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PubMed2001

Visualizing excitation waves inside cardiac muscle using transillumination.

Voltage-sensitive fluorescent dyes have become powerful tools for the visualization of excitation propagation in the heart. However, until recently they were used exclusively for surface recordings. Here we demonstrate the possibility of visualizing the electrical activity from inside cardiac muscle via fluorescence measurements in the transillumination mode (in which the light source and photodetector are on opposite sides of the preparation). This mode enables the detection of light escaping from layers deep within the tissue. Experiments were conducted in perfused (8 mm thick) slabs of sheep right ventricular wall stained with the voltage-sensitive dye di-4-ANEPPS. Although the amplitude and signal-to-noise ratio recorded in the transillumination mode were significantly smaller than those recorded in the epi-illumination mode, they were sufficient to reliably determine the activation sequence. Penetration depths (spatial decay constants) derived from measurements of light attenuation in cardiac muscle were 0.8 mm for excitation (520 +/- 30 nm) and 1.3 mm for emission wavelengths (640 +/- 50 nm). Estimates of emitted fluorescence based on these attenuation values in 8-mm-thick tissue suggest that 90% of the transillumination signal originates from a 4-mm-thick layer near the illuminated surface. A 69% fraction of the recorded signal originates from > or =1 mm below the surface. Transillumination recordings may be combined with endocardial and epicardial surface recordings to obtain information about three-dimensional propagation in the thickness of the myocardial wall. We show an example in which transillumination reveals an intramural reentry, undetectable in surface recordings.

Animals↗
PubMed1999

Plaque-mounted diode-light transillumination for localization around intraocular tumors.

OBJECTIVE: To evaluate the usefulness of plaque-mounted diode-light transillumination (DLT) for the localization of episcleral plaques around intraocular tumors. METHODS: A clinical case series was performed to create, evaluate, and modify diode-light plaque construction, application, and imaging. Eight patients with choroidal melanoma were offered DLT as an additional method of ophthalmic plaque localization. Plaques were constructed by affixing non-heat-producing, light-emitting diodes with their apertures flush with the episcleral outer surface of the rim of the plaque. A bioimplantable epoxy was used to encapsulate the electronic components. Radioactive DLT eye plaques were sewn to the episclera to cover the base of the intraocular tumors; then diode lights were illuminated, viewed, and recorded. Thus, DLT was used to photographically document the relative position of the eye plaque covering the tumor base. The use of DLT also permitted a subjective evaluation of the contact (plaque contact) of each light with the sclera. RESULTS: Still and video images of plaque-mounted diode retro-transillumination were obtained, and no evidence of toxic effects of diode light were noted. CONCLUSIONS: Small posterior melanomas are difficult to visualize with standard transillumination techniques and are associated with poor local control. To improve and document plaque placement, we developed plaque-mounted diode lights for retrobulbar transillumination. This technique provides unique photographic documentation of episcleral plaque localization beneath intraocular tumors.

Brachytherapy↗
PubMed2006

The endoscopic transilluminator: an endoscopic device for identification of the proximal jejunum for transgastric endoscopic gastrojejunostomy.

BACKGROUND: Localization of the proximal jejunum is important for creation of gastrojejunal anastomosis to palliate gastric outlet obstruction or for treatment of obesity with gastric bypass. OBJECTIVE: To facilitate identification of the proximal jejunum during transgastric endoscopic gastrojejunostomy with the use of an endoscopic transilluminator (ET). DESIGN AND SETTING: Acute experiments in a live porcine model. INTERVENTIONS: The ET is a 3500-mm long, 6F radio-opaque tube with a fiberoptic core that lights up at its distal end. When situated in the intestinal lumen, it transilluminates the bowel wall. With the animal under general anesthesia with endotracheal intubation, a colonoscope was advanced to the proximal jejunum. A plastic tube (3500-mm long, 3.5 mm in diameter) was passed through the biopsy channel and placed into the small bowel. The colonoscope was withdrawn, leaving the tube in place. The ET was introduced into the jejunum through the tube. A gastric wall incision was made and the endoscope was advanced to the peritoneal cavity. The transilluminated loop of the proximal jejunum was identified and gastrojejunal anastomosis was made by use of a previously reported endoscopic technique. MAIN OUTCOME MEASUREMENTS: Identification of the proximal jejunum. RESULTS: Eleven pigs (average weight 55 kg) had ET placement. In all of the pigs, placement of the ET was performed easily to the proximal small bowel, and the proximal jejunum was successfully localized by either direct visualization of the transilluminated loop only or with the aid of fluoroscopy. The tip of the ET was usually located about 50 to 70 cm distal to the ligament of Treitz. There were no complications related to the use of ET. LIMITATIONS: The device has not yet been evaluated in humans. CONCLUSIONS: The ET is a safe instrument and can be used to identify the proximal jejunum to facilitate endoscopic gastrojejunostomy.

Animals↗
PubMed1999

Diode-light transillumination for ophthalmic plaque localization around juxtapapillary choroidal melanomas.

PURPOSE: An evaluation of plaque-mounted diode-light transillumination (DLT) for localization of episcleral plaques beneath juxtapapillary tumors. METHODS AND MATERIALS: Two patients scheduled for radiotherapy for juxtapapillary melanomas were offered DLT as an additional method of ophthalmic plaque localization. Plaques were constructed by affixing 4 non-heat producing, light-emitting diodes with their apertures flush with the episcleral outer surface of the plaque's rim. Bio-implantable epoxy was used to encapsulate the electronic components. Then the plaques were loaded with 103Pd seeds. After the eye-plaques were sewn to the episclera covering the base of the intraocular tumors; the diode-lights were illuminated, viewed and recorded. Photodocumentation of the relative position of the 4 lights around tumor's base was obtained in both cases. RESULTS: Digital images of plaque-mounted diode retro-transillumination were obtained. No evidence of diode-light toxicity was noted. Both tumors were found to be covered by the ophthalmic plaques. CONCLUSION: Juxtapapillary tumors are often difficult or impossible to visualize with standard transillumination techniques and have been associated with poor local control rates. We have developed plaque-mounted DLT in an effort to improve ophthalmic plaque localization. Retrobulbar transillumination was viewed by indirect ophthalmoscopy and recorded with video-imaging. This technique provides unique photographic documentation of episcleral plaque localization beneath juxtapapillary tumors.

Choroid Neoplasms↗
PubMed1996

Laparoscopic transillumination for the location of anterior abdominal wall blood vessels.

OBJECTIVE: To determine the efficacy of transillumination for locating abdominal wall vessels prior to trocar placement during laparoscopy. DESIGN: Prospective clinical descriptive study. SETTING: Normal human volunteers in an academic research environment. PATIENTS: Forty-seven white and 21 black women of various weights undergoing laparoscopy for clinical indications unrelated to this study. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The location and number of abdominal wall vessels visible by transillumination were recorded for each patient. RESULTS: In women of normal weight, a single vessel could be seen approximately 5 cm from the midline in > 90% of the patients, and second vessel approximately 8 cm from the midline could also be seen in 51%. The more medial vessels did not correlate with the course of the inferior epigastric vessels seen laparoscopically. The ability to see vessels was decreased significantly by the patients' weight but not by skin color. CONCLUSIONS: Superficial abdominal wall vessels may be located by transillumination in the majority of women of normal weight regardless of skin color, but is of less value in overweight and obese women. However, the deep (inferior) epigastric vessels cannot be effectively located by transillumination, and thus other techniques should be used to minimize the risk of injury to these vessels.

Abdominal Muscles↗
PubMed1996

Transillumination of iris and subnormal visual acuity--ocular albinism?

BACKGROUND: A common clinical sign in children with subnormal visual acuity or slow visual development was iris transillumination. This was used as the inclusion criterion in a study of children shown to have a subnormal visual acuity in a general health examination at age 4 years. METHODS: Refraction values, stereopsis, fundus photography, macular and nerve head appearance, and visual evoked response (VER) recordings were studied in 18 children. The clinical results were compared with 64 controls referred to the eye clinic because of subnormal vision from the general health examination or from school health care. RESULTS: Eight children had VERs showing asymmetry typical for albinism. Another four had only small asymmetries on the VER, indicating a lower degree of decussation abnormality. No simple correlation of visual acuity, degree of iris transillumination, stereopsis, or macular pathology and VER asymmetries were found. However, marked iris transillumination in all four quadrants, absence of a foveal reflex, and low visual acuity were weakly correlated. CONCLUSIONS: In a rather homogeneous group of children with iris transillumination and subnormal visual acuity eight of 18 had typical albino VERs. The findings of small atypical VER asymmetries in four children and no asymmetry in six children suggest that albinism may be considered as a description of a heterogeneous group of conditions including maximal decussation rate (100%) in the chiasma to a condition with almost normal (> or = 50%) decussation rate.

Adolescent↗
PubMed2000

The real performance of bitewing radiography and fiber-optic transillumination in approximal caries diagnosis.

For both general practitioners and researchers in caries diagnostics, the true validity of available diagnostic techniques is of considerable interest. Yet, for both bitewing radiography and fiber-optic transillumination, this is still not accurately known, nor is it clear which of the two techniques performs best clinically. This study's purpose was to estimate the clinical performance of the two techniques in diagnosing approximal caries lesions in low-caries-prevalence populations. Clinical studies that compare the two techniques were selected from literature. We determined 2 x 2 contingency tables from these studies and calculated one overall contingency table. The cut-off for decay was at dentinal caries. Assuming that erroneous outcomes from both techniques are mutually independent, we expressed diagnostic sensitivity and specificity of the two techniques as functions of the contingency table cell contents, with caries prevalence as the parameter. Because the caries prevalence was unknown, every sensitivity and specificity value was possible. From the conditions that sensitivity, specificity, and caries prevalence are always between one and zero, a limited range of sensitivity and specificity values was obtained. Three situations were examined: Bitewing radiography specificity is 1, fiber-optic transillumination specificity is 1, and both specificities are equal. Under these conditions, the bitewing radiography sensitivity was between 1.00 and 0.71 +/- 0.01, and the fiber-optic transillumination sensitivity was between 0.70 +/- 0.01 and 0.50 +/- 0.02. Both specificities were between 1.00 and 0.99. We concluded that the two techniques have comparable specificities. but that the fiber-optic transillumination sensitivity is significantly lower than that for bitewing radiography.

Dental Caries↗
PubMedDate not supplied

Analysis of methods to assess frontal sinus extent in osteoplastic flap surgery: transillumination versus 6-ft Caldwell versus image guidance.

BACKGROUND: The aim of this study was to compare three common methods (transillumination, plain radiographs, and computerized tomography [CT] image guidance) for estimating the position and extent of pneumatization of the frontal sinus in osteoplastic flap surgery. METHODS: Axial CT scans and 6-ft Caldwell radiographs were performed on 10 cadaver heads. For each head, soft tissue overlying the frontal bone was raised and the anticipated position and extent of the frontal sinus at four points was marked using three common methods. The silhouette of the frontal sinus from the Caldwell plain radiograph was excised and placed in position. Four points at the periphery also were made using information obtained from a passive optically guided image-guided surgery device, and transillumination via a frontal trephination also was used to estimate sinus extent. The true sinus size was measured at each point and compared with experimental values. RESULTS: The use of CT image guidance generated the least difference between measured and actual values (mean = 1.91 mm; SEM = 0.29); this method was found statistically superior to Caldwell (p = 0.040) and transillumination (p = 0.007). Image guidance did not overestimate the size of the sinus (0/36) and was quicker than the Caldwell approach (8.5 versus 11.5 minutes). There was no learning curve appreciated with image guidance. CONCLUSION: Accurate and precise estimation of the position and extent of the frontal sinus is crucial when performing osteoplastic flap surgery. Use of CT image guidance was statistically superior to Caldwell and transillumination methods and proved to be safe, reproducible, economic, and easy to learn.

Cadaver↗
PubMed1987

Transillumination in bite mark evidence.

Transillumination of bite mark evidence is a technique whereby the presence of subcutaneous hemorrhage can be visualized without having to section through the bite mark. This is a nondestructive technique. The presence of subcutaneous hemorrhage indicates that the bite mark was inflicted before death or perimortem. In addition, the technique proves invaluable in determining the orientation of the bite mark. This is particularly helpful when a bite mark is poorly defined, barely visible, or obscured by other superimposed bite marks or traumatic injury patterns. Observation of the subcutaneous hemorrhage by transillumination may provide an indication of the horizontal alignment of the aggressor's dentition since the force of occlusion used in delivery of the bite mark is a factor in the presence and intensity of the hemorrhage. Transillumination supports a conclusion that there may be two types of hemorrhagic patterns in bite mark evidence. Lastly, when transillumination is used in conjunction with visual aids, it can facilitate communication of bite mark evidence to other expert witnesses or to the jury in trial presentation or both.

Bites and Stings↗
PubMed1998

Segmental denervation and reinnervation of the iris sphincter as shown by infrared videographic transillumination.

OBJECTIVE: This study aimed to analyze the denervation and reinnervation history of individual segments of the iris sphincter in patients with Adie's syndrome. DESIGN: The irises of these patients were retroilluminated by shining an infrared-rich light through the lower eyelid and sclera and viewing the transilluminated iris from the front with an infrared-sensitive video camera. The irises of the same group of patients also were videotaped through a slit-lamp camera using routine frontal illumination. Both of these techniques also were used to examine a series of normal subjects. PARTICIPANTS: A total of 61 patients with Adie's syndrome or Adie's-like denervation of the iris sphincter (from surgery, trauma, or radiation) and 10 normal subjects were studied. MAIN OUTCOME MEASURES: Slit-lamp examination results of the segmental movement of the iris were compared to the infrared transillumination pattern of the iris sphincter before and during the light reflex, before and during the near-vision reaction, before and during eye movement, and before and after the application of dilute pilocarpine and 1% pilocarpine. RESULTS: Whenever an iris sphincter segment contracted, it also became denser by using these techniques. Reinnervated iris segments failed to contract to light but did contract and became denser with a near effort or with eye movement. Segments supersensitive to pilocarpine became denser than adjacent segments without supersensitivity, but atrophic-appearing segments looked translucent and thin, failing to become denser, even with 1% pilocarpine. CONCLUSIONS: The innervational history and current status of each clock-hour segment of the iris sphincter can be determined using this technique of videographic infrared transillumination, and the progression and pattern of iris denervation and reinnervation can be determined in patients with Adie's pupil. A miotic Adie's pupil that is "tonic," even in darkness, was found to be associated with a dense pattern of infrared transillumination in sphincter segments, which the authors interpret as being associated with a rich reinnervation from accommodative fibers. Segments that become densely reinnervated appear to lose their cholinergic supersensitivity.

Adie Syndrome↗
PubMedDate not supplied

Use of light absorbers to alter optical interrogation with epi-illumination and transillumination in three-dimensional cardiac models.

Cardiac optical mapping currently provides 2-D maps of transmembrane voltage-sensitive fluorescence localized near the tissue surface. Methods for interrogation at different depths are required for studies of arrhythmias and the effects of defibrillation shocks in 3-D cardiac tissue. We model the effects of coloading with a dye that absorbs excitation or fluorescence light on the radius and depth of the interrogated region with specific illumination and collection techniques. Results indicate radii and depths of interrogation are larger for transillumination versus epi-illumination, an effect that is more pronounced for broad-field excitation versus laser scanner. Coloading with a fluorescence absorber lessens interrogated depth for epi-illumination and increases it for transillumination, which is confirmed with measurements using transillumination of heart tissue slices. Coloading with an absorber of excitation light consistently decreases the interrogated depths. Transillumination and coloading also decrease the intensities of collected fluorescence. Thus, localization can be modified with wavelength-specific absorbers at the expense of a reduction in fluorescence intensity.

Animals↗
PubMed1989

The diagnostic value of transillumination for maxillary sinusitis in children.

In 52 children between 3 and 9 years of age drainage of the maxillary sinus was performed because of chronic purulent rhinitis and opacity of the maxillary sinuses on the radiographs. The results of preoperative transillumination were compared with the drainage findings. In this selected group of children the sensitivity of transillumination for the demonstration of congestion in the maxillary sinuses was found to be limited. The authors consider transillumination to be an obsolete method for this purpose in children.

Child↗
PubMed1987

Bond strengths of lingual orthodontic brackets bonded with light-cured composite resins cured by transillumination.

A method of curing light-cured composite resins by transillumination to cement acid-etched fixed partial dentures was adapted to bond solid mesh-backed lingual orthodontic brackets. Results of this investigation showed that the bond strengths of the orthodontic brackets bonded with light-cured composite resins were significantly less (P less than 0.05) than the bond strengths of the orthodontic brackets cemented with traditional adhesives and orthodontic composite resins. Notwithstanding, the bond strengths achieved with the transilluminated light-cured composite resins should be adequate to withstand the forces of mastication and orthodontic movements. There was no correlation of bond strengths of the brackets cemented with the transilluminated light-cured composite resins when compared to the faciolingual widths of the teeth.

Acrylic Resins↗
PubMed1977

Cranial transillumination norms of the premature infant.

Ninety-five infants from 26 to 42 weeks of gestational age were studied with a simple standardized cerebral transillumination technique utilizing a Chun gun fitted with a clear flexible disc to establish normal measurements and to test the hypothesis that transillumination is useful in differentiating "catch-up" growth from hydrocephalus. One group of infants were measured at birth; the other group were infants grown to similar gestational age and serially measured. Data from these groups were found to be similar. Transillumination was not found to be a useful technique for separating "catch-up" growth infants from the normal population, but was found to be potentially useful in separating the normal and "catch-up" population from children with hydrocephalus or serious anatomic abnormalities of the central nervous system.

Brain↗
PubMed1984

Iris transillumination defect and microhyphema syndrome.

We present a previously undescribed delayed complication attributable to sulcus-fixated posterior chamber lenses with elliptical polypropylene haptics containing a 10 degrees anterior angulation. Clinical signs of this complication are crescent-shaped iris transillumination defects overlying the lens haptics in the peripheral iris; in some cases these are associated with single or recurrent visually significant microhyphemas. This series describes 41 eyes that contain these transillumination defects; eight of the eyes have had lens-induced intraocular hemorrhage. We estimate the overall incidence of transillumination defects in our sulcus-fixated posterior chamber lens patient population to be between 5% and 15%. Those patients who have had lens-induced hemorrhage represent slightly greater than 1%, which is higher than our incidence of cystoid macular edema or retinal detachment. It is important for all ophthalmologists to be aware of this syndrome in evaluating patients with posterior chamber lenses who present with a transient obscuration of vision.

Aged↗
PubMed1996

[CT-guided percutaneous endoscopic gastrostomy: a successful method if transillumination is not possible].

BACKGROUND AND OBJECTIVE: If transillumination is not possible, percutaneous endoscopic gastrostomy (PEG) is contraindicated. In these cases the stomach had so far to be punctured directly during radiological monitoring. A new method is described which combines endoscopy and computed tomography (CT) for performing a percutaneous endoscopic gastrostomy. PATIENTS AND METHODS: Among 189 patients who were to have the procedure there were eleven (nine men, two women) in whom transillumination was not possible. After endoscopic insufflation of air PEG was done under CT guidance, using the common pull-through technique. RESULTS: The combined method was successful in ten of the eleven patients without complication. In one patient with hepatomegaly and interposition of the transverse colon PEG was not possible even with CT guidance. CONCLUSIONS: The combined endoscopic-radiological method is practicable and safe in cases in which transillumination is not possible. There are several advantages compared with direct puncturing: The common pull-through technique can be used; radiological exposure is low and other clinically relevant findings may be revealed by the endoscopy.

Adult↗
PubMed2000

Low-level laser therapy for wound healing: feasibility of wound dressing transillumination.

OBJECTIVE: The purpose of this study was to assess the feasibility of exposing wounds during low-level laser therapy (LLLT) by transillumination of the wound dressings. BACKGROUND DATA: LLLT has been associated with accelerated wound healing in chronic ulcers. The usual approach is to remove wound dressings prior to exposure and to treat three to five times weekly. Frequent change of wound dressings is time consuming and costly; it disrupts the healing process, increases the risk of wound infection, and may be traumatic for the patient. METHODS: A double integrating sphere setup was employed to quantify the diffuse transmittance and reflectance of various wound dressings. Differences in transmittance for large area sources and point sources were demonstrated through the use of a diode laser and an incoherent light source. RESULTS: There were a number of gels and membrane style wound dressings with diffuse transmittance of more than 50%. Hence, for these dressings the prescribed radiant exposure to the wound surface could be achieved by increasing the exposure duration, while maintaining reasonable overall treatment times. CONCLUSIONS: Although LLLT by transillumination of wound dressings is feasible for a variety of wound dressings without significant commitments in additional treatment time, the specific transmission of products not included in this study needs to be determined at the intended treatment wavelength. A transillumination approach may facilitate a faster rate of wound healing than LLLT applied to exposed wounds by reducing trauma and the risk of infection.

Absorption↗
PubMed2000

Ultraviolet light hazards from transilluminators.

Ultraviolet (UV) light boxes ("transilluminators") are commonly used in molecular biology laboratories for visualizing ethidium bromide-intercalated nucleic acids separated under electric current in electrophoretic gels. These devices typically have peak outputs at 254 or 312 nm, well within the UV-C and -B regions that are biologically active and capable of damaging skin. Field evaluations of laboratory transilluminators under actual conditions of use indicate that the UV light emitted from transilluminators is an identifiable and potentially significant occupational hazard for many laboratory workers, as is the high frequency of workstation surface contamination with ethidium bromide, a known mutagen. Fortunately, these hazards can be relatively easily controlled through worker training and the regular use of basic personal protective equipment.

Equipment Failure↗