INTRODUCTION The radiology is a branch of medicine that studies the human body using various energy sources following four steps: An energy source transmits energy from a given point. The energy interacts with the body part being studied. Net energy after interacting with the body is detected by various devices. Powerful computers translate the net energy displaying it in anatomic diagnostic images I functional. In the case of nuclear medicine , energy radioactive substance known as tracer is injected or ingested by the patient and distributed preferentially accumulate in the body in several systems. For example, depending on the case, the tracer can accumulate in the skeleton, the heart, or the thyroid gland. The tracer operates as if it were a "contrast" radiology except that the information derived is functional. The body emits this energy as the tracer disintegrates over time and a camera with the specialized crystals and other components detected subsequently amplify the shaking them out as images that provide a type of information that complements the anatomical image information radiological. The new hybrid technologies combine anatomical aspect of diagnostic radiology with the functional aspect of nuclear medicine. The three main methods are developed to present the PET-CT (positron emission tomography - computed tomography), SPECT-CT (single photon emission tomography With computed tomography) and PET-MRI Below, we list as a brief catalog the main radiological modalities . Radiation mode refers to the type of study. In some instances a team photo and a photo of picture type generated by …
Modalidades de Imágenes Médicas
The radiology is a branch of medicine that studies the human body using various energy sources following four steps:
- An energy source transmits energy from a given point.
- The energy interacts with the body part being studied.
- Net energy after interacting with the body is detected by various devices.
- Powerful computers translate the net energy displaying it in anatomic diagnostic images I functional.
In the case of nuclear medicine , energy radioactive substance known as tracer is injected or ingested by the patient and distributed preferentially accumulate in the body in several systems. For example, depending on the case, the tracer can accumulate in the skeleton, the heart, or the thyroid gland. The tracer operates as if it were a “contrast” radiology except that the information derived is functional. The body emits this energy as the tracer disintegrates over time and a camera with the specialized crystals and other components detected subsequently amplify the shaking them out as images that provide a type of information that complements the anatomical image information radiological.
The new hybrid technologies combine anatomical aspect of diagnostic radiology with the functional aspect of nuclear medicine. The three main methods are developed to present the PET-CT (positron emission tomography – computed tomography), SPECT-CT (single photon emission tomography With computed tomography) and PET-MRI
Below, we list as a brief catalog the main radiological modalities . Radiation mode refers to the type of study. In some instances a team photo and a photo of picture type generated by such equipment is present.
Conventional radiography is the first imaging modality. In 1895 Dr. William Roentgen discovered X-rays giving rise to the medical application thereof. X-rays are used to evaluate any part of the skeleton, including the joints and teeth; the lungs, pleura and mediastinum; the size and contour of the heart; and abdomen and pelvis to establish the pattern of intestinal gas for detection of obstruction and intestinal paralysis (ileus) and presence of stones in the urinary system, among others. Radiographs were previously used for evaluating soft tissues.
The conventional X-ray study has evolved through digital radiology that automates and streamlines the application process by reducing the X-ray dose and the number of shots. Digital radiology allows changes to the acquired image to emphasize any part of the image often ignoring repeat the study.
The conventional radiology also develops fluoroscopy which another series of studies arises. Fluoroscopy uses X rays continuous mode to observe any part of the body live instantly. Conventional X-ray fluoroscopy without applying for a discrete time to generate an image. Fluoroscopy allows a number of images in sequence and then deploy film format. Fluoroscopy allows viewing of several substances that are injected or ingested by the patient to define body parts that are not optimally evaluated by a conventional X-ray study. These substances are known as contrast media and which increase the ability of a body part differ from each other with greater precision and detail. Contrast media are administered route diversity and achieve internal organs displaying contours delineating internal operate without.
X-ray studies FLUOROSCOPY
IVP – IVP. Study the kidney function after injecting dye into a vein. It is the first study that allowed visualization of the kidneys and urinary excretion system, ureters (tubes that connect the kidneys to the bladder) and urinary bladder lesion detection and obstruction either masses, cysts, or stones. This study has been replaced by sonography which does not require radiation. The sonography has been overtaken by computed tomography (CT). The CT is superior to sonography and IVP for the detection of calcifications in the kidneys, ureters, bladder and urethra stones, and, when used to merely assess for the presence of stones, requires incurring risk of potentially adverse reaction ocasionable by contrast medium required by the IVP The IVP can detect if there are problems of filtration and excretion by the kidneys.
Cystogram – see the inside of the bladder through the urethra administering contrast.
Retrograde pyelogram – displays the ureters and collection system kidneys ureters directly by clicking through the urethra and bladder instead of then display them to manage dye into a vein in which case expect that it reaches the kidneys by circulation.
Urethrogram contrast -visualiza directly administering the urethra therein.
Barium studies – Esophagram, Upper Gastrointestinal (GI) series, Small Bowel Series, enteroclysis, and Barium Enema. For all except the barium enema, the patient swallows a white whipped barium (oral contrast), and uses fluoroscopy to look inside the digestive tract: esophagus, stomach, duodenum and small intestine as oral contrast. The barium enema involves the administration of barium through the anus to view the colon (large intestine), appendix and final part of the small intestine (ileum terminal). The Defecagram examines the rectum and pelvic muscle and ligamentous relationships during defecation using viscous barium,
Myelogram – indirectly Displays the spinal cord, the central nerve roots, and the mass effect of herniated discs or masses in the thecal sac. The thecal sac containing cerebrospinal fluid and spinal cord. The contrast is injected into the thecal sac located in the central canal of the spinal column. The contrast with the aid of fluoroscopy is injected allowing display the location of a needle through which a dye is injected. This study is almost not used as MRI can directly visualize the anatomy without placing needles in the back or neck.
Arthrogram – Displays the contents of the capsule of a joint. The contrast is injected into the joint capsule with the aid of fluoroscopy allowing display the location of a needle through which a dye is injected. The shoulder joint is the most commonly studied followed by the knee, wrist, elbow and hip. This study has been replaced by MRI. For some applications, a combined arthrogram MRI (MR arthrogram) or combined with CT, in both instances requiring the injection of a dye into the joint is made.
Sialogram – Displays the ducts of the main salivary glands (parotid, submandibular and sublingual). The contrast is injected into the hole in the ducts that drain saliva and the product was visualized with the aid of fluoroscopy.
Hysterosalpingogram (HSP) – Hystero means uterus. Salpingo means fallopian tube. The HSP displayed inside the cavity of the uterus and fallopian tubes and used for evaluating contrast female infertility by administering a tube placed in the cervix with the aid of fluoroscopy. It is intended to demonstrate that the contrast flow freely into the uterine cavity and fallopian tubes to spill into the peritoneal cavity excluding areas of scar or anatomic variants.
Lymphangiogram – This study ever conducted less frequently, visualize the lymphatic system after injection of contrast channeling small structures on the dorsum of the foot.
ERCP – Endoscopic Retrograde cholangiopancreatography – This study is conducted by the gastroenterologist. The duodenum connects the stomach to the small intestine and is accessed by a long flexible tube called an endoscope equipped with a camera. The point at which the biliary tree drain is channeled into the duodenum and contrast is injected to visualize the biliary tree and out of the liver and pancreatic duct. Today the biliary tree and pancreatic duct can be studied noninvasively by MRI using MRCP (magnetic resonance cholangiopancreatography). The MRCP can facilitate and sometimes obviate the need for ERCP ERCP is mostly used for avoiding procedures often palliative surgery.
Cholangiogram – This study displays the bile ducts after the patient ingested contrast in the form of pills that are excreted in that anatomy. Today this study is not done that way. Today, this study was performed after removing the gallbladder to ensure that there were stones in the biliary tree, among other applications. For complicated cases, the cholangiogram is performed by the interventional radiologist to view and access the biliary tree within the liver to relieve an obstruction.
The angiography is the study of blood vessels, arteries and veins, by catheterization, contrast injection and the use of fluoroscopy and conventional X-rays. This mode was digitized assuming the name of DSA – digital subtraction angiography. Angiography is used to establish whether there is obstruction by atherosclerotic plaques, thrombosis, vasculitis, dissection of the layers of the arteries, aneurysms and supplied blood to tumors, among other applications. Angiography also includes a number of invasive procedures including angioplasty, atherectomy, placement of mesh (stents), creating diversions (shunts) portosystemic, among many others.
Other invasive procedures include nephrostomy fistulogram, gastrostomy and placement of central lines for food and chemotherapy. All these procedures use fluoroscopy to guide the radiologist or other specialist.
Mammography is the application of conventional X-rays to study breast and armpit. This study also practiced less frequently in man. A mammogram is a specialized x-ray that uses a low radiation dose. During the study, the breast is compressed for a few seconds. The more compression is applied to the breast, the breast receives less radiation and tissue is increased the probability that the radiologist detects a cancer or other problems. Mammography is exquisitely sensitive to the presence of microcalcifications and, depending on their appearance, may indicate the presence of cancer.
Digital mammography achieves greater detail than conventional and often reduces the number of shots. Tomosynthesis is a scan of the sinuses which reduces the superimposition of shadows increasing the sensitivity and specificity of this study. Mammography, while not perfect since detect all breast tumors, has been instrumental in increasing survival from this disease.
Mammography is often combined with ultrasound screening. collectively known as “breast profile”, as both methods are complementary.
Biopsies of suspicious lesions can be performed by mammography (stereotactic biopsy) by ultrasound screening or by MRI, depending on which mode the suspicious lesion is best discerned. Sometimes the injury is detectable only one of these modes by what can only be biopsied or localized using this modality. These procedures can reduce the risk, cost and payback period compared with open surgery. Sometimes optimize the planning of surgery and other treatments.
Ductogram – When the nipple of expressed breast secretions of different textures and appearances is desirable to evaluate the central ducts of the breast, channeling duct openings in the nipple with a dye and getting a mammogram.
The sonography instead of using X-rays depends on sound waves to study the body. Because of this feature, sonography is the preferred modality for studying pregnant patients, gynecological organs and pediatric patients in whom it is sought to minimize their exposure to X-rays,
Sonography is the preferred initial radiographic modality for studying the gallbladder, abdominal organs (liver, spleen, kidneys, pancreas), and male pelvis (prostate and seminal vesicles) and female (uterus, cervix, vagina, fallopian tubes and ovaries). The bladder is evaluated when full of urine. The ureters transmitted pulses insertion urine in the bladder and the same are detected using Doppler in the bladder.
Because sound waves do not penetrate the air sonography is limited to the gastrointestinal system applications. The presence of too much gas in the stomach or intestine does not allow the study of monograph reliably visualize the pancreas. However, sonography is used for the evaluation of acute appendicitis and to study a predominantly pediatric condition called intussusception in which part of the bowel hernia within itself causing intestinal obstruction and other problems. Sonography highly specialized, usually only available in supratertiary hospitals and outpatient facilities will rarely, also used to evaluate the rectal wall, the wall of the esophagus and most recently joints of the musculoskeletal system to evaluate tendons and solid or cystic lesions.
More recent applications include the study of acute appendicitis, the study of breast (ultrasound screening) to complement mammography, and some joints such as the shoulder and pediatric hips. Has also become popular using sonography 3D and 4D for the evaluation of the fetus.
Sonography can also study the thyroid gland and other soft tissues of the neck, testes and adjacent anatomy and superficial blood vessels using the Doppler technique with color. The study of blood vessels is usually performed to detect areas of narrowing of the arteries due to cholesterol plaques and thrombi in the deep veins. This technique well plate directly visualize thrombus obstructing a blood vessel and setting the direction of blood flow, also calculates the blood volume per unit time and estimated blood flow velocities.
The conventional echocardiography and through the esophagus (transesophageal), usually performed by the cardiologist evaluates the performance of the heart muscle and valves, evaluate the pericardium (the sac that contains the heart) and the ascending aorta to the aortic valve stems up the left ventricle.
CT scan (Computerized Tomography, CT)
The technology of CT uses X-rays and computers to reconstruct images to study almost all parts of the body. This includes the brain, sinuses, temporal bone, orbits, neck, chest, abdomen, pelvis, and extremities, among others. At present the CT study is not indicated for breast cancer, although there have been research studies.
CT is superior to conventional radiography obtained because greater contrast between soft tissues differentiate achieving narrower range of densities and be much more sensitive and specific. Computers process information that is obtained by applying an energy source in a circular motion around a body part. The patient gets in a stretcher between a source of X-ray detectors and X-ray detectors attenuates calculate how much the body absorbs these rays. The more dense the body absorbing the X-rays (tumors, calcifications or metal), less X-rays reaching the detectors. The less dense the body part is (water, oil or air), the more X-ray detectors impact achieved. A computer translates these differences in attenuation at an image. CT machine has not changed in appearance over time. Today incapable a ct scanner spiral or helical considered virtually obsolete. Although obtain diagnostic images, a non-spiral unit takes much more time studying the patient resulting in the possibility of involuntary movement and lack of coverage of the region of interest. Any research study phase and advanced as CTA can be performed reliably on a computer not spiral CT. In a spiral CT, X-ray unit turns without stopping in a donut-shaped structure while the patient is gently slipped on a stretcher. The generated images allow a section view of the body without the superimposition of other sections, ie to isolate the anatomy is achieved as water slicing bread.
The spiral CT studies allows for faster reducing the possibility to stop covering a small section of the body because the patient could not hold your breath or did you move during the study. The CT dramatically increased the ability to detect subtle little earlier than ever before injury compared with other modalities. This study generates hundreds to thousands of images of the body region studied.
The most advanced technology of spiral CT is multidetector / multislice . Each time the X-ray unit rotates, you get more of a power information. In the past, the rotating X-ray unit and only one slice information was obtained, taking more time studying and creating other problems. With this technology, more anatomical area can be studied whenever the unit rotates. These advances achieved these studies are completed with surprisingly quickly.
The CT has also been applied to study the colon noninvasively using virtual colonography for the detection of polyps and masses, their limitation still does not perform biopsies of lesions. When lesions are detected, the patient has to undergo conventional colonoscopy. At present, medical plans do not cover virtual colonoscopy.
This method assists the radiologist in their invasive procedures such as minimally invasive guide the passage of biopsy needles for deep lesions and drain abscesses, among numerous procedures. Please refer to section Interventional Radiology later in this paper.
CTA – CT angiography allows the study of blood vessels with the benefit of an injection of dye through the intravenous route instead of the arterial route avoiding many of the complications of arterial puncture is more invasive and painful. The use of computers allows spectacular images of the arteries and veins of the body leading both isolated and in the context of the organs receiving the bloodstream are obtained. This application of CT has gained much popularity with the advancement of technology multidectector. CTA exceeds the detection MRA calcified plates cholesterol (hard plates) because CT is exquisitely sensitive to the presence of calcium in any body part.
Besides calcified plaques, the CT is excellent for detecting stones in the kidneys, ureters, urinary bladder and in the case of the male urethra. The CT has replaced IVP for diagnosis of urinary tract stones.
CT Coronary Calcium Scoring – This study of CT synchronize image acquisition with the particular patient’s heart rhythm, getting them to visualize in detail the heart arteries using gatillaje (gating) and specialized software. This study not only detects but also quantifies the amount of calcified plaque in the main arteries of the heart, assigning a score (score). The higher the score, the greater the risk of a heart attack within the next few years. The score stratifies the risk level for the patient to develop an adverse event-coronary. This study does not quantify the percentage of narrowing of the arteries and is obtained by way of screening. The study has the limitation that it does not detect soft in heart arteries plates, cholesterol plaques that form early before they calcify and harden. This means that a study with a score of 0 does not exclude the possibility of clogging the arteries of significant heart.
Recent research has documented that when the score of CT Coronary Calcium Scoring is 0, the chance of having a heart attack in the next four years is negligible and even question the need to take certain medicines to control cholesterol levels that term . The predictive value of this study is higher than the main risk factors thrown by other clinical studies. Some states like Texas have passed legislation making compulsory coverage of this study for health plans.
Coronary CT angiography (CCTA) achieves study the percentage of narrowing of the arteries of the heart produced by soft and hard plates. The latest CT equipment that have multiple rows of detectors (64, 128 and 300) and one with two X-ray tubes in the same unit have arteriogram of arteries of the heart to this challenge catheterization images conventional. Radiation doses from this study have been declining as new acquisition algorithms have been developed, now reaching levels far more acceptable than just a few years ago. This study has a very high negative predictive value; when it is negative or slightly positive, the patient usually achieved avoided a conventional catheterization. When you have intermediate or advanced disease, establishes the need for a conventional catheterization potentially with intervention by cardiologist or cardiovascular surgeon.
CTA thoracoabdominal aorta, arteries of the pelvis and lower extremedidades like the neck arteries (carotid and vertebral) and brain are successfully studied with this method. CTA exceeds MRA for detecting hard plates but at the cost of ionizing radiation and the contrast medium injection based on iodine. The dye is associated with greater likelihood of adverse reactions compared with gadolinium contrast MRA studies which use no radiation.
Magnetic Resonance (MRI)
In MRI, whatever the power of a magnet is measured in units called Tesla , abbreviated with a capital “T” in honor of Nikolas Tesla. Commercially available more powerful magnets are the 1.5 T and 3.0 T. The more powerful the magnet, more undistorted information is available for MRI antenna with a better image to detect small and subtle lesions. The more advanced the magneto programming, the range of clinical applications for patient expands.
Usually MRI technology is superior to CT for studying the brain, pituitary gland membranous inner ear, certain applications of abdomen, pelvis, joints (knee, shoulder, elbow, ankle, temporomandibular) and musculature. The MRI studies the neck and equivalently orbits than CT or CT studies the best lungs MRI
MRI instead of X-rays, uses a powerful magnet and radio frequency pulses of varying intensity applied for varying periods of time that energy deposited in the patient’s body. Energy is applied so that the information is encoded in three dimensions. Antennas (coils) capture the energy emitted by the hydrogen protons patient. A computer translates the energy released at a very detailed picture.
MRI equipment have increasingly varied considerably shortening the barrel, always open at both ends, and the present configuration approximating ring CT The latest models of open MRI are very popular for their convenience and other benefits but most use magnetos Magnetic fields are not so powerful. For advanced studies such as magnetic resonance angiography (MRA), diffusion and perfusion studies, studies of breast, abdomen and pelvis studies, studies of brain using spectroscopy and MRCP studies previously presented in this paper, the field MRI equipment high magnetic (1.5 T and 3.0 T remain the preferred radiologists in academic and research centers). On the other hand, open MRI equipment with weaker magnetic fields take longer to complete the study teams to high camp.
During the study of MRI machine emits rhythmic sounds. This does not mean that something is wrong but is part of the nature of technology. The latest versions of conventional MRI equipment have developed silent technology.
The resonance angiography (MRA – Magnetic Resonance Angiography) higher quality magnets obtained in 1.5 and 3.0 Tesla, for technical reasons. This study can replace invasive arteriography, also known as catheterization. All arteries of the body can be studied with this technique, usually using the paramagnetic gadolinium based contrast. Gadolinium is less risky than iodine-based contrast agent used in conventional arteriography. However, in patients with compromised renal function (glomerular filtration rate of 30 or less), gadolinium should be avoided because in these particular patients have reported the possibility of a condition known as neurogenic systemic fibrosis associated with morbidity and mortality.
The arteries of the neck (carotid and vertebral) and arteries of the brain (anterior artery, middle and posterior cerebral) were the first to be successfully studied non-invasive way without using X-rays through this modality. Also the thoracoabdominal aorta, pelvic arteries and arteries of the lower extremities are studied reliably. Heart arteries (MRCA) have been studied but not compared to the study by CT, the CCTA.
More recent applications of magnetic resonance imaging – MRI MRI breast and heart.
MRI is the study of choice for the evaluation of breast implants being superior to mammography and ultrasound screening. The most recent application of MRI technology is the detection of breast cancer. MRI of both breasts always performed with intravenous contrast gadolinium, is more sensitive than mammography for detecting tumors in patients with genetic factors that predispose them to develop this type of malignancy. The studio is ideal for those patients with dense breasts on mammography. The study often provides a visualized by mammography cancer is much more extensive than originally estimated and a significant percentage, I detect one second breast cancer either in the same breast or the opposite breast that was completemante unsuspected or examination physical or breast profile (mammography and ultrasound screening).
The following requirements are essential for studies of breast MRI to achieve the results published in the literature: 1) the machine can not be opened; has to be unconventional and powerful magnetic field, at least 1.5 T. 2) a dedicated breast coil is used. 3) gadolinium intravenous contrast is administered. 4) a computer program to evaluate quantitatively how and with what intensity breast lesion capture the injected gadolinium is used.
At present, the breast MRI does not replace mammography or regular physical examination or visits to your doctor. Like mammography, breast MRI is not perfect.
Heart MRI available in Puerto Rico in a handful of highly specialized centers manages multiple applications to study both the anatomy and function of the heart. Its benefit is that it does not require X-rays, intravenous contrast is not based on iodine, is more sensitive than nuclear medicine for certain types of heart attack and for the evaluation of anatomic pathology and is more specific than echocardiography to variety of conditions, supplementing the same.
Other advanced applications of MRI
Using images of diffusion and perfusion that require advanced programming MRI, you can define where and how big is the brain area infartar endangered or have already infarct (stroke). Thus, the neurologist may decide whether the patient is eligible for drugs that dissolve the clot that occludes the artery of the brain involved. The perfusion study requires the injection of intravenous gadolinium. The infusion is also used to study the level of vascularity of brain masses.
Another advanced application is the brain MRI spectroscopy . This application studies the concentration level or amount of the chemical composition of several metabolites in metabolic lesions adding information to the anatomical information from the images of conventional MRI. Diffusion Tensor Imaging studies the integrity of white matter tracts different depending on its spatial orientation referring to various injuries.
CONTRAST O “TINT” INTRAVENOUS RADIOLOGIA
The contrast material improves radiographs in the detection and characterization of an injury or further injury to those already identified in images without such contrast. Some forms require the injection of contrast such as conventional arteriography and venography and intravenous pyelogram (IVP). Other forms images thus obtained without intravenous contrast and then the same (CT and MRI).
The injected contrast to all radiological modalities except for MRI contains iodine. Injected contrast MRI and MRA most is based on another chemical element, gadolinium. Patients with a history of allergy to iodine requiring radiologic studies with intravenous contrast, are usually performed an MRI with gadolinium.
For radiological studies requiring injection of iodinated contrast material and low osmolality contrast similar to blood osmolality is less risky but is more expensive. For patients with higher risk compared to the general population to develop an adverse reaction following administration of intravenous contrast, combined steroid premedication with an antihistamine used to reduce but not eliminate the risk. This risk include patients with diabetes, any allergies to medications or iodine, asthma, multiple myeloma, some thyroid problems, sickle cell disease , cardiovascular problems, and anxious patients, among others. The iodine-based contrast could bring problems to the kidneys (it is potentially nephrotoxic) – rarely resulting in renal failure. This risk is greater in diabetic patients dehydrated. The risk of kidney damage is reduced when the patient is hydrated before, during and after injection of intravenous contrast.
Using intravenous contrast MRI contains no iodine. Containing gadolinium contrast is the least risky used in diagnostic radiology. The volume injected is less than the volume required for CT studies and less noscivo subcutaneous tissues in the case that not all the contrast between the vein and infiltrate into the soft tissues (extravasation). Although gadolinium does kidney damage in patients with GFR (glomerular filtration rate) of 30 or less, it is recommended not to inject unless a dialysis session after the MRI This coordinate is due to a recently described condition called Nephrogenic systemic fibrosis with documented morbidity and mortality.
OTHER MEANS OF CONTRAST IN THE RADIOLOGY
The radiologist also uses other contrast media to visualize the anatomy of interest varies radiological modality used. Besides the direct access to the arteries, other contrast media are administered at both ends of the gastrointestinal tract, or surgical access tract; in the thecal sac lining the spinal cord and cerebrospinal fluid containing; in some joints; in ducts of the salivary glands; and even in the lymphatic system.
The invasive radiology in many cases avoids open surgery and other directs the surgeon to make the necessary intervention has more chance of success. The procedures in this branch of radiology can reduce the risk, cost and recovery period associated with open surgery.
This branch of radiology is performed by a radiologist supervised training in this area. The vast majority of procedures performed by the interventional radiologist uses some version of contrast,
Some procedures in this branch of radiology include but are not limited to:
- biopsy using CT, stereotactic mammography, MRI, fluoroscopy and / or sonography to guide the needle
- drains pus cavities (infection)
- diagnosis of arterial and venous disease (arteriography and venography)
- uncovering of clogged arteries in various body parts using drugs, inflating a balloon (angioplasty), placing a mesh (stent)
- uncovering access obstruction in dialysis patients fistula
- obliteration of blood flow rich lesions such as some tumors, vascular malformations and aneurysms (embolization)
- creation of venous access for chemotherapy, other drugs and parenteral hyperalimentation (not oral)
- creating percutaneous (through the skin) into the stomach for liquid drug administration and food
- drainage and / or kidney obstruction relief
- drainage and / or relief of obstruction of the biliary tree
- treatment of liver tumors typically by local administration of chemotherapeutic agents, alcohol, cold or heat
- many more
PET is a type of nuclear medicine that uses the energy emitted by the patient after being injected with a tracer. The PET does not get the anatomical precision of CT and allows for the composition of an injury but establishes whether the lesion is metabolically active. Metabolically active lesions have a high probability to represent primary or metastatic cancer independent of its size. However, not all cancerous lesions are metabolically active as active infections and inflammations are hypermetabolic. And not all metabolically active lesions not exclude cancer since there cancerous lesions or grow slowly or have a particular biology that are not positive on a PET scan
The material that the patient is injected through the IV line is produced by a billionaire team called cyclotron .
The agent is commercially available 2- (fluorine-18) fluoro-2-deoxy-D-glucose – abbreviated FDG This agent is distributed throughout the body and incorporated more avidly by metabolically active cells. FDG once incorporated into the lymph node organ with metabolically active cells, preferentially accumulated emits radiation in the machine specialized PET crystals that energy detected by multiplying its amplitude with other instrumentation. The study takes preparation and coordination because, depending on the body part being studied, the patient must remain in fourth at rest, without noise and sensory stimulation. The FDA has just approved a tracer is distributed preferentially in brain neurons that have accumulated beta amyloid plaque specific for Alzheimer’s.
The main materials for PET studies infarction, heart muscle, are ammonia N-13 and rubidium 82.
In patients who have been removed a tumor tracking anatomical studies such as CT and MRI have difficulty differentiating (scar) recurrent or residual tumor and post-surgical changes. In the past months were expected to study whether these changes increase volume, remain stable or decrease its volume.
The CT is a radiological modality that uses X-rays very precisely studied the anatomy of the body as discussed previously. You can specify the exact measurement in three geometric planes, location and often the physical composition of an injury. The term composition refers in this case to determine whether the lesion consists of soft tissue calcification, fat, water, blood, air, or metal. The CT can not establish whether the detected lesion is or is not metabolically active. The use of intravenous iodine-based contrast helps to establish whether the lesion is vascular or avascular. Similar comments apply to except this modality MRI uses magnetic fields instead of x-rays and intravenous contrast is based on gadolinium rather than iodine.
One of the limitations is that CT and MRI lesions measuring less than one centimeter and larger lesions than 1 centimeter (cm) which did not display features suggestive radiological malignancy are considered indeterminate radiologically . For example, in a lung nodule with smooth margins regular composition and soft tissue calcification is an indeterminate without injury. Another example is where a patient already diagnosed with lung cancer or lymphoma in a lymph node is less than 1 cm to which he is not ascribed importance since not meets the criteria of significance because of its small size is detected when it can potentially contain tumor.
Modern computers have the ability to perform both types of study. The team is known as hybrid PET-CT scanner. This equipment enables electronic image fusion from a study of CT and PET study during the same session.
Published studies have established that studies in a unit of PET-CT are superior to a PET scan or CT study (each machine separately) performed on different machines and at different times. Clinical management is altered in a little also significant percentage of patients based on the results of the PET-CT For example, unnecessary surgeries longer made reducing morbidity and expenses and necessary surgeries that initially were not covered are performed, increased survival patient.
The main applications for PET-CT are oncology, neuropsychiatric and heart. Most tumors can be studied with this technology before starting any therapy to establish how extensive the disease (staging) to detect early recurrence (based on symptoms, elevated markers of tumor or findings in anatomical studies) and establish whether a particular therapy is or is not being effective. The last two scenarios require serial studies.
After discarding metabolic and anatomical problems through laboratory tests and scans neurodiagnostic CT or MRI, PET-CT is an excellent value to differentiate between major dementias and subsequently to guide appropriate therapy.
The first hybrid team performing PET and MRI in one session was approved in 2011. The major benefits include savings in radiation CT compared with PET-CT and greater anatomical detail possible with MRI compared with CT
The modern nuclear medicine cameras allow to obtain tomographic slices that eliminate the superimposition increasing the sensitivity and specificity of the study. The SP, E, C, T, is routinely obtained in some studies but must be prescribed by their referring physician usually after evaluating results and recommendations of radiological studies. Most modern cameras available also integrate one o’clock CT scanner to nuclear medicine camera capable of achieving SPECT This increase specificity of pathology detected by nuclear medicine images, often ignoring recommendations of further studies.
In this equipment, a wide range of nuclear medicine studies are performed.
The radiologist DIAGNOSIS
Radiology provides an extensive array of diagnostic tests that assist physicians in all specialties to establish diagnoses and treatments route as never before.
Doctors Radiologists are physicians with greater and extensive preparation for the provision of optimal radiological services. Radiologists are regularly supervised training and are certified by credencializadores agencies in the United States that monitor the quality of service and knowledge of healthcare by radiological studies. This training consists of the following fields of information:
- science of physics that apply to each radiological modality
- taking precautions against the potentially adverse effects of some forms of energy used by some radiological modalities
- quality control programs of each equipment used in humans
- greater knowledge maximize the quality of the image generated by the equipment
- commitment to keep up with technological advances in radiological modality
- skill in the interpretation of the generated images
- unique ability to translate the findings of studies in the form of a coherent and relevant radiological report with appropriate recommendations after comparisons integrating large amounts of information,
Be sure to ask if it will be a radiologist who interpreted his study of images. Do not forget to physically bring previous studies of the body part to be studied at the time of your appointment. Often only bring the result is not sufficient information. Images tell a thousand words.
Author: Dr. Fernando Zalduondo Dubner, email@example.com