Computed Tomography Versus Ultrasound for the Diagnosis of Acute Cholecystitis
Author(s):
Eva Fuentes, Massachusetts General Hospital; Peter Fagenholz, Massachusetts General Hospital; Haytham Kaafarani, Massachusetts General Hospital ; Catrina Cropano; David King, Massachusetts General Hospital; Marc De Moya, Massachusetts General Hospital ; Kathryn Butler, Massachusetts General Hospital ; George Velmahos, Massachusetts General Hospital ; Daniel Yeh, MD, Massachusetts General Hospital
Background: Ultrasound (US) is the first line diagnostic study for evaluating gallstone disease and is considered the test of choice for diagnosing acute cholecystitis (AC). However, computed tomography (CT) is widely used for the evaluation of abdominal pain and is often obtained as a first abdominal imaging test, particularly in cases in which typical clinical signs of AC are absent, or other possible diagnoses are being considered.
Hypothesis: We hypothesized that CT is more sensitive than US for diagnosing AC, and that if CT shows AC, a US is not needed to confirm the diagnosis.
Methods: A prospective registry of all urgent cholecystectomies performed by our Acute Care Surgery service between June 2010 and January 2014 was queried for cases of AC. Patients were classified into two groups according to pre-operative radiographic work-up: US only, or CT and US. The final diagnosis was based on operative findings and pathology.
Results: A total of 209 patients underwent cholecystectomy for AC. All patients underwent US and 57 (27%) also underwent CT. In the subgroup undergoing both CT and US the sensitivity of US was 82% (47/57) compared to 93% for CT (53/57) (p=0.15). US and CT agreed on the diagnosis of AC in 45 cases (79%). In the remaining 12 patients, the diagnosis of AC was missed by US in 8 patients (14%), missed by CT in 2 patients (3%), and missed by both in 2 patients (3%). Patients undergoing US and CT were more likely to be male, older, have medical comorbidities, were less likely to have typical signs and symptoms of AC, and more likely to have systemic manifestations such as fever and leukocytosis (Table 1).
|
US only
152
|
CT and US
57
|
P
|
Age (Median, years)
|
38.5
|
57
|
<.0001
|
Male
|
31
|
53
|
.004
|
Comorbidities
|
|
|
|
Diabetes %
|
7
|
21
|
.004
|
Hypertension %
|
18
|
49
|
<.0001
|
Hyperlipidemia %
|
11
|
33
|
<.0001
|
Clinical Signs/Symptoms
|
|
|
|
Nausea or vomiting %
|
81
|
65
|
.034
|
Murphy’s Sign %
|
64
|
44
|
.018
|
WBC >11 K
|
52
|
68
|
.033
|
Fever %
|
11
|
26
|
.004
|
Conclusions: CT often diagnoses AC in patients with atypical clinical signs, and US is not needed to confirm the diagnosis. CT may be more sensitive than US for the diagnosis of AC, though this requires further investigation in larger studies.