Origi na l A r tic le Real Time Ultrasonography Evaluation of Focal Liver Lesions: A Cross-sectional Study S Gopalakrishnan1, Sethurajan2, Adaikappan3, Palanisamy Gunasekaran2, R Vivek1 Post-Graduate Student, Department of Radiology, Rajah Muthiah Medical College and Hospital, Chidambaram, Tamil Nadu, India, 2Assistant Professor, Department of Radiology, Rajah Muthiah Medical College and Hospital, Chidambaram, Tamil Nadu, India, 3Associate Professor, Department of Radiology, Rajah Muthiah Medical College and Hospital, Chidambaram, Tamil Nadu, India 1 Corresponding Author: Dr. S. Gopalakrishnan, No. 3, 6th Cross Street, Jaya Nagar, Tiruvallur - 602 001, Tamil Nadu, India. Phone: +91-8939228976. E-mail: [email protected] Abstract Introduction: Focal liver lesions can be congenital or acquired and may be benign or malignant. Sonography, in spite of the advent of advanced imaging modalities has prevailed as the preferred modality for evaluation of liver lesions as it is readily accessible, cost effective and allows real time evaluation. Aim: To establish the efficacy of the diagnostic ultrasound to detect various focal liver lesions and provide necessary information, aiding their appropriate management. Materials and Methods: Patients, who are referred for sonography at Radiology Department, clinically suspected of having focal hepatic lesions with clinical features like abdominal pain, fever, loss of weight and appetite, mass per abdomen, jaundice, abdominal distension and urticaria were included in this study. Results: Ultrasonography is highly sensitive and specific in the diagnosis of focal liver lesions like hemangioma, fatty liver, cirrhosis, cystic and hydatid lesions, malignant liver tissue and metastasis. Conclusion: Ultrasonography is a safe and effective method of detecting focal liver lesions. It’s easy availability, portability, flexibility, lack of dependence on organ function and lack of ionizing radiation makes it ideal for imaging the liver. Keywords: Carcinomas, Cyst, Doppler, Hemangioma, Ultrasonography INTRODUCTION Focal liver lesions are common on pathologic or imaging evaluation of the liver and include a variety of malignant and benign neoplasms, as well as congenital and acquired masses of inflammatory and traumatic nature. Evaluation of focal liver lesions is a complex issue which is often the major focus of the cross sectional imaging study.1 Sonography is widely accessible, relatively inexpensive, portable, noninvasive, nonionizing, allows imaging in multiple planes and can frequently be repeated. It assists in real time evaluation of organ under examination, especially the liver which is situated just below the ribcage without intervening gas, has a high sensitivity and reasonable specficity.2 Sonography has excellent spatial and contrast resolution,3 hence gray-scale morphology of a mass allows for differentiation of cystic and solid masses and in many instances, characteristic recognized appearances may suggest the correct diagnosis without further evaluation. Characterization of a liver mass on conventional sonography is based on the appearance of the mass on gray scale imaging.4 MATERIALS AND METHODS A prospective study of 40 cases of focal liver lesions diagnosed by ultrasonography in Department of Radiodiagnosis. Inclusion Criteria Patients in the age group above 18 years and focal liver lesion of diameter >10.0 mm. Exclusion Criteria Patients with diffuse liver disease like steatosis, cirrhosis, hepatitis, storage diseases. Diffuse malignancies and also the post-operative and post-traumatic patients. International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 64 Gopalakrishnan, et al.: Focal Liver Lesions Sonography Patient Preparation and Scanning Technique Once the patient agrees to participate in the study, informed consent was taken prior to ultrasound examination, followed by detailed history and brief clinical examination. Patients were kept nil by mouth for few hours prior to ultrasound examination. In some cases, clinical condition of the patient demanded an ultrasound examination without prior preparation. 30 25 25 22.5 15 12.5 5 5 0 2.5 18-20 RESULTS In our study, Out of 40 patients, the youngest patient was 19 years of age and the oldest was 84 years of age with a mean age of 52 years. Majority of the patients were in the age group between 50 and 60 years (Table 1 and Graph 1). Out of the 40, majority were males who numbered 26 (65%) and 14 (35%) were females with the male to female ratio being 1.8:1 (Table 2 and Graph 2). Out of the 40 patients, 24 (60%) patients had abdominal pain. 18 (45%) patients had fever, 16 (40%) had loss of weight and appetite, 14 (35%) patients complained of mass per abdomen, 9 (23%) had jaundice and 7 (18%) patients complained of abdominal distension and urticaria. Out of 40 patients, 10 (25%) had hemangiomas 65 21-30 31-40 41-50 51-60 61-70 >70 Graph 1: Age distribution of focal liver lesions Liver was scanned in various planes like sagittal, parasagittal, transverse, oblique, subcostal, intercostal and coronal planes. Comprehensive scanning of other upper abdominal organs was done. Apart from the above observations related to lesion several other important observations were made which include the overall assessment of liver size, portal and hepatic veins involvement, biliary tract and gall bladder, lymphadenopathy and ascites. 10 10 Patients were examined in the supine position to begin with and then in decubitus (right or left) and sitting position if needed. Various ultrasonographic features of focal liver lesions were observed, which include: 1. Number of lesions - Single or multiple 2. Location within liver - Lobar distribution (right lobe, left lobe, both lobes) 3. Echogenicity - (by comparing with that of normal liver parenchyma), Hyperechoic, hypoechoic, anechoic or mixed echogenic 4. Size, shape and margins: Exact size of the lesion was measured with a note on shape of the lesion like round, oval or irregular. Margins of lesion were studied whether well-defined, poorly defined, regular or irregular 5. Acoustic characteristics of lesions. 22.5 20 35 Male 65 Female Graph 2: Sex distribution of focal liver lesions Table 1: Age distribution of focal liver lesions Age group (years) Number of cases Percentage 1 2 5 9 10 9 4 105 2.5 5 12.5 22.5 25 22.5 10 100 18-20 21-30 31-40 41-50 51-60 61-70 More than 70 Total Table 2: Sex distribution of focal liver lesions Sex Male Female Total Number of cases Percentage 26 14 40 65 35 100 and male to female ratio of 1:1.8 (Table 3 and Graph 3), which is in close correlation to the study of Gandolfi et al.5 and Trastek et al.6 However this is lower than reported by the other workers who noted a female prevalence up to 5:1,7,8 8 (20%) had metastases. It was most commonly seen in the age group of 51-60 years (Graph 4). The age group ranged from 51 to 68 years with a mean age of 58.2 years. Males constituted majority (75%) and females the remainder, 7 (17.5%) had abscess the age group was in the range of 1962 years with a mean age of 47 years. Hepatic abscess was predominantly seen in males 6 (85.7%) and 1 (14.3%) female patient. Male to female ratio was 6:1. 6 (15%) had cystic lesion International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 Gopalakrishnan, et al.: Focal Liver Lesions Sonography Table 3: Sex distribution of individual focal liver lesions Sex Male Female Total Liver abcess PMLT Metas tases Hemangioma Cystic lesion Hydatid lesion Cholangiocarcinoma Total 6 1 7 4 1 5 6 2 8 5 5 10 3 3 6 2 1 3 1 1 26 14 40 PMLT: Primary malignant liver tumor 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 1 DISCUSSION 1 2 5 6 3 1 Haemangioma 1 4 6 5 3 2 Female Male Graph 3: Sex distribution of individual focal liver lesions It is the most common benign liver lesion, cavernous type with incidence ranging from 0.4% to 20%. Common in females ratio being 5:1. Sonography Typically the lesions are small, <3 cm in diameter, well defined, homogenous and hyperechoic (Figure 1). Increased echogenicity has been related to numerous interfaces between the walls of the cavernous sinuses and the blood within them. Larger lesions tend to be heterogeneous with central hypoechoic foci corresponding to fibrous collagen scars. Color Doppler Hemangiomas are characterized by extremely slow blood flow, which is imperceptible. Hepatic Adenoma They are benign, well encapsulated; true hepatic neoplasms composed entirely of hepatocytes. These are solitary tumors occurring predominantly in women of child bearing age and is strongly associated with use of oral contraceptives. Graph 4: Age distribution of individual focal liver lesions in the age group of 36-75 years with a mean age of 48.3 distributed equally in both males and females as compared to previous study which showed female preponderance,9 5 (12.5%) had primary malignant liver tumor with age range of 49-84 years, with a mean age of 66.8 years. These were more common in 61-70 years. Majority of the patients were males 4 (80%) and 1 (20%) female, 3 (7.5%) had hydatid cyst in the age group of 28-54 years of age with a mean age of 38.6 years. Males were the predominant group compromising 2 (66.6%) and 1 (33.3%) female patient, and 1 (2.5%) had cholangiocarcinoma in a female aged 75 years (Table 4). Diagnosis of hemangioma, cystic and hydatid lesions showed specificity of 97.8%, 98.9% and 98.9% respectively. In 28 (70%) patients the lesions were in the right lobe, in 7 (17.5%) involved both lobes and in 5 (12.5%) in the left lobe. In 30 (75%) patients had solitary lesions and 10 (25%) had multiple lesions. Sonography An echogenic mass with halo is one of its presentations (Figure 2), but adenomas may be hypoechoic, isoechoic or mixed. With hemorrhage, a fluid component may be evident within or around the mass and free intra-peritoneal blood may be seen. Compression of the surrounding liver may cause a hypoechoic halo.10 Focal Nodular Hyperplasia (FNH) It is a benign congenital hamartomatous vascular malformation or reparative process in areas of focal injury characterized by a central fibrous scar surrounded by nodules of hyperplastic hepatocytes and small bile ductules. Common in women of reproductive age group.11 Sonography These lesions are typically a well circumscribed, most often solitary mass with a central scar, subtle contour abnormalities and displacement of vascular structures. Lesions may be hypo, is or hyperechoic homogeneous mass International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 66 Gopalakrishnan, et al.: Focal Liver Lesions Sonography Table 4: Age distribution of individual focal liver lesions Age group (years) 18-20 21-30 31-40 41-50 51-60 60-70 >70 Total Liver abscess PMLT Metas tatses Hemangioma Cyti lesion Hydatid lesian Cholangiocarcinoma Total 1 1 1 2 5 9 10 9 4 40 1 1 2 1 2 7 5 3 1 1 4 2 2 8 10 1 2 2 5 1 1 2 2 1 1 1 6 3 PMLT: Primary malignant liver tumor Figure 3: Focal nodular hyperplasia Figure 1: Hemangioma Doppler confi rms mainly arterial signals within the FNH lesion. Simple Liver Cyst It is the second most common benign hepatic lesion, incidence being 22%. Although the cyst is thought to be of congenital, developmental origin, usually, it is discovered in adults more frequent in women with the size varying from 1.0 cm to >20.0 cm in diameter. Sonography Simple hepatic cysts are anechoic with a well demarcated, thin wall and posterior acoustic enhancement (Figure 5).12 Polycystic Liver Disease lesions. Central scar is seen as hypoechoic linear or stellate area within the central portion of the mass (Figure 3). In patients with polycystic liver disease, hepatic tissue surrounding the cysts is not normal and commonly contain Von Meyenburg’s complexes and increased fibrous tissue. Hepatic involvement occurs in approximately 57-74% of patients with autosomal dominant (adult) polycystic kidney disease.13 Color Doppler Sonography FNH is extremely hyper vascular with a dominant feeding artery and stellate vascular pattern. Spectral When more than 10 cysts are present, the diagnosis of polycystic disease should be considered.14 Hepatic cysts are Figure 2: Hepatic adenoma 67 International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 Gopalakrishnan, et al.: Focal Liver Lesions Sonography anechoic with a well demarcated, thin wall and posterior acoustic enhancement (Figure 4). Hepatocellular Carcinoma (HCC) It is one of the most common malignant tumors and one of the 10 most common cancers in the world. It peaks in 5th 6th decade. It occurs predominantly in men, with sex ratio of about 2.5:1. Several growth patterns appear; most common is of the trabecular pattern. Grossly three major patterns of growth are 1. A large solitary mass 2. Nodular or multifocal masses 3. Diffuse or cirrhotomimetic HCC. Sonography The masses may be hypoechoic, complex or echogenic. Most small (<5.0 cm) HCC’s are hypoechoic, corresponding to solid tumor. A thin peripheral halo corresponding to the fibrous capsule is seen most often in small HCC. Calcification is uncommon. HCC of mixed echogenicity is due to non-liquefactivenecrosis (Figure 6). Color Doppler HCC has characteristic high velocity signals (>250 cm/s). Doppler is excellent in detecting neovascularity within tumor thrombi within the portal veins, diagnostic of HCC.15 Fibrolamellar Carcinoma (FLC) Most commonly seen in younger patients. The alphafetoprotein body inclusions that are, usually, seen in HCC are absent in FLC. A fibrous central scar is seen in larger lesions.16 Grossly, FLC, usually, arises in the normal liver; only 20% of patients have cirrhosis. It has more potential for cure (40%) after surgical resection.17 Sonography The echogenicity of FLC is variable. Punctuate calcification and central echogenic scar are common than in hepatomas. Intrahepatic Cholangiocarcinoma An adenocarcinoma that originates in the second or higher order intra hepatic ducts represents 10% of all cholangiocarcinomas. The tumors are large, firm with abundant fibrous tissue. Figure 4: Polycystic liver disease Sonography Hypovascular solid mass with heterogeneous echotexture, may appear hypo, iso or hyperechoic. Has a higher incidence of ductal obstruction (31%) than HCC (2%).18 Figure 5: Simple liver cyst International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 Figure 6: Hepatocellular carcinoma 68 Gopalakrishnan, et al.: Focal Liver Lesions Sonography Metastatic Disease It is the most common malignancy of the non-cirrhotic liver. The highest percentages of liver metastases occur in primary carcinomas of gall bladder, pancreas, colon, stomach and breast.19,20 Most metastases to the liver are blood-borne via the hepatic artery or portal vein. Lesions may be infiltrative, expansile or military. A zone of venous stasis may be observed to surround a metastatic lesion, extending up to 1 cm, in approximately 25% of patients. Tumor thrombi that occlude the portal or hepatic vein may be seen in approximately 7-15% of patients with hepatic metastatic disease. Diagnostic challenges in the radiologic evaluation of metastatic disease include staging and follow-up in patients with a known malignancy and the evaluation of resectability in patients with solitary or few metastases. Sonography identified in metastases from the bronchogenic carcinoma. Calcified metastases are distinctive by virtue of their marked echogenicity and distal acoustic shadowing. Mucinous adenocarcinoma of the colon is the most common primary associated with it.21 Cystic metastases are uncommon, usually, have mural nodules, thick walls, fluid-fluid levels and internal septations. Infectious Lesions Bacterial (pyogenic) liver abscess The liver abscess most commonly develops via the biliary tree, secondary to ascending cholangitis from benign or malignant biliary obstruction.22,23 In adults, Escherichia coli is most commonly isolated, while Staphylococcus is most often isolated from pediatric liver abscess.24,25 More commonly they present with multiple focal liver masses. Sonographic appearances vary like; echogenic, hypoechoic, target, calcified cystic and diffuse. Leucocytosis elevated serum alkaline phosphatase, hypoalbuminemia and prolonged prothrombin time are the most common laboratory findings.26 Echogenic metastases (Figure 7) tend to arise from the gastrointestinal primary or from HCC. More vascular the tumor, more likely the lesion to be echogenic. Therefore, metastases from the renal cell carcinoma, carcinoid, choriocarcinoma and islet cell carcinoma tend to be echogenic. Abscesses from the portal vein sources are often solitary, with 65% occurring in the right lobe, 12% in the left lobe and 23% in both lobes. Hypoechogenic metastases are generally hypovascular and hypercellular without interstitial stroma. Typically seen in untreated breast and lung cancer, as well as gastric, pancreatic and esophageal tumors. Lymphomatous involvement of the liver also manifest as hypoechoic masses. Target or bulls eye pattern is characterized by a peripheral hypoechoic zone. It is nonspecific, although frequently Sonography Frank purulent abscess appear cystic, with the fluid ranging from echo free to highly echogenic. Regions of early suppuration appear solid with altered echogenicity, usually, hypoechoic related to necrosis. Well-defined round lesion with echogenic rim, fluid-fluid interfaces, internal septations, internal debris and gas artifacts. Distal acoustic enhancement is also seen. Fungal Abscess Fungal microabscesses of the liver occur in immun ocompromised patients, most commonly those with hematologic malignancies. Candidiasis, the most common frequently occurring systemic fungal infection in immunocomprosied patients, is most occurring with the increase in the incidence of AIDS and bone marrow transplantation, chemotherapy and radiation therapy. Detection may be difficult because blood cultures are positive in only 50% of patients.27 Sonography Figure 7: Metastasis 69 Sonographic features include - “Wheel within a wheel” due to peripheral hypoechoic zone with an inner echogenic wheel and central hypoechoicnidus. Seen early in the disease. International Journal of Scientific Study | October 2014 | Vol 2 | Issue 7 Gopalakrishnan, et al.: Focal Liver Lesions Sonography Bull’s eye: 1-4 cm lesion having a hyperechoiccentre and a hypoechoic rim. Uniformly hypoechoic: Most common finding, corresponds progressive fibrosis. Echogenic: Variable calcification representing scar formation. Amoebic Abscess Hepatic infection by the parasite entamoebahistolytica is the most common extraintestinal manifestation of amoebiasis.28-30 The parasite crosses the colonic mucosa and enters the portal circulation (most commonly) or the lymphatics or when it passes directly into the liver from the hepatic flexure.31 The preferential occurrence of these lesions in the right lobe is related to the venous drainage.32 Sonography Round or oval shaped lesion with absence of a prominent wall, hypoechogeni city compared to normal liver, fine low-level internal echoes, distal sonic enhancement and contiguity with the diaphragm (Figure 8). Echinococcal Disease Hydatid disease of the liver has two forms i.e. the cystic form and alveolar form. The cysts may be solitary or multiple, grow slowly to reach a large size. The wall of the cyst contains three layers: (1) The pericyst, (2) the endocyst and, (3) the ectocyst. Calcification of the ectocyst alone may occur and when the parasite dies, the true cyst wall (both the ectocyst and endocyst) may also calcify or may separate from the pericyst. Most complications from hydatid cysts are related to rupture of the cyst into surrounding structures (biliary tree, pleura and peritoneum).33,34 Sonography Sonographic features of hepatic hydatid disease are 1. Simple cysts containing no internal architecture except sand 2. Cysts with detached endocyst secondary to rupture 3. Cysts with daughter cysts matrix (echogenic material between the daughter cysts), or both densely calcified masses.35 CONCLUSION Ultrasound showed the highest specificity for hydatid cysts, cystic lesions, hemangioma. Besides the advantages of ultra-sonogram over other modalities with cost effectiveness and accessibility, the introduction of microbubble contrast agents and the development of contrast-specific techniques have opened new possibilities in liver imaging. 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