Are we ready to fight a new turf battle in radiation protection?

Recent studies have raised the problem of dose optimisation imaging protocols in patients with renal colic. Some of them are written by emergency physicians, who seem to pay more attention to this problem than radiologists. We would like to hear what you think about this issue in the comments section below.

Renal colic is a common problem, which is increasing in incidence, affects 10%-15% of people over during their lives, and has a tendency to recur. The ability to rapidly identify kidney stones, as well as their position along the ureter and their dimensions, with high sensitivity and specificity using unenhanced CT, has made this technique the first-line approach to the condition. Since CT involves ionising radiation and there is growing concern about its possible carcinogenic effects, low-dose CT protocols for urolithiasis have been developed to minimise radiation risk.

However, low-dose images and often considered as low-quality images and, although these protocols have been shown to be accurate for stone detection, there are concerns about their use due to fears of missing other diagnoses that may clinically mimic stone disease, such as appendicitis, diverticulitis, and cholecystitis. A possible solution could be to use different CT protocols according to the pre-test probability of stone disease. In patients with a previous history of urolithiasis, a low-dose CT examination would be sufficient.

Some recent papers (1, 5) underline the importance of diagnostic protocols that take into account radiation protection issues in these patients. The first one shows that reduced-dose renal protocol CT is used infrequently in the USA and that mean dose index is higher than reported previously and institutional variation is substantial (1). A comment to this paper (2) underlines the need for continued education as well as commitment to understanding and implementing best practices for the use of ionizing radiation in medical imaging

Two other papers go even further. Patatas and co-workers (3) reviewed 1,357 consecutive cases of suspected renal colic examined with CT at their emergency radiology practice. They found a significant percentage of negative studies in female patients and suggest the use of ultrasound (US) as a first-line investigation in female cases, to avoid unnecessary radiation. Dalziel and Noble (4), after underlining the concerns over CT-related radiation exposure, present a literature review comparing the results of US and CT for patients with flank pain and suggest a diagnostic algorithm in which US is used first and subsequent management is driven by its results.

Finally, the results of a multicenter, comparative effectiveness trial on 2759 patients published by Smith-Bindman et al. in the New England Journal of Medicine showed that diagnostic work-up based on clinical findings and US allowed lower cumulative radiation exposure than initial CT, without significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits or hospitalizations (5).

All these papers raise the question of whether CT scans are always required or are the best test in the initial assessment of flank pain. US is more difficult and time consuming to perform than unenhanced CT. It is operator-dependent, needs manual dexterity and a lot of experience but can provide a safe and effective approach to these patients (6). Are we ready to use US to examine all patients coming in with suspected renal colic?

The most important aspect in this post is the news that Dalziel and Noble, as well as many of the co-authors of Smith-Bindman, are not radiologists. They are emergency physicians. Are we ready to fight turf battles in radiation protection as well? Comment below and let us know what you think.

Prof. Lorenzo Derchi is Chair of the Radiology Department of the Hospital of the University of Genoa and the ESR Publications Committee.

1) Lukasiewicz A, et al. (2014) Radiation dose index of renal colic protocol CT studies in the United States: a report from the American College of Radiology National Data Registry Radiology 271:445-451
2) Brink JA. (2014) Radiation dose index in renal colic protocol CT: are we doing enough to ensure adoption of best practices? Radiology 271:323-325
3) Patatas K, et al. (2012) Emergency department imaging protocol for suspected acute renal colic: re-evaluating our service Brit J Radiol 85:1118-1122
4) Dalziel PJ, Noble VE. (2013) Bedside ultrasound and the assessment of renal colic: a review Emerg Med J 30:3-8; Smith-Bindman R et al (2014) Ultrasonography versus computed tomography for suspected nephrolithiasis N Engl J Med 371:1100-1110; Nicolau C, et al. (2015) Imaging patients with renal colic—consider ultrasound first Insights Imaging 6:441-447

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    7 Responses to : Are we ready to fight a new turf battle in radiation protection?

    1. Jan Bauer says:

      Dear Professor Derchi,
      I am shocked that you call it a battle if other physicians publish on radiation protection issues. I am very happy that emergency physicians finally have realized this problem as well. I think we cannot solve this problem alone, but only in an interdisciplinary effort – we as radiologists know few about an a priori probability of urolithiasis, to give one example. It is true that radiologists will have to care about radiation protection more than they do now. But practically, this only will work in an environment, where the referring physician also knows the problem and does not request a whole body CT with optimal image quality regardless the clinical question. We have to solve this with each other, not against each other.

    2. Tim Leiner says:

      The referring clinicians raise important points that we as radiologists can use to improve the way we deliver our imaging services. Coming to an agreement 1) on who needs to be imaged and 2) a low-dose protocol across vendors and systems is a first step to standardize delivery of care in a best-practice way. Also, we need to better educate our referrers with regard to the availability of new technology to reduce dose such as dual energy and spectral CT. And, it may well be possible that in some centers CT works better, whereas in others US may work. Differences in case-mix and local experience are all factors that need to be considered. As radiologists we have to actively think about these issues and devise our own strategies before others decide for us how to deal the (perceived) problem of high dose imaging.

    3. APP says:

      I am glad for any professional who cares about radiation doses. If physicians pick up the ultrasound probe and get their patients fast and radiation free diagnoses, I am relieved. The work load for radiologists will not decline, it will just change. We will probably lose some fields which are “cheaper” and “portable” to other physicians, but we will keep getting more complicated CT and MRI exams. As a thoracic radiologists I am preparing for MRI thorax to develop into a regular exams within the next decade. We should be ready for the shift and not consider this a turf battle.
      We should also remember that we previously have gained fields from other medical specialists. One orthopedic surgeon was recently telling me that when he started training they young doctors started with diagnostic arthroscopy, nowadays the arthroscopy is mostly surgery, and the younger doctors have “lost” their easy procedure, which used to be their stepping stone to more complicated surgery. MRI diagnosis so much now!
      We will have to accept shifts, and any shift which does not lead to worsened treatment of patients should be accepted as good competition.
      Yes, US is operator dependant etc, but if emergency room US spares radiation dose to patients, how can any radiologist argue with that?
      Another side of this discussion is also the accessibilty of any examination. If the US is fully booked and there is no radiologist or physician to perform the examination, while the CT is empty, I know that some clinicians will say, well- we need to send the patient home if there is no pathology, just get it done fast!
      There is no final solution, but I suspect each hospital/radiology department has to follow the needs of the clinician as best it can with the least radiation exposure to patients.

    4. Alberto Tagliafico says:

      Dear Collegues,
      in the upcoming era of “personalized medicine” we have not to forgot that clinical evaluation of patients is crucial before asking for an imaging study. A good clinical evaluation enhances the pre-test probability of every diagnostic study. I’m so happy that clinicians care about radiation dose as well as I (and some of my collegues) care about a comprehensive clinical examination to drive the clinical suspect. The burden of radiations will be reduced also if the clinician performs a careful clinical examination (this is not always the case, if I write this…). In a more personalized enviroment, I believe that the use of US or CT should depend on clinical history (age, previous pathology, risk factors..), laboratory tests, epidemiology, etc. So the use of CT or US should depend mainly on the pre-test probability of confirming the clinical suspect. I suppose this is true mainly for US. The use of CT should be carefully tailored.
      Finally, I’m glad to discuss with colleagues who are not radiologists. However, in the Emergency Dept I think that it should be better to explain the reason of the pain, not only to exclude the major diagnosis. This approach could reduce, for the same patients, another admission in the Emergency Dept for the same reason of the first time.
      Nice topic, for me.

    5. Marc-André Weber says:

      Dear colleagues,
      I agree with Alberto Tagliafico that the use of ultrasound or computed-tomography should depend on several factors such as clinical history and pre-test probability of stone disease. One of our goals should be to well teach our residents in renal ultrasonography so that they reliably diagnose stone disease in case of renal colic. Another goal is to continue reducing the radiation exposure of our CT protocols and to adapt these to the individual patient. Also, I am very happy that our clinical partners have an increasing awareness of radiation protection and radiation exposure of CT examinations. Here, radiologists together with medical physicists should continue to play the key role. Many activities of the ESR are already focussing on these issues.
      With best wishes,
      Marc-André Weber

    6. Marion Smits says:

      I fully agree with the shocked response above… how can we feel threatened by colleagues joining our efforts to reduce radiation?! I really don’t think the most important aspect is the fact that it is non-radiologists who raise the issue: the issue of high-radiation, potentially poorly indicated CT scans is much more important…

    7. Emerald says:

      In radiation protection as in all other fields to defend ourselves against (man made) environmental threats, we all have to cooperate in order to survive as human species.