Comparison of image quality and in vivo appearance of the normal equine nasal cavities and paranasal sinuses in computed tomography and high field (3.0 T) magnetic resonance imaging

Use of a novel helical fan beam imaging system for computed tomography of the head and neck in sedated standing horses: 120 cases (2019–2020)

OBJECTIVE

To evaluate the diagnostic capabilities of a novel helical fan beam CT system used for imaging of horses with clinical problems of the head and neck.

ANIMALS

120 horses.

PROCEDURES

Medical records were reviewed of horses presented for CT of the head or neck at 2 university hospitals. The following data were recorded: age, sex, breed, presenting complaint, sedation used for imaging, scanning time, procedure time, other diagnostic imaging methods performed, imaging diagnosis, clinical diagnosis, and complications during imaging.

RESULTS

Quarter Horses and Warmbloods were the most common breeds, and the most common complaint was nasal discharge. The head (101/120 [84%] horses) was scanned most frequently, and the most common diagnoses were primary dental disease and a space-occupying lesion of the paranasal sinuses. Nuchal bursitis was the most common imaging diagnosis in the neck region. Procedure time ranged from 20 to 45 minutes with a scanning time of 30 to 40 seconds. No complications with horse sedation occurred, and horses tolerated scanning well. An imaging diagnosis was more frequently achieved with CT (109/120 [91%] horses) than with planar digital radiography (23/61 [38%] horses).

CLINICAL RELEVANCE

The helical fan beam CT system had fast scanning times and could be used safely for routine imaging of the teeth and sinuses in horses. The caudal extent of scanning in the neck region was limited by the shape of the horse’s neck and thorax.

3T Magnetic resonance imaging and computed tomography of the bovine carpus

Background

Lameness in cattle is a major health problem and causes great economic losses. Carpal injury is a common cause of forelimb lameness in cattle. Radiography and/or ultrasonography of the carpus is a challenge due to complex anatomy of the joint. Additional imaging using computed tomography (CT) or magnetic resonance imaging (MRI) may be indispensable for reaching a decisive diagnosis. Precise evaluation of the clinical CT and MRI images necessitates an in-depth knowledge of the normal CT and MRI tissue variants. Therefore, our purpose was to provide a detailed description of the normal CT and MRI appearance of the osseous and soft tissue structures of twelve cadaveric bovine carpi using CT and 3 Tesla MRI. Carpi were frozen, transected in sagittal, dorsal and transverse planes then adjoined to their corresponding CT and MRI images.

Results

The clinically significant articular and peri-articular structures of the bovine carpus were identified and characterized on the CT and MRI images. CT images provided a remarkable delineation of the cortical, subchondral, and cancellous bone. The high-field 3 Tesla MRI offered high definition and distinction of the delicate soft tissues of the bovine carpus.

Conclusions

3 Tesla high-field MRI offers new opportunities in soft tissue tomography but cannot be compared with CT in terms of bone imaging. Clinicians have to determine whether CT, MRI or both imaging techniques are required in clinical situations.

Radiography, CT, and MRI Diagnosis of Enzootic Nasal Tumor in Goats Infected With Enzootic Nasal Tumor Virus

The aim of this study was to describe radiography, computed tomography (CT), and magnetic resonance imaging (MRI) findings of enzootic nasal tumors in goats infected with enzootic nasal tumor viruses. Five of six goats with a mean age of 2 years, showed clinical signs of respiratory disease. Head radiographs showed increased density of the unilateral or bilateral nasal cavity in four goats, and a CT scan showed that the space-occupying lesion of the nasal cavity originated from the ethmoid bone and was enhanced homogeneously postcontrast in all goats. The nasal concha was destroyed and the paranasal sinus mucosa was thickened and filled with fluid in some goats. On MRI, the mass exhibited equal or slightly higher signal intensity on T2 weighted images, equal signal intensity on T1 weighted images, a high signal on fluid-attenuated inversion recovery images and heterogeneous enhancement postcontrast. After dissection, histopathological examination of the mass and virus genome detection of the nasal secretions confirmed that the intranasal mass was a low-grade adenocarcinoma and that the goats were infected with enzootic nasal tumor virus type 2. In conclusion, CT and MRI have high diagnostic values for enzootic nasal tumors because they match the postmortem findings and are more accurate than radiography.

Magnetic Resonance Imaging Images under Deep Learning in the Identification of Tuberculosis and Pneumonia

This work aimed to explore the application value of deep learning-based magnetic resonance imaging (MRI) images in the identification of tuberculosis and pneumonia, in order to provide a certain reference basis for clinical identification. In this study, 30 pulmonary tuberculosis patients and 27 pneumonia patients who were hospitalized were selected as the research objects, and they were divided into a pulmonary tuberculosis group and a pneumonia group. MRI examination based on noise reduction algorithms was used to observe and compare the signal-to-noise ratio (SNR) and carrier-to-noise ratio (CNR) of the images. In addition, the apparent diffusion coefficient (ADC) value for the diagnosis efficiency of lung parenchymal lesions was analyzed, and the best b value was selected. The results showed that the MRI image after denoising by the deep convolutional neural network (DCNN) algorithm was clearer, the edges of the lung tissue were regular, the inflammation signal was higher, and the SNR and CNR were better than before, which were 119.79 versus 83.43 and 12.59 versus 7.21, respectively. The accuracy of MRI based on a deep learning algorithm in the diagnosis of pulmonary tuberculosis and pneumonia was significantly improved (96.67% vs. 70%, 100% vs. 62.96%) (P < 0.05). With the increase in b value, the CNR and SNR of MRI images all showed a downward trend (P < 0.05). Therefore, it was found that the shadow of tuberculosis lesions under a specific sequence was higher than that of pneumonia in the process of identifying tuberculosis and pneumonia, which reflected the importance of deep learning MRI images in the differential diagnosis of tuberculosis and pneumonia, thereby providing reference basis for clinical follow-up diagnosis and treatment.

Description of normal head structures of the one-humped camel (Camelus dromedarius) by magnetic resonance imaging, computed tomography, and cross-sectional anatomy

Aim:

This study was designed for the 1^st time to describe the normal head structures of one-humped camel (Camelus dromedarius) using both magnetic resonance imaging (MRI) and computed tomography (CT) as well as cross-sectional anatomy.

Materials and Methods:

Five fresh cadaver heads were collected from clinically normal camels and then subjected to T1-weighted MR and CT imaging. Afterward, these examined heads were transversely sliced to obtain seven crossing levels.

Results:

The obtained structures per each crossing level were matched with their relevant sorted images of T1-weighted MRI and CT, then identified and labeled accordingly.

Conclusion:

The data shown herein expand our knowledge of the normal head structures of the camel and could be used as a reference for ultimate diagnosis of the surgical affections of head using MRI and/or CT.

Comparative studies on the histological characteristics of equine nasomaxillary aperture and paranasal sinus mucosa considering topographic and age-related differences

Background

Horses may acquire a range of paranasal sinus diseases. Clinical studies show slight differences regarding anatomical regions and age. Histopathological examination of tissue samples could play an important role in the diagnostic process. Therefore, detailed knowledge of the histological appearance of the paranasal sinus mucosa (PSM) and the nasomaxillary aperture mucosa (NAM) is essential. The objective of this study was to determine topographic and age-related differences within the healthy equine PSM. In addition, we aimed to gain detailed knowledge of the histological appearance of the NAM in comparison to the PSM.

Results

The PSM had an average height of 75.72 ± 44.48 μm with a two-row pseudostratified columnar epithelium of 13.52 ± 4.78 μm. The parameters mucosal height, epithelial height and number of goblet cells revealed significant dependency of the sample site and age group. The maxillary and dorsal conchal sinus showed the highest values for these parameters. In terms of age, younger horses showed a significantly higher total mucosal height in contrast to a significantly lower epithelial height than older horses. Positive correlation was seen between the epithelial height and number of goblet cells. The NAM had an average height of 820.27 ± 653.21 μm. Its pseudostratified epithelium was usually arranged in three rows and had an average height of 44.9 ± 12.78 μm. The number of goblet cells in the NAM was five times higher than in the PSM. Serous glands were found in only 4% of the PSM samples and 100% of the NAM samples.

Conclusions

There are significant histological differences between different paranasal sinus sites and between different groups of age. This may be related to an altered susceptibility for certain pathologies. The striking difference in the histological appearance of the NAM compared to the PSM could be due to an enhanced role in mucociliary clearance. Further studies are necessary to improve the understanding of mucosal function in specific paranasal sinus compartments and mucosal changes generated by different diseases.

Magnetic resonance imaging and computed tomography of equine cheek teeth and adjacent structures: comparative study of image quality in horses in vivo, post-mortem and frozen-thawed

BACKGROUND

The use of cadavers for radiology research methodologies involving subjective image quality evaluation of anatomical criteria is well-documented. The purpose of this method comparison study was to evaluate the image quality of dental and adjacent structures in computed tomography (CT) and high-field (3 T) magnetic resonance (MR) images in cadaveric heads, based on an objective four-point rating scale. Whilst CT is a well-established technique, MR imaging (MRI) is rarely used for equine dental diagnostics. The use of a grading system in this study allowed an objective assessment of CT and MRI advantages in portraying equine cheek teeth. As imaging is commonly performed with cadaveric or frozen and thawed heads for dental research investigations, the second objective was to quantify the impact of the specimens' conditions (in vivo, post-mortem, frozen-thawed) on the image quality in CT and MRI.

RESULTS

The CT and MR images of nine horses, focused on the maxillary premolar 08s and molar 09s, were acquired post-mortem (Group A). Three observers scored the dental and adjacent tissues. Results showed that MR sequences gave an excellent depiction of endo- and periodontal structures, whereas CT produced high-quality images of the hard tooth and bony tissues. Additional CT and MRI was performed in vivo (Group B) and frozen-thawed (Group C) in three of these nine horses to specify the condition of the best specimens for further research. Assessing the impact of the specimens' conditions on image quality, specific soft tissues of the maxillary 08s and 09s including adjacent structures (pulps, mucosa of the maxillary sinuses, periodontal ligament, soft tissue inside the infraorbital canal) were graded in group B and C and analysed for significant differences within CT and MR modalities in comparison to group A. Results showed that MRI scores in vivo were superior to the post-mortem and frozen-thawed condition.

CONCLUSIONS

On comparing the imaging performance of CT and MRI, both techniques show a huge potential for application in equine dentistry. Further studies are needed to assess the clinical suitability of MRI. For further research investigations it must be considered, that the best MR image quality is provided in live horses.

Magnetic resonance dacryocystography in the horse: A feasibility study

OBJECTIVE

To provide a comprehensive anatomical description of the normal equine nasolacrimal duct using magnetic resonance imaging, and to develop a practical protocol for performing magnetic resonance dacryocystography (MRD) in horses.

ANIMAL STUDIED

The heads of ten fresh horse cadavers with no history of sinonasal or ophthalmologic disorders were used for this study.

PROCEDURE

An MRD technique was developed in this study, which consisted of two parts. In the first part, olive oil and gadolinium were compared as contrast medium, using five horses. Two concentrations of gadolinium were used: 0.25 mmol/mL and 0.5 mmol/mL. In the second part, the influence of different head recumbencies using olive oil as the sole contrast medium was studied in the remaining five horses.

RESULTS

Injection with olive oil resulted in better distention and a complete filling of the nasolacrimal duct (ND) in all horses. Injection of 0.25 mmol/mL of gadolinium resulted in incomplete filling of the ND, whereas injection of 0.5 mmol/mL of gadolinium resulted in slightly better filling of the duct. The nondependent duct showed better distention compared to the dependent duct when scanning in lateral recumbency. No differences were observed between ducts in a dorsal recumbency. The degree of distention in dorsal recumbency was slightly less than the degree of distention observed in the nondependent ND in lateral recumbency.

CONCLUSIONS

Magnetic resonance dacryocystography is a suitable technique for evaluating the nasolacrimal duct and can be performed during a normal magnetic resonance examination.

Validation of a 2-mm videoendoscope for the evaluation of the paranasal sinuses with a minimally invasive technique

OBJECTIVE

To describe the technique, experience, and limitations of using a 2-mm flexible endoscope to perform standing minimally invasive sinoscopy.

STUDY DESIGN

In phases 1 and 2, we used cadaveric heads (ex vivo). In phase 3, we used unaffected horses (in vivo).

ANIMALS

Five cadaveric equine skulls in phase 1 and 10 cadaveric equine skulls in phase 2. Six horses older than 5 years in phase 3.

METHODS

In phase 1, the specimens were used to determine the suitability of the endoscope for sinoscopy and the ideal landmarks to approach the paranasal sinuses through minisinusotomies performed with a 14 gauge needle. In phase 2, a nonblinded evaluation of the visualization of the different sinus compartments was performed, and a score was attributed to each structure. Procedures were video recorded and compared with direct visualization of the sinuses after performing frontal and maxillary flaps. In phase 3, the technique was validated in healthy horses under sedation.

RESULTS

The landmarks determined in phase 1 allowed a thorough exploration of the sinuses in phases 2 and 3. Sinoscopy findings were confirmed after direct visualization of the sinuses via frontal and maxillary bone flaps in phase 2. The procedure was well tolerated by all horses.

CONCLUSION

Minimally invasive sinoscopy was readily performed without relevant complications in standing horses. A thorough evaluation of most sinus structures was obtained only using the frontal and the rostral maxillary portals.

CLINICAL SIGNIFICANCE

Minimally invasive sinoscopy offers an alternative diagnostic tool to veterinarians. A specialized endoscope and appropriate training are required to perform this minimally invasive procedure.

Cytological Examination of Secretions From the Paranasal Sinuses in Horses

The objective of this study was to determine whether the assessment of cytological features of secretions from the paranasal sinuses represents a useful diagnostic tool in equine sinusitis to distinguish between different etiologies. Secretion samples from 50 horses with sinusitis and 10 healthy horses were taken transendoscopically from the drainage angle of the nasomaxillary aperture using a Swing Tip catheter. An additional direct sample from the caudal maxillary sinus was taken from all healthy horses after trephination. A direct sample was obtained from the affected sinus in 19 diseased horses after osteotomy. Samples were smeared on microscope slides and dyed using "Pappenheim stain" for cytological evaluation. Smears from horses with sinusitis (primary n = 14, dental n = 28, cyst n = 2, progressive ethmoidal hematoma [PEH] n = 2, traumatic n = 2, malignant neoplasia n = 2) were dominated by moderate to high numbers of neutrophilic granulocytes and moderate numbers of different epithelial cells, whereas samples from healthy sinuses revealed almost exclusively epithelial cells. Smears in dental-related sinusitis tended to contain more lytic cellular material than in other conditions. Horses with dental sinusitis also showed a higher intracellular and extracellular bacterial burden than horses with other underlying etiologies and healthy horses. The absence of bacteria in light microscopy did not exclude the evidence of pathogenic bacteria from bacterial culture in every case. Case numbers were too small to evaluate the diagnostic value for neoplastic conditions or PEH. In conclusion, cytological examination of secretions from the paranasal sinuses can provide an additional but limited ancillary diagnostic value in equine sinusitis.