CT features of rounded atelectasis in chronic inflammatory pleural effusions in cats and dogs.

Rounded atelectasis is well described in human medicine as focal lung deformation and collapse secondary to inflammatory pleural effusions and pleuritis. Specific CT features (round to ovoid soft tissue pulmonary attenuations, creation of an acute angle with the adjoining visceral pleura, and the presence of perinodular comet tail signs) support the diagnosis of rounded atelectasis in humans so that further diagnostic workup is not necessary in defining the nodules. In this retrospective case series, we described the CT characteristics of rounded atelectasis in eight cats and three dogs diagnosed with restrictive pleuritis secondary to either a chylothorax or pyothorax. Thirty-six soft tissue attenuating pulmonary nodular lesions were identified on CT. Comet tail signs, consisting of bundles of bronchi and vessels coalescing into the pulmonary nodules, were associated with 92% of the nodules (33/36), and 92% of the nodules abutted and created an acute angle with the pleura (33/36). Other prevalent features included location in gravity-dependent regions of the lung lobes (33/36, 92%), blurred hilar margins with sharper pleural margins of the nodules (33/36, 92%), presence of air bronchograms (30/36, 83%), homogeneous contrast-enhancement (23/36, 64%), and volume loss of the affected lung lobe (22/36, 61%). Pulmonary malignant neoplasms were not found cytologically (6/11 patients) or histologically (5/11 patients). To avoid a misdiagnosis of neoplasia, veterinary radiologists should be aware of the CT features of rounded atelectasis and consider it as a differential for pulmonary nodular lesions in patients with concurrent inflammatory pleural effusion and pleuritis.

Disseminated coelomic xanthogranulomatosis in eclectus parrots (Eclectus roratus) and budgerigars (Melopsittacus undulatus).

Xanthogranulomatosis is an inflammatory lesion characterized by lipid-containing macrophages, extracellular lipid, hemorrhage, and necrosis. We describe disseminated intracoelomic xanthogranulomatosis in 5 eclectus parrots (Eclectus roratus) and 2 budgerigars (Melopsittacus undulatus). Postmortem, clinicopathologic, and historical case material was reviewed. Ages ranged from 3 to 24 years; there were 5 males and 2 females. Table food was included in the diet of 3/5 cases, and animal products were included in 2/3 cases. Common clinicopathologic abnormalities included leukocytosis (4/5 cases) and elevated concentrations of bile acids (3/4 cases) and cholesterol within 6 months prior to death (2/4 cases). At postmortem examination, all 7 birds had grossly visible, irregular, soft, tan to yellow, amorphous plaques distributed on the surfaces of the viscera and body wall. Histologic evaluation and oil red O stain revealed xanthogranulomatous inflammation with phagocytized and extracellular lipid, necrosis, cholesterol clefts, fibrosis, and mineralization. Infectious agents were not identified with special stains in all cases. Concurrent hepatobiliary disease was present in 6/7 cases, and 6/7 had lipid accumulation within the parenchyma of various visceral organs. Five cases had atherosclerosis of great vessels. We describe a unique form of disseminated coelomic xanthogranulomatosis in 2 psittacine species. This condition should be recognized as a differential diagnosis in cases of disseminated coelomic mass formation and coelomic distension in psittacine birds, particularly in eclectus parrots and budgerigars.

Radiographic features of subungual keratoacanthomas in dogs.

Subungual keratoacanthoma (SK) is a digital neoplasm that has rarely been reported in dogs and carries an excellent prognosis following surgical removal. Radiographic features of canine SK have only been briefly discussed in two prior case reports. Both articles described extensive distal phalangeal osteolysis, a feature more commonly associated with malignant digital neoplasms (e.g., subungual squamous cell carcinoma (SCC) or melanoma). This retrospective case series aimed to further characterize radiographic findings of histologically confirmed canine SK. Seven dogs met the inclusion criteria, with a total of seven affected digits. All seven digits (100%) had osteolysis of the distal phalanx's ungual process and crest, as well as regional soft tissue swelling. Osteolysis of the ungual process was severe in all cases, with complete destruction in six of seven digits (86%). Partial ungual crest geographic and expansile osteolysis was noted in four of seven digits (57%), while two digits (28%) had complete ungual crest destruction. Seven of seven digits (100%) had a radiographically thickened claw, and two of seven digits (28%) had associated lysis of the distal aspect of the middle phalanx. Based on these findings, an osteolytic subungual mass should not be considered pathognomonic for malignant neoplasia. Observing the imaging features previously described should prompt veterinarians to consider SK as a differential diagnosis.

Secondary extracranial paranasal sinus meningioma in a dog.

A 13-year-old Maltese dog was presented for inspiratory stertor. A computed tomography evaluation was performed and revealed an osteoproductive lesion primarily centered over the frontal bone with infiltration of the adjacent maxillary and nasal bones, focal intracranial invasion, and an associated broad-based, contrastenhancing, extra-axial lesion along the longitudinal cerebral fissure. Rhinoscopic and incisional biopsies of the paranasal mass were obtained, and a meningioma was diagnosed histologically. Based on the imaging features and histopathology results, an extracranial paranasal sinus meningioma was diagnosed in this dog. To the authors' knowledge, this is the first case report describing the computed tomographic findings associated with a secondary extracranial paranasal sinus meningioma in a dog. Key clinical message: Meningiomas in dogs can be present outside of the brain case and should be considered a differential for tumors of the paranasal sinuses.

Méningiome extra-crânien secondaire du sinus paranasal chez un chien. Un chien maltais de 13 ans a été présenté pour un stertor inspiratoire. Une évaluation par tomodensitométrie a été réalisée et a révélé une lésion ostéoproductive principalement centrée sur l'os frontal avec une infiltration des os maxillaires et nasaux adjacents, une invasion intracrânienne focale et une lésion extra-axiale à large base associée, augmentant le contraste, le long de la fissure cérébrale longitudinale. Des biopsies rhinoscopiques et incisionnelles de la masse paranasale ont été obtenues et un méningiome a été diagnostiqué histologiquement. Sur la base des caractéristiques d'imagerie et des résultats de l'histopathologie, un méningiome extra-crânien du sinus paranasal a été diagnostiqué chez ce chien. À la connaissance des auteurs, il s'agit du premier rapport de cas décrivant les résultats tomodensitométriques associés à un méningiome extra-crânien secondaire du sinus paranasal chez un chien.Message clinique clé :Les méningiomes chez le chien peuvent être présents en dehors du cerveau et doivent être considérés comme un différentiel pour les tumeurs des sinus paranasaux.(Traduit par Dr Serge Messier).

Computed tomography with Hounsfield unit assessment is useful in the diagnosis of liver lobe torsion in pet rabbits (Oryctolagus cuniculus).

Clinical signs of liver lobe torsion in rabbits are often nonspecific and mimic those that are also generally detected with gastrointestinal stasis. Nonspecific clinical signs may result in pursuit of full-body imaging such as computed tomography (CT). The aim of this multicenter, retrospective, case series study was to describe CT findings of liver lobe torsion in a group of rabbits. Computed tomography studies of six rabbits with confirmed liver lobe torsion by surgery or necropsy were evaluated. The caudate liver lobe was affected in six out of six rabbits and was enlarged, rounded, hypoattenuating, heterogeneous, and minimally to noncontrast enhancing, with scant regional peritoneal effusion. Precontrast, mean Hounsfield units (HU) of the torsed liver lobe (39.3 HU [range, 24.4-48.1 HU]) were lower than mean HU of normal liver (55.1 HU [range, 49.6-60.8 HU]), with a mean torsed:normal HU ratio of 0.71 (range, 0.49-0.91). Postcontrast, mean HU of the torsed liver lobe (38.4 HU [range, 19.7-48.9 HU]) were also lower than mean HU of normal liver (108.4 HU [range, 84.5-142.0 HU]), with a lower postcontrast mean torsed:normal HU ratio of 0.35 (range, 0.14-0.48) compared to precontrast. Mean HU of torsed liver lobes had little difference pre- and postcontrast (postcontrast HU 1.0 times the average precontrast HU [range, 0.81-1.1]), and contrast enhancement of the torsed liver lobes was on average 50% lower than in normal liver. Liver lobe torsion should be considered in rabbits with an enlarged, hypoattenuating, heterogeneous, minimally to noncontrast enhancing liver lobe, particularly the caudate lobe, and scant regional peritoneal effusion.

COMPUTED TOMOGRAPHY OF CUTANEOUS MYIASIS IN AN ORNATE BOX TURTLE (TERRAPENE ORNATA ORNATA).

A juvenile intact female ornate box turtle (Terrapene ornata ornata) was referred for evaluation of right-sided appendicular swelling that was nonresponsive to antimicrobial therapy. Computed tomography (CT) revealed severe soft tissue swelling of the limbs and neck, with multiple associated tortuous gas-filled sinus tracts extending from the cutaneous surface, which contained oblong soft tissue attenuating structures. These CT findings were most consistent with migrating dipterous larvae. Surgical exploration was performed and six sarcophagid larvae (Superfamily Oestroidea) were extracted. To our knowledge, this is the first case report in veterinary medicine providing antemortem CT imaging features of cutaneous myiasis in a reptile.

Mensuration of the rabbit pituitary gland from computed tomography.

The aim of this retrospective reference interval observational study was to determine the mensuration of the pituitary gland (hypophysis cerebri) by analyzing CT studies in rabbits without clinical evidence of pituitary disease or central neurologic signs. Though diseases of the rabbit pituitary gland are uncommon, the pituitary gland is essential in regulation of the rabbit's endocrine system, as in other species. Currently, there are minimal published studies that detail the rabbit head anatomy on cross-sectional imaging, and even less specifically examining the pituitary gland. The pituitary gland was measured by one observer at a single time point from transverse and reconstructed sagittal CT images in a soft-tissue algorithm in 62 rabbits for a total of 66 rabbit head CT studies. The rabbits ranged from 0.84 to 14 years in age (mean ± SD: 5.46 ± 3.05 years) and 0.92 to 4.95 kg in weight (2.21 ± 0.83 kg). Linear pituitary measurements were performed using electronic calipers. The mean ± SD pituitary height was 4.22 ± 0.57 mm, width was 4.48 ± 0.71 mm, and length was 6.02 ± 0.70 mm. The pituitary gland height-to-brain area ratio was 1.10 ± 0.16 mm-1 , which is much higher than the values reported in normal dogs and cats. The age, weight, and sex of the rabbits were not found to have a significant impact on pituitary gland mensuration. These measurements could be useful as a reference range for future rabbit head CT studies and to rule out pituitary enlargement or disease when evaluating rabbit pituitary glands.

Radiographic features of suspected suture-associated cystic calculi in dogs.

This retrospective case series describes the radiographic features of suspected suture-associated cystic calculi in six dogs with a history of at least one or multiple prior cystotomies. One of the dogs presented twice. Suspected suture-associated cystic calculi were multifocal, short, predominantly linear mineral opacities localized in the center of the urinary bladder on abdominal radiographs. One patient (n = 1) presented with multifocal round, pin point, and linear radiopaque calculi. The calculi were all calcium oxalate in composition. On gross examination, the calculi had a hollow center. Six cystotomies used monofilament absorbable suture material (polydioxanone [n = 4] or poliglecaprone 25 [n = 1]) in prior cystotomies. Suture material in two of the cases was unknown. Suspected suture-associated cystic calculi are a rare occurrence in veterinary medicine but should be considered in dogs that have a history of prior cystotomy, hollow core on gross analysis, and radiographic evidence of mineral opaque, predominantly linear, cystic calculi.

Imaging features of disseminated xanthogranulomatous inflammation in eclectus parrots (Eclectus roratus).

Xanthogranulomatous disease is a rare condition, which can be caused by infection, inflammation, hemorrhage, immunologic disease, or inherited lysosomal disorders. It is characterized by non-intracellular lipid and cholesterol deposits among an inflammatory infiltrate of vacuolated macrophages and giant cells. The diagnosis of xanthogranulomatous disease is challenging, with nonspecific imaging findings often misinterpreted as aggressive neoplastic processes in humans. In this retrospective case series study, we describe the diagnostic imaging characteristics of a disseminated xanthogranulomatous condition identified in five eclectus parrots (Eclectus roratus). Decreased serosal detail and celomic distension were present in all three birds radiographed, with multifocal variably sized celomic mineralization (3/3 birds), and extracelomic mineralized masses (1/3 birds). Celomic effusion with foci of celomic mineralization and hepatomegaly were identified in all birds (3/3) imaged with ultrasound. Finally, a mineralized mural ventricular mass was present in one of three patients imaged with CT, multifocal celomic mineralization with moderate to severe celomic effusion in two of three patients, diffuse severe proventricular and intestinal dilation in all three patients, and atherosclerosis of the major arterial trunks in all three patients. Veterinary radiologists should be aware of this inflammatory condition in birds, especially in eclectus parrots, and should be able to recognize the imaging features of xanthogranulomatous inflammation.

STANDING COMPUTED TOMOGRAPHY IN NONANESTHETIZED LITTLE PENGUINS (EUDYPTULA MINOR) TO ASSESS RESPIRATORY SYSTEM ANATOMY AND MONITOR DISEASE.

Multidetector computed tomography (MDCT) scans were performed in clinically healthy, nonanesthetized, standing little penguins (Eudyptula minor) to determine reference ranges for air-sac and lung volumes, as well as lung density. Five of 15 clinically healthy birds were diagnosed with pulmonary granulomas on initial MDCT scans. Granulomas were not readily apparent on radiographs, even in cases where the entire normal pulmonary parenchymal architecture was effaced on the MDCT scan. Serial MDCT scans after antifungal and antimycobacterial therapies demonstrated a response to treatment. MDCT scanning in nonanesthetized little penguins proved to be a well-tolerated, non-invasive imaging modality for respiratory diseases that are otherwise difficult to diagnose, including aspergillosis and mycobacteriosis.

OFF-SITE SMARTPHONE VS. STANDARD WORKSTATION IN THE RADIOGRAPHIC DIAGNOSIS OF SMALL INTESTINAL MECHANICAL OBSTRUCTION IN DOGS AND CATS.

Off-site consultations by board-certified veterinary radiologists benefit residents and emergency clinicians by providing immediate feedback and potentially improving patient outcome. Smartphone devices and compressed images transmitted by email or text greatly facilitate availability of these off-site consultations. Criticism of a smartphone interface for off-site consultation is mostly directed at image degradation relative to the standard radiographic viewing room and monitors. The purpose of this retrospective, cross-sectional, methods comparison study was to compare the accuracy of abdominal radiographs in two imaging interfaces (Joint Photographic Experts Group, off-site, smartphone vs. Digital Imaging and Communications in Medicine, on-site, standard workstation) for the diagnosis of small intestinal mechanical obstruction in vomiting dogs and cats. Two board-certified radiologists graded randomized abdominal radiographs using a five-point Likert scale for the presence of mechanical obstruction in 100 dogs or cats presenting for vomiting. The area under the receiver operator characteristic curves for both imaging interfaces was high. The accuracy of the smartphone and traditional workstation was not statistically significantly different for either reviewer (P = 0.384 and P = 0.536). Correlation coefficients were 0.821 and 0.705 for each reviewer when the same radiographic study was viewed in different formats. Accuracy differences between radiologists were potentially related to years of experience. We conclude that off-site expert consultation with a smartphone provides an acceptable interface for accurate diagnosis of small intestinal mechanical obstruction in dogs and cat.

EX VIVO CORRELATION OF ULTRASONOGRAPHIC SMALL INTESTINAL WALL LAYERING WITH HISTOLOGY IN DOGS.

Canine ultrasonographic intestinal layers have been reported to correlate with histological layering. However, discrepancies have been reported in people, and additional layers visualized. The aim of this method comparison study was to describe ex vivo canine small intestinal layering and correlate it with histology. Small intestinal samples of 12 adult dogs euthanized for reasons unrelated to gastrointestinal disease were resected immediately following euthanasia, pinned on a Petri dish, and transverse ultrasonographic images acquired in a water bath, using a high-frequency linear transducer. Transverse histological sections were obtained at the same level. Measurements of the intestinal layers were performed on the ultrasonographic and histological images. No significant statistical differences were noted between the ultrasonographic and histological measurements and strong to very strong (r > 0.7) positive correlation was observed for all layers, except for the serosa, which had a low moderate positive correlation (r = 0.479). In addition to the five established layers, a dual mucosal echogenicity was consistently observed, with seven samples presenting an additional inner mucosal severe hyperechogenicity. Histologically, this dual echogenicity was attributed to the intestinal villi (mildly echogenic) and lamina propria (hypoechoic). The additional inner mucosal severe hyperechogenicity observed in seven samples was attributed to mild-to-moderate lacteal dilation histologically. In 4/12 ileal samples, an additional hyperechoic mucosal line was also observed parallel to the submucosa, corresponding histologically to prominent Peyer's patches. Finally, a hyperechoic line was observed within the muscularis of all samples, corresponding histologically to the interface between the muscularis longitudinal and circular layers.

Short colon syndrome in cats.

BACKGROUND: Shortening of the colon has been described in cats, but its imaging and clinicopathological features remain poorly understood. OBJECTIVES: Description of the signalment, clinical presentation, imaging, endoscopic and histological features of short colon syndrome in cats. ANIMALS: Ninety-three cats diagnosed with short colon. METHODS: Multi-institutional, descriptive, retrospective case series study. Medical records were searched for a diagnosis of short colon on abdominal ultrasonography, computed tomography, endoscopy, autopsy, or a combination of these modalities. RESULTS: The median age of included cats was 12 years at the time of diagnosis. Diarrhea was the most common clinical sign (60/92; 65%), followed by vomiting (36/92; 39%), weight loss (36/92; 39%), and inappetence (24/92; 26%). Thirteen percent of cats (12/92) had no signs of gastrointestinal disease at the time of diagnosis. In addition to a shortened colonic length, 79% (66/84) of cats had concomitant colonic thickening on ultrasonographic examination. On colonoscopy, mucosal ulcerations of the colonic wall were seen in 39% (9/23) of cats. Histopathologically, all cats but 1 (diagnosed simultaneously with colonic small cell lymphoma) had lymphoplasmacytic colitis, and when small intestinal biopsies were performed, concurrent lymphoplasmacytic enteritis or small cell lymphoma of the small intestine. CONCLUSIONS AND CLINICAL IMPORTANCE: Lymphoplasmacytic colitis is seen commonly in cats with short colon, suggesting a potential link between these entities.

Theranostic GPA33-Pretargeted Radioimmunotherapy of Human Colorectal Carcinoma with a Bivalent 177Lu-Labeled Radiohapten.

Radiolabeled small-molecule DOTA-haptens can be combined with antitumor/anti-DOTA bispecific antibodies (BsAbs) for pretargeted radioimmunotherapy (PRIT). For optimized delivery of the theranostic γ- and ß-emitting isotope 177Lu with DOTA-based PRIT (DOTA-PRIT), bivalent Gemini (DOTA-Bn-thiourea-PEG4-thiourea-Bn-DOTA, aka (3,6,9,12-tetraoxatetradecane-1,14-diyl)bis(DOTA-benzyl thiourea)) was developed. Methods: Gemini was synthesized by linking 2 S-2-(4-isothiocyanatobenzyl)-DOTA molecules together via a 1,14-diamino-PEG4 linker. [177Lu]Lu-Gemini was prepared with no-carrier-added 177LuCl3 to a molar-specific activity of 123 GBq/µmol and radiochemical purity of more than 99%. The specificity of BsAb-177Lu-Gemini was verified in vitro. Subsequently, we evaluated biodistribution and whole-body clearance for [177Lu]Lu-Gemini and, for comparison, our gold-standard monovalent [177Lu]Lu-S-2-(4-aminobenzyl)-DOTA ([177Lu]Lu-DOTA-Bn) in naïve (tumor-free) athymic nude mice. For our proof-of-concept system, a 3-step pretargeting approach was performed with an established DOTA-PRIT regimen (anti-GPA33/anti-DOTA IgG-scFv BsAb, a clearing agent, and [177Lu]Lu-Gemini) in mouse models. Results: Initial in vivo studies showed that [177Lu]Lu-Gemini behaved similarly to [177Lu]Lu-DOTA-Bn, with almost identical blood and whole-body clearance kinetics, as well as biodistribution and mouse kidney dosimetry. Pretargeting [177Lu]Lu-Gemini to GPA33-expressing SW1222 human colorectal xenografts was highly effective, leading to absorbed doses of [177Lu]Lu-Gemini for blood, tumor, liver, spleen, and kidneys of 3.99, 455, 6.93, 5.36, and 14.0 cGy/MBq, respectively. Tumor-to-normal tissue absorbed-dose ratios (i.e., therapeutic indices [TIs]) for the blood and kidneys were 114 and 33, respectively. In addition, we demonstrate that the use of bivalent [177Lu]Lu-Gemini in DOTA-PRIT leads to improved TIs and augmented [177Lu]Lu-Gemini tumor uptake and retention in comparison to monovalent [177Lu]Lu-DOTA-Bn. Finally, we established efficacy in SW1222 tumor-bearing mice, demonstrating that a single injection of anti-GPA33 DOTA-PRIT with 44 MBq (1.2 mCi) of [177Lu]Lu-Gemini (estimated tumor-absorbed dose, 200 Gy) induced complete responses in 5 of 5 animals and a histologic cure in 2 of 5 (40%) animals. Moreover, a significant increase in survival compared with nontreated controls was noted (maximum tolerated dose not reached). Conclusion: We have developed a bivalent DOTA-radiohapten, [177Lu]Lu-Gemini, that showed improved radiopharmacology for DOTA-PRIT application. The use of bivalent [177Lu]Lu-Gemini in DOTA-PRIT, as opposed to monovalent [177Lu]Lu-DOTA-Bn, allows curative treatments with considerably less administered 177Lu activity while still achieving high TIs for both the blood (>100) and the kidneys (>30).

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Disseminated pancreatic adenocarcinoma in an eclectus parrot (Eclectus roratus).

CASE DESCRIPTION: A 15-year-old 0.412-kg (0.906-lb) sexually intact male eclectus parrot (Eclectus roratus) was evaluated because its owners found it lethargic and dyspneic at the bottom of its cage. CLINICAL FINDINGS: The parrot was thin and had generalized muscle wasting, diffuse feather loss, pale mucous membranes, and melena. The coelomic cavity was distended and soft on palpation, with coelomic effusion suspected. Results of a CBC indicated leukocytosis with left shift heterophilia, including toxic heterophils, lymphopenia, and anemia. Plasma biochemical analyses revealed severe hyperamylasemia. TREATMENT AND OUTCOME: Radiography revealed no evidence of a metallic foreign body but severe loss of coelomic detail, suggestive of a coelomic mass, coelomic effusion with coelomitis, or both. Ultrasonography and CT revealed severe accumulation of coelomic fluid; a large, heterogeneous, irregularly marginated, and moderately vascularized mass in the caudal aspect of the coelomic cavity; and multiple hepatic, coelomic, and pulmonary nodules. On the basis of a poor prognosis, the parrot was euthanized. Necropsy results confirmed exocrine pancreatic adenocarcinoma, with disseminated metastases in the liver, gastrointestinal tract, coelomic cavity, and lungs. CLINICAL RELEVANCE: In birds, pancreatic adenocarcinoma is rarely reported but should be considered a differential diagnosis for hyperamylasemia, coelomic mass, coelomic effusion, or abnormal gastrointestinal signs, alone or in combination. Ultrasonography and CT can be useful in further evaluating such patients and should be considered in the diagnostic plan.