Correlation between Alvarado Score and Measurement of Appendiceal Wall Thickness and Intraluminal Lumen Thickness on CT in the Diagnosis of Acute Appendicitis

Every year, millions of people around the world face a sudden, sharp pain in the lower right side of their abdomen. For doctors, this is often a signal of acute appendicitis, an inflammation of the small, finger-like pouch attached to the large intestine. It is the most common reason for emergency abdominal surgery, and getting the diagnosis right is a matter of urgency. If the condition is missed, the appendix can burst, leading to a dangerous infection of the abdominal cavity. However, the symptoms can be tricky; they sometimes mimic other illnesses, especially in young children, women of childbearing age, and older adults. To help sort through this confusion, physicians have long relied on a clinical checklist known as the Alvarado score. This system assigns points based on what a patient feels and what simple blood tests show, such as whether they have a fever, a loss of appetite, or an elevated white blood cell count. A high score suggests a high likelihood of appendicitis, while a low score suggests it is unlikely.

In recent decades, the medical community has increasingly turned to computed tomography, or CT scans, to look inside the body and confirm the diagnosis. A CT scan creates detailed cross-sectional images, allowing doctors to see the appendix and the surrounding tissues clearly. The standard way to interpret these images has been to measure the width of the appendix. If the outer edge-to-edge width is larger than a specific threshold, it is usually considered inflamed. Yet, this method is not perfect. Sometimes the appendix looks borderline, measuring just slightly above or below the cutoff, leaving doctors uncertain about whether to operate. This uncertainty can lead to unnecessary surgeries or, conversely, missed diagnoses. Researchers at Zagazig University and Galala University set out to refine this process. They wanted to see if looking at different parts of the appendix on a CT scan—specifically the thickness of the wall and the size of the inner channel—could provide a clearer picture than the outer width alone, and how these measurements might align with the traditional clinical scoring system.

The team reviewed the medical records of 71 patients who had been suspected of having appendicitis and had undergone a contrast-enhanced CT scan between January 2024 and January 2026. Contrast-enhanced means a special dye was injected into the patients' veins to make the blood vessels and tissues stand out more clearly on the images. Two experienced radiologists, who did not know the patients' final outcomes, independently examined the scans. They measured three specific things: the total width of the appendix from outer wall to outer wall, the thickness of the appendix wall itself, and the width of the fluid-filled space inside the appendix, known as the lumen. They also noted other signs, such as whether the fat surrounding the appendix looked streaky or inflamed. After gathering these measurements, the researchers compared them against the final truth: whether the patient actually had appendicitis, confirmed either by surgery or by a clear resolution of symptoms with antibiotics.

The results painted a detailed picture of what a healthy appendix looks like versus an inflamed one. In the 63 patients who were confirmed to have appendicitis, the fat surrounding the organ was always streaky and inflamed, a sign that was present in every single positive case and absent in every negative case. When the researchers looked at the measurements, they found that the inflamed appendices were significantly wider, had thicker walls, and contained a much larger volume of fluid inside compared to the healthy ones. The average outer width of the inflamed appendix was nearly 10 millimeters, while the healthy ones measured just 6 millimeters. The wall thickness in inflamed cases averaged 2.3 millimeters, compared to 1.1 millimeters in healthy cases. Most notably, the inner channel, or lumen, was much more distended in the sick patients, averaging 5.2 millimeters wide, whereas the healthy lumen was only about 1.8 millimeters.

To determine which of these measurements was the most reliable for making a diagnosis, the researchers used a statistical method that identifies the best point to separate a sick patient from a healthy one. They found that while the traditional outer width measurement was highly specific, the thickness of the inner fluid column achieved the highest overall accuracy score (AUC) for distinguishing between the two groups. A cutoff of 2.21 millimeters for the inner lumen thickness correctly identified the vast majority of appendicitis cases, offering higher sensitivity than the conventional outer-diameter criterion, though with slightly lower specificity. The wall thickness was also a strong indicator, but the inner lumen size proved to be the single best metric in terms of overall diagnostic performance. The study also looked at how these findings matched up with the Alvarado score. They found that patients with intermediate or high scores on the clinical checklist almost always had CT scans that confirmed appendicitis, with confirmation rates exceeding 93 percent. This suggests that when a patient's symptoms and blood work point toward the disease, the CT scan almost invariably confirms it.

The researchers concluded that looking at the inner fluid column of the appendix on a CT scan offers a more sensitive way to diagnose acute appendicitis than relying solely on the outer width. By combining these precise measurements with the clinical Alvarado score, doctors can create a more robust framework for decision-making. This approach helps to clarify those borderline cases where the diagnosis is not immediately obvious, potentially reducing the number of unnecessary surgeries while ensuring that those who need treatment receive it quickly. The study did not claim to have solved the problem of appendicitis diagnosis entirely, but it provided concrete evidence that refining how we measure the organ can lead to better, more accurate outcomes for patients.