Segmental omental infarction in a 9-year-old girl

Omental infarction is an unusual cause of acute abdominal pain in children. The clinical presentation may mimic cholecystitis or appendicitis, but crosssectional imaging by ultrasound or computed tomography will demonstrate characteristic findings in a location corresponding to the patient's point of maximal tenderness. These findings consist of an ovoid mass in the omental fat with surrounding inflammatory changes.     

Omental infarction associated with right-sided heart failure

A 31-year-old man with a known congenital heart disease presented with cardial decompensation and an acute abdomen with tenderness in the right inferior abdominal quadrant. Because infectious parameters were slightly elevated, acute appendicitis was suspected. A CT scan showed an isolated focal infiltration of the omentum, superficial to the ascending colon, small amounts of ascites, and dilated hepatic and mesenteric veins. Laparoscopic resection and histopathologic examination confirmed hemorrhagic omental infarction due to thromboses of several small omental veins. This is a report on the pathogenesis, differential diagnoses, and CT findings of omental infarction. Received: 14 July 1999; Revised: 12 October 1999; Accepted: 4 November 1999     

Omental infarction as a delayed complication of abdominal surgery.

Omental infarction, an uncommon cause of acute abdominal pain, is the result of compromised perfusion to the greater omentum. Although its etiology remains uncertain, predisposing factors include obesity [Surg. Today 30 (2000) 451], strenuous activity [N. Z. Med. J. 111 (1998) 211], trauma, and idiopathic omental torsion. Often confused with acute appendicitis or cholecystitis on clinical grounds [Surg. Today 30 (2000) 451], its diagnosis has traditionally been one of exclusion, based on intraoperative and pathologic findings. This diagnosis can be made radiologically based on the characteristic findings of an inflammatory mass containing fat and fluid. We describe a case of right lower quadrant omental infarction temporally related to bowel surgery.     

CT of acute appendicitis: can diagnostic accuracy serve as a practical performance metric for readers specialized in abdominal imaging?

PurposeTo investigate diagnostic accuracy for acute appendicitis at computed tomography (CT) as a performance metric for radiologists specialized in abdominal imaging.Materials and MethodsWe retrospectively identified six attending abdominal imagers who each independently interpreted over 100 CT studies for suspected acute appendicitis.ResultsThe mean number of studies per reader was 311 (range, 129–386). Mean reader diagnostic accuracy was 95.0% (range, 91.4–97.1%). Only one had a diagnostic accuracy (91.4%) that was significantly lower than all others.ConclusionDiagnostic accuracy for acute appendicitis at CT may be an impractical performance metric for radiologists specialized in abdominal imaging.     

Intraabdominal fat necrosis

The processes that course with intraabdominal fat necrosis often manifest with acute or subacute abdominal pain; these clinical findings can be caused by various conditions, including epiploic appendagitis, omental infarction, encapsulated fat necrosis, mesenteric panniculitis, appendicitis, diverticulitis, and certain neoplasms. In this context, although the anatomic location of the pain and accompanying symptomatology can help orient the diagnosis, there is a risk of unnecessary surgery. Imaging tests like ultrasonography and especially computed tomography are essential for diagnosing intraabdominal fat necrosis. Radiologists must be familiar with the characteristic findings for all the conditions that can cause acute or subacute abdominal pain to ensure appropriate management and prevent unnecessary surgery.     

Segmental omental infarction

Acute right-sided abdominal pain is a common presenting symptom in the emergency department. Acute cholecystitis and acute appendicitis are the most likely etiologies for right upper and lower quadrant pain, respectively. However, other differential possibilities include right-sided diverticulitis and perforated colon carcinoma. This case report of an 18-year-old man with segmental omental infarction highlights a much less frequent, self-limited cause of right-sided abdominal pain, which is increasingly identified on computed tomography scans.     

Idiopathic segmental infarction of the greater omentum diagnosed by unenhanced multidetector-row CT and treated successfully by laparoscopy

Idiopathic segmental infarction of the greater omentum is a rare disorder presenting with nonspecific clinical symptoms that may mimic a variety of acute abdominal conditions. We describe the diagnosis and treatment of two patients who had idiopathic infarction of the greater omentum and presented with localized abdominal pain, mimicking acute cholecystitis and acute diverticulitis, respectively. Patients underwent unenhanced multidetector-row computed tomography (CT) examination, which demonstrated the characteristic features of omental infarction, consisting of a heterogeneous density fatty mass, containing hyperattenuating streaks, located in the greater omentum, between the anterior abdominal wall and the colon; a moderate amount of free peritoneal fluid was also present. There were no other pathological abdominal findings. Giving persisting and worsening symptoms, both patients underwent laparoscopy with resection of the necrotic portion of the omentum. Pathology confirmed the preoperative diagnosis. Unenhanced CT allows us to obtain a reliable diagnosis of omental infarction in patients with acute abdominal pain and may help in selecting the appropriate medical or surgical therapy.     

Accuracy of Nonenhanced CT vs Contrast-Enhanced CT for Diagnosis of Acute Appendicitis in Adults

BackgroundAcute appendicitis is one of the most common causes of acute abdominal pain requiring emergency intervention. It is often difficult for the clinician to make an accurate diagnosis due to nonspecific and overlapping clinical symptoms. Computed tomography (CT) has become the imaging modality of choice for the evaluation of suspected acute appendicitis. The main purpose of our study was to compare nonenhanced CT (NECT) with contrast-enhanced CT (CECT) for the diagnosis of acute appendicitis.Material and MethodsA total of 140 patients were enrolled in the study. Two abdominal radiologists—masked to both the clinical information and the final diagnosis—retrospectively reviewed the computed tomographic findings and made an imaging diagnosis based on (1) NECT only, (2) CECT only, and (3) both NECT and CECT. With the final diagnosis as the reference standard, the accuracy of each CT technique was estimated.ResultsThe respective sensitivity, specificity, and accuracy for NECT, CECT, and NECT + CECT for the diagnosis of acute appendicitis were 80.7%, 86.7%, and 84.3%; 86.0%, 81.9%, and 83.6%; and, 87.7%, 80.7%, and 83.6%. There was no significant difference in the diagnosis of acute appendicitis among the 3 techniques. In order to make a correct diagnosis, the presence of at least 3 imaging findings for NECT or at least 4 for CECT had the best diagnostic accuracy. We also found that 9.25 mm was the optimal cut-off threshold for the detection of patients with acute appendicitis.ConclusionOur study allowed direct comparison between NECT, CECT, and NECT + CECT combined. There was no difference in the ability of each CT technique for diagnosing patients with acute appendicitis. For a patient whom iodinated contrast media is contraindicated or a patient who has an increased risk of severe adverse reaction, we would encourage the use of NECT because it provides comparable diagnostic accuracy without further exposing such patient to the contrast media.     

Radiological features of epiploic appendagitis and segmental omental infarction

Epiploic appendagitis and segmental omental infarction are more frequently encountered with the increased use of abdominal ultrasound and Computed tomography (CT) in the radiological assessment of the patient who presents clinically with acute abdominal pain. Recognition of specific imaging abnormalities enables the radiologist to make the correct diagnosis. This is important, as the appropriate management of both conditions is often conservative. Follow-up imaging features correlate with clinical improvement.     

儿童少见大网膜梗死的MSCT诊断与鉴别诊断二例

笔者报道了2例儿童少见大网膜梗死的多层螺旋CT(MSCT)表现,归纳和总结MSCT对该病的诊断价值.儿童大网膜梗死相对比较少见,且该病的临床表现缺乏特异性,起病类似急性阑尾炎或胆囊炎.超声检查对儿童大网膜病变诊断价值有限,MSCT检查为该病的主要影像学检查方法并具有诊断特异性.在儿童继发性大网膜扭转、梗死时疾病进展较快...     

MR imaging evaluation of acute appendicitis in pregnancy

PURPOSE: To retrospectively assess the diagnostic performance of magnetic resonance (MR) imaging in pregnant patients suspected of having acute appendicitis. MATERIALS AND METHODS: The study was approved by the committee on clinical investigations and was HIPAA compliant. The informed consent requirement was waived. MR images were obtained in 51 consecutive pregnant patients (mean age, 28.3 years) who were clinically suspected of having acute appendicitis. In this protocol for pregnant patients, MR imaging is performed when findings at ultrasonography (US) are inconclusive or additional information is needed. Four patients had appendicitis, which was confirmed at surgery in three patients and at follow-up computed tomography in one patient. Initial interpretations were used for patient care and to calculate diagnostic accuracy. The appendix was considered normal at MR imaging if its diameter was less than or equal to 6 mm or if it was filled with air, oral contrast material, or both. An enlarged fluid-filled appendix (>7 mm in diameter) was considered an abnormal finding. An appendix with a diameter of 6-7 mm was considered an inconclusive finding; in those cases, the presence of periappendiceal inflammation was used for the final diagnosis. Three radiologists retrospectively assessed the visualization of the appendix by using a 5-point scale. Statistical analysis was performed by using the median and Fisher exact tests and the Spearman correlation coefficient. RESULTS: MR images were positive for appendicitis in four patients and inconclusive in three. In the three patients with inconclusive results, the appendix was not seen in two patients and was borderline enlarged (7 mm in diameter) in the third. The overall sensitivity, specificity, prevalence-adjusted positive and negative predictive values, and accuracy for MR imaging was 100%, 93.6%, 1.4%, 100%, and 94.0%, respectively. CONCLUSION: MR imaging is an excellent modality for use in excluding acute appendicitis in pregnant women who present with acute abdominal pain and in whom a normal appendix is not visualized at US.     

Ultrasound of acute GI tract conditions

Patients with acute abdominal pain are a great challenge to the radiologist. The clinical diagnosis is classically unreliable, resulting in both negative laparotomies as well as ill-advised surgical delay in a large number of patients. Ultrasound offers a non-invasive way to decrease both false-negative and false-positive diagnoses in this category of patients. This article focuses on the role of sonography in the diagnosis of acute conditions of the gastrointestinal tract tract such as appendicitis, sigmoid diverticulitis, Crohn's disease, colitis, infectious ileocecitis caused by Yersinia, Campylobacter or Salmonella, right-sided colonic diverticulitis, bowel malignancy presenting acutely, small bowel obstruction, intussusception, omental infarction, and epiploic appendagitis. The sonographic spectrum of these conditions as well as possible pitfalls are discussed using illustrative case histories.     

Right-lower-quadrant pain and suspected appendicitis in pregnant women: evaluation with MR imaging--initial experience

PURPOSE: To determine if there is a role for magnetic resonance (MR) imaging in evaluation of pregnant women with acute right-lower-quadrant pain in whom acute appendicitis is suspected. MATERIALS AND METHODS: Informed consent and institutional review board approval were obtained. Images obtained with a 1.5-T MR imager and medical records of 23 pregnant women (age range, 19-34 years; mean age, 24.7 years) who presented with acute right-lower-quadrant pain were retrospectively reviewed. MR protocol included use of transverse, coronal, and sagittal noncontiguous T2-weighted single-shot fast spin-echo (SE) sequences; transverse fat-suppressed T2-weighted fast SE sequences; transverse T1-weighted gradient-recalled-echo sequences; and transverse and coronal short inversion time inversion-recovery sequences performed through the lower abdomen and pelvis. MR findings were evaluated by two radiologists and compared with surgical and pathologic findings and clinical follow-up data. RESULTS: Appendix was detected in 20 (86.9%) of 23 patients. Seven patients underwent surgery; four had acute appendicitis, and three had ovarian torsion. Two patients with pelvic abscesses not related to appendicitis underwent percutaneous drainage. Fourteen patients were treated medically. Dilated thick-walled appendix and periappendiceal inflammation were detected in three (75%) of four patients with acute appendicitis. In one patient with appendicitis, the appendix could not be visualized, but inflammation was present in the right lower quadrant. In three patients with ovarian torsion, MR imaging demonstrated right adnexal mass or inflammation. MR imaging was used to correctly identify pelvic abscesses and healthy appendix in two patients. A healthy appendix was depicted in 17 (89.5%) of 19 patients without acute appendicitis. CONCLUSION: MR imaging shows promise for evaluation of pregnant women in whom acute appendicitis is suspected by enabling diagnosis of other possible causes of right-lower-quadrant pain, including ovarian torsion or pelvic abscesses, and demonstrating a healthy or unhealthy appendix.     

Right-sided colonic diverticulitis: CT findings.

Right-sided colonic diverticulitis is an uncommon but clinically significant condition as it closely mimics other common acute right-sided abdominal conditions like acute appendicitis and cholecystitis. CT can provide a rapid and accurate diagnosis of this condition and thereby prevent unnecessary laparotomy and surgical procedures since it is essentially a benign self-limiting condition requiring medical treatment. It is the aim of this pictorial essay to describe the CT findings and increase awareness among radiologists of this condition.     

CT Findings of Foreign Body Reaction to a Retained Endoloop Ligature Plastic Tube Mimicking Acute Appendicitis: A Case Report

Many hospitals experience one or more retained surgical instrument events with risk of patient morbidity and medicolegal problems. Identification of retained surgical instrument is important. The radiologists should be familiar with imaging finding of retained surgical instrument. In a 62-year-old female with a retained plastic tube, localized peritoneal infiltration around air-containing tubular structure mimicked acute appendicitis on abdomen computed tomography (CT), one year after laparoscopic cholecystectomy. We reported CT findings of foreign body reaction related to retained Endoloop ligature plastic tube mimicking acute appendicitis.     

The nonvisualized appendix: incidence of acute appendicitis when secondary inflammatory changes are absent

OBJECTIVE: The objective of our study was to assess the importance of nonvisualization of the appendix and its association with acute appendicitis on helical CT when secondary inflammatory changes are absent. MATERIALS AND METHODS: After we received institutional review board approval, CT scans of 366 consecutive patients obtained for lower abdominal or right lower quadrant pain and to rule out appendicitis were retrospectively reviewed. Images were reviewed by an experienced abdominal radiologist and compared with the formal interpretation. The amount of right lower quadrant and pericecal fat was quantified on a scale of 0 (none) to 2 (abundant). Patients with a nonvisualized appendix and other findings compatible with acute appendicitis-such as abscess formation, localized perforation, periappendiceal fat stranding, or appendicolith-were excluded. RESULTS: The appendix could not be visualized by both reviewers in 46 (13%) of 366 cases. CT findings indicated another cause for the patient's symptoms in 12 cases (26%), including gastrointestinal and genitourinary processes. An alternate diagnosis was subsequently reached in 11 additional patients (24%) with follow-up imaging or clinical evaluation. Only one patient (2%) with a nonvisualized appendix had acute appendicitis, proven by surgical pathology. In this patient, there was paucity of fat in the right lower quadrant. CONCLUSION: In the absence of a distinctly visualized appendix and secondary inflammatory changes, the incidence of acute appendicitis is low. Nonvisualization of the appendix even when a small amount of fat is present in the right lower quadrant may safely exclude acute appendicitis if no secondary CT findings are present.     

Segmental infarction of the omentum secondary to torsion: ultrasound and computed tomography diagnosis

Segmental infarction of the omentum is a rare clinical entity that is seldom considered in the differential diagnosis for acute abdominal pain, especially as the clinical findings are so non-specific. Consequently, the diagnosis is usually made intraoperatively. The two cases presented here demonstrate the characteristic appearance of omental infarction on ultrasound and CT, which enables preoperative diagnosis. Preoperative radiological diagnosis may prevent unnecessary surgery.     

Improving the false-negative rate of CT in acute appendicitis—Reassessment of CT images by body imaging radiologists: A blinded prospective study

Purpose

To compare the accuracy of computed tomography (CT) analyzed by individual radiology staff members and body imaging radiologists in a non-academic teaching hospital for the diagnosis of acute appendicitis.

Patients and methods

In a prospective study 199 patients with suspected acute appendicitis were examined with unenhanced CT. CT images were pre-operatively analyzed by one of the 12 members of the radiology staff. In a later stage two body imaging radiologist reassessed all CT images without knowledge of the surgical findings and without knowledge of the primary CT diagnosis. The results, independently reported, were correlated with surgical and histopathologic findings.

Results

In 132 patients (66%) acute appendicitis was found at surgery, in 67 patients (34%) a normal appendix was found. The sensitivity of the primary CT analysis and of the reassessment was 76% and 88%, respectively; the specificity was 84% and 87%; the positive predictive value was 90% and 93%; the negative predictive value was 64% and 78%; and the accuracy was 78% and 87%.

Conclusion

Reassessment of CT images for acute appendicitis by body imaging radiologists results in a significant improvement of sensitivity, negative predictive value and accuracy. To prevent false-negative interpretation of CT images in acute appendicitis the expertise of the attending radiologist should be considered.     

CT evaluation of appendicitis and its complications: imaging techniques and key diagnostic findings

OBJECTIVE: This article reviews various CT protocols for appendicitis, identifies key CT findings for diagnosing appendicitis, discusses unusual manifestations such as chronic and recurrent appendicitis, and profiles imaging features that differentiate appendicitis from other inflammatory and neoplastic ileocecal conditions. Patients were studied with helical CT. CONCLUSION: CT is a highly accurate, noninvasive test for appendicitis, but the optimal CT technique is controversial. Major complications of appendicitis (perforation, abscess formation, peritonitis, bowel obstruction, septic seeding of mesenteric vessels, gangrenous appendicitis) and their management are discussed. Abdominal CT is a well-established technique in the study of acute abdominal pain and has shown high sensitivity and specificity for diagnosing and differentiating appendicitis, providing an accurate diagnosis in the early stages of disease.     

MDCT of acute cecal conditions

The cecum comprises a relatively short segment of the gastrointestinal tract, but it can be affected by numerous acute conditions. Acute conditions may arise from processes primary to the cecum, such as volvulus, bascule, neoplasm, and trauma. Alternatively, acute conditions can be due to secondary to systemic or nearby pathology, such as infection, inflammatory processes, ischemia, and infarction. While it is common to suspect appendicitis as the etiology of acute right lower quadrant abdominal pain, the cecum should also be considered as a potential cause of pain, especially in the setting of an abnormal or absent appendix. Multi-detector computed tomography (MDCT) has evolved to become the best imaging modality to evaluate patients presenting with right lower quadrant abdominal pain or suspected acute cecal pathology. Strengths of MDCT include rapid acquisition of images, high spatial resolution, and ability to create multi-planar reconstructed images. In this pictorial review, we illustrate and describe key MDCT findings for various acute cecal conditions with which the emergency radiologist should be familiar.