Photoacoustic Imaging: Hybrid Technology for Small Animals Holding Potentials Translatable for Clinical applications

Photoacoustic imaging is an emerging modality that exploits the photoacoustic effect to combine the high contrast of optical imaging with the spatial resolution and penetration depth of ultrasound. A key feature of PA imaging methods is that they exploit optical contrast but employ US detection principles. The PA effect offers a way to take advantage of the ability of light to penetrate into the body and let us defeat light diffusion by using US waves to see the penetrating light. The main advantage of this hybrid approach is that the optical properties of biological tissue, including high contrast and spectral specificity, are encoded in an ultrasound signal. Resolutions of better than 1 mm can be obtained at depths measured in centimeters (up to 7) and not in millimeters, depending on the laser wavelength and transducer frequency used, opening up entirely new regimens of optical imaging. From a clinical standpoint, PA imaging is complementary in nature and synergetic with US and a combined US and PA imaging system can be easily implemented due to the presence of a shared detector and associated electronics. Furthermore, such a system will be readily accepted by clinicians familiar with US imaging

Harmonic technology versus neodymium-doped yttrium aluminium garnet laser and electrocautery for lung metastasectomy: An experimental study

We compared the efficacy of non-anatomical lung resections with that of three other techniques: monopolar electrocautery; neodymium-doped yttrium aluminium garnet laser and harmonic technology. We hypothesized that the thermal damage with harmonic technology could be reduced because of the lower temperatures generated by harmonic technology compared with that of other devices.OBJECTIVES We compared the efficacy of non-anatomical lung resections with that of three other techniques: monopolar electrocautery; neodymium-doped yttrium aluminium garnet laser and harmonic technology. We hypothesized that the thermal damage with harmonic technology could be reduced because of the lower temperatures generated by harmonic technology compared with that of other devices. METHODS Initial studies were performed in 13 isolated pig lungs for each group. A 1.5-cm capsule was inserted within the lung to mimic a tumour and a total of 25 non-anatomical resections were performed with each device. The damage of the resected lung surface and of the tumour border were evaluated according to the colour (ranging from 0 - pink colour to 4 - black colour), histological (ranging from Score 0 - no changes to Score 3 - presence of necrotic tissue) and radiological (ranging from Score 0 - isointense T2 signal at magnetic resonance imaging to Score 3 - hyperintense T2 signal) criteria. A total of seven non-anatomical resections with harmonic technology were also performed in two live pigs to assess if ex vivo results could be reproducible in live pigs with particular attention to haemostatic and air-tightness properties. RESULTS In the ex vivo lung, there was a statistical significant difference between depth of thermal damage (P < 0.0001) in electrocautery (1.3 [1.2-1.4]), laser (0.9 [0.6-0.9]) and harmonic (0.4 [0.3-0.5]) groups. Electrocautery had a higher depth of thermal damage compared with that of the laser (P = 0.01) and harmonic groups (P = 0.0005). The harmonic group had a less depth of thermal damage than that of the laser group (P = 0.01). Also, histological damages of tumour borders (P < 0.001) and resected lung surface (P < 0.001), radiological damage of tumour borders (P < 0.001) and resected lung surface (P < 0.001) and colour changes (P < 0.001) were statistically different between three study groups. Resections of in vivo pig lungs showed no bleeding; 2 of 7 cases of low air leaks were found; however, they ceased by sealing lung parenchyma with harmonic technology. CONCLUSIONS Our experimental data support the resections performed with the use of harmonic technology. The lack of severe tissue alterations could favour healing of parenchyma, assure air tightness and preserve functional lung parenchyma. However, randomized controlled studies are needed in an in vivo model to corroborate our findings

A longitudinal study on BIO14.6 hamsters with dilated cardiomyopathy: micro-echocardiographic evaluation

<p>Abstract</p> <p>Background</p> <p>In recent years, several new technologies for small-animal imaging have been developed. In particular, the use of ultrasound in animal imaging has focused on the investigation of accessible biological structures such as the heart, of which it provides a morphological and functional assessment. The purpose of this study was to investigate the role of micro-ultrasonography (μ-US) in a longitudinal study on BIO14.6 cardiomyopathic hamsters treated with gene therapy.</p> <p>Methods</p> <p>Thirty hamsters were divided into three groups (n = 10): Group I, untreated BIO 14.6 hamsters; Group II, BIO 14.6 hamsters treated with gene therapy; Group III, untreated wild type (WT) hamsters. All hamsters underwent serial μ-US sessions and were sacrificed at predetermined time points.</p> <p>Results</p> <p>μ-US revealed: in Group I, progressive dilation of the left ventricle with a change in heart morphology from an elliptical to a more spherical shape, altered configuration of the mitral valve and subvalvular apparatus, and severe reduction in ejection fraction; in Group II, mild decrease in contractile function and ejection fraction; in Group III, normal cardiac chamber morphology and function. There was a negative correlation between the percentage of fibrosis observed at histology and the ejection fraction obtained on μ-echocardiography (Spearman r: -0.839; p < 0.001).</p> <p>Conclusions</p> <p>Although histological examination remains indispensable for a conclusive diagnosis, high-frequency μ-echocardiography, thanks to the high spatial and contrast resolution, can be considered sufficient for monitoring therapeutic efficacy and/or the progression of dilated cardiomyopathy, providing an alternative tool for repeatable and noninvasive evaluation.</p

Bone fractures difficult to recognize in emergency: May be cone beam computed tomography (CBCT) the solution?

CBCT is an imaging tool represented by an X-ray computed tomography delivering a conic-shape X-rays source. This system produces volumetric data during a single rotation of both X-ray beam and detector around the stationary patient. CBCT is able to produce three-dimensional images as for MDCT, however, accounting some advantages over it: lower radiation dose, faster volumetric dataset acquisition, higher spatial resolution and bone contrast. For these reasons, CBCT has recently been described and adopted for extremities imaging in orthopedics. Misinterpretation of fractures may determine a delayed treatment and poor outcome for patients treated in the ED. CBCT, by easily identifying occult cortical fractures and using a lower dose of radiation, is proposed as an alternative or supplement to direct radiograms, optimizing the cost-effectiveness ratio and limiting the number of unnecessary immobilizations. The first experiences document excellent performance of CBCT in emergency radiology departments, especially thanks to transverse imaging in trauma of the extremities

High resolution real time ultrasonography of the sural nerve after percutaneous repair of the Achilles tendon

Background: Percutaneous Achilles tendon repair has been developed to minimise soft tissue complications following treatment of tendon ruptures. However, there are concerns because of the risk of sural nerve injury. Few studies have investigated the relationship between the Achilles tendon, the sural nerve and its several anatomical course variants.Methods: We studied 7 cadaveric limbs (7 Achilles tendons) in which a percutaneous repair of the Achilles tendon was performed. On each tendon, high resolution real time ultrasonography examination was performed by an experienced musculoskeletal radiologist before and after the procedure, with the surgeons blind to the results of the scan both before and after surgery.Results: In two instances, high resolution real time ultrasonography examination revealed nerve entrapment at the level of most proximal lateral suture.Conclusions: Since the sural nerve can be easily visualised using high-frequency high resolution real time ultrasonography, intraoperative ultrasound can be of assistance during percutaneous repair of Achilles tendon rupture. (C) 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved

Trauma Imaging of the Acute Cervical Spine

Among patients admitted in emergency departments for acute cervical spine trauma, only a few have a confirmed and significant injury requiring surgical intervention. Imaging plays a key role in screening for unstable lesions that can be responsible for devastating neurologic complications or death. The complex anatomy of the cervical spine is associated with a wide spectrum of osseous and ligamentous pathologies. This review focuses on the imaging features of the main cervical spine fractures that can be encountered in emergency radiology

Ultra-High-Frequency Ultrasound: A Modern Diagnostic Technique for Studying Melanoma

The development of new ultra-high-frequency devices with a resolution of 30 mu m makes it possible to use ultrasound in the study of new small anatomical units and to apply this tool to new fields of pathology. Cutaneous melanoma is a severe skin disease with an incidence of approximately 160 000 new cases each year and 48 000 deaths. In this paper, we evaluate the role of HFUS in the diagnosis of cutaneous melanoma, describe the sonographic appearance of skin layers in the pre-excision phase as well as of lesion features, and correlate the characteristics with pathological examination