Intra-Arterial Verapamil Treatment in Oral Therapy-Refractory Reversible Cerebral Vasoconstriction Syndrome

Reversible vasoconstriction syndrome is a complex of clinical symptoms and angiographic findings, which, while having a mostly benign clinical course, has clinical and imaging overlap with more serious disorders such as vasculitis and aneurysmal SAH and itself includes a minority of patients with fulminant vasoconstriction resulting in severe intracranial complications. Endovascular options for patients with refractory reversible cerebral vasoconstriction syndrome include intra-arterial vasodilator infusion similar to therapy for patients with vasospasm after SAH. To date, only case reports and 1 small series have discussed the utility of intra-arterial vasodilators for the treatment of reversible cerebral vasoconstriction syndrome. We report an additional series of 11 medically refractory cases of presumed or proved reversible cerebral vasoconstriction syndrome successfully treated with intra-arterial verapamil infusion. Furthermore, we propose that the reversal of vasoconstriction, as seen on angiography, could fulfill a diagnostic criterion.

Digital integrated retinal surgical laser system

The year is 2001--ophthalmic retinal surgery is now fully computer assisted. Patients arriving for scheduled treatments of diabetic retinopathy, retinal tears, or macular degeneration have their retina digitally mapped by a technician. From the retinal map, the ophthalmologist plots therapeutic lesion sites with a light pen on the computer screen that will automatically be placed by a computer controlled argon laser. The treatment only requires 100 ms per lesion placement thus reducing office calls to approximately 45 minutes freeing the ophthalmologist for other pressing cases. This paper reports on the development of a clinically significant prototype system that will help bring this scenario to fruition.

Hybrid retinal photocoagulation system using analog tracking

We describe initial in vivo experimental results of a new hybrid digital and analog design for retinal tracking and laser beam control. An overview of the design is given. The results show in vivo tracking rates which exceed the equivalent of 38 degrees per second in the eye, with automated lesion pattern creation. Robotically-assisted laser surgery to treat conditions such as diabetic retinopathy and retinal breaks may soon be realized under clinical conditions with requisite safety using standard video hardware and inexpensive optical components based on this design.

A method to control irradiation time for laser photocoagulation of the retina--Part II

When performing laser photocoagulation of the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filter and estimation techniques on the sampled reflectance signal, the latency time and growth rate of the lesion reflectance are determined. These parameters are then used to estimate the absorption coefficient of the irradiated tissue. From these estimates, the irradiation time of the laser can be accurately determined so that optimum therapeutic effect may be obtained, without overexposing the tissue. The result is consistent lesion formation over any part of the retina. This paper is a follow up to [4] and provides details of the experimental setup and signals acquisition.

Hybrid tracking system for retinal photocoagulation prototype II

Laser photocoagulation has been employed extensively by ophthalmologists to treat retinal diseases and disorders such as diabetic retinopathy, macular degeneration, and retinal tears. Treatment is a manual task requiring the physician to carefully place therapeutic lesions on the retina while avoiding critical vision anatomy. We have developed a hybrid tracking system using two retinal tracking modalities: a digital imaging-based subsystem and an analog tracking subsystem to stabilize the irradiating laser on the retina. We have also investigated a lesion parameter control subsystem to provide uniform therapeutic lesions.

Determining laser dosimetry for consistent retinal photocoagulation

Laser photocoagulation is used extensively by ophthalmologists to treat retinal disorders such as diabetic retinopathy, macular degeneration, and retinal tears. Currently, the procedure is performed manually and suffers from several drawbacks that a computer-assisted system could help alleviate. These drawbacks include the tedious nature of the procedure for both the patient and the physician and also the extreme criticality of the task. A system is under development that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. This system provides real-time, motion-stabilized lesion placement for typical clinical irradiation times on the order of 100 ms. Considerable work has been accomplished on stabilizing the irradiating laser on the retinal surface. Various tracking systems have been designed, prototypes implemented, and tested in vivo on laboratory animals [1]. Our efforts have most recently concentrated on developing a system to monitor lesion growth in real time and turn off the laser when the desired lesion parameters have been achieved. This subsystem employs dynamic lesion reflectance as an indirect measure of lesion depth. Our goal has been to establish a correlation between the measurable lesion reflectance parameter with the actual lesion depth. Once this correlation is established, these parameters will be used to generate a control signal for the irradiation time of the laser. The goal is to optimize the therapeutic effect, without over- or under-exposing the tissue. The result is consistent lesion formation over any part of the non-homogeneous retinal tissue.

Deriving irradiation control parameters for laser photocoagulation on the retina

Laser photocoagulation is used extensively by ophthalmologists to treat retinal disorders such as diabetic retinopathy and retinal breaks. Currently, the procedure is performed manually and suffers from several drawbacks that a computer-assisted system could help alleviate. Such a system is under development that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. This system provides real-time, motion-stabilized lesion placement for typical clinical irradiation times (100 ms). When performing laser photocoagulation on the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filtering and estimation techniques on the sampled reflectance signal, the latency time and growth rate are determined. These parameters are used to derive a control signal for the irradiation time of the laser. The goal is to optimize the therapeutic effect, without overexposing the tissue. The result is consistent lesion formation over any part of the retina.

Initial in vivo results of a hybrid retinal photocoagulation system

We describe initial in vivo experimental results of a new hybrid digital and analog design for retinal tracking and laser beam control. An overview of the design is given. The results show in vivo tracking rates which exceed the equivalent of 38 degrees/s in the eye. A robotically assisted lesion pattern is created for laser surgery to treat conditions such as diabetic retinopathy and retinal breaks.

Development of an integrated automated retinal surgical laser system

Diabetes is a serious disease that affects millions of people world wide. One of the many complications that may result from this disease is an eye disorder called diabetic retinopathy. This side effect is characterized by the leaching of fluid, mainly blood, into the retinal tissue ultimately killing the rods and cones in the area. Scientists have discovered that by occulating and destroying some of the capillaries near the infected area, further damage may be limited and further vision loss prevented. This procedure is performed on the retina by using a Continuous Wave argon laser to place a pattern of lesions that kill the rods, cones, and underlying capillaries. The "Computer Aided Laser Optics System for Ophthalmic Surgery" or CALOSOS is a system that fully integrates the placement of therapeutic retinal lesions through computer control. To date, two different sub-systems have been used to achieve the desired accuracy needed including lesion placement and depth; an all-digital system and a hybrid analog/digital system. The current tracking system that precisely controls the laser uses a wide-angle lens camera to view the whole retina. The difficulty lies in the fact that the only way to control the depth of the lesion is to measure the central reflectance. The goal of this research is to establish that there is a linear relationship between the reflectance of the lesion and the depth of the lesion when this wide-angle lens is used.

A method to control irradiation time for laser photocoagulation on the retina

When performing laser photocoagulation on the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filter and estimation techniques on the sampled reflectance signal, the latency time and growth rate of the lesion reflectance are determined. These parameters are then used to estimate the absorption coefficient of the illuminated tissue. From these estimates, the irradiation time of the laser can be accurately determined so that optimum therapeutic effect may be obtained, without overexposing the tissue. The result is consistent lesion formation over any part of the retina.

Integration of analog and digital retinal tracking and coagulation subsystems

Laser photocoagulation is used by ophthalmologists to treat retinal disorders such as diabetic retinopathy and retinal breaks and tears. Currently, the procedure is performed manually and suffers from several drawbacks: it often requires many clinical visits, it is very tedious for both patient and physician, the laser pointing accuracy and safety margin are limited by a combination of the physician's manual dexterity and the patient's ability to hold their eye still, and there is a wide variability in retinal tissue absorption parameters. This paper describes progress in developing a computer-assisted robotic laser system that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a few seconds.

The development of a hybrid analog/digital retinal surgical laser system

In the last few years the progress made in producing an integrated automated retinal surgical laser system has grown tremendously. Two different techniques have been developed in parallel: an analog and a digital system. Both the analog and digital systems are capable of tracking the retina while precisely placing lesions in desired locations. However, each system has its unique advantages and disadvantages to an automated surgical system. Current work has been conducted to integrate these two techniques to take full advantage of their unique capabilities. The goal of this research is to successfully integrate the systems to provide a better retinal surgical treatment for those individuals affected by diabetes, retinal tears, and other eye disorders.

Development of an integrated automated retinal surgical laser system

Researchers at the University of Texas and the USAF Academy have worked toward the development of a retinal robotic laser system. The overall goal of this ongoing project is to precisely place and control the depth of laser lesions for the treatment of various retinal diseases such as diabetic retinopathy and retinal tears. Separate low speed prototype subsystems have been developed to control lesion depth using lesion reflectance feedback parameters and lesion placement using retinal vessels as tracking landmarks. Both subsystems have been successfully demonstrated in vivo on pigmented rabbits using an argon continuous wave laser. Preliminary testing on rhesus primate subjects have been accomplished with the CW argon laser and also the ultrashort pulse laser. Recent efforts have concentrated on combining the two subsystems into a single prototype capable of simultaneously controlling both lesion depth and placement. We have designated this combined system CALOSOS for Computer Aided Laser Optics System for Ophthalmic Surgery. Several interesting areas of study have developed in integrating the two subsystems: 1) "doughnut" shaped lesions that occur under certain combinations of laser power, spot size, and irradiation time complicating measurements of central lesion reflectance, 2) the optimal retinal field of view (FOV) to achieve both tracking and lesion parameter control, and 3) development of a hybrid analog/digital tracker using confocal reflectometry to achieve retinal tracking speeds of up to 100 dgs. This presentation will discuss these design issues of this clinically significant prototype system. Details of the hybrid prototype system are provided in "Hybrid Eye Tracking for Computer-Aided Retinal Surgery" at this conference. The paper will close with remaining technical hurdles to clear prior to testing the full-up clinical prototype system.

Automated retinal robotic laser system

Researchers at the University of Texas and the USAF Academy have worked toward the development of a retinal robotic laser system. The overall goal of this ongoing project is to precisely place and control the depth of laser lesions for the treatment of various retinal diseases such as diabetic retinopathy and retinal tears. Separate low speed prototype subsystems have been developed to control lesion depth using lesion reflectance feedback parameters and lesion placement using retinal vessels as tracking landmarks. Both subsystems have been successfully demonstrated in vivo on pigmented rabbits using an argon continuous wave laser. Recent efforts have concentrated on combining the two subsystems into a single prototype capable of simultaneously controlling both lesion depth and placement. We have designated this combined system CALOSOS for Computer Aided Laser Optics System for Ophthalmic Surgery. Following the dual-use concept, this system is being adapted for clinical use as a retinal treatment system as well as a research tool for military laser-tissue interaction studies.

Diastematomyelia: prenatal ultrasonic appearances

Four cases of in-utero diastematomyelia are presented and the ultrasonic features described. Characteristic findings are localised widening of the posterior ossification centres with a central echogenic focus at the point of widening, visible on coronal scanning, and absence of a posterior defect or soft tissue mass on transverse scanning. The aetiology and management of the condition is discussed. The cases illustrate that widening of the posterior ossification centres can occur in the absence of overt spina bifida and the prenatal detection of diastematomyelia will allow for early postnatal investigation and treatment.

Obstetric care in a health maintenance organization and a private fee-for-service practice: a comparative analysis

This study compares the quality of obstetric care provided for patients in two distinct groups: a federally-qualified health maintenance organization and a private fee-for-service practice. Patients of both groups were delivered in the same hospital with resident coverage equally accessible to both groups. From January, 1979, through December, 1981, the period of the study, the physician group delivered 2385 patients, 57% of them from the health maintenance organization and 43% from the fee-for-service practice. Not only were comparisons of maternal and fetal outcomes available for the two patient groups, but the yearly trends and individual performances of the physicians were available as well. This paper addresses the question, all other things being equal, is the level of care and ultimate outcome the same for both groups of patients? The results in some instances showed surprising differences.

The active management of prolonged labor

There has been growing concern in the medical community about the rising rate of cesarean sections. Use of the modified manual rotation technique on the arrested fetal head has resulted in a decrease in the number of sections, length of hospital stay, and, consequently, the cost of care.No longer is it necessary to operate on every woman who comes to the end of the second stage of labor in the persistent occiput posterior or transverse arrest position. This technique also helps to reduce, if not eliminate, the more difficult and traumatic midforcep rotations and extractions.

Computed tomography in the evaluation of a femoral aneurysm

Computed tomography was used to delineate the extent of a distal femoral aneurysm associated with arteriomegaly.

An approach to cost-containment in health care

Economic and political repercussions throughout the nation follow the unprecedented rise in the cost of delivering health care. The physician is not only a part of the problem, but also must be an active part of the solution. The author presents an approach to cost containment in health care delivery.

Flow rate determination using computed tomography

A method of measuring flow in a large vessel by using a CT scanner is described. It has been shown that this is a simple, accurate and reproducible method in an experimental model. Possible clinical applications and limitations of this method of measuring flow are briefly considered.

Assessment of abdominal aortic aneurysms by computed tomography

Images

Gray scale ultrasonic appearances of renal transplant rejection

Ultrasonic examination of renal transplants with special attention to the parenchymal echo pattern has been undertaken in 43 patients. In the normal renal transplant, the pyramids, cortex and renal sinus can be distinguished. Renal transplant rejection is manifested by swelling and decreased echogenicity of the pyramids and hyperechogenic cortex. In addition, large anechoic areas due to hemorrhagic infarcts and necrosis are seen. In long-standing rejection, a normal or small-sized kidney with an irregular intrarenal echo pattern is observed. In 13 cases of acute tubular necrosis, none of the above appearances could be demonstrated. Serial ultrasonic scans are essential to reveal evolutionary changes of the rejection process.

Computed tomographic and ultrasonic appearances of primary carcinoma of the common bile duct

Two patients with obstructive jaundice due to surgically proved primary carcinoma of the common bile duct were examined by CT and ultrasound. The combination of the two modalities showed dilatation of the extrahepatic biliary system and the main pancreatic duct. The diagnosis of primary bile duct carcinoma is suggested by these findings in the presence of a normal pancreatic head, although similar findings may occur with a small pancreatic or ampullary carcinoma.

Grey-scale ultrasonic characteristics of carcinoma of the pancreas

Fifty-five sonograms were performed on 25 cases of surgically and histologically proven carcinoma of the pancreas. The sonographic appearances of the tumour were determined. A diffuse echogenic pattern with irregular margin was the most common appearance. Displacement and indentation of the inferior vena cava and superior mesenteric vessels, greatly assist in localizing the tumour to the pancreas. A reliable prediction of tumour size and resectability cannot be determined by sonography alone. Sonography is helpful in assessing the response of unresectable pancreatic carcinoma to therapy. A more sonolucent appearance of the tumour occurs following chemotherapy.

Teenage pregnancy, a national disaster: a significant factor in black teenage unemployment

Pregnancy is an unfortunate event in the life of preteen and teenagers. Yet, it is occurring with increasing frequency among children between the ages of 12 and 16. The magnitude of this growing problem is so great it demands the assistance of all segments of society to find a solution.While it is true that pregnancy is often a social, economic, and psychological burden to the young mother, the outlook for the baby may be even more bleak. Homes and schools are not meeting the needs for rearing and training these unplanned progeny to become productive citizens. Already, some of them are entering the labor market with few, if any, marketable skills.Preventive measures seem to offer the best prospects for dealing with this human dilemma. Since the majority of the unwed teens under discussion are black, the black physician must apply his talents and resources to finding a workable solution.

Grey scale ultrasonography in the diagnosis of ectopic pregnancy

Grey scale pelvic ultrasonography was performed in 36 patients with suspected ectopic pregnancy and in 3 with pelvic mass and bleeding. Thirteen cases were diagnosed as extrauterine pregnancy which was confirmed at operation. There were one false-positive and 2 false-negative studies. The overall diagnostic accuracy was 92.3%. The major diagnostic criteria in unruptured ectopic pregnancy were an extrauterine gestational sac or fetus and an abnormal uterine echo pattern. In addition, a complex mass due to hematoma was seen in ruptured ectopic pregnancy. Chronic ruptured ectopic pregnancy simulated pelvic inflammatory disease and was difficult to diagnose.