Focal liver lesions are commonly encountered in clinical radiology and include a wide spectrum of benign, inflammatory, infective, premalignant and malignant conditions. Their detection may occur during evaluation of abdominal symptoms, chronic liver disease, known extrahepatic malignancy, abnormal liver function tests, or as incidental findings on ultrasound, CT or MRI. Accurate characterisation is clinically important because management varies widely from reassurance or follow-up in benign lesions to biopsy, surgery, ablation, chemotherapy, transplantation or oncological staging in malignant lesions [1]. The American College of Radiology recommends MRI abdomen without and with intravenous contrast as a usually appropriate modality for characterising many indeterminate liver lesions detected on initial imaging.

Ultrasonography is often used as the first-line screening modality because it is inexpensive, widely available and free of ionising radiation. However, its diagnostic performance may be limited by patient habitus, operator dependence, bowel gas, lesion depth and overlapping appearances between benign and malignant lesions. Multiphase CT provides useful vascular phase information but involves ionising radiation and iodinated contrast exposure. MRI offers superior soft tissue contrast, multiplanar capability and multiparametric assessment using T1-weighted imaging, T2-weighted imaging, fat-suppressed sequences, in-phase/opposed-phase imaging, heavily T2-weighted imaging, diffusion-weighted imaging and dynamic contrast-enhanced sequences [1,2].

MRI characterisation of focal liver lesions is based on a combined assessment of morphology, background liver status, signal intensity, diffusion restriction and enhancement pattern. Cystic lesions are evaluated by wall thickness, septations, mural nodules, calcification, internal contents, communication with bile ducts and post-contrast enhancement [7]. Hemangiomas typically show marked T2 hyperintensity and peripheral nodular discontinuous enhancement with progressive centripetal fill-in, while simple cysts show fluid signal intensity and absence of enhancement [7,10,11]. Malignant lesions such as metastases and hepatocellular carcinoma may show variable T1 and T2 signal, diffusion restriction, arterial phase enhancement, washout, rim enhancement, peripheral washout, heterogeneous enhancement or vascular invasion depending on tumour type and vascularity [4,8].

In patients with cirrhosis or other high-risk backgrounds, MRI has a central role in the non-invasive diagnosis of hepatocellular carcinoma. Current imaging systems such as LI-RADS and recent hepatology/radiology recommendations emphasise major imaging features including lesion size, non-rim arterial phase hyperenhancement, non-peripheral washout, enhancing capsule and threshold growth [3,4]. The 2025 EASL guideline provides updated evidence-based recommendations for management of hepatocellular carcinoma, while the 2024 ESGAR/ESR practice recommendations summarise essential imaging criteria for HCC diagnosis [2,3].

Dynamic contrast-enhanced MRI is especially useful because many focal liver lesions demonstrate characteristic vascular behaviour across arterial, portal venous, equilibrium and delayed phases. Hepatocellular carcinoma commonly demonstrates arterial phase hyperenhancement with washout in the portal venous or delayed phase, whereas cholangiocarcinoma more often shows progressive delayed enhancement due to fibrous stroma. Metastases may show peripheral rim enhancement, heterogeneous enhancement or delayed peripheral washout depending on the primary tumour and lesion vascularity [6,8]. Addition of diffusion-weighted imaging and hepatobiliary contrast agents may further improve lesion detection and confidence, particularly for small lesions and lesions in cirrhotic liver [1,4].

Although imaging patterns are often characteristic, overlap may occur between metastasis and atypical hepatocellular carcinoma, between abscess and necrotic tumour, and between complex cystic neoplasms and complicated benign cysts. Therefore, correlation with clinical history, laboratory findings, background liver disease, tumour markers, histopathology, FNAC, biopsy or follow-up imaging remains important where imaging findings are indeterminate [1,7]. In this context, the present study was designed to evaluate MRI characteristics of focal liver lesions and correlate radiological diagnosis with histopathological or follow-up findings.

Aim

To evaluate the role of magnetic resonance imaging in the characterization of focal liver lesions and to correlate MRI diagnosis with histopathological or follow-up findings.

Objectives

1. To assess the MRI characteristics of focal liver lesions based on lesion number, location, size, margins, signal intensity, internal architecture, diffusion characteristics, and dynamic contrast enhancement pattern.
2. To correlate the MRI diagnosis of focal liver lesions with final histopathological diagnosis, FNAC, biopsy, or follow-up imaging wherever applicable.

Study Design This was a prospective observational study conducted in the Department of Radiodiagnosis, Maheswara Medical College & General Hospital, over a period of one year from January 2024 to December 2024. Study Population The study included 40 patients who were referred to the Department of Radiodiagnosis for MRI evaluation of focal liver lesions. All patients underwent MRI liver protocol for characterization of the lesion. The MRI findings were correlated with FNAC, biopsy, operative histopathology, or follow-up imaging wherever applicable. Sample Size A total of 40 patients with focal liver lesions were included in the study. Study Setting Department of Radiodiagnosis, Maheswara Medical College &General Hospital. Study Duration One year, from January 2024 to December 2024. Inclusion Criteria All patients referred for MRI evaluation of focal liver lesions were included in the study. Exclusion Criteria Patients were excluded from the study if they had: 1. Contraindications to MRI, such as incompatible metallic implants, cardiac pacemakers, or severe claustrophobia. 2. Contraindications to gadolinium-based contrast administration. 3. Poor image quality due to motion artefacts or inability to cooperate during MRI acquisition. 4. Incomplete clinical, imaging, or follow-up data. MRI Technique MRI of the liver was performed using a 1.5 Tesla MRI scanner with a phased-array body coil. Patients were positioned supine, and routine liver MRI protocol was performed. Pre-contrast and post-contrast sequences were obtained for lesion detection, characterization, and assessment of lesion extent. MRI Sequences Used The following sequences were included in the MRI protocol: 1. Axial T1-weighted imaging. 2. Axial and coronal T2-weighted imaging. 3. Fat-suppressed T2-weighted imaging. 4. Dual-echo in-phase and out-of-phase imaging. 5. Heavily T2-weighted imaging. 6. Diffusion-weighted imaging. 7. Dynamic contrast-enhanced imaging after intravenous gadolinium administration. 8. Delayed post-contrast imaging. Dynamic contrast-enhanced imaging was obtained in arterial, portal venous, equilibrium, and delayed phases after administration of gadolinium contrast. Parameters Assessed on MRI Each lesion was evaluated according to the following MRI features: 1. Number of lesions: single, double, or multiple. 2. Location of lesion: right lobe, left lobe, or both lobes. 3. Size of the largest lesion. 4. Margin of lesion: well-defined, lobulated, irregular, or ill-defined. 5. Internal structure: cystic/water content, hemorrhagic content, fat content, or nonspecific solid/heterogeneous structure. 6. Signal intensity on T1-weighted images: hypointense, isointense, hyperintense, or heterogeneous. 7. Signal intensity on T2-weighted images: hypointense, isointense, hyperintense, or heterogeneous. 8. Appearance on heavily T2-weighted images: increase in signal intensity, decrease in signal intensity, or no significant change. 9. Diffusion restriction: present or absent. 10. Enhancement pattern on contrast-enhanced MRI. Contrast Enhancement Patterns Studied The enhancement patterns assessed included: 1. No enhancement. 2. Arterial phase enhancement. 3. Ring enhancement. 4. Rim enhancement. 5. Peripheral washout. 6. Delayed enhancement. 7. Nodule-within-nodule enhancement. 8. Peripheral globular enhancement with progressive centripetal fill-in. 9. Thick wall enhancement. 10. Heterogeneous enhancement. Diagnostic Criteria MRI diagnosis was made based on morphology, signal characteristics, diffusion restriction, and enhancement pattern. Metastases were diagnosed when lesions were multiple or bilobar and showed irregular margins, T1 hypointensity or isointensity, T2 hyperintensity, peripheral washout, ring enhancement, or heterogeneous enhancement. Hepatocellular carcinoma was diagnosed when lesions showed arterial phase enhancement, heterogeneous enhancement, nodule-within-nodule appearance, washout pattern, associated cirrhosis, or vascular invasion. Cholangiocarcinoma was diagnosed when lesions showed irregular morphology with progressive delayed enhancement. Hemangioma was diagnosed when lesions were well-defined or lobulated, T1 hypointense, markedly T2 hyperintense, and showed peripheral globular enhancement with progressive centripetal fill-in. Simple cysts were diagnosed when lesions were well-defined, T1 hypointense, T2 hyperintense, and showed no post-contrast enhancement. Abscess was diagnosed when lesions showed rim enhancement, diffusion restriction, and clinical correlation with infective features. Regenerating and dysplastic nodules were diagnosed in cirrhotic liver based on signal characteristics and absence or pattern of enhancement. Histopathological and Follow-Up Correlation MRI diagnosis was correlated with FNAC, biopsy, operative histopathology, or follow-up imaging wherever applicable. Malignant lesions such as metastasis, hepatocellular carcinoma, and cholangiocarcinoma were confirmed by FNAC, biopsy, or histopathological examination. Benign lesions such as simple cysts and hemangiomas were followed up by ultrasonography or clinical-imaging correlation where biopsy was not indicated. Statistical Analysis Data were entered into a spreadsheet and analyzed using descriptive statistics. Categorical variables such as sex, lesion type, lesion number, location, margin, signal intensity, and enhancement pattern were expressed as frequencies and percentages. Continuous variables such as age and lesion size were expressed as mean and standard deviation where applicable. Diagnostic performance of MRI was calculated using sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for major malignant lesions such as metastasis, hepatocellular carcinoma, and cholangiocarcinoma. Ethical Considerations Institutional ethics committee approval was obtained before the start of the study. Written informed consent was obtained from all patients before MRI examination and contrast administration. Patient confidentiality was maintained throughout the study.

A total of 40 patients with focal liver lesions were evaluated by magnetic resonance imaging over a period of one year from January 2024 to December 2024 in the Department of Radiodiagnosis, Maheswara Medical College &General Hospital. MRI findings were assessed with respect to lesion number, location, size, margins, internal architecture, T1-weighted signal intensity, T2-weighted signal intensity, heavily T2-weighted signal characteristics, diffusion restriction, and dynamic contrast enhancement pattern. The MRI diagnosis was correlated with FNAC, biopsy, or imaging follow-up wherever applicable.

The age of the patients ranged from 27 to 80 years, with a mean age of 53.1 ± 12.8 years. Out of 40 patients, 27 were males and 13 were females, giving a male-to-female ratio of approximately 2.1:1.

Table 1. Age Distribution of the Study Population

Most patients were in the 51–60 year age group, followed by the 41–50 year age group. Focal liver lesions were more commonly observed in middle-aged and elderly patients.

Table 2. Sex Distribution

Males were more commonly affected than females, with a male-to-female ratio of approximately 2.1:1.

Table 3. Distribution of Focal Liver Lesions Based on MRI Diagnosis

Metastasis was the most common focal liver lesion, followed by hepatocellular carcinoma. Malignant lesions constituted the majority of cases, while hemangioma was the most common benign solid lesion.

Table 4. Distribution of Malignant and Benign Lesions

Malignant lesions were more frequent than benign lesions in the present study. Metastasis, hepatocellular carcinoma, and cholangiocarcinoma together formed the malignant group.

Table 5. Status of Background Liver

Most lesions were seen in a non-cirrhotic liver background. Cirrhosis was mainly associated with hepatocellular carcinoma and regenerating/dysplastic nodules.

Table 6. Number and Location of Lesions

Multiple lesions were more common than solitary lesions. Bilobar involvement was the most frequent pattern, particularly in metastatic disease.

Table 7. Size of Largest Lesion

Most lesions measured more than 2 cm. Larger lesions were commonly seen in malignant lesions such as metastasis, hepatocellular carcinoma, and cholangiocarcinoma.

Table 8. Margin of Lesions

Lobulated and irregular margins were commonly observed. Lobulated margins were frequently seen in hemangiomas, while irregular or ill-defined margins were more commonly associated with malignant lesions.

Table 9. Internal Structure of Lesions

Most lesions showed nonspecific solid or heterogeneous internal architecture. Cystic internal structure was seen in simple cysts, hydatid cyst, biliary cystadenoma, and PCKD-associated hepatic cysts.

Table 10. Signal Characteristics on MRI

Most focal liver lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. Heavily T2-weighted imaging was useful in identifying lesions with high fluid content and hemangiomas.

Table 11. Enhancement Pattern on Contrast-Enhanced MRI

Dynamic contrast-enhanced MRI helped in lesion characterisation. Peripheral washout was commonly associated with metastasis. Heterogeneous arterial enhancement and nodule-within-nodule enhancement supported hepatocellular carcinoma. Delayed enhancement was seen in cholangiocarcinoma, while peripheral globular enhancement with centripetal fill-in was characteristic of hemangioma.

Table 12. MRI Features According to Lesion Type

Morphology, background liver status, and enhancement pattern together helped in narrowing the MRI diagnosis of focal liver lesions.

Table 13. MRI–Histopathology Correlation for Major Malignant Lesions

MRI showed good correlation with FNAC/biopsy in malignant focal liver lesions. The main diagnostic overlap was between metastasis and hepatocellular carcinoma.

Table 14. Diagnostic Performance of MRI for Major Malignant Lesions

MRI showed high sensitivity, specificity, and diagnostic accuracy for differentiating major malignant focal liver lesions. The diagnostic accuracy was highest for cholangiocarcinoma, while metastasis and hepatocellular carcinoma showed minor overlap due to similar enhancement patterns in a few cases

Figure 1. Distribution of focal liver lesions on MRI among 40 patients. Metastasis was the most common lesion, followed by hepatocellular carcinoma, hemangioma, and cholangiocarcinoma.

Figure 2. Distribution of malignant and benign lesions. Malignant lesions accounted for 23 cases (57.5%), while benign lesions accounted for 17 cases (42.5%).

Figure 3. Sex distribution of the study population. Males constituted 27 cases (67.5%) and females constituted 13 cases (32.5%).

Figure 4. Number and location of focal liver lesions. Multiple lesions were the most common pattern, and bilobar involvement was the most common location pattern.

Figure 5. Diagnostic performance of MRI for major malignant focal liver lesions. MRI showed high sensitivity, specificity, and accuracy for metastasis, hepatocellular carcinoma, and cholangiocarcinoma.

Figure 1. Histopathology of hepatic metastasis. H&E-stained section demonstrating metastatic adenocarcinoma composed of irregular malignant glandular structures infiltrating the hepatic parenchyma, with nuclear pleomorphism and areas of tumour necrosis.

Figure 2. Histopathology of cavernous hepatic hemangioma. H&E-stained section showing multiple dilated blood-filled vascular spaces separated by thin fibrous septa and lined by flattened bland endothelial cells without significant cytological atypia.

Figure 3. Histopathology of focal nodular hyperplasia. H&E-stained section showing nodules of benign-appearing hepatocytes separated by fibrous septa containing thick-walled vessels, inflammatory cells and proliferating bile ductules.

In this study, 5 In the present study, 40 patients with focal liver lesions were evaluated using magnetic resonance imaging, with final diagnosis established by FNAC, biopsy, operative histopathology, or imaging follow-up wherever appropriate. MRI permitted assessment of lesion number, location, size, margins, background liver morphology, T1- and T2-weighted signal characteristics, heavily T2-weighted appearance, diffusion behaviour, and dynamic contrast enhancement. Taken together, these parameters allowed satisfactory differentiation of most benign and malignant focal liver lesions. Malignant lesions constituted 23 cases (57.5%), while 17 cases (42.5%) were benign. Metastases were the most common lesions, accounting for 11 cases (27.5%), followed by hepatocellular carcinoma (HCC) in 8 cases (20%), hemangioma in 5 cases (12.5%), and cholangiocarcinoma in 4 cases (10%). This pattern was comparable to the study by Ajitha et al., who evaluated 30 patients with focal liver lesions using MRI and pathological correlation and similarly found metastases to be the most frequent lesion, followed by HCC, hemangioma, and cholangiocarcinoma [12]. The similarity in lesion distribution supports the relevance of metastatic disease and primary hepatocellular malignancy as major indications for MRI characterisation of focal hepatic lesions. The patients in the present study ranged from 27 to 80 years of age, with a mean age of 53.1 ± 12.8 years. Males constituted 67.5% of cases, giving a male-to-female ratio of approximately 2.1:1. Ajitha et al. also reported a comparable age range and male predominance [12]. However, the demographic pattern should be interpreted in relation to the underlying disease spectrum rather than considered an independent characteristic of focal liver lesions, because the age and sex distribution varies considerably between metastatic disease, HCC, benign lesions, and infective lesions. Most patients in the present study had multiple lesions (57.5%), while 30% had solitary lesions and 12.5% had two lesions. Bilobar involvement was present in half of the patients. A similar predominance of multiple and bilobar lesions was observed by Ajitha et al. [12]. In the present series, this pattern was largely related to the relatively high frequency of metastatic disease. Multiplicity and bilobar distribution are useful diagnostic clues, although they are not specific for metastases and must be interpreted with lesion morphology, enhancement characteristics, diffusion findings, clinical history, and the presence or absence of chronic liver disease. Metastases constituted the largest individual diagnostic group, accounting for 11 cases. MRI correctly identified 10 cases, with one false-positive and one false-negative diagnosis. The calculated sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 90.9%, 96.6%, 90.9%, 96.6%, and 95%, respectively. The performance observed in this relatively small series is consistent with the established diagnostic value of MRI for liver metastases. Vilgrain et al., in a meta-analysis involving 39 studies, 1,989 patients and 3,854 metastases, reported per-lesion sensitivities of 87.1% for diffusion-weighted MRI, 90.6% for gadoxetic acid-enhanced MRI, and 95.5% when both techniques were combined [13]. This is particularly relevant because the combined use of morphological, contrast-enhanced, and diffusion-weighted sequences provides complementary information rather than relying on any single imaging feature. Lee et al. demonstrated that gadoxetic acid-enhanced MRI had significantly better diagnostic performance than triple-phase multidetector CT for the detection of hepatic metastases, with the advantage being particularly marked for lesions measuring 1 cm or less [14]. Similarly, Vreugdenburg et al., in a systematic review and meta-analysis, found hepatocyte-specific gadoxetic acid-enhanced MRI to be significantly more sensitive than contrast-enhanced CT for detecting liver metastases, with the greatest difference occurring for lesions smaller than 10 mm [15]. Choi et al. also demonstrated a high diagnostic performance of gadoxetate-enhanced MRI in their systematic review and meta-analysis comparing CT, MRI, and PET/CT for colorectal liver metastases [16]. These studies support the overall diagnostic strength of MRI for metastatic disease, although their findings should not be considered numerically interchangeable with the present study because different MRI protocols, contrast agents, patient populations, and reference standards were used. Hepatocellular carcinoma was the second most common malignant lesion in the present study, accounting for 8 cases (20%). MRI correctly diagnosed 7 cases, resulting in a sensitivity of 87.5%, specificity of 96.9%, PPV of 87.5%, NPV of 96.9%, and overall diagnostic accuracy of 95%. Important findings included arterial or heterogeneous enhancement, subsequent washout in appropriate lesions, nodule-within-nodule appearance, background cirrhotic changes, and evidence of vascular involvement. The diagnostic interpretation of HCC should, however, always take the background liver and clinical risk status into account. The 2021 AASLD Practice Guidance emphasises the importance of multiphasic contrast-enhanced CT or MRI for non-invasive HCC diagnosis in appropriate at-risk populations and supports the use of standardised imaging criteria such as LI-RADS [17]. Thus, arterial phase hyperenhancement or washout should not be interpreted in isolation. Lesion size, enhancement pattern, capsule appearance, interval growth, associated vascular findings, and the presence of cirrhosis or other HCC risk factors together determine diagnostic confidence. This is particularly important in the present study because one lesion interpreted as metastatic disease proved to be HCC and one lesion considered HCC was subsequently diagnosed as metastasis. Cholangiocarcinoma accounted for 4 cases (10%), all of which were correctly identified on MRI and subsequently confirmed histopathologically. The lesions showed imaging characteristics compatible with cholangiocarcinoma, including delayed enhancement. Progressive or delayed enhancement reflects, in part, the abundant fibrous stromal component of many cholangiocarcinomas. Although sensitivity, specificity, PPV, NPV, and accuracy were calculated as 100% in this subgroup, these figures should be interpreted cautiously. With only four cases, a single additional misclassified lesion would substantially alter the calculated diagnostic indices; therefore, the result indicates successful classification within this series rather than definitive evidence of perfect diagnostic performance. Hemangioma was the commonest benign solid lesion, accounting for 5 cases (12.5%). Typical findings included well-defined or lobulated margins, low signal intensity on T1-weighted sequences, marked hyperintensity on T2- and heavily T2-weighted sequences, and peripheral discontinuous or globular enhancement with progressive centripetal fill-in. These characteristics correspond to the recognised MRI appearance of cavernous hemangioma. Earlier studies by Li et al. and Lombardo et al. demonstrated the value of T2-weighted signal characteristics and enhancement behaviour in differentiating hepatic hemangiomas from metastases [10,11]. More recent reviews continue to emphasise the ability of multiparametric MRI to characterise typical benign focal liver lesions and thereby avoid unnecessary invasive procedures [18]. The remaining benign, infective, and cystic lesions included simple hepatic cysts, biliary cystadenoma, hydatid cyst, pyogenic abscess, regenerating or dysplastic nodules, and hepatic cysts associated with polycystic kidney disease. Simple cysts typically demonstrated low T1 signal, very high T2 signal, and absence of internal enhancement. Complex cystic lesions were characterised by additional features such as wall thickening, septations, internal contents, or enhancing components. Mortelé and Ros described these morphological features as important discriminators among cystic focal liver lesions [7]. The presence of restricted diffusion and rim enhancement in an abscess may provide additional diagnostic information, but such findings require clinical correlation because diffusion restriction is not specific for malignancy. Diffusion-weighted imaging contributed useful additional information in the present study, particularly when interpreted together with conventional sequences and contrast-enhancement patterns. Malignant lesions frequently demonstrate lower apparent diffusion coefficient values because of increased cellularity and restriction of water movement. Nevertheless, considerable overlap exists between benign and malignant lesions, and abscesses may also show marked restriction. Therefore, DWI should be regarded as a complementary rather than independent diagnostic technique. Jain et al. demonstrated a significant difference in ADC values between benign and malignant solid hepatic lesions. Using an absolute ADC cut-off of approximately 1.26 × 10⁻³ mm²/s, they reported sensitivity of 92%, specificity of 80%, and overall accuracy of 89%; an ADC lesion-to-liver ratio also provided useful discrimination [19]. Noda et al. subsequently evaluated mono-exponential, bi-exponential, and stretched-exponential diffusion models and demonstrated that quantitative diffusion parameters could contribute to differentiation between benign and malignant hepatic lesions [20]. These findings support the use of DWI and ADC analysis in liver MRI while also highlighting the need to interpret quantitative values within the context of the acquisition technique and the remaining MRI findings. Dynamic contrast enhancement remained a central component of lesion characterisation in the present study. Different enhancement patterns contributed to differentiation among metastatic disease, HCC, cholangiocarcinoma, hemangioma, and complex cystic or inflammatory lesions. The earlier work of Hamm et al. demonstrated that dynamic gadolinium-enhanced MRI adds diagnostic information to non-enhanced MRI in the characterisation of focal hepatic lesions and that incorporation of clinical information further improves interpretation [6]. This remains relevant to the present study, in which imaging findings were considered together with background liver status, clinical history, suspected primary malignancy, pathological findings, and follow-up. Evidence also supports the complementary value of combining contrast-enhanced MRI with diffusion imaging. Koh et al. found that combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI significantly improved the detection of colorectal liver metastases compared with either dataset alone [21]. The multicentre randomized trial by Zech et al. further demonstrated greater diagnostic confidence with gadoxetic acid-enhanced MRI than with conventional extracellular contrast-enhanced MRI or contrast-enhanced CT in patients evaluated for colorectal liver metastases [22]. These studies illustrate the direction in which contemporary liver MRI has evolved: from morphological evaluation alone toward integrated multiparametric assessment incorporating diffusion, vascular-phase behaviour, and, where available, hepatobiliary-phase imaging. It is important, however, to distinguish these hepatobiliary contrast-agent studies from the present investigation if a hepatocyte-specific contrast agent was not part of the study protocol. Their results strengthen the broader evidence supporting MRI for focal liver lesion assessment but should not be used to claim identical performance for every MRI protocol. Diagnostic accuracy depends on field strength, sequence parameters, contrast agent, timing, lesion size, underlying liver disease, reader expertise, and the method used to establish the final diagnosis. The principal diagnostic overlap in the present study occurred between metastatic disease and HCC. This finding is clinically understandable because atypical HCC may show necrosis, heterogeneous enhancement, peripheral components, or reduced arterial hypervascularity, whereas some hypervascular metastases may resemble HCC. The 2021 AASLD guidance reinforces the importance of interpreting characteristic enhancement features in the appropriate at-risk population rather than diagnosing HCC from a single imaging sign [17]. Clinical history and identification of a known extrahepatic primary tumour are similarly essential when considering metastatic disease. Overall, the findings of the present study demonstrate that MRI provides high diagnostic performance in the characterisation of focal liver lesions. The sensitivity and specificity were 90.9% and 96.6% for metastases and 87.5% and 96.9% for HCC, while all four cholangiocarcinomas were correctly classified. MRI offers the advantage of combining anatomical detail, tissue contrast, T1- and T2-weighted characteristics, diffusion behaviour, vascular enhancement patterns, assessment of the background liver, and evaluation of vascular and biliary relationships within a single examination. These characteristics make MRI particularly valuable when ultrasound or CT findings remain indeterminate and when accurate lesion characterisation may alter further investigation or treatment planning. Several limitations should be considered while interpreting these findings. The sample size was relatively small and the study was conducted at a single centre. Some diagnostic subgroups contained only a few patients, making estimates such as the 100% diagnostic performance for cholangiocarcinoma statistically unstable. Histopathological confirmation was not available for every benign lesion, with imaging follow-up serving as the reference standard in selected cases; this introduces a potential for verification bias. The heterogeneous spectrum of lesions also limits precise lesion-specific comparison. In addition, quantitative ADC thresholds may vary among scanners and imaging protocols and therefore should not be generalised without standardisation. Future studies should include larger multicentre populations, more balanced representation of individual lesion types, standardised diffusion protocols and ADC measurements, and uniform reference standards whenever feasible. Incorporation of hepatocyte-specific contrast agents and standardised reporting systems such as LI-RADS in appropriate at-risk patients may further improve diagnostic reproducibility. Despite its limitations, the present study supports MRI as a comprehensive and clinically useful modality for the detection and characterisation of focal liver lesions.

In the present study of 40 patients with focal liver lesions, MRI proved to be a highly useful imaging modality for lesion detection, characterisation, and correlation with histopathological or follow-up findings. MRI allowed assessment of lesion number, location, size, margins, internal architecture, T1- and T2-weighted signal characteristics, heavily T2-weighted signal behaviour, diffusion restriction, and dynamic contrast enhancement pattern.

Malignant lesions were more common than benign lesions, accounting for 23 cases (57.5%), while benign lesions accounted for 17 cases (42.5%). Metastasis was the most common focal liver lesion, followed by hepatocellular carcinoma, hemangioma, and cholangiocarcinoma. Dynamic contrast-enhanced MRI showed characteristic enhancement patterns that helped in differentiating metastasis, hepatocellular carcinoma, cholangiocarcinoma, hemangioma, cystic lesions, abscess, and regenerative or dysplastic nodules.

MRI demonstrated high diagnostic performance for major malignant lesions. The sensitivity, specificity, and diagnostic accuracy were 90.9%, 96.6%, and 95% for metastasis; 87.5%, 96.9%, and 95% for hepatocellular carcinoma; and 100%, 100%, and 100% for cholangiocarcinoma, respectively. The main diagnostic overlap was observed between metastasis and hepatocellular carcinoma, indicating that atypical enhancement patterns should be interpreted along with clinical background, cirrhosis status, tumour markers, FNAC, biopsy, or follow-up imaging.

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Thus, comprehensive MRI evaluation using routine T1- and T2-weighted sequences, heavily T2-weighted imaging, diffusion-weighted imaging, and dynamic post-contrast sequences provides reliable characterisation of focal liver lesions. MRI is especially valuable in cases where ultrasound or CT findings are indeterminate, in suspected malignant lesions, in cirrhotic liver, and in pre-treatment planning.

Limitations

The present study had certain limitations. First, the sample size was relatively small, with 40 cases, and some lesion subgroups such as cholangiocarcinoma, hydatid cyst, pyogenic abscess, and PCKD-associated hepatic cysts had very few cases. Therefore, diagnostic performance values for these subgroups should be interpreted with caution.

Second, this was a single-centre study conducted over a one-year period, which may limit the generalisability of the findings to larger populations. Third, histopathological confirmation was not available for all benign lesions, as some lesions such as hemangiomas and simple cysts were confirmed by imaging follow-up and clinical correlation. Fourth, hepatobiliary contrast agents and quantitative ADC-based cut-off analysis were not uniformly included in all cases. Finally, interobserver variability was not assessed, as MRI interpretation was not separately analysed between multiple radiologists.

Future Directions

Further studies with larger sample size and multicentric design are recommended to validate the diagnostic accuracy of MRI in different types of focal liver lesions. Future research should include standardised liver MRI protocols incorporating diffusion-weighted imaging, ADC quantification, dynamic contrast-enhanced imaging, and hepatobiliary phase imaging where available.

Use of structured reporting systems such as LI-RADS in patients with cirrhosis or high risk for hepatocellular carcinoma may improve diagnostic reproducibility. Larger studies comparing MRI with CT, ultrasound, contrast-enhanced ultrasound, FNAC, biopsy, and operative histopathology would further strengthen evidence regarding the role of MRI in focal liver lesion characterisation.

Artificial intelligence-based image analysis, radiomics, and quantitative MRI parameters may also have future value in differentiating benign from malignant focal liver lesions, predicting tumour biology, and guiding personalised treatment planning.

Funding

No external funding was received for this study.

Conflict of Interest

The authors declare that there are no conflicts of interest.

Acknowledgement

The authors thank the Department of Radiodiagnosis, Maheswara Medical College &General Hospital, and all patients who participated in the study.

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