THE ROLE OF ULTRASOUND-GUIDED BIOPSY IN T HE DIAGNOSIS OF HEPATIC DISEASES OF DOGS AND CATS

A retrospective study was performed including 13 dogs and 3 cats with hepatic diseases to assess the technique and diagnostic capability of ultrasound-(US) guided liver biopsy. The presence of liver disorder we re suggested according to the results of physical el;amination and the laboratory analysis of the following blood parameters: haemoglobin, P CV, activities of ALT, GGT and A, as well as clotting, bleeding and pr othrombin time. After evaluation of the US appearance of the liver and gallbladder (Fig. 1), and checking the parameters of blood coagulatio n, US-guided biopsy were done on the animals in moderate neuroleptanal gesia. The latter was achieved with i.v. xylazine-ketamine in dogs and with ketamine-diazepam in cats. US examination was done with 5 and 7 MHz mechanical sector transducers, attached to a Type 1836 Bruel and K jaer ultrasound system (Naerum, Denmark). Biopsy was performed with a semiautomatic biopsy needle (Type Acecut, size: 16 or 18 G, TSK Labora tory, TOCHIMBRI SEIKO, Japan). The biopsy needle was directed to the d esired place of the liver under visual US-guidance (Fig. 2) and using the free-hand technique for needle manipulation. Immediate and 24 hour s postbiopsy US examination and clinical observation served to detect potential complications. Proper biopsy sample were gained on the first biopsy attempt in 11 dogs and 3 cats, and in 2 dogs on the second att empt. Postbiopsy complications were observed in none of patients. Tabl e 1 shows the ultrasonographic and histological results. Liver enlarge ment were seen in 14 and small liver in 2 patients, respectively. Simu ltaneous dilatation of the gallbladder and bile retention were observe d in 5 animals. In one cat (case 10) both ultrasonography and biopsy h istology were negative despite of the clinicolaboratory findings which suggested the presence of liver disorder. Multifocal US-changes were detected in 3 cases, all thought to be hepatic neoplasms as to the US appearance (cases 8, 13, and 15). On the contrary, biopsy histology re vealed subacute hepatitis in case 8, periportal cyst in case 13 and on ly in case 15 was the ultrasonographically diagnosed neoplasm confirme d as hepatocellular carcinoma (Fig. 3). Diffuse US-alterations were se en in 12 animals. In 6 of these patients, ultrasound diagnoses corresp onded basically to the histological findings. Cases 1 and 2: hepatic l ipidosis, cases 3, G, and 7: hepatosis/hepatitis, case 16: bepatic cir rhosis. In case 12, hepatosis or the presence of hepatic neoplasm coul d not be differentiated ultrasonographically and histology confirmed h epatosis. In five animals with diffuse US-changes, the ultrasound diag nosis differed basically from the histological diagnosis: case 4: hepa tosis or neoplasm (US) chronic, encapsulated haematoma (histology). Ca se 5: diffuse hepatosis (US) - negative (histology); case 9: diffuse l iver alteration (US) - reticulosarcoma (histology); case 14: hepatosis or hepatitis (US) - myeloid dysplasia (histology); case 11: hepatosis (US) - diffuse, pathological simple fatty infiltration of the liver ( Fig. 4). Summarizing these results, it can be concluded that liver US alone was enough only in about 50% of the cases to achieve a clinicall y satisfying diagnosis. US-guided biopsy can be performed safely and i s always necessary if US-results alone are questionable and prognosis and treatment request an accurate in vivo diagnosis.