Functional and molecular 3D mapping of angiosarcoma tumor using non-invasive laser speckle, hyperspectral, and photoacoustic imaging.

Purpose: The gold standard for skin cancer diagnosis is surgical excisional biopsy and histopathological examination. Several non-invasive diagnostic techniques exist, although they have not yet translated into clinical use. This is a proof-of-concept study to assess the possibility of imaging an angiosarcoma in the periocular area.

Comparison of perimetric 24-2 and 30-2 test patterns in detecting visual field defects in patients with tumours in the pituitary region.

Purpose: Automated perimetry provides a standardized method of measuring the visual field. The Humphrey Field Analyser (HFA) uses the 24-2 test pattern to cover 24 degrees centrally or the 30-2 test pattern to cover a slightly broader region of 30 degrees. The aim of this study was to determine whether the 24-2 test pattern provides comparable information to the 30-2 test pattern in detecting visual field defects in patients with tumours in the pituitary region.

Intraoperative visualisation of pancreatic leakage (ViP): study protocol for an IDEAL Stage I Post Market Clinical Study.

Introduction: Pancreatic resections are an important field of surgery worldwide to treat a variety of benign and malignant diseases. Postoperative pancreatic fistula (POPF) remains a frequent and critical complication after partial pancreatectomy and affects up to 50% of patients. POPF increases mortality, prolongs the postoperative hospital stay and is associated with a significant economic burden.

Photoacoustic imaging of periorbital skin cancer : unique spectral signatures of malignant melanoma, basal, and squamous cell carcinoma.

Radical excision of periorbital skin tumors is difficult without sacrificing excessive healthy tissue. Photoacoustic (PA) imaging is an emerging non-invasive biomedical imagi--ng modality that has potential for intraoperative micrographic control of surgical margins. This is the first study to assess the feasibility of PA imaging for the detection of periocular skin cancer.

SmartPAN: In vitro and in vivo proof-of-safety assessments for an intra-operative predictive indicator of postoperative pancreatic fistula.

Pancreatic surgery is complicated by untreated fluid leakage, but no tenable techniques exist to detect and close leakage sites during surgery. A novel hydrogel called SmartPAN has been developed to meet this need and is here assessed for safety before trials on human patients. First, resazurin assays were used to test the cytotoxic effects of SmartPAN's active bromothymol blue (BTB) indicator and its solution of phosphate-buffered saline (PBS) on normal (HPDE: human pancreatic duct epithelial) or carcinomic (FAMPAC) human pancreatic cells.

Comparison of photoacoustic imaging and histopathological examination in determining the dimensions of 52 human melanomas and nevi .

Surgical excision followed by histopathological examination is the gold standard for the diagnosis and staging of melanoma. Reoperations and unnecessary removal of healthy tissue could be reduced if non-invasive imaging techniques were available for presurgical tumor delineation. However, no technique has gained widespread clinical use to date due to shallow imaging depth or the absence of functional imaging capability.

Photoacoustic imaging for the monitoring of local changes in oxygen saturation following an adrenaline injection in human forearm skin.

Clinical monitoring of blood oxygen saturation (sO) is traditionally performed using optical techniques, such as pulse oximetry and diffuse reflectance spectroscopy (DRS), which lack spatial resolution. Photoacoustic imaging (PAI) is a rapidly developing biomedical imaging technique that is superior to previous techniques in that it combines optical excitation and acoustic detection, providing a map of chromophore distribution in the tissue. Hitherto, PAI has primarily been used in preclinical studies, and only a few studies have been performed in patients.

Photoacoustic imaging for non-invasive examination of the healthy temporal artery - systematic evaluation of visual function in healthy subjects.

Purpose: Photoacoustic (PA) imaging has the potential to become a non-invasive diagnostic tool for giant cell arteritis, as shown in pilot experiments on seven patients undergoing surgery. Here, we present a detailed evaluation of the safety regarding visual function and patient tolerability in healthy subjects, and define the spectral signature in the healthy temporal artery.

Methods: Photoacoustic scanning of the temporal artery was performed in 12 healthy subjects using 59 wavelengths (from 680 nm to 970 nm).

Photoacoustic imaging for three-dimensional visualization and delineation of basal cell carcinoma in patients.

Background: Photoacoustic (PA) imaging is an emerging non-invasive biomedical imaging modality that could potentially be used to determine the borders of basal cell carcinomas (BCC) preoperatively in order to reduce the need for repeated surgery.

Methods: Two- and three-dimensional PA images were obtained by scanning BCCs using 59 wavelengths in the range 680-970 nm. Spectral unmixing was performed to visualize the tumor tissue distribution.

Unique spectral signature of human cutaneous squamous cell carcinoma by photoacoustic imaging.

Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with metastatic potential. To reduce reoperations due to nonradical excision, there is a need to develop a technique for identification of tumor margins preoperatively. Photoacoustic (PA) imaging is a novel imaging technology that combines the strengths of laser optics and ultrasound.

Hypoperfusion following the injection of epinephrine in human forearm skin can be measured by RGB analysis but not with laser speckle contrast imaging.

Background: The time taken for epinephrine to achieve its optimal effect during local anesthesia has recently become the subject of debate. The time from injection to commencement of surgery is traditionally quoted to be 7 to 10 min, while recent reports claim that it may take 30 min to achieve maximum hypoperfusion, which would prolong the time required for surgical procedures. The discrepancy may be related to difficulties associated with the techniques used to measure blood perfusion.

Active role of capillary pericytes during stimulation-induced activity and spreading depolarization.

Spreading depolarization is assumed to be the mechanism of migraine with aura, which is accompanied by an initial predominant hyperaemic response followed by persistent vasoconstriction. Cerebral blood flow responses are impaired in patients and in experimental animals after spreading depolarization. Understanding the regulation of cortical blood vessels during and after spreading depolarization could help patients with migraine attacks, but our knowledge of these vascular mechanisms is still incomplete.

Stimulation-induced increases in cerebral blood flow and local capillary vasoconstriction depend on conducted vascular responses.

Functional neuroimaging, such as fMRI, is based on coupling neuronal activity and accompanying changes in cerebral blood flow (CBF) and metabolism. However, the relationship between CBF and events at the level of the penetrating arterioles and capillaries is not well established. Recent findings suggest an active role of capillaries in CBF control, and pericytes on capillaries may be major regulators of CBF and initiators of functional imaging signals.

Activity-dependent calcium, oxygen, and vascular responses in a mouse model of familial hemiplegic migraine type 1.

Objective: Familial hemiplegic migraine type 1 (FHM1) is a subtype of migraine with aura caused by a gain-of-function mutation in the pore-forming α1 subunit of CaV 2.1 (P/Q-type) calcium channels. However, the mechanisms underlying how the disease is brought about and the prolonged aura remain incompletely understood.

Glutamate-system defects behind psychiatric manifestations in a familial hemiplegic migraine type 2 disease-mutation mouse model.

Migraine is a complex brain disorder, and understanding the complexity of this prevalent disease could improve quality of life for millions of people. Familial Hemiplegic Migraine type 2 (FHM2) is a subtype of migraine with aura and co-morbidities like epilepsy/seizures, cognitive impairments and psychiatric manifestations, such as obsessive-compulsive disorder (OCD). FHM2 disease-mutations locate to the ATP1A2 gene encoding the astrocyte-located α2-isoform of the sodium-potassium pump (α2Na(+)/K(+)-ATPase).

Capillary pericytes regulate cerebral blood flow in health and disease.

Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate that neuronal activity and the neurotransmitter glutamate evoke the release of messengers that dilate capillaries by actively relaxing pericytes.

Angiography and multifocal electroretinography show that blood supply to the pig retina may be both ipsilateral and contralateral.

Purpose: We recently presented a transfemoral endovascular coiling technique for inducing experimental retinal ischemia in pigs. Substantial variation was seen in the degree of ischemia. It was hypothesized that the blood supply to the retina may originate from both the ipsilateral and contralateral ophthalmic arteries and that there may be an interconnecting artery between the eyes.

The effects of variable, intermittent, and continuous negative pressure wound therapy, using foam or gauze, on wound contraction, granulation tissue formation, and ingrowth into the wound filler.

Objective: Negative pressure wound therapy (NPWT) is commonly used in the continuous mode. Intermittent pressure therapy (IPT) results in faster wound healing, but it often causes pain. Variable pressure therapy (VPT) has therefore been introduced to provide a smooth transition between 2 different pressure environments, thereby maintaining the negative pressure environment throughout the therapy.

Endovascular coiling of the ophthalmic artery in pigs to induce retinal ischemia.

Purpose: The authors recently showed that the retinal circulation can be accessed by transfemoral endovascular catheterization. The purpose of this study was to examine whether endovascular coiling can be used to induce different degrees of ischemic injury. The possibility of creating occlusions at different sites in the vasculature to cause retinal ischemia with different degrees of severity was investigated.

Tumor necrosis factor and its receptors in the neuroretina and retinal vasculature after ischemia-reperfusion injury in the pig retina.

Purpose: Numerous studies have been performed aimed at limiting the extent of retinal injury after ischemia, but there is still no effective pharmacological treatment available. The aim of the present study was to examine the role of tumor necrosis factor (TNF)α and its receptors (TNF-R1 and TNF-R2), especially considering the neuroretina and the retinal vasculature since the retinal blood vessels are key organs in circulatory failure.

Methods: Retinal ischemia was induced in pigs by elevating the intraocular pressure to 80 mmHg in one eye, while the other eye served as a control (sham-operated).

Hypoxia-inducible factor and vascular endothelial growth factor in the neuroretina and retinal blood vessels after retinal ischemia.

Retinal ischemia arises from circulatory failure. As the retinal blood vessels are key organs in circulatory failure, our aim was to study the retinal vasculature separately from the neuroretina to elucidate the role of hypoxia-inducible factor (HIF) 1α and 1β and vascular endothelial growth factor (VEGF) in retinal ischemia. Retinal ischemia was induced in porcine eyes by applying an intraocular pressure, followed by 12 h of reperfusion.

Mitogen-activated protein kinases in the porcine retinal arteries and neuroretina following retinal ischemia-reperfusion.

Purpose: The aim of the present study was to examine changes in the expression of intracellular signal-transduction pathways, specifically mitogen-activated protein kinases, following retinal ischemia-reperfusion.

Methods: Retinal ischemia was induced by elevating the intraocular pressure in porcine eyes, followed by 5, 12, or 20 h of reperfusion. The results were compared to those of the sham- operated fellow eye.

Multifocal electroretinogram for functional evaluation of retinal injury following ischemia-reperfusion in pigs.

Background: Multifocal electroretinogram (mfERG) has the power to discriminate between localized functional losses and overall retinal changes when evaluating retinal injury. So far, full-field ERG has been the gold standard for examining retinal ischemia and the effects of different neuroprotectants in experimental conditions. The aim of the present study was to establish mfERG, with simultaneous fundus monitoring, for analyzing the localized functional response in the retina after ischemia-reperfusion in the porcine eye.

The porcine retinal vasculature accessed using an endovascular approach: a new experimental model for retinal ischemia.

Purpose: The aim of this study was to examine whether the retinal circulation in the pig can be accessed using interventional neuroradiology and to explore the possibility of creating occlusions that result in experimental retinal ischemia.

Methods: Six experiments were performed using 100-kg pigs. The external carotid system was catheterized using a fluoroscopy-monitored, transfemoral, endovascular approach.