Pregnancy and appendicitis: a systematic review and meta-analysis on the clinical use of MRI in diagnosis of appendicitis in pregnant women

Background

The aim of this systematic review and meta-analysis was to evaluate the clinical use of MRI for the evaluation of acute appendicitis during pregnancy.

Methods

The searches were conducted by two independent researchers (MK, MS) to find the relevant studies published from 1/1/2009 until end of 30/12/2018. We searched for published literature in the English language in MEDLINE via PubMed, EMBASETM via Ovid, The Cochrane Library, and Trip database. For literature published in other languages, we searched national databases (Magiran and SID), KoreaMed, and LILACS. The keywords used in the search strategy are Pregnancy [MeSH], Pregnant [MeSH] OR-Magnetic resonance imaging [MeSH] OR-Appendicitis [MeSH] OR-Ultrasound, [MeSH] OR, imaging, MRI [MeSH] OR"،" and Right lower quadrant pain [MeSH]. The risk of bias of every article was evaluated by using QUADAS-2. On the basis of the results from the 2 × 2 tables, pooled measures for sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curves (AUC) along with their 95% confidence intervals (CIs) were calculated using the DerSimonian Lair methodology.

Results

As many as 1164 studies were selected. After analyzing the correspondence of the studies with the required criteria, 19 studies were selected for the final review. For appendicitis in pregnancy, the MRI sensitivity was 91.8% at the 95% confidence interval of (95% CI 87.7-94.9%). At the confidence interval of 95%, the specificity was 97.9% (95% CI 0.97.2-100%). The risk of bias in the studies conducted was measured using the QUADAS-2 tool.

Conclusion

MRI has high sensitivity and specificity (91.8%, 97.9% respectively) for the diagnosis of acute appendicitis in pregnant patients with clinically suspected appendicitis. It is an excellent imaging technique in many instances, which does not expose a fetus, or the mother, to ionizing radiation, making it an excellent option for pregnant patients with suspected acute appendicitis.

A Systematic Review and Meta-Analysis of Diagnostic Performance of MRI for Evaluation of Acute Appendicitis

OBJECTIVE

A meta-analysis was performed to determine the accuracy of MRI in the diagnosis of acute appendicitis in the general population and in subsets of pregnant patients and children.

MATERIALS AND METHODS

A systematic search of the PubMed and EMBASE databases for articles published through the end of October 2014 was performed to identify studies that used MRI to evaluate patients suspected of having acute appendicitis. Pooled data for sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

A total of 30 studies that comprised 2665 patients were reviewed. The sensitivity and specificity of MRI for the diagnosis of acute appendicitis are 96% (95% CI, 95-97%) and 96% (95% CI, 95-97%), respectively. In a subgroup of studies that focused solely on pregnant patients, the sensitivity and specificity of MRI were 94% (95% CI, 87-98%) and 97% (95% CI, 96-98%), respectively, whereas in studies that focused on children, sensitivity and specificity were found to be 96% (95% CI, 95-97%) and 96% (95% CI, 94-98%), respectively.

CONCLUSION

MRI has a high accuracy for the diagnosis of acute appendicitis, for a wide range of patients, and may be acceptable for use as a first-line diagnostic test.

Calprotectin could be a potential biomarker for acute appendicitis

BACKGROUND

Acute appendicitis is a common cause for a visit to the emergency department and appendectomy represents the most common emergency procedure in surgery. The rate of negative appendectomy however has remained high despite modern diagnostic apparatus. Therefore, there is need for a better preoperative screening of patients with suspected appendicitis. Calprotectin represents a predominant protein in the cytosol of neutrophil granulocytes and has been extensively investigated with regard to bowel pathologies. This study investigates the expression of calprotectin in the lumen of the vermiform appendix of patients undergoing appendectomy for suspected appendicitis.

METHODS

Appendix specimens from patients undergoing emergency appendectomy for suspected acute appendicitis were examined. Acute appendicitis was confirmed on histopathology. The qualitative expression of calprotectin in the vermiform appendix specimens was analyzed using specific calprotectin antibodies.

RESULTS

Vermiform appendix specimens from 52 patients (22 female and 30 male) including 11 with uncomplicated and 41 with complicated appendicitis were analyzed. Strong immunostainings were achieved with calprotectin antibody in the lumen of all specimens irrespective of the extent of appendicitis. Immunostaining was negative in the uninflamed appendix.

CONCLUSIONS

High calprotectin activity could be demonstrated within the lumen of vermiform appendix specimens following appendectomy for acute appendicitis. The high luminal accumulation of calprotectin-carrying cells could be interpreted as an invitation to study the expression of calprotectin in stool as a new diagnostic aid in patients with suspected appendicitis.

The current utility of ultrasound in the diagnosis of acute appendicitis

The purpose of this study is to evaluate the current performance of ultrasound in the diagnosis of acute appendicitis. Retrospectively, patients who presented to a single institution between 2011 and 2012 were included. Diagnostic accuracy was calculated, with surgery considered gold-standard. Our data demonstrates that US relative to surgery-confirmed appendicitis has a sensitivity and specificity of 48.4% and 97.9%, respectively. The diagnostic accuracy was further increased when there was a low pre-test probability, with a NPV of up to 96.6%. Ultrasound has a strong PPV in the diagnosis of acute appendicitis, and in equivocal cases, the NPV is reliable.

Acute Appendicitis: Use of Clinical and CT Findings for Modeling Hospital Resource Utilization

OBJECTIVE

The purpose of this study was to retrospectively investigate associations between baseline CT findings in suspected acute appendicitis and subsequent hospital resource utilization.

MATERIALS AND METHODS

One hundred thirty-eight patients (76 male and 62 female patients; mean [± SD] age, 40 ± 21 years) who were admitted for suspected acute appendicitis and underwent baseline CT were included. A single radiologist reviewed CT examinations for appendiceal-related findings. Linear and logistic regressions were performed to identify independent predictors of payer and hospital resource utilization. Combined performance of identified independent factors for predicting outcomes was determined.

RESULTS

Greater age, lower Charlson comorbidity index (CCI), lesser appendiceal wall thickness, absence of loculated fluid collection, and absence of periappendiceal fluid were significant independent predictors of inpatient surgery (joint sensitivity, 92.7%; specificity, 65.8%). Smaller appendiceal diameter, absence of periappendiceal fluid, and laparoscopic surgery were significant independent predictors of same-day discharge (joint sensitivity, 79.1%; specificity, 64.2%). Greater CCI, greater wall thickness, and presence of periappendiceal fluid were significant independent predictors of repeat abdominopelvic CT (joint sensitivity, 82.5%; specificity, 68.1%). Presence of an appendicolith was the only significant predictor of repeat emergency department visit within 30 days (sensitivity, 61.2%; specificity, 68.8%) and the only significant predictor of repeat inpatient admission within 30 days (sensitivity, 63.6%; specificity, 68.5%). Greater appendiceal diameter and presence of free air were significant predictors of inpatient costs, and predicted costs were as follows: $8047 + ($745 × appendiceal diameter) if free air was absent; and $-39,261 + ($4426 × appendiceal diameter) if free air was present. However, costs were poorly predicted when greater than $45,000. Sex, WBC count, and payer category were not independent predictors, relative to CT findings, of any outcome.

CONCLUSION

Admission CT findings serve as independent predictors of hospital resource utilization in suspected acute appendicitis.

How to evaluate appendices with borderline diameters on CT: proposal of a quick solution to overcome the limitations of the established CT criteria

RATIONALE AND OBJECTIVES

To propose a useful computed tomography (CT) criterion, the diameter with compression (DWC), especially in appendices with borderline diameters.

MATERIALS AND METHODS

We retrospectively collected 216 patients with visible appendices on CT after clinicopathologic confirmation of appendicitis. Each CT criterion of appendicitis was evaluated by an experienced abdominal radiologist: maximal outer diameter (MOD), DWC, mural thickness and enhancement, periappendiceal infiltration, and appendicolith. DWC is the expected diameter after deduction of the intraluminal compressible contents such as air and feces. All the CT criteria were compared in the appendicitis and nonappendicitis group.

RESULTS

The areas under the receiver operating characteristic curve (AUC) of the MOD and the DWC were 0.967 and 0.973, respectively. The optimal cutoff value was 8.2 mm for the MOD and 6.6 mm for the DWC. Twenty-five of the 80 appendicitis patients (31.2%) and 62 of the 136 nonappendicitis patients (45.6%) had MODs between 5.7 mm and 9.8 mm in the overlap between the two groups. In this overlap, the AUC of the MODs declined sharply to 0.767, whereas the AUC of the DWCs remained 0.923. Use of the criterion of DWC >6.6 mm yielded a sensitivity of 84.0%, a specificity of 88.7%, and an accuracy of 87.4%. There were no other criteria with both sensitivity and specificity >80% in the range of overlap.

CONCLUSIONS

The proposed CT criterion of the DWC is not affected by normal distension or periappendiceal inflammation but only by true appendicitis. Therefore, DWC can improve the diagnostic performance of appendicitis regardless of the MOD.

Acute appendicitis in children: ultrasound and CT findings in negative appendectomy cases

BACKGROUND

To decrease the negative appendectomy rate in children, knowledge of the misleading imaging findings on US and CT in negative appendicitis cases is important.

OBJECTIVE

To evaluate the negative appendectomy rate and describe the imaging findings of US and CT that lead radiologists to misdiagnose acute appendicitis in children.

MATERIALS AND METHODS

From 2007 to 2013, 374 children operated for suspected appendicitis were proved to either have acute appendicitis (n = 348) or to be negative for appendicitis (n = 26) on pathological reports. Negative appendectomy rates were compared among imaging modalities, age groups and genders. We retrospectively reviewed US and CT findings from negative appendectomy cases.

RESULTS

The overall negative appendectomy rate was 7.0% (26/374). There were no statistically significant differences among the subgroups. The most common misleading presentations on US were sonographic tenderness (9/16, 56%) and non-compressibility (9/16, 56%). The most common misleading finding on CT were the presence of an appendicolith or hyperdense feces (5/12, 42%). Periappendiceal fat inflammation was observed in only one case of negative appendicitis on US and on CT.

CONCLUSION

Radiologists can misdiagnose children with equivocal diameters of appendices as having acute appendicitis when sonographic tenderness or non-compressibility is present on US and when an appendicolith or hyperdense feces is noted on CT. The possibility of negative appendicitis should be borne in mind when periappendiceal fat inflammation is absent or minimal in indeterminate cases.

Validation of the diagnostic score for acute lower abdominal pain in women of reproductive age

Background. The differential diagnoses of acute appendicitis obstetrics, and gynecological conditions (OB-GYNc) or nonspecific abdominal pain in young adult females with lower abdominal pain are clinically challenging. The present study aimed to validate the recently developed clinical score for the diagnosis of acute lower abdominal pain in female of reproductive age. Method. Medical records of reproductive age women (15-50 years) who were admitted for acute lower abdominal pain were collected. Validation data were obtained from patients admitted during a different period from the development data. Result. There were 302 patients in the validation cohort. For appendicitis, the score had a sensitivity of 91.9%, a specificity of 79.0%, and a positive likelihood ratio of 4.39. The sensitivity, specificity, and positive likelihood ratio in diagnosis of OB-GYNc were 73.0%, 91.6%, and 8.73, respectively. The areas under the receiver operating curves (ROC), the positive likelihood ratios, for appendicitis and OB-GYNc in the validation data were not significantly different from the development data, implying similar performances. Conclusion. The clinical score developed for the diagnosis of acute lower abdominal pain in female of reproductive age may be applied to guide differential diagnoses in these patients.

Negative Appendectomy: an Audit of Resident-Performed Surgery. How Can Its Incidence Be Minimized?

Negative appendectomy remains a concern in current surgical practice. Data from the developing world is scarce. Data of appendectomies during the last 5 years were analyzed. Interval and incidental appendectomies were excluded. The demographic details, presenting complaints, clinical signs, and investigations performed were recorded in a predesigned proforma. The data were critically analyzed. Six hundred eighty-five appendectomies were performed during the period. One hundred eighty-five patients with a normal appendix were identified on histopathology. Sixty-seven patients with incidental or interval appendectomies were excluded. Thus, 118 patients had appendectomies performed erroneously. All these patients with presumed diagnosis of acute appendicitis were operated on by resident surgeons. Records of 17 patients could not be retrieved. The most common symptom was abdominal pain (100 %), and the commonest sign was right iliac fossa tenderness (93 %). Most of the patients underwent USG to supplement the diagnosis. CT scan and diagnostic laparoscopy were not performed. The negative appendectomy rate was 17.2 % (12.4 % in males; 33.3 % in females). The highest incidence of negative appendectomy was in females aged 11-20 years (66.7 %). The rate of negative appendectomy at our institute is comparable with the world statistics. More diligence is required in making the clinical diagnosis of acute appendicitis, especially in young females. The use of C-reactive protein and CT scan may decrease the negative appendectomy rate.

Improvement in the diagnosis of appendicitis

Our attempts to systematically improve accuracy in the evaluation of patients with suspected appendicitis are, in some ways, hindered by the fact that the condition is so frequently straightforward to diagnose. Careful history-taking and physical examination are reliable in most patients. However, establishing the diagnosis with these skills alone remains vulnerable to conditions that masquerade as acute appendicitis. A substantial body of clinical research over the last quarter-century has shown that improved accuracy is possible. Strategies for improvement include the use of diagnostic scoring systems, laboratory makers such as CRP, diagnostic laparoscopy, and advanced imaging modalities such as CT, MRI, and US. How clinicians use these strategies depends on many factors related to practice setting, the population served, and clinical goals. In children, for instance, the desire to limit exposure to ionizing radiation competes with the greater anatomic detail that a CT scan can provide; at the same time, many hospitals that treat children do not have the resources to maintain the sort of full-time, highly sophisticated abdominal US programs that achieve the highest rates of diagnostic accuracy in clinical studies. Trade-offs have to be made, but improvement is possible in almost all groups of patients: the clinical community should no longer settle for a 15% NA rate when 5% is clearly possible without adverse consequences. Many clinicians will be faced with the task of evaluating patients suspected of having acute appendicitis. A deliberate, proactive, and, ideally, benchmarked strategy for improving diagnosis should be the standard to which we hold ourselves and the promise we deliver to our patients.

Do you need a computed tomographic scan to evaluate suspected appendicitis in young men: an administrative database review

BACKGROUND

The purpose of this study was to evaluate the impact of computed tomographic (CT) scans of the abdomen on clinical outcomes and costs in young male patients presenting with suspected appendicitis.

METHODS

Discharge data from the University HealthSystem Consortium was accessed for all male patients between 18 and 55 years of age from October 2007 to June 2011.

RESULTS

Of a total of 13,228 patients who met the inclusion criteria, 11,340 (85%) were assessed using a CT scan of the abdomen, whereas 1,888 (15%) did not undergo CT evaluation. Patients undergoing CT imaging compared with those without a CT scan had less morbidity (.86% vs 2.2%, P < .0001) and fewer 30-day readmissions (1.8% vs 5.13%, P < .0001). However, CT imaging resulted in a higher overall length of hospital stay and a higher total cost.

CONCLUSIONS

This study suggests that in young men with suspected appendicitis, the use of an abdominal CT scan is associated with improved immediate postoperative complications, lower readmission rates with observed higher length of stay, and increased cost of care.

ACR Appropriateness Criteria® right lower quadrant pain--suspected appendicitis

The diagnostic imaging of patients presenting with right lower quadrant pain and suspected appendicitis may be organized according to age and gender and to the presence or absence of "classic" signs and symptoms of acute appendicitis. Among adult patients presenting with clinical signs of acute appendicitis, the sensitivity and specificity of CT are greater than those of ultrasound, with improved performance when CT is performed with intravenous contrast. The use of rectal contrast has been associated with decreased time in the emergency department. Computed tomography has also been shown to reduce cost and negative appendectomy rates. Both CT and ultrasound are also effective in the identification of causes of right lower quadrant pain unrelated to appendicitis. Among pediatric patients, the sensitivity and specificity of graded-compression ultrasound can approach those of CT, without the use of ionizing radiation. Performing MRI after inconclusive ultrasound in pregnant patients has been associated with sensitivity and specificity of 80% to 86% and 97% to 99%, respectively. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

The negative appendectomy rate: who benefits from preoperative CT?

OBJECTIVE

The purpose of this article is to determine the negative appendectomy rates of patients who did and did not undergo preoperative CT and to determine, more specifically, whether men benefit from preoperative CT.

MATERIALS AND METHODS

We identified 512 patients who had a nonincidental appendectomy between July 1, 2002, and June 30, 2007. Pathology records were compared with a radiology records search to determine which patients underwent preoperative CT. Proportions of patients were compared between groups using the Fisher exact test.

RESULTS

Of 512 patients who had a nonincidental appendectomy, 465 (91%) underwent preoperative CT, and 47 (9%) underwent appendectomy only on the basis of clinical findings. Overall, 22 of 465 patients (4.7%) who underwent preoperative CT had a negative appendectomy compared with six of 47 patients who did not undergo preoperative imaging (negative appendectomy rate, 12.7%; p = 0.03). Among men, six of 237 (2.5%) with preoperative CT had a negative appendectomy, versus five of 42 without imaging (negative appendectomy rate, 11.9%; p = 0.01).

CONCLUSION

The negative appendectomy rate was decreased for adult patients who underwent preoperative CT compared with patients who did not undergo preoperative imaging. Although most prior studies have suggested that CT is efficacious only in decreasing the negative appendectomy rate among women, we found that men benefit from CT as well.

Incidental Findings on Computed Tomography Scans for Acute Appendicitis: Prevalence, Costs, and Outcome

CT scan is increasingly being used to diagnose appendicitis due to its specificity and literature suggesting its cost-effectiveness. CT scans are associated with incidental findings. We sought to investigate the rates of incidental findings identified on CT scans, the follow-up of these findings, and the added cost associated with this follow-up. A retrospective review of patients who underwent appendectomies for acute appendicitis between 2003 and 2005 was completed at Elmhurst Hospital Center (Elmhurst, NY). Incidental findings were grouped into low and high significance, based on workup or follow-up needed. The diagnostic workup and cost of each incidental finding was ascertained. For patients who did not receive a workup due to lack of follow-up, an estimate of the minimum workup was calculated. Of 1142 patients with acute appendicitis, 876 (77%) had a CT scan. This rate increased over time (from 66% in 2003 to 85% in 2005, P < 0.01) and with age (70% in patients under 20 and 98% in patients over 50, P < 0.001). Incidental findings were common and increased with age (23% in the youngest group vs 78% in patients older than 50, P < 0.001). The cost associated with workup of these incidental findings increased with age as well. The increased use of CT scans is associated with a high rate of incidental findings. These findings are usually of low clinical significance but may require further workup and follow-up. Physicians need to be aware of the high rate of incidental findings, the need for further workup, and the associated costs.

Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT

OBJECTIVES

To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT.

METHODS

Ultrasound was performed upon admission in 183 consecutive adult patients (111 women, 72 men, mean age 32) with suspicion of acute appendicitis and a BMI between 18.5 and 30 (step 1). No further examination was recommended when ultrasound was positive for appendicitis, negative with low clinical suspicion, or demonstrated an alternative diagnosis. All other patients underwent LDCT (30 mAs) (step 2). Standard intravenously enhanced CT (180 mAs) was performed after indeterminate LDCT (step 3).

RESULTS

No further imaging was recommended after ultrasound in 84 (46%) patients; LDCT was obtained in 99 (54%). LDCT was positive or negative for appendicitis in 81 (82%) of these 99 patients, indeterminate in 18 (18%) who underwent standard CT. Eighty-six (47%) of the 183 patients had a surgically proven appendicitis. The sensitivity and specificity of the algorithm were 98.8% and 96.9%.

CONCLUSIONS

The proposed algorithm achieved high sensitivity and specificity for detection of acute appendicitis, while reducing the need for standard CT and thus limiting exposition to radiation and to intravenous contrast media.

Making the diagnosis of acute appendicitis: do more preoperative CT scans mean fewer negative appendectomies? A 10-year study

PURPOSE

To determine the frequency of preoperative computed tomography (CT) in the evaluation of patients suspected of having appendicitis at one institution during the past 10 years and to determine whether changes in CT utilization were associated with changes in the negative appendectomy rate.

MATERIALS AND METHODS

Institutional review board approval was obtained, and a waiver of informed consent was granted for this HIPAA-compliant study. A surgical database search yielded medical record numbers of 925 patients (526 [ 56.9%] men and 399 [43.1%] women; mean age, 38 years (range, 18-95 years]) who underwent urgent appendectomy between January 1998 and September 2007. Patients who were younger than 18 years of age at the time of surgery were excluded. CT, pathology, and surgery reports were reviewed. By using logistic regression, changes in the proportion of patients undergoing CT and in the proportion of patients undergoing each year appendectomy in which the appendix was healthy were evaluated. Subgroup analyses based on patient age (<or= 45 years or > 45 years) and sex also were performed.

RESULTS

Prior to urgent appendectomy, 18.5% of patients underwent preoperative CT in 1998 compared with 93.2% of patients in 2007. The negative appendectomy rate for women 45 years of age and younger decreased from 42.9% in 1998% to 7.1% in 2007. However, the timing of the decline in negative appendectomy rates for women 45 years and younger could not be proved to be associated with the increase in CT use. There was no significant trend toward a lower negative appendectomy rate for men regardless of age or for women older than 45 years of age with increased use of preoperative CT. The shift from single-detector CT to multidetector CT and the use of decreasing section thickness also correlated with a reduction in false-positive diagnoses.

CONCLUSION

Rising utilization of preoperative CT and advances in technology coincided with a decrease in the negative appendectomy rate for women 45 years and younger but not in men of any age or women older than 45 years.

Defining the current negative appendectomy rate: for whom is preoperative computed tomography making an impact?

BACKGROUND

Historically, the negative appendectomy rate (NAR) for patients operated on for acute appendicitis (AA) has exceeded 20%. We sought to define the current NAR with increased use of computed tomography (CT) and laparoscopy.

METHODS

Records of 1425 consecutive patients undergoing appendectomy for suspicion of AA during the past 7 years at a single institution were reviewed. The NAR was calculated and compared with earlier data from this institution (1995-1999). Statistical methods included the Fisher exact test and the Student t test; differences of P < .05 were considered statistically significant.

RESULTS

The overall NAR was 7.65% compared to 16.3% over the period 1995-1999 (P = .0001), without a change in the perforation rate. Concurrently, the rate of preoperative CT increased from 32% to 95%. CT was associated with a lesser NAR only among adult females (7.6% vs 20.8%, P = .005) but not among adult males or children. No difference in NAR was noted in comparing laparoscopic and open appendectomy. Patients without AA had a greater mean duration of symptoms and lower white blood cell count at presentation than those with AA. Most patients undergoing negative appendectomy had a CT, and more than 50% had CT interpretations that were positive for, or could not exclude, AA.

CONCLUSIONS

The NAR in our hospital has decreased progressively to approximately 5%. Although preoperative CT is used in almost all patients, it is only associated with a lesser NAR among adult females. False-positive CTs may contribute to the residual NAR, and further data are needed to determine whether subgroups of male or pediatric patients benefit from preoperative CT.

CT scan in patients with suspected appendicitis: clinical implications for the acute care surgeon

OBJECTIVE

To determine the influence of computed tomography (CT) scans on diagnosis and management of patients with suspected appendicitis.

METHODS

Retrospective 2-year review of 1,630 patients with suspected appendicitis, categorized into three groups based on the likelihood (Alvarado scores) of having appendicitis. Group 1: low likelihood (Alvarado score < or =4); group 2: intermediate likelihood (Alvarado scores 5-7), and group 3: high likelihood (Alvarado score > or = 8). CT scan utilization, hospital course, and final pathology were retrospectively reviewed.

RESULTS

More patients received a CT scan in 2006 as compared with 2005 (60 vs. 52%; p = 0.001). The overall appendectomy rate was similar between the 2 years (57% in 2005 vs. 57% in 2006; p = 0.995). The overall appendectomy rate in patients with a CT was significantly higher as compared with those without (60 vs. 53%; p = 0.002). The appendectomy rate in patients with Alvarado scores < or =4 and no CT scan was significantly lower than in those with a CT scan (12 vs. 48%; p < 0.0001). The overall negative appendectomy rate in patients with a CT scan was similar to that in those without: 31/546 (6%) vs. 23/383 (6%).

CONCLUSIONS

CT scan utilization increased the appendectomy rate only in patients with a low clinical suspicion for appendicitis. Preoperative CT scans did not decrease the negative appendectomy rate.