The Optimization of a Low-dose CT Protocol in Patients With Suspected Uncomplicated Acute Appendicitis and BMI >30
The Optimization of a Low-dose CT Protocol in Patients With Suspected Uncomplicated Acute Appendicitis and BMI >30
This study focuses on the use of contrast enhanced low-dose CT imaging as a modality to
 differentiate between uncomplicated and complicated acute appendicitis. Accurate differential
 diagnosis allows the assessment of all available treatment options. Complicated acute
 appendicitis requires emergency appendectomy, while uncomplicated acute appendicitis can be
 safely and efficiently treated with antibiotics in the majority of patients. Our study group
 already published the results of the initial OPTICAP trial enrolling patients with BMI under
 30 showing similar accuracy between the low-dose and the stadard dose CT, but a significant
 dose reduction associated with the low-dose CT. All patients will undergo both imaging
 protocols as the standard CT is also optimized for a low as possible radiation dosage and
 imaging sequence per patient is randomized due to the optimization of contrast media
 injection timing. All patients participating in this study will be treated operatively with a
 laparoscopic appendectomy to obtain histological confirmation for the diagnosis to evaluate
 the accuracy of the CT imaging. The aim of this study is to optimize a well-performing
 low-dose CT imaging protocol to use in the diagnosis of uncomplicated acute appendicitis in
 patients with body mass index over 30 kg/m2.
Acute appendicitis is one of the most common causes of abdominal pain in emergency
 departments as well as one of the most common indications for emergency abdominal surgery.
 The clinical diagnosis has been based on patient history, physical examination and laboratory
 findings as well as the "clinical eye" of the surgeon. Still the diagnosis remains
 challenging. One of the main problems is that many other disorders can mimic the clinical
 presentation of appendicitis, thus increasing the role of imaging techniques to aid in
 diagnostic accuracy. Now preoperative imaging in patients with suspected acute appendicitis
 is currently widely accepted as the gold standard and CT has been shown to clearly outperform
 US in terms of diagnostic performance. Currently CT imaging is considered the primary imaging
 modality in the diagnosis for acute appendicitis as it is appraised for its high sensitivity
 and specificity. The main disadvantage of CT imaging is exposure to radiation. Thus the
 favorable diagnostic performance of CT imaging has encouraged optimization of protocols to
 minimize exposure to radiation through the development of low-dose CT protocols. Initial
 studies have indicated that contrast enhanced low-dose CT was not inferior to standard-dose
 contrast enhanced CT with no statistical significance in negative appendectomy rates,
 appendiceal perforation rates or patients requiring additional imaging.

 This study focuses on the use of contrast enhanced low-dose CT imaging as a modality to
 differentiate between uncomplicated and complicated acute appendicitis in patients with BMI
 over 30 kg/m2. Accurate differential diagnosis allows the assessment of all available
 treatment options. Complicated acute appendicitis requires emergency appendectomy, while
 uncomplicated acute appendicitis can be safely and efficiently treated with antibiotics in
 the majority of patients. Our study group already published the results of the initial
 OPTICAP trial enrolling patients with BMI under 30 showing similar accuracy between the
 low-dose and the stadard dose CT, but a significant dose reduction associated with the
 low-dose CT. All patients will undergo both imaging protocols as the standard CT is also
 optimized for a low as possible radiation dosage and imaging sequence per patient is
 randomized due to the optimization of contrast media injection timing. All patients
 participating in this study will be treated operatively with a laparoscopic appendectomy to
 obtain histological confirmation for the diagnosis to evaluate the accuracy of the CT
 imaging. The aim of this study is to optimize a well-performing low-dose CT imaging protocol
 to use in the diagnosis of uncomplicated acute appendicitis in patients with body mass index
 over 30 kg/m2.
Inclusion Criteria:

 -  Age 18-60 years

 -  Clinical suspicion of acute uncomplicated appendicitis based on history, physical
 examination, laboratory findings evaluated by a senior surgeon

 -  Body mass index over 30 kg/m2

 Exclusion Criteria:

 -  Age <18 years or > 60 years

 -  Pregnancy or breastfeeding

 -  Allergy to contrast material or iodine

 -  History of appendectomy

 -  Renal failure, creatinine-value greater than the upper reference value

 -  Diabetes mellitus and metformin medication

 -  Suspicion of peritonitis and appendiceal perforation

 -  Incapability to cooperate and give consent to participate in the study