What radiologists should know about tomographic evaluation of acute diverticulitis of the colon. Acute diverticulitis of the colon is a common indication for computed tomography, and its diagnosis and complications are essential to determining the proper treatment and establishing the prognosis. The adaptation of the surgical classification for computed tomography has allowed the extent of intestinal inflammation to be established, the computed tomography findings correlating with the indication for treatment. In addition, computed tomography has proven able to distinguish among the main differential diagnoses of diverticulitis. This pictorial essay aims to present the computed tomography technique, main radiological signs, major complications, and differential diagnoses, as well as to review the classification of acute diverticulitis.
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What radiologists should know about tomographic evaluation of acute diverticulitis of the colon. Acute diverticulitis of the colon is a common indication for computed tomography, and its diagnosis and complications are essential to determining the proper treatment and establishing the prognosis. The adaptation of the surgical classification for computed tomography has allowed the extent of intestinal inflammation to be established, the computed tomography findings correlating with the indication for treatment.
In addition, computed tomography has proven able to distinguish among the main differential diagnoses of diverticulitis. This pictorial essay aims to present the computed tomography technique, main radiological signs, major complications, and differential diagnoses, as well as to review the classification of acute diverticulitis. Diverticula are small sacs of mucosa and submucosa that protrude through the muscle layer of the wall of the intestinal loop, between the taenia coli and the mesentery, at the point of penetration of the blood vessel.
Imaging tests play a crucial role in the appropriate management of ACD. This pictorial essay aims to present the CT examination technique and the main radiological signs of ACD.
We also review its classification, main complications, and differential diagnoses. For the CT evaluation of patients with suspected ACD, certain protocol options can be adopted depending on the clinical condition of each patient, and the contrast agent can be administered via the intravenous, rectal, or oral route.
It is recommended that the image acquisition extend from the diaphragm to the pubic symphysis 3. The technical parameters kV and mAs should be adjusted depending on the waist circumference of the patient, in order to optimize the image quality and radiation dose 3.
The contrast enhancement of the colonic loops facilitates the detection of ACD and its complications, such as perforation, fistulas, and abscesses. The introduction of air and water into the rectum does not interfere with CT colonoscopy or CT angiography. Images can be acquired at 60—90 s after initiation of the contrast administration 4. The use of the oral contrast agent is less frequent in the literature and in daily practice, due to the long preparation time and the large volume to be ingested 4.
Intravenous contrast-enhanced axial CT of the abdomen, showing the diverticulum with discrete wall thickening arrow and increased attenuation of pericolonic fat. Intravenous and rectal contrastenhanced axillary CT, in the axial plane, showing increased mesenteric fat attenuation arrow adjacent to the inflammatory process in the diverticula. C : Signs of intestinal perforation.
Intravenous contrast-enhanced abdominal CT, in the axial plane, showing pneumoretroperitoneum arrows secondary to diverticulitis.
Intravenous contrast-enhanced abdominal CT, in the axial plane, showing heterogenous fluid collections arrows surrounded by a hyperintense halo with contrast enhancement.
Rectal contrast-enhanced CT of the abdomen, in the sagittal plane, showing a fistulous pathway between the inflamed colonic segment and the vagina colovaginal fistula. The diagnostic hypothesis of fistula can be suggested when there is inflammatory tissue or obliteration and increased density of the fat between the colon and the adjacent organs, as well as intraluminal gas in the bladder, vaginal canal, or other lumen.
In , Hinchey et al. When the abscess is exclusively pericolonic, it is categorized as stage I, whereas it is categorized as stage II when it extends to the pelvis. When purulent peritonitis occurs, the disease is categorized as stage III. When there is peritoneal dissemination of feces, secondary to a large perforation of the loop, it is categorized as stage IV acute diverticulitis 6. With the advent of CT in the s, new information could be obtained, which led to various modifications in the initial classification system.
Because the Hinchey classification could be applied accurately only in patients who had undergone surgery, it was necessary to create a radiological staging system to assist in the management of acute diverticulitis in patients treated conservatively or with guided punctures 6.
Some surgical guidelines regarding ACD 6 are based on the modifications made to the Hinchey classification by Wasvary et al. Intravenous contrast-enhanced abdominal CT, in the axial plane, showing colonic diverticula arrow , with discrete wall thickening. Abdominal CT, in the coronal plane, without contrast. Note the wall thickening of the descending colon, accompanied by a perforated diverticulum at the mesenteric border arrow and increased density of the adjacent fat, without any fluid collections.
Intravenous contrast-enhanced abdominal CT, in the coronal plane, showing wall thickening of the sigmoid, with an adjacent pericolonic abscess arrows. Intravenous and rectal contrast-enhanced axial CT of the abdomen.
Note the thickened and finely heterogeneous walls of the sigmoid arrows in A and the hepatic abscess arrows in B related to the inflammatory process in the colon. Intravenous and rectal contrast-enhanced axial CT of the abdomen showing diverticulitis with multiple abscesses arrow in the inframesocolic region and pneumoperitoneum, together with generalized peritonitis. The most recent classification systems divide ACD into two groups: complicated and uncomplicated.
Uncomplicated ACD is characterized only by thickening of the wall of the diverticula, with increased pericolonic fat density. Complicated ACD is divided into stages. In stage 1A, pericolonic air bubbles, with little fluid, can be seen, and there is no abscess. Mild and moderate cases of ACD, with only mesenteric fat densification or with small abscesses, can be managed conservatively.
Abscesses greater than 5 cm in diameter can be treated with percutaneous drainage or surgery. However, patients presenting with purulent, fecal peritonitis should be treated surgically 2 , 7.
The most common such pathway is a colovesical fistula, which manifests as thickening of the bladder adjacent to thickening of the colonic loop, together with air within the bladder 3 , 4 , as depicted in Figure 6. The inflammatory process adjacent to the urinary tract can exert a mass effect, causing ureteral obstruction.
A similar mechanism can occur in the digestive tract itself, resulting in obstruction that leads to acute abdomen 4. Diverticulitis is a common cause of phlebitis or thrombosis of the portal vein, characterized by filling defects or gas within the mesenteric or portal system vessels Figure Complications include septic embolism, sepsis, venous rupture, and pulmonary thromboembolism 8. Intravenous and rectal contrast-enhanced axial CT of the abdomen showing a thrombus within the superior mesenteric vein arrow in A , together with acute perforated and blocked diverticulitis arrow in B , in a patient with diabetes.
The inflammatory process is disseminated via the mesenteric veins and can thus reach the liver, generating a hepatic abscess. If the abscess is bulky, it causes right-sided diaphragmatic elevation, pleural effusion, and atelectasis 4 , 8. The main differential diagnosis of ACD is adenocarcinoma of the colon, in which the wall thickening is asymmetrical and eccentric, with an abrupt transition to the normal loop, producing the so-called "shoulder sign" Figure Increased numbers of lymph nodes or lymph node enlargement adjacent to the thickened colon segment also suggest neoplasia, as do signs of distant dissemination of the disease, such as liver and lung metastases 9.
When the clinical data are inconclusive, optical colonoscopy is indicated, although it should be performed only after resolution of the acute condition Intravenous and rectal contrast-enhanced coronal CT of the abdomen, showing asymmetric wall thickening in the descending colon arrow , with an abrupt transition to the normal loop the shoulder sign. Infectious enterocolitis can mimic diverticulitis, in terms of the clinical and laboratory findings. In most cases of infectious enterocolitis, the CT scan is normal or shows long, circular, symmetrical segments of intestinal loops with thickened walls, with homogeneous contrast enhancement.
Multiple air-fluid levels can be present, as can ascites and inflammation of pericolic fat 4. The main advantages of using CT for the diagnosis of acute diverticulitis are related to the information provided regarding the extent of the extraluminal process. In addition, CT can be used in order to guide interventional procedures. CT has been considered the exam of choice in the diagnosis of ACD and its complications, allowing the establishment of a treatment strategy that is tailored to the extent and severity of the disease.
In most cases, using an examination technique aimed at clinical suspicion, together with systematic evaluation of the examination findings, makes it possible to establish a precise diagnosis with high accuracy. Rio de Janeiro: Editora Sarvier; Guidelines of diagnostics and treatment of acute left-sided colonic diverticulitis.
Dig Surg. Porto Alegre: Artmed; CT evaluation of the colon: inflammatory disease. Frequency, sensitivity, and specificity of individual signs of diverticulitis on thin-section helical CT with colonic contrast material: experience with cases.
Review of current classifications for diverticular disease and a translation into clinical practice. Int J Colorectal Dis.
A proposal for a CT driven classification of left colon acute diverticulitis. World J Emerg Surg. Pylephlebitis associated with diverticulitis. South Med J. Differentiating sigmoid diverticulitis from carcinoma on CT scans: mesenteric inflammation suggests diverticulitis. Is colonoscopy necessary after computed tomography diagnosis of acute diverticulitis?
Intest Res. Mailing address: Dr. Luis Ronan Marquez Ferreira Souza. Uberaba, MG, Brazil, E-mail: luisronan gmail. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Services on Demand Journal. Pictorial Essay What radiologists should know about tomographic evaluation of acute diverticulitis of the colon.
Abstract Acute diverticulitis of the colon is a common indication for computed tomography, and its diagnosis and complications are essential to determining the proper treatment and establishing the prognosis. Received: December 02, ; Accepted: April 04, How to cite this article.
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Review of current classifications for diverticular disease and a translation into clinical practice
Enfermedad diverticular: mitos y realidades. Diverticular disease: myths and realities. Santiago, Chile. Correspondencia a :. Diverticulosis and diverticular disease of the colon are common conditions in Western countries. The incidence and prevalence of these diseases are increasing and becoming significant for health systems. A growing body of knowledge is shifting the paradigm of the pathogenesis and treatment of diverticular disease.
Clasificación de Hinchey
Hinchey Classification is used to describe perforations of the colon due to diverticulitis. The classification was developed by Dr. Diverticulosis the presence of bowel diverticula is an essentially ubiquitous phenomenon. With age, all people develop 'out-pouching' of the bowel wall as pressure from the inside of the bowel pushes the mucosa outwards. The pouches diverticula occur where there is a gap between or weakness within the muscle fibres of the bowel wall, classically at sites of vessel protrusion into the wall.