Diagnostic Procedures

Angiography, Venography :

This procedure is to study the blood vessels. The arteries are catheterized usually through the femoral artery & after injection of iodinated dye, x-rays are taken. If the same study is performed for the veins, we get venograms.

 

Barium studies:

Barium Swallow: This is a short and painless study for the esophagus and takes 10-15 minutes to perform. No preparation is required. Patient is asked to swallow the barium liquid and X-rays are taken as required.

Barium Meal: It is also a painless study for the stomach (duodenum). It takes up to 20-30 minutes to perform. Patient is asked to report on empty stomach after overnight starvation. Gas producing powder is also used to give better quality X-ray pictures.

Barium Meal follow through: It is a study for the small bowel. Patient is asked to take laxative tablets for clearing the bowel in addition to overnight starvation and report on empty stomach. Patient is given barium to drink and X-ray pictures are taken at periodical interval. The duration of the examination depends on how soon the barium passes through the small intestine. Sometimes ’24 hour’ film is also taken in which pictures of the left over barium in the intestine is taken. The study is not painful but waiting may be a little boring.

Small bowel enema: When detailed information is not available after the barium follow through patient has to go for small bowel enema. Patient has to report on empty stomach after overnight starvation with laxative tablets on night preceding the examination to clean the bowels. For this procedure a long rubber tube is passed through nostril/mouth into the small bowel. Barium is injected and X-ray pictures of small intestine are obtained.The procedure takes about one hour.

Barium Enema: This examination is to visualise the large intestine. Patient is asked for overnight fasting with liquid diet the day before and aggressive clearing of the bowel with laxative tablets the night before and in the morning. A thin suspension of barium is introduced into the large bowel through an enema tube, pushing of air is followed. Serial X-ray pictures are obtained under fluoroscopy to depict the various parts of the large intestine.

 

Colour Doppler :

Diseases of the blood vessels are evaluated with the use of an ultrasound machine equipped with colour doppler facilities. Using the doppler principle of changing pitch with velocity, ultrasound waves that reflect from the red blood corpuscles in arteries and veins are evaluated for velocity and amplitude and colour maps of the vessels can be generated. Colour doppler is very useful in evaluating the carotid arteries in the neck, the heart, the arteries and the veins in the abdomen and the arteries and veins in the upper and lower limbs. No special preparation is required for this.

Computerised Tomography (CT Scan) :

Ordinary x-ray pictures are one dimensional representations of the body parts whereas C.T. allows us to section the body to look at its insides. Thus, the skull x-ray shows us the outside,whereas CT shows us the brain inside. For plain CT scan no preparation is required. However to enhance the ability of the CT scans to pick up the abnormalities intravenous injections of iodine based contrast are used. For this injection patients are usually asked to starve for 4 to 6 hours prior to the procedures. Also for some special abdominal scans patients are asked to drink about 2 glasses of contrast medium before the scans.

In case of the patients with the previous history of reactions, bronchial asthma, renal & cardiac failure or reactions to the other drugs, " Non-ionic contrast media" can be used which have an incidence of reactions which is less than one percent. The Non-ionic contrast media are four times as expensive as ionic contrast media. However, if the patient desires we can use Non-ionic contrast media.

3 D CT , Dental CT, Real Time multiplanar reconstructions , high resolution CT, Dynamic CT & Spiral CT are the newer advances of the CT scan available.

 

Dacryocystography :

In a few cases of excessive watering of the eyes, a Dacryocystogram is advised by the ophthalmologist. This investigation is done to check the patency of the nasolacrimal duct, which is a small tubular passage which drains the tears from the eyes into the nose. No preparation is required for the procedure. A small cannula ( blunt needle) is introduced into a normally present hole on the lower eyelid. When this is done, there is no or very little pain or discomfort. Through this cannula, contrast medium is injected. There will be no pain when this injection is made; often there is a salty taste in the mouth as the contrast injection normally flows to the back of the mouth.

 

Fistulogram & Sinusogram:

This procedure is done to identify the tract of the sinus or fistula. Dye is injected into the cutaneous sinus or fistula and x-rays are taken.

Hysterosalpingography (HSG):

This procedure is usually done on the 9^th or the 10^th day after the onset of menses to visualize the female reproductive system i.e. uterus & fallopian tubes. The cervix is cannulated & iodinated dye is injected into the cervical & uterine lumen. The fallopian tubes are well seen.

Magnetic Resonance Imaging (M.R.I.) :

This examination does not used X-rays.The body is placed in a strong magnetic field & various parts of the body are excited using specific magnetic pulses. The way in which tissues interact with these magnetic pulses, gives rise to electromagnetic signals which are converted into images. M.R.I. is most useful for investigating various disorders of the brain, the spinal cord, blood vessels, muscles, joints & the heart.

Patients with metallic implants such as pace maker, nails, aneurysm clips etc. may be affected & thus these patients should not be scanned with M.R.I.

Some patients while lying inside the machine may feel claustrophobic, for these patients there are the newer ‘ Open magnet system’, which is open from the three sides, makes the M.R.I.scan a very pleasant experience. No pre procedure preparation is required.

Newer advances in M.R.I. are :

• M.R.Angiography – The ability to visualize vascular structures without injections.

• M.R.Spectroscopy -The ability to evaluate biochemical parameters of tissues. M.R.C.P - The ability to look at the biliary system.

• M.R.Arthrography – The ability to look at the shoulder joint & its content.

 

Mammography :

Mammography helps in the diagnosis of the breast lump, i.e. whether it is benign or malignant and thus screens normal women for early breast cancer. Small densities can be seen on mammography much earlier than when it forms a mass, which can be felt. Generally it is suggested to go for mammography test once in a year for the women above the age of 40 years. However a patient feeling lumps, nipple discharge, skin discoloration, lump in the armpit should immediately go for mammography test. Ultrasound of the breast is called sonomammography.

Myelography :

This procedure is used to investigate symptoms arising out of compression of nerves & the spinal cord within the spinal column. Non-ionic, iodinated contrast medium is injected through a lumbar puncture. The patient has to starve for about 4 hours prior to the procedure. After the contrast injection the patient is examined in various positions.

Orthopantomography :

This is a special method for obtaining radiographs of the teeth- bearing jaws, both upper and lower. A specially constructed machine rotates around the jaw-bones, thus giving us an extremely good idea about the structure of the jaw-bones and are useful in a wide-variety of conditions including infections, tumors, congenital abnormalities, pre-implant evaluation and trauma. Cephalogram is an x-ray of the face, obtained so that accurate measurements of the face can be performed.

 

Sialography :

This procedure is done to identify the parotid duct and gland under the fluoroscopy. No preparation is required. The parotid duct is cannulated from the mouth and x-ray pictures are taken.

Ultrasonography :

In Ultrasound,sound waves of high frequency is used to produce images. When high frequency ultrasonic waves pass through different parts of our body, these parts response differently. Many tissues reflect these sound waves partially & transmit the rest, which are then reflected back from more deeper structures.The reflected waves are measured & depending on the time it takes for them to return, the depth of the echo is decided – The intensity decides the grayness of the area. Ultrasound is used in many parts of the body, specifically to look at the fetus, for other gynaecological abnormalities & to look at the abdomen,orbits,thyroid glands,breast,testes.This examination is not very useful for evaluation of diseases of the brain and chest.Ultrasonography of abdomen requires prior preparation.

Higher resolution scanning for small areas such as the superficial ligaments & tendons of the body, doppler which allows examinations of blood vessels & 3 D ultrasound which allows 3 dimensional studies of various parts of the body are the newer advances in ultrasound.

 

Urethrographies:

Intravenous Pyelography (IVP) / Intravenous Urography (IVU):

This examination is for the kidneys, the ureters and the urinary bladder. The patient is asked to starve overnight and report on empty stomach taking laxatives for two nights prior to the procedure. A plain X-ray of abdomen is taken to check the feces and gas. Once the preparation is satisfactory; an intravenous iodinated contrast injection is given and x-ray pictures are taken.

Micturating cystourethrogram (MCU):

Generally performed in men to study the urinary bladder and the urethra. Patient is asked to refrain from drinking water for several hours before the procedure. Dye is introduced into the urinary bladder and the patient is asked to micturate/urinate. X-ray pictures are obtained during the act of micturation to assess the functioning and structure of the urinary bladder and urethra.

Retrograde Urethrography (RGU) :

Dye is injected through the urethra from the glans penis & X-ray pictures are taken.This helps in assessing the urethra and the bladder base.

Dynamic Retrograde Urethrogram (DRU) :

To look for the passage through which urine is passed, this procedure is done in males. No prior preparation is required. Contrast media is injected into the urethra & X-rays are obtained.

X-Rays:

About X-Rays

Prof. W.C. Roentgen discovered the mysterious X-rays on 8^th November, 1895.

X-rays are electro-magnetic radiations which are neither seen nor felt nor heard and are produced by special machines called X-ray machines.

When X-rays pass through the body they come out with different strengths as different parts of the body behave differently with X-rays. After passing through the body these X-rays expose the photographic film, which is then developed to see the final picture.

X-rays specifically are useful for the chest, the bones, the joints and the abdomen.

The advances in X-rays like CT Scanning and digital radiography too use X-rays. In emergency situations such as the trauma centre and intensive care unit images are directly produced on a computer, bypassing the film.

Improved quality of equipments and the radiation protection standards made the X-ray examinations very safe. However safety precautions should be observed while dealing with the young patients (protect their reproductive organs) and the pregnant ladies. X-ray examinations during pregnancy may have adverse effects on the unborn child, which includes malformations of the fetus, and increasing chances of childhood leukemia (these risks are maximal in the first three months of pregnancy). Thus X-ray examinations and CT scans, in pregnancy should not be advised unless it is absolutely essential. MRI and Ultrasound examinations are safe during pregnancy.

About the dyes used:

Artificial dyes are used to obtain clear view of the internal structures of the body. These contrast media are used in ‘procedures’, in CT scans and during MRI.

Reactions of these dyes are very rare and uncommon but very few patients may get reactions like nausea and redness of skin. To avoid these complications a special dye, which is more expensive, but safer should be used.

Commonly used dyes are:

Barium: It is a barium sulphate powder used for investigations of the gastro-intestinal tract. Barium is an inert substance that coats the internal lining of the bowel and fills up its lumen. It is radio-opaque and thus seen very well on X-rays. These agents are harmless which are passed out of the body in the stools in a day or two. Barium liquid is also used in enema for the study of the large intestine.

Iodine: For radiological investigations such as IVPs, angiographies CT Scans etc various organic compounds of Iodine are used. When these agents are injected (intravenously), it is usual to have a feeling of warmth and a metallic taste in the mouth. Adverse reactions can occur very very rarely with the ‘non ionic’ contrast agents but these non ionic contrast media are not recommended as they are up to five times more expensive than the ‘ionic’ contrast agents.

Gadolinium: During some MRI examinations various compounds of Gadolinium are injected intravenously, which are very safe and adverse reactions are infrequent.