Diagnostic imaging descriptions and prevalence of presumed phrenic lymph nodes in dogs.

The phrenic lymph node (PLN) has been described in bovine, equine, and feline anatomic references but descriptions in canine anatomic references are currently lacking. Authors have observed a well-defined, soft tissue attenuating, contrast-enhancing structure in a location consistent with previous anatomic descriptions of the PLN in dogs that underwent thoracic CT for neoplastic staging. The aims of this two-part, retrospective/prospective, anatomic, prevalence study were (1) to describe the presence of a soft tissue structure close to the thoracic caudal vena cava, defined as the presumed PLN, in a series of dogs that underwent CT as part of the staging for metastatic disease; (2) to confirm the lymphatic origin of the presumed PLN in a dog through postmortem examination; (3) to assess the prevalence of the presumed PLN in a population of dogs that underwent thoracic CT or MRI for different clinical purposes; and (4) to assess the possibility to visualize the presumed PLN with ultrasonography. The lymphatic origin of the presumed PLN was confirmed by postmortem examination in one dog. The presumed PLN was visible in 29 of 777 canine CT examinations (prevalence 3.7%). The presumed PLN was not visible in 9 of 10 prospectively recruited ultrasound cases. Most dogs with visible presumed PLNs were large-medium breeds that were presented for neoplastic staging purposes. Findings indicated that a structure consistent with the previously reported anatomic features of PLN in cattle, horses, and cats may be detected with a low prevalence in canine CT and MRI examinations.

Delayed non-selective contrast-enhanced CT can reveal spontaneous contrast enhancement of the lymphatic system in cats.

The authors incidentally observed that, on delayed postcontrast CT studies, feline patients could show increased attenuation of the lymphatic system. The aim of the present study was to evaluate if the lymphatic system of feline patients undergoing intravenous administration of contrast medium might consistently enhance on delayed postcontrast CT studies. Feline patients that underwent CT examination for variable diagnostic purposes were included in this multicentric observational descriptive study. A 10-min delayed postcontrast whole-body CT series was obtained for all cats enrolled and the following anatomic structures were systematically assessed: mesenteric lymphatic vessels, hepatic lymphatic vessels, cisterna chyli, thoracic duct, and anastomosis of the thoracic duct with the systemic venous system. A total of 47 cats were included in the study. The mesenteric lymphatic vessels showed enhancement in the selected series in 39 of 47 (83%) patients and the hepatic lymphatic vessels in 38 of 47 (81%) patients. The cisterna chyli, thoracic duct, and the point of anastomosis of the thoracic duct with the systemic venous circulation were enhanced in 43 (91%), 39 (83%), and 31 of 47 (66%) cats, respectively. This study confirms the initial observation. The mesenteric and hepatic lymphatic system, the cisterna chyli, the thoracic duct, and its anastomosis with the systemic venous circulation of feline patients undergoing intravenous administration of iodinated contrast medium can show spontaneous contrast enhancement in non-selective 10-min delayed contrast-enhanced CT series.

Multidetector-row CT features and histopathological analysis of pericardial recesses in dogs.

At the level of pericardial reflections and near the great thoracic vessels, pericardial recesses (PRs) are present, where fluid can collect to increase the pericardial reserve volume. To date, these structures have not been described in vivo in veterinary patients. The aims of this observational and descriptive study were to describe the location and appearance of PRs in dogs, as seen with multidetector-row CT (MDCT), and to develop a dedicated imaging technique for their best visualization. Dogs who underwent MDCT examination of the whole body were included in the study and CT data were retrospectively evaluated. Dogs with any thoracic abnormality were excluded. MDCT analysis of the PR's was compared with the pathological features of PRs. PRs were identified as fluid-attenuating (10-30 HU), non-enhancing structures showing varied appearance. Two types of PRs were identified at the level of the transverse sinus of the pericardium and classified on the basis of their anatomic location: the aortic recess and the pulmonic recess. A third pericardial fluid-containing structure was seen in a little number of cases, at the level of the termination of the caudal vena cava into the right atrium. A dorsal, slight oblique multiplanar section through the aortic bulb resulted the best technique for visualization of all the recesses. Anatomo-pathological evaluation confirmed the location and the presence of pocket-like reflections of the pericardium identified with 3D-CT models. Knowledge of the CT appearance of the pericardial recesses is necessary in order to avoid their misinterpretation and subsequent unnecessary invasive investigations.

CT features of primary bone neoplasia of the thoracic wall in dogs.

Primary thoracic wall neoplasia is uncommon in dogs and the prognosis depends on tumor type. The aims of this retrospective, multi-center, observational study were to describe CT features of primary thoracic wall neoplasia in dogs and to test the hypothesis that CT features would differ among tumor types. Dogs with a diagnosis of primary thoracic wall bone neoplasia and thoracic CT study were included. CT findings recorded were as follows: dimensions, location, invasiveness, grade and type of mineral attenuation, periosteal reaction, contrast enhancement, and presence of presumed pulmonary metastases, pleural effusion, and sternal lymphadenopathy. Fifty-eight cases were included (54 ribs and four sternum). Fifty-six were malignant (sarcomas - SARC) and two were benign (chondromas - CHO). Out of the 56 malignant tumors, 41 had histological confirmation of the tumor type: 23 (56%) osteosarcomas (OSA), 10 (24%) chondrosarcomas (CSA), and eight (20%) hemangiosarcomas (HSA). The majority of rib tumors were right-sided (59%) and ventrally located (72%). Malignant masses showed severe invasiveness, mild/moderate contrast enhancement, and different grades of mineral attenuation. Sternal lymphadenopathy was significantly more frequent in dogs with OSA and HSA compared to dogs with CSA (p = 0.004 and p = 0.023). Dogs with HSA showed significantly lower mineral attenuation grades compared to dogs with OSA (p = 0.043). Primary thoracic wall bone neoplasias were more frequently arising from the ribs, with only a few cases of sternal masses. Findings can be used to help prioritize differential diagnoses for CT studies of dogs with thoracic wall neoplasia.

CT Characteristics of the Thymus in Adult Dogs with Non-Thymic Neoplasia Compared to Young Dogs.

The thymus is a lymphatic mediastinal organ that is largely subject to changes with age. In human patients, the CT characteristics of the thymus in children and adults is well described. Furthermore, it is known in human medicine that stress can lead to a reduction in the size of the thymus, followed by a phase of hyperplasia (called the 'rebound effect'). The visualization of thymic tissue in the cranial mediastinum of adult dogs with neoplasia is possible and could be related to a similar effect. In this study, we aimed to describe the CT characteristics of the thymus in adult dogs with neoplasia and to compare the aspect of the thymus in these dogs to juvenile dogs with a presumed normal thymus. A total of 11 adult dogs with neoplasia and 20 juvenile dogs were included. Several CT features of the thymus were evaluated, including the size, shape, and pre- and post-contrast attenuation values. The overall appearance was lobulated in all of the adult dogs and homogeneous in all of the juvenile dogs; it was left-sided in all of the adult dogs, while it was located in the midline in a few of the juvenile dogs (right-sided only in one). The thymus was less attenuating in adult dogs, in some cases with negative minimum pre-contrast attenuation values. In some dogs with neoplasia, the thymus can be detected at CT examination despite their age.

Right auricle aneurysm in dogs can be detected with multidetector-row CT and presents with varying morphology.

Right auricle aneurysm (RAA) has been reported to be a rare congenital or acquired condition in dogs, however published CT characteristics are limited to a small number of cases. The aim of this 13-year, single-center, retrospective, cross-sectional study was to describe the prevalence and appearance of RAA in a larger group of dogs. Reports of 10,886 dogs that underwent thoracic CT examination for various reasons were reviewed. Computed tomographic data of dogs with presumed RAA (based on published imaging characteristics) were retrieved from the archive. Oblique multiplanar reformatted images were used to record RAA site, shape, and dimensions (neck, maximum height and width). Patients' sex, age, and body weight were evaluated for any association with the presence of RAA. Presumed RAA was detected in 23/10,886 dogs having thoracic CT in the selected period of time (prevalence 0.21%). Three RAA phenotypes were described: diffuse saccular dilation in 19 of 23 dogs, focal saccular dilation in three of 23 dogs, and fusiform in one of 23 dogs. The bodyweights of dogs with presumed RAA were significantly lower than those of the remaining 10836 dogs without RAA (median 8 kg [IQR 5; range 37.6] and median 16 kg [IQR 23; range 116.9] respectively; P < 0.003. Female sex was also significantly associated with RAA (P = 0.03). Findings indicated that RAA has a low prevalence in dogs, can be detected with CT, can be present in asymptomatic dogs, and can have varying appearances. In this sample of dogs, female sex and low body weight were significantly associated with RAA.

Sternal lymphadenopathy in dogs with malignancy in different localizations: A CT retrospective study of 60 cases.

Sternal lymph nodes (SLNs) drain a multitude of regions in dogs, including the pectoral and shoulder region, the thoracic wall and mammary glands, the mediastinum, thymus, diaphragm, and the ventral abdominal wall and peritoneal cavity. Neoplastic conditions of these regions can lead to sternal lymphadenopathy. The aim of this study was to assess the most frequent localizations of the primary neoplasia and the most frequent tumor types in dogs with sternal lymphadenopathy. Computed tomographic (CT) characteristics of SLNs in dogs with confirmed neoplasia were also described. For this single-center retrospective descriptive study, dogs with sternal lymphadenopathy and cytological or histological diagnosis of neoplasia were included. Sixty dogs fulfilled the inclusion criteria: 30 (50%) with thoracic neoplasia, 19 (32%) with abdominal neoplasia, 6 (10%) with neoplasia of the front limbs and 5 (8%) with generalized neoplasia. Based on the cytological/histological diagnosis of the primary neoplasia, 31/60 (52%) dogs presented with a sarcoma, 15/60 (25%) with carcinoma, and 14/60 (23%) with round cell tumor. The presence of heterogeneous contrast enhancement was more frequent in dogs with sarcoma, while the concomitant presence of other abnormal lymph nodes was more frequent in dogs with round cell neoplasia. Tumors of different types and in different location can result in sternal lymphadenopathy in dogs. The most frequent in this study were thoracic and abdominal neoplasia, followed by neoplasia of the shoulder region. Sarcoma was the most common tumor type detected in this study, and the main CT characteristic of the SLNs in case of sarcoma was heterogeneous contrast enhancement.

Multi-phase MULTIDETECTOR-row computed tomographic features and laboratory findings in dogs with gallbladder rupture.

Gallbladder rupture is a life-treating condition in dogs. In human medicine, multidetector-row computed tomography (MDCT) is considered the best modality for the diagnosis of gallbladder rupture. The aims of the study were to describe MDCT features of gallbladder rupture in dogs and to determine the CT findings and laboratory data that differ between dogs with ruptured biliary tree and dogs with biliary disease with no rupture. For this single-center, cross-sectional study were considered for inclusion dogs presented from May 2010 to September 2020, with surgical diagnosis of gallbladder rupture or integrity, who underwent MDCT examination and with CBC and biochemistry results available for review. Forty-seven dogs with different diseases of the biliary tract were included. Seventeen dogs with confirmed gallbladder rupture and 30 dogs with intact gallbladder were included. Multiple MDCT findings showed statistical significance in distinguish dogs with gallbladder rupture: irregular contours of the gallbladder (p < 0.0001), discontinuation of the gallbladder wall (p = 0.0005), adhesions with adjacent organs (p = 0.005), heterogeneous enhancement of the gallbladder wall (p = 0.01), pericholecystic effusion (p = 0.001) and pericholecystic peritonitis (p = 0.001). The presence of three or more of these findings was highly indicative for gallbladder rupture (AUC = 0.921). In this study, MDCT proved to be useful in differentiating dogs with gallbladder rupture from dogs with biliary disease without rupture.

Multidetector-Row CT Findings in Dogs with Different Primary Parathyroid Gland Diseases.

Primary hyperparathyroidism in dogs is a possibly life-threatening condition, characterized by the excess of parathyroid hormone (PTH) secretion, which leads to an increase in serum ionized calcium level. The utility of computed tomography (CT) in the detection and characterization of parathyroid diseases in dogs has not been assessed to date. Therefore, the aim of this study was to describe the use of multidetector-row CT (MDCT) for the diagnosis of parathyroid disease in dogs. For this descriptive, single-center study, the database of the San Marco Veterinary Clinic was searched for dogs having a suspicion of parathyroid disease who underwent contrast-enhanced MDCT in the period from 2005 to 2021. Dogs with histopathology of the affected parathyroid gland were subsequently considered for inclusion. A total of 22 parathyroid glands were included: 12 adenomas, 8 adenocarcinomas, and two glands with hyperplasia. Several CT features were evaluated, including parathyroid gland affected, lateralization, shape, size, attenuation, and contrast-enhancement. Although the overlap between the appearance of different diseases exists, contrast-enhanced CT was a useful method for the diagnosis of parathyroid disease in dogs.

Use of Contrast-Enhanced Ultrasonography and Shear-Wave Elastography in the Diagnosis of Granulomatous Colitis in a French Bulldog.

An 11-month-old male intact French Bulldog was referred for chronic intermittent diarrhea lasting three months. Ultrasonographic (US) examination revealed severe thickening of the wall of the colon and caecum; contrast-enhanced US (CEUS) and elastography showed increased, heterogeneous vascularization and non-uniform stiffness of the colonic wall. The mucosa was thickened, fragile, and ulcerated as revealed by endoscopy, and histological examination confirmed the suspicion of granulomatous colitis.

Multiphase multidetector-row computed tomographic and ultrasonographic findings in dogs with spontaneous liver lobe torsion.

Liver lobe torsion (LLT) is an uncommon condition of unknown origin in dogs. Several reports describe the clinical features and outcome, but only few of them include the imaging characteristics of this disease. The aim of this descriptive case series was to describe the ultrasonographic (US) and multidetector-row computed tomographic (MDCT) features of LLT in a group of dogs. Five dogs were included in this single-center descriptive study, having both US, CT and surgical and histological confirmation of LLT available for review. Different US appearances have been found, both hypoechoic and hyperechoic liver lobes and heterogeneous mass-like lesions, with fluid and gas content. At three-phase MDCT examination, LLT appeared as fluid- and gas-filled lesions (consistent with abscess transformation), or as hypoattenuating hypovascular lobes. Two different vascular signs were also described: whirl sign or vascular interruption were seen in all cases, allowing a correct pre-surgical diagnosis in all the cases presented. Multiphase MDCT was a helpful imaging method for the correct pre-surgical diagnosis of LLT in dogs, and its use in the suspected cases is therefore advisable.

Multiphase multidetector-row CT reveals different patterns of hepatic portal venous gas and pneumobilia.

Hepatic portal venous gas and pneumobilia (PB) are uncommon findings, indicating the accumulation of gas in the portal vein and its branches and in the biliary tree, respectively. Aims of this retrospective, descriptive study were to describe the computed tomographic (CT) features and visualization techniques of hepatic portal venous gas (HPVG) and PB in a group of small animal veterinary patients. The CT data of patients with HPVG and PB were retrospectively reviewed. Thin-section multiplanar reformatting and minimum intensity projection (MinIP) views were used to assess the acquired volume dataset. The CT features recorded were as follows: amount, aspect, distribution, and localization of the gas in the liver. Five patients were included (four dogs and one cat), two presenting HPVG and three with PB. Gas in HPVG presented a peripheral location, whereas in PB was characterized by a central location. The aspect of the gas was tubular in case of HPVG and mixed tubular and rounded in PB. An analogous number of animals between the two groups showed comparable amount (mild, moderate, and severe) and distribution (diffuse and focal). Thin-section CT can detect the presence of gas in the liver, and a combination of two-dimensional and thin-slab MinIP can differentiate between HPVG and PB in dogs and cats. The distinctive features are peripheral versus central location and tubular versus rounded aspect of the gas.

Use of Contrast-Enhanced Ultrasonography for the Characterization of Tumor Thrombi in Seven Dogs.

Tumors of adrenal and thyroid glands have been associated with vascular invasions-so-called tumor thrombi, both in humans and dogs. The detection and characterization of venous thrombi is an important diagnostic step in patients with primary tumors for both surgical planning and prognosis. The aim of this study was to describe the use of contrast-enhanced ultrasonography (CEUS) for the characterization of tumor thrombi. Dogs with tumor thrombus who underwent bi-dimensional ultrasound (B-mode US) and CEUS were included. Seven dogs were enrolled in this retrospective case series. On B-mode US, all thrombi were visualized, and vascular distension and thrombus-tumor continuity were seen in three and two cases, respectively. On color Doppler examination, all thrombi were identified, seemed non-occlusive and only two presented vascularity. On CEUS, arterial-phase enhancement and washout in the venous phase were observed in all cases. Non-enhancing areas were identified in the tumor thrombi most likely representing non-vascularized tissue that could potentially be embolized in the lungs after fragmentation of the tumor thrombi. On the basis of these preliminary study, CEUS appeared to be useful for the characterization of malignant intravascular invasion.

The ultrasonographic medullary "rim sign" versus medullary "band sign" in cats and their association with renal disease.

BACKGROUND: Medullary rim sign (MRS) refers to a hyperechoic line in the renal medulla, reported on ultrasound examination (US) in both dogs and cats with and without kidney disease (KD). OBJECTIVE: To describe the different aspects of MRS in cats and to assess its association with KD. ANIMALS: Cats that underwent US examination, with MRS (study group) with and without KD and without MRS with and without KD (control groups). METHODS: Retrospective case-control study: cats with MRS, with or without KD (rim sign groups) and cats without MRS, with or without KD (control groups). Ultrasonographic images were blindly reviewed with attention given to the thickness and margins of the MRS recorded. RESULTS: Eighty-four cats with MRS were included and 60 cats recruited for each control group. The MRS had 2 distinct aspects: a thin hyperechoic line with well-defined margins (MRS-line) in 50/84 cats (59%) and a thick hyperechoic band with ill-defined margins (MRS-band) in 34/84 cats (41%). Twenty of 50 (40%) cats with MRS-line and 25/34 (74%) of cats with MRS-band had KD. The frequency of MRS-line was higher in cats without KD, whereas the presence of MRS-band was more frequent in cats with KD (P = .003). CONCLUSIONS AND CLINICAL IMPORTANCE: A thick hyperechoic ill-defined band (for which the term medullary band sign is proposed) was more frequently associated with KD, whereas a thin hyperechoic well-defined line (true MRS) may be seen in cats with or without KD.

Splenic extramedullary hematopoiesis in dogs is frequently detected on multiphase multidetector-row CT as hypervascular nodules.

Extramedullary hematopoiesis (EMH) is the formation and development of blood cells outside the bone marrow, and in dogs it frequently occurs in the spleen. Although splenic EMH is a relatively common condition, data regarding its appearance in veterinary medicine are lacking. Our aim was to describe different multidetector computed tomographic (MDCT) features of splenic EMH in dogs. In this descriptive retrospective study, dogs with cytological diagnosis of splenic EMH and three-phase MDCT study of the abdomen were included. Multi-detector CT findings recorded were splenomegaly, appearance of the parenchyma, and mean attenuation of the spleen and lesions. Out of 89 dogs included, 55 (62%) presented multifocal nodular aspect, 14 (16%) mass, 12 (13%) diffuse heterogeneous parenchyma, and eight (9%) normal spleen. Most lesions were hyperattenuating to the parenchyma in the arterial (57/89, 64%) and portal (59/89, 66%) phases; whereas in the interstitial phase only 40 of 89 (45%) were hyperattenuating. The mean attenuations of the lesions were higher compared to the values of the adjacent spleen, and the difference of the mean attenuation between the hyperattenuating lesions and the parenchyma was significantly higher in arterial and portal phases than in interstitial phase (P < .0001). The most frequent MDCT aspect of splenic extramedullary hematopoiesis consists of multiple nodules hyperattenuating to the normal spleen, best visualized in the arterial and portal phases.

Relationship between the stage of osteoarthritis before and six months after tibial tuberosity advancement procedure in dogs.

The present retrospective study evaluated the progression of osteoarthritis in stifle joints based on the radiographic grade of osteoarthritis (OA) scored in dogs with cranial cruciate ligament rupture. The aim of the study was to search for a correlation between the stage of radiographic osteoarthritis prior to surgery and the osteoarthritis progression occurring after the tibial tuberosity advancement (TTA) procedure. It was hypothesized that the procedure carried out in dogs in the early stages of OA could reduce the OA changes. A total of 190 X-ray images obtained from the medical records of 38 dogs were evaluated. The radiographic signs of osteoarthritis of 38 stifle joints were scored from 0 to 3 in 10 specific anatomic locations. The radiographs were divided into 4 groups based on the global scores: A) no-OA, B) mild-OA, C) moderate-OA, D) severe-OA; they were assessed prior to surgery, and 1, 2, 3 and 6 months post-operatively (T0, T1, T2, T3 and T6). There were no differences in osteoarthritis progression in Groups A and C at any time. Osteoarthritis changes from T0 to T6 were statistically significant in Group B. The OA changes in the anatomic locations were investigated. The most common anatomic sites for OA changes were the patella apex, the proximal and distal trochlear ridges, and the caudal aspect of the tibial plateau assessed before surgery. After surgery, the score increased in the first three locations in 10, 9 and 11 joints, respectively; instead, the progression of osteoarthritis in the caudal aspect of the tibial plateau occurred in 23 out of 38 stifle joints. The results indicated that the TTA procedure could be effective in slowing down the OA progression when carried out in the absence of or in the early stages of disease. Therefore, an early intervention may be suggested in clinical practice to obtain minimal or no progression 6 months postoperatively.

Diagnostic accuracy of the vertebral heart score and other radiographic indices in the detection of cardiac enlargement in cats with different cardiac disorders.

A retrospective search was conducted to evaluate the diagnostic accuracy of the vertebral heart score (VHS) and other related radiographic indices in the detection of cardiac enlargement associated with different cardiac disorders in the cat. One hundred and five cats with a complete echocardiographic examination and radiographic examination of the thorax with at least two orthogonal views were enrolled. Eighty-three cats had different cardiac disorders, 72 with left-sided cardiac disorders (LSCD) and 11 with right-sided cardiac disorders; 22 cats were free of cardiovascular abnormalities. Measurements of VHS and cardiac long and short axes on lateral (L) and dorsoventral or ventrodorsal radiographs were obtained. Receiver operating characteristic curves were calculated to evaluate the diagnostic accuracy of each radiographic index in differentiating between cats with cardiac disorders or cats with LSCD and cats without cardiac abnormalities and, among cats with LSCD, between those with no or mild left atrial enlargement (LAE) or those with moderate-to-severe LAE and healthy cats. The L-VHS at the cut-off of 7.9 had high diagnostic accuracy in distinguishing cats with LSCD and moderate-to-severe LAE from healthy cats, but all the other radiographic indices were moderately accurate in distinguishing between cats with overall cardiac disorders or LSCD, either with no or mild LAE and moderate-to-severe LAE, and healthy cats. The considered radiographic indices were also moderately accurate in predicting different degrees of LAE in cats with LSCD. Radiographic indices are reasonably specific, but less sensitive predictors of cardiac enlargement in cats with heart disorders.