Contrast Harmonic Imaging of Canine Hepatic Tumors

Factors associated with survival in dogs with a histopathological diagnosis of hepatocellular carcinoma: 94 cases (2007-2018)

Background:

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer in dogs. Despite this, relatively few reports of this disease exist pertaining to prognostic factors and outcome.

Aim:

To evaluate factors associated with survival in dogs with all subtypes of HCC diagnosed on histopathology.

Methods:

A retrospective single institutional study was carried out on 94 client-owned dogs with a histopathologic diagnosis of HCC between 2007 and 2018 obtained by biopsy (21/94) or attempted definitive resection (73/94). Signalment, preoperative features, surgical findings, and postoperative outcomes were recorded. Associations between survival to discharge data were collected and univariable logistical regression was carried out. Kaplan–Meier survival analysis was carried out to identify negative risk factors for long-term prognosis.

Results:

The median survival time (MST) for all patients was 707 days (95% CI = 551–842). MST was not significantly different (p > 0.05) between patients who had suspected versus incidentally diagnosed HCC (695 vs. 775 days), between complete versus incomplete surgical margins (668 vs. 834 days), or between patients with massive subtype versus nodular/diffuse subtype (707 vs. 747 days). Logistical regression identified an association with the excision of the right medial lobe and risk of perioperative death (OR = 9.2, CI 1.5–55.9, p = 0.016). An American Society of Anesthesiologists score ≥4, disease present within the quadrate lobe, and elevated blood urea nitrogen, potassium or gamma-glutamyltransferase were identified as negative prognosticators during multivariable Cox regression. Preoperative imaging (ultrasound or CT) agreed with the surgical location in 91% of the cases. Preoperative cytology was consistent with a diagnosis of HCC in 15/32 (46.9%) cases.

Conclusion:

Type of diagnosis (incidental vs presumed), completeness of excision, and subtype were not associated with MST in this study. Preoperative identification of tumors within the central division may be related to a less favorable outcome. Results of preoperative cytology were not highly sensitive for identifying a malignancy.

Contrast-enhanced ultrasound features of hepatocellular carcinoma in dogs

Background

This study aimed to describe the contrast-enhanced ultrasound (CEUS) features of canine hepatocellular carcinoma (HCC) in relation to cellular differentiation and lesion size.

Methods

Sixty dogs with a cytological diagnosis of HCC and that underwent a CEUS examination were retrospectively selected. The wash-in and wash-out patterns of contrast enhancement, along with the time to wash-in and the time to wash-out, of each lesion were recorded. A dimensional cut-off value of 3 cm was adopted for classification.

Results

Cellular differentiation had a significant influence on both wash-in (chi-squared=16.99; P<0.001) and wash-out (chi-squared=10.9; P=0.004) patterns of contrast enhancement. Lesion size had a lower, but still significant, influence on both wash-in (chi-squared=12.7; P=0.005) and wash-out (chi-squared=7.42; P=0.024) patterns. A homogeneous hyperenhancement in the arterial phase followed by homogeneous wash-out were suggestive of a well-differentiated HCC. The cellular differentiation of lesions with inhomogeneous hyperenhancement or hypoenhancement/no enhancement as well as an inhomogeneous wash-out or no wash-out could not be inferred.

Conclusions

No significant difference in the time to wash-in and the time to wash-out in relation to cellular differentiation or lesion size was evident. CEUS has the potential to improve efficiency in the diagnosis of HCCs in dogs.

Qualitative and quantitative contrast enhanced ultrasonography of the pancreas using bolus injection and continuous infusion methods in normal dogs

Quantitative contrast enhanced ultrasound is a major breakthrough for ultrasound imaging in recent years. However, contrast enhancement of the pancreas is brief with bolus injection. To assess if continuous infusion of Sonazoid^® can prolong the duration of pancreatic enhancement over bolus injections, eight adult dogs received bolus injection and continuous infusion of Sonazoid^® on separate days. Contrast enhanced ultrasound of the pancreatic parenchyma and proximal descending duodenum was performed, and time intensity curves reflecting tissue perfusions were generated. Perfusion parameters- time to initial upslope, peak time, time to wash-out and peak intensity were calculated and evaluated. Fast wash-in to intense peak, followed by rapid wash-out was observed for time intensity curves of bolus injection. With continuous infusion, contrast wash-in to peak intensity was gradual, followed by long plateau and slow wash-out. Median contrast enhancement durations of the pancreas and duodenum were significantly prolonged by continuous infusion from 11 sec (range, 10 to 23 sec) and 16 sec (range, 3 to 43 sec) at bolus injection to 205 sec (range, 170 to 264 sec, P<0.01) and 193 sec (range, 169 to 216 sec, P<0.05), respectively. Median peak intensity of the pancreas was 100.9 MPV (range, 80.2 to 124.3 MPV) at bolus injection and 77.6 MPV (range, 58.2 to 99.5 MPV, P<0.05) at continuous infusion. Prolonged continuous imaging is afforded by continuous infusion of contrast agent. Peak intensity of the pancreas was slightly diminished in continuous infusion, but offered adequate imaging subjectively.

Contrast-enhanced ultrasonography of the small bowel in healthy cats

We characterized the pattern of ultrasonographic contrast enhancement of the small intestinal wall using a commercial contrast medium (Sonovue(®) ) in 10 healthy awake cats. Subjectively, a rapid intense enhancement of the serosal and submucosal layers was followed by gradual enhancement of the entire wall section during the early phase. At peak enhancement, there was a subjective loss of demarcation between intestinal wall layers. In the late phase, there was a gradual wash out of signal from the intestinal wall. Submucosal wash out occurred last. Time-intensity curves were generated for selected regions in the intestinal wall and multiple perfusion parameters were calculated for each cat. Perfusion parameters included arrival time (7.64 ± 2.23 s), baseline intensity (1.04 ± 0.04 a.u.), time to peak from injection (10.74 ± 2.08 s), time to peak from initial rise (3.1 ± 1.15), peak intensity (8.92 ± 3.72 a.u.), wash-in rate (2.06 ± 0.70 a.u./s) and wash-out rate (-1.07 ± 0.91 a.u./s). The perfusion pattern of normal feline small bowel may be useful for characterizing feline gastrointestinal disorders that involve the intestinal wall.

Quantitative contrast-enhanced ultrasonographic analysis of perfusion in the kidneys, liver, pancreas, small intestine, and mesenteric lymph nodes in healthy cats

OBJECTIVE

To evaluate perfusion of abdominal organs in healthy cats by use of contrast-enhanced ultrasonography.

ANIMALS

10 young healthy anesthetized cats.

PROCEDURES

Contrast-enhanced ultrasonography of the liver, left kidney, pancreas, small intestine, and mesenteric lymph nodes was performed on anesthetized cats.

RESULTS

Typical perfusion patterns were found for each of the studied organs. Differences in perfusion among organs were associated with specific physiologic features. The liver was enhanced gradually and had a more heterogeneous perfusion pattern because of its dual blood supply and close proximity to the diaphragm, compared with other organs. An obvious and significant difference in perfusion was detected between the renal cortex and medulla. No significant differences in perfusion were detected among the pancreas, small intestine, and mesenteric lymph nodes.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that contrast-enhanced ultrasonography can be used in cats to estimate organ perfusion as in other species. Observed differences in perfusion variables can be mostly explained by physiologic differences in vascularity.

Contrast-enhanced ultrasonography (CEUS) in canine liver examination

Ultrasonography is a noninvasive diagnostic tool used to image size, shape, parenchyma and vascularization of various body organs. Unfortunately, the ultrasonographic image is characterized by a low contrast due to similar acoustic properties of the soft tissue. The Doppler mode provides information about blood flow, but is incapable of imaging small vessels and capillaries because of their low blood flow velocity (1 mm/s). However, a possibility to increase the effectiveness of ultrasonographic diagnostics exists, thanks to intravenous ultrasound contrast agents (UCAs) consisted of gas microbubbles. The purpose of this review paper is to characterize specific imaging techniques necessary to conduct a contrast-enhanced liver examination and indications for CEUS as an alternative diagnostic method.

Characterization of canine focal liver lesions with contrast-enhanced ultrasound using a novel contrast agent-sonazoid

Contrast-enhanced ultrasound using Sonazoid, a novel contrast medium with a liver-specific Kupffer phase, was evaluated in canine focal liver lesions Twenty-five dogs with a liver mass were given intravenous Sonazoid, and the enhancement pattern in the arterial, portal, and parenchymal phase was characterized. An enhancement defect in the lesion in the parenchymal phase was observed in all malignant lesions, whereas only one of nine benign lesions had a filling defect. The diagnostic value of the presence of a filling defect for malignancy was statistically significant (100% sensitivity, 88.9% specificity, 94.1% positive predictive value, 100% negative predictive value), and was equal to that of hypoenhancement in the portal or delayed phase. The defect pattern (clear or irregular defect) was dependent (P < 0.05) on the types of malignancy (i.e., hepatocellular carcinoma and other types of malignancies). In the arterial phase, five of the six hepatocellular carcinomas had hypervascularity, whereas no other lesion was characterized by hypervascularity. In some dogs, additional lesions that could not be observed with conventional B-mode ultrasonography were detected in the parenchymal phase. The enhancement pattern of Sonazoid, especially in the parenchymal phase, has potential as a diagnostic tool for canine focal liver lesions.