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• Re:Inaccurate radiation exposure calculation
  William D. Rogers
  Published on: 25 September 2015
• Inaccurate radiation exposure calculation
  Nigel D'Souza
  Published on: 3 August 2015
• Re:Further research in low dose CT scan for suspected appendicitis.
  William D Rogers
  Published on: 2 March 2015
• Further research in low dose CT scan for suspected appendicitis.
  Dr. Paul V Puthussery
  Published on: 2 March 2015

• Published on: 25 September 2015

  Re:Inaccurate radiation exposure calculation

  • William D. Rogers, Assistant Clinical Professor

  Dear Editor,

  You are correct that protocols and improved technology have led to reductions in radiation exposure from CT scanning at some hospitals. I would suggest though that the resultant reduction in the risk of fatal cancer due to imaging does not affect the conclsion of the paper. If a laparotomy on a healthy young patient carries no risk of death and CT scanning imposes a risk of death the decision to perfor...

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  Dear Editor,

  You are correct that protocols and improved technology have led to reductions in radiation exposure from CT scanning at some hospitals. I would suggest though that the resultant reduction in the risk of fatal cancer due to imaging does not affect the conclsion of the paper. If a laparotomy on a healthy young patient carries no risk of death and CT scanning imposes a risk of death the decision to perform a CT scan on a young healthy person before proceeding to the operating room poses an ethical dilemma for the ordering physican.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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• Published on: 3 August 2015

  Inaccurate radiation exposure calculation

  • Nigel D'Souza, Trainee General Surgeon

  Dear Editor,

  Dr Rogers et al have astutely pointed out the dangers of routine CT assessment of right iliac fossa pain in the paediatric population. I agree wholeheartedly that the role of clinical judgement, alongside observation and serial examination remain critical. Ultrasonography and MRI are additional valuable diagnostic adjuncts that do not incur a radiation dose to patients.

  I would question the da...

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  Dear Editor,

  Dr Rogers et al have astutely pointed out the dangers of routine CT assessment of right iliac fossa pain in the paediatric population. I agree wholeheartedly that the role of clinical judgement, alongside observation and serial examination remain critical. Ultrasonography and MRI are additional valuable diagnostic adjuncts that do not incur a radiation dose to patients.

  I would question the data the authors have used to calculate the risk of CT induced cancer. The estimates from the BEIR V data are based on a radiation exposure of 10mSv. Contemporary CT-appendix protocols expose patients to around 2mSv or less, but have equivalent accuracy to a CT scan of the abdomen and pelvis. Would it not be more appropriate to calculate the risk of cancer based on these figures?

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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• Published on: 2 March 2015

  Re:Further research in low dose CT scan for suspected appendicitis.

  • William D Rogers, Assistant Clinical Professor

  We share your enthusiasm for the current efforts to reduce radiation exposure associated with the use of CT scanning and agree with your assertion that performance of appendectomy without scanning will inevitably lead to more negative appendectomies. We are confident though based on the NHS laparoscopic appendectomy statistics reviewed by Omar and Clark in the Annals of Surgery that those negative appendectomies are asso...

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  We share your enthusiasm for the current efforts to reduce radiation exposure associated with the use of CT scanning and agree with your assertion that performance of appendectomy without scanning will inevitably lead to more negative appendectomies. We are confident though based on the NHS laparoscopic appendectomy statistics reviewed by Omar and Clark in the Annals of Surgery that those negative appendectomies are associated with essentially no risk. In the NHS series 234,402 patients underwent laparoscopic appendectoy without a single death or major morbidity. CT scanning these 234 thousand patients on the other hand will cause more than 100 fatal cases of cancer.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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• Published on: 2 March 2015

  Further research in low dose CT scan for suspected appendicitis.

  • Dr. Paul V Puthussery, Assistant Professor in Radiodiagnosis
  • Other Contributors:
    • Dr Sandhya George

  Dear Editor,

  We read with great interest the recent article written by William Rogers et al on the Harms of CT scanning prior to surgery for suspected appendicitis(1). It highlights the radiation risk of cancer while routinely performing an abdominal CT scan on an otherwise healthy patient with symptoms suggestive of appendicitis. This radiation risk of cancer becomes all the more important in patients with 'ne...

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  Dear Editor,

  We read with great interest the recent article written by William Rogers et al on the Harms of CT scanning prior to surgery for suspected appendicitis(1). It highlights the radiation risk of cancer while routinely performing an abdominal CT scan on an otherwise healthy patient with symptoms suggestive of appendicitis. This radiation risk of cancer becomes all the more important in patients with 'negative' appendectomy.

  However, relying purely on clinical judgment for diagnosis of appendicitis can result either in increased 'negative' appendectomy or diagnostic delay which may cause appendiceal perforation. There are studies which show that negative appendectomy is associated with an appreciable degree of morbidity and mortality, including a significant increase in length of hospital stay, postoperative complications like wound infection and death(2). Also, it can increase health care costs. Perforated appendicitis is also related to increase in length of hospital stay(3). In-house mortality is high for perforated appendicitis(4).

  During the last decade, there have been many advances in CT technology which have resulted in improved spatial resolution, rapid scan and increased use of multiplanar images enabling better visualization of appendix. Although the effective dose value for CT scan of abdomen and pelvis is taken as 8 - 11 mSv(5) , studies comparing low-dose CT group with standard-dose CT group have shown that low-dose CT was not inferior with regard to diagnosis of appendicitis(6) and negative appendectomy rates(7) . Neither the appendiceal perforation rate nor the diagnostic performance of CT for appendicitis differed significantly between the two groups. A randomized controlled trial, low-dose CT for appendicitis trial (LOCAT) is being undergone comparing the clinical outcomes following low vs standard-dose computed tomography as the first-line imaging test in adolescents and young adults with suspected acute appendicitis, where the effective dose of CT is reduced to 2 mSv(8). This greatly reduces the carcinogenic risk. Study using non-contrast focused abdominal CT scan has also shown to have a high sensitivity for diagnosis of appendicitis(9). Here, there is no risk of contrast nephropathy.

  Further research in this field will enable us to use very low dose CT scan with significantly less radiation risk of cancer; at the same time significantly reducing negative appendectomy rate without an increase in the appendiceal perforation rate.

  References

  (1) Rogers, W., Hoffman, J., Noori, N. Harms of CT scanning prior to surgery for suspected appendicitis. Evidence Based Medicine 2015;20(1):3-4.

  (2) Flum DR, Koepsell T. The clinical and economic correlates of misdiagnosed appendicitis: nationwide analysis. Arch Surg 2002;137:799-804.

  (3) Al-Omran M, Mamdani M, McLeod RS. Epidemiologic features of acute appendicitis in Ontario, Canada. Can J Surg 2003;46:263-268.

  (4) Wen SW, Naylor CD. Diagnostic accuracy and short-term surgical outcomes in cases of suspected acute appendicitis. CMAJ 1995;152:1617-1626.

  (5) Furlow B. Radiation dose in computed tomography. Radiol Technol 2010;81:437-50.

  (6) Keyzer, C., Tack, D., De Maertelaer, V., et al. Acute Appendicitis: Comparison of Low- Dose and Standard-Dose Unenhanced Multi-Detector Row CT 1. Radiology 2004;232(1):164-172.

  (7) Kim, K., Kim, Y. H., Kim, S. Y., et al. (2012). Low-dose abdominal CT for evaluating suspected appendicitis. New England Journal of Medicine 2012;366(17):1596-1605.

  (8) Ahn S. LOCAT (low-dose computed tomography for appendicitis trial) comparing clinical outcomes following low- vs standard-dose computed tomography as the first-line imaging test in adolescents and young adults with suspected acute appendicitis: study protocol for a randomized controlled trial.Trials. 2014;15:28. doi:10.1186/1745-6215-15-28.

  (9) Akhtar, W., Ali, S., Arshad, M., Ali, F., Nadeem, N. (2011). Focused abdominal CT scan for acute appendicitis in children: can it help in need. Journal of the Pakistan Medical Association 2011; 61(5):474-6.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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