Can sonographic findings predict the results of liver aspirates in dogs with suspected liver disease?

Histopathologic findings and survival outcomes of dogs undergoing liver lobectomy as treatment for spontaneous hemoabdomen secondary to a ruptured liver mass: retrospective analysis of 200 cases (2012-2020)

OBJECTIVE

To describe the distribution of histopathologic diagnoses in a large population of dogs undergoing surgical treatment for spontaneous hemoperitoneum secondary to a ruptured liver mass. Additionally, to describe survival outcomes and assess for prognostic factors for overall survival time in this population.

ANIMALS

200 client-owned dogs with spontaneous hemoperitoneum resulting from a liver mass.

PROCEDURES

Medical records from 19 veterinary referral hospitals were reviewed. Data collected included signalment, clinical signs, blood work, radiographic and ultrasonographic findings, surgical methods, intraoperative and postoperative complications, outcomes, and histopathologic findings. Follow-up information was obtained by contacting the referring veterinarian or owner.

RESULTS

Well-differentiated hepatocellular carcinoma, benign masses, hemangiosarcoma, and other malignant tumors accounted for 36% (72/200), 27.5% (55/200), 25.5% (51/200), and 11% (22/200) of cases, respectively. Overall survival time for all dogs was 356 days and for the above categories was 897 days, 905 days, 45 days, and 109 days, respectively. Prognostic factors for survival included diagnosis, increased ALT, anemia, and whether a transfusion was received. Overall survival time in dogs with increased ALT was 644 versus 63 days with normal values.

CLINICAL RELEVANCE

The majority of dogs (63.5%) were diagnosed with well-differentiated hepatocellular carcinoma or a benign process, resulting in favorable long-term survival. The distribution of histopathology for ruptured liver masses resulting in hemoperitoneum has not been previously reported and may be useful for client discussions prior to surgery.

Comparative Oncology: Management of Hepatic Neoplasia in Humans and Dogs

Primary hepatic neoplasia is uncommonly reported in dogs. Hepatocellular carcinoma (HCC) is the most frequent neoplasia identified in dogs and considerable effort has been committed towards identifying definitive and palliative treatment options. HCC is well recognized in humans as a sequelae of liver disease such as hepatitis or cirrhosis, while in dogs a similar link has failed to be fully elucidated. Management of HCC in people may be curative or palliative dependent on staging and transplant eligibility. Despite differences in etiology, there is substantial similarity between treatment options for liver neoplasia in human and veterinary medicine. The below summary provides a comparative discussion regarding hepatic neoplasia in dogs and people with a specific focus on HCC. Diagnosis as well as descriptions of the myriad treatment options will be reviewed.

Hypoattenuating periportal halo on CT in a patient population can occur in presence of a variety of diseases

Many pathologies can occur in the periportal space and manifest as fluid accumulation, visible in Computed tomography (CT) images as a circumferential region of low attenuation around the intrahepatic portal vessels, called periportal halo (PPH). This finding is associated with different types of hepatic and extra-hepatic disease in humans and remains a non-specific sign of unknown significance in veterinary literature. The aim of this study was to investigate the prevalence of PPH in a population of patients undergoing CT examination and to assess the presence of lesions related to hepatic and extra-hepatic disease in presence of PPH. CT studies including the cranial abdomen of dogs and cats performed over a 5-year period were retrospectively reviewed. The prevalence of PPH was 15% in dogs and 1% in cats. 143 animals were included and the halo was classified as mild, moderate and severe, respectively in 51%, 34% and 15% of animals. The halo distribution was generalized in 79 cases, localized along the second generation of portal branches in 63, and along the first generation only in one. Hepatic disease was present in 58/143 and extra-hepatic disease in 110/143 of the cases. Main cause of hepatic (36%) and extra-hepatic disease (68%) was neoplasia. Associations between halo grades and neoplasia revealed to be not statistically significant (p = 0.057). In 7% of animals the CT examination was otherwise unremarkable. PPH is a non-specific finding, occurring in presence of a variety of diseases in the examined patient population.

Comparison of fine-needle cytologic diagnosis between the left and right liver lobes of dogs and cats with diffuse liver disease

Background and Aim:

Ultrasound-guided fine-needle sample collection for cytology with manual restraint is frequently used for the primary assessment of diffuse liver disease in veterinary patients in Thailand. For better diagnosis, repeated collection of samples ensures the collection of adequate, representative samples, which increase diagnostic accuracy. However, in those that are unable to receive general anesthesia, it is difficult to collect the samples from several liver locations in manually restrained dogs and cats. The study aimed to compare the cytologic diagnosis of the ultrasound-guided fine-needle non-aspiration technique between the left and right liver lobes in dogs and cats with neoplastic and non-neoplastic diffuse liver disease.

Materials and Methods:

This prospective study included 25 client-owned dogs and cats with diffuse liver diseases. Two liver samples were randomly collected from the left and right liver lobes under ultrasound guidance for cytologic examination. All slides were subsequently examined blindly by experienced pathologists for cytologic analysis with cytologic agreement scores (CASs).

Results:

Among all 50 samples obtained from ultrasound-guided fine-needle sample collection of the left and right liver, 78% were diagnostic and 22% were non-diagnostic. In the diagnostic group, 73.3% of fine-needle samples had concordant results between the left and right liver, which exhibited 100% cytologic agreement in lymphoma and 63.6% in non-neoplastic groups. Samples collected from the left liver had slightly higher CAS and higher cytologic quality than had those from the right liver lobe (p=0.053).

Conclusion:

The location and number of sample collections did not have a significant difference in the cytologic diagnosis of diffuse liver disease, especially in patients with lymphoma. For manually restrained patients, one time ultrasound-guided non-aspiration cytology procedure from the left liver lobe not only decreased restraint duration and minimized tissue trauma but also allowed for an adequate cytologic diagnosis in diffuse liver disease compared to multiple collections.

Morphometric evaluation of canine hepatocellular carcinoma using computed tomography: a promising tool for predicting malignancy

The size of canine focal liver lesions (FLLs) is known to be one of the predicting criteria for malignancy. However, there are discrepancies for the measurement of maximum lesion size, resulting in contradicting results among studies and incidences of false positive outcomes. Thus far, the morphometric changes of FLLs for distinguishing malignancy from benignancy remains undocumented. This study aimed to investigate morphometric characteristics of FLLs using computed tomography (CT). CT images of 40 dogs with histopathological confirmation of 49 liver lesions, including 39 hepatocellular carcinomas and 10 nodular hyperplasias were retrospectively reviewed. The morphometric parameters including size (long and short axis diameters measured on transverse image), shape (measured by long to short axis (L/S) ratio), volume, and surface appearance of a liver lesion were evaluated using univariate and stepwise multivariate analyses, respectively. The results of univariate analysis showed that long and short axis diameters, L/S ratio, volume, and surface appearance of a lesion were significantly different between hepatocellular carcinomas and nodular hyperplasias. Multivariate analysis revealed that short axis diameter (>3.30 cm; odds ratio (OR): 36.1, 95% confidence interval (CI): 3.36–387.05, P=0.0031) and L/S ratio (>1.23; OR: 18.1, 95% CI: 1.61–205.12, P=0.0191) were independent predictors of malignancy, with the area under the curve of 0.9154. These results suggest that the combination of short axis diameter and L/S ratio is a promising tool for predicting liver malignancy with outstanding discriminating ability.

Quantitative ultrasound elastography and serum ferritin level in dogs with liver tumors

Objective:

The objective of this study was to assess the serum ferritin level and quantitate ultrasound elastography as a marker to distinguish dogs with benign and malignant liver tumors.

Materials and Methods:

Twenty-eight dogs were determined the serum ferritin and ultrasound elastography by using fine-needle aspiration biopsy.

Results:

Our results demonstrated that dogs with malignant liver tumors had significantly higher mean serum ferritin concentrations than those with benign liver tumors (p = 0.004). The mean intensity of blue and red colors from elastography was greater in the malignant than those in the benign group, especially for the blue color, meaning that lesions showed more hard tissue. Additionally, histograms of blue color in the malignant tended to be higher than the benign group.

Conclusion:

We suggested that quantitative ultrasound elastography and serum ferritin concentration comprise an alternative and non-invasive diagnostic method that could be used to predict the type of liver tumors in dogs.

Computed tomographic features for differentiating benign from malignant liver lesions in dogs

Thus far, there are few computed tomography (CT) characteristics that can distinguish benign and malignant etiologies. The criteria are complex, subjective, and difficult to use in clinical applications due to the high level of experience needed. This study aimed to identify practical CT variables and their clinical relevance for broadly classifying histopathological diagnoses as benign or malignant. In this prospective study, all dogs with liver nodules or masses that underwent CT examination and subsequent histopathological diagnosis were included. Signalments, CT findings and histopathological diagnoses were recorded. Seventy liver nodules or masses in 57 dogs were diagnosed, comprising 18 benign and 52 malignant lesions. Twenty-three qualitative and quantitative CT variables were evaluated using univariate and stepwise multivariate analyses, respectively. Two variables, namely, the postcontrast enhancement pattern of the lesion in the delayed phase (heterogeneous; odds ratio (OR): 14.7, 95% confidence interval (CI): 0.82–262.03, P=0.0429) and the maximal transverse diameter of the lesion (>4.5 cm; OR: 33.3, 95% CI: 2.29–484.18, P=0.0006), were significantly related to the differentiation of benign from malignant liver lesions, with an area under the curve of 0.8910, representing an accuracy of 88.6%. These findings indicate that features from triple-phase CT can provide information for distinguishing pathological varieties of focal liver lesions and for clinical decision making. Evaluations of the maximal transverse diameter and postcontrast enhancement pattern of the lesion included simple CT features for predicting liver malignancy with high accuracy in clinical settings.

A randomised controlled comparison of aspiration and non-aspiration fine-needle techniques for obtaining ultrasound-guided cytological samples from canine livers

Ultrasound-guided fine-needle sampling to obtain cytological samples is a well-established technique. However, the application of suction during sampling is controversial. Evidence from the human literature and one previous veterinary study suggest that non-aspiration may be superior for a number of organs. This prospective study compared the quality and diagnostic value of cytological samples from canine livers obtained by fine-needle aspiration (FNA) and non-aspiration (FN-NA) techniques. A total of 119 dogs that required ultrasound-guided FNA of the liver as part of their clinical investigation were recruited and randomly assigned to either FNA (n=54) or FN-NA (n=65) sampling groups. Specimens were reviewed by external cytopathologists masked to the technique used. Cytological reports were reviewed for their overall diagnostic value, cellularity, cell preservation and haemodilution. Overall, 88.2% (95% confidence intervals [CI], 82.4-94.0) of samples were diagnostic. There was a significant difference, as demonstrated by Chi-squared statistical analysis, in the prevalence of diagnostic samples between the FNA (81.5%; 95% CI, 71.1-91.8) and FN-NA groups (93.9%; 95% CI, 88.0-99.7; P=0.037). Non-diagnostic samples were significantly associated with lower cellularity, poorer cell preservation and more severe haemodilution (P<0.001 for each). However, there were no significant differences in the frequency of these specific variables between the FNA and FN-NA groups. In this study, fine-needle non-aspiration was superior to an aspiration technique for sampling the canine liver, as it resulted in higher rates of diagnostic cytology samples, with greater cellularity, less haemodilution and better cytological preservation.

Predictive factors of malignancy in dogs with focal liver lesions using clinical data and ultrasonographic features

A definitive diagnosis of focal liver lesions (FLLs) requires invasive procedures for histopathologic examination. Thus, a simpler noninvasive diagnostic method, such as conventional ultrasonography combined with clinical data, is needed for the prediction of liver malignancy. The objective of this study was to examine the diagnostic accuracy of clinical data and ultrasonographic (US) features to differentiate benign and malignant liver lesions. Medical records and US images from dogs with FLLs that underwent abdominal US and histopathologic examinations following surgery or liver biopsy were retrospectively reviewed. Clinical data, including signalment, clinical signs and laboratory findings, and the US features of liver lesions that could act as predictive factors were assessed using univariate and multivariate analyses to evaluate the associations between predictive factors and liver malignancy. Based on the histopathologic results, 55 dogs with malignant lesions and 28 dogs with benign lesions were included in the study. The results of univariate analysis showed that several US features and platelet count were significantly associated with liver malignancy. Multivariate analysis revealed that the platelet count (thrombocytosis; odds ratio [OR]: 4.13, 95% confidence intervals [CI]: 1.81−9.41), lesion size (4.1 cm or greater; OR: 23.83, 95% CI: 3.74−151.95) and echotexture of FLLs (heterogenous; OR: 8.44; 95% CI: 1.37−51.91) were independent predictors for differentiating benign and malignant liver lesions, suggesting that a combination of clinical data and US findings of FLLs could predict liver malignancy in dogs.

Non-invasive quantification of hepatic fat content in healthy dogs by using proton magnetic resonance spectroscopy and dual gradient echo magnetic resonance imaging

The objective of the present study was to describe two non-invasive methods for fat quantification in normal canine liver by using magnetic resonance imaging (MRI) and spectroscopy. Eleven adult beagle dogs were anesthetized and underwent magnetic resonance examination of the cranial abdomen by performing morphologic, modified Dixon (mDixon) dual gradient echo sequence, and proton magnetic resonance spectroscopy (¹H MRS) imaging. In addition, ultrasonographic liver examination was performed, fine-needle liver aspirates and liver biopsies were obtained, and hepatic triglyceride content was assayed. Ultrasonographic, cytologic, and histologic examination results were unremarkable in all cases. The median hepatic fat fraction calculated was 2.1% (range, 1.3%-5.5%) using mDixon, 0.3% (range, 0.1%-1.0%) using ¹H MRS, and 1.6% (range 1.0%-2.5%) based on triglyceride content. The hepatic fat fractions calculated using mDixon and ¹H MRS imaging were highly correlated to that based on triglyceride content. A weak correlation between mDixon and ¹H MRS imaging was detected. The results show that hepatic fat content can be estimated using non-invasive techniques (mDixon or ¹H MRS) in healthy dogs. Further studies are warranted to evaluate the use of these techniques in dogs with varying hepatic fat content and different hepatic disorders.

GADOXETATE DISODIUM (GD-EOB-DTPA) CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF HEPATOCELLULAR CARCINOMA IN DOGS

Hepatocellular carcinoma is the most common primary hepatic tumor in dogs and is amenable to surgical resection in many cases. Unfortunately, overlap of sonographic findings between benign and malignant hepatic lesions typically requires more invasive diagnostic tests to be performed (e.g., biopsy for histopathology). The availability of a noninvasive diagnostic test to identify hepatocellular carcinoma would be beneficial. The use of a liver-specific magnetic resonance imaging (MRI) contrast agent such as gadoxetate disodium (Gd-EOB-DTPA; Eovist® or Primovist®) has improved lesion detection in human patients. In this descriptive study, gadoxetate disodium contrast-enhanced MRI characteristics in dogs were evaluated in seven dogs (total of eight lesions). The imaging characteristics were variable with the exception of all lesions being hypointense to surrounding normal hepatic parenchyma on 3D T1-weighted gradient recalled echo images at all postcontrast time points. All lesions displayed signal intensity ratios less than 1, consistent with retained but impaired hepatocyte function. Hepatic lesions not identified on previous imaging were found in 3/7 patients which may affect surgical planning. In two patients, several hepatic nodules were identified during surgery which had not been visualized on MRI and were found to be benign on histopathology. This descriptive study reports the MRI characteristics of hepatocellular carcinoma in dogs using the liver-specific contrast agent gadoxetate disodium.

Total serum bilirubin as a negative prognostic factor in idiopathic canine chronic hepatitis

Total serum bilirubin (TBIL) is used as a prognostic factor in chronic hepatitis (CH) in human beings. To date, the authors are unaware of any studies looking at the value of TBIL as a prognostic factor in idiopathic canine CH. The objective of the current study was to assess if TBIL is a negative prognostic factor in idiopathic canine CH, and to identify other prognostic factors. Thirty-nine dogs with histologically confirmed idiopathic CH admitted to 2 referral centers between 1999 and 2010 were included in the study. Patients with concurrent diseases that could affect TBIL or the survival time were excluded. Total serum bilirubin was measured prior to liver biopsy, and CH was diagnosed according to standardized histological criteria. Survival time was calculated from time of diagnosis to time of death or euthanasia. Cox proportional hazard analysis was performed to identify prognostic factors. The mean survival time for the 39 dogs included in the analysis was 197 days (1-2,677), and the mean total serum bilirubin was 11 μmol/l (2-265). Total serum bilirubin was statistically significantly associated with survival (odds ratio = 1.082, P = 0.047) as were weight (odds ratio = 1.028, P = 0.028) and the presence of ascites (odds ratio = 6.758, P = 0.013). The current study demonstrates that TBIL could be used as an additional prognostic factor in canine CH.

A comparison of hepatic sonographic features and histopathologic diagnosis in canine liver disease: 138 cases

BACKGROUND

Ultrasound examination is commonly used in the diagnostic evaluation of liver disease in dogs.

HYPOTHESIS/OBJECTIVES

To determine if hepatic sonographic features were predictive of findings on liver histopathology. We hypothesized that there would be a relationship between sonographic features and the category of liver disease based on histologic assessment.

ANIMALS

One hundred and thirty-eight dogs in which the liver was evaluated by both abdominal ultrasound examination and histopathologic examination. Twenty-five dogs were included in each of the following categories based on histopathology: normal, degenerative, vascular, inflammatory, and neoplasia. Thirteen dogs had nodular regeneration.

METHODS

Retrospective study. Medical records of dogs from 2005 to 2010 were searched for cases in which the liver was evaluated by abdominal ultrasound examination as well as by histopathology. After independent evaluation of ultrasound images, the recorded sonographic features were analyzed to identify abnormalities associated with each histopathologic diagnosis or degree of fibrosis.

RESULTS

Sixty-four percent of sonographically unremarkable livers had histologic abnormalities. Both microhepatia and the identification of abnormal vasculature were significantly associated with a histopathologic diagnosis of vascular disease. Hepatic masses were significantly associated with a diagnosis of neoplasia. Dilated common bile duct and thickened gall bladder wall were significantly associated with hepatitis. There were no sonographic findings consistently present with hepatic fibrosis.

CONCLUSION AND CLINICAL IMPORTANCE

Although some ultrasonographic findings, including masses, microhepatia, anomalous veins, and biliary changes, are associated with specific histopathologic abnormalities, sonographic findings are inconsistently detected in many disorders. Overall, hepatic ultrasonographic abnormalities have substantial limitations in predicting the underlying disease.

Accuracy of US-Guided FNA of Focal Liver Lesions in Dogs: 140 Cases (2005–2008)

Medical records from dogs having abdominal ultrasound (US) performed between March 2005 and October 2008 were reviewed for detection of focal liver lesions (FLL) with both cytologic and histologic sampling. Samples were classified as to either the presence or absence of major categories of pathologic processes, including malignant neoplasia, inflammation, hyperplasia/benign neoplasia, vacuolar change, extramedullary hematopoeisis, cholestasis, necrosis, and no microscopic abnormalities. Evaluation of selection bias was performed by review of the relative distribution of cytologic diagnoses for cases with histology compared with cases excluded from the comparison analysis because histology results were not available. Cytology had the highest sensitivity for vacuolar change (57.9%), followed by neoplasia (52.0%). Cytology had the highest positive predictive value (PPV) for neoplasia (86.7%) followed by vacuolar change (51.6%). Cytology had lower sensitivity and PPVs for inflammation, necrosis, and hyperplasia. The ability of cytology to characterize disease in canine FLL varies by pathologic process. Clinicians can have a high degree of confidence when a cytologic diagnosis of neoplasia is given; however, cytology is less reliable for excluding the potential for neoplasia. Cytology has a low sensitivity and PPV for inflammation and a limited diagnostic performance for the diagnosis of vacuolar change.

Analysis of clinical and ultrasonographic data by use of logistic regression models for prediction of malignant versus benign causes of ultrasonographically detected focal liver lesions in dogs

OBJECTIVE

To investigate the value of clinical, laboratory, and imaging data for use in predicting malignant or benign histologic results for ultrasonographically detected focal liver lesions in dogs.

SAMPLE

Records and archived images of 247 dogs evaluated at the University of Minnesota Veterinary Medical Center from 2005 to 2008 that underwent abdominal ultrasonography and histologic evaluation of the liver.

PROCEDURES

Data were analyzed with multivariable logistic regression models. All dogs were classified as having benign or malignant liver disease on the basis of histologic reports. Three multivariable logistic regression models were fit to a development subset of the data by use of combinations of signalment, historical, physical examination, laboratory, and diagnostic imaging (survey radiography and abdominal ultrasonography) data as predictor variables. The resulting models were validated by evaluating predictive performance against a holdout validation subset of the data.

RESULTS

Models that included ultrasonographic variables had the highest overall predictive value. In these models, greater lesion size and the presence of peritoneal fluid were the only variables that had a positive association with malignant liver disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Large ultrasonographically detected liver lesions and the presence of peritoneal fluid were associated with malignant liver disease in dogs.

Getting to the point: indications for fine-needle aspiration of internal organs and bone

The technique of fine-needle biopsy (fine-needle aspiration or fine-needle fenestration) for cytologic evaluation can be extended to many sites beyond the traditional lymph node and skin. Intra-abdominal, intrathoracic, and bone lesions can be easily and rapidly evaluated cytologically. Percutaneous fine-needle aspiration and fine-needle fenestration are useful, accurate, and inexpensive techniques with a rapid turnaround time, and outpatient applicability. For most pets, these minimally invasive techniques do not require anesthesia or analgesia. Although risks are inherent with any invasive procedure, complications are uncommon even with visceral and intrathoracic fine-needle biopsy. Attention to appropriate technique and close patient monitoring minimize the morbidity and improve the diagnostic utility. The low cost, low risk, minimal invasiveness, and high diagnostic yield make fine-needle biopsy particularly attractive to clients. In combination with ultrasound guidance and newer staining techniques, these diagnostic procedures are invaluable to the veterinary clinician.