Outpatient Computed Tomography Research Articles

Modelling a Computed Tomography service using mixed Operational Research methods

ABSTRACT Demand for computed tomography (CT) and CT waiting lists are growing, a problem exacerbated by the postponement of scheduled services during the Covid-19 pandemic. In this case study operational research (OR) methods were used to investigate resource utilisation and CT waiting list growth. Stakeholder involvement was facilitated using system dynamics (SD) for problem conceptualisation and Soft Systems Methodology (SSM) to identify service issues, data requirements, and scenarios for testing. Discrete event simulation (DES) was used to generate metrics pertaining to daily staff work load, process performance (delays) and waiting list evolution, for the current and alternative scenarios. Lessons learnt from the perspective of a clinical modeller are discussed throughout. DES model outputs illustrated the high daily variation in resource utilisation and process delays for the current service where inpatients and outpatients share a single CT scanner. Inpatient examinations were found to consume on average 23% more staff time than outpatient. For non-contrast CT scans, outpatients consumed 63% less time than inpatients. Simulation results for an outpatient-only service demonstrated higher CT and healthcare assistant utilisation, with low variation and process delays. This work recommends the separation of inpatient and outpatient CT services to address the problem of growing CT waiting lists.

1607P Trends in cancer imaging by indication, care setting, and hospital type during the COVID-19 pandemic and recovery

Background: The delivery of cancer care has been greatly affected by the COVID pandemic. We aim to investigate the effect of the pandemic on computed tomography (CT) imaging of cancer. Methods: Cancer-related CT exams were retrospectively analyzed during three periods of 2020: pre-COVID (1/5/20-3/14/20), COVID peak (3/15/20-5/2/20) and post-COVID peak (5/3/20-11/14/20). Volumes were assessed by 1) Imaging indication: cancer screening, initial workup, active cancer, surveillance;2) Care setting: outpatient, inpatient, ED;3) Hospital type: quaternary academic center (QAC), university-affiliated community hospital (UACH), sole community hospitals (SCHs). Results: During the COVID peak, a significant drop in CT volumes was observed (-42·2%, p<0·0001), with cancer screening, initial workup, active cancer and cancer surveillance experiencing declines by 81·7%, 54·8%, 30·7% and 44·7% respectively (p<0·0001, Figure 1). The emergency department (ED) was the only setting with stable cancer-related CT volumes. In the post-COVID peak period, CT volumes for cancer screening and for initial workup did not recover (-11·7%, p=0·037;-20·0%, p=0·031), with the outpatient setting particularly affected. CT volumes for active cancer recovered post-peak, but inconsistently across hospital types with the QAC experiencing a 9·4% decline (p=0·022) and the UACH a 41·5% increase (p<0·001). Outpatient CTs recovered during the post-peak period, but a shift in utilization away from the QAC (-8·7%, p=0·020) toward the UACH (+13·3%, p=0·013) was observed. Inpatient and ED-based cancer-related CTs increased post-peak (+20·0%, p=0·004 and +33·2%, p=0·009, respectively). Conclusions: COVID severely impacted cancer imaging care. CTs for cancer screening and initial workup did not recover to pre-COVID levels well into 2020, a finding that suggests higher numbers of patients with advanced cancers may present in the future. A redistribution of imaging utilization away from the QAC and outpatient settings, toward the community hospitals and inpatient setting/ED was observed. The ED has remained a dependable healthcare delivery setting for patients with cancer throughout the pandemic. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: J. Brink: Financial Interests, Institutional, Member of the Board of Directors: Accumen, Inc. All other authors have declared no conflicts of interest.

The clinical utility of inpatient MRI following an abdominopelvic CT.

The purpose of this study was to assess the diagnostic yield of abdomen magnetic resonance imaging (MRI) in the inpatient setting following a computed tomography (CT). All inpatient abdominopelvic MRIs performed on patients for a 1-year period were identified and medical records were retrospectively reviewed for the following information. Only MRIs with a preceding CT were included in the study. A total of 221 MRIs were included. Forty exams were deemed technically inadequate due to motion, while 9 more patients did not tolerate a full examination. The most common indications were focal liver lesion (n = 101), pancreaticobiliary ductal dilatation (n = 39), abnormal liver function tests (n = 26), acute pancreatitis (n = 14), abdominal pain (n = 10), and fever/sepsis (n = 10). 83 MRIs were recommended on CT and 138 were requests from the care team. In 63 cases, MRI offered new information over CT. Thirty-two MRIs recommended by radiologists affected patient management, while only 31 MRIs recommended by the care team affected management. Of these 63 MRIs, 29 cases changed immediate inpatient management, requiring further intervention. In these cases, MRI identified abscesses, choledocholithiasis, or made other diagnoses such as cholecystitis, which were not diagnosed on CT. Patient LOS increased in 24 patients in order to receive an MRI. Average costs of outpatient CTs and MRIs are typically 20% less than inpatient costs. Inpatient abdomen MRIs have limited impact on patient care following a CECT and entail higher cost, utilize more resources, scanner time, and increase patient LOS. Therefore, it should be reserved for select clinical indications.

Trends in cancer imaging by indication, care setting, and hospital type during the COVID-19 pandemic and recovery at four hospitals in Massachusetts.

BackgroundWe aimed to investigate the effects of COVID‐19 on computed tomography (CT) imaging of cancer.MethodsCancer‐related CTs performed at one academic hospital and three affiliated community hospitals in Massachusetts were retrospectively analyzed. Three periods of 2020 were considered as follows: pre‐COVID‐19 (1/5/20–3/14/20), COVID‐19 peak (3/15/20–5/2/20), and post‐COVID‐19 peak (5/3/20–11/14/20). 15 March 2020 was the day a state of emergency was declared in MA; 3 May 2020 was the day our hospitals resumed to non‐urgent imaging. The volumes were assessed by (1) Imaging indication: cancer screening, initial workup, active cancer, and surveillance; (2) Care setting: outpatient and inpatient, ED; (3) Hospital type: quaternary academic center (QAC), university‐affiliated community hospital (UACH), and sole community hospitals (SCHs).ResultsDuring the COVID‐19 peak, a significant drop in CT volumes was observed (−42.2%, p < 0.0001), with cancer screening, initial workup, active cancer, and cancer surveillance declining by 81.7%, 54.8%, 30.7%, and 44.7%, respectively (p < 0.0001). In the post‐COVID‐19 peak period, cancer screening and initial workup CTs did not recover (−11.7%, p = 0.037; −20.0%, p = 0.031), especially in the outpatient setting. CT volumes for active cancer recovered, but inconsistently across hospital types: the QAC experienced a 9.4% decline (p = 0.022) and the UACH a 41.5% increase (p < 0.001). Outpatient CTs recovered after the COVID‐19 peak, but with a shift in utilization away from the QAC (−8.7%, p = 0.020) toward the UACH (+13.3%, p = 0.013). Inpatient and ED‐based oncologic CTs increased post‐peak (+20.0%, p = 0.004 and +33.2%, p = 0.009, respectively).ConclusionsCancer imaging was severely impacted during the COVID‐19 pandemic. CTs for cancer screening and initial workup did not recover to pre‐COVID‐19 levels well into 2020, a finding that suggests more patients with advanced cancers may present in the future. A redistribution of imaging utilization away from the QAC and outpatient settings, toward the community hospitals and inpatient setting/ED was observed.

Utility of Head Computed Tomography Scans Before Outpatient Follow-up for Low-Risk Mild Traumatic Brain Injury

Neurosurgeons are frequently consulted for traumatic brain injuries (TBIs) resulting in intracranial hemorrhage (ICH). After inpatient confirmation of hemorrhage stability, outpatient head computed tomography (CT) is often performed to assess for hemorrhage resolution. Our objective was to assess the practice patterns and clinical utility of routine outpatient head CT scans for patients with mild TBI (mTBI). A retrospective review was performed on all adult mTBI patients with ICH who presented to a level I trauma center over a 4-year period. A combination of the patient's initial clinical evaluation and CT findings was used to identify mTBI patients at low risk for neurologic deterioration and neurosurgical intervention. Findings from the outpatient follow-up clinical evaluation and head CT were assessed. Patients without outpatient follow-up within 3 months were excluded. Forty-nine patients met inclusion criteria for the study. Thirty-two had an outpatient head CT before their follow-up appointment. Twenty-one patients had at least 1 neurologic finding at the earliest follow-up appointment. All patients except those with a subdural hematoma (SDH) had smaller or resolving ICH on outpatient CT scans. Seven patients with an SDH had unchanged or expanded hemorrhage on outpatient imaging, 2 of whom had traumatic brain injury-related hospitalizations and 1 of whom underwent neurosurgical intervention due to an enlarging SDH. Routine outpatient head CT scans before follow-up for low-risk mTBI patients without an SDH appears to have limited clinical utility. In low-risk mTBI patients with an SDH, obtaining an outpatient head CT is reasonable to monitor for resolution.

Improving Language Service Access for Patients with Limited English Proficiency in the Outpatient CT Department

In the outpatient Computed Tomography (CT) imaging department at Sunnybrook Health Sciences Centre, patients with limited English proficiency (LEP) and healthcare providers often face significant challenges in communication during exams with contrast administration. While family members and bilingual staff can help interpret, there are concerns over patient confidentiality, accuracy of medical translation, and patient safety.

300. Computed tomography use in a large italian region: Trend analysis 2004–2014 of emergency and outpatient CT examinations in children and adults

Purpose To analyse Computed Tomography (CT) use in recent years in a high population density area in Italy (approximately 10 million inhabitants, including 1 million children), focusing on the developing age. Methods and materials Retrospective analysis of records from the Health Care IT System, covering more than 400 hospitals and clinics. Description of CT use between 2004 and 2014 in emergency and outpatient care and assessment of the radiation exposure trend. Results Over 9 million scans were performed. Emergency procedures showed a global increase of 230%, which mainly consisted of Head exams. In the global outpatient setting, the annual number of CT scans per person increased approximately 19%. A moderate increase in CT exams was observed in the developing age population, while a remarkable increase in Dental, Chest and Abdominal procedures occurred within the 10–30-year age range. The increase in the mean annual dose per caput in the global patient pool was approximately 42%, increasing from 0.72 mSv to 1.03 mSv. The population rate that received an annual radiation dose per caput from CT higher than 1 mSv tripled in the 11-year interval, increasing from 16 to 48%. Conclusion The outcomes raise a special concern for teenagers and young adults, taking into account that the widespread use of CT represents probably the single most important achievement in diagnostic radiology. The increase in CT use and in the CT-derived radiation dose in the population is occurring in spite of the evidence of the substantially improved carcinogenic potential of low doses of X-ray radiation, particularly for children. In contrast with several published investigations, which underline the radiation risk for paediatric age, the level of detail of the data processed in this study highlights a remarkable increase in the irradiation of teenagers and young adults, whose risk tends to be underestimated.

Computed Tomography Colonography vs Colonoscopy for Colorectal Cancer Surveillance After Surgery

Recommendations for surveillance after curative surgery for colorectal cancer (CRC) include a 1-year post-resection abdominal-pelvic computed tomography (CT) scan and optical colonoscopy (OC). CT colonography (CTC), when used in CRC screening, effectively identifies colorectal polyps ≥10 mm and cancers. We performed a prospective study to determine whether CTC, concurrent with CT, could substitute for OC in CRC surveillance. Our study enrolled 231 patients with resected stage 0-III CRC, identified at 5 tertiary care academic centers. Approximately 1 year after surgery, participants underwent outpatient CTC plus CT, followed by same-day OC. CTC results were revealed after endoscopic visualization of sequential colonic segments, which were re-examined for discordant findings. The primary outcome was performance of CTC in the detection of colorectal adenomas and cancers using endoscopy as the reference standard. Of the 231 participants, 116 (50.2%) had polyps of any size or histology identified by OC, and 15.6% had conventional adenomas and/or serrated polyps ≥6 mm. No intra-luminal cancers were detected. CTC detected patients with polyps of ≥6 mm with 44.0% sensitivity (95% CI, 30.2-57.8) and 93.4% specificity (95% CI, 89.7-97.0). CTCdetected polyps ≥10 mm with 76.9% sensitivity (95% CI, 54.0-99.8) and 89.0% specificity (95% CI, 84.8-93.1). Similar values were found when only adenomatous polyps were considered. The negative predictive value of CTC for adenomas ≥6 mm was 90.7% (95% CI, 86.7-94.5) and for adenomas ≥10 mm the negative predictive value was 98.6% (95% CI, 97.0-100). In a CRC surveillance population 1 year following resection, CTC was inferior to OC for detecting patients with polyps ≥6 mm. Clinical Trials.gov Registration Number: NCT02143115.

139 Admit or Discharge: Management of Incidental Pulmonary Embolism in an Emergency Center

It is common for incidental pulmonary emboli (IPE) to be detected by computed tomography (CT) scans performed during a cancer evaluation. Our purpose was to describe outcomes in cancer patients presenting to an emergency department (ED) with a diagnosis of IPE. Retrospective chart review of patients presenting to the ED of a major cancer hospital from Jan 1, 2013 to Dec 31, 2014. Eligibility criteria included all age >18 y cancer patients undergoing an out-patient lung CT scan for cancer staging. Exclusion criteria were patients with known pulmonary embolism (PE) within 1 year prior, on anticoagulation therapy for Venous Thromboembolism (VTE), CT scan obtained for suspected PE, against medical advice discharge, or being a non-malignant cancer patient. Medical records were reviewed and data extracted for demographics, cancer type and stage, comorbidities, performance status, vitals, location of the emboli, anticoagulation, ED disposition, and cause of death. Of 1411 newly diagnosed PE patients during the study period, 208 (15%) presented to the ED met the entry criteria of IPE found during routine cancer staging. Of IPE patients, 15 were excluded (12 recurrent PE, 1 benign tumor, and 2 left against medical advice). Of the study cohort consisting of 193 patients, 111 (58%) were male, mean age was 63.37 years (SD=12.09), 139 (72%) were white, 27 (14%) black, 17 (9%) Hispanic, and 10 (5%) of other race/ethnicity. The majority of IPE patients had solid tumors (n=174, 90%) and 69% of patients (n=133) were discharged home on low molecular weight heparin. Cox regression analysis showed that sex, race, Charlson Comorbidity Index (age unadjusted), cancer stage, performance status, tachycardia, hypoxia and location of the emboli were associated with hospital admission. Admitted patients were more likely to die within 30 days, 16 of 60 (27%), than discharged patients, 0 (0%, Fisher exact test; p<0.001). Half of the admitted patients died within 180 days compared with 25 of 133 (19%) of the discharged patients (p<0.001). The risk of death within 30 days was higher if the emboli was located in the saddle or main pulmonary artery (PA) (40%) than those with lobar, segmental or sub-segmental PA (10%, 6% and 5 %, respectively). Multivariate analyses suggest that tachypnea and location of the emboli are associated with 30 day survival (p<0.05), and that performance status and location of the emboli are associated with 180 day survival and overall survival (p<0.05 for all). A cohort of selected ED cancer patients diagnosed with IPE may be identified for outpatient anticoagulation treatment and may be safely discharged.

Urinary iodine excretion and serum thyroid function in adults after iodinated contrast administration.

Iodinated contrast media (ICM) is a source of excess iodine that may induce thyroid dysfunction. A prospective cohort study was conducted to assess the effects of ICM on urinary iodine clearance and serum thyroid function tests (TFTs) in adults. In this prospective cohort study of 54 adults undergoing elective computed tomography (CT) scans at an academic medical center, serial urinary iodine concentrations (UIC) and serum TFTs were obtained until UIC normalized following ICM administration. Thyroid volume/nodularity were assessed by ultrasound. Associations between covariates and peak UIC, duration for UIC to peak and normalize, and thyroid dysfunction risk were assessed. The mean±standard deviation (SD) iodine administered was 34.6±6.0 g. Baseline median (range) UIC was 105.1 (17.0-866.1) μg/L, and serum thyrotropin (TSH) concentration was 1.26 (0.5-11.2) mIU/L. The mean±SD times to achieve peak UIC (median [range]: 3519 [233-157,500] μg/L] and normalized UIC were 1.1±0.5 and 5.2±4.0 weeks, respectively. Four subjects had elevated baseline TSH, and one had missing baseline TSH values. Of the remaining 49 subjects, 11 (22%) developed an abnormal TSH within one to four weeks (six elevated and five decreased). Administered iodine amount correlated with peak UIC following ICM administration (p<0.001). Increasing age and administered iodine amount predicted peak UIC (p=0.024 and p<0.001, respectively). Age, sex, race/ethnicity, smoking status, family history of thyroid disease, personal or family history of thyroid autoimmunity, thyroid volume, presence of thyroid nodules ≥1 cm, iodine dose, baseline UIC, and baseline TFTs were not predictive of durations to achieve peak or normalized UIC. Peak UIC occurred at 1.1 weeks and normalized by 5.2 weeks following ICM administration for outpatient CT scans. Because thyroid dysfunction developed in 22% of individuals following a single ICM dose, monitoring of thyroid function should be considered in at-risk patients.

Assessing the Appropriateness of Outpatient Abdominopelvic CT and MRI Examinations Using the American College of Radiology Appropriateness Criteria

To retrospectively assess the appropriateness of outpatient abdominal and pelvic computed tomography (CT) and magnetic resonance imaging (MRI) examinations using the American College of Radiology Appropriateness Criteria (AC). A total of 570 adult outpatient abdominopelvic CT (304) and MRI (266) studies performed in a 1-month period with available documentation of the clinical encounter generating the imaging order were included. On the basis of review of the imaging report and patient record, examinations were classified in terms of match to a specific AC variant, appropriateness score, and the presence of a significant result. Data were analyzed using Fisher's exact test. Forty-five percent of examinations matched an AC variant: 52% of CT and 38% of MRI (P<.001). Ninety-two percent of examinations matching the AC were appropriate: 96% of CT and 86% of MRI (P=.009). Appropriate examinations were more likely to provide a significant result than not appropriate studies (48% vs. 24%, P=.041). Although a significant result was related to the primary study indication more frequently in appropriate than not appropriate examinations, this difference was not significant (93% vs. 80%, respectively, P=.204). The most common indications not matching an AC were colon cancer follow-up (n=14) and melanoma follow-up (n=14) among CT, and hepatocellular carcinoma screening (n=31) and elevated prostate-specific antigen (PSA) without prior biopsy (n=14) among MRI. Most examinations matching the AC were appropriate, and appropriate examinations were more likely to have a significant result. However, most examinations, including 62% of MRI, had no relevant clinical condition, highlighting a critical area for future AC expansion and modification.

Traumatic injury of the thoracic aorta treated with stent-graft: Is long-term CT angiography follow-up justified?

To report the results of long-term (>5 years) computed tomography (CT) angiography follow-up after thoracic endovascular aortic repair in patients with traumatic thoracic aortic injury. All follow-up CT angiographies performed in patients with traumatic thoracic aorta injury treated by endovascular stent-graft between 2002 and 2008 were reviewed. Of the 14 patients treated, seven patients had CT angiography follow-up examinations for more than 5 years. All patients were men with a mean age of 26 years. The Talent device was used in four patients and Gore TAG device in three patients. The mean device diameter and length were 24.6 mm and 103 mm, respectively. Follow-up included annual outpatient clinic surveillance and CT angiography examinations, which were reviewed for any device-related complications. The radiation effective dose was calculated from the CT dose report. Thirty-three CT examinations performed 64-110 months (mean 76) after stent-graft implementation were reviewed. The mean follow-up number of examinations per patient was 4.7 (range 2-8). Intra-graft circular mural tissue at the distal part of the stent-graft was seen in one patient. Stable lack of proximal device apposition was seen in all patients. No other radiological complications (e.g., aortic infection, dilatation, aneurysm or pseudoaneurysm, device struts breakage, migration, collapse, endoleak) were detected. None of the patients developed hypertension. The average effective dose was 77.01 mSv (range 34.11-128.84 mSv). CT angiography did not reveal any complications developing throughout the long-term follow-up. These results suggest that long-term CT angiography follow-up may not be required.

Predictors of Excessive CT Scan Use in a Surgical Cohort of Patients With Crohn's Disease

Background: Patients with Crohn's disease typically undergo computed tomography (CT) scans periodically over the course of their chronic disorder, requiring only modest doses of ionizing radiation. However, previous studies have suggested there is a subgroup of patients with Crohn's disease who undergo frequent CT scans with an associated increase in health care expenditures and possible overexposure to radiation, potentially placing such patients at increased risk for cancer. The aim of our study was to characterize and define this potentially vulnerable cohort using a relatively homogeneous surgical population. Methods: Consecutive patients who underwent ileocolic resection for Crohn's disease from January 2000 to September 2010 at an academic medical center were identified from a prospectively maintained database. Only patient CT scans remote from surgery or hospitalization were considered in the analysis. The number of outpatient CT scans, physician visits, and coexisting psychiatric and functional diagnoses were recorded from retrospective chart review. Patients who were considered high CT scan utilizers were compared with patients who were low utilizers. Results: Sixty-three patients underwent 126 CT scans during the study period, however, 4 of the patients accounted for 52 (41%) of the studies. Compared with the overall study population, the subset of 4 patients (high utilizers) had a median of 66 clinic visits (P < 0.001) and 40 emergency department visits (P < 0.001). All 4 patients were on chronic narcotic medication, and only 1 did not have a concomitant functional disorder. Missed appointments and the absence of prescribed antidepressants were common among patients with high CT use. Conclusions: Although use of CT appears moderate in surgical patients with Crohn's disease overall, there is a subset of patients with chronic pain and psychiatric diagnoses, who frequently miss appointments, and account for a markedly disproportionate number of scans performed. Interestingly, use of antidepressants in patients with Crohn's disease was strongly associated with fewer scans, suggesting an opportunity for therapeutic intervention.

Infected Branchial Cleft Cyst Presenting as a Recurrent Peritonsillar Abscess

Objective: Peritonsillar abscess (PTA) is the most common deep infection of the head and neck in young adults. The incidence of recurrent unilateral PTA is extremely low, and a patient with recurrent unilateral PTA development deserves a more vigorous workup for other pathologic entities, including branchial cleft cysts (BCC). Method: We describe a unique clinical case illustrating the workup and diagnosis of a patient presenting with “recurrent unilateral PTA” that actually turned out to be a second BCC. We discuss the necessity to keep a broad differential when evaluating patients presenting with “classic” symptomatology. Results: A 40-year-old male presented to the emergency department with a history of 5 previous right-sided PTAs. The patient was again treated for “recurrent PTA” due to computed tomography (CT) scan and physical examination findings. An outpatient CT scan later showed a residual fluid collection in the peritonsillar and parapharyngeal space. The patient was subsequently taken to the operating room for a definitive exploration where a second BCC was discovered and removed. Conclusion: BCCs may be asymptomatic but commonly present as recurrent infected neck abscesses. In any patient who presents with recurrent unilateral PTAs, a broader differential diagnosis should be formulated (including BCC), and necessary imaging studies should be ordered to properly classify and treat these individuals.

Variability of radiation exposure with in‐office sinus computed tomography examinations

An increasing number of patients seeking care by an otolaryngologist are undergoing computed tomography (CT) examinations via in-office CT scanners. Many otolaryngologists and patients are not fully aware of the radiation dosages and the associated risks. A recent study of common CT examinations demonstrated significant variability in radiation dosages for similar studies. Despite the relatively low doses associated with sinus scans, widely publicized studies and events have generated a renewal of physician, public, and regulatory agency awareness and concern regarding medical radiation exposure. Phantom measurements and/or radiation dosage reports from CT scanners utilized by a large otolaryngology group in California were reviewed and compared. Different types of CT scanners from multiple manufacturers were included. There was nearly a 10-fold difference (0.15-1.45 mSv) in radiation between scans obtained from in-office, hospital-based, and outpatient imaging facility CT scanners. Significant relative variability can exist in radiation dosages associated with routine sinus CT scans obtained in different locations. There is a need for increased awareness and understanding among otolaryngologists and their patients regarding medical radiation exposure. All otolaryngologists should constantly consider the principle of "as low as reasonably achievable" (ALARA). Shielding, pediatric protocols, and other dosage reduction measures should be utilized whenever possible.

Patterns of Care and Outcomes After Computed Tomography Scans for Headache

Background Concerns exist about potential overuse of computed tomography (CT) scans for headache in ambulatory care. Methods We sought to examine health services use, brain tumor diagnosis, and death during the year after CT scanning for headache by linking records of an audit of 3930 outpatient CT brain scans performed in 2005 in Ontario, Canada, to administrative databases. Results Of 623 patients receiving CT scans for a sole indication of headache, few (2.1%) scans contained findings potentially causing their headache. For most patients, the index CT scan was the only one received over an 11-year period. However, 28.4% of patients received 1 or more CT brain scans during the preceding decade and 6.7% received 1 or more CT brain scans during the subsequent year. Of the 473 patients (75.9%) whose index scan was ordered by a primary care physician, most (80.3%) did not see a specialist during follow-up. One patient with an indeterminate finding on the index scan was diagnosed with a malignant brain tumor (0.2%), and 6 patients (1.0%) died during follow-up. Among the 4 deaths in which the cause could be determined, none were due to central nervous system causes. Conclusion Because of the potential risk of cancer from exposure to ionizing radiation, efforts should be made to avoid CT scanning for headache when the likelihood of serious illness is low. Evidence-based decision rules that identify which patients with headache do not require neuroimaging may decrease the use of CT scans in situations of little benefit.

Non-adherence to Recommendations for Further Testing after Outpatient CT and MRI

Background Nearly 1 in every 5 outpatient visits ends with a request for a diagnostic imaging test, and imaging reports often contain recommendations for further testing. Little is known about adherence to recommendations for further testing after outpatient computed tomography (CT) and magnetic resonance imaging (MRI). Methods We performed a retrospective cohort study linking provincial administrative data to a cross-sectional audit of 23,691 outpatient CT and MRI scans performed in 2005 in Ontario, Canada. After excluding patients who died (n = 1031), were hospitalized (n = 3030), or visited an emergency department (n = 3660) within 180 days of the index CT/MRI scan, 15,970 CT/MRI scans were included. The primary outcome was adherence to recommendations for further testing within 180 days of an index CT/MRI scan. Results Further testing was recommended in 2027 of 15,970 (12.7%) index CT/MRI scan reports and was recommended most frequently after CT chest scans (593 of 2276 [26.1%]). From the 2027 scans in which further testing was recommended, we identified 2102 individual recommendations for a specific type of follow-up test and found that just over one third (37.6%) of these recommendations were followed at 180 days. Adherence was lower (32.3%) when patients had a visit to the referring physician within 180 days of the index CT/MRI scan, compared with when they had no such visit (50.5%; P <.001). Conclusions Radiologists commonly recommend further testing after outpatient CT and MRI scanning. However, nearly two thirds of these recommendations are not followed. This suggests that substantial opportunities exist to improve the exchange of information between clinicians and radiologists and to advance the quality of outpatient care.

Dyspnea and Multiple Pulmonary Nodules

Dr. Adam Levine: Today's case is that of a 67-year-old man, a retired physician of Indian origin, who was referred to the emergency department (ED) by his primary care physician for a 2-day history of increasing shortness of breath and an outpatient computed tomography (CT) scan that showed multiple pulmonary nodules. The patient stated that he was well until 2 months previously, when he acutely developed lower back pain. His primary care physician ordered magnetic resonance imaging (MRI) of the lumbar spine, which showed L2/3 spinal stenosis. The patient subsequently received steroid injections on two occasions. Of note, he reported receiving significant dental work during the same time period. A week after the spinal injections, the patient developed a low grade fever and night sweats. He began to suffer from continuous back pain and stiffness as well as pain in the pelvic girdle. The primary care physician noted an erythrocyte sedimentation rate (ESR) of 70 mm/hour and diagnosed him with polymyalgia rheumatica. She started him on 20 mg prednisolone QD (daily), but the patient noticed no substantial improvement after 1 week's use. He subsequently developed jaw pain and was referred to a rheumatologist, who diagnosed him with temporal arteritis and increased the dose of prednisolone to 60 mg QD. The fever subsided and the lethargy seemed to improve. However, 1 month preceding presentation to the ED, the patient became increasingly lethargic and lost 10–12 pounds. He developed dyspnea on exertion as well as a non-productive cough. The lethargy and dyspnea were evaluated by a hematologist, who ordered an outpatient chest CT scan and blood cultures. Several days later, the patient's dyspnea worsened acutely. The chest CT scan revealed multiple pulmonary nodules, and blood cultures grew “Gram-positive cocci in chains and pairs.” The patient was advised to proceed directly to the ED.

Esophageal Varices On Computed Tomography Predicts Variceal Hemorrhage

Background: Prior studies suggest good agreement between grading of esophageal varices (EV) by endoscopy and measurement by computed tomography (CT). No studies to date have correlated markers of portal hypertension on CT imaging and variceal hemorrhage (VH). Methods: A case-cohort study was performed using patients from San Francisco Veterans Affairs Medical Center with advanced liver disease identified by ICD-9 codes and an outpatient CT between January 2000 and December 2007. Twenty-four patients with an outpatient CT scan prior to sustaining a VH served as cases. Twenty five subjects with no history of VH and an outpatient CT and upper endoscopy within 90 days of each other from calendar 2005 served as controls. Patients were excluded if they had a prior history of band ligation, portal venous thrombosis, or suspected hepatocellular carcinoma. VH was confirmed by chart review, including typical clinical presentation and endoscopic findings at the time of hospitalization. CT scans were reviewed by an experienced radiologist for measurements of various markers of portal hypertension. Results: Patients with VH were more likely to have findings of portal hypertension. The most prominent factors associated with VH included EV tortuosity (100% vs. 40%, OR=∞, p<0.0001), any detectable EV (95.8% vs. 16%, OR=121, p<0.0001), and ascites (79% vs. 28%, OR=9.8, p=0.0003). Presence of paraesophageal varices, recanalized umbilical vein, and enlargement of the coronary vein were less strongly associated with VH. The size of the largest EV was significantly larger in patients experiencing a VH (4.89 mm vs. 0.68 mm, difference=4.2 mm, p<0.0001). The diameter of the portal vein, spleen size, MELD score, and age was not significantly different between the cases and the controls. The number of EV was the only independent predictor of VH in a multivariable logistic model (OR 3.90, range 0-6, p=0.018). The number of EV discriminated well between patients with VH versus those without VH (c statistic 0.95, 95% CI 0.89 - 1.0). Conclusion: The number of EV visualized by CT imaging discriminate well patients with advanced liver disease who are at elevated risk for VH.

Effect of Computerized Order Entry with Integrated Decision Support on the Growth of Outpatient Procedure Volumes: Seven-year Time Series Analysis

To determine the effect of a computerized radiology order entry (ROE) and decision support (DS) system on growth rate of outpatient computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US) procedure volumes over time at a large metropolitan academic medical center. Institutional review board approval was obtained for this study of deidentified aggregate administrative data. The research was compliant with HIPAA; informed consent was waived. This was a retrospective study of outpatient advanced imaging utilization before, during, and after implementation of a Web-based ROE and DS system. Dependent variables were the quarterly volumes of outpatient CT, MR imaging, and US examinations from quarter 4 of 2000 through quarter 4 of 2007. Outpatient visits during each quarter were included as control variables. These data were analyzed as three separate time series with piecewise linear regression for simultaneous estimation of quarterly examination volume trends before and after ROE and DS system implementation. This procedure was repeated with log-transformed quarterly volumes to estimate percentage growth rates. There was a significant decrease in CT volume growth (274 per quarter) and growth rate (2.75% per quarter) after ROE and DS system implementation (P < .001). For MR imaging, growth rate decreased significantly (1.2%, P = .016) after ROE and DS system implementation; however, there was no significant change in quarterly volume growth. With US, quarterly volume growth (n = 98, P = .014) and growth rate (1.3%, P = .001) decreased significantly after ROE implementation. These changes occurred during a steady growth in clinic visit volumes in the associated referral practices. Substantial decreases in the growth of outpatient CT and US procedure volume coincident with ROE implementation (supplemented by DS for CT) were observed. The utilization of outpatient MR imaging decreased less impressively, with only the rate of growth being significantly lower after interventions were in effect.