Matthew F. Covington

Accuracy of Unenhanced MR Imaging in the Detection of Acute Appendicitis: Single-Institution Clinical Performance Review

PURPOSE To determine the accuracy of unenhanced magnetic resonance (MR) imaging in the detection of acute appendicitis in patients younger than 50 years who present to the emergency department with right lower quadrant (RLQ) pain. MATERIALS AND METHODS The institutional review board approved this retrospective study of 403 patients from August 1, 2012, to July 30, 2014, and waived the informed consent requirement. A cross-department strategy was instituted to use MR imaging as the primary diagnostic modality in patients aged 3-49 years who presented to the emergency department with RLQ pain. All MR examinations were performed with a 1.5- or 3.0-T system. Images were acquired without breath holding by using multiplanar half-Fourier single-shot T2-weighted imaging without and with spectral adiabatic inversion recovery fat suppression without oral or intravenous contrast material. MR imaging room time was measured for each patient. Prospective image interpretations from clinical records were reviewed to document acute appendicitis or other causes of abdominal pain. Final clinical outcomes were determined by using (a) surgical results (n = 77), (b) telephone follow-up combined with review of the patients medical records (n = 291), or (c) consensus expert panel assessment if no follow-up data were available (n = 35). Logistic regression analysis was performed to evaluate the sensitivity and specificity of MR imaging in the detection of acute appendicitis, and corresponding 95% confidence intervals were determined. RESULTS Of the 403 patients, 67 had MR imaging findings that were positive for acute appendicitis, and 336 had negative findings. MR imaging had a sensitivity of 97.0% (65 of 67) and a specificity of 99.4% (334 of 336). The mean total room time was 14 minutes (range, 8-62 minutes). An alternate diagnosis was offered in 173 (51.5%) of 336 patients. CONCLUSION MR imaging is a highly sensitive and specific test in the evaluation of patients younger than 50 years with acute RLQ pain that uses a rapid imaging protocol performed without intravenous or oral contrast material.

Classification Schema of Symptomatic Enterogastric Reflux Utilizing Sincalide Augmentation on Hepatobiliary Scintigraphy

Enterogastric reflux (EGR) is the reflux of duodenal contents into the stomach. Hepatobiliary scintigraphy provides physiologic assessment of the biliary system and was used to test the hypothesis that presence and timing of EGR may be associated with infusion of sincalide, a surrogate of endogenous cholecystokinin. Methods: One hundred fifty-seven hepatobiliary scintigraphy studies were retrospectively reviewed. Data included EGR incidence on initial reports, incidence after masked second reads, and time of EGR onset in relation to sincalide infusion. EGR cases were then classified according to onset on pre-, post-, or both presincalide and postsincalide imaging. Results: Time of EGR onset at 19–24 minutes after start of a 15-min sincalide infusion differed significantly from normal (p<0.0001). EGR was initially reported in 14 of 157 cases (8.9%) but found in 38 of 157 cases on masked second reads (24.2%), corresponding to a 15.3% discrepancy rate. Conclusion: The temporal association of EGR onset with sincalide infusion may identify patients with EGR mimicking chronic cholecystitis or biliary dyskinesia. A novel classification schema was therefore developed as a framework for future research, utilizing EGR onset in relation to pre-, post-, or both presincalide and postsincalide imaging as a hypothetical biomarker of clinically significant EGR.

The Semicolon Sign: Dopamine Transporter Imaging Artifact from Head Tilt

Dopamine transporter (DAT) imaging is a valuable tool to aid in the diagnosis of Parkinson disease and other Parkinsonian syndromes. DAT imaging is special among clinical nuclear medicine scans in that the already small caudate and putamen are presented in multiple thin axial cuts. Because the imaged basal ganglia are small, slight differences in head tilt may result in a significant artifact that we have termed the semicolon sign. The semicolon sign occurs when forward head tilt creates select images that show the caudate nuclei separate from the putamen. This gives the false impression that DAT activity in the putamen is decreased or absent. To avoid falsely attributing this artifact to loss of putaminal activity, it is imperative that the interpreting physician first recognize the artifact and then mentally integrate all provided images to identify normal activity in the putamen on subsequent levels. Furthermore, quantitative software packages for automated DAT scan interpretation are now available. If images demonstrating the semicolon sign are used for automated interpretation, loss of activity in the putamen may be falsely calculated, thereby contributing to erroneous results. Quality control measures are essential to ensure that technologists correctly position each patient’s head to minimize head tilt artifact on DAT scan images. A protocol to obtain optimal head positioning is presented.

FDG-PET/CT for Monitoring Response of Melanoma to the Novel Oncolytic Viral Therapy Talimogene Laherparepvec

61-year-old woman with stage IIIa (T3a N1a M0) left lower leg melanoma with lesions suggestive of in-transit metastases 8 months following wide local excision and femoral nodal dissection. FDG-PET/CT demonstrated 5 FDG-avid in-transit nodal metastases in the distal left leg, confirmed on biopsy. Talimogene laherparepvec (T-VEC) oncolytic immunotherapy consisting of intralesional injections of modified herpes simplex virus-expressing granulocyte-macrophage colony-stimulating factor was completed over 6 months. Subsequent FDG-PET/CT demonstrated reduced or resolved FDG activity in the treated in-transit metastases and a new FDG-avid left thigh in-transit metastasis. FDG-PET/CT can monitor response to T-VEC and potentially other novel viral immunotherapies.

Patient Survey on Satisfaction and Impact of 123I-Ioflupane Dopamine Transporter Imaging.

Patients were surveyed to assess the impact of dopamine transporter imaging on diagnostic confidence, change in treatment plan, effect on medication compliance, and subjective well-being. Surveys were sent to 140 patients who completed dopamine transporter imaging an average of 18 months prior. Sixty-five surveys from patients (46%) were returned. Questions assessed patients’ perceived impact of the imaging on their care. Increased diagnostic confidence following imaging was reported by 69% of patients. Changes to treatment plan from imaging were reported by 24% of patients. Overall satisfaction with the study and its impact was reported by 70% of patients. Dopamine transporter imaging increased diagnostic confidence among patients and overall patient satisfaction with the impact of imaging on clinical care was high.

Adjusting ACR Appropriateness Criteria for Novel Radiopharmaceuticals

Adjusting ACR Appropriateness Criteria for Novel Radiopharmaceuticals According to the ACR website, the ACR Appropriateness Criteria (AC) are “evidence-based guidelines to assist referring physicians and other providers in making the most appropriate imaging or treatment decision for a specific clinical condition.” The initial intent of the AC was to “create guidelines for radiology to eliminate inappropriate utilization of radiologic services” [1]. AC guidelines were recently published for dementia and movement disorders [2]. Within these guidelines were recommendations regarding the use of amyloid PET/CT and I ioflupane SPECT (dopamine transporter imaging), the newest FDA-approved radiopharmaceuticals. These guidelines may contradict other published evidencebased guidelines in specific use scenarios, leading to confusion for clinicians, radiologists, and patients. Determining the appropriate use of new radiopharmaceuticals may require a different methodology than is conventionally applied to imaging such as MRI or CT of the head. These nuclear radiologic studies belong under the umbrella of precision medicine wherein imaging evaluates a specific pathology. For example, amyloid PET/CT demonstrating absent to sparse amyloid plaque effectively excludes the neuropathologic consideration of Alzheimer’s disease [3]. For I ioflupane, abnormal findings aid in differentiating the diagnosis of Parkinson’s disease or a parkinsonian syndrome from essential tremor,

Impact of Reimbursement Cuts on the Sustainability and Accessibility of Dopamine Transporter Imaging

PURPOSE Dopamine transporter single-photon emission computed tomography imaging utilizing iodine-123 ioflupane is accurate for differentiation of Parkinson disease from essential tremor. This study evaluates how reimbursement for I-123 ioflupane imaging changed between 2011 (year of FDA approval) and 2014 (year after loss of pass-through status for hospital-based outpatient imaging from CMS). METHODS I-123 ioflupane reimbursement data for our institutions hospital-based imaging were compared between two periods: (1) July 2011 to October 2012, and (2) 2014. For each time period separately and in combination, averages and ranges of reimbursement for private insurance and CMS were analyzed and compared. A model to ensure recouping of radiopharmaceutical costs was developed. RESULTS Review yielded 247 studies from July 2011 to October 2012 and 94 studies from 2014. Average reimbursement per study fell from

A Graduate's Perspective on the ABR Dual Certification Pathway in Nuclear Radiology and Diagnostic Radiology.

2,469 (US dollars) in 2011 to 2012 to

Optimal Time Points for Scintigraphic Imaging of Pleuroperitoneal Shunts.

1,657 in 2014. CMS reduced average reimbursement by

Pitfalls in the Performance and Interpretation of Scintigraphic Imaging for Pleuroperitoneal Shunt

1,148 in 2014 because of loss of radiopharmaceutical pass-through status. Average reimbursements from CMS versus private payors markedly differed in 2011 to 2012 at