Although conventional TUS serves as an initial investigation for patients with cholelithiasis and choledocholithiasis, it can also identify dilatation of the biliary tree in 85-95% of cases with confirmed obstruction [7]. EUS has demonstrated high sensitivity, up to 97%, in detecting CBD stones. This technique is regarded as safe and beneficial in identifying patients who would benefit from therapeutic ERCP, potentially avoiding unnecessary risks associated with ERCP when its need is uncertain [7].

Several studies have reported a mean age of 55-59 years with a genetic predisposition toward the male gender for this disease. However, in this study, the overall mean age of patients was 38.41 ± 14.8, and the females (57.3%) were found to be more affected, with a mean age of 34.19 ± 13.9 years. This finding aligns with the study conducted by Bansal and colleagues, where they concluded that the mean age of patients was 47.9 ± 18.87 years, with 54.7% female sufferers in the majority, compared to 45.3% male, contradicting the outcomes of multiple studies [9]. In contrast, Anwer et al. [10], Wang et al. [11], Netinatsunton et al. [12], and Khan et al. [13] found that 51.2%, 58.4%, 41.1%, and 58.5% of males were more affected and showed a high tendency to develop CBD stones than females, with mean ages of 50, 59, 55, and 50 years, respectively.

In this comparative study, EUS outperformed TUS in detecting CBD stones, demonstrating a specificity approaching 100%. TUS demonstrated a sensitivity of 65.4% and a specificity of 58% for detecting gallstones, and a sensitivity of 39.3% and a specificity of 66% for detecting CBD stones. These results indicate a high number of false negatives for TUS in this study. Similar findings were reported by Khan and colleagues, who also found a low sensitivity of 29.2% [13]. Additionally, Makmun et al. observed a low sensitivity range of 15-40% for detecting bile duct stones (choledocholithiasis) [14]. The literature attributes the low sensitivity of TUS to its subjective nature, effort in distinguishing air bubbles from other auditory shadows (as seen in cholangitis), intervention from abdominal fat and bowel gas shadows, and the tool's limitation in detecting smaller stones [15].

Furthermore, in our study, EUS exhibited a high diagnostic sensitivity of 92.9%, specificity of 100%, PPV of 100%, and NPV of 99.9% for bile duct stones, which showed the superiority of EUS over TUS. Netinatsunton and colleagues [12] conducted a cohort study that detected CBD stones in 59 patients using EUS, which were later confirmed by ERCP. In the high-risk category, EUS showed 96% sensitivity, 100% specificity, 100% PPV, and 77% NPV, respectively, in identifying typical bile duct stones [12]. In the intermediate-risk, EUS detected choledocholithiasis in 26 out of 73 subjects [12]. However, subsequent ERCP confirmed the presence of stones in only 24 of these 26 EUS-positive cases, resulting in two false positives. EUS exhibited a commendable overall sensitivity of 96% and specificity of 95.80% in discerning choledocholithiasis within this risk stratum. Its PPV was 92.30%, while its NPV stood at 97.90%. Post-procedural complications were notably absent in individuals undergoing EUS. Conversely, 6.3% of those undergoing ERCP encountered adverse events, such as mild pancreatitis, hemorrhage secondary to sphincterotomy, and sphincterotomy-associated perforations, necessitating prolonged hospitalization durations [13].

In a study by Chang and his coworkers [16], two patients were found to have CBD stones, while one had CBD sludge, all of which were only detected using EUS. Patients with microlithiasis in the CBD faced an elevated risk of developing complications such as biliary obstruction, cholangitis, and acute pancreatitis. Additionally, the high NPV of EUS was crucial in excluding choledocholithiasis [16]. Another study examined the characteristics of patients and the recurrence of EUS findings. The study concluded that higher levels of alanine transaminase or alkaline phosphatase upon admission, a prior history of cholecystectomy, and non-lithiasis findings on EUS were linked to a higher likelihood of experiencing a new episode of acute pancreatitis [17].

Limitations

The study has several limitations that need to be considered. Firstly, the selection of all study participants and EUS examinations were done by one experienced doctor, which introduces the possibility of selection bias in our study. This reliance on a single individual might affect the generalizability of the study findings. Secondly, it was a single-center study, and results may not be representative of a larger population. Lastly, post-procedure complications were not considered for this study.