Role of Computed Tomography in Esophageal Varices

Introduction:

The incidence of liver diseases is increasing worldwide. They account for significant morbidity and mortality rates among the general population. There are various kinds of liver diseases, such as those caused by viruses, drugs, or liver cancer. One such chronic liver disease is cirrhosis. Cirrhosis refers to scarring of the tissues resulting in extensive liver damage. Factors such as obesity, excessive alcohol consumption, and chronic hepatitis B and C infection are prime causes of liver cirrhosis. Advanced cirrhosis can be fatal. Esophageal varices and variceal bleeding are the signs of advanced and critical stages of cirrhosis.

What Are Esophageal Varices?

Esophageal varices are engorged and swollen veins of the esophagus (food pipe connecting the mouth to the stomach). Esophageal varices are the most common complication associated with liver cirrhosis. In cirrhosis, the blood flow through the liver is obstructed due to the scar tissues. This results in increased pressure inside one of the major blood vessels of the liver (portal vein). The portal vein takes the blood from the intestine to the liver. An increasing pressure would result in portal hypertension, which would subsequently lead to increased pressure in the veins of the stomach and lower part of the esophagus. The veins in this region are small and are not meant to carry high pressure; hence, they expand and become swollen resulting in esophageal varices. These varices can be stable in size or increase or decrease depending on the improvement of liver disease. However, if the liver disease worsens, these varices can rupture and be life-threatening.

What Are the Types of Esophageal Varices?

What Are the Causes and Risk Factors Associated With Esophageal Varices?

Various conditions associated with esophageal varices are mentioned below:

• Liver Cirrhosis: Cirrhosis is one of the most common causes of esophageal varices.

• Thrombosis: Any blood clot in the portal vein or its feeder’s veins could result in portal hypertension and lead to esophageal varices.

• Schistosomiasis: It is a parasitic infection caused by blood flukes. Blood flukes are freshwater parasite worms that damage the liver and other organs.

All esophageal varices don’t bleed. Risk factors associated with rupture and bleeding of esophageal varices are as given below:

• Portal Hypertension: As portal hypertension increases, the risk of bleeding also increases.

• Larger Varices: Bigger varices are more susceptible to rupture and bleeding.

• Pinpoint Red Marks: Endoscopic examination may reveal certain red marks or streaks along with the varices. These are indicative of high-risk bleeding.

• Liver Failure: Advanced cirrhosis patients may suffer from liver failure. This could also result in bleeding of the varices.

• Excessive Alcohol Consumption: Cirrhotic patients are more prone to variceal bleeding if they continue drinking alcohol.

What Are the Symptoms of Esophageal Varices?

Esophageal varices do not cause signs and symptoms until they rupture and bleed. The symptoms are mentioned below:

• If the bleeding is minor, the patient will have dark or black streaks in their stools.

Severe bleeding will have the following symptoms:

• Vomiting huge quantities of blood.

• Bloody or tarry black stools.

• In severe cases, the patient may faint or become unconscious.

Associated liver disease may have the following additional symptoms:

• Yellowish discoloration of the skin.

• The skin gets easily bruised.

• Ascites (fluid accumulation in the abdomen).

What Are the Complications Associated With Esophageal Varices?

Esophageal varices are the most common complications of liver cirrhosis. Varices do not cause any symptoms until they bleed. However, severe bleeding could result in extensive hemorrhaging and the death of the patient. The risk of repeated bleeding episodes also increases. Early diagnosis and timely treatment can prevent the varices from progressing. Studies have reported that 25 to 40 % of patients experience esophageal bleeding, and the mortality rate from bleeding varices is 15 %. Hence cirrhotic patients must undergo routine screening for prompt diagnosis and management.

What Are the Various Imaging Modalities Used in the Diagnosis of Esophageal Varices?

Various diagnostics tests can detect the presence of esophageal varices; however, the gold standard test is endoscopy. In addition, non-invasive procedures such as CT, ultrasonography, and magnetic resonance imaging (MRI) can also be used to assess the severity of the varices. They are described in detail below:

1. Endoscopy:

Gastrointestinal endoscopy is an invasive procedure used to see the inside of the stomach and the esophagus. A thin, flexible tube with a camera attached to its end is inserted through the mouth into the esophagus and stomach. This camera helps visualize the mucosal lining and other associated gastrointestinal structures from the inside. If varices are noticed, they will be measured and assessed for other risk factors, such as red streaks or wheals, that indicate their risk for rupture and bleeding. The advantage of an endoscopic procedure is to perform a surgical intervention simultaneously if required. However, the major drawback of endoscopy is that it is an invasive procedure requiring intense patient cooperation; if not, the procedure will have to be performed under sedation. It is also an expensive procedure and cannot be used as a routine surveillance tool. In addition, this procedure is not viable for viewing the anatomical structures outside the gastrointestinal tract. Hence external factors contributing to esophageal varices cannot be determined.

2. Plain Radiography:

X-rays are not very specific in diagnosing esophageal varices. However, they can diagnose the varices outside the esophageal wall. They can be seen as abnormal opacities on the x-ray.

3. Barium Study:

Barium study is not very sensitive and should be used if other imaging modalities are contraindicated or cannot be performed. In this test, the patient is asked to swallow a certain amount of thick barium paste, and subsequently, x-ray images are taken. Esophageal varices appear as tortuous filling defects or as thickened folds. However, additional imaging tests need to support these findings as other anomalies may mimic similar findings.

4. MRI:

MRI is a superior choice in diagnosing esophageal varices. It provides high-resolution images and can quantitate (velocity and movement) the portal blood circulation. However, the limited accessibility and high cost restrict its widespread usage in esophageal varices.

5. Ultrasound:

Doppler ultrasound is an excellent tool to assess the movement of blood through the portal veins. It can be used to check for an obstruction in the venous blood flow or narrowing of the vessels. In addition, the endoscopic procedure can be conducted with ultrasound for more precision. However, a conventional ultrasound may not be beneficial in differentiating varices from other conditions causing submucosal masses.

What Is the Role of Computed Tomography in Esophageal Varices?

Prophylactic endoscopy was most commonly used in cirrhotic patients to screen the varices. However, considering the invasiveness, high cost, poor patient acceptance, and the need for sedation, endoscopy was replaced by computed tomography (CT). With the latest advancements, such as multidetector computed tomography (MDCT) and helical CT, patients with chronic liver disease can be routinely screened for disease progression. Contrast CTs have greater sensitivity and specificity in diagnosing esophageal varices. The benefits of CT are:

• Non-invasive.

• Less expensive than endoscopy.

• 90 % sensitivity and 50 % specificity in diagnosing esophageal varices.

• An excellent tool in risk stratification.

• Excellent coverage till the distal part (farther away) of the esophagus.

• The entire abdominal venous system and its associated structures can be seen in CT.

The disadvantages are:

• Allergic reaction to contrast material.

• CT cannot quantitate the blood flow through the portal circulation, which can be done with Doppler ultrasound and MRI.

Routine screening can help with early intervention, reducing the morbidity and mortality associated with variceal rupture.

Conclusion:

Esophageal varices can be a life-threatening condition if not promptly diagnosed and treated. To successfully manage esophageal varices, it is essential to determine the cause. Though endoscopy is the gold standard diagnostic tool, CT has shown far superior results in diagnosing and managing esophageal varices. Advantages such as minimal invasiveness, cost-effectiveness, and increasing compliance make CT a favorable screening tool in patients with chronic liver diseases.