Background Contrast-enhanced CT is the reference standard used in the imaging diagnosis of acute appendicitis in adults. The radiation dose has been a cause of concern. This study aimed to evaluate whether a lower radiation dose would affect the diagnostic accuracy of CT. Methods This was a single-center prospective cohort study of patients (over 16 years) with suspected appendicitis evaluated for enrollment in concurrent APPAC II-III trials. The diagnostic accuracy of low-dose and standard contrast-enhanced CT was compared with study protocols guiding BMI-based imaging; this allowed direct comparison of CT images only in patients with a BMI below 30 kg/m2. The on-call CT diagnosis was compared with the final clinical diagnosis. Results Among the 856 patients investigated, the accuracy of low-dose (454 patients) and standard-dose (402 patients) CT in identifying patients with and without appendicitis was 98.0 and 98.5 percent, respectively. In patients with a BMI below 30 kg/m2, the respective values were 98·2 percent (434 patients) and 98·6 percent (210 patients) (P = 1·000). The corresponding accuracy in differentiating between complicated and uncomplicated acute appendicitis was 90.3 and 87.6 percent in all patients, and 89.8 and 88.4 percent respectively among those with a BMI below 30 kg. / m2 (P = 0 663). The mean radiation dose in all low-dose and standard-dose CT groups was 3 and 7 mSv, respectively. In the group with a BMI below 30 kg/m2, the corresponding mean doses were 3 and 5 mSv (P < 0.001). Conclusion Low-dose and standard-dose CT were accurate both in identifying appendicitis and in differentiating between complicated and uncomplicated acute appendicitis. Low-dose CT was associated with a significant reduction in radiation dose, suggesting that it should be standard clinical practice at least in patients with a BMI below 30 kg/m2. |
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Doctors can use CT scans with less radiation to diagnose appendicitis
A new article in the British Journal of Surgery , published by Oxford University Press, indicates that it is now possible to diagnose appendicitis using low-dose CT scans, reducing radiation exposure, which is of great clinical importance, especially in patients youths.
Appendicitis is one of the most common causes of hospital admissions and appendectomies are some of the most common surgical procedures performed worldwide. However, appendicitis can be difficult to diagnose. Such difficulties can delay or lead to unnecessary surgeries. Contrast-enhanced computed tomography (CT) scans are very useful in helping doctors make the correct diagnosis, but there are concerns about radiation exposure.
Increasing evidence on the safety and effectiveness of nonsurgical treatment for uncomplicated acute appendicitis has placed new demands on the accuracy of diagnoses in both acute appendicitis and the severity of appendicitis. As emergency appendectomy is no longer considered the only treatment alternative for patients with uncomplicated acute appendicitis, the emphasis has shifted from solely evaluating whether a patient has appendicitis or not to differentiating between complicated and uncomplicated acute appendicitis.
Imaging has become standard in the diagnosis of appendicitis, reducing both the negative appendectomy rate and overall treatment costs.
Although ultrasound is often used in the pediatric population to avoid the dangers of radiation, a CT scan is the most accurate way to diagnose appendicitis in adults.
The researchers here studied patients treated between April 4, 2017 and November 27, 2018 at Turku University Hospital, Finland. The hospital admitted a total of 989 patients to the emergency room with suspected acute appendicitis. About 53% underwent low-dose CT scans and 47% were diagnosed with standard-dose CT scans.
The researchers found that the overall accuracy of low-dose and standard-dose CT scans in identifying patients with and without acute appendicitis was 98% and 98.5%, respectively. The accuracy in differentiating between complicated and uncomplicated acute appendicitis using the different types of CT scans was 90.3% and 87.6%, respectively.
This study shows that low-dose and standard-dose CT scans were accurate both in identifying appendicitis and in differentiating between severe cases requiring surgery and those that can be treated with antibiotics alone.
"The results of this study suggest that the radiation dose of diagnostic CT scanning can be significantly reduced without affecting the accuracy of the diagnosis," said the paper’s lead author, Paulina Salminen. "These findings will hopefully encourage clinicians to implement low-dose CT modalities in emergency departments for imaging acute appendicitis to avoid unnecessary radiation in this large patient population."
