The aim of this literature review was to present the novel imaging modalities elastography and contrast-enhanced ultrasonography. We provided an overview of the concepts and applications of each technique for the investigation of neoplastic and metastatic tumors in dogs and cats. Studies on elastography are based on the elasticity and deformation of the evaluated tissue. The information obtained from the different types of elastography can aid in the detection and differentiation of malignant and benign structures. Descriptions of elastography studies in several organs and tissue in veterinary medicine reported that, in general, malignant tumors tend to be more rigid and, therefore, less deformable than benign lesions or in comparison to the healthy parenchyma. Contrast-enhanced ultrasonography is based on the intravenous injection of contrast media constituted by microbubbles. This imaging modality can be performed in nonsedated animals and provides information on the tissue perfusion, allowing the investigation of macro- and micro-circulation. Studies on different organs and tissues were performed in dogs and cats and revealed a tendency of malignant tumors to present faster transit of the contrast media (time to wash-in, peak and wash-out). These advanced techniques can be associated with other imaging modalities, aiding important information to the well-established exams of B-mode and Doppler ultrasonography. They can be used as screening tests, potentially representing an alternative to the invasive sampling methods required for cytological and histopathological analysis.

The thyroid of dogs has not been extensively studied in 2D shear-wave elastography, making it challenging to apply this technique in the diagnosis of thyroid diseases in a non-invasive manner. The aim of this study is to evaluate the thyroid glands of healthy dogs using 2D shear-wave elastography in order to establish qualitative and quantitative parameters of tissue stiffness in dogs in different age groups. A total of 31 dogs of various breeds, sexes, and sizes were evaluated. Animals with clinical signs or ultrasound findings indicative of endocrine disease or thyroid lesions were excluded from the study. The shear-wave velocity data in meters per second (m/s) and color elastograms were evaluated and calculated using QelaXto™ 2D software. A healthy thyroid exhibits a blue-color elastogram, indicative of low stiffness. The reference range for the shear-wave velocity of thyroid tissue assessed by 2D shear-wave elastography can be between 1.6 and 2.0 m/s, with a variation of ±0.889 in adult and senior dogs.

Sixty adrenals of 30 dogs were evaluated, divided into three groups, according to age: Group 1 = healthy youngsters (10 animals) - from one to three years old; Group 2 = healthy adults (10 animals) - four to nine years old; and Group 3 = healthy senile animals (10 animals) - older than ten years old. The experimental design was randomized, with a significance of 5%. There was a significant difference (P=0.017) in length between young and elderly dogs. The thickness of the cranial pole showed a significant difference (P=0.001) between young and adults when compared with the elderly group. The thickness of the caudal pole was not significant for adults when compared to elderly and young people. Between elderly and young, the difference was significant (P=0.024). The mean speeds differed between the groups of young and adult animals regarding the left adrenal and its cranial pole. The hardness pattern and its measurements can vary in healthy dogs of different ages, being more rigid in the cranial pole of the left adrenal in young dogs.

This study aimed to evaluate the applicability of fetal heart rate variability (FHRvar%), umbilical artery resistivity index (RI-UmbArt), and maternal body temperature (Temp, °C) for predicting parturition in bitches. Fifteen bitches (1-6 years old) were included. Gestational age was estimated using fetal biometry (inner chorionic cavity or biparietal diameter), and during the last week of pregnancy the animals were evaluated twice daily until parturition. Data were retrospectively grouped according to the hours before parturition (HBP). The evaluated parameters were FHRvar% (measured over 5-10 minutes using pulsed Doppler abdominal ultrasonography), RI-UmbArt (assessed by triplex Doppler in three fetuses per session), and Temp (rectal thermometry). Data were statistically compared and correlated with HBP. FHRvar% showed a gradual increase (P = 0.010) beginning at 84 HBP, reaching a peak between 24 and 12 HBP, whereas Temp significantly decreased during the last 24 HBP (P < 0.001). Both FHRvar% and Temp were significantly correlated with HBP (P < 0.001); however, these correlations were weak (Pearson’s r = −0.338 and −0.491, respectively). RI-UmbArt showed no significant variation across HBP (P = 0.711). An FHRvar% > 31.5% predicted parturition within 24 hours with a sensitivity of 65% and a specificity of 67%, whereas a Temp < 37.5°C predicted parturition with 69.6% sensitivity and 77.8% specificity. In conclusion, although FHRvar% and maternal body temperature are influenced by the proximity of parturition, they may not be reliable predictors of parturition timing, while RI-UmbArt appears to remain unchanged close to delivery.

Background: Primary pulmonary neoplasia, although considered uncommon in dogs, may have its significance underestimated due to diagnostic challenges. The search for alternatives that provide relevant information for both diagnosis and prognosis is crucial for guiding therapeutic decisions. In this context, the combination of multimodal diagnostic methods and the application of techniques such as elastography and contrast-enhanced ultrasound (CEUS) have shown promising results. These modalities can provide predictive data for malignancy, particularly in patients whose debilitated condition may discourage the use of more invasive diagnostic techniques or those requiring anesthetic preparation. Case: A 12-year-old mixed-breed bitch, weighing 19.5 kg, was attended with a history of respiratory clinical signs persisting for approximately 1 year, with recent worsening. During physical examination, in addition to the primary complaint, the patient presented nodules in the mammary chain, which cytological analysis revealed an active chronic inflammatory process. Due to the main complaint and the characterization of the nodular structures in the mammary chain, thoracic radiography was requested for pulmonary evaluation. Radiographic findings revealed a pulmonary nodule measuring approximately 6.5 cm in diameter in the right middle lung lobe, along with a predominant unstructured broncho-interstitial lung pattern, dilation of the main bronchi, and dorsal displacement of mediastinal structures. To obtain complementary information regarding the pulmonary neoformation, ultrasonographic techniques - including B-mode imaging, elastography, and CEUS - were performed, all of which suggested malignancy. Additionally, computed tomography (CT) was conducted to further detail the radiographic findings and delineate the lesion’s topography and dimensions. The combination of these imaging modalities was fundamental for clinical decision-making and surgical planning. A pulmonary lobectomy was performed to remove the caudal and cranial lobes of the right hemithorax, which were compromised by the tumor and adhesions, along with a tracheobronchial lymphadenectomy (medial and right lymph nodes). Histopathological analysis confirmed malignancy, diagnosing papillary pulmonary adenocarcinoma, with severe bacterial suppurative pneumonia, hemorrhage, and marked focal pulmonary edema in adjacent lung tissue. Additionally, tracheobronchial lymph nodes exhibited hyperplasia associated with reactivity. The patient died 2 weeks after surgery. Discussion: This case report aims to demonstrate the applicability of multimodal imaging diagnostics in the identification of primary pulmonary neoplasms and the benefits of combining contemporary techniques with those traditionally used in clinical practice for the characterization of malignancy-associated factors and therapeutic decision-making. B-mode ultrasound provided information regarding the shape, echogenicity, and echotexture of the neoformation, along with B-lines adjacent to the altered tissue. Elastography revealed increased stiffness of the pulmonary mass, a finding suggestive of malignancy. CEUS provided details about the tumor’s perfusion and contrast enhancement pattern, showing non-homogeneous, centrifugal filling with hypoenhancement in the wash-in, peak, and wash-out phases - features indicative of malignancy. These findings highlight the potential value of these techniques in guiding similar cases and future studies on primary pulmonary neoplasia in dogs, as well as in expanding the routine applicability of CEUS and elastography in veterinary practice. Keywords: pulmonary adenocarcinoma, malignant neoplasm, multimodal imaging, elastography, contrast-enhanced ultrasound, CEUS, dog.