Are Cases of Nonvisualized Appendix on Ultrasound Not Actually Appendicitis? Single-Center Results

Area of Science:

• Radiology
• Emergency Medicine
• Surgical Diagnostics

Background:

• Ultrasonography (USG) is the primary imaging modality for diagnosing acute appendicitis (AA).
• However, USG can fail to visualize the appendix in a significant number of cases.
• This necessitates evaluating alternative diagnostic pathways and imaging strategies.

Purpose of the Study:

• To retrospectively analyze clinical, imaging, and pathology data of patients where the appendix was not visualized on USG.
• To guide clinicians on appropriate next steps in diagnosing acute appendicitis when initial USG is inconclusive.
• To identify factors that can help differentiate between appendicitis and other conditions in these challenging cases.

Main Methods:

• Retrospective analysis of 176 patients (January 2021 - December 2021) with suspected acute appendicitis (AA) where the appendix was not visualized on initial ultrasonography (USG).
• Clinical, imaging (including computed tomography - CT), and pathology results were reviewed.
• Patients were compared based on whether CT was performed and their final diagnosis (AA or other).

Main Results:

• Of 176 patients, 15 (8.5%) were pathologically diagnosed with AA. Two patients discharged without CT were later diagnosed with AA.
• Patients diagnosed with AA had significantly higher white blood cell (WBC) counts (13.4 vs 10.3 × 10^3/mL, p=0.009) and a higher proportion with an Alvarado score ≥ 6 (80% vs 4.3%, p<0.001).
• Computed tomography (CT) was performed in 44.9% of patients, while 55.1% did not undergo CT.

Conclusions:

• In cases where the appendix is not visualized on USG, an absence of leukocytosis (elevated white blood cell count) and an Alvarado score below 6 may indicate a lower probability of acute appendicitis (AA).
• These clinical and laboratory findings can potentially help clinicians avoid further investigations like CT or MRI.
• This approach may optimize resource utilization and reduce patient exposure to radiation.