Acute appendicitis remains one of the most frequent causes of acute abdominal pain requiring emergency surgical intervention worldwide. Despite being a common clinical entity, its diagnosis continues to pose challenges due to the wide spectrum of clinical presentations, particularly in children, elderly individuals, and females of reproductive age. The classical presentation periumbilical pain migrating to the right iliac fossa, anorexia, nausea, fever, and leukocytosis is not always present, which complicates timely diagnosis and may increase the risk of perforation, abscess, or peritonitis. Historically, clinicians relied solely on clinical judgment, which resulted in high negative appendectomy rates ranging from 15% to 30%. To address these limitations, several scoring systems and imaging modalities have been developed to support clinical decision-making. Among these tools, the Modified Alvarado Score (MAS) is one of the most widely applied clinical scoring systems. Developed as a simplified version of the Alvarado score, it incorporates key symptoms, signs, and basic laboratory parameters to stratify the likelihood of appendicitis. MAS is inexpensive, simple to use, and available even in resource-limited settings. A score ≥7 is generally considered strongly predictive of acute appendicitis, allowing surgeons to proceed with operative management with reasonable confidence. However, its diagnostic accuracy may vary across populations and healthcare contexts, and its clinical utility tends to decline in atypical cases. Ultrasonography (USG), a non-invasive, readily available, radiation-free imaging modality, has become an integral component in the evaluation of suspected appendicitis. It allows real-time visualization of appendiceal diameter, wall thickness, periappendiceal fat changes, and the presence of appendicolith, abscess, or free fluid. While its specificity is generally high, the diagnostic sensitivity of USG is often influenced by operator expertise, patient body habitus, bowel gas, and anatomical variations of the appendix. Nevertheless, USG serves as a valuable adjunct particularly in children, pregnant women, and cases with equivocal clinical findings. Histopathology remains the gold standard for confirming acute appendicitis. Comparing MAS and USG findings with histopathology therefore provides an objective way to evaluate the diagnostic performance of these tools. Recent studies have attempted to determine whether MAS alone, USG alone, or a combination of both yields superior diagnostic accuracy. While some reports highlight MAS as more sensitive and USG as more specific, others argue that integrating clinical scoring with imaging optimizes patient selection for surgery and reduces negative appendectomy rates. Given this ongoing debate, it becomes crucial to reassess the performance of both MAS and ultrasonography in different clinical settings. Aim To compare the diagnostic accuracy of the Modified Alvarado Score and ultrasonographic findings against histopathology in patients with suspected acute appendicitis. Objectives 1. To determine the diagnostic accuracy of the Modified Alvarado Score in predicting histopathology-confirmed acute appendicitis. 2. To determine the diagnostic accuracy of ultrasonographic findings in predicting histopathology-confirmed acute appendicitis. 3. To compare the sensitivity, specificity, PPV, and NPV of both modalities to identify which predicts acute appendicitis more accurately.

Source of Data Data were obtained from all patients presenting with symptoms and/or signs suggestive of acute appendicitis who underwent classical open appendectomy in the Department of General Surgery at a tertiary care hospital in Western Vidarbha. All relevant clinical, ultrasonographic, operative, and histopathological data were extracted and recorded. Study Design A diagnostic evaluation study was conducted to compare the Modified Alvarado Score and ultrasonographic findings with post-operative histopathological outcomes. Study Location The study was carried out in the Department of General Surgery, Government Medical College and Hospital, Akola, Maharashtra. Study Duration The study was conducted over a two-year period, from February 2023 to February 2025. Sample Size A total of 433 patients were included. The sample size was calculated using anticipated sensitivity and specificity values reported by previous studies (Nasiri et al.) with a 95% confidence interval and 16% precision, incorporating an expected dropout rate. Inclusion Criteria 1. Patients of all ages and both sexes presenting with symptoms and/or signs of acute appendicitis. 2. Patients who underwent classical open appendectomy. 3. Patients willing to provide informed consent. Exclusion Criteria 1. Patients initially suspected of appendicitis but ruled out before surgery. 2. Patients with gynecological or urological causes of abdominal pain. 3. Pregnant women. 4. Patients with abdominal mass or appendicular abscess. 5. Patients with intraoperatively confirmed ruptured appendix. Procedure and Methodology All eligible patients were initially resuscitated and stabilized. A detailed clinical history was obtained, emphasizing pain characteristics and prior similar episodes. Physical examination focused on classical signs: right iliac fossa tenderness, rebound tenderness, guarding, and fever. Routine laboratory investigations, including complete blood count, were performed. All patients underwent abdominal ultrasonography to evaluate appendiceal diameter, mural thickness, compressibility, presence of appendicolith, periappendiceal fat stranding, free fluid, or abscess. The Modified Alvarado Score was calculated for every patient using documented symptoms, signs, and leukocyte count. Ultrasonographic findings were independently recorded by trained radiologists. Based on clinical scoring and imaging interpretation, patients with high suspicion for acute appendicitis were taken up for open appendectomy. Intraoperative findings were noted, and the excised appendix was preserved in formalin and sent for histopathological examination. Histopathology reports served as the gold standard for confirming or excluding acute appendicitis. Sample Processing Appendectomy specimens were processed using standard histopathological techniques. Hematoxylin and eosin (H&E) staining was performed, and slides were independently examined for evidence of acute inflammation, transmural infiltration, gangrene, perforation, or other pathology. Statistical Methods Data were entered into Microsoft Excel and analyzed using SPSS software. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were calculated for both MAS and USG based on comparison with histopathology. Associations between variables were assessed using the Chi-square test, with p < 0.05 considered statistically significant. Confidence intervals were set at 95% Data Collection Demographic details, clinical features, Modified Alvarado Scores, ultrasonographic findings, operative notes, and histopathological results were systematically recorded in a structured proforma. All patients’ information was anonymized for confidentiality.

Table 1 presents the baseline comparison of the diagnostic performance of the Modified Alvarado Score (MAS) and ultrasonography (USG) against histopathological examination (HPE), which serves as the gold standard. Out of 433 patients, histopathology confirmed acute appendicitis in 378 cases (87.3%), a statistically significant proportion when compared with the expected prevalence of 80% (p = 0.001; 95% CI: 83.8-90.2). A Modified Alvarado Score of ≥7 was observed in 352 patients (81.3%), with a mean score of 7.8 ± 1.6, showing a strong association with histopathology-positive appendicitis (OR 4.62; p < 0.001). Ultrasonography suggested appendicitis in 324 patients (74.8%), with a mean sonographic appendiceal diameter of 8.9 ± 1.2 mm, and also demonstrated a significant correlation with histopathology results (OR 3.88; p < 0.001). When concordance between MAS and USG was evaluated, 298 patients (68.8%) showed agreement between both diagnostic tools and histopathology. Kappa statistics revealed substantial agreement (κ = 0.64), which was statistically significant (p = 0.002). Table 1: Baseline Diagnostic Comparison (MAS vs USG vs Histopathology) Variables Positive n (%) Negative n (%) Mean ± SD (where applicable) Test of Significance 95% CI p-value Histopathology-positive appendicitis 378 (87.3%) 55 (12.7%) One-sample Z vs expected 80% 83.8-90.2 0.001* Modified Alvarado Score ≥7 352 (81.3%) 81 (18.7%) MAS Mean = 7.8 ± 1.6 Chi-square vs HPE OR 4.62 <0.001* Ultrasonography suggestive of appendicitis 324 (74.8%) 109 (25.2%) Appendix diameter = 8.9 ± 1.2 mm Chi-square vs HPE OR 3.88 <0.001* Concordance between MAS & USG aligned with HPE 298 (68.8%) 135 (31.2%) Kappa agreement test κ = 0.64 0.002* Table 2: Accuracy of Modified Alvarado Score Alone MAS Category HPE Positive n (%) HPE Negative n (%) Test of Significance Sensitivity % Specificity % 95% CI p-value MAS ≥ 7 (True +) 328 (75.8%) 24 (5.5%) Chi-square = 82.4 86.7 56.4 81.2-90.8 <0.001* MAS < 7 (False -) 50 (11.6%) 31 (7.1%) Total MAS Prediction Accuracy 378/433 correct (87.3%) Diagnostic accuracy test 87.3% 84.1-90.1 0.001* PPV / NPV 93.2% / 38.2% McNemar test on discordance 0.004* Table 2 evaluates the diagnostic accuracy of the Modified Alvarado Score alone in predicting histopathology-confirmed acute appendicitis. Among patients with MAS ≥7, 328 (75.8%) were true positives, whereas only 24 (5.5%) represented false positives. The association between MAS category and histopathology positivity was statistically significant (χ² = 82.4; p < 0.001), with a high sensitivity of 86.7% and a moderate specificity of 56.4%. The 95% confidence interval for sensitivity ranged from 81.2% to 90.8%, supporting the robustness of the estimate. Patients with MAS <7 included 50 false negatives (11.6%) and 31 true negatives (7.1%). Overall, MAS correctly predicted the diagnosis in 378 of 433 cases, yielding an accuracy of 87.3% (p = 0.001; 95% CI: 84.1-90.1). The score demonstrated a high positive predictive value (PPV) of 93.2%, although the negative predictive value (NPV) was relatively low at 38.2%, suggesting that MAS is more effective at ruling in rather than ruling out appendicitis. McNemar’s test for discordance between MAS prediction and histopathology further confirmed statistical significance (p = 0.004). Table 3 analyzes the diagnostic performance of ultrasonography in identifying histopathology-confirmed appendicitis. USG was suggestive of appendicitis in 302 cases (69.7%) that were confirmed positive on histopathology, while only 22 cases (5.1%) were false positives. This association was statistically significant (χ² = 61.5; p < 0.001). Ultrasonography demonstrated a sensitivity of 79.9% and a specificity of 60.0%, with a 95% confidence interval for sensitivity ranging between 74.3% and 84.6%. Although USG missed 76 cases (17.6%) of true appendicitis (false negatives), its positive predictive value remained high at 93.2%, indicating reliability when USG findings are positive. However, the negative predictive value was low at 30.3%, suggesting limited utility in excluding acute appendicitis when the scan appears normal or equivocal. Overall diagnostic accuracy was 77.4% (95% CI: 73.1-81.1; p < 0.001). McNemar’s test again confirmed significant discordance with histopathology results (p = 0.006). Table 3: Accuracy of Ultrasonography Alone USG Findings HPE Positive n (%) HPE Negative n (%) Test of Significance Sensitivity % Specificity % 95% CI p-value USG Suggestive (True +) 302 (69.7%) 22 (5.1%) Chi-square = 61.5 79.9 60.0 74.3-84.6 <0.001* USG Normal / Equivocal (False -) 76 (17.6%) 33 (7.6%) Total USG Prediction Accuracy 335/433 correct (77.4%) Diagnostic accuracy test 77.4% 73.1-81.1 <0.001* PPV / NPV 93.2% / 30.3% McNemar test 0.006* Table 4: Direct Comparative Accuracy: MAS vs USG Parameter Modified Alvarado Score (MAS) Ultrasonography (USG) Statistical Comparison 95% CI of Difference p-value Sensitivity 86.7% 79.9% Z-difference = 2.31 2.1-11.4 0.021* Specificity 56.4% 60.0% Z-difference = 0.84 -3.5-9.3 0.401 (ns) PPV 93.2% 93.2% No difference 0.991 NPV 38.2% 30.3% Z-difference = 1.89 0.1-15.1 0.059 (borderline) Overall Diagnostic Accuracy 87.3% 77.4% Chi-square = 13.6 5.4-16.7 0.001* Table 4 directly compares the diagnostic metrics of the Modified Alvarado Score and ultrasonography to determine which modality provides superior predictive accuracy for acute appendicitis. MAS demonstrated a higher sensitivity (86.7%) than USG (79.9%), and this difference was statistically significant (Z = 2.31; p = 0.021; 95% CI: 2.1-11.4). Specificity was slightly higher for USG (60.0%) than MAS (56.4%), though the difference was not statistically significant (p = 0.401). Both modalities showed identical positive predictive values (93.2%), reflecting strong performance when predicting positive cases. The negative predictive value was higher for MAS (38.2%) compared to USG (30.3%), with borderline statistical significance (p = 0.059). Overall diagnostic accuracy was significantly greater for MAS (87.3%) compared to USG (77.4%), as supported by chi-square analysis (χ² = 13.6; p = 0.001; 95% CI difference: 5.4-16.7). Figure 1: ROC curve with AUC

Table 1 demonstrates that histopathology confirmed appendicitis in 87.3% of the cases, which is comparable to studies by Gongidi et al. (2014)[6], who reported an 85% confirmation rate among suspected appendicitis cases. The high prevalence in our cohort reflects the selective inclusion of patients with strong clinical suspicion. MAS ≥7 was observed in 81.3% of patients and demonstrated significant diagnostic association (OR 4.62), similar to findings from Nazir et al. (2018)[7], who showed that MAS remains a reliable clinical scoring method in predicting acute appendicitis. The mean MAS of 7.8 ± 1.6 in our study agrees with the results of Rehman et al. (2017)[8], who reported mean scores ranging between 7.2 and 8.0 among confirmed cases. Ultrasonography showed a positivity rate of 74.8% with significant correlation with histopathology (OR 3.88). This mirrors the diagnostic performance reported by Gaitan et al. (2016)[9], where USG positivity ranged from 70-76% in skilled hands. The appendix diameter of 8.9 ± 1.2 mm observed aligns with the classical threshold of >6 mm described by Rubin et al. (2019)[10]. Overall concordance between MAS and USG (κ = 0.64) reflects substantial agreement and complements findings from Bachur et al. (2012)[11], who emphasized the enhanced diagnostic accuracy when clinical scoring is combined with imaging. Table 2 strengthens the utility of MAS. The sensitivity of 86.7% and PPV of 93.2% recorded in our study are consistent with Nanjundaiah et al. (2014)[12], who demonstrated that MAS ≥7 has high sensitivity and positive predictive values in adults and adolescents. The moderate specificity (56.4%) and low NPV (38.2%) also align with published data, suggesting that while MAS is excellent in ruling in appendicitis, it is less effective for ruling it out. The overall prediction accuracy of 87.3% correlates well with observations made by Khan et al. (2017)[13], who reported accuracy between 85-90% for MAS. Table 3 evaluates ultrasonography independently. The sensitivity of 79.9% and specificity of 60.0% are consistent with the results from Gürleyik et al. (2015)[14], who found USG sensitivity ranging from 75-82% depending on the operator’s expertise. The high PPV (93.2%) and low NPV (30.3%) in the present study mirror the findings from Karul et al. (2013)[15], underscoring that a positive USG is reliable, but a negative scan does not exclude appendicitis, particularly in obese patients or those with retrocecal appendices. The overall diagnostic accuracy of 77.4% is comparable to USG performance in multiple meta-analyses. Table 4 provides direct comparison and reinforces MAS as the superior initial diagnostic tool. MAS had significantly higher sensitivity (86.7% vs. 79.9%; p = 0.021) and notably better overall diagnostic accuracy (87.3% vs. 77.4%; p = 0.001). These findings are in agreement with Flum et al. (2017)[16], who emphasized the robust performance of clinical scoring systems in early diagnosis. Although USG showed slightly better specificity, the difference was statistically insignificant, aligning with the comparative study by Terasawa et al. (2016)[17], which reported similar trends. The equal PPV (93.2%) for both modalities highlights that once MAS or USG is positive, the likelihood of true appendicitis is very high. The low NPV values for both tools further support the continued importance of combining clinical assessment, laboratory parameters, and imaging consistent with modern diagnostic recommendations. Overall, the findings of this study confirm the continuing relevance of MAS as a rapid, inexpensive, and reliable screening tool for acute appendicitis. Ultrasonography remains indispensable as a confirmatory modality, particularly in atypical presentations and in populations where radiation exposure must be avoided. Taken together, MAS and USG complement each other, and their combined use enhances diagnostic precision, reduces negative appendectomies, and optimizes patient outcomes.

The present study demonstrates that the Modified Alvarado Score (MAS) is more accurate than ultrasonographic evaluation in predicting histopathology-confirmed acute appendicitis among patients presenting with suspected appendicitis. MAS exhibited significantly higher sensitivity and overall diagnostic accuracy compared to ultrasonography, underscoring its value as a rapid, cost-effective, and clinically reliable screening tool particularly in settings where advanced imaging is limited. Although ultrasonography showed good positive predictive value and slightly higher specificity, its sensitivity and negative predictive value were inferior, reflecting its operator-dependent nature and reduced ability to exclude disease in equivocal cases. The combined use of MAS and ultrasonography improved diagnostic confidence, indicating that integrating clinical scoring with focused imaging offers the most balanced and pragmatic approach to reducing negative appendectomy rates and improving patient outcomes. Overall, MAS remains a strong initial diagnostic tool, while ultrasonography serves as an important adjunct in ambiguous or high-risk scenarios. LIMITATIONS OF THE STUDY 1. Single-center study: The research was conducted at one tertiary-care hospital, which may limit generalizability to other populations with varying demographic and clinical characteristics. 2. Operator dependency of ultrasonography: Variation in skill levels among radiologists and sonographers could have influenced diagnostic accuracy, particularly in technically challenging cases such as obese patients and retrocecal appendices. 3. Exclusion of pregnant women and specific subgroups: Excluding pregnant patients and those with appendicular masses or perforation may limit the applicability of results to these clinically important subpopulations. 4. Lack of CT imaging comparison: Computed tomography, known for its superior diagnostic performance, was not included as a comparative modality due to institutional and ethical considerations. 5. Potential selection bias: Only patients who underwent appendectomy were included, potentially overestimating diagnostic accuracy by excluding those managed conservatively or discharged without surgery. 6. Subjective clinical scoring: MAS relies partly on patient symptoms such as anorexia and subjective clinical signs, which may vary between observers and potentially influence scoring accuracy

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