-show prediction has focused on general practice and has not considered features specific to the radiology environment. We collect data from 16 years of outpatient examinations in a multi-site hospital radiology department. Data from the radiology information system (RIS) are fused with patient income estimated from U.S. Census data. Features were categorized into three groups: Patient, Exam, and Scheduling. Models based on the total feature set and separately on each feature group were developed using logistic regression to assess the per-appointment likelihood of no-show. After five-fold cross-validation, no-show prediction using the total feature set from 554,611 appointments yielded an area under the curve (AUC) of 0.770 ± 0.003. Feature groups that were most informative in the prediction of no-show appointments were those based on the type of exam and on scheduling attributes such as the lead time of scheduling the appointment. A data-driven no-show prediction model like the one presented here could be useful to schedulers in the implementation of an automated scheduling policy or the assignment of examinations with a high risk of no-show to lower impact appointment slots.

Evaluation of diagnostic performance of 18F-FDG-PET compared to CT in detecting potential causes of fever of unknown origin in an academic centre.

Determining the cause of fever of unknown origin (FUO) often proves challenging to attending physicians and the role of conventional imaging in this setting has been uncertain. In this retrospective study, we examined the role of fluorine-18 fluorodesoxyglucose-positron emission tomography ((18)F-FDG-PET) compared to computed tomography (CT) in diagnosing the potential etiology of FUO. To accomplish this task, we identified patients with FUO who underwent (18)F-FDG-PET for detecting the source of fever. Twenty-four patients (16 males and 8 females, age range = 17-80, mean age = 49.5) were examined with (18)F-FDG-PET of which 18 were also assessed with a diagnostic CT (within 3 weeks, mean interval = 7.5 days). The PET and CT findings were reviewed and the presence of focal (18)F-FDG uptake or gross CT lesions was considered a potential site causing FUO. Of patients who underwent PET alone, ⅚ were reported as positive. Of the 18 who had both PET and diagnostic CT, PET was positive in 18 and CT was positive in only 7 cases. Of positive findings on PET, etiologies included infection (11), non-infectious inflammation (8), lymphoma (3), and other cancers (1). Of positive findings on CT, etiologies included infection (3), lymphoma (1), non-infectious inflammation (2) and other cancers (1). Importantly, we found no cases with positive CT and negative PET findings. In conclusion, accordingly to our findings, (18)F-FDG-PET appears to be of great value in assessing patients with FUO, especially when caused by infection or inflammation. Fluorine-18 FDG-PET is more sensitive than diagnostic CT in detecting and localizing diseased sites, and is the optimal imaging modality to evaluate patients with FUO.

PET and PET/CT in the management of thyroid cancer.

The introduction of PET(-CT) has brought about a major paradigm shift in the management of thyroid carcinoma, especially from the diagnostic standpoint. From the viewpoint of patient management, the areas where it has made significant impact include the following: (1) the detection of disease focus in patients with differentiated thyroid carcinoma with elevated Tg levels and negative radioiodine scan. When localized disease is identified with F-18 FDG-PET-CT, surgery or focused radiotherapy could be utilized to eradicate the tumor; (2) the localization of disease in patients of MTC with elevated serum calcitonin levels; (3) the detection of unsuspected focal F-18 FDG uptake in the thyroid in patients undergoing whole body F-18 FDG PET for a different indication. This would prompt a workup to rule out thyroid carcinoma. The use of I-124 is evolving at this time and has been of great promise with regard to (a) its better efficacy of lesion detection and (b) the ability to provide lesion-specific dosimetry. In addition, F-18 FDG PET appears to be of potential value in patients with thyroid lymphoma in making the initial diagnosis, monitoring therapeutic response, and assessing for residual disease and/or recurrence.

A protective role of Mer receptor tyrosine kinase in nephrotoxic serum-induced nephritis.

The Mer receptor tyrosine kinase is strongly expressed in the glomerulus. We wondered if this molecule might modify immune-mediated glomerular disease through its functions as a receptor for apoptotic cells and immunoregulatory molecule. Mer-knockout (KO) mice showed decreased survival rate and greatly increased proteinuria and serum urea levels compared to wild type (WT) mice by day 3 after injection of NTS. Their glomeruli were hyperplastic and later became necrotic. In the glomerulus of WT mice, a significant increase of Mer expression was observed. Apoptotic bodies were evident in NTS-treated Mer-KO kidneys, but not in normal controls. NTS-treated Mer-KO mice had massive neutrophil infiltration and inflammatory cytokine expression. Mer thus has a critical role in attenuating renal inflammation, both as a receptor for apoptotic cells and as a molecule that downregulates inflammation.

F-18 FDG-PET/CT evaluation of patients with differentiated thyroid cancer with negative I-131 total body scan and high thyroglobulin level.

PURPOSE: The aim was to evaluate the incremental diagnostic rate of F-18 fluoro-fluorodeoxygulose positron emission tomography/computed tomography (F-18 FDG-PET/CT) in patients with negative I-131 whole body scans and high Tg levels. The secondary end points were correlations between F-18 FDG-PET/CT positive results and Tg levels and comparison between F-18 FDG-PET/CT accuracy in patients "on-therapy" with suppressed thyroid stimulating hormone (TSH) and those with high TSH levels. METHODS: We studied 52 patients who had undergone total thyroidectomy and remnant ablation; they had high Tg levels (average = 156 ng/mL; SD +/- 274) after 3 weeks of levothyroxine withdrawal and negative I-131 total body scans after therapeutic doses. RESULTS: We noted a statistically significant positive correlation between F-18 FDG-PET/CT positive results and Tg levels, irrespective of levothyroxine therapy regimen. Tg levels between F-18 FDG-PET/CT positive/negative groups were significantly different and we did not note any statistically significant correlation between F-18 FDG-PET/CT results and TSH levels, tumor size, and combination of Tg/TSH levels. CONCLUSIONS: Our results indicate that F-18 FDG-PET/CT is a useful diagnostic tool in patients with differentiated thyroid carcinoma and with negative I-131 total body scans and high Tg levels. The levothyroxine therapy regimen does not influence F-18 FDG-PET/CT results and the rate of F-18 FDG-PET/CT positive results appears to correlate with the Tg levels. The highest accuracy is reached when the study is performed for patients with Tg levels higher than 21 ng/mL.

A patient with medullary thyroid carcinoma and right ventricular cardiac metastasis treated by (90)Y-Dotatoc.

Medullary thyroid carcinoma (MTC) is rare derived from C cells of the thyroid gland and represents approximately 5% of all thyroid carcinomas. We report a case of a 74 years old male with MTC, diagnosed in 2002 and treated with total thyroidectomy and lymphadenectomy. A metastatic lesion was diagnosed on the right ventricle by indium-111-octreoscan, fluorine-18-fluorodeoxyglucose-positron emission tomography/computerized tomography, echocardiography, magnetic resonance imaging, high resolution computed tomography and was confirmed by histopathology. We present the results of treatment of this patient with yttrium-90-DOTA-tyr(3)-octreotide.

Functional imaging of inflammatory diseases using nuclear medicine techniques.

Molecular imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) is increasingly used to diagnose, characterize, and monitor disease activity in the setting of inflammatory disorders of known and unknown etiology. These disorders include sarcoidosis, atherosclerosis, vasculitis, inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and degenerative joint disease. Gallium-67 ((67)Ga) citrate, labeled leukocytes with technetium-99m ((99m)Tc) or indium-111 ((111)In), and (18)F-fluorodeoxyglucose (FDG) represent the most widely used radiopharmaceutical agents. However, other preparations, such as labeled murine monoclonal antigranulocyte antibodies and labeled human polyclonal nonspecific immunoglobulin G, chemotactic peptides, interleukins, chemokines, and liposomes, have been used to image inflammation. Also, (99m)Tc nanocolloid scintigraphy has been found to be suitable for bone and joint diseases, especially RA. Among the single photon emitting imaging agents, the recommended radiotracer for abdominal inflammation has been (99m)Tc-hexamethylpropylene amine oxime (HMPAO)-labeled leukocytes. During the last several years, FDG-PET imaging has been shown to have great value for the detection of inflammation and has become the centerpiece of such initiatives. This very powerful technique will play an increasingly important role in the management of patients with inflammatory conditions. FDG-PET can provide valuable information in patients with pulmonary and extrapulmonary sarcoidosis, and is a useful tool for testing the efficacy of various treatments. FDG-PET combined with computed tomography holds great promise for assessing atherosclerosis of the large arteries. This modality is very sensitive in detecting large-vessel vasculitis and can be used to monitor the disease course. FDG-PET is also being used to study the inflamed synovial joints both in the experimental and clinical settings, especially for the investigation and management of RA and degenerative joint disease. This technique also has the potential to become the imaging modality of choice in assessing IBD, replacing radiolabeled autologous leukocyte imaging in this setting. Detection of inflammation in the lungs and airways may improve our knowledge about a multitude of disorders that affect these structures. Therefore, functional imaging, led by FDG-PET imaging, is likely to play an increasingly critical role in assessing inflammatory disorders of known and unknown etiologies, and will improve their management immensely in the future.

Imaging for the diagnosis of thyroid cancer.

BACKGROUND: There has been considerable difference in the mode of the imaging procedure and approach for the workup and post-surgery surveillance of thyroid cancer. Determination of serum thyroglobulin is recommended in the follow-up for monitoring the patients with differentiated thyroid carcinoma. Herein, the precise clinical role of individual imaging modalities is discussed, including ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI) and scintigraphic procedures for the diagnosis of recurrent or metastatic thyroid cancer. METHOD: A review is presented of the scientific papers published in the literature between 1982 and 2007. Relevant articles for this review were identified by searching PubMed using the following search terms: thyroid cancer, ultrasound, computerized tomography, magnetic resonance imaging and scintigraphy. The papers were analyzed and categorized in tabular form by date, subject, author and the type of scientific paper (e.g., randomized controlled trial, meta-analysis, clinical cases and review articles). CONCLUSION: Sonographic features of malignancy include microcalcifications, solid mass, absence of halo and internal blood flow, and these are helpful to predict thyroid malignancy in a nodule. Ultrasound is used for guiding fine needle aspiration to improve the accuracy of cytological analysis. However, biopsy is often necessary for a definitive diagnosis. This modality is also useful for postoperative neck evaluation of patients with elevated serum thyroglobulin levels to search for local recurrence or regional lymph node metastasis, which are the most common sites of recurrence. Tumor extension to the neighboring musculature, trachea, larynx and retropharyngeal, parapharyngeal and retrotracheal nodes are better defined by other anatomical imaging methods, such as CT or MRI. Anatomical imaging procedures are highly sensitive but not specific for postoperative evaluation of these patients and have few implications for deciding on subsequent I-131 therapy in patients with differentiated thyroid carcinoma. In addition to radioiodine scan, which has been the cornerstone of managing patients with differentiated thyroid cancer, nuclear imaging (scintigraphy) with technetium-99m sestamibi and tetrofosmin have all been used for determination of recurrent or metastatic differentiated thyroid cancer. Meta-iodo-benzylguanidine labeled either with I-123 or with I-131, 99mTc sestamibi and tetrofosmin and In-111 labeled somatostatin receptor analogues have been used for determination of recurrent or metastatic disease of medullary thyroid cancer. Over the last decade, positron emission tomography using 18-F-fluorodeoxyglucose has emerged as a useful tool in detecting non-iodine avid dedifferentiated and/or poorly differentiated thyroid cancer and plays a principal role in such settings.