Colonic diverticulitis: diagnostic value and appearance of inflamed diverticula–sonographic evaluation

Acute bowel inflammation frequently originates from thin-walled diverticula of the colon. Not the presence of diverticula, but the demonstration of an inflamed diverticulum, is diagnostic of diverticulitis in cases of bowel wall thickening and pericolic inflammation. The aim of this study was to investigate the sonographic appearance and detectability of inflamed diverticula. One hundred seventy-five consecutive patients with clinically suspected diverticulitis underwent sonographic examination. Outpouchings from the colonic wall centred in the pericolic inflammation were considered inflamed diverticula. Depending on the sonographic appearance they were divided into four groups: hypoechoic; predominantly hyperechoic; hyperechoic with surrounding hypoechoic rim; and hyperechoic with acoustic shadowing. Sonography showed inflamed diverticula in 79 (77%) of 102 patients with diverticulitis. Inflamed diverticula were hypoechoic in 37%, predominantly hyperechoic in 4%, hyperechoic with surrounding hypoechoic rim in 41% and hyperechoic with acoustic shadowing in 18% of patients. In 23 (23%) of 102 patients no inflamed diverticulum was demonstrable. This group included 17 patients with complicated diverticulitis and 6 false-negative cases. An inflamed diverticulum as a sign of diverticulitis yielded an overall sensitivity of 77% and a specificity of 99%. Sensitivity in uncomplicated disease was 96%. In patients with uncomplicated diverticulitis an inflamed diverticulum is a sign of diverticulitis with excellent sensitivity and specificity, usually with solitary and less frequently with more than one inflamed diverticulum being demonstrable. In patients with complicated diverticulitis an inflamed diverticulum is often not detectable.     

The role of spiral computed tomography in sigmoid diverticulitis and the diagnostic-therapeutic implications

PURPOSE: Colonic diverticula are saccules made of colonic mucosa and submucosa that herniate from the colonic lumen through the muscular layer of the wall where straight vessels penetrate. Diverticula are localized in the sigmoid colon in 95% of cases. Bacteria pooling in the lumen may cause lumen erosion and eventually perforation. CT is a useful technique in this condition because it can demonstrate intra- and/or extramural inflammation. Aim of this retrospective study was to assess the capabilities of contrast-enhanced helical Computed Tomography (CT) in sigmoid diverticulitis, especially relative to selection of the appropriate treatment. MATERIAL AND METHODS: We retrospectively reviewed the findings of 41 patients referred to our emergency department for diverticulitis. CT scans were performed 65 seconds after i.v. injection of nonionic contrast material (3 mL/s, 120 mL in all) administered by a CT-power injector. The following 7 CT findings were considered at least suggestive of acute diverticulitis: focal wall thickening, intramural abscess, inflammatory changes in the sigmoid mesentery root, pericolic fat inflammation or pericolic abscess formation, fistula, peritonitis. CT results were compared with surgical and physical findings. RESULTS: Based on CT findings, diverticulitis was classified as mild (25 patients) or severe (15 patients). In mild diverticulitis we found: focal sigmoid wall thickening (6 patients), intramural abscess (3 patients), sigmoid mesentery root thickening (5 patients), edema fluid (8 patients) and phlegmon (3 patients). In severe diverticulitis we found: sigmoid mesentery abscess (6 patients), fistula (5 patients) and peritonitis (4 patients). CT findings were questionable in 1 case and thus we could not exclude a perforated carcinoma. CONCLUSION: Contrast-enhanced helical CT is the imaging modality of choice in assessing mild or severe acute diverticulitis because it provides useful information for appropriate treatment planning in the emergency setting. This technique is most useful in questionable cases and in patients with suspected severe diverticulitis where a choice must be made between different treatment options.     

Does MR enterography offer added value after a recent CT in the evaluation of abdominal pain in Crohn's disease patients?

PurposeTo determine if there is added value in performing MR enterography shortly after a contrast-enhanced CT of the abdomen and pelvis in patients with Crohn's disease presenting with acute abdominal pain.Materials and methodsA total of 45 consecutive patients who underwent MRE examination <7 days after a CT met our strict inclusion criteria. Independent and blinded review of both MRE and CT exams was performed by two abdominal radiologists.ResultsThere were no significant differences in detection of various findings associated with Crohn's disease between modalities. These findings included abscess, fistula, bowel wall thickening, free fluid, stricture, and bowel obstruction. There was moderate interobserver agreement with CT (Kappa: 0.52, 95% CI: [0.4–0.6]) and fair with MRE (Kappa: 0.36, 95% CI:[0.3 = 0.5]).ConclusionThe routine use of MRE after a diagnostic CT should be avoided, as it provides no additional valuable information, at the expense of extra patient risks, discomfort, and higher health care costs.     

Primary epiploic appendagitis: CT diagnosis

The purpose of this study was to analyze the CT signs of primary epiploic appendagitis. A retrospective search of the CT database over 12 months for this diagnosis revealed 11 cases. The clinical findings were recorded. Softcopy CT images were reviewed by two experienced abdominal radiologists (KS, DM) for location of lesion, size, shape, presence of central hyperdense focus, degree of bowel wall thickening, mass effect, and ancillary signs. Abdominal pain was the primary symptom in all patients. Preliminary diagnoses were appendicitis (n=2), diverticulitis (n=5), pancreatitis (n=1), ovarian lesion (n=1), or unknown (n=2). Abdominal examination and white blood cell count were uninformative. CT examination revealed a solitary (n=11), ovoid (n=9) fatty lesion with some soft tissue stranding adjacent to the left colon (n=6), transverse colon (n=3), or right colon (n=2). Central hyperdensity (n=5), mild bowel wall thickening (n=2), and parietal peritoneal thickening (n=4) were also seen. In 4 patients the lesions were not visible on follow-up CT examination performed 23–184 days later. Primary epiploic appendagitis can clinically mimic other, more serious inflammatory conditions. Knowledge of its findings on CT would help the radiologist make the diagnosis and allow a more conservative approach to patient care.     

US and CT findings in complicated Meckel diverticulum

AIM: Meckel s diverticulum is the most common congenital abnormality of the small bowel. It may be silent or symptomatic when complicated by hemorrage, intestinal occlusion, diverticulitis and umbilical fistulas. Radiologic diagnosis is often difficult because abdominal plain radiography and ultrasound are not sufficiently specific; CT is most accurate in differential diagnosis. MATERIAL AND METHODS. 11 patients (age 5-69 ys) were studied. Clinical symptoms included acute abdomen (4 pts), intestinal occlusion (3 pts), abdominal pain (4 pts), fever (5 pts). Radiological studies were abdominal plain radiography (8 pts), ultrasound (5 pts), CT (9 pts). RESULTS: Abdominal plain radiography depicted signs of intestinal occlusion (4 pts) and perforation (1 pts); in 4 pts the signs were non diagnostic. Ultrasound showed an abscess in the pelvis (2 pts), dilatation and wall-thickening of an intestinal loop (2 pts), intestinal invagination (1 pts); it was not diagnostic in 3 pts. CT was not diagnostic in 3 pts; in 2 pts it showed an abscessual fluid collection in the pelvis, adherent to intestinal loops, with flogosis of the perivisceral fat; in 1 pt it revealed perforation; in 4 cases it was specific showing inversion of the diverticulum in an intestinal loop (2 pts) or a tubular fluid-filled structure, with thickened walls and contrast enhancement, which was interpreted as a inflammatory diverticulum (2 pts). DISCUSSION: Our series confirms the difficulty of diagnosing Meckel s diverticulum in an acute setting. Abdominal plain radiography only allowed to diagnose intestinal occlusion or perforation. Ultrasound revealed abscessual collections in the pelvis, fluid distention of the diverticulum, segmental thickening of the intestinal walls and invagination. CT proved to be more specific showing signs suggestive of correct diagnosis in 6 pts. In particular, evidence of an intraluminal prolonged mass with central area of fat density and peripherral collar was considered suggestive of intraluminal invagination of Meckel s diverticulum. Another diagnostic sign is the evidence of a tubular fluid-filled structure, with thickened, enhanced walls. In 2 cases CT showed an abscessual collection with gas-fluid level (complication of perforation) confirming the need for surgery. CONCLUSION: Meckel s diverticulum is a not uncommon condition that in some cases is complicated, resulting in acute abdomen. Preoperative radiological diagnosis can be suspected in the presence of suggestive signs, more often depicted by CT.     

Jejuno-ileal diverticulitis with localized perforation: CT and US findings

Purpose

To describe the computed tomography and ultrasound findings of five cases of small bowel diverticulitis with localized perforation.

Material and methods

Our database, from April 2003 to August 2007, was reviewed and five cases of small bowel diverticulitis were identified.

Results

Jejuno-ileal diverticulitis with covered perforation usually presents as wall thickening of a small bowel loop and an adjacent inflammatory mass containing air bubbles.

Conclusion

Small bowel diverticula are rare and mostly asymptomatic. They become clinically relevant when complications arise, such as diverticulitis. The symptoms of jejuno-ileal diverticulitis are non-specific and the diagnosis is performed mainly by imaging studies.     

Small bowell volvulus - combined radiological findings]

PURPOSE: We retrospectively evaluated the radiological findings observed at plain abdominal film, abdominal sonography and abdominal CT performed in 66 patients with surgically proven small bowel volvulus. MATERIAL AND METHODS: Sixty-six patients (35 women and 31 men, ranging in age 38-77 years) with surgically proven small bowel volvulus were submitted to plain film, sonography and CT of the abdomen. Abdominal plain film was performed in the upright position (postero-anterior view) in 46 cases, and in the supine position in 20 cases. On plain abdominal film we evaluated the following findings: bowel loops dilatation, air-fluid levels and site of obstruction. At abdominal US, performed with 3.5 e 7.5 MHz probes, we retrospectively searched for: bowel loop dilatation, bowel wall thickening, peristalsis alteration, extraluminal fluid. CT was performed with a helical unit (thickness 4 mm, reconstruction interval 4 mm, pitch 1.5), after intravenous contrast agent (120 ml) infusion (3 ml/s, 55 s acquisition delay from bolus starting) and using a power injector. The following CT findings were searched for: whirl sign, beak sign, extraluminal fluid, bowel loop dilatation, bowel wall thickening, bowel wall or mesenteric alterations. RESULTS: Plain abdominal film showed the following findings: air-fluid levels (92.4% of cases), bowel loops dilatation (71.2%), site of obstruction (42.4%). Abdominal sonography demonstrated bowel loop dilatation (48.5%), extraluminal fluid (48.5%), peristalsis alteration (27.3%), bowel wall thickening (27.3%). The most frequent CT findings were: bowel loop dilatation (95.5%), bowel wall thickening (78.8%), beak sign (69.7%), mesenteric alterations (66.7%), extraluminal fluid (54.5%), whirl sign (13.6%). CONCLUSIONS: Air-fluid levels and bowel loop dilatation were the most frequent radiological findings in our series. Plain abdominal film allowed us to identify signs of obstruction, whereas signs of bowel wall necrosis were accurately shown by abdominal CT.     

Computed tomography in the evaluation of diverticulitis

Computed tomography (CT) was performed in 43 cases of colonic diverticulitis and compared with the contrast-enema examination (CE) in 37 patients. Findings on CT included inflammation of the pericolic fat in 98% of cases, diverticula in 84%, thickening of the colon wall in 70%, a pericolic abscess in 35%, peritonitis in 16%, a fistula in 14%, colon obstruction in 12%, and intramural sinus tracts in 9%. Secondary findings included a distant abscess in 12% and ureteral obstruction in 7%. In addition to detecting ureteral and bladder involvement and distant abscess formation, CT was preferable for demonstrating the extent of pericolic inflammation, which was underestimated with CE in 41% of patients. Differential diagnosis of the CT findings is discussed. The authors indicate that CT should be the initial procedure in patients with suspected diverticulitis, particularly when CE is contraindicated.     

Acute colonic diverticulitis in a community-based hospital: CT evaluation in 138 patients

The purpose of this research is to retrospectively analyze computed tomography (CT) findings of patients with acute colonic diverticulitis presented to a community-based hospital. During a 1-year period from May 2004 to April 2005, CT scans of 138 patients [mean age 62.3 years (SD 14.9), range 30–100 years] with clinical diagnosis of diverticulitis were analyzed. Of the 138 patients, 136 CT scans were performed with oral and intravenous contrast administration except in two patients who received only oral contrast. Twenty-eight patients (28/138, 20.3%) had diverticulosis, 77 (77/138, 55.8%) had uncomplicated diverticulitis, and 33 (33/138, 23.9%) had complications. Left-sided diverticulitis predominated (137/138, 99.3%). Colonic diverticula were identified in almost every patient (136/138, 98.6%); the majority had moderate colonic wall thickening (82/110, 74.5%) and moderate pericolonic inflammation (65/110, 59.1%). Isolated extraluminal air bubbles (19/33, 57.6%) were the most commonly seen complication, followed by abscess (15/33, 45.5%). Bowel obstruction (2/33, 6.1%) and pylephlebitis (1/33, 3.0%) were less commonly seen but were observed as significant abnormalities. Complicated diverticulitis was less prevalent in this community hospital setting, in contrast with referral medical centers. Common CT findings of diverticulitis included presence of diverticula, moderate wall thickening, and pericolonic inflammation. Isolated air bubbles were the most commonly seen complication followed by abscess.     

Computed tomography findings of acute gastric peptic ulcer

PurposeTo report the computed tomography (CT) findings of acute peptic ulcer disease (PUD) and to evaluate the usefulness of contrast media for diagnosis.MethodsThis retrospective study included 51 patients diagnosed with acute gastric peptic ulcer by endoscopy. Using a κ analysis, two radiologists independently reviewed contrast-enhanced emergency CTs performed within 24 h of endoscopy. Evaluation findings included low-attenuation wall thickening, focal wall thickening, focal luminal outpouching, perigastric fat stranding, ascites, adjacent lymphadenopathy, and high-density gastric contents. Of the 51 patients, 48 underwent both non–contrast-enhanced and contrast-enhanced CT, and two radiologists also evaluated the presence or absence of these findings on a non-contrast-enhanced CT. McNemar's test was used to evaluate the contrast media's usefulness.ResultsInterobserver variability of perigastric fat stranding revealed substantial agreement between evaluators, and other findings had almost perfect agreement. High-density gastric contents were the most recognized findings (60%). Low-attenuation focal wall thickening and focal luminal outpouching were observed in relatively large numbers (~50%) of the cases on contrast-enhanced CT. The CT examinations using contrast media provided significantly higher detectability of low-attenuation wall thickening and focal luminal outpouching than CT examinations without using contrast media.ConclusionAcute PUD can be suspected in patients with nonspecific abdominal symptoms in whom emergency CT shows high-density gastric contents, focal low-attenuation wall thickening, and/or focal luminal outpouching. Our study showed that contrast media are useful for diagnosis.     

CT features of systemic lupus erythematosus in patients with acute abdominal pain: emphasis on ischemic bowel disease

PURPOSE: To evaluate the computed tomographic (CT) features of systemic lupus erythematosus (SLE) in patients with acute abdominal pain. Special emphasis was placed on the analysis of ischemic bowel disease. MATERIALS AND METHODS: The authors retrospectively reviewed the images from 39 abdominal CT examinations performed in 33 patients with SLE and acute abdominal pain. Images were evaluated for bowel wall changes, mesenteric changes, fluid collection, retroperitoneal lymphadenopathy, peritoneal enhancement, and hepatomegaly as well as for changes in other abdominal organs. Ischemic bowel disease was diagnosed if at least three of the following signs were seen: bowel wall thickening, target sign, dilatation of intestinal segments, engorgement of mesenteric vessels, and increased attenuation of mesenteric fat. RESULTS: Thirty-one (79%) of the 39 examinations had CT findings diagnostic of ischemic bowel disease, including symmetric bowel wall thickening (n = 29), target sign (n = 26), and mesenteric vascular engorgement and haziness (n = 31). In 24 cases, bowel wall thickening was multifocal, with variable length, and did not appear to be confined to a single vascular territory. CONCLUSION: The most common CT finding in patients with SLE and acute abdominal pain is ischemic bowel disease. CT is useful for detecting the primary cause of gastrointestinal symptoms, planning treatment, and monitoring for infarction or perforation.     

The Accuracy of Colorectal Cancer Detection by Computed Tomography in the Unprepared Large Bowel in a Community-Based Hospital

Purpose

This retrospective study examined the performance of general radiologists in a community-based hospital in detecting colorectal cancer (CRC) with computed tomography (CT) in the unprepared large bowel.

儿童腹腔脓肿的CT诊断

目的探讨ＣＴ对儿童腹腔脓肿的诊断价值。方法对２３例经手术和穿刺针吸证实的腹腔脓肿的ＣＴ表现进行分析，急性阑尾炎１３例，升结肠穿孔１例，美克尔憩室炎２例，感染源不明确７例。１９例行平扫与增强检查，４例仅平扫检查。结果脓液ＣＴ值与病程及致病菌种类无关，脓液量与病程呈正相关。５２％脓肿内见到气体影，２２％脓肿内见到小钙化斑。病程１周以上者全部见不均匀厚壁强化的脓肿壁。结论脓肿内见到小钙化斑和气体影像具有特征性，脓腔内较大气液平面提示肠瘘存在，脓肿内无气体影不能排除肠瘘。     

Multisystem inflammatory syndrome in children associated with SARS-CoV-2: extracardiac radiological findings

Objective:Multisystem inflammatory syndrome in children (MIS-C) is seen as a serious delayed complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The aim of this study was to describe the most common imaging features of MIS-C associated with SARS-CoV-2.Methods:A retrospective review was made of the medical records and radiological imaging studies of 47 children (26 male, 21 female) in the age range of 25 months–15 years who were diagnosed with MIS-C between August 2020 and March 2021. Chest radiographs were available for all 47 patients, thorax ultrasound for 6, chest CT for 4, abdominal ultrasound for 42, abdomen CT for 9, neck ultrasound for 4, neck CT for 2, brain CT for 1, and brain MRI for 3.Results:The most common finding on chest radiographs was perihilar–peribronchial thickening (46%). The most common findings on abdominal ultrasonography were mesenteric inflammation (42%), and hepatosplenomegaly (38%, 28%). Lymphadenopathy was determined in four patients who underwent neck ultrasound, one of whom had deep neck infection on CT. One patient had restricted diffusion and T2 hyperintensity involving the corpus callosum splenium on brain MRI, and one patient had epididymitis related with MIS-C.Conclusion:Pulmonary manifestations are uncommon in MIS-C. In the abdominal imaging, mesenteric inflammation, hepatosplenomegaly, periportal edema, ascites and bowel wall thickening are the most common findings.Advances in knowledge:The imaging findings of MIS-C are non-specific and can mimic many other pathologies. Radiologists should be aware that these findings may indicate the correct diagnosis of MIS-C.     

Frequency,sensitivity, and specificity of individual signs of diverticulitis on thin-section helical CT with colonic contrast material: experience with 312 cases

OBJECTIVE: The aim of our study was to determine the frequency, sensitivity, and specificity of the individual signs of diverticulitis using helical CT with colonic contrast material. MATERIALS AND METHODS: Between March 1997 and September 1999, 312 patients with suspected diverticulitis were examined on helical CT using rectally administered colonic contrast material. CT scans that were positive for diverticulitis or indeterminate were rereviewed by two radiologists; CT interpretations were correlated with patients' clinical courses and surgical findings. RESULTS: One hundred fourteen (37%) of the 312 CT scans were interpreted as positive for diverticulitis; 192 scans (61%), as negative; six scans (2%), as indeterminate. Of the 114 scans that were positive for diverticulitis, 109 (96%; sensitivity 96%, specificity 91%) showed bowel wall thickening; 108 (95%; sensitivity 96%, specificity 90%), fat stranding; 104 (91%; sensitivity 91%, specificity 67%), diverticula; 57 (50%; sensitivity 50%, specificity 100%), fascial thickening; 51 (45%; sensitivity 45%, specificity 97%), free fluid; 49 (43%; sensitivity 43%, specificity 100%), inflamed diverticula; 34 (30%; sensitivity 30%, specificity 100%), free air; 18 (16%; sensitivity 16%, specificity 100%), "arrowhead" signs; nine (8%; sensitivity 8%, specificity 99%), abscesses; four (4%; sensitivity 4%, specificity 100%,), phlegmons; five (4%; sensitivity 4%, specificity 99%), intramural air; two (2%; sensitivity 2%, specificity 100%), intramural sinus tracts. Overall CT interpretation had a sensitivity of 99%, a specificity of 99%, a positive predictive value of 99%, a negative predictive value of 99%, and an overall accuracy of 99%. CONCLUSION: The two most frequent signs of diverticulitis were bowel wall thickening (96%) and fat stranding (95%). Less frequent but highly specific signs were fascial thickening (50%), free fluid (45%), and inflamed diverticula (43%).     

Limitations in the CT diagnosis of acute diverticulitis: comparison of CT, contrast enema, and pathologic findings in 16 patients

Pitfalls in CT diagnosis of acute diverticulitis were investigated in 16 patients with the disease who had misleading or equivocal CT features. The CT appearance was correlated with contrast enemas (13 cases) and with surgical assessment and pathologic evaluation of resected specimens (12 cases). Limitations in the CT diagnosis were related to (1) marked thickening of the colonic wall, between 1 and 3 cm in cross section simulating colonic neoplasm (all patients); (2) inability to visualize small amounts of fibropurulent exudate in the absence of pericolic inflammatory changes (eight patients); (3) failure to detect discrete intramural abscess (five patients). Resected surgical specimens available in 12 cases proved that colonic wall thickening was caused by muscular hypertrophy and various degrees of submucosal inflammation, edema, fibrosis, or focal organized inflammatory tissue. Contrast enema was useful in 10 out of 13 patients by excluding carcinoma of the colon and confirming the diagnosis of acute diverticulitis.     

Abdominal wall abscess as the presenting sign in carcinoma of the colon: report of 4 cases

PURPOSE: We report four cases of unusual presentation of colonic cancer revealed by an abscess of the abdominal wall. MATERIALS AND METHODS: Our study included 3 men and 1 women ranging in age from 33 to 66 years presenting with abdominal wall abscess (in the left anterior abdominal wall in 2 patients and in the quadratus lumborum muscle in the other 2 patients). Our cases were listed from the departments of radiology and abdominal surgery of Sahloul hospital from 1995 through 2000. Ultrasonography (US) and computed tomography (CT) were performed in all cases; barium enema in three. RESULTS: US and CT revealed segmental colonic wall thickening (left colon in three patients and right colon in one patient). The diagnosis of colonic cancer was reached by colonoscopy with biopsy in all 4 cases. All of our patients underwent surgical treatment. CONCLUSION: In this era of newer diagnostic imaging modalities, US and CT must frequently be used in the evaluation of patients with abdominal wall abscess, to depict intra-abdominal infection and especially malignant lesion causing abdominal wall abscess.     

Small bowel rupture after blunt trauma: Computed tomographic signs and their sensitivity

The purpose of this study is to describe the characteristic computed tomographic (CT) signs of small bowel perforation after blunt abdominal trauma and to evaluate their sensitivity. Nineteen preoperative CT scans were obtained from 16 patients with surgically proven small bowel rupture secondary to blunt abdominal trauma. Only the CT findings described in the original CT reports were used. Eleven of 19 CT scans (58 %) had findings that were unequivocal for bowel rupture (i.e., extraluminal air and/or extravasation of oral contrast medium). Seven CT scans (37 %) had findings that were suggestive of severe small bowel injury (i.e., focal small bowel wall thickening and/or free peritoneal fluid without other accompanying organ injuries). In all, 95 % of cases of small bowel rupture had either pathognomonic or suggestive CT findings. One CT scan did not demonstrate small bowel wall thickening, although a hemoperitoneum was present. CT is a sensitive method for suggesting severe small bowel injury and rupture secondary to blunt abdominal trauma.     

Why can we not see a normal appendix on CT? An evaluation of the factors influencing nonvisualization of a normal appendix by 64-slice MDCT

PurposeThe aim of this study was to identify the factors that prevent the visualization of a normal appendix by 64-slice MDCT.Materials and methodsThirty-nine consecutive patients with a normal appendix not visualized during routine abdominal CT and without a history of abdominal surgery were selected for this study. In addition, 100 consecutive patients with a clearly visualized normal appendix by CT were selected as controls. Two radiologists, by consensus, evaluated MDCT images for cecum level, pericecal fat content, presence of small bowel dilatation, presence of pericecal fluid, presence of cecal wall thickening, and identification of the ileocecal valve.ResultsPatients with a nonvisualized normal appendix had a significantly lower cecum level, minimal pericecal fat, and a higher amount of pericecal fluid and were less likely to have an identified ileocecal valve (46.2%, 79.5%, 17.9%, and 76.9%, respectively) than patients with a clearly visualized appendix (18%, 9%, 4%, and 100%, respectively) (all P<.01). The presence of small bowel dilatation and cecal wall thickening was not statistically significant (7.7% vs. 8% and 7.7% vs. 9%, respectively) (all P>.01).ConclusionThe factors that influence the nonvisualization of a normal appendix on MDCT images are as follows: a low cecum level, minimal pericecal fat, presence of pericecal fluid, and nonidentification of the ileocecal valve.