Sigmoid diverticulitis: US findings

Abstract

Acute diverticulitis (AD) results from inflammation of a colonic diverticulum. It is the most common cause of acute left lower-quadrant pain in adults and represents a common reason for acute hospitalization, as it affects over half of the population over 65 years with a prevalence that increases with age. Although 85% of colonic diverticulitis will recover with a nonoperative treatment, some patients may have complications such as abscesses, fistulas, obstruction, and /or perforation at presentation. For these reasons, different classifications were introduced through times to help clinicians to develop a correct diagnosis and guide the treatment and for the same reasons imaging is used in most cases both to realise a differential diagnosis and to guide the therapeutic management. US and CT are both usefull in diagnosis of diverticolitis, and their sensibility and specificity are similar. However CT scanning is essential for investigating complicated diverticular disease especially where there are diffuse signs and clinical suspicion of secondary peritonitis; instead in most uncomplicated cases the experienced sonographer may quickly confirm a diagnosis guided by the clinical signs. US is to be recommended in premenopausal women, and in young people to reduce dose exposure.

Benefits of Sonography in Diagnosing Suspected Uncomplicated Acute Diverticulitis

“…In anticipating potentially life-threatening complications of acute diverticulitis (eg, peritonitis, perforation, intra-abdominal abscesses, fistulas, and obstructions), CT has become the diagnostic modality of choice in most of the western world. 3,7,14,19,20 In cases in which abscesses are detected, CT can further guide percutaneous drainage and provide an indication for embolization of diverticular bleeding. However, CT is not readily available in emerging and underdeveloped nations, 21 requires increased time for interpretation by a radiologist, exposes the patient to ionizing radiation, and, unlike sonography, is not cost-effective.…”

“…In the largest meta-analysis of its type, approximately 630 patients (across 6 studies) were evaluated with sonography, and 684 patients (across 8 studies) were evaluated with CT; both yielded similar accuracy, with 92% and 94% summary sensitivity and 90% and 99% summary specificity, respectively. [5][6][7][8] Additionally, Laméris et al 9 identified several clinical and laboratory parameters aimed toward accurately diagnosing mild diverticulitis, which when positive obviated the need to perform CT, including localized left lower quadrant tenderness, absence of vomiting, and elevated Creactive protein levels. 10 However, when uncomplicated acute diverticulitis was clinically suspected but not all 3 of these criteria were met, the results were more variable.…”

“…However, in the clinical settings of suspected mild and uncomplicated diverticulitis (stages 0 and 1a), unnecessary radiation exposure, lengthy turnaround times in overcrowded emergency departments (EDs), and increased cost to the current financially burdened system are practical concerns associated with CT, which lend consideration to a nuanced diagnostic approach that should be less reliant on this imaging modality. 15,16 Given the nearly equivalent sensitivity and specificity of sonography and CT for identifying stages 0 and 1a, [5][6][7][8][9] we investigated the radiation dose and turnaround time savings associated with the use of bedside sonography over CT in a selected subset of patients with clinical signs and symptoms of suspected uncomplicated acute diverticulitis (stages 0 and 1a).…”

Errors in imaging the pregnant patient with acute abdomen

“…This condition is mostly caused by adhesions (60-70%) and volvulus (25%) [12], but other conditions can predispose, i.e., intussusception (<5%), colorectal carcinoma (3.7%), hernia (1.4%), appendicitis (0.5%), and diverticulitis (0.3%) [31][32][33]. Adhesions are more frequently seen in later stages of pregnancy with increasing rates from the first to the third trimester (6 vs. 45%) [31,32].…”

Role of ultrasound in colorectal diseases

“…Both low and high frequency ultrasound examination is appropriate for the identification of diverticula. The diverticula appear in the US image as reduced gut signature due to the absence/thinning of muscularis propria, or as bright “ears” out of the intestinal wall with acoustic shadow caused by the presence of intradiverticular gas[48]. In case of diverticulitis, intestinal wall thickening, pericolic inflammation and fluid could be detected beside the diverticula.…”