In today’s environment of progressively evolving and expensive imaging modalities, radiologists are asked to justify the use of resources to patients, referring physicians, hospital management, and third party payers. With this aim, the radiologist may use “top-down” or “bottom-up” “evidence-based practice” (EBP) techniques. “Top-down” suggests that the practitioner should wait until a higher authority, external to their practice, generates a solution to practice dilemmas (e.g., National Institute for Health and Clinical Excellence [NICE] guidelines). “Bottom-up” however, is based on the theory that the ordinary practitioner is best served by a decentralized approach to problem solving that is internal to their practice. The technology assessment framework modeled by Mackenzie and Dixon comprehensively assesses the effects of imaging using levels of efficacy including diagnostic performance, diagnostic impact, and therapeutic impact, impact on health and cost effectiveness. In this article, we describe how issues regarding new imaging modalities in ordinary radiology practice can be addressed by using stepwise “bottom-up” EBP techniques combined with the technology assessment framework. We also detail how EBP techniques form an integral part of practice-based learning among radiology residents as part of noninterpretive residency training. The following clinical scenario is used: Your hospital’s chief hepatobiliary surgeon writes to your department regarding the lack of access to 18-fluoro-2-deoxy- d -glucose positron emission tomography in the preoperative assessment of patients with colorectal cancer liver metastases under consideration for hepatic resection. How would you approach this problem? Here is how we would do it.
Clinical scenario
You are an attending radiologist in a busy hepatobiliary tertiary referral centre. The hepatobiliary surgical chairman writes a letter to you concerning the lack of availability of 18-fluoro-2-deoxy- d -glucose positron emission tomography (FDG PET) in the preoperative assessment of patients with colorectal cancer liver metastases (CRCLMs) who are under consideration for hepatic resection. The letter reads as follows:
As you know, the liver is the most frequent site for colorectal cancer metastasis with half of all patients with colorectal cancer developing liver metastases ( ). More than 20% of patients with colorectal cancer have liver metastases at the time of diagnosis, while 40−60% of relapsed patients have CRCLMs ( ). Hepatic resection of CRCLMs is the accepted standard of care and one of the few curative options available to patients.
Accurate preoperative staging is essential in the management of CRCLMs to prevent unnecessary laparotomy in patients who are found to be unresectable at surgery and correctly select those patients with potential for curative resection. FDG PET is a rapidly emerging clinical application in the detection of hepatic and extrahepatic colorectal metastases. Despite this, FDG PET is not available to all our patients being assessed for hepatic resection. It would appear the limited availability and the high cost of FDG PET are restricting its use. I note also in my own research regarding the imaging modality that there is very limited cost-effectiveness data on FDG PET.
I have found on a number of occasions that computed tomography (CT) and magnetic resonance imaging (MRI) have understaged patients on whom I have attempted hepatic resection. This has led to unnecessary surgery, morbidity, and cost. In the environment in which we work where there are limited resources with respect to intensive care unit beds and operating theater time, this is putting a strain on an overburdened service. I believe that FDG PET will stage this patient subgroup more accurately, will impact their management, and may prove to be cost effective.
Recently you used EBP techniques to justify the use of transarterial chemoembolization in the management of hepatocellular carcinoma ( ) ( Fig. 1 ). I would appreciate if you could again use EBP techniques to evaluate the role of FDG PET in the management of patients with CRCLMs.
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Evidence-based practice: The stepwise process
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Step 1: Ask
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Step 2: Search
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Step 3: Appraise
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Table 1
Studies Analyzing the Diagnostic and Therapeutic Impact of FDG PET
Study ⁎ Sample Size Diagnostic Impact Major Management Impact Simo et al [ ] 120 — 48% Kalff et al [ ] 102 — 59% Meta et al [ ] 60 42% 37% Imdahl et al [ ] 71 — 20%
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Step 4: Apply
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Step 5: Evaluate the change in practice
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Technology assessment
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Diagnostic impact
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Therapeutic impact
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Discussion
The Five-Step EBP Process Can Be Used to Devise Department Protocols
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The Technology Assessment Framework Is Useful in Assessing FDG PET
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FDG PET Has a Diagnostic Impact
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FDG PET Has a Therapeutic Impact
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FDG PET Is Effective
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Conclusion
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References
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