Appendiceal Wall Enhancement Research Articles

Impact of an appendicolith and its characteristics on the severity of acute appendicitis.

Antibiotics have been reported as an efficient and safe treatment option for uncomplicated acute appendicitis without an appendicolith diagnosed using computed tomography (CT). The aim of this study was to assess the association of a CT-diagnosed appendicolith and its characteristics with appendicitis severity. A large prospective patient cohort with suspected acute appendicitis enrolled between April 2017 and November 2018 was retrospectively reviewed. The initial analysis evaluated the association of a CT-diagnosed appendicolith with complicated acute appendicitis; then, based on the availability of CT images, a subset of patients was analysed for the correlation of appendicolith characteristics with appendicitis severity. The final appendicitis assessment (uncomplicated or complicated-including perforation, gangrene, an abscess, or a tumour) was determined for all patients. Out of 3512 eligible patients, 3085 patients with appendicitis were selected and 380 patients with an appendicolith and with a CT image available for reassessment were included. Out of the 3085 patients with CT-diagnosed acute appendicitis, 1101 (35.7%) patients presented with both acute appendicitis and an appendicolith and, out of these, 519 (47.1%) had complicated acute appendicitis. In the patients without an appendicolith (1984 patients), 426 (21.5%) had complicated appendicitis (P < 0.001). Re-evaluation of CT images for 380 patients showed that a larger appendicolith diameter (OR = 1.15 (95% c.i. 1.06 to 1.25); P < 0.001), appendicolith location at the base of the appendix (55.1% versus 44.9%; P = 0.008), and heterogeneous appendiceal wall enhancement around the appendicolith (68.4% versus 31.6%; P < 0.001) were associated with an increased risk of complicated acute appendicitis. The presence of an appendicolith in patients with acute appendicitis is correlated with the risk of complicated appendicitis. This risk is further increased by a larger appendicolith diameter or appendicolith location at the base of the appendix.

Computed Tomography Findings Associated with Treatment Failure after Antibiotic Therapy for Acute Appendicitis.

ObjectiveTo identify the CT findings associated with treatment failure after antibiotic therapy for acute appendicitis.Materials and MethodsAltogether, 198 patients who received antibiotic therapy for appendicitis were identified by searching the hospital's surgery database. Selection criteria for antibiotic therapy were uncomplicated appendicitis with an appendiceal diameter equal to or less than 11 mm. The 86 patients included in the study were divided into a treatment success group and a treatment failure group. Treatment failure was defined as a resistance to antibiotic therapy or recurrent appendicitis during a 1-year follow-up period. Two radiologists independently evaluated the following CT findings: appendix–location, involved extent, maximal diameter, thickness, wall enhancement, focal wall defect, periappendiceal fat infiltration, and so on. For the quantitative analysis, two readers independently measured the CT values at the least attenuated wall of the appendix by drawing a round region of interest on the enhanced CT (HUpost) and non-enhanced CT (HUpre). The degree of appendiceal wall enhancement (HUsub) was calculated as the subtracted value between HUpost and HUpre. A logistic regression analysis was used to identify the CT findings associated with treatment failure.ResultsSixty-four of 86 (74.4%) patients were successfully treated with antibiotic therapy, with treatment failure occurring in the remaining 22 (25.5%). The treatment failure group showed a higher frequency of hypoenhancement of the appendiceal wall than the success group (31.8% vs. 7.8%; p = 0.005). Upon quantitative analysis, both HUpost (46.7 ± 21.3 HU vs. 58.9 ± 22.0 HU; p = 0.027) and HUsub (26.9 ± 17.3 HU vs. 35.4 ± 16.6 HU; p = 0.042) values were significantly lower in the treatment failure group than in the success group.ConclusionHypoenhancement of the appendiceal wall was significantly associated with treatment failure after antibiotic therapy for acute appendicitis.

Can appendix bending angle be an additional finding to detect acute appendicitis on MDCT?

Aim: Computed tomography (CT) is frequently used as an imaging modality in the evaluation of acute appendicitis. The most frequently used measurement to detect acute appendicitis is maximal outer diameter of appendix on CT and several studies have reported other CT findings of acute appendicitis, such as thickness of the appendiceal wall, appendiceal wall enhancement, peri-appendiceal free fluid, peri-appendiceal inflammation, peri-appendiceal lymph node, appendicolith and cecal wall thickening. We investigated the value of the appendix bending angle (ABA) as an additional and novel finding in the diagnosis of acute appendicitis. Methods: This retrospective study was conducted after the local ethics committee’s approval. 52 consecutive patients who underwent appendectomies were assigned to the study group. The patients, who underwent abdominopelvic CT for any other reason than acute abdomen, were included as control group. Results: The mean age of the appendicitis group was 41.9±16.0; male predominance was present (n=32, 61.5%). Peri-appendiceal inflammation was seen in 65.4%, peri-appendiceal lymph node was seen in 73.1% and appendicolith was present in 9.6% of the appendicitis group. The mean ABA was 103.0±15.9 degree in study group and 118.8±23,8 degree in control group respectively (p&amp;lt;0.001). The sensitivity of ABA was calculated as 76.9% and the specificity was 58.3% at 113.15 degree which is the best cut-off point calculated by ROC curve. There was no appendicitis over 142.3 degrees. Conclusion: ABA can be used as an additional finding which is decreased in acute appendicitis.

Systematic Review and Meta-Analysis of CT Features for Differentiating Complicated and Uncomplicated Appendicitis.

Purpose To perform a systematic review and meta-analysis to identify computed tomographic (CT) features for differentiating complicated appendicitis in patients suspected of having appendicitis and to summarize their diagnostic accuracy. Materials and Methods Studies on diagnostic accuracy of CT features for differentiating complicated appendicitis (perforated or gangrenous appendicitis) in patients suspected of having appendicitis were searched in Ovid-MEDLINE, EMBASE, and the Cochrane Library. Overlapping descriptors used in different studies to denote the same image finding were subsumed under a single CT feature. Pooled diagnostic accuracy of the CT features was calculated by using a bivariate random effects model. CT features with pooled diagnostic odds ratios with 95% confidence intervals not including 1 were considered as informative. Results Twenty-three studies were included, and 184 overlapping descriptors for various CT findings were subsumed under 14 features. Of these, 10 features were informative for complicated appendicitis. There was a general tendency for these features to show relatively high specificity but low sensitivity. Extraluminal appendicolith, abscess, appendiceal wall enhancement defect, extraluminal air, ileus, periappendiceal fluid collection, ascites, intraluminal air, and intraluminal appendicolith showed pooled specificity greater than 70% (range, 74%-100%), but sensitivity was limited (range, 14%-59%). Periappendiceal fat stranding was the only feature that showed high sensitivity (94%; 95% confidence interval: 86%, 98%) but low specificity (40%; 95% confidence interval, 23%, 60%). Conclusion Ten informative CT features for differentiating complicated appendicitis were identified in this study, nine of which showed high specificity, but low sensitivity. © RSNA, 2017 Online supplemental material is available for this article.

IMAGE FINDINGS AND THE ADDED VALUE OF CT SCAN IN THE DIAGNOSIS OF ACUTE APPENDICITIS

Background: Appendicitis is one of the most common causes of acute abdominal pain, requiring surgical treatment. The problem of how to make an early and accurate diagnosis of acute appendicitis should be prioritized. Aims: To describe the image findings and evaluate the added value of CT scan in the diagnosis of acute appendicitis. Materials and Method: 121 patients were admitted to Hue University Hospital with suspicion of having acute appendicitis from April 2016 to July 2017. There would be a complementary CT scan if the ultrasonography result was inconclusive or irrelevant to clinical manifestations. The results of ultrasonography and CT scan were then correlated with surgical findings and treatment. Results: 39.7% of 121 patients with suspicion of acute appendicitis needed a complementary CT scan after ultrasonography had been performed. CT scan also detected 19 alternative diagnoses that caused acute abdominal pain. The direct signs of acute appendicitis on CT scan with high sensitivity were enlarged appendix with over 6mm in diameter (93.8%), appendiceal wall thickening (87.5%), appendiceal wall enhancement (90.6%); the signs with high specificity were maximum depth of intraluminal appendiceal fluid greater than 2,6mm (100%), appendiceal wall enhancement (87.5%) and appendicolith (87.5%). Among indirect signs of acute appendicitis on CT scan, the sign with the highest sensitivity and specificity was periappendiceal fat stranding (90.6% and 100% respectively). The sensitivity, specificity and accuracy of CT scan in diagnosis of acute appendicitis were 90.6%, 100% and 93.8% in that order. The sensitivity, specificity and accuracy of the diagnosis pathway using primary ultrasonography and complementary CT scan was 97.1%, 94.1% and 96.7%. Conclusion: The signs of acute appendicitis on CT scan with high sensitivity were enlarged appendix with over 6mm in diameter, periappendiceal fat stranding, appendiceal wall thickening and enhancement. The signs of acute appendicitis on CT scan with high specificity were periappendiceal fat stranding, maximum depth of intraluminal appendiceal fluid greater than 2.6mm, appendiceal wall enhancement and appendicolith. The diagnosis pathway using primary ultrasonography and complementary CT scan yielded a high diagnostic sensitivity, specificity and accuracy for acute appendicitis. Key words: Acute appendicitis, complementary CT scan

Value of Us in Patients with Equivocal CT Findings of Acute Appendicitis: Comparison with CT Reassessment

To compare diagnostic values of ultrasound (US) and CT reassessment in patients with equivocal CT findings of acute appendicitis, including those with coexistent inflammatory lesion. Patients with equivocal CT findings of acute appendicitis (n=115), who underwent US, were included. Two abdominal radiologists reviewed CT scans independently. They analyzed four CT findings (appendiceal wall enhancement, appendiceal wall thickening, intraluminal air in appendix, and coexistent inflammation) and make a diagnosis of acute appendicitis. Patients were categorized into positive and negative appendicitis based on previous US reports. The diagnostic performance, interobserver agreement in CT findings interpretation, and appendicitis likelihood were calculated. The area under the receiver operator characteristic curve (AUC, 0.960), sensitivity (100%), and specificity (92.1%) of US was higher than those of CT reassessment (reviewer 1: 0.697, 51.9% and 87.5%; reviewer 2: 0.759, 66.7% and 85.2%, respectively). In the coexistent inflammation group, the AUC (0.990), sensitivity (100%), and specificity (98.0%) of US were higher than those of CT reassessment (reviewer 1: 0.607, 27.3% and 94.1%, reviewer 2: 0.561, 14.3% and 98.0%%, respectively). Interobserver agreement in the CT diagnosis of appendicitis was moderate (κ=0.44). In patients with equivocal CT findings of acute appendicitis, US shows better diagnostic performance compared to CT reassessment, and helps differentiate between acute appendicitis and periappendicitis.

Predictive Factors to Distinguish Between Patients With Noncomplicated Appendicitis and Those With Complicated Appendicitis.

PurposeRecently, randomized controlled trials have reported that conservative therapy can be a treatment option in patients with noncomplicated appendicitis. However, preoperative diagnosis of noncomplicated appendicitis is difficult. In this study, we determined predictive factors to distinguish patients with noncomplicated appendicitis from those with complicated appendicitis.MethodsA total of 351 patients who underwent surgical treatment for acute appendicitis from January 2011 to December 2012 were included in this study. We classified patients into noncomplicated or complicated appendicitis groups based on the findings of abdominal computed tomography and pathology. We performed a retrospective analysis to find factors that could be used to discriminate between noncomplicated and complicated appendicitis.ResultsThe mean age of the patients in the complicated appendicitis group (54.5 years) was higher than that of the patients in the noncomplicated appendicitis group (40.2 years) (P < 0.001), but the male-to-female ratios were similar. In the univariate analysis, the appendicocecal junction's diameter, appendiceal maximal diameter, appendiceal wall enhancement, periappendiceal fat infiltration, ascites, abscesses, neutrophil proportion, C-reactive protein (CRP), aspartate aminotransferase, and total bilirubin were statistically significant factors. However, in the multivariate analysis, the appendiceal maximal diameter (P = 0.018; odds ratio [OR], 1.129), periappendiceal fat infiltration (P = 0.025; OR, 5.778), ascites (P = 0.038; OR, 2.902), and CRP (P < 0.001; OR, 1.368) were statistically significant.ConclusionSeveral factors can be used to distinguish between noncomplicated and complicated appendicitis. Using these factors, we could more accurately distinguish patients with noncomplicated appendicitis from those with complicated appendicitis.

Differentiation of early perforated from nonperforated appendicitis: MDCT findings, MDCT diagnostic performance, and clinical outcome

To determine the CT findings and assess their diagnostic performance in differentiating early perforated appendicitis from nonperforated appendicitis, and to compare therapeutic approaches and clinical outcomes between two types of appendicitis. Our retrospective study was approved by our institutional review board and informed consent was waived. From July 2012 to July 2013, 339 patients [mean age 40.8 years; age range 19-80 years; 183 male (mean age 40.5 years; age range 19-79 years) and 156 female (mean age 41.2 years; age range 19-80 years)] who underwent appendectomy with preoperative CT examination for suspected acute appendicitis were included, with exclusion of 37 patients with specific CT findings for advanced perforated appendicitis. And they were categorized into nonperforated and early perforated appendicitis groups according to surgical and pathologic reports. The following CT findings were evaluated by two radiologists blinded to pathologic and surgical findings: transverse diameter of the appendix, thickness of the appendiceal wall, the depth of intraluminal appendiceal fluid, appendiceal wall enhancement, presence or absence of focal defect in the appendiceal wall, intraluminal appendiceal air, appendicolith/fecalith, periappendiceal changes, cecal wall thickening, and free fluid. The type of surgical procedures, performance of surgical drainage, and the length of hospital stay were recorded. Univariate and multivariate logistic regression analysis were used to determine the CT findings for differentiating early perforated appendicitis from nonperforated appendicitis, a total of 75 (22%) of the 339 patients was diagnosed with early perforated appendicitis. Focal wall defect [adjusted odds ratio (aOR), 23.40; p < 0.001], circumferential periappendiceal changes (aOR, 5.63; p < 0.001), appendicoliths/fecaliths (aOR, 2.47; p = 0.015), and transverse diameter of the appendix (aOR, 1.22; p = 0.003) were independently differentiating variables for early perforated appendicitis. The transverse diameter of the appendix (≥11 mm) had the highest sensitivity (62.7%) and focal wall defect in the appendiceal wall showed the highest specificity (98.8%). The prevalence of surgical drainage was higher (p = 0.001) and the mean hospital stay was approximately one day longer (p < 0.001) in the early perforated group than nonperforated group. CT can be helpful in differentiating early perforated appendicitis from nonperforated appendicitis, although the sensitivity of the evaluated findings was somewhat limited.

Maximum Outer Appendiceal Diameter as a Criterion of Acute Appendicitis: Evaluation at Computerized Tomography

Objective The goal of this study was to assess the optimum diagnostic cutoff value of maximum outer appendiceal diameter on computed tomography (CT) images in patients with suspected acute appendicitis in the emergency department. Methods A total of 328 patients with clinical suspicion of appendicitis were retrospectively reviewed. Evaluation of CT images, and chart review for clinical, laboratory, surgical, and pathologic findings were performed. Logistic regression was used to identify possible predictive factors influencing diagnosis of acute appendicitis. The receiver operating characteristic (ROC) curve was applied to determine the most suitable diagnostic cutoff value of appendiceal diameter for acute appendicitis. Results In a total of 136 patients (41.5%) the diagnosis of acute appendicitis was made; 192 patients (58.5%) had nonacute appendicitis. Mean appendiceal diameter was 12.68 ± 3.31 mm in patients with acute appendicitis and 6.01 ± 1.50 mm in patients without. The appendiceal diameter had a significantly statistical difference to differentiate the presence from the absence of acute appendicitis with an area under the ROC curve of 0.985 (95% confidence interval, 0.973–0.996). An appendiceal diameter cutoff value of 8.15 mm had a sensitivity of 97%, a specificity of 93.2%, and an accuracy of 94.8%. Appendiceal wall enhancement with intravenous contrast medium also had a significantly statistical difference for discriminating patients with acute appendicitis from those without by logistic regression. Conclusion Detection of maximum outer appendiceal diameter and appendiceal wall enhancement with intravenous contrast medium on CT could help differentiate patients with acute appendicitis from those without. An appendiceal diameter greater than 8.15 mm is particularly useful for diagnosis of acute appendicitis.

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

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. 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. 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 < 0.05). Areas under the curves of reviewers 1 and 2 significantly increased from 0.516 and 0.706 to 0.677 and 0.841, respectively, when reviewers were told which CT variables were significant (P = 0.0193 and P = 0.0397, respectively). Knowledge of the identified CT findings was found to improve diagnostic accuracy for acute appendicitis in patients with equivocal CT findings. • 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.

Evaluation of the Maximum Depth of Intraluminal Appendiceal Fluid to Diagnose Appendicitis With a 64–Detector Row CT Scanner

The objective of this study was to investigate whether the criterion "maximum depth of intraluminal appendiceal fluid greater than 2.6 mm" ("DEPTH >2.6 mm"), with the use of 64-detector row computed tomography, is useful to diagnose appendicitis. We retrospectively evaluated 0.68-mm-thick images of 2894 intravenously enhanced abdominal-pelvic computed tomography using the following criteria: (1) appendiceal wall thickness greater than 3 mm, (2) appendiceal wall enhancement, (3) focal cecal wall thickening, (4) adjacent lymphadenopathy greater than 5 mm, (5) appendicolith, (6) periappendiceal inflammation, and (7) the new criterion, DEPTH >2.6 mm. Of the 2894 images, 1013 were classified into normal group (including 622 distended [diameter >6 mm] but normal appendices without adjacent lesions), modified group (235 distended normal appendices modified with adjacent lesions), proven-appendicitis group (82 operatively proven appendicitis cases), and clinical-appendicitis group (62 clinically certified appendicitis cases). The new criterion, DEPTH >2.6 mm, demonstrated both higher sensitivities and higher specificities in all groups (>90%), although this criterion showed lower specificities than some conventional criteria. In contrast, conventional criteria showed lower sensitivities or lower specificities (<60%) in one or more of these groups. DEPTH >2.6 mm is particularly useful for differentiating appendicitis from distended normal appendix.

Computed Tomography Criterion for the Diagnosis of Appendicitis Without Periappendiceal Inflammation in Children Using the Maximum Depth of Intraluminal Appendiceal Fluid

The objective of this study was to evaluate whether maximum depth of intraluminal appendiceal fluid (DEPTH) is useful in differentiating appendicitis without periappendiceal inflammation from enlarged normal appendices in children. We retrospectively evaluated 826 intravenously enhanced abdominal-pelvic computed tomographic examinations in children (aged 0-18 years) using the following criteria for appendicitis: (1) appendiceal wall thickness greater than 3 mm, (2) appendiceal wall enhancement, (3) focal cecal wall thickening, (4) adjacent adenopathy, (5) appendicolith, and (6) DEPTH. Of 826, 192 were classified into the noncomplicated-normal appendix group (85 enlarged normal appendices [diameter >6 mm] without adjacent lesions), the complicated-normal appendix group (44 enlarged normal appendices with adjacent lesions), or the our-appendicitis group (63 operatively proved appendicitis without periappendiceal inflammation). The criterion "DEPTH greater than 2.6 mm" determined by receiver operating characteristic analysis between our-appendicitis and complicated-normal appendix groups demonstrated both higher sensitivity and higher specificity in all groups (>90%). In contrast, the other criteria showed lower sensitivities (<58%) in our-appendicitis group. The criterion "DEPTH greater than 2.6 mm" is particularly useful for differentiating appendicitis without periappendiceal inflammation from enlarged normal appendices in children.

Crohn’s disease: multi-detector row CT-enteroclysis appearance of the appendix

The objective of our retrospective study was to determine the MDCT-enteroclysis appearance of the appendix in patients with Crohn's disease and to correlate this appearance with the status of the disease. We reviewed the MDCT-enteroclysis examinations of 76 patients with Crohn's disease. Images were analyzed for visualization of the appendix, largest axial diameter of the appendix and degrees of enhancement. Findings were correlated with the status of the disease (active vs. nonactive) and compared with those observed in a control group. Among the various variables, hyperenhancement of the appendiceal wall was found in 18.9% of patients with active disease and in no patients with inactive disease nor in the control group (P = 0.0023). This sign had a specificity of 100% for differentiating between active and inactive Crohn's disease. We conclude that increased appendiceal wall enhancement is, at a statistically significant level, more frequently observed in patients with active Crohn's disease by comparison with patients with inactive disease and control subjects. This result suggests that this finding may be used as an additional MDCT-enteroclysis finding to determine the activity of the disease.

New CT Criterion for Acute Appendicitis: Maximum Depth of Intraluminal Appendiceal Fluid

The purpose of this study was to evaluate whether a new criterion-maximum depth of the intraluminal appendiceal fluid-is useful to differentiate between a normal appendix with diameter greater than 6 mm and appendicitis without periappendiceal inflammation. The study included 59 patients showing a normal appendix with diameter greater than 6 mm and having no adjacent lesions (noncomplicated-normal-appendix group), 30 patients showing a normal appendix with diameter greater than 6 mm and having adjacent lesions (complicated-normal-appendix group), and 38 patients showing appendicitis without periappendiceal inflammation (appendicitis group). The following specific CT findings were retrospectively evaluated: maximum appendiceal diameter greater than 6 mm, maximum appendiceal wall thickness greater than 3 mm, appendiceal wall enhancement, focal cecal wall thickening, adjacent adenopathy, appendicolith, and maximum depth of the intraluminal appendiceal fluid. The mean maximum depth of the intraluminal appendiceal fluid in the appendicitis group was significantly higher than in the two groups with a normal appendix (Mann-Whitney U test: p < 0.001). When using maximum depth of the intraluminal appendiceal fluid greater than 2.6 mm for a criterion of appendicitis, sensitivity and specificity for differentiation between the appendicitis group and the other two groups with a normal appendix were both greater than 80%. In contrast, when using another CT a criterion, either sensitivity or specificity was 50% or less. The new CT criterion based on the maximum depth of the intraluminal appendiceal fluid greater than 2.6 mm is particularly useful for differentiating appendicitis without periappendiceal inflammation from a normal appendix with a diameter greater than 6 mm.

The value of contrast-enhanced helical CT scan with rectal contrast enema in the diagnosis of acute appendicitis

Background: The aim of this retrospective study is to assess the accuracy of single slice helical CT scan with intravenous, and rectal contrast (CTRC) in the diagnosis of acute appendicitis (AA) in patients with suspected AA, with particular analysis of the diagnostic signs. Participants and methods: Abdomino–pelvic helical CTRC was performed on 75 consecutive patients with suspicion of AA. Radiologic diagnosis was compared with surgical/pathologic results and clinical follow-up. In addition, the CTRC examinations were retrospectively reviewed independently by two experienced radiologists using predefined diagnostic criteria. The sensitivity, specificity, and frequency of each diagnostic sign were calculated. The interobserver agreement and the statistical significance of the frequency for each diagnostic criterion were assessed using the Kappa and Fisher tests, respectively. Results: The accuracy of helical CTRC in the diagnosis of AA was 94.7%, sensitivity 100%, specificity 90%, PPV 89.7%, and the NPV 100%. Wall enhancement and nonopacification of the appendix recorded the highest sensitivity and specificity (97% and 100%, 94% and 95%, respectively). Appendiceal thickness greater than 6 mm was present in 100% of true-positive cases. However, 26.5% of true-negative cases had also an appendiceal diameter exceeding 6 mm, a value used as a cut-off for normal appendiceal diameter. The highest interobserver agreement was recorded for appendiceal wall enhancement and for nonopacification of the appendix ( K=0.97 and 0.88, respectively). Conclusions: CTRC is an accurate and relatively fast technique for investigation of patients with suspected AA. A negative CTRC can exclude completely the diagnosis of AA. Nonopacification of the appendix and appendiceal wall enhancement are highly sensitive, specific, and reproducible, signs representing major criteria for the diagnosis of AA.

Evaluation of perforated and nonperforated appendicitis with CT

Fifty-three patients with 38 cases of perforated appendicitis and 15 cases of appendicitis without perforation were evaluated based on the computed tomography (CT) appearances of appendiceal diameter, phlegmon, abscess, extraluminal air, appendiceal wall enhancement, lateroconal fascial thickening, appendicolith, bowel wall thickening, ascites, ileal wall enhancement, peritoneal enhancement, periappendiceal fluid, omental haziness, retrocecal appendix, intraluminal air, and the combination of intraluminal air and appendicolith. The result of appendiceal diameter was compared using two-sample Student's t test, and the other CT findings were analyzed by Fisher's Exact Test. Our results showed that appendix was larger in caliber in perforated appendix ( P<.05). Direct CT signs (i.e., phlegmon, abscess, and extraluminal air) were more specific for perforated appendicitis ( P<.05). Indirect signs (bowel wall thickening, ascites, ileal wall enhancement, intraluminal air, and combined intraluminal air and appendicolith) were also found in higher incidence in appendiceal perforation ( P<.05). Appendiceal enlargement and ileal wall enhancement were the two predominant findings in one case of perforation. We concluded that direct and indirect CT appearances can differentiate appendicitis with and without perforation. Indirect signs may be helpful in difficult case.

The most useful findings for diagnosing acute appendicitis on contrast-enhanced helical CT.

To evaluate the most useful findings to look for in diagnosing acute appendicitis on contrast-enhanced helical CT. Appendiceal helical CT scans with intravenous contrast administration (abdomen, 7-mm collimation; abdominopelvic junction, 5-mm collimation) of 71 patients with surgically proven acute appendicitis and 167 patients with alternative diagnoses were reviewed retrospectively. Three radiologists analyzed the following parameters: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), appendiceal intraluminal air, intramural air, extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, segmental terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The features that best distinguished appendicitis from alternative diagnoses were selected with stepwise logistic regression analysis. Nine CT findings distinguished acute appendicitis from alternative diagnoses (P < 0.05): enlarged appendix (R = 0.739), appendiceal wall thickening (R = 0.525), periappendiceal fat stranding (R = 0.414), appendiceal wall enhancement (R = 0.404), focal cecal apical thickening (R = 0.171), appendicolith(s) (R = 0.157), extraluminal air (R = 0.050), intramural air (R = 0.043), and phlegmon (R = 0.030). Enlarged appendix (sensitivity, 93%; specificity, 92%), appendiceal wall thickening (sensitivity, 66%; specificity, 96%), periappendiceal fat stranding (sensitivity, 87%; specificity, 74%), and appendiceal wall enhancement (sensitivity, 75%; specificity, 85%) showed the statistically most significant association with acute appendicitis. On 5-mm-section contrast-enhanced helical CT examinations, enlarged appendix, appendiceal wall thickening, periappendiceal fat stranding, and appendiceal wall enhancement were the most useful findings for diagnosing acute appendicitis.

The Most Useful Findings for Diagnosing Acute Appendicitis on Contrast-Enhanced Helical Ct

To evaluate the most useful findings to look for in diagnosing acute appendicitis on contrast-enhanced helical CT. Appendiceal helical CT scans with intravenous contrast administration (abdomen, 7-mm collimation; abdominopelvic junction, 5-mm collimation) of 71 patients with surgically proven acute appendicitis and 167 patients with alternative diagnoses were reviewed retrospectively. Three radiologists analyzed the following parameters: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), appendiceal intraluminal air, intramural air, extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, segmental terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The features that best distinguished appendicitis from alternative diagnoses were selected with stepwise logistic regression analysis. Nine CT findings distinguished acute appendicitis from alternative diagnoses (P < 0.05): enlarged appendix (R = 0.739), appendiceal wall thickening (R = 0.525), periappendiceal fat stranding (R = 0.414), appendiceal wall enhancement (R = 0.404), focal cecal apical thickening (R = 0.171), appendicolith(s) (R = 0.157), extraluminal air (R = 0.050), intramural air (R = 0.043), and phlegmon (R = 0.030). Enlarged appendix (sensitivity, 93%; specificity, 92%), appendiceal wall thickening (sensitivity, 66%; specificity, 96%), periappendiceal fat stranding (sensitivity, 87%; specificity, 74%), and appendiceal wall enhancement (sensitivity, 75%; specificity, 85%) showed the statistically most significant association with acute appendicitis. On 5-mm-section contrast-enhanced helical CT examinations, enlarged appendix, appendiceal wall thickening, periappendiceal fat stranding, and appendiceal wall enhancement were the most useful findings for diagnosing acute appendicitis.

Acute Appendicitis: Sensitivity, Specificity and Diagnostic Accuracy of Thin-Section Contrast-Enhanced CT Findings

Purpose: To assess the sensitivity, specificity, and diagnostic accuracy of individual contrast-enhanced helical CT findings of acute appendicitis. Materials and Methods: We retrospectively reviewed the appendiceal helical CT scans, obtained after intravenous contrast administration (abdomen; 7-mm collimation, abdominopelvic junction; 5-mm collimation), of 50 patients with surgically proven acute appendicitis and 112 with alternative diagnoses. The following parameters were analysed by three radiologists: enlarged appendix (> 6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), (appendiceal) intraluminal air, (appendiceal) intraluminal air extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. Results: The CT findings of acute appendicitis that statistically distinguished it from alternative diagnoses were an enlarged appendix (sensitivity; 92%, specificity; 93%, diagnostic accuracy; 93%), appendiceal wall thickening (for these three parameters: 68%, 96% and 88%, respectively), periappendiceal fat stranding (90%, 79%, 82%), appendiceal wall enhancement (72%, 86%, 82%), appendicolith (16%, 100%, 74%), and focal cecal apical thickening (14%, 100%, 74%) (for each, p