Retrospective evaluation of thoracic computed tomography findings in dogs naturally infected by Angiostrongylus vasorum

Angiostrongylus vasorum (A. vasorum) is an important emerging disease of canidae. Cardiorespiratory signs are common in affected dogs, therefore thoracic imaging is critical for diagnosing andmonitoring disease. Descriptions of thoracic computed tomography (CT) findings in dogs naturallyinfected with A. vasorum are currently lacking. Aims of this multicenter, retrospective study were to describe thoracic CT findings in a group of dogs with confirmed disease, determine whether any changes were consistent among dogs, and propose standardized terms for describing thoracic CT findings. Nine UK-based referral centers’ clinical and imaging databases were searched for dogs that had a confirmed diagnosis of A. vasorum, and had undergone thoracic CT examination. Eighteen dogs, from seven of the centers, fulfilled the inclusion criteria. The lung lobes were divided into the following three zones and the CT changes described in each: pleural (zone 1), subpleural (zone 2), and peribronchovascular (zone 3). The predominent abnormality was increased lung attenuation due to poorly defined ground-glass opacity or consolidation. There were regions of mosaic attenuation due to peripheral bronchiectasis. Nine/18 (50%) dogs showed hyperattenuating nodules of varying sizes with ill-defined margins. The distribution always affected zones 1and 2 with varied involvement of zone 3; this resulted in clear delineation between zones 2 and 3.Tracheobronchial lymphadenomegaly was frequently noted. Findings were nonspecific and there was considerable overlap with other pulmonary conditions. However, authors recommend that A. vasorum be considered a likely differential diagnosis for dogs with a predominantly peripheral distribution of lung changes

A Retrospective Study of Clinical and Histopathological Features of 81 Cases of Canine Apocrine Gland Adenocarcinoma of the Anal Sac: Independent Clinical and Histopathological Risk Factors Associated with Outcome.

Canine apocrine gland anal sac adenocarcinoma (AGASAC) is a malignant tumour with variable clinical progression. The objective of this study was to use robust multivariate models, based on models employed in human medical oncology, to establish clinical and histopathological risk factors of poor survival. Clinical data and imaging of 81 cases with AGASAC were reviewed. Tissue was available for histological review and immunohistochemistry in 49 cases. Tumour and lymph node size were determined using the response evaluation criteria in the solid tumours system (RECIST). Modelling revealed tumour size over 2 cm, lymph node size grouped in three tiers by the two thresholds 1.6 cm and 5 cm, surgical management, and radiotherapy were independent clinical variables associated with survival, irrespective of tumour stage. Tumour size over 1.3 cm and presence of distant metastasis were independent clinical variables associated with the first progression-free interval. The presence of the histopathological variables of tumour necrosis, a solid histological pattern, and vascular invasion in the primary tumour were independent risk factors of poor survival. Based upon these independent risk factors, scoring algorithms to predict survival in AGASAC patients are presented

Comparative study by magnetic resonance imaging, measurement of interstitial pressure and histology

Titelblatt Inhaltsverzeichnis 1: Verwendete Abkürzungen 2 Einleitung und Problemstellung 3 Grundlagen und Literatur 4 Material und Methoden 5 Ergebnisse: MRT 5 Ergebnisse: interstitielle Druckmessung und Histolgie 6 Diskussion 7 Zusammenfassung/8 Summary 9 Literaturverzeichnis 10 Anhang 11 Lebenslauf, 12 Selbstständigkeitserklärung und 13 DanksagungDynamische kontrastmittelgestützte magnetresonanztomographische Untersuchungen solider maligner Tumore zeigen in der Spätphase der Messung das Phänomen des peripheren Washout. Es stellt sich als zunehmend breiter hypointenser Ring in der peripheren Tumorzone dar, während die zentralen Tumoranteile hyperintens verbleiben. Dieses ist spezifisch für maligne Tumore. Interstitielle Druckmessungen zeigen, dass der interstitielle Flüssigkeitsdruck in malignen Tumoren im Gegensatz zum gesunden Gewebe oder benignen Tumoren erhöht ist. Dies liegt unter anderem in der tumorspezifischen Angiogenese und Gefäßmorphologie begründet und hat Auswirkungen auf den Transport von Molekülen innerhalb des Tumorgewebes. Zur Charakterisierung von Tumorgewebe wird der prognostisch aussagefähige Parameter mikrovaskuläre Dichte (MVD) herangezogen. Zielsetzung dieser Arbeit war die Etablierung eines Tiermodells zur Darstellung und Analyse des peripheren Washout, in dem die beeinflussenden Faktoren (interstitieller Flüssigkeitsdruck und histomorphologische Gegebenheiten) im Vergleich zur MRT-Untersuchung beurteilt werden können. Das Modell des Coloncarcinoms der Linie CC531 an der Ratte wurde erfolgreich etabliert. An 21 WAG-Ratten wurde durch die Injektion einer Zellsuspension (1x106 Zellen) der Linie CC531 subkutan das Wachstum des Tumors induziert. Nach 45 Tagen erreichten die Tumore eine Größe von 1,5 - 2 cm im Durchmesser und wurden im MRT (T1-gewichtete 3D-FLASH, TR = 6,8 ms, TE = 2,3 ms, α = 15°, FOV = 125 mm, Matrix = 52 % 100 x 256, Pixelgröße 0,94 x 0,49 mm, Anzahl der Akquisitionen = 1, Blockdicke = 48 mm, effektive Schichtdicke = 6 mm) einer dynamischen Kontrastmitteluntersuchung (42 min) unterzogen. Die Auswertung erfolgte anhand der Messung der relativen Signalintensität in der Vena cava caudalis und vier Tumorzonen (marginal, peripher, intermediär und zentral). In der ersten Messung wurde mit Hilfe des niedermolekularen Gd-DTPA (200 µmol Gd- DTPA/kg) das "periphere Washout" dargestellt, 48 h später erfolgte eine vergleichende MRT-Messung mit dem Blood-Pool Kontrastmittel VSOP-C184 (30 µmol Fe/kg). 24 h später wurde ein Profil des interstitiellen Druckes mit Hilfe der Wick-in-needle (WIN)-Technik erstellt. Anschließend wurden die Tumore entnommen und histologisch zur Charakterisierung des Gewebes mittels Hämatoxylin-Eosin- (HE), zur Prüfung des Eisengehaltes mittels Turnbull-Blau- Färbung (TB) und zur Quantifizierung der Gefäßstrukturen mittels Lektin- Markierung (Griffonia (Bandeiraea) simplicifolia Lektin, BSL I) untersucht. In der MRT-Untersuchung mit Gd-DTPA konnte erstmals das periphere Washout am Coloncarcinom CC531 der Ratte entsprechend dem am Menschen dargestellten Phänomen nachgewiesen und quantitativ analysiert werden. Die neu eingeführte Beurteilung des Verlaufes der Signalintensitäten im Tumor an vier Tumorzonen im Vergleich zur Vena cava caudalis ergab eine eigenständige Charakteristik für jeden der Auswertungsbereiche. Die beiden außen gelegenen Tumorzonen "marginal" und "peripher" zeigten im Vergleich zu den innen gelegenen Tumorzonen "intermediär" und "zentral" grundlegend unterschiedliche Verhaltensmuster im Verlauf der Signalintensität. Während die frühe Intensivierung der Signalintensität auf vaskulären Antransport und Extravasation zurückzuführen ist, können für die späten Signalverstärkungen nur interstitielle Transportprozesse verantwortlich sein. Mit Nachweis des erhöhten interstitiellen Flüssigkeitsdruckes für dieses Modell sind in den Zonen "peripher" und "marginal" Konvektionskräfte entlang des nach außen gerichteten Flüssigkeitsstromes zum Gebiet niederen Druckes im umliegenden Gewebe verantwortlich zu machen. Die Signalintensitätssteigerung der inneren Tumorzonen ist auf eine entgegen gesetzte Diffusionsbewegung des Kontrastmittels im Interstitium zurückzuführen. An diesem Tumormodell wurden erstmalig Messungen mit VSOP-C184 durchgeführt. Sie bestätigten die Ergebnisse aus der Gd-DTPA Messung bezüglich der Perfusion des Tumorgewebes. Es war ebenfalls eine eigenständige Charakteristik aller ausgewerteten Zonen darzustellen. Erstmals wurde für die Kapillaren dieses Tumors gegenüber dem Blood-Pool Kontrastmittel eine, die Extravasation ermöglichende, Permeabilität nachgewiesen. Die Messung des interstitiellen Flüssigkeitsdruckes mit der WIN- Methode wurde für dieses Modell etabliert. Ein Druckprofil wurde erstellt und ein erhöhter interstitieller Flüssigkeitsdruck nachgewiesen, welcher für die Dynamik des Kontrastmittels im Tumor mit verantwortlich ist. In der histologischen Charakterisierung (HE) wurde das Gewebe als maligne eingestuft. In der Eisenfärbung (TB) wurden Hinweise auf Extravasation von VSOP-C184 gefunden. In der glykohistochemischen Färbung (BSL I) konnten erstmals in den Tumorbereichen (Kapsel, minder vaskularisiertes Vitalgewebe, Hotspot und Nekrose) Korrelate zur MRT-Messung wie die mikrovaskuläre Dichte, die Fläche der Gefäßlumina und interkapilläre Distanz ermittelt werden, welche die Ergebnisse der dynamischen MRT-Messung verifizieren. Die Ergebnisse unterstützen die gestellte Hypothese, dass die Ursache für das Auftreten des peripheren Washout am malignen Tumor neben dem tumorspezifischen insuffizienten Gefäßsystem im erhöhten interstiellen Flüssigkeitsdruck begründet liegt. Sie indizieren die Nutzung des peripheren Washout in der Praxis als nicht invasives Malignitätskritierium.Solid malignant tumors display in the end phase of dynamic contrast-enhanced MRI measurements a phenomenon called peripheral washout. It is characterised by the development of a progressively widening, hypointense rim in the tumor's peripheral area, while the central part stays hyperintense. Peripheral washout is specific to malignant tumors. Measurements of interstitial pressure show that, in malignant tumors, the interstitial fluid pressure (IFP) is increased compared to normal tissue and benign tumors. Among other causes, this is due to the tumor-specific angiogenesis and morphology of tumor vessels and affects the transportation of molecules within the tumor. Thus, microvascular density (MVD) is a significant prognostic parameter, and it is used to characterise tumor tissue. The aim of this study was to establish an animal model for the demonstration and analysis of peripheral washout, in which the interacting factors (interstitial fluid pressure and histomorphologic data) could be assessed in relation to MRI. The coloncarcinoma CC531 was successfully established in rats. 21 WAG rats were injected with a cell suspension (1x106) from the experimental cell line CC531 in order to induce subcutaneous growth of coloncarcinoma. After 45 days, the tumors reached diameters of 1,5�2 cm and were subjected to dynamic (42 min) contrast enhanced MRI measurement (T1-weighted 3D-FLASH, TR = 6,8 ms, TE = 2,3 ms, α = 15°, FOV = 125 mm, Matrix = 52 % 100 x 256, pixel dimension = 0,94 x 0,49 mm, number of acquisitions = 1, block thickness = 48 mm, effective slice thickness = 6 mm). Analysis was carried out by measuring the relative signal intensity in the vena cava caudalis compared to four tumor areas (defined as marginal, peripheral, intermediate, central). In the first measurement, peripheral washout was displayed using Gd-DTPA (200 µm Gd-DTPA/kg), a contrast agent with low molecular mass. 48 h later, a comparative measurement was taken using the blood pool contrast agent VSOP-C184 (30 µm Fe/kg). Another 24 h later, a profile of the interstitial fluid pressure was recorded by use of the wick-in- needle (WIN) technique. Subsequently, the tumors were extracted and subjected to tissue characterisation by hematoxylin-eosin-(HE-) staining. They were tested for iron content by turnbull-blue-(TB-) staining and examined for quantifcation of vessel structures by lectin-staining (Griffonia (Bandeiraea) simplicifolia Lectin, BSL I). In the Gd-DTPA MRI study peripheral washout sign was shown for the first time in coloncarcinoma CC531 in rats, analogous to the phenomenon seen in humans. The novel establishment of assessing progression of signal intensity within four tumor areas in comparison to the vena cava caudalis revealed an independent characteristic for each evaluation area. Compared to the two external orientated tumor areas "marginal" and "peripheral", the two internal orientated tumor areas "intermediate" and "central" show entirely different pattern of the progression of signal intensity. While early increase of signal intensity is ascribable to vascular transport and extravasation, later increase of signal intensity is due to interstitial transport processes. With the proof of elevated interstitial fluid pressure for this model external orientated convective fluid movement is in charge for later changes in signal intensity in the areas "peripheral" and "marginal". The later elevation of signal intensity in the inner tumor areas is due to diffusion of contrast agent within the interstitial space. For the first time examinations with VSOP-C184 were carried out on this model. They confirm the results form Gd-DTPA examination referring to perfusion of tumor tissue. Also an independent characteristic progression of signal intensity for each evaluation area was determined. For the first time evidence was found, that the tumor vessels are permeable to the blood pool contrast agent and allow extravasation. For this model measurement of interstitial fluid pressure by WIN-technique was established. The study was able to generate a profile of interstitial fluid pressure and determine elevated interstitial fluid pressure, which is responsible for the dynamics of contrast agent in the tumor. The tissue was rated malignant by histologic characterisation (HE- stain). By iron staining (TB) evidence indicating extravasation of VSOP-C184 was found. By glycohistochemical staining (BSL I) correlates to the MRI-study were found for the first time in the tumor areas (capsule, low vasculated vital tissue, hotspots and necrotic area) like microvascular density, vessel lumina and intercapillary distance, which verify the results from the dynamic MRI-examination. The experimental results support the hypothesis, that peripheral washout in malignant tumors is caused not only by tumor-specific vessel insufficiency, but also by an increased interstitial fluid pressure. They indicate the use of peripheral washout as non invasive criteria of malignancy in practice

Pulmonary angiography with 64-multidetector-row computed tomography in normal dogs

Pulmonary angiography using 64-multidetector-row computed tomography (MDCT) was used to evaluate pulmonary artery anatomy, and determine the sensitivity of pulmonary artery segment visualization in four Beagle dogs using images reconstructed to 0.625 mm and retro-reconstructed to 1.25 and 2.5 mm slice thickness. Morphologically, characteristic features included a focal narrowing in the right cranial pulmonary artery in all dogs, which should not be mistaken as stenosis. While the right cranial pulmonary artery divided into two equally sized branches that were tracked into the periphery of the lung lobe in all dogs, only a single left cranial (cranial portion) lobar artery was present. Compared with 1.25 and 2.5 mm retro-reconstructions, 0.625 mm reconstructions allowed for detection of significantly (P ≤ 0.05) more pulmonary artery segments and sharper depiction of vessel margins. Clinical applications such as prevalence and significance of diameter changes, and detection of pulmonary arterial thrombembolism on lobar and sublobar level, using pulmonary angiography with 64-MDCT applying 0.625 mm reconstruction slice thickness remain to be established

Nocardia arthritidis infection in the distal metaphysis of the metatarsal III and IV bone of a heifer.

CASE DESCRIPTION A 19-month-old 536.4-kg (1,180-lb) Brown Swiss heifer was referred for evaluation of a firm swelling over the distal aspect of the right metatarsal region and chronic lameness in the right hind limb. CLINICAL FINDINGS Examination of radiographs of the right metatarsophalangeal joints revealed an expansile, smoothly marginated, cyst-like lesion within the distal metaphysis of the metatarsal III and IV bone. Differential diagnoses included bone abscess, bone cyst, aneurysmal bone cyst, neoplasia, osteomyelitis, and metabolic bone disease. Aerobic microbial culture of the aspirate yielded moderate growth of branching, gram-positive, rod-shaped bacteria, which were presumptively identified as Nocardia spp. The isolate was subsequently identified as Nocardia arthritidis by 16S rRNA gene sequence analysis. TREATMENT AND OUTCOME The lesion was surgically debrided, lavaged, and bandaged. Exercise was restricted, and systemic and local administration of antimicrobials was instituted. After a communication between the abscess and the metatarsophalangeal joints was iatrogenically created, the extralabel use of aminoglycosides was initiated. The heifer had noticeable clinical improvement within 2 weeks after initial evaluation and reportedly had no evidence of lameness and minimal external blemishes 3 months after the second evaluation. CLINICAL RELEVANCE To our knowledge, this is the first report on the diagnosis and management of a long-bone abscess attributable to N arthritidis infection in cattle. Complications encountered during treatment and the decision to engage in extralabel use of antimicrobial agents in the heifer described here may serve as a guide for food animal practitioners faced with the treatment of valuable cattle

Effects of body position and extension of the neck and extremities on lung volume measured via computed tomography in red-eared slider turtles (Trachemys scripta elegans)

Objective: To determine the effects of body position and extension of the neck and extremities on CT measurements of ventilated lung volume in red-eared slider turtles (Trachemys scripta elegans). Design: Prospective crossover-design study. Animals: 14 adult red-eared slider turtles. Procedures: CT was performed on turtles in horizontal ventral recumbent and vertical left lateral recumbent, right lateral recumbent, and caudal recumbent body positions. In sedated turtles, evaluations were performed in horizontal ventral recumbent body position with and without extension of the neck and extremities. Lung volumes were estimated from helical CT images with commercial software. Effects of body position, extremity and neck extension, sedation, body weight, and sex on lung volume were analyzed. Results: Mean ± SD volume of dependent lung tissue was significantly decreased in vertical left lateral (18.97 ± 14.65 mL), right lateral (24.59 ± 19.16 mL), and caudal (9.23 ± 12.13 mL) recumbent positions, compared with the same region for turtles in horizontal ventral recumbency (48.52 ± 20.08 mL, 50.66 ± 18.08 mL, and 31.95 ± 15.69 mL, respectively). Total lung volume did not differ among positions because of compensatory increases in nondependent lung tissue. Extension of the extremities and neck significantly increased total lung volume (127.94 ± 35.53 mL), compared with that in turtles with the head, neck, and extremities withdrawn into the shell (103.24 ± 40.13 mL). Conclusions and Clinical Relevance: Vertical positioning of red-eared sliders significantly affected lung volumes and could potentially affect interpretation of radiographs obtained in these positions. Extension of the extremities and neck resulted in the greatest total lung volume