James H. Thrall

Addressing Overutilization in Medical Imaging

The growth in medical imaging over the past 2 decades has yielded unarguable benefits to patients in terms of longer lives of higher quality. This growth reflects new technologies and applications, including high-tech services such as multisection computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET). Some part of the growth, however, can be attributed to the overutilization of imaging services. This report examines the causes of the overutilization of imaging and identifies ways of addressing the causes so that overutilization can be reduced. In August 2009, the American Board of Radiology Foundation hosted a 2-day summit to discuss the causes and effects of the overutilization of imaging. More than 60 organizations were represented at the meeting, including health care accreditation and certification entities, foundations, government agencies, hospital and health systems, insurers, medical societies, health care quality consortia, and standards and regulatory agencies. Key forces influencing overutilization were identified. These include the payment mechanisms and financial incentives in the U.S. health care system; the practice behavior of referring physicians; self-referral, including referral for additional radiologic examinations; defensive medicine; missed educational opportunities when inappropriate procedures are requested; patient expectations; and duplicate imaging studies. Summit participants suggested several areas for improvement to reduce overutilization, including a national collaborative effort to develop evidence-based appropriateness criteria for imaging; greater use of practice guidelines in requesting and conducting imaging studies; decision support at point of care; education of referring physicians, patients, and the public; accreditation of imaging facilities; management of self-referral and defensive medicine; and payment reform.

Effect of computerized order entry with integrated decision support on the growth of outpatient procedure volumes: seven-year time series analysis.

PURPOSE 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. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSION 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.

Regional chemotherapy of colorectal cancer metastatic to the liver.

Ninety‐three patients with biopsy‐proven colorectal cancer metastatic to the liver were treated with hepatic arterial infusion of 5‐fluorodeoxyuridine (FUDR). There were 52 men and 41 women (median age, 60 years). Forty‐two patients (45%) had failed prior systemic chemotherapy. Catheters were operatively placed and multiple catheters were used if dictated by hepatic arterial anatomy in order to obtain perfusion of the entire liver. The drug was delivered by a totally implanted INFUSAID model 400 pump and patients received cyclic therapy consisting of 2 weeks of 0.3 mg/kg/d FUDR alternating with 2 weeks of saline. Patients with extrahepatic tumor or patients whose hepatic tumor failed to respond to FUDR were given a 30 minute intraarterial infusion of mitomycin C, 15 mg/m2, every 6 to 8 weeks in addition to FUDR. Fifty of the 93 evaluable patients presented with metastatic tumor confined to the liver. Of these 50 patients, 83% demonstrated a significant reduction in tumor size with a median duration of response of 13 months and a median survival of 25 months from diagnosis of liver metastases. Twenty‐four of these 50 patients remain alive. Forty‐three patients presented with extrahepatic metastases in addition to their liver tumor, and 74% had a response with a median duration of 6 months and a median survival of 14 months. Only six patients of those presenting with extrahepatic tumor remain alive. None of the 93 patients died solely of uncontrolled liver tumor, and only 9 died as a result of uncontrolled liver metastases and disseminated extrahepatic tumor. The duration of survival for both groups was determined by the uncontrolled progression of extrahepatic tumor. In patients with metastatic colorectal cancer involving only the liver, hepatic arterial FUDR alone and with the addition of mitomycin C provided excellent control of hepatic tumor. Survival appeared to be prolonged in this uncontrolled study. Cancer 53:1336‐1343, 1984.

Managing Radiation Use in Medical Imaging: A Multifaceted Challenge

This special report aims to inform the medical community about the many challenges involved in managing radiation exposure in a way that maximizes the benefit-risk ratio. The report discusses the state of current knowledge and key questions in regard to sources of medical imaging radiation exposure, radiation risk estimation, dose reduction strategies, and regulatory options.

Solitary Abnormalities in Bone Scans of Patients with Extraosseous Malignancies

The incidence and significance of solitary bone scan abnormalities were assessed in a study of 1,129 consecutive patients with extraskeletal primary malignancies. Solitary abnormalities were encountered in 172 cases (15%). The etiology of the scan abnormality was established in 90 of the 172 cases; 58 (64%) were due to metastatic disease, and 32 (36%) were secondary to a benign process. A significant percentage of solitary scan abnormalities is due to benign disease processes, even in patients with proved extraosseous malignancies.

Early Detection of Stress Fractures Using 99mTc-Polyphosphate

Clinical experience with 99mTc-polyphosphate scintigraphy in more than 200 patients with suspected stress fractures is presented. Stress fractures occur in bone which has been weakened as a result of accelerated physiological change induced by excessive muscular and mechanical activity. Unlike traumatic fractures, they are not accompanied by radiographic abnormality early in their course. Bone scintigraphy is sensitive enough to detect the physiological alterations found in stress fractures and was responsible for decreased morbidity in this series of patients due to early diagnosis.

Radiation Dose Reduction with Hybrid Iterative Reconstruction for Pediatric CT

PURPOSE To assess image quality and radiation dose reduction with hybrid iterative reconstruction of pediatric chest and abdominal computed tomographic (CT) data compared with conventional filtered back projection (FBP). MATERIALS AND METHODS A total of 234 patients (median age, 12 years; age range, 6 weeks to 18 years) underwent chest and abdominal CT in this institutional review board-approved HIPAA-compliant retrospective study. CT was performed with a hybrid adaptive statistical iterative reconstruction (ASIR)-enabled 64-detector row CT scanner. Scanning protocols were adjusted for clinical indication and patient weight to enable acquisition of reduced-dose CT images in all patients, and tube current was further lowered for ASIR protocols. Weight, age, and sex were recorded, and objective noise was measured in the descending thoracic aorta for chest CT and in the liver for abdominal CT. Of the 234 consecutive patients who underwent ASIR-enabled CT (115 chest and 119 abdominal examinations), 70 patients had undergone prior FBP CT. ASIR and FBP CT studies (29 chest and 41 abdominal studies) in these 70 patients were reviewed for image quality, artifacts, and diagnostic confidence by two pediatric radiologists working independently. Data were analyzed with multiple paired t tests. RESULTS Compared with FBP, ASIR enabled dose reduction of 46.4% (3.7 vs 6.9 mGy) for chest CT and 38.2% (5.0 vs 8.1 mGy) for abdominal CT (P < .0001). Both radiologists deemed image quality of and diagnostic confidence with ASIR and FBP CT images as acceptable, without any artifacts. Despite the lower radiation dose used, ASIR images (chest, 10.7 ± 2.5 [mean ± standard deviation]; abdomen, 11.8 ± 3.4) had substantially less objective noise than did FBP images (chest, 13.3 ± 3.8; abdomen, 13.8 ± 5.2) (P = .001, P =.006, respectively). CONCLUSION Use of a hybrid iterative reconstruction technique, such as ASIR, enables substantial radiation dose reduction for pediatric CT when compared with FBP and maintains image quality and diagnostic confidence.

Using imaging biomarkers to accelerate drug development and clinical trials.

There is increasing evidence that human medical imaging can help answer key questions that arise during the drug development process. Imaging modalities such as magnetic resonance imaging, computed tomography and positron emission tomography can offer significant insights into the bioactivity, pharmacokinetics and dosing of drugs, in addition to supporting registration applications. In this review, examples from oncology, neurology, psychiatry, infectious diseases and inflammatory diseases are used to illustrate the role imaging can play. We conclude with some remarks concerning new developments that will be required to significantly advance the field of pharmaco-imaging.

Recommendations for additional imaging in radiology reports: multifactorial analysis of 5.9 million examinations.

PURPOSE To quantify the rates of recommendation for additional imaging (RAI) in a large number of radiology reports of different modalities and to estimate the effects of 11 clinically relevant factors. MATERIALS AND METHODS This HIPAA compliant research was approved by the institutional review board under an expedited protocol for analyzing anonymous aggregated radiology data. All diagnostic imaging examinations (n = 5 948 342) interpreted by radiologists between 1995 and 2008 were studied. A natural language processing technique specifically designed to extract information about any recommendations from radiology report texts was used. The analytic data set included three quantitative variables: the interpreting radiologists experience, the year of study, and patient age. Categoric variables described patient location (inpatient, outpatient, emergency department), whether a resident dictated the case, patient sex, modality, body area studied, ordering service, radiologists specialty division, and whether the examination result was positive. A multivariable logistic regression model was used to determine the effect of each of these factors on likelihood of RAI while holding all others equal. RESULTS Recommendations increased during the 13 years of study, with the unadjusted rate rising from roughly 6% to 12%. After accounting for all other factors, the odds of any one examination resulting in an RAI increased by 2.16 times (95% confidence interval: 2.12, 2.21) from 1995 to 2008. As radiologist experience increased, the odds of an RAI decreased by about 15% per decade. Studies that had positive findings were more likely (odds ratio = 5.03; 95% confidence interval: 4.98, 5.07) to have an RAI. The remaining factors also had significant effects on the tendency for an RAI. CONCLUSION The likelihood of RAI increased by 15% for each decade of radiologist experience and roughly doubled over 13 years of study.

Assessment of Hydroureteronephrosis in Children Using Diuretic Radionuclide Urography

Diuretic radionuclide urography was developed as a safe, accurate and non-invasive method of assessing nephroureteral dilatation to distinguish between obstructive and non-obstructive hydronephrosis. The nuclear medicine gamma camera/computer system is used to monitor the washout pattern of an isotope from any locus of suspected obstruction in the upper urinary tract. This technique was used to study 62 children with hydroureteronephrosis of diverse causes. Our experience suggests that it is accurate in determining whether true obstruction exists in dilated systems and effective in predicting which patients will benefit from corrective operation.