It is the reference examination for exploring the abdomen and the pelvis at the same time. How is the examination carried out and what pathologies is it able to identify? All the answers with Doctor Sophie Aufort, radiologist at the Clinique du Parc in Castelnau-le-Lez.
What exactly is an abdominopelvic scanner?
The abdominopelvic scanner is an imaging examination that allows the exploration, with high quality spatial resolution, of the abdominal and pelvic cavity at the same time using X-rays.The abdominopelvic scan should not be confused with theMRI, explains Doctor Sophie Aufort, radiologist at the Clinique du Parc in Castelnau-le-Lez. The scanner has a larger scanning area than theIRM. Temporal resolution is faster, since a scanner helix only takes a few seconds of acquisition (compared to 20 minutes for abdominal MRI), the head protrudes from the scanner and it makes no noise, unlike MRI. It is therefore ideal for patients who have difficulty holding their breath during an examination, the elderly, and those with claustrophobia. On the other hand, MRI has the advantage of offering greater contrast than that provided by the scanner. It will therefore be carried out as a second intention if doctors need more details in most cases.”
Why do an abdominopelvic scan?
There are two types of indications:
In the context of the emergency:
Two types of scanner can be used:
Abdominopelvic scan without injection
This is the reference examination in case of stones in the urinary tract, called urolithiasis, and also in cases of renal colitis. No product is usually injected by the medical team into the patient’s veins during the examination.
Scanner with injection
In adults, it is a reference examination in the context of an emergency which allows the medical team to detect and screen for acute pathologies of the abdomen, whether infectious, inflammatory, post-traumatic or following surgery. We can thus diagnose digestive perforations on ulcers, intestinal obstructions, colon infections such as sigmoiditisabscesses in the stomach, peritonitis, appendicitis, cholecystitis, aneurysmal ruptures or even trauma requiring emergency vascular treatment. “The most serious digestive emergency is mesenteric ischemia, specifies the radiologist. An interruption of arterial intestinal blood flow causing an infarction in the digestive tract.
In a programmed manner:
In screening for certain cancers
A virtual colonoscopy can replace colonoscopy when it is not feasible or when it is incomplete. “This examination does not have the same results as classic colonoscopy for very small polyps but remains excellent for significant nodules and polyps of more than 6 to 8 mm, specifies the specialist. The optical colonoscopy under GA therefore remains the reference examination to detect colon cancer, but in the event of contraindication to general anesthesia, patient refusal, in the event of taking anticoagulants or complex anti-aggregants to be stopped or ‘an incomplete colonoscopy is the ideal examination’. During the appointment, the patient is prepared by the medical team as for a normal colonoscopy, then the radiologist injects carbon dioxide CO2 into the colon to distend it, which allows a normal colonoscopy to be virtually simulated with endoscopic navigation. .
In order to assess chronic pathologies
In this case, the device will make it possible to research and study complex pathologies of the liver, pancreas, peritoneum, bile ducts, kidneys by carrying out several exploration helices during the same examination at different injection times. (without injection and sometimes with arterial, portal and late phases).
In pre-therapeutic assessment
The abdo-pelvic scanner allows you to prepare for a radiological or surgical intervention, by perfectly studying all the anatomical landmarks using the images. Planning an intervention is an integral part of the success of the procedure. “This is the case during an abdominal aortic aneurysm which will be treated surgically. indicates the specialist. “We need to know its size, its relationship to the renal arteries, to the iliac arteries. The treatment of an aneurysm of the spleen artery in interventional radiology requires knowing the size of the aneurysm, its neck, its precise topography on the artery, in order to choose the material which will ensure the success of the procedure.
Cancers undergoing treatment require regular exploration of the abdomen and pelvis, in order to verify the stability of the disease through a precise diagnosis, to evaluate its remission or to detect possible recurrences.
“To make an accurate diagnosis, 90% of scanner examinations must be injected,” says Doctor Sophie Aufort. “The only ones that do not require it are pathologies for which the injection will have no benefit, such as the search for stones in the urinary tract (lithiasis). For other examinations, we inject withiodine. Iodine will enhance the tissues and vessels and therefore increase the sensitivity of the diagnosis to identify visceral abnormalities..
Do you have to fast for an abdominopelvic scan?
It is important to drink plenty of water in the 48 hours before and after the examination appointment in order to help the kidney cope well with the injection of the contrast product (1.5l/day) . For the examination of the abdomen, it is preferable to remain fasting 3 hours before so as not to create interpretation difficulties linked to the presence of residual food in the digestive tract and to avoid “false positives” .
The abdominal-pelvic scanner exam: how does it work? What do we see?
During their appointment, the patient fills out a medical information form, particularly about any known allergies. The technician and the doctor look at the indication for the examination on the prescription to choose a specific protocol best suited to each request (with or without injection).
A technician (or a nurse) takes care of the patient in an individual box; he questions the patient in order to eliminate possible contraindications to the scan, then infuses him if necessary.
Often, the patient is asked to remove all metal elements (piercing, belt, etc.) which may modify the quality of interpretation of the examination. The patient then lies on a scanner with their arms raised above their head.
The patient is connected to a machine which automatically injects iodine with an average flow rate of 3 ml/second. “A helix scanner will be made in a few seconds to study the entire abdomen and pelvis”, describes the specialist. “The combination of X-rays and the injected contrast product allows for image acquisition arriving directly at the console of the manipulator and the radiologist.
Time to obtain results
Once the examination is completed, the patient can lower his arms, he is deperfused, he gets up, returns to his box to get dressed then sits down for a few minutes in the waiting room, the time to ensure that he does not develop any allergic reactions. The scan report interpreted by the radiologist is then given to him.
What are the contraindications to abdominal-pelvic scanning?
Pregnancy is a contraindication since the scanner is an examination with exposure to X-rays. It will only be used in pregnant women in cases of extreme emergency that could endanger the woman’s life.
It is necessary to know how to limit this examination exposing to X-rays, in young patients of childbearing age. “It is preferable to start with an ultrasound for pelvic pain in young women and/or an MRI, particularly in cases of chronic illness such as Crohn’s disease for example, which will require multiple imaging examinations over the course of a lifetime.signals the doctor.
There may be contraindications and side effects to injecting patients who have a problem with thyroid if they are being treated for thyroid cancer by iratherapy.
In case of’renal failure Importantly, iodine injection can cause side effects by worsening kidney function (nephrotoxic). It will be necessary to decide with the radiologist the “benefit-risk” balance to inject the images according to the degree of renal insufficiency and according to the pathology to be explored.
The famous medical questionnaire completed before the examination helps avoid errors. If a person is over 70 years old, a kidney function analysis is systematically requested before the injection in order to rule out the presence of renal insufficiency.
In case of myeloma, there may be CIs at the injection in the event of secretion of certain proteins in the urine; thus it is the hematologist who will advise on the possibility or not of injecting the patient.
Finally, it is necessary to take precautions in diabetics, by stopping treatment with Metformin 48 hours after the iodine injection. The CT scan can create side effects such as lactic acidosis in the event of treatment with Metformin.
L’allergy to iodized contrast agent (urticaria, difficulty breathing, vasomotor reaction, anaphylactic shock) exists but depending on the case this is not a contraindication to reinjecting the patient. “This question remains to be discussed with the radiologist at the time of the examination because in a large proportion of cases, these are not real allergies…