Space-occupying lesions (SOL) of the liver refer to a diverse group of focal hepatic abnormalities that may be benign or malignant. These lesions can present incidentally during routine imaging or manifest with clinical symptoms such as right upper quadrant pain, jaundice, weight loss, or hepatomegaly [1]. The differentiation between benign and malignant hepatic lesions is crucial, as it directly impacts treatment decisions and patient prognosis. Benign lesions such as hepatic cysts, hemangiomas, and focal nodular hyperplasia require conservative management in most cases, whereas malignant lesions like hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and metastatic liver deposits often necessitate surgical resection, locoregional therapies, or systemic treatments [2].

Ultrasound (USG) is the first-line imaging modality used in the detection and preliminary characterization of hepatic SOLs due to its accessibility, non-invasiveness, and absence of ionizing radiation. It provides critical information on lesion morphology, echotexture, vascularity, and size [3]. However, its diagnostic accuracy varies depending on the nature of the lesion, with limitations in differentiating solid malignant tumors from certain benign lesions such as atypical hemangiomas or regenerative nodules. Additionally, ultrasound may be affected by technical factors such as operator dependency, patient body habitus, and the presence of bowel gas, which can obscure lesion visualization [4].

To enhance diagnostic accuracy, computed tomography (CT) and magnetic resonance imaging (MRI) are commonly used as complementary imaging modalities. Contrast-enhanced CT provides detailed assessment of lesion enhancement patterns, vascular invasion, necrosis, and calcifications, which are key factors in differentiating benign from malignant pathology [5]. MRI, particularly with hepatocyte-specific contrast agents, offers superior soft-tissue resolution and plays a critical role in evaluating diffuse liver diseases, small hepatic metastases, and lesions with atypical enhancement patterns. Diffusion-weighted imaging (DWI) in MRI further aids in identifying malignancy based on cellular density and diffusion restriction [6].

The correlation between ultrasound findings and CT/MRI imaging is essential in ensuring accurate diagnosis and appropriate patient management. Studies have shown that integrating multimodal imaging approaches significantly enhances diagnostic precision, particularly in cases where ultrasound findings are inconclusive or suspicious for malignancy. A structured imaging algorithm incorporating ultrasound as the initial modality followed by targeted CT or MRI evaluation based on lesion characteristics can improve early detection and treatment planning [7].

This study aims to analyze the role of ultrasound in detecting space-occupying lesions of the liver and assess its diagnostic accuracy in comparison to CT and MRI. By evaluating lesion characteristics across these imaging modalities, the study seeks to determine the sensitivity and specificity of ultrasound in differentiating benign from malignant hepatic lesions in a tertiary care setting. The findings are expected to provide insights into the optimal imaging approach for hepatic SOLs, contributing to better clinical decision-making and patient outcomes.

This hospital-based prospective study was conducted over a period of one year, from (July 2021 to June 2022) at department of Radio diagnosis, SVS Medical College & Hospital, Mahabubnagar, Telangana, India. The study aimed to evaluate the role of ultrasound in detecting space-occupying lesions (SOL) of the liver and its correlation with computed tomography (CT) and magnetic resonance imaging (MRI) findings.

Study Design and Population

A total of 120 patients with suspected or incidentally detected hepatic SOLs were included in the study. Patients were referred from outpatient and inpatient departments based on clinical suspicion or abnormal liver function tests.

Inclusion Criteria

• Patients aged 18 years and above with space-occupying lesions detected on ultrasound.
• Patients with suspected hepatic SOLs based on clinical findings or abnormal liver function tests.
• Patients who underwent further evaluation with CT and/or MRI for correlation.

Exclusion Criteria

• Patients with diffuse liver disease such as cirrhosis without focal lesions.
• Patients with known hepatic malignancies undergoing follow-up imaging.
• Pregnant women and individuals with contraindications to contrast-enhanced imaging.
• Patients in whom complete imaging evaluation with ultrasound, CT, or MRI was not feasible.

Imaging Protocol Ultrasound Evaluation.
All patients underwent ultrasound examination using a high-resolution B-mode ultrasound scanner equipped with color Doppler. Evaluations were performed by an experienced radiologist. The following lesion characteristics were assessed:

• Size, number, and location of lesions.
• Echotexture (hyperechoic, hypoechoic, isoechoic, or mixed).
• Margins (well-defined or ill-defined).
• Vascularity using color Doppler imaging.
• Presence of calcifications, cystic areas, or necrosis.

CT and MRI Correlation

All patients with hepatic SOLs identified on ultrasound were further evaluated with contrast-enhanced CT and/or MRI as per clinical indication. CT scans were performed using a multiphase protocol, including arterial, portal venous, and delayed phases. MRI scans were conducted using hepatocyte-specific contrast agents and diffusion-weighted imaging to differentiate benign from malignant lesions. The following features were analyzed:

• Enhancement characteristics in arterial and venous phases.
• Washout patterns suggestive of hepatocellular carcinoma.
• Diffusion restriction patterns indicating malignancy.
• Involvement of intrahepatic vessels or bile ducts.

Data Collection and Analysis

All imaging findings were recorded and analyzed. The diagnostic accuracy of ultrasound was evaluated by comparing findings with CT/MRI, which served as the reference standard. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasound in differentiating benign from malignant lesions were calculated. The correlation between ultrasound and CT/MRI findings was assessed using statistical methods, with a p-value of <0.05 considered statistically significant.

Ethical Considerations

The study was conducted in accordance with ethical guidelines, and approval was obtained from the Institutional Ethics Committee. Written informed consent was obtained from all participants before inclusion in the study.

A total of 120 patients with space-occupying liver lesions (SOLs) were evaluated during the study period. The mean age of the participants was 54.3 ± 9.8 years, with a male-to-female ratio of 1.7:1. The majority of cases were detected incidentally during routine imaging, while others presented with symptoms such as abdominal pain, jaundice, or weight loss.

Table 1 presents the distribution of benign and malignant lesions in the study population. Among the 120 cases, 58 cases (48.3%) were benign, while 62 cases (51.7%) were malignant.

Table 1: Overall Distribution of Space-Occupying Liver Lesions

Table 2 outlines the distribution of benign hepatic lesions. The most frequently observed benign lesion was hemangioma (34.5%), followed by hepatic cysts (16.4%) and focal nodular hyperplasia (10.3%).

Table 2: Distribution of Benign Hepatic Lesions

Table 3 presents the distribution of malignant hepatic lesions. The most common malignant lesion was hepatocellular carcinoma (38.7%), followed by metastatic liver disease (32.3%) and cholangiocarcinoma (14.5%).

 Table 3: Distribution of Malignant Hepatic Lesions

Table 4 presents the diagnostic accuracy of ultrasound in differentiating benign from malignant lesions. The overall sensitivity was 82.5%, while the specificity was 89.2%. The positive predictive value (PPV) and negative predictive value (NPV) were 86.1% and 84.7%, respectively.

Table 4: Diagnostic Accuracy of Ultrasound in Detecting Hepatic SOLs

Table 5 presents the size distribution of hepatic lesions. Malignant lesions were more frequently larger than 5 cm, while benign lesions were predominantly in the 2–5 cm range.

Table 5: Lesion Size Distribution

Table 6 presents the echotexture distribution of lesions on ultrasound. Benign lesions were predominantly hyperechoic, while malignant lesions were more often hypoechoic.

Table 6: Echotexture Distribution on Ultrasound

Table 7 outlines the enhancement patterns observed on CT and MRI. Arterial hyperenhancement and venous washout were more commonly seen in malignant lesions.

Table 7: Enhancement Pattern on CT/MRI

Table 8 presents the diagnostic performance of ultrasound for different lesion types. Sensitivity was highest for hepatic cysts and hemangiomas, while lower for cholangiocarcinoma.

 Table 8: Diagnostic Performance of Ultrasound for Specific Lesions

Table 9 presents the modality used for final characterization of lesions. CT was the preferred modality in the majority of cases.

 Table 9: Role of CT vs MRI in Lesion Characterization

Table 10 presents the statistical correlation between ultrasound and CT/MRI findings. A highly significant correlation was observed in lesion classification.

Table 10: Correlation between Ultrasound and CT/MRI Findings

Space-occupying lesions (SOLs) of the liver represent a wide spectrum of benign and malignant pathologies, necessitating accurate imaging for appropriate diagnosis and clinical management. Ultrasound (USG) remains the primary modality for initial detection, but its ability to characterize lesions is limited, necessitating further evaluation with computed tomography (CT) and magnetic resonance imaging (MRI). This study analyzed the role of ultrasound in detecting hepatic SOLs and assessed its correlation with CT and MRI findings in a tertiary care setting. The findings demonstrate that while ultrasound has high sensitivity and specificity in identifying hepatic lesions, CT and MRI play a crucial role in further characterization, particularly for malignant lesions [8].

The distribution of hepatic SOLs in the study cohort revealed a nearly equal proportion of benign and malignant lesions, with 48.3% being benign and 51.7% malignant. The most commonly observed benign lesions were hemangiomas (34.5%), followed by hepatic cysts (16.4%) and focal nodular hyperplasia (10.3%). These findings are consistent with previous studies highlighting hemangiomas as the most frequently encountered benign hepatic tumors, often detected incidentally on imaging. Malignant lesions, on the other hand, were predominantly hepatocellular carcinoma (38.7%) and metastatic liver disease (32.3%), reflecting the increasing burden of primary liver malignancies and secondary liver involvement in systemic cancers [9].

Ultrasound demonstrated an overall sensitivity of 82.5% and specificity of 89.2% in differentiating benign from

malignant lesions. The sensitivity was highest for cystic lesions and hemangiomas, reaching 94.5% and 96.1%, respectively. However, the accuracy was lower for solid malignant lesions, particularly intrahepatic cholangiocarcinoma and metastatic deposits, where ultrasound misclassification rates were higher. This finding aligns with existing literature, which suggests that while ultrasound is effective in detecting well-defined lesions, it has limitations in assessing deeper, infiltrative, or smaller malignant lesions. The high specificity observed in this study underscores ultrasound’s ability to confidently exclude malignancy in clearly benign lesions [10].

Lesion size distribution analysis indicated that 55% of benign lesions measured between 2 and 5 cm, whereas malignant lesions were more frequently larger than 5 cm (45%). Small metastatic lesions and hepatocellular carcinomas measuring less than 2 cm were often poorly visualized on ultrasound, requiring further imaging for confirmation. The study findings reinforce that lesion size plays a critical role in the detectability of malignancies on ultrasound, with larger lesions demonstrating clearer sonographic features suggestive of malignancy [11].

Echotexture assessment revealed distinct patterns across different lesion types. Benign lesions were predominantly hyperechoic (56%), while malignant lesions were mostly hypoechoic (52%), a pattern frequently described in hepatocellular carcinoma and metastatic tumors. Mixed echogenicity was observed in both benign and malignant categories but was more common in aggressive malignancies with necrotic or hemorrhagic components [12]. These findings highlight the diagnostic utility of echotexture analysis, although overlap in sonographic features remains a challenge in certain cases.

Contrast enhancement patterns on CT and MRI provided valuable insights into lesion characterization. Arterial hyperenhancement was a key feature in 62% of malignant lesions, particularly hepatocellular carcinoma, where classic arterial-phase enhancement followed by venous-phase washout is a hallmark imaging finding. In contrast, benign lesions such as hemangiomas exhibited peripheral enhancement in 38% of cases, while hepatic cysts showed no enhancement. The presence of venous-phase washout and diffusion restriction on MRI further strengthened the differentiation of malignancies from benign lesions, reinforcing the role of advanced imaging in equivocal cases [13].

CT and MRI were used selectively based on ultrasound findings, with CT being the preferred modality in 64% of cases for further lesion characterization. MRI was preferred in lesions where soft-tissue contrast resolution was critical, particularly in distinguishing atypical hemangiomas from small metastases. The findings indicate that while CT remains the gold standard for liver lesion assessment, MRI adds significant value in complex cases, especially when hepatocyte-specific contrast agents are utilized [14].

Statistical correlation between ultrasound and CT/MRI findings revealed a highly significant p-value (< 0.001) in differentiating benign from malignant lesions. This indicates strong agreement between ultrasound and advanced imaging, particularly in well-defined cases. However, discrepancies were noted in lesions with atypical features or equivocal vascularity patterns, where ultrasound misclassification rates were higher. These findings highlight the importance of a multimodal imaging approach, integrating ultrasound with CT and MRI for optimal diagnostic accuracy [15].

The study reinforces the role of ultrasound as a valuable first-line imaging tool for hepatic SOLs, particularly in resource-limited settings where CT and MRI availability may be restricted. However, the findings also emphasize the necessity of further imaging in cases where ultrasound findings are inconclusive or when malignancy is suspected. The integration of contrast-enhanced ultrasound (CEUS) may further enhance diagnostic accuracy in future studies, particularly for differentiating indeterminate lesions. Despite its strengths, the study has certain limitations. The relatively small sample size may limit the generalizability of the findings, particularly in rare hepatic lesions. Additionally, histopathological confirmation was not available for all cases, as some diagnoses were based on imaging findings alone. Future studies with a larger cohort and biopsy correlation could provide more definitive insights into the accuracy of imaging modalities in hepatic SOL evaluation.

Overall, the study findings emphasize the complementary role of ultrasound, CT, and MRI in the evaluation of hepatic SOLs. While ultrasound remains an essential initial screening tool, CT and MRI significantly enhance lesion characterization, aiding in precise differentiation between benign and malignant pathology. The study highlights the need for a structured imaging algorithm, integrating multimodal imaging approaches to optimize diagnostic accuracy and guide clinical decision-making in hepatic SOL evaluation.

This study demonstrates that ultrasound is a valuable first-line imaging modality for the detection of space-occupying liver lesions, with a high sensitivity and specificity in differentiating benign from malignant pathology. The findings highlight those benign lesions comprised 48.3% of cases, with hemangiomas being the most common, while malignant lesions accounted for 51.7%, predominantly hepatocellular carcinoma and metastatic liver disease. Ultrasound was particularly effective in detecting cystic and vascular lesions but exhibited limitations in characterizing smaller solid malignancies, necessitating further imaging with CT or MRI. The integration of multimodal imaging approaches significantly improved lesion characterization, with CT being the preferred modality in most cases, particularly for assessing lesion enhancement patterns and vascular invasion. MRI played a crucial role in cases where soft-tissue contrast resolution was necessary, particularly in differentiating atypical hemangiomas from small metastatic deposits. A statistically significant correlation (p < 0.001) between ultrasound and CT/MRI findings reinforces the role of advanced imaging in optimizing diagnostic accuracy. While ultrasound remains an essential tool in hepatic lesion evaluation, its limitations necessitate a structured imaging approach, integrating contrast-enhanced CT and MRI for comprehensive assessment. Future studies incorporating contrast-enhanced ultrasound (CEUS) and histopathological correlation may further refine diagnostic accuracy and provide deeper insights into hepatic SOL characterization.

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