Diagnostic Accuracy of Ultrasonography and Computed Tomography in the Diagnosis of Mild-moderate Acute Diverticulitis

Diagnostic Accuracy of Ultrasonography and Computed Tomography in the Diagnosis of Mild-moderate Acute Diverticulitis

Diagnostic Accuracy of Ultrasonography and Computed Tomography in the Diagnosis of Mild-moderate Acute Diverticulitis: Prospective Cohort Study

Acute diverticulitis (AD) is the most common complication of diverticulosis and is divided into mild-moderate and complicated. Imaging methods are needed for its diagnosis, prognostic classification and therapeutic management. Currently the "gold-standard" imaging technique is computed tomography (CT) and most guidelines recommend it to classify and identify those patients with risk of treatment failure. In this styudy, a prospective comparison of CT and abdominal ultrasound is proposed, with the aim of evaluating the diagnostic accuracy of ultrasound. An accurate ultrasound classification of AD would allow the differentiation of mild-moderate and complicated DA, avoiding routine CT and, therefore, patient's x-ray exposure.

Study design, setting and patients. Pragmatic prospective cohort study comparing the diagnostic accuracy of US and CT scan. During a 17-month period patients referred to the imaging department with a clinical suspicion of acute LCD will be evaluated with US and CT. Following the hospital care protocol, patients with suspected uncomplicated LCD will first undergo an abdominal US examination. Immediately after US examination, patients will be evaluated with CT. In emergency cases in which complicated diverticulitis is suspected, the study will start with a CT, followed by ultrasound. The interval between both exploration test will be in all cases less than 1 hour and will be performed before the administration of any anti-inflammatory or antibiotic treatment. US and CT exams will be performed by three different radiologists with blinded results between them. All participating radiologists have more than five years of experience in abdominal radiology. US examinations will be performed with a scanner Aplio 500 (Canon, Tokyo, Japan) employing convex and lineal transducer. CT studies will be performed on 6-MDCT scanner (SOMATOM Emotion Siemens, Germany) following the administration of 120ml of intravenous contrast.

The two imaging examinations will be done by different radiologists blinded for the previous results.

The result of the Abdominal Ultrasonography will be compared with that of the Abdominal Computerized Tomography

The result of the Abdominal Computerized Tomography will be compared with that of the Abdominal Ultrasonography

Identical imaging criteria for the diagnosis of acute diverticulitis will be used used , regardless of the image technique (US or CT). Following the Neff modified classification, the minimum findings to take in to account will bethe presence of diverticula and mural thickening, alone or associated with inflammation of the pericolic fat (Stage 0). Mural thickening will be considered when colonic wall has 4mm or more. Other findings will be: localized pneumoperitoneum depicted by air bubbles (Stage Ia), and abscess < 4cm (Stage Ib). Stage Ia and Ib will be considered as locally complicated diverticulitis. Findings considered as belonging to complicated diverticulitis will be: pelvic abscess > 4cm (Stage II), an intra-abdominal abscess outside the pelvis (Stage III), or difuse pneumoperitoneum and intra-abdominal free liquid (Stage IV).

Identical imaging criteria for the diagnosis of acute diverticulitis will be used used , regardless of the image technique (US or CT).

Number of patients not improving their clinical status during treatment and need a second image evaluation.

Inclusion Criteria: Clinical suspicion of acute diverticulitis Exclusion Criteria: Hemodynamic instability that prevents a diagnostic delay Pregnant patients Previous history of allergy to iodinated contrast