Femtosecond Laser in Cataract Surgery

Conventional Method

Current conventional method for cataract surgery involves making a small incision in the cornea, followed by an incision in the front of the capsule of the lens also called a capsulotomy. The procedure opens up the capsule and through an ultrasound probe inserted with high frequency sound energy, the lens is fragmented in situ. This process is called phacoemulsification. The fragments are then aspirated out. The entire process can ocassionally cause damage to other nearby structures and lead to complications of the eye. The lens capsule is kept in place so that an artificial intraocular lens (IOL) can be implanted. Once implanted within the capsule, the IOL restore the vision.

Femtosecond Laser Assisted

The femotosecond laser systems are designed to assist surgeon make more precise cuts in a target area without damaging the surrounding tissues. Femtosecond lasers emit optical pulses of extremely short duration in the domain of femtoseconds as short as one quadrillionth (10⁻¹⁵ s) of a second. These ultra-short pulses are too brief to cause damage to tissues.

Femtosecond laser systems combined with an ocular coherence tomography (OCT) system is able to produce cross-sectional and three-dimensional images of an image of the eye. The laser's high-resolution OCT helps the eye surgeon visualize the cornea and the lens by constructing a 3D image of the cornea, iris, and anterior and posterior capsules with micron-level sensitivity and leading them to perform precise centered shapes and patterns to be cut at predetermined widths and depths into the capsule. The level of precision of the incisions is greater than that achievable by convectional manual means. 

In addition, the femtosecond laser can also perform capsulotomy and lens fragmentation as well as precisely delineate the surgical incisions. Theoretically, if we can make the capsulotomy of a consistent diameter and position then we may have better control over the effective lens position, which in turn could lead to more predictable refractive outcomes.

Femtosecond laser systems can produce perfectly centered and circular capsulorhexis, pre-fragment dense cataracts with minimal collateral damage to corneal endothelium, perfect capsulorhexis in subluxated cataracts without zonular stress. 

Information on this page is provided for interest only on a "best efforts" basis and does not 
constitute personal advice. Always discuss medical conditions and related matters with your doctor.

Ref: http://www.reclaimyourvision.com/cataract/lensx-laser-surgery.shtml

Cardiac Computed Tomography (CT)

Cardiac CT

 

Cardiac CT is a heart-imaging test that uses CT technology with or without intravenous (IV) contrast (dye) to visualize the heart anatomy, coronary circulation, and great vessels (which includes the aorta, pulmonary veins, and arteries).

 There are several types of CT scans used in the diagnosis of
heart disease, including:

• Calcium-score screening heart scan
• Coronary CT angiography (CTA)
• Total body CT scan

 

Calcium-Score Screening Heart Scan

The calcium-score screening heart scan is a test used to detect calcium deposits found in atherosclerotic plaque in the coronary arteries. State-of-the-art computerized tomography methods, such as this one, are the most effective way to detect early coronary calcification from atherosclerosis (hardening of the arteries), before symptoms develop. The amount of coronary calcium has been recognized as a powerful independent predictor of future heart problems and is useful in making lifestyle changes and guiding preventive care to reduce their risk.

 Your doctor uses the calcium-score screening heart scan to evaluate risk for future coronary artery disease. If calcium is present, the computer will create a calcium "score" that estimates the extent of coronary artery disease based on the number and density of calcified coronary plaques in the coronary arteries.

Absence of calcium is considered a "negative" exam. However, since there are certain forms of coronary disease, such as "soft plaque" atherosclerosis, that escape detection during this CT scan, it is important to remember that a negative test indicates a low risk, but does not absolutely exclude the possibility of a future cardiac event, such as a heart attack. The calcium-score screening heart scan takes only a few minutes to perform and does not require injection of intravenous iodine.

Coronary CT Angiography (CTA)

Coronary computed tomography angiography (CTA) is a noninvasive heart imaging test currently undergoing rapid development and advancement. High-resolution, 3-dimensional pictures of the moving heart and great vessels are produced during a coronary CTA to determine if either fatty or calcium deposits (plaques) have built up in the coronary arteries.

Before the test, an iodine-containing contrast dye is injected into an IV in the patient's arm to improve the quality of the images. A medication that slows or stabilizes the patient's heart rate may also be given through the IV to improve the imaging results.

During the test, which usually takes about 10 minutes, X-rays pass through the body and are picked up by special detectors in the scanner. The newer scanners produce clearer final images with less exposure to radiation than the older models. These new technologies are often referred to as "multidetector" or "multislice" CT scanning. 

Another new technology, known as dual-source CT, uses two sources and two detectors at the same time. This technology provides full cardiac detail with about 50% less radiation exposure than traditional CT.

Since it's noninvasive, a coronary CTA can be performed much faster than a cardiac catheterization (also called a "cardiac cath" or coronary angiogram), with potentially less risk and discomfort to the patient, as well as less recovery time. Although coronary CTA exams are growing in use, coronary angiograms remain the "gold standard" for detecting coronary artery stenosis, which is a significant narrowing of an artery that could require catheter-based intervention (such as stenting) or surgery (such as bypassing) to treat the narrowed area. However, coronary CTA has consistently shown the ability to rule out significant narrowing of the major coronary arteries. This new technology also can noninvasively detect "soft plaque," or fatty matter, in the coronary artery walls that has not yet hardened but that may lead to future problems without lifestyle changes or medical treatment.

Coronary CTA is most useful to determine whether symptoms of chest pain may be caused by a coronary blockage, particularly in individuals that may be at risk, such as those with a family history of cardiac events, diabetes, high blood pressure, smokers, and/or those with elevated cholesterol. However, there is still much controversy as to when a coronary CTA should be used. 

Total Body CT Scan (TBCT)

The total body CT scan, or TBCT, is a diagnostic technique that uses computed tomography to help identify potential problems or diseases before symptoms even appear. 

The TBCT scan -- which takes about 15 minutes to perform -- analyzes three major areas of the body: the lungs, the heart, and the abdomen/pelvis.

In the heart, the scan can detect aortic aneurysms and calcium deposits within plaque in the coronary arteries. However, the presence of calcium deposits in the coronary arteries does not necessarily mean that an artery is dangerously narrowed by disease or that a severe health threat exists. For example, calcium deposits are often found in older people as a result of their age. In addition, the CT scan cannot give a precise location of the diseased portion of the artery.

For some high-risk individuals, the proposed benefit of having a TBCT scan lies in the potential of early detection and treatment. But overall, its use for early detection of heart disease is very controversial.

Source : http://www.webmd.com/heart-disease/guide/ct-heart-scan?page=3

Artificial Intelligence in Medicine

Clinical Decision Support System (CDSS)

Today computerised power is moving towards assisting in medical diagnosis.
Computer software designed to assist physicians and other health professionals with quick guidance in decision making into the diagnosis of patients' condition and treatment.

A clinical decision support system is an active knowledge system which uses two or more items of patient data to generate case-specific advice. A CDSS makes suggestions of outputs or a set of clinical outputs from the patient data for the clinician to make appropriate diagnoses.  Doctors use these systems at point of care to help them as either in pre-diagnoses, during diagnoses, or post diagnoses.

Pre-diagnoses CDSS systems are used to help the physician prepare the diagnoses. CDSS used during diagnoses help review and filter the physician’s preliminary diagnostic choices to improve their final results. And post-diagnoses CDSS systems are used to mine data to derive connections between patients and their past medical history and clinical research to predict future events.

Knowledge-Based CDSS

Most CDSS consist of three parts, the knowledge base, inference engine, and mechanism to communicate.

The knowledge base contains the rules and associations of compiled data which most often take the form of IF-THEN rules. If this was a system for determining drug interactions, then a rule might be that IF drug X is taken AND drug Y is taken THEN alert user. Using another interface, an advanced user could edit the knowledge base to keep it up to date with new drugs.

The inference engine combines the rules from the knowledge base with the patient’s data.

The communication mechanism will allow the system to show the results to the user as well as have input into the system

Non-Knowledge-Based CDSS

CDSS uses a form of  artificial intelligence called machine learning, which allow computers to learn from past experiences and/or find patterns in clinical data.

Electronic Medical Records (EMR) and CDSS

By incorporating EMR and CDSS it has the potential to change the way medicine has been taught and practiced . As it is said that, “the highest level of the EMR is a CDSS”.
Since “CDSS are computer systems designed to impact clinician decision making about individual patients at the point in time that these decisions are made”, the reasons can be seen why it would be beneficial to have a fully integrated CDSS and EMR.

Even though the benefits can be seen, to fully implement a CDSS within an EMR, it will require significant planning by the healthcare facility/organisation, in order for the purpose of the CDSS to be successful and effective. The success and effectiveness can be measured by the increase in patient care being delivered and reduced adverse events occurring. In addition to this, there would be a saving of time, resources, autonomy and financial benefits to the healthcare facility/organisation.

Benefits of CDSS and EMR

There has always been errors that occur within the healthcare industry, thus trying to minimise them as much as possible in order to provide quality patient care. Three areas that can be addressed with the implementation of CDSS and Electronic Medical Records (EMRs), are:

1. Medical error
2. Medication error
3. Adverse drug events

CDSS will be most beneficial once the healthcare facility is 100% electronic thus simplifying the number of modifications that have to occur to ensure that all the systems are up to date.


Reference: en.wikipedia,org/wiki/clinical_decision_support_system