MRI vs. ultrasound for suspected appendicitis during pregnancy

PURPOSE: To compare the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasound (US) and MRI in evaluation of pregnant patients with a clinical suspicion of appendicitis. MATERIALS AND METHODS: A total of 33 pregnant patients with suspected appendicitis underwent US and MRI. The original imaging reports generated at the time of presentation were used for data analysis. Pathology reports were used for disease confirmation in patients who underwent appendectomy. When surgery was not performed, a medical record review was performed. The sensitivity, specificity, PPV, and NPV were calculated for US and MRI in the diagnosis of appendicitis. RESULTS: Five of the 33 patients had pathologically-proven appendicitis. Four of the five patients with appendicitis were correctly diagnosed at MRI while one was interpreted as indeterminate (appendix not seen). At US, one was correctly diagnosed, one was incorrectly diagnosed as normal, and three were interpreted as indeterminate (appendix not seen). In 13 patients, a normal appendix was diagnosed at MRI, none of whom had appendicitis. In three patients, a normal appendix was diagnosed at US, one of whom had appendicitis. When the appendix was visualized at MRI, the sensitivity, specificity, PPV, and NPV for the diagnosis of appendicitis was 100% for all parameters. When the appendix was visualized at US, the sensitivity, specificity, PPV, and NPV for the diagnosis of appendicitis was 50%, 100%, 100%, and 66%, respectively. CONCLUSION: Based on a relatively small number of true-positives, our data suggests that MRI is very useful for the diagnosis and exclusion of appendicitis in pregnant women.     

Reassessment of CT images to improve diagnostic accuracy in patients with suspected acute appendicitis and an equivocal preoperative CT interpretation

Objectives

To identify CT features that discriminate individuals with and without acute appendicitis in patients with equivocal CT findings, and to assess whether knowledge of these findings improves diagnostic accuracy.

Methods

53 patients that underwent appendectomy with an indeterminate preoperative CT interpretation were selected and allocated to an acute appendicitis group or a non-appendicitis group. The 53 CT examinations were reviewed by two radiologists in consensus to identify CT findings that could aid in the discrimination of those with and without appendicitis. In addition, two additional radiologists were then requested to evaluate independently the 53 CT examinations using a 4-point scale, both before and after being informed of the potentially discriminating criteria.

Results

CT findings found to be significantly different in the two groups were; the presence of appendiceal wall enhancement, intraluminal air in appendix, a coexistent inflammatory lesion, and appendiceal wall thickening (P?P?=?0.0193 and P?=?0.0397, respectively).

Conclusions

Knowledge of the identified CT findings was found to improve diagnostic accuracy for acute appendicitis in patients with equivocal CT findings.

Key Points

? Numerous patients with clinically equivocal appendicitis do not have acute appendicitis ? Computed tomography (CT) helps to reduce the negative appendectomy rate ? CT is not always infallible and may also demonstrate indeterminate findings ? However knowledge of significant CT variables can further reduce negative appendectomy rate ? An equivocal CT interpretation of appendicitis should be reassessed with this knowledge     

Diagnostic imaging of suspected appendicitis in pregnant women: comparison of CT to ultrasonography

Purpose: To compare the sensitivity and specificity of CT versus ultrasonography for the diagnosis of appendicitis in a population of pregnant women. Materials and methods: Radiology records (1988–1999) were searched for results of examinations performed on pregnant patients with suspected appendicitis. Subjects included only women with known intrauterine pregnancies. Thirty-two pregnant women were identified who had been studied by CT, ultrasound, or both. Ten patients had undergone focused abdominal CT with colon contrast, while 29 had undergone abdominal or pelvic ultrasonography with attention to the appendix. Results were compared to surgical pathology or follow-up findings. Results: CT sensitivity was 100 %, specificity 100 %, positive predictive value (PPV) 100 %, negative predictive value (NPV) 100 % and accuracy was 100 %. Ultrasound sensitivity was 100 %, specificity 83 %, PPV 50 %, NPV 100 %, and accuracy 21 %. Conclusion: In this small cohort of gravid females with suspected appendicitis, the sensitivity of focused abdominal CT with colon contrast was equal to that in the nonpregnant patient. In contradistinction to this, abdominal ultrasonography was frequently indeterminate. We hypothesize that ultrasonography is less accurate due to body habitus and the variable location of the appendix during pregnancy.     

Helical CT imaging of clinically suspected appendicitis: correlation of CT and histological findings

PURPOSE: The diagnosis of appendicitis is traditionally made on the basis of clinical findings supported by laboratory results. The aim of our study was to determine the accuracy and feasibility of using a relatively new technique of computed tomography (CT) using only colonic contrast medium. MATERIALS AND METHODS: A total of 50 patients clinically diagnosed as having appendicitis were prospectively examined before surgery with thin-collimation helical CT from the L3 level to the acetabular roof with only rectally administered colon contrast medium. The hard copy CT images were reviewed jointly by two radiologists and a consensus was reached for each patient. The results were then compared with the surgical and histological findings at appendicectomy. RESULTS: There were 35 true-positives, one false-positive, 12 true-negatives and two false-negatives for CT. This yielded an accuracy of 94%, sensitivity of 95%, specificity of 92%, positive predictive value of 97% and negative predictive value of 86%. The appendix was identified in 45 patients (90%) and obscured by an inflammatory mass in the remaining five. An alternative diagnosis was found in 10 of 12 normal CT examinations (83%). CONCLUSION: Helical CT with rectal contrast medium is a quick, well tolerated and accurate test to diagnose appendicitis. It can offer alternative, possibly non-surgical diagnosis in patients who would otherwise have undergone laparotomy.     

Added value of ultrasound re-evaluation for patients with equivocal CT findings of acute appendicitis: a preliminary study

Purpose

To prospectively estimate the additional diagnostic value of ultrasound (US) re-evaluation for patients with equivocal computed tomography (CT) findings of acute appendicitis.

Methods

Between April 2011 and October 2011, 869 consecutive patients with suspected appendicitis who were referred for CT were included. The likelihood of appendicitis was prospectively categorized into five categories. US re-evaluation was recommended for patients in the ‘equivocal appendix’ and ‘probably not appendicitis’ groups. The overall negative appendectomy rate during the study period was compared with the rate of the previous year, and negative appendectomy rates of the US and non-US evaluation groups were also compared.

Results

Among 869 patients, 71 (8.2 %) had equivocal appendicitis findings and 63 (7.2 %) were diagnosed as probably not appendicitis. The sensitivity and specificity of CT combined with US re-evaluation group (100 % and 98.1 %, respectively) exceeded those of the CT alone group (93 % and 99 %; equivocal group considered as negative appendicitis, 100 % and 89.9 %; as positive, respectively, P?<?0.0001). After adding US re-evaluation, the overall negative appendectomy rate in our institution decreased from 3.4 to 2.3 %.

Conclusion

For patients with equivocal CT findings of acute appendicitis, US re-evaluation can improve diagnostic accuracy and decrease the rate of negative appendectomies.

Key Points

? Misdiagnosis of appendicitis still occurs, especially in patients with equivocal radiological findings. ? The sensitivity and specificity of CT followed by US exceeded those of CT alone. ? After US re-evaluation, the negative appendectomy rate decreased from 3.4 to 2.3?%. ? US re-evaluation in equivocal cases helps diagnostic confidence and further management.     

怀疑阑尾炎CT检查的其他诊断

目的评价临床工作中因怀疑急性阑尾炎而进行CT检查的成人中的其他诊断。材料与方法本回顾性研究符合HIPAA要求,得到单位伦理委员会的批准,无需知情同意书。连续性回顾2006年1月—2009年12月期间因怀疑急性阑尾炎就诊于同一学术医疗机构急诊科和急救室的1571例成年病人。由具执业资质的放射科医师对腹盆CT做出诊断,并综合临床、手术、病理和其他影像学发现做出最终诊断。采用Fisher精确检验和Mann-Whitney检验进行统计分析,以双尾P值<0.05为差异有统计学意义。结果 1571例中867例(55.2%)在CT检查中得出特异性诊断。371例(23.6%)倾向于急性阑尾炎,496例(31.6%)被诊断为阑尾炎以外的其他疾病。在获得阑尾炎以外其他CT诊断的496例病人中,204例(41.1%)进行了住院治疗,109例(22.0%)由于非阑尾炎原因而进行了手术或影像导向的介入治疗;而在CT检查没有做出特异性诊断的病人中,住院和外科治疗的比例分别为14.1%和4.4%(P<0.0001)。最常见的疾病种类包括阑尾以外的胃肠道疾病(46.0%)、妇科疾病(21.6%)、泌尿生殖系统疾病(16.9%)和肝胆胰疾病(7.7%)。结论对于临床怀疑急性阑尾炎的成人,腹盆CT常可以发现引起症状的其他原因,这些疾病常需住院和手术治疗。     

Incidence of acute appendicitis in patients with equivocal CT findings

OBJECTIVE: The purpose of our study was to determine the incidence of acute appendicitis in patients for whom the CT interpretation is deemed equivocal. MATERIALS AND METHODS: Of 1,344 patients referred for CT with suspected appendicitis between January 1998 and December 2002, 172 patients were identified in whom the radiographic findings were equivocal. Two radiologists reviewed the equivocal CT cases, reassessing appendiceal size and the presence of right lower quadrant stranding, fluid, or an appendicolith. The reviewers' findings were correlated with surgical pathology reports and clinical follow-up. RESULTS: Fifty-three (31%) of 172 patients with indeterminate findings on CT scans were subsequently diagnosed with appendicitis. For reviewers 1 and 2, respectively, appendicitis was present in five (14%) of 36 and six (13%) of 47 patients who had isolated appendiceal diameter less than 9 mm, and in 11 (52%) of 21 and in 10 (50%) of 20 patients who had isolated appendiceal dilatation equal to or greater than 9 mm. If a normal diameter appendix (< 6 mm) was visualized in a patient who had right lower quadrant stranding or fluid, appendicitis was present in only one (17%) of six and in four (27%) of 15 patients for reviewers 1 and 2, respectively. If the appendix could not be identified but there was right lower quadrant stranding or fluid, appendicitis was present in seven (37%) of 19 and in eight (53%) of 15 patients. CONCLUSION: Appendicitis is encountered in about 30% of patients with equivocal findings on CT, and the diagnosis should be considered in most of these patients if they are appropriately symptomatic. However, when the appendix measures less than 9 mm alone, the likelihood of appendicitis is much smaller.     

The impact of ultrasound in suspected acute appendicitis

AIMS: To evaluate prospectively the impact of an appendix ultrasound (US) service on the clinical management of patients presenting with suspected acute appendicitis. MATERIALS AND METHODS: The referring clinician completed a proforma for patients presenting with suspected acute appendicitis. Two visual analogue scales assessed clinical suspicion before and after knowledge of laboratory results. The clinician also indicated if they intended to operate had US been unavailable. During a 3-year period, 327 patients were examined by graded-compression US and diagnosed "positive" or "negative" for acute appendicitis. Findings were correlated with histopathology results. The referring clinician completed a retrospective audit questionnaire to assess user satisfaction. RESULTS: Clinical suspicion was altered by knowledge of laboratory results. The decision to operate if US had been unavailable, was "yes" in 70 cases (group A), "no" in 231 (group B), and incomplete in 26 (group C). In group A, 31 patients (44.3%) had a negative US and 25 avoided surgery. US identified 39 cases of appendicitis and 37 appendicectomies confirmed appendicitis in 34 cases. In group B, 72 (31.2%) patients had a positive US and 66 appendicectomies confirmed 51 cases of appendicitis. The sensitivity of US was 94.7% in group A, 93.3% in group B and 93.8% overall. Specificity was 90.6% in group A, 91.2% in group B and 91.3% overall. US findings were contrary to intended surgical management in 103 cases. Management was altered in 97 cases (32.2%), with a positive outcome in 85 (28.2%). The referrers found US of appendix very useful in planning appropriate management. CONCLUSION: US of the appendix increases diagnostic accuracy, alters management and is more sensitive and specific than clinical impression, either alone, or in conjunction with laboratory results.     

Case based simulation in MRI for suspected appendicitis in children

PurposeTo establish the effect on diagnostic confidence of a simulation setting, in which radiologists re-interpret anonymized pediatric MRI cases.MaterialsIn this IRB-approved study, participants completed surveys rating confidence before and after interpreting 10 MRI cases for suspected appendicitis in children.Results18 radiologists (4 faculty, 5 fellows, and 9 residents) correctly identified an average of 7.44 cases (range 5–9). Self-described confidence regarding technique and interpretation increased from 2.0 (SD 0.77) and 2.33 (SD 0.69) to 2.83 (SD 0.71) and 2.94 (SD 0.73), respectively.ConclusionSimulated interpretation of pediatric MRI in suspected appendicitis results in increased self-describe confidence without requiring additional capital/equipment expenses.     

Impact of MRI to clear the cervical spine after a negative CT for suspected spine trauma

Emergency Radiology - To describe the clinical presentation of trauma patients receiving a negative cervical spine MRI (CSMRI) after cervical spine CT (CSCT) without acute findings and calculate...     

Neutrophil-specific 99mTc-labeled anti-CD15 monoclonal antibody imaging for diagnosis of equivocal appendicitis.

We evaluated 99mTc-labeled anti-CD15 immunoglobulin M monoclonal antibody (LeuTech) for diagnosing acute appendicitis in patients with an equivocal clinical presentation. LeuTech avidly binds to circulating and sequestered human polymorphonuclear neutrophils in vivo, eliminating in vitro cell labeling and blood handling. METHODS: We studied 49 patients to evaluate the safety and efficacy of LeuTech imaging. 99mTc-labeled LeuTech was prepared on site using a lyophilized kit, 99mTc-labeled pertechnetate, and 2 different incubation techniques, 1 at room temperature and the other at 37 degrees C. The abdomen was serially imaged for up to 3 h after the intravenous administration of 370-740 MBq 99mTc-labeled LeuTech. Scans were read as positive or negative for acute appendicitis or other intraabdominal infection. The institutional diagnosis was established by surgery, other diagnostic studies, or 1-mo clinical follow-up. RESULTS: Scans were positive for appendicitis in all 26 patients with appendicitis, for a sensitivity of 100%, and negative for appendicitis in 19 of 23 patients without appendicitis, for a specificity of 83%. Accuracy, positive predictive value, and negative predictive value were 92%, 87%, and 100%, respectively. Results were not different between the LeuTech preparations. The rate of laparotomies with negative findings in patients who underwent surgery was 10%. The average time from injection to LeuTech visualization in the appendix for cases positive for appendicitis was 9 min. No serious adverse reactions occurred. CONCLUSION: LeuTech imaging is safe, rapid, and sensitive for diagnosis of appendicitis in equivocal cases. The potential advantages of LeuTech over currently available radiopharmaceuticals for infection imaging are ease of preparation, absence of blood handling, excellent image quality, no requirement for SPECT, and rapid diagnostic uptake.     

Evaluation of suspected appendicitis in children and young adults: helical CT

PURPOSE: To evaluate the accuracy of helical computed tomography (CT) for the diagnosis of appendicitis in children and to assess the utility of CT in establishing alternative diagnoses. MATERIALS AND METHODS: The medical records of 154 children (median age, 12 years; age range, 1-20 years) who were suspected to have appendicitis and who underwent CT were reviewed. The gastrointestinal tract was opacified in 151 of 154 patients: Only orally administered contrast material was used in 126 patients; only rectally administered contrast material, in 21 patients; and both oral and rectal contrast material, in four patients. CT findings were correlated with surgical and histopathologic findings or with clinical follow-up findings. RESULTS: Sixty-four CT scans were interpreted as positive for appendicitis and included 58 true-positive and six false-positive scans. Ninety scans were interpreted as negative and included 87 true-negative and three false-negative scans. CT had a sensitivity of 95% and a specificity of 94% for the diagnosis of appendicitis. In addition, in 32 (34%) of 93 patients without appendicitis, an alternative diagnosis was established on the basis of CT findings. CONCLUSION: Helical CT is useful in a pediatric population to diagnose or exclude appendicitis and to establish an alternative diagnosis.     

Diagnostic accuracy of focused appendiceal CT in clinically equivocal cases of acute appendicitis.

PURPOSE: To determine the diagnostic accuracy of modified focused appendiceal computed tomography (CT) to exclude or confirm appendicitis in patients who presented with equivocal symptoms and signs of appendicitis. MATERIALS AND METHODS: One hundred patients (age range, 14-81 years; mean age, 30.6 years) with equivocal symptoms and signs of acute appendicitis were included in this prospective study. Patients were given 30 mL of diatrizoate meglumine and diatrizoate sodium and 60 mL of sorbitol mixed in 1 L of water orally over 1 hour. CT was performed 1.5 hours after the commencement of oral contrast material administration. The criteria used for the diagnosis of appendicitis were (a) appendix greater than 6 mm in maximum diameter, (b) no contrast material in the appendiceal lumen, and (c) inflammatory changes in the periappendiceal fat. CT results were compared with histopathologic findings at appendectomy. Patients with negative CT findings were followed up by telephone or clinically. RESULTS: Of 100 cases, 30 were positive at CT and 70 were negative. There were 28 true-positive cases; two false-positive cases, one cecal diverticulitis and one pelvic peritonitis with periappendicitis; and two false-negative cases, one perforated appendix and one mucosal and submucosal inflammation of the appendix but no transmural inflammation. Sensitivity was 93%, specificity was 97%, and accuracy was 96%. CONCLUSION: Focused appendiceal CT in which oral contrast material is used alone yields high levels of accuracy in clinically equivocal cases of acute appendicitis.