Pediatric radiology is a subspecialty that requires an additional year of training after radiology residency. At Texas Radiology Associates, we are fortunate to have two experienced pediatric radiologists in our group who are both highly dedicated to pediatric imaging and diagnosis.
There are many procedures in pediatric radiology that are similar to those done in adult patients, and many that are unique to pediatric patients. Some of the more frequently performed procedures and some common pediatric conditions are described below. For more information, or if you have a question about a procedure your child is scheduled to have done, please contact us.
Appendicitis/appendiceal ultrasound
Appendicitis refers to inflammation of the appendix. It can be diagnosed by clinical signs, symptoms, and lab values in most cases. In some cases, however, the diagnosis may not be clear based on this information. Ultrasound can be used in such cases to evaluate the appendix. Seeing an abnormal appendix on ultrasound is highly accurate in diagnosing appendicitis. Other causes of abdominal pain can sometimes be diagnosed with ultrasound when the appendix is normal.
If ultrasound is not able to confirm the presence of appendicitis, your pediatrician may order a CT scan for additional evaluation. This is a more involved study due to additional patient preparation that is needed, but is usually more helpful than ultrasound in larger or older children, or in cases where the appendix is not located in the most common position.
Bloody stools
Bloody stools in children can be due to a number of causes, which depend on the patient’s age. In infants and toddlers, a particular type of bowel obstruction called intussusception may be responsible. In older children, inflammatory conditions such as Crohn’s disease or ulcerative colitis can be the cause. Other, less common, causes of bloody stools in children include tumors and polyps. Evaluation in most cases requires a contrast enema (see below), and sometimes other tests.
Constipation
Constipation in children is often due to behavioral issues. In some cases it may be due to an obstruction or other intestinal problem. A contrast enema (see below) is often necessary to determine the cause in patients with significant constipation.
Contrast enema
This procedure involves performing an enema by using material that is visible on fluoroscopy (a closed-circuit x-ray video system) to evaluate the colon. A small tube is placed in the patient’s rectum (sized appropriately for each patient), and the colon is filled with a contrast agent (barium, water-soluble liquid, or air) during fluoroscopic monitoring. This allows the pediatric radiologist to evaluate the internal surface of the bowel and look for blockages or other problems. In certain cases, the contrast enema may also be therapeutic (see intussusception, below).
Gastric reflux
This refers to stomach contents traveling backwards, up into the esophagus and sometimes into the mouth. All infants have reflux to some extent, which is generally not a problem. In some cases, however, reflux can cause symptoms such as difficulty feeding, spitting up, gagging, or breathing difficulty. There are several ways to diagnose reflux, including the upper GI series (see below).
Hip dislocation/dysplasia, hip ultrasound
The hip is a so-called ball and socket joint. The head of the femur (thigh bone) is the ball, and the acetabulum (a rounded depression in the pelvic bone) is the socket. In some cases, this joint does not function normally due to malformation or to abnormally loose ligaments. This condition is not uncommon in babies, and can often be diagnosed by physical examination alone. Hip ultrasound is done for confirmation, or for diagnosis in equivocal cases, and is very accurate. It allows us to see the joint in its natural position and during stress maneuvers, to assess the relationship between the femoral head and the acetabulum. It can also detect the presence of abnormal fluid in the joint, and can be used to guide needle placement into the join to obtain a fluid sample. Ultrasound is most useful in babies under about 4 months of age; after that time, it is of limited value due to maturation of the skeleton that makes the hip hard to examine. At that point, x-rays are more helpful.
Intestinal malrotation/intestinal volvulus
This condition is due to a variation in development of the intestine before birth, in which the intestine may become acutely obstructed. This can cause bile-tinged (greenish) vomiting in a young infant. It is diagnosed by an upper GI series, and is a potential emergency. This condition requires surgical treatment.
Intussusception
This is an uncommon condition in which part of the intestine telescopes into an adjacent segment, causing an obstruction. It may be due to a variety of causes, including enlarged lymphatic tissue in the bowel after a viral infection, intestinal polyps or tumors, and other things. In most cases, a part of the small intestine is telescoped into the colon, blocking both. This can cause abdominal pain, and often causes bloody stools. Evaluation with ultrasound allows us to screen for other causes of abdominal pain as well as intussusception. If intussusception is present, a contrast enema (using air as the contrast agent) may be therapeutic, as the air pushes the small bowel back where it belongs. If this is not successful, intussusception must be treated surgically.
Meckel’s diverticulum
This rare developmental lesion consists of an outpouching from the small intestine that contains gastric (stomach) tissue. This tissue produces gastric acid, which can cause damage to the more delicate lining of the small bowel and result in bloody stools. There are several ways to diagnose a Meckel’s diverticulum, including an upper GI series/small bowel study and a nuclear medicine procedure called a Meckel’s scan.
Pyloric stenosis/pyloric ultrasound
The pylorus is the channel between the stomach and the small intestine, through which the stomach empties. When it becomes mildly thickened and hyperactive, it can intermittently cause obstruction. This is called pylorospasm, and generally (over 90% of the time) resolves on its own or with medication. In some cases, pylorospasm can progress to severe thickening of the pylorus, causing persistent obstruction with associated weight loss and projectile vomiting. This condition is called pyloric stenosis. Both pyloric stenosis and pylorospasm can be diagnosed with ultrasound, which allows the pediatric radiologist to measure the thickness of the pyloric muscle and to watch liquid pass from the stomach into the small bowel in real-time. In some cases, your pediatrician may order an upper GI series, which is another way to evaluate these problems.
Renal ultrasound
Ultrasound is used in cases of suspected urinary reflux and/or urinary tract infection (see below) to assess the kidneys. This allows the pediatric radiologist to detect sites of infection within the kidneys, or evidence of obstruction of urine flow from kidney to bladder. Kidney stones may also be detected with ultrasound.
Upper GI series
In this procedure, the patient is given liquid barium to drink so that x-rays of the stomach, esophagus, and the first part of the small intestine can be taken. In some cases, the entire small intestine may be evaluated (small bowel series), which requires additional barium. The upper GI series is valuable in the workup of patients with suspected pyloric stenosis or gastric reflux (see above for both) because it can also diagnose other unusual conditions such as malrotation (see above) that may require surgery.
Urinary reflux
The kidneys, located in the upper abdomen, filter the blood and make urine. Urine travels down a narrow tube, the ureter, from each kidney to the bladder. This travel should be in one direction only, toward the bladder in the pelvis. In some cases, there is abnormal reverse flow of urine from the bladder into one or both ureters, and sometimes even to the kidneys. This condition, also called vesicoureteral reflux, can be evaluated with x-ray voiding cystourethrography (VCUG; see below) or with a nuclear medicine VCUG.
Urinary tract infection
Urinary tract infections, or UTIs, are usually diagnosed from a urine sample obtained during voiding (urinating) or by catheterizing the bladder. Infection may be limited to the bladder (cystitis), or it may extend to the kidneys (pyelonephritis), potentially causing renal damage. This is more likely when reflux (see above) is present. Cystography or voiding cystourethrography (see below) may be done to evaluate the bladder and ureters in some patients with UTI.
Voiding cystourethrography (VCUG)
This procedure is often requested in cases of urinary tract infection or urinary reflux (see above). The external opening of the urethra is cleaned in a sterile fashion to limit the chance of introducing an infection into the bladder. A small catheter is then inserted into the bladder by using sterile technique. A urine sample can be obtained during this procedure, if desired by your pediatrician. The bladder is then filled with sterile contrast material (a clear, colorless liquid that shows up on x-rays), and x-ray images are taken in several positions. Additional images are taken if reflux is identified. Some patients reflux during bladder filling, while others may do so only when the bladder is completely full. Still others may only show reflux during urination. For these reasons, it is important to fill the bladder completely, though this may cause the patient some discomfort. The radiologist then watches with the x-ray camera while the patient urinates. This is done to look for reflux and to evaluate the urethra, the tube that leads from the bladder to the skin, and is especially important in male infants.
VCUG can also be done in nuclear medicine. This procedure is performed as described above. Instead of x-ray contrast, however, a tiny amount of a radio-isotope is placed in the bladder. Images are obtained with a different type of camera. A nuclear medicine VCUG involves less radiation exposure to the patient, but provides less detailed anatomic information to the radiologist. For this reason, the initial VCUG in most cases is done with x-ray contrast. Subsequent studies, if needed, can be done in nuclear medicine.
