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1.
Positron emission tomography/computed tomography (PET/CT) utilizing 3′‐deoxy‐3′‐[18F]fluorothymidine (18FLT), a proliferation tracer, has been found to be a useful tool for characterizing neoplastic diseases and bone marrow function in humans. As PET and PET/CT imaging become increasingly available in veterinary medicine, knowledge of radiopharmaceutical biodistribution in veterinary species is needed for lesion interpretation in the clinical setting. The purpose of this study was to describe the normal biodistribution of 18FLT in adult domestic cats. Imaging of six healthy young adult castrated male cats was performed using a commercially available PET/CT scanner consisting of a 64‐slice helical CT scanner with an integrated whole‐body, high‐resolution lutetium oxy‐orthosilicate (LSO) PET scanner. Cats were sedated and injected intravenously with 108.60 ± 2.09 (mean ± SD) MBq of 18FLT (greater than 99% radiochemical purity by high‐performance liquid chromatography). Imaging was performed in sternal recumbency under general anesthesia. Static images utilizing multiple bed positions were acquired 80.83 ± 7.52 (mean ± SD) minutes post‐injection. Regions of interest were manually drawn over major parenchymal organs and selected areas of bone marrow and increased tracer uptake. Standardized uptake values were calculated. Notable areas of uptake included hematopoietic bone marrow, intestinal tract, and the urinary and hepatobiliary systems. No appreciable uptake was observed within brain, lung, myocardium, spleen, or skeletal muscle. Findings from this study can be used as baseline data for future studies of diseases in cats.  相似文献   

2.
Feline oral squamous cell carcinoma is one of the most refractory feline malignancies. Most patients succumb due to failure in local tumor control. 2‐18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography (18F‐FDG PET) is increasingly being used for veterinary oncology staging as it highlights areas with higher glucose metabolism. The goal of the current prospective study was to compare gross tumor volume measurements using 18F‐FDG PET vs. those using computed tomography (CT) for stereotactic radiation therapy planning in cats with oral squamous cell carcinoma. Twelve cats with confirmed oral squamous cell carcinoma underwent pretreatment 18F‐FDG PET/CT. Gross tumor volumes based on contrast‐enhanced CT and 18F‐FDG PET were measured and compared among cats. Mean PET gross tumor volume was significantly smaller than mean CT gross tumor volume in the mandibular/maxillary squamous cell carcinoma group (n = 8, P = 0.002) and for the total number of patients (n = 12, P = 0.006), but not in the lingual/laryngeal group (n = 4, P = 0.57). Mismatch fraction analysis revealed that most of the lingual/laryngeal patients had a large region of high‐18F‐FDG activity outside of the CT gross tumor volume. This mismatch fraction was significantly greater in the lingual/laryngeal group than the mandibular/maxillary group (P = 0.028). The effect of poor spatial resolution of PET imaging was greater when the absolute tumor volume was small. Findings from this study indicated that 18F‐FDG PET warrants further investigation as a supplemental imaging modality in cats with oral squamous cell carcinoma because it detected regions of possible primary tumor that were not detected on CT images.  相似文献   

3.
Functional imaging using positron emission tomography (PET) plays an important role in the diagnosis, staging, image‐guided treatment planning and monitoring of malignant diseases. PET imaging complements conventional anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI). The strength of CT scanning lies in its high spatial resolution, allowing for anatomical characterization of disease. PET imaging, however, moves beyond anatomy and characterizes tissue based on functions such as metabolic rate. Combined PET/CT scanners were introduced commercially in 2001 and a number of technological advancements have since occurred. Radiolabelled tracers such as 18F‐fluorodeoxyglucose (FDG) and 18F‐fluorothymidine (FLT) allow visualization of various metabolic processes within cancer cells. Many studies in human oncology evaluating the utility of PET/CT have demonstrated clinical benefits. Few veterinary studies have been performed, but initial studies show promise for improved detection of malignancy, more thorough staging of canine cancer and determination of early response and disease recrudescence.  相似文献   

4.
Fever of unknown origin (FUO) is a persistent or recurrent fever for which the underlying source has not been identified despite diagnostic investigation. In people, 18F‐fluoro‐2‐deoxyglucose positron emission tomography (18F‐FDG‐PET) alone or in combination with computed tomography (CT) is often beneficial in detecting the source of fever when other diagnostics have failed. Veterinary reports describing use of these modalities in animals with fever of unknown origin are currently lacking. Aims of this retrospective case series were to describe 18F‐FDG‐PET or 18F‐FDG‐PET/CT findings in a group of dogs with fever of unknown origin. Dogs presenting to a single center between April 2012 and August 2015 were included. A total of four dogs met inclusion criteria and underwent either positron emission tomography (n = 2) or positron emission tomography/CT (n = 2) as a part of their diagnostic investigation. All subjects underwent extensive diagnostic testing prior to 18F‐FDG‐PET/CT. Initial diagnostic evaluation failed to identify either a cause of fever or an anatomic location of disease in these four dogs. In each dog, positron emission tomography or positron emission tomography/CT was either able to localize or rule out the presence of focal lesion thereby allowing for directed sampling and/or informed disease treatment. Follow up 18F‐FDG‐PET/CT scans performed in two patients showed improvement of observed abnormalities (n = 1) or detected recurrence of disease allowing for repeated treatment before clinical signs recurred (n = 1). Fever resolved after specific treatment in each dog. Findings from the current study supported the use of positron emission tomography or positron emission tomography/CT as adjunctive imaging modalities for diagnosis and gauging response to therapy in dogs with fever of unknown origin.  相似文献   

5.
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6.
Positron emission tomography (PET) is often used to stage and monitor human cancer and has recently been used in a similar fashion in veterinary medicine. The most commonly used radiopharmaceutical is 2‐Deoxy‐2‐[18F]‐Fluoro‐d ‐glucose (18F‐FDG), which is concentrated and trapped within cells that use glucose as their energy substrate. We characterized the normal distribution of 18F‐FDG in 10 healthy Hispaniolan Amazon parrots (Amazona ventralis) by performing whole body PET scans at steady state, 60 min after injection. Significant variability was found in the intestinal activity. Avian species are known to reflux fluid and electrolytes from their cloaca into their colon. To evaluate reflux as the cause of variability in intestinal distribution of 18F‐FDG, dynamic PET scans were performed on the coelomic cavity of six Hispaniolan Amazon parrots from time 0 to 60 min postinjection of radiotracer. Reflux of radioactive material from the cloaca into the colon occurred in all birds to varying degrees and occurred before 60 min. To evaluate the intestinal tract of clinical avian patients, dynamic scans must be performed starting immediately after injection so that increased radioactivity due to metabolism or hypermetabolic lesions such as cancer can be differentiated from increased radioactivity due to reflux of fluid from the cloaca.  相似文献   

7.
The goal of this prospective pilot study was to use naturally occurring canine mast cell tumors of various grades and stages as a model for attempting to determine how glucose uptake and markers of biologic behavior are correlated. It was hypothesized that enhanced glucose uptake, as measured by 2‐[fluorine‐18]fluoro‐d ‐glucose‐positron emission tomography/computed tomography (F18 FDG PET‐CT), would correlate with histologic grade. Dogs were recruited for this study from a population referred for treatment of cytologically or histologically confirmed mast cell tumors. Patients were staged utilizing standard of care methods (abdominal ultrasound and three view thoracic radiographs), followed by a whole body F18 FDG PET‐CT. Results of the F18 FDG PET‐CT were analyzed for possible metastasis and standard uptake value maximum (SUVmax) of identified lesions. Incisional or excisional biopsies of the accessible mast cell tumors were obtained and histology performed. Results were then analyzed to look for a possible correlation between the grade of mast cell tumors and SUVmax. A total of nine animals were included in the sample. Findings indicated that there was a correlation between grade of mast cell tumors and SUVmax as determined by F18 FDG PET‐CT (p‐value = 0.073, significance ≤ 0.1). Based on the limited power of this study, it is felt that further research to examine the relationship between glucose utilization and biologic aggressiveness in canine mast cell tumors is warranted. This study was unable to show that F18 FDG PET‐CT was a better staging tool than standard of care methods.  相似文献   

8.
The aim of this study was to evaluate if hypoxia in feline fibrosarcomas can be detected. This was done using positron emission tomography (PET), two hypoxia tracers and polarographic pO2 measurements. Of the seven cats included, five received [18F]‐fluoromisonidazole and two 2‐(2‐nitro‐1H‐imidazol‐1‐yl)‐N‐(2,2,3,3,3‐pentafluoropropyl) acetamide. Perfusion was evaluated with [15O]‐H2O (n = 4) and with contrast‐enhanced power Doppler ultrasonography (n = 5). Hypoxia was detected in three cats. Polarographic pO2 measurements did not confirm PET results. In the ultrasonographic evaluation, low vascularity and low perfusion were seen with a peripheral vascular pattern and no perfusion in the centre of the tumour. This was in contrast to the [15O]‐H2O scans, where central perfusion of the tumour was also found. In conclusion, it appears that hypoxia exists in this tumour type. The presence of tumour necrosis and heterogeneous hypoxia patterns in these tumours may explain the found discrepancies between the applied techniques.  相似文献   

9.
Imaging and measurement of proliferation with computed tomography (CT) and positron emission tomography (PET) provide a noninvasive method for improved staging and monitoring of response to cancer treatment. We evaluated prospectively the proliferation marker 3'-deoxy-3'[18F] fluorothymidine (FLT) in the context of FLT-PET/CT for detection of early response, confirmation of posttreatment response, and prediction of relapse in dogs with non-Hodgkin's lymphoma. Nine dogs with non-Hodgkin's lymphoma who were scheduled to receive five cycles of an investigational cytotoxic chemotherapy agent were included. All dogs received baseline FLT-PET/CT imaging immediately before chemotherapy. Intent was to repeat imaging with FLT-PET/CT at various time points: group 1 ( n =4), 5 days after initiation of chemotherapy and 3 weeks following the last chemotherapy administration; group 2 ( n =5), before the fourth cycle of chemotherapy and 3 weeks following the last administration. Two dogs in group 2 did not undergo repeat PET/CT. Body mass standardized uptake values (SUV) for FLT were calculated for each dog. Eight dogs had initially increased FLT uptake (mean SUVmax=9.8 [2.6–22.3]). Mean SUV decreased significantly for the seven dogs that underwent follow-up PET/CT following chemotherapy (mean SUVmax=3.5 [1.1–7.9], P <0.016). Increased uptake preceded clinical and cytological evidence of relapse in two dogs. Ki-67 immunohistochemistry confirmed decreased proliferation corresponding to decreased SUV in three canine lymph node samples. FLT-PET/CT functional and anatomical imaging shows promise for the evaluation of response to cytotoxic chemotherapy in dogs with non-Hodgkin's lymphoma and for predicting relapse before standard clinical and clinicopathologic confirmation.  相似文献   

10.
A 5‐year‐old female spayed bulldog was referred for mild dyspnea, decreased activity and appetite, occasional nonproductive cough, polydipsia, and polyuria. A 2‐deoxy‐2‐[18F]fluoro‐D‐glucose (FDG) positron emission tomography/computed tomography (PET/CT) scan revealed unexpected activity in the heart, lungs, and mild generalized lymphadenopathy that led to the diagnosis of lymphoma of granular lymphocytes after nonspecific findings on imaging with standard modalities of echocardiography, thoracic radiography, and abdominal ultrasound. PET/CT scanning is a useful whole body imaging modality with high sensitivity for changes associated with canine lymphoma.  相似文献   

11.
Imaging‐assisted orthopaedic surgery is becoming part of routine orthopaedic practice in horses and several techniques have been reported. However, there are no published reports describing the use of intraoperative computed tomography (CT) for surgical guidance and immediate post operative control in the horse. This use of CT in equine orthopaedics is currently limited because of the logistic problems associated with availability of CT scans in surgical theatres as well as concerns over radiation safety. The aim of this report was retrospectively to report CT assisted orthopaedic surgical cases in our practice through identifying the types of surgery where it was used, to list the technical problems that were encountered, to describe solutions to these, and to discuss the applications of the technique. All surgical procedures were performed with the assistance of a peripheral quantitative computed tomography (pQCT) scanner. CT assisted orthopaedic surgery in 86 patients during the study period. Reasons for CT included: 1) use of CT at the beginning of the surgical procedure to document the lesion and identify surgical landmarks (n = 75); 2) pre, intra‐ and post operative use of CT in comminuted fractures of the middle or proximal phalanx to guide and control internal fixation (n = 7); and 3) post operative use of CT to monitor the results of the surgical procedure (n = 4). Proper planning in both the draping steps and the use of polyvinyl splints to stabilise the limb allowed for movements of the gantry around the limb. The time required to obtain one slice was not dissimilar to the time that is necessary to take and process a single digital radiograph. The radiation dose with the pQCT described here is <0.5 µSv and its acquisition time should be balanced against radiation risks of conventional CT systems.  相似文献   

12.
18F‐fluorodeoxyglucose positron emission tomography combined with computed tomography (18FDG‐PET/CT) has been shown to be effective for staging human oral squamous cell carcinoma (SCC) but its application for cats with oral SCC is unknown. Twelve cats with biopsy‐proven oral SCC were imaged with whole body 18FDG‐PET/CT to determine its value as a diagnostic imaging and staging tool and fine needle aspirates were obtained of accessible regional lymph nodes. All tumors were FDG avid and conspicuous on 18FDG‐PET/CT images, with an average of the maximum standardized uptake value 9.88 ± 5.33 SD (range 2.9–24.9). Soft tissue infiltrative tumors that were subtle and ill defined on CT were highly visible and more extensive on FDG‐PET/CT. Tumors invading the osseous structures were more similar in extent on 18FDG‐PET/CT and CT although they were more conspicuous on PET images. Three cytologically confirmed metastases were hypermetabolic on PET, while two of those metastases were equivocal on CT.  相似文献   

13.
This retrospective, methods comparison study aimed to compare skeletal scintigraphy and 18F-NaF positron emission tomography (PET) for the detection of abnormalities in the fetlocks of Thoroughbred racehorses. Thirty-three horses (72 limbs) imaged with both scintigraphy and 18F-NaF PET, for investigation of lameness or poor performance related to the fetlock, were included. Seven observers, including experienced racetrack practitioners, surgery and imaging residents, and a board-certified veterinary radiologist, independently reviewed all data for evidence of increased radiopharmaceutical uptake in 10 different regions of interest. The interobserver agreement was higher for PET (Kappa-weighted (K-w) 0.73 (0.51–0.84)) (median (range)) than for scintigraphy (0.61 (0.40–0.77)) (P < 0.0001). When scintigraphy and PET were compared, the agreement was fair (K-w 0.29). More sites of increased uptake were identified using PET compared with scintigraphy. Agreement between the two modalities was higher for the palmar/plantar metacarpal/metatarsal condylar regions (K-w 0.59) than for the proximal sesamoid bones (K-w 0.25). Increased radiopharmaceutical uptake was detected in the medial proximal sesamoid bone in 6.9% and 22.2% of limbs with scintigraphy and PET, respectively. The high interobserver agreement for PET, despite the recent introduction of this technique, demonstrates the ease of clinical interpretation of PET scans. The higher number of lesions detected with PET compared with scintigraphy can be explained by the higher spatial resolution and cross-sectional nature of this modality. Study findings supported using PET in a clinical population of racehorses, in particular for the assessment of the proximal sesamoid bones.  相似文献   

14.
We evaluated the whole body distribution of 2‐deoxy‐2‐[18F]fluoro‐d ‐glucose (18F‐FDG) in seven beagle dogs using positron emission tomography/computed tomography. The mean and maximum standard uptake values (SUV) for various tissues were computed. The SUV of the aortic blood pool was 0.65±0.19. Moderate uptake was present in brain (3.40±1.01). Mild uptake was present in orbital muscles, soft palate, laryngeal and pharyngeal region, mandibular salivary gland, myocardium, liver, pancreas, kidney, and intestine. 18F‐FDG uptake would be normally higher in these tissues because of normal physiologic activity. Mean and maximum SUV values of the eye, skeletal muscle, bone tissue, spleen, adrenal gland, stomach, tongue, gall bladder, and lung were similar to or lower than that of the aortic blood pool. These data provide a normal baseline for comparing pathologic 18F‐FDG uptake.  相似文献   

15.
A nine‐year‐old intact female domestic shorthair cat was evaluated for paraparesis, ataxia and severe spinal hyperaesthesia. Neurological examination indicated a T3‐L3 spinal cord segment lesion. Computed tomography of the thoracolumbar and lumbosacral vertebral column was performed. This showed contiguous smooth new bone formation ventral and lateral to the vertebrae extending from the cranial thoracic area to the lumbosacral junction and appearing similar to canine diffuse idiopathic skeletal hyperostosis. There was also marked dorsolateral stenosis of the vertebral canal at the level of T4‐T5 because of degenerative changes of the facet joints. To the authors’ knowledge, this is the first published report of feline diffuse idiopathic skeletal hyperostosis.  相似文献   

16.
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17.
The purpose of this study was to assess the effects of four anesthetic protocols on normal canine brain uptake of 2‐deoxy‐2‐[18F]fluoro‐d ‐glucose (FDG) using positron emission tomography/computed tomography (PET/CT). Five clinically normal beagle dogs were anesthetized with (1) propofol/isoflurane, (2) medetomidine/pentobarbital, (3) xylazine/ketamine, and (4) medetomidine/tiletamine–zolazepam in a randomized cross‐over design. The standard uptake value (SUV) of FDG was obtained in the frontal, parietal, temporal and occipital lobes, cerebellum, brainstem and whole brain, and compared within and between anesthetic protocols using the Friedman test with significance set at P<0.05. Significant differences in SUVs were observed in various part of the brain associated with each anesthetic protocol. The SUV for the frontal and occipital lobes was significantly higher than in the brainstem in all dogs. Dogs receiving medetomidine/tiletamine–zolazepam also had significantly higher whole brain SUVs than the propofol/isoflurane group. We concluded that each anesthetic protocol exerted a different regional brain glucose uptake pattern. As a result, when comparing brain glucose uptake using PET/CT, one should consider the effects of anesthetic protocols on different regions of the glucose uptake in the dog's brain.  相似文献   

18.
Regional cerebral metabolism and blood flow can be measured noninvasively with positron emission tomography (PET). 2‐[18F]fluoro‐2‐deoxy‐D‐glucose (FDG) widely serves as a PET tracer in human patients with epilepsy to identify the seizure focus. The goal of this prospective study was to determine whether juvenile or adult dogs with focal‐onset epilepsy exhibit abnormal cerebral glucose uptake interictally and whether glucose uptake changes with age. We used FDG‐PET to examine six Lagotto Romagnolo dogs with juvenile epilepsy, two dogs with adult‐onset epilepsy, and five control dogs of the same breed at different ages. Three researchers unaware of dog clinical status visually analyzed co‐registered PET and magnetic resonance imaging (MRI) images. Results of the visual PET analyses were compared with electroencephalography (EEG) results. In semiquantitative analysis, relative standard uptake values (SUV) of regions of interest (ROI) drawn to different brain regions were compared between epileptic and control dogs. Visual analysis revealed areas of hypometabolism interictally in five out of six dogs with juvenile epilepsy in the occipital, temporal, and parietal cortex. Changes in EEG occurred in three of these dogs in the same areas where PET showed cortical hypometabolism. Visual analysis showed no abnormalities in cerebral glucose uptake in dogs with adult‐onset epilepsy. Semiquantitative analysis detected no differences between epileptic and control dogs. This result emphasizes the importance of visual analysis in FDG‐PET studies of epileptic dogs. A change in glucose uptake was also detected with age. Glucose uptake values increased between dog ages of 8 and 28 weeks and then remained constant.  相似文献   

19.
Glomerular filtration rate (GFR), an important parameter of renal function, is difficult to assess clinically. Serum creatinine and blood urea nitrogen measurements lack sensitivity, whereas radionuclide determination of GFR is not always available and requires postinjection patient isolation. GFR can be determined using computed tomography (CT), most commonly via Patlak plot analysis. Four adult cats, two adult dogs, and a foal underwent abdominal CT under general anesthesia for various diseases of the upper urinary tract. CT‐GFR was measured with a single‐slice dynamic acquisition and Patlak plot analysis. In five animals, the total CT‐GFR appeared to be below normal, corresponding with mild (two animals) and moderate (two animals) increases of serum creatinine in four. In the two animals with normal or increased CT‐GFR, serum creatinine was within the reference values. A significant negative logarithmic relationship was found between CT‐GFR and serum creatinine values (P=0.008; r2=0.75). No complications occurred during or following CT‐GFR. CT examination provided clinically relevant information in 3/5 patients with possible ureteral obstruction and in 3/3 patients with suspected ureteral calculi. Single‐slice dynamic CT‐GFR was practical and provided clinically useful information in this small series of patients undergoing CT of the upper urinary tract. There was a significant relationship between CT‐GFR and serum creatinine values, which supports the clinical potential of CT‐GFR and justifies further investigation of this technique.  相似文献   

20.
The effect of β‐carotene supplementation upon luteal activity, measured as number (CLT) and volume (VLT) of corpus luteum, and P4 synthesis in goats, was evaluated. Goats (n = 22, 34 months) were randomly assigned to one of two experimental groups: (i) β‐carotene [Beta, n = 10; body weight (BW = 44.8 ± 1.45 kg), body condition score (BCS = 3.25 ± 0.07)], and (ii) Control (Control, n = 12; BW = 45.30 ± 1.32 kg, BCS = 3.33 ± 0.06). Upon oestrus synchronization, the Beta group received 50 mg of β‐carotene per day during 35 days pre‐ and 17 days post‐ovulation. The day 4, 8, 12 and 16 post‐ovulation, blood samples were collected for quantification of serum P4 concentrations by radioimmmunoassay, and transrectal ultrasonographic scanning was performed at day 18 for evaluating CLT and VLT. Overall, CLT and VLT mean were 3.10 and 2211.1 mm3 respectively. The Beta‐goats depicted both the largest values for CLT (p = 0.07) and serum P4 levels (p = 0.05), with no differences (p = 0.53) for VLT between treatments. Results suggest a higher efficiency within the cellular‐enzymatic groups defining the steroidogenic pathways in the β‐carotene‐supplemented goats, generating a larger P4 synthesis. The last is essential for ovulation of healthy oocytes, maintenance of uterine quiescence, nourishment and survival of the embryo around implantation; all of them of paramount significance during the maternal recognition of pregnancy process.  相似文献   

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