Role of Computed Tomography in Differentiating between Benign and Malignant Gallbladder Masses with Histopathological Correlation

A cross-sectional study was done to evaluate computed tomography (CT) scans as a diagnostic tool for distinguishing between benign and malignant gallbladder masses corroborated by histopathological findings. The study was conducted in the Department of Radiology & Imaging of Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh, between January and December of 2013. The study included a total of 45 patients who were ultrasonographically diagnosed with gallbladder masses. Later, those patients underwent CT scans using a 16-slice helical CT scan machine. All CT scan findings were interpreted by the specialist radiologists, focusing on lesion involvement, contrast enhancement characteristics, and invasion into adjacent structures. Postoperative tissues were examined histopathologically, and these findings were correlated with the CT scan results. The study revealed a higher prevalence of GBC in females (73.33%) and in the age group of 40-60 years. CT scans indicated malignancy in 84.44% of cases, which was confirmed as adenocarcinoma in 88.89% of cases through histopathology. The sensitivity, specificity, and accuracy of CT scans for detecting malignant gallbladder masses were 90.24%, 75.00%, and 88.89%, respectively. For benign masses, the corresponding values were 75.00%, 90.24%, and 88.89%. The positive predictive value was notably high at 97.37% for malignant masses but lower at 42.86% for benign masses. CT scans demonstrated high sensitivity and specificity in the diagnosis of malignant gallbladder masses, corroborated by histopathological findings. The study underscores the utility of CT scans as an effective, non-invasive diagnostic tool for early detection and management of gallbladder masses, although caution is advised in interpreting benign results due to a lower positive predictive value.


Introduction
Gallbladder carcinoma (GBC) is a rare yet highly aggressive malignancy, ranking as the fifth most common gastrointestinal cancer and the leading cancer of the biliary tree. 1 Despite its severity, early diagnosis remains elusive due to often vague and non-specific symptoms that typically manifest at advanced stages, usually when adjacent organs like the liver are invaded. 2,3This late presentation is a significant contributor to the dismal prognosis of GBC, with most large studies reporting a five-year survival rate of less than 5%. 2 Recent advancements in medical imaging have revolutionized the diagnostic landscape for GBC.Ultrasonography (USG) is commonly the first-line imaging modality, particularly useful for initial evaluations of symptoms such as jaundice or right-upper quadrant pain. 4However, USG CBMJ 2024 January: Vol. 13 No. 01 has limitations, including interference from bowel gas and limited depth resolution.

Address of Correspondence:
Email: muktadira51@gmail.comRegarding gender distribution, the study had a higher representation of females, with 33 patients (73.33%), compared to 12 male patients (26.67%) (Table-I).Based on their CT scan findings, 38 patients (84.44%) were detected with malignancy of the gall bladder, while the rest 7 patients (15.56%) were diagnosed with benign masses of the gall bladder (Fig. 1).

Discussion
The demographic profile of the study population revealed a mean age of 50 years, with a male-tofemale ratio of 2:5.This is notably different from what is generally reported in Western literature, where the mean age of presentation is usually a decade higher.This discrepancy could be attributed to regional variations in disease prevalence or perhaps to advancements in imaging modalities that enable earlier detection.

Kumar et al.
12 also reported a similar trend in a North Indian population, suggesting that this might be a broader regional phenomenon.4][15] These symptoms often indicate more advanced stages of the disease, which is consistent with the low five-year survival rates reported by another study. 2The CT findings in this study are particularly noteworthy.
A majority of the cases (62.2%) presented with a mass in the gallbladder fossa, 17.8% had polypoidal growth, and 20% had gallbladder wall thickening.These observations are in line with those reported by George et al. 4 The study also underscores the diagnostic challenges posed by gallbladder wall thickening, which can be indicative of a range of conditions from chronic cholecystitis to carcinoma, as also noted by Levy et al. 16 and Yoshimitsu et al. 17 The study found cholelithiasis in 80% of the patients, which is consistent with its established role as a significant risk factor for gallbladder carcinoma.This supports the findings of Zissin et al. 14 and adds weight to the hypothesis that irritation from gallstones may lead to chronic inflammation and eventually to carcinoma, as described by Lamps. 18One of the most compelling aspects of this study is its diagnostic accuracy metrics.
approval was obtained from the ethical committee of the institution, and informed written consent was collected from each patient.Initially, 53 patients with clinically suspected gallbladder masses were considered; however, 7 were unfit for surgery due to metastasis, and one refused surgery, leaving 45 patients for final evaluation.These patients were selected irrespective of age and sex and underwent CT scans using a 16slice helical CT scan machine (Emotion 16, Siemens) with specific parameters.The CT scans were interpreted by specialist radiologists, focusing on lesion involvement, contrast enhancement characteristics, and invasion into adjacent structures.Postoperative tissues were examined histopathologically, and these findings were correlated with CT scan results.Data were collected using a semi-structured questionnaire and analyzed using SPSS (Statistical Package for Social Sciences).Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT scans were calculated based on histopathological findings using standard formulae.All statistical analysis was carried out using SPSS software version 20.0.All tests were two tailed and p<0.05 was considered to be statistically significant.The study was approved by the Ethical Review Committee of Sir Salimullah Medical College, Dhaka, Bangladesh.Results 45 patients, the age distribution was skewed towards the older population, with the majority falling within the 40-60 age range.Specifically, 17 patients (37.78%) were between 40-50 years old, and 20 patients (44.44%) were in the 50-60 age group.Fewer patients were observed in the younger and older age groups; only 1 patient (2.22%) was between 20-30 years, 3 patients (6.67%) were between 30-40 years, and 4 patients (8.89%) were between 60-70 years.The mean age of the participants was 50.66 years with a standard deviation of 2.35 years.

Fig. 1 :
Fig. 1: Distribution of patients by diagnosis of gallbladder mass using CT scans (N=45)

Table - II
: Comparison between CT scan and histopathological diagnosis for prediction of malignant gallbladder mass (N=45) CBMJ 2024 January: Vol. 13 No. 01 Table-IV: Comparison between CT and histopathological diagnosis for prediction of benign gallbladder mass (N=45)