US advantage is availability, no radiation and ability to exclude other causes of pelvic pain, so for me it is better considered as the first line study particularly in thin people.

CT scan can be used in equivocal cases but has the disadvantage of radiation, and its use is limited in children and thin people due to lack of abdominal fat.

US is the first modality of  choice for the diagnosis of acute appendicitis  especially in children 

Ultrasound is the first modality of choice for diagnosing acute appendicitis.

Apart from the positive psoas sign elicited upon graded compression, other features easily seen include increased omental and messenteric fat reflectivity at the right lower quadrant, hyperepestalsis of the surrounding small bowels, and of course the enlarged appendix (>0.6cm) with loss of normal five layer gut wall striation. (the other features aid in an indirect diagnosis should you be grappling with a retrocecal appendix). An overkill in diagnosis is using doppler to demonstrate hyperemia.

Mail clinical Data...  sonography..  no ct..  Appetit..  MRI..  Is verry helpful.

Thank you all ! In your personal experience, what are the sensibility and sensitivity of US for the diagnosis of acute appendicitis ?

Thank you very much indeed.

ultrasound is first choice in children, then MRI.  we usually do MRI for young adults and pregnant patients. we do see some appendicitis in the middle-aged, the diagnosis is usually made by CT as the differential is more broad in this age group and the patients are being seen in the ER, which prefers CT for abdominal pain of uncertain origin.

Ultrasonography is the modality of choice.

Imaging is optional and should come after clinical opinion of the surgeon and biology.

If necessary, US for children, teenagers and pregnant women, CT for adults.

Also at my Institution US is the imaging modality of choiche in children and pregnant women, whereas CT is the one in adults.

In children (< 18 y) we (radiology department with 25 radiologists in a 1000 bed teaching hospital with pediatrics and  pediatric surgery) exclusively use ultrasound. Sensitivity at the first pass is about 85%. With equivocal clinical and radiological findings, a follow up ultrasound on the next day is performed. With this regime, negative appendectomy rate is about 5%, Perforation rate

USG as a first line investigation ...In clinical suspicion with negative USG findings or in cases of complications a CT scan is warranted

Ct of the abdomen and pelvis with contrast (portal phase) for adults and ultrasound for children.  In a pregnant patient, if US is non-diagnostic, will consider MRI. In thin adults may also use US as the initial study.

Ultrasound for pediatrics. CT with only IV contrast or unenhanced of patient is acutely ill with vomiting or significant nausea. If patient can tolerate oral contrast and is subacite or chronic, oral contrast is also administered to ensure bowel imaging is optimal for differential diagnoses... Diverticulitis, panniculitis, ileocaecal TB, bowel lymphoma etc.

In clinically suspected case of appendicitis ultrasonography is the firstline imaging modality. It helps to rule out mimics of appendicitis and identify complications such as pelvic abscess if any had occurred. Classical sonographic signs of acute appendicitis is thickening of appendix wall, fluid collection in its blind lumen and hyperaemia on colour Doppler imaging (CDI). These signs are usually used in combination with clinical signs and symptoms to make a definitive diagnosis.

US is firstly done. If US cannot diagnose, CT is subsequently performed. I begin with non-contrast CT. If acute appendicitis can be diagnosed, no further contrast study is needed.

Ultrasound is the first line of diagnosis in young patients, BMI< 25. In older patients and larger patients, CT is the preferred modality. Ultrasound is less sensitive than CT in diagnosing acute appendicitis. However radiation from Ct abdomen pelvis varies from 10-15 mSv. No radiation risk from ultrasound.