Monday, August 15, 2005

Jeff Ballyns 5th Week

Monday: Observed Dr. Farmer perform a spinal fusion. The operation was very similar to what I had seen earlier with Dr. Sama. The same incision was made in the back cutting through the fat and then the facial muscle layer. Following that they removed the surrounding bone and cartilage that separates the two vertebrae. Then placement screws are set with aid of a CT-guide program. The program shows a 3-D representation of the patient that allows the surgeon to align the placement screws at the correct angle. Once the screws are set bars are put in place to bridge the two vertebrae together. Cancellous bone graft is the packed between the two vertebrae and the screws are torqued to align the spin to its correct and newly fused state. Below is a view of what a fisued spine looks like post operatively.

Image provided by Upstate Medical

Thursday: Biomechanics meeting-presentation of a student’s dissertation in the development of a dynamic model for the ankle joint. Prior models had assumed linearly elasticity for tendons which we now know to be viscoelastic in nature. Through the use of MR imaging he was able to reconstruct the geometry for a patient’s ankle and attach the ligaments at the correct location. The model assumed linearly viscoelasticity for the model and based the properties to that found in literature. He then manual moved the ankle and took MR scans and various positions to then compare to the dynamic model. His finding were promising but showed that further investigation needs to be done in the posterior talor ligament to characterize its behavior and function.

Friday: Met With Dr. Potter to generate a MR image of a sheep knee and high resolution with small thickness size.

Saturday, August 13, 2005

Abhishek - Patent Ductus Arteriosus

Hi all,

I have been doing rounds in the Neonatal ICU for about 2 weeks now. One of the babies is suffering from a congenital heart disease called Patent Ductus Arteriosus. The ductus arteriosus is a normal fetal structure, allowing blood to bypass circulation to the lungs. Since the fetus does not use his/her lungs (oxygen is provided through the mother’s placenta), flow from the right ventricle needs an outlet. The ductus provides this, shunting flow from the left pulmonary artery to the aorta just beyond the origin of the artery to the left subclavian artery. The high levels of oxygen which it is exposed to after birth causes it to close in most cases within 24 hours. When it doesn’t close, it is termed a Patent Ductus Arteriosus (PDA). Here is a cartoon representation of PDA -



The defect often corrects itself within several months of birth, but may require infusion of chemicals, the placement of "plugs" via catheters, or surgical closure. The flow pattern is similar to the septal defects, except that the shunting occurs outside of the heart. The left ventricle has to pump blood out through the aorta, only to have some of it flow to the lower pressure pulmonary artery, and directly back to the left atrium and ventricle. If a large PDA is not corrected, then the pressures in the pulmonary arteries may become very high and induce changes in the arteries themselves such that even closure of the defect will no longer improve the patient. In this case, the pressures in the right side of the heart are high enough that blood may begin to flow from the right to the left side of the heart. This situation is called "Eisenmenger’s syndrome", a condition which may result from several similar abnormalites. Here is an image showing the location of the PDA in a full size cartoon of the infant heart:



Surgical repair

The type and timing of surgical repair depends on the child's condition and the type and severity of heart defects. In general, symptoms that indicate that surgery is needed are -
  1. difficulty breathing because the lungs are wet, congested, or fluid-filled (congestive heart failure)
  2. problems with heart rate or rhythm (arrhythmias)
  3. excessive work load on heart that interferes with breathing, feeding, or sleeping




An incision may be made through the breastbone (sternum) and between the lungs (mediastinum) while the child is deep asleep and pain-free (under general anesthesia). For some heart defect repairs, the incision is made on the side of the chest, between the ribs (thoracotomy) instead of through the breastbone. Heart-lung bypass may be needed. Tubes are used to re-route the blood through a special pump that adds oxygen to the blood and keeps it warm and moving through the rest of the body while the repair is being done.



Most children need to stay in the Intensive Care Unit for 3 to 7 days and stay in the hospital for 5 to 14 days. By the time the child is transferred out of the intensive care unit, most of the tubes and wires have been removed and he is encouraged to resume many of his daily activities. At the time of discharge, the parents are instructed on activity, how to care for the incision and how to give medications their child may need to take such as Digoxin, Lasix, Aldactone and Coumadin. The child needs at least several more weeks at home to recover.

The baby underwent this surgery and was brought back to Neonatal ICU and remained stable after the surgery. One of the things that I noticed before the surgery took place on this baby was the condition the baby was in before he went into surgery. The team responsible for the baby took great pains to make sure that his breathing was normal and was not sick (otherwise apart from the PDA ofcourse) before he went into the OR.

Images and Illustrations provided by heartpoint.com and MedlinePlus Medical Encyclopedia.

Tuesday, August 09, 2005

Hui 4th week----Story of the pressure regulator..

I have been working on a regulating part for inflating cuffs for peripheral MRA. The cuff is placed around patient’s legs to prevent venous contamination and also movement during bolus chase using contrast agent. Currently the cuffs is hand-inflated. Leaking from connecting joints cause the pressure decrease slowly, which cause venous contamination (contrast agent flow into venous vessels) and leg movement which deteriorated images.


We need the output pressure to be stable 60mmHg (Around 1Psi) with error within 5 mmhg. Not many manufactures are making pressure regulators in such small range (most are for hundreds or thousands of Psi). After searching the internet and calling the manufactures many many times, I have had everything ordered last week.

We first intend to use the regulator with an oxygen tank that is available in every hospital and usually there is one just sit in the magnet room. Also there are oxygen outlets from the wall in the Weill Cornell Hospital.However to be safely used with the gas oxygen, all the parts have to be oxygen clean, which means suitable for use with pure oxygen. Only oxygen compatible greases can be used in oxygen-clean parts. Thus we need to make special order to ask the manufacure clean the part. However, it not only takes longer time, increase the expense, also requires that at least 10 pieces to be ordered. Fortunately we later found out that over at Columbia Hospital, they not only have oxygen but also have medical air outlets on the wall. Medical airs are just filtered air and must be much cheaper than oxygen (my guess). Even better!

Another consideration when picking the regulator and all the fittings is, they better are non-magnetic because there are a huge magnet in the scanning room. Although B decrease quickly with increased distance from the bore, it is safety requirement that no loose magnetic objects allowed in the scanning room and better anything in the room is nonmagnetic. So I was seeking for parts made from brass, aluminum, plastics, or non-magnetic stainless steal.

Thus I was able to test my non-oxygen-clean devices at Columbia. And it turns out to be great. The pressure is controlled precisely at 60mmHg. Leaking is compensated and legs are kept still.

Currently I am still optimizing the system. I just ordered a compact regulator with a compromised precise for test, and also trying to find non-magnetic alternatives for the knot, some screws in the regulator, which are magnetic.

Friday, August 05, 2005

Jeff Ballyns 4th Week

Monday: I reported to the OR at HSS at 8:30 to shadow Dr. Bostrom. While with Dr. Bostrom I was able to observe 2 total knee replacements, 2 total hip replacements and finally a total knee revision.

For those not familiar with the logistics involved in a total hip operation the basic procedures include an incision on the lateral side of the hip where the femur is dislocated so that the femoral head can be removed. The acetabulum, the surface that the femoral head articulates on, is then reamed to enlarge the area for prosthesis insertion. Finally, the prosthetic femoral head is inserted and the incision closed. The images below give a better visual representation of what would be seen on the operation table.

These images provided by Bringham and Women’s Hospital and The Legal and Legislative Resource Center

Below can be seen what some typical prosthetic hip implants look like consisting of a femoral head and an acetabular cup along with an articulating surface usually made out of polyethalyn.

Image provided by Wright

Below can be seen how these implants are viewed on an x-ray.

Image provided by Mar Vista Animal Medical Center

The total hip replacements were much different from the first surgery I had watched at HSS which was with Dr. Padget. Dr. Padget allowed Tunde, Satish, and I to observe a total hip of a dwarf woman which necessitated the use of a custom implant due to her small size. This procedure took about 2 hours because of the delicacy required when installing the artificial femoral head. Dr. Bostroms patients where of normal stature and each operation took less than an hour. Standard sized brushes were used to clear out the cortical bone from the femur and the implant was inserted with ease since a generic implant could be used making it a routine procedure.

Tunde has already described what is involved in a total knee replacement so I will not repeat what she has already presented. What I did appreciate this time around when viewing the operations was the presence of a camera that allowed me to get a birds eye view of what Dr. Bostrom was doing. I could see just exactly how each tool was attached to the knee to provide aid in making precise cuts when shaving off the femoral condyles and the tibial plateu. My final experience on Monday Dr. Bostrom allowed me to scrub in and view a total knee revision up close. Typically knee revisions are done in the case of infection, trauma, or loosening. In this case it was simply loosening of the implant due to Osteolysis. Osteolysis is bone resorption around the implant such that the implant becomes unstable and must be revised. An example can be seen below as seen by the clearing out of bone in the medial femoral condyle.

Images provided by Duke Othopeadics

Scrubbing in was quite an experience seeing just how careful one has to be once washing your hands and putting the head gear on along with the smock and gloves. Seeing the operation up close is quite a different sensation with all the new smells and seeing all the debris that is removed when changing the implant. The final implant that the patient was left with was an off center hinge joint.

One interesting things that had happened during 2 of the operations was that the patients woke up during the procedure. This typically happens to people who abuse alcohol or have high drug use. What I found so interesting was that they felt no pain in their legs even though the surgeon was using a saw and cutting bone. The reason they felt no pain in their legs was because a neurostimulator was being used. The stimulator sends electrical signals to the great sciatic nerve and its two branches the tibial nerve and the common peroneal nerve preventing any sensations of pain being delivered to the patient during the surgery.

Tuesday: Chemical Lab safety meeting for HSS

Wednesday: Dr. Potters MRI physics lecture. We discussed fat suppression techniques, truncation artifact, wrap around, and gradient echo imaging. Fat has a high signal on magnetic resonance images (MRI). This high signal, easily recognized on MRI, may be useful to characterize a lesion. However, small amounts of lipids are more difficult to detect on conventional MRI. In addition, the high signal due to fat may be responsible for artifacts such as ghosting and chemical shift. Lastly, a contrast enhancing tumor may be hidden by the surrounding fat. To improve the image fat can be suppressed by canceling out the RF peek that is representative of fat.

Truncation artifact is when part of one image crosses over to the next and it has uneven overlap. Wrap around artifact or aliasing is when tissues outside the field of view do not get properly phase encoded relative to their actual position. This excited tissue gives up signal during readout but as it has not been correctly phase encoded appears in a position other than its actual location. Anatomy outside the field of view "wraps" into the opposite side of the image. This can be corrected by scanning with a larger field of view, applying presaturation pulses to the undesired tissue, or by correctly phase encoding the extraneous tissue then discarding that information. The image below represents wrap around artifact and was provided by UBC .

Thursday: Tunde and I attended the Sports Medicine Conference. The topic was Ligaments of the Knee (conference center) viewed on MRI and was held by Dr. Potter. We then went to the Soft Tissue Lab Meeting where they discussed various articles that were recently published. Finally, we attended the Biomechanics Lab Meeting where one of the medical interns, Owen, presented his summer research project. The project consisted of analyzing the glenoids retrieved from people who had total shoulder replacements. Finally Dr. Myers gave her lecture on Statistics.

Friday: Tunde and I met with Lionel B. Ivashkiv, MD to tour his lab and discuss the summer immersion program. His laboratory studies a major signal transduction pathway utilized by many cytokines. The laboratory is characterizing molecular mechanisms that regulate signaling by the Jak-STAT pathway and attempting to develop the idea that modulation of cytokine signaling during inflammation is an important determinant of the balance of cytokine action. We are studying the mechanisms and the impact of modulation of cytokine signaling on cell function and gene expression, and on the severity of inflammation and related tissue damage. One example, is systemic lupus erythematosus (SLE), IL-10 signaling is reprogrammed such that IL-10 acquires pro-inflammatory functions and thus contributes to inflammation instead of suppressing it. A new area of investigation in our laboratory is the analysis of cytokine regulation of tissue destruction and remodeling.

Clarissa - 8/5/2005 - Carotid Endarterectomy, SilverHawk, and Brief Timeline

So, this past week was fairly busy, with my time divided between watching surgeries in the OR, seeing patients with Dr. Bush in the surgical associates clinic, and working on a timeline for the evolution of aneurysm treatments.

Carotid Endarterectomy

In the OR, most of the surgeries this past week consisted of endarterectomies (femoral and carotid), which are surgical procedures that remove plaque material from the lining of the occluded artery.

A carotid endarterectomy is shown here:



In some cases, an endarterectomy can be performed without opening up the artery in question. This would require the minimally invasive approach of using a special catheter which would travel up the artery and "shave" off the plaque on the artery wall. Such atherectomy devices remove plaque from the artery wall by cutting, pulverizing or shaving.

SilverHawk Plaque Excision Catheter

On the technology forefront is the FoxHollow SilverHawk plaque excision catheter (FoxHollow Technologies, Redwood City, CA) has been approved as of June 2003 for treating peripheral vascular disease. Previous atherectomy devices used a balloon to engage the cutting blade into the plaque, using a combination of balloon angioplasty and atherectomy that often resulted in barotrauma (or vessel overstretch). The main advantage of the SilverHawk device is the elimination of barotrauma. The SilverHawk Plaque Excision System is a two-part system that uses a low-profile catheter and a palm sized drive unit that controlls the device functionality. When activated, a tiny blade on the catheter tip rotates and shaves off thin slices of plaque from the arterial wall. After each pass, the plaque is collected into a storage chamber. When the chamber reaches its full capacity, the device can be removed, cleaned, and re-inserted to treat additional areas. The unique mechanical design of the SilverHawk catheter allows significant amounts of plaque to be removed without injuring or overstretching the vessel walls. The device is also easily positioned using fluoroscopy.

The SilverHawk is shown here:


And here is the procedure step-by-step:

The SilverHawk catheter is inserted through a small puncture site and travels through the artery to the site of blockage.


Once at the site, a tiny blade is activated by the drive unit. The rotating blade advances through the blockage, shaving off tiny slices of plaque from the arterial wall.


The plaque collects in a storage chamber at the tip of the catheter, which can be removed and cleaned.


Timeline of the Evolution of Aneurysm Treatments

Here is just a short selection of some interesting historical facts...[sorry for the empty space below, blogger doesn't seem to like tables]


















c. 2000 B.C.The Ebers Papyrus, one of the earliest known texts, contains a clear description of the diagnostic features and management of what, presumably, were traumatic aneurysms of the peripheral arteries. The Egyptians treated aneurysms with magico-religious therapies, and studies of Egyptian mummies have revealed that atherosclerosis and arterial calcification were probably relatively common.
c. 170Galen described an aneurysm as a localized pulsatile swelling which disappeared on pressure. He is considered the first to define and describe the disease, recognizing the false variety and those arising spontaneously by dilation. Considering the frequent use of venesection, and the fact that he is said to have been a physician to the gladiators, Galen probably saw traumatic aneurysms rather frequently.
c. 200Antyllus practiced an operational procedure that involved application of proximal and distal ligatures to isolate the aneurysm followed by an incision into the sac and evacuation of its contents. Antyllus believed that some of the aneurysms occurred due to simple dilation.
1510-90Ambrose Paré, the great medieval surgeon, was severely critical of any procedure that involved opening the aneurismal sac, and strongly advocated the application of a proximal ligature alone.
1550Syphilis is considered to be a cause of aneurismal dilation, and Paré also claims that aneurysms could also be caused by “anastomosis, diapedesis, rupture, erosion, and wound” and also realized that not all aneurysms are pulsatile, attributing the absence of pulsation to the large amount of thrombus in the sac.
1555Andreas Vesalius provided one of the first descriptions of an abdominal aortic aneurysm, and was first to diagnose such.
1728Lancisi in his book De Aneurysmatibus, published posthumously, discusses the etymology of the term aneurysm, and was possibly the first to infer that a congenital defect may be the cause of aneurismal dilation in some cases.
1779-93John Hunter observed that there was a communication of the arteries above the aneurysm with those below by means of anastomosing branches. He operated on a patient with a large popliteal aneurysm by exposing the femoral arterial in the subsartorial canal and by means of an eyed probe passed two double ligatures around it; the four ligatures thus created were then gently tied. This was the longest and best documented successful vascular operation yet recorded. In another experiment, Hunter exposed the carotid of a dog, dissected off much of the wall, till it was extremely thin, and blood could be seen through it. Then, three weeks later, he re-exposed the part and found no dilatation, but only a repaired vessel wall, thus concluding that pre-existing arterial disease was required to produce an aneurysm.
1864Moore introduced the technique of induction of aneurysm thrombosis by filling the sac with long lengths of coiled wire.
1900'sAtherosclerosis (Atheroma) overtook syphilis as the leading cause of aneurysms
1923Barney Brooks of Nashville was producing excellent arteriograms using intra-arterial injections of sodium iodide. Moniz further developed this technique to visualize the intracranial circulation in an attempt to improve the localization of cerebral tumours
1950Jacques Oudot performed the first successful operation for an occlusion of the aortic bifurcation using a preserved homograft and it was therefore inevitable that an attempt to perform a similar procedure on an aortic aneurysm would shortly transpire.
1951Dubost and his team in Paris performed the first entirely successful resection of an infrarenal aortic aneurysm via a thoraco-abdominal extraperitoneal approach using a frozen cadaver homograft.
1952Voorhees experimented with a polyester material known as Vinyon-N, a material easily obtained from the post-war surplus of parachute fabric. The prosthetic fabric graft provided a durable replacement for the dilated segment
1953Cooley and DeBakey used the Dubost technique to treat a ruptured abdominal aortic aneurysm, a condition that was universally lethal before graft repair
1955Albert Einstein died of rupture of an infrarenal aneurysm that had been wrapped with cellophane 6 years earlier
1966Feri accomplished superselective catheterization with minimal vessel damage with the creation of the paraoperational device catheter. To ease the difficulty of directing the paraoperational device catheter through the tortuosities of the intracranial vasculature, Frei and colleagues designed a catheter tip with an attached micromagnet. Therefore, and external magnetic field could be used to control the intravascular catheter.
1974Serbinenko published an article on balloon catheterization and occlusion which detailed an influential advancement that became a conventional treatment for intracranial aneurysms
1976-90John Parodi noted that the very patients who were at highest risk for the development of aortic aneurysms were also at greatest risk for morbidity from a major surgical intervention such as the open surgical repair of the aneurysm. Parodi and Palmaz used a device composed of Dacron tubes sutured to a Palmaz stent, compacted into a sheath, and introduced through the femoral artery, treated two patients.


More to come...

SPARC Procedure for Treating Urinary Stress Incontinence

This procedure has been patented by Dr. David Staskin and employs the suprapubic insertion of arced needles (hence SPARC) for the surgical implantation of an adjustable sling that serves to support the urethra.



This procedure treats urinary stress incontinence in women. This is the most common type of incontinence in women. The bladder is supported by muscles of the pelvic floor and if these muscles weaken, the bladder can move downward, pushing slightly out of the bottom of the pelvis toward the vagina. This prevents muscles that ordinarily force the urethra shut from squeezing as tightly as they should. As a result, urine can leak into the urethra during moments of physical stress and even mundane things such as exercise, coughing, and sneezing.


The Procedure:
This procedure is done through a ‘top-down’ (suprapubic) approach that inserts needles into the abdomen and out of the vagina. This is in contrast to other sling procedures such as the Tension Free Tape (TVT) procedure that uses a ‘bottom-up’ approach inserting needles into the vagina and out of the abdomen. There is less risk involved with the suprapubic technique of the SPARC procedure addressing the complications that have resulted from TVT use. This is an outpatient procedure that takes 20-30 minutes.


First two suprapubic incisions are made for insertion of the needles



Next a suburethral incision is made for insertion of the sling



The needles are then inserted into the abdomen and through the vaginal incision



A cystoscopy is then performed to ensure that there is no damage to the urethra or abdomen



Then sling is then snapped onto the ends of the needles and the needles are pulled out from the abdomen thereby placing the sling around the urethra



The plastic sheath covering the sling is removed and the excess sling is trimmed



The sling can be adjusted to provide the correct support and the abdominal incisions are closed and the vaginal incision is closed


Images courtesy of Dr. David Staskin

-Diego

Abhishek - Interventional Radiology

Hi all,

My last week was pretty hectic and eventful with my journey to Ithaca to make my devices work. I was in Ithaca for 4 days last week and was working on making the strain gauges work for my project in the Urology department. I have one working strain guage probe and have brought it along with me to New York city. I will be performing an experiment coming Monday. I will keep you all updated.

Interventional Radiology -

Dr. Frayer introduced me to Dr. Sullivan at Interventional Radiology. I observed 2 procedures being performed - Cardiac Catheter replacement and blod clot removal in a graft.



The procedure is performed with X-ray imaging which aids the surgeon to locate the catheter being inserted inside the patient. The X-ray machine is the semicircular machine seen in the image above and the surgeon switches on/off the x-ray with a switch using his feet.



Lead aprons are worn in the Operation room for protection from X-rays. These aprons are very heavy and be quite a weight to bear when one has to stand in the OR for more than 3 hours. The patient is usually under light sedation and has a numbing agent introduced which numbs the portion of the body where the catheter is being inserted. The catheter replacement is a routine procedure for the surgeons and the only obstacles they face is the catheter coiling up inside the vein.

The other surgery that I observed, blod clot removal in a graft, was pretty tricky and required 2 surgeons to do the job. The patient had a graft placed in his left arm which connected the artery to a vein. This graft was used for Haemodialysis and was working fine for 4 years for the patient. But recently it stopped working and he was brought to Interventional Radiology to get it fixed. The surgeons at the start of the procedure did not know that it was a clot. They at first observed the graft in the left arm using Ultrasound. They introduced a catheter close to the graft and using ultrasound imaging were able to get the catheter inside the artery and drove the catheter in. The x-rays were switched on and the catheter was observed as it moved into the artery. At one position the catheter was no longer able to move and coiled up. The surgeons after taking a lot images came to the conclusion that it was a blod clot. To remove the clot the surgeons contemplated using Heparin which is an anticoagulant but then ruled it out. This was because Heparin once introduced in the blood stream would go everywhere and remove blood clots formed to protect a previous surgical scar on the heart. The other option was to use an equipment called AngioJet Rheolytic Thrombectomy System. The AngioJet Rheolytic Thrombectomy System consists of a single-use catheter, single-use pump set, and multi-use drive unit. Thrombectomy is accomplished with the introduction of a pressurized saline jet stream through the directed orifices in the catheter distal tip. The jets generate a localized low pressure zone via the Bernoulli effect, which entrains and macerates thrombus. The saline and clot particles are then sucked back into the exhaust lumen of the catheter and out of the body for disposal. Treatment with the device takes about one minute. The surgeon informed the patient of the use of the equipment and also the complications (heart failure etc.) which may arise with its use. The surgeons inserted the catheter and flushed the blood clot using the saline jet.

The surgery on the whole was very interesting. The surgery gave me a feel of the kind of user interface the surgeons are familiar/comfortable with. I have learnt one thing that I will always remember when I design instruments/devices in the future - keep everything simple and ready to use. Its not that the surgeons don't understand how it works but its the simple fact that in the OR there is no time.

Thursday, August 04, 2005

Artificial Urinary Sphincter

This device consists of a silicone rubber cuff that wraps around the urethra near the bladder neck and is inflated manually. Several patients that visit our clinic use this device, which is used to treat urinary incontinence.



A balloon in the pelvic area regulates the pressure of the cuff and a bulb in the scrotum controls its inflation and deflation. When the cuff is inflated, the urethra is blocked and urine does not leak and when urination is desired, the cuff is deflated allowing urine to pass.





The procedure: (I’ll try to get a video of this soon)

The patient is placed in the dorsolithotomy position (laying down with legs held up and bent at the knees) and a perineal incision (incision is made in the perineum, which is the area between the base of the scrotum and the anus) is made. Colles fascia (Inner layer of superficial fascia of perineum) is being dissected off.


The bulbocavernosus muscle has been dissected off and the bulbar urethra is exposed.


The right angle is passed behind the bulbar urethra.


The measuring tape is passed around the bulbar urethra. The bulbar urethra measures 4.5 cm, so a 4.5 cm cuff is chosen for implantation.


The cuff is placed around the bulbar urethra and snapped into place.



The tubing from the cuff is passed up to the suprapubic (just above the pubic bone) wound where it is connected to the control pump.


The perineal incision is being closed. The Colles fascia is closed. The skin is closed next.


The balloon reservoir has been placed into the subrectus (abdominis rectus muscle = “six pack” muscle) space, and the control pump has been inserted into the right hemiscrotum. The connecting tubes, meaning the cuff, pump, and reservoir, are all connected.


Reference for procedure: emedicine.com

-Diego

Monday, August 01, 2005

Hui 07/29/05 Endorectal coil for diagnosis of recurrent pelvic

Today in Columbia Hospital I observed a prostate MRI using endorectal coil. Endorectal coil is one type of surface coil and is routinely used in detecting local recurrence of gynecologic tumors, prostate and rectal cancers. It is a thin wire covered with an inflated latex balloon. The coil will be positioned inside the rectum before scanning. Endorectal coil helps focus on the prostate and surrounding structures, improves ability to visualize internal architecture of the prostate and periprostatic structures, including prostate capsule and neurovascular bundles. They come in different shapes that are specifically designed for anatomical differences when imaging prostate, cervix and colorectal regions. The top one in the image is for prostate imaging.

http://www.medrad.com/products/mr/mr-coils/mrinnervu.html


The prostate is a walnut-sized gland in men. It's located just below the bladder and surrounds the urethra, the tube that carries urine from the bladder out through the penis. The main function of prostate is to produce fluid for semen. Since prostate glands lie deep inside the body and is in such a small size, it is not easy to image their detail structure using the body coil. Research showed that theie is significant difference in accuracy between body coil and endorectal coil examinations for prostatic cance [Reference: Abdom Imaging. 1996 Jul-Aug;21(4):345-52.]. Endorectal MRI may help in this situation since localizing prostate tumors with MRI appears more accurate than localizing such tumors with ultrasound. [Reference: J Urology 1999;162:1314-1317.] Thus endorectal MRI is highly recommended for detection of prostatic recurrence.

http://www.understandbph.com/BPHBasics/Anatomy.aspx?refer=GoogleProstateGland1

Hui 07/26/05 3D Gadolinium Enhanced Bolus chase MR Angiography

Early this morning, Dr.Price performed a Bolus chase MR Angiography (MRA) in an old lady with serious diabetes. The patient complained about pain in both legs especially around the calves.

Dr. Prince actually is the developer of bolus chase MR Angiography, which has been commercialized by all scanner manufacturers for performing peripheral MR Angiography.

In peripheral 3D MRA, a series of 3D acquisitions are performed following a single bolus injection of gadolinium. The bolus is chased while it is running down the legs. The patient table and the receiver coil is moved accordingly to help image different areas from abdomen down to the ankles.

The gadolinium is injected into IV using a “SmartSet” IV injection system. There are 2 syringes, separately for saline and gadolinium, connected with the tubing through an adaptor with check valves. Saline is used for test the IV initially and flushing the gadolinium at the end.

http://www.topspins.com/Smartset1.htm


At the site where main arteries are obstructed, small arteries down stream of the site of stenosis will grow largerr as a blood bypass. These vessels also get longer as they stretch to become larger in diameter make them ‘snake like’
(http://www.ajronline.org/cgi/content/figsonly/183/4/1041), which is considered as an indictor of vascular stenosis.

How to post pictures and links

Just a few tips on how to post pictures and links using HTML codes:

Posting Pictures
Use the following code:
<img src="http://www.imagesource.com/linktoimage.jpg">

Textlinks
Use the following code:
<a href="http://www.textlink.com">This is my link<a>

Email Links
Use the following code:
<a href="mailto:your address">your name</a>

Font Formatting
<font face="Arial" size="size #" color="color code">your text goes here</font>

All of the text in between <font> and </font> will be changed, but the text before and after this tag will be the default font that you set up in the basefont tag.

Bold: <b>Bold</b>
Italics: <i>Italics</i>
Underline: <u>Underline</u>
Center Align:
<center>Text you want to center</center>

Making Lists
<OL start="1">
<LI>Weill
<LI>Immersion
<LI>Program
<LI>Summer
<LI>2005
</OL>

It will end up looking like this:
  1. Weill
  2. Immersion
  3. Program
  4. Summer
  5. 2005
You can substitute OL start="1" with OL start="A" or OL start="I", for alphabetical order and roman numeral order, respectively. To make bulleted lists, use: <UL> for dots, <UL="circle"> for circles, <UL="square"> for squares.

Well, that's the basics. For more in-depth HTML and Javascript tutorials, go here: http://www.lissaexplains.com/

Hope this helps! -- Clarissa

Tunde - 3rd week

Interesting surgery
Scheduled to observe a surgery with a certain surgeon, I arrived that the OR, dressed appropriately and inquired about the surgeries scheduled for the day. But on getting to the appointed room, I was informed that the first surgery for the day was cancelled, so I had to hang out in the lounge till the next patient was brought in. On getting to the lounge, I met a friend who was to observe another surgery. He is a design engineer at HSS, and had custom designed a knee implant for a patient that was to be operated on that morning. I was invited to observe this surgery, as it was a rare and interesting case.
Though total knee replacements are common, it is apparently not common for a patient to require a custom total knee implant. This patient was a young (34yrs) female who had been though some pretty bad accidents. At the age of 5, she was in a lawn mower accident, where her left hand was injured, resulting in the amputation of that arm from elbow downwards. Then recently, she was, again, involved in another lawn mowing accident where she fractured the anterior portion of her tibia (her tibial plateau), as well as her femur (midshaft). This required a plate to be implanted on her femur to stabilize the fracture and help it heal, as well as a couple of pins on her tibial plateau to hold the pieces together. But being so young (and thus quite active), also due to the severity of the injuries and her abnormal bone structure, she developed knee problems, which eventually to her being operated on for a total knee replacement with custom implants.
I was fortunate to be able to observe this surgery, but this case proved even more interesting. Two teams of surgeons were working on her for this replacement. The first team were a group of orthopaedic surgeons, performing the total knee revision. But working right next to them, on her torso, were a group of plastic surgeons from NYP-Weill, working on harvesting some muscle tissues from the left side of her ribcage. Apparently, the injuries to her femur and knee has ripped apart must of her muscles and other soft tissue, that required an autograft of muscle tissue to help pad and stabilize her knee. I had never seen a plastic surgery, so this proved to be a very exciting and education case. the muscle tissue required was so large, that the had to make a cut from right underneath her armpit down to about hip level, to get a piece long and large enough for the transplant. This was also a lesson in human anatomy for me, and even the orthopaedic surgeons were very impressed.







Other interesting bits and pieces from my week

From MRI reading with Dr. Potter
- Syndesmosis: an articulation in which adjacent bones are bound together by a ligament. The syndesmosis of the ankle is made up of anterior tibiofibular ligament, interosseous ligament, and posterior-fibular ligaments. Following trauma to the ankle, such as an ankle fracture, the syndesmotic joint can become unstable and painful. Surgery may be needed to stabilize the syndeosmotic joint to allow these ligaments to properly heal

- Ankylosis: Stiffness or fusion of bones in a joint. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular structures outside the joint or of the tissues of the joint itself. When inflammation has caused the joint-ends of the bones to be fused together the ankylosis is termed osseous or complete. Excision of a completely ankylosed shoulder or elbow may restore free mobility and usefulness to the limb.

- Insufficiency fractures: a subgroup of stress fractures. It is caused by the effect of normal or physiologic stress upon weakened bone. Loss of bone trabeculae decreases the bone's elastic resistance. Sites frequently affected by insufficiency fractures are the thoracic vertebra, tibia, fibula, and calcaneus and they tend to occur more among older women. The most common cause of insufficiency fracture is postmenopausal osteoporosis. Other important causes are senile osteoporosis, pelvic irradiation, corticosteroid therapy, and rheumatoid arthritis.

- Osteolytic lesions: A "punched-out" area of severe bone loss. Are seen in metastatic lung and breast cancer and multiple myeloma and may cause bone pain, pathologic fractures (bones broken by disease), and hypercalcemia (high blood calcium)

- Particulate disease: Biological factors, which contribute to failure, involve local migration of wear debris from the articulating pair of the joint interface. The wear particles are believed to have the potential to form macrophages which in turn may stimulate osteoclastic activity of bone (bone resorbtion). This causes particulate disease which can lead to loosening of a prosthetic implant.

- Synovitis: inflammation of a synovial (joint-lining) membrane, usually painful, particularly on motion, and characterized by swelling, due to eff
usion (fluid collection) in a synovial sac (such as that present in the knee joint).

- Joint effusion: excessive fluid inside the joint. A joint filled with blood, rather than joint fluid, is usually called a haemarthrosis.