Many people think that tests (blood work, x-rays, scans, etc.) mean their doctor is doing something constructive and working hard to figure out what is wrong. But tests are a double-edged sword.

When I trained most diagnoses were derived from careful history and a physical exam. Perhaps because our province did not have funds to have enough CT scanners and we didn’t have an MRI, those tests were on a “must have” basis only. For example, a patient with a brain tumor went down the the US for an MRI because the MRI could tell the neurosurgeon if the tumor was operable or not. As a medical student, we drew all the blood work we ordered, completed the requisition, labelled it, and sent it to the lab. On my internal medicine service that meant drawing blood on 6 or 7 patients every morning and then again later on in the day if more tests were needed. It gave me a healthy respect for how hard it is for patients to have multiple tests and of course, how it is possible to practice good medicine without a billion test results that really don’t change anything.

Tests are far from benign. The best example is a CT scan, which for a 20-year-old woman has a 1/1,000 risk of causing cancer. Yes, 1/1,000 (the risk increases the younger the patient). In addition. CT scans can have incidental findings that are benign but lead to more tests and worry. While an MRI doesn’t have radiation, a child typically needs sedation as it is essential to hold very still. In addition, an MRI tube feels like a coffin and is very loud. It can be a frightening experience for an adult, never mind a child. Blood work, while not likely to cause any long term harm is painful and if done to frequently can lead to anemia (low blood count).

So, the most important question to ask your child’s doctor when any test is ordered, especially one that hurts, requires sedation, or involves exposure to x-rays, is, “How will this test change things?”

Here are some examples:

Victor has a low thyroid and takes thyroid replacement every day. He is growing, and so his dose may or may not need to be adjusted. Being on the right dose of thyroid replacement is essential as this hormone is needed for brain growth and development. His doctor can’t tell if he is on enough thyroid medicine by an exam, so he has his blood tested every 6 months.

Oliver has moderate pulmonary valve regurgitation. The plan is to have a valve replacement when he is 18 or 19 years old. However, if his heart were to deteriorate, he might need an intervention sooner. He gets an echocardiogram every year to monitor the flow across the valve. His doctor also does an exam. the echo does not replace the heart exam, but augments it. If the exam or echo worsen, we will have to make some hard decisions.

However, there are a couple of tests that I read about on message boards that I know cause a LOT of angst for parents with premature babies and it is hard to know if they are always indicated: brain scans. I will include ultrasound, CT scan, and MRI here because they all image the brain in different ways and in my opinion way to many kids get CT scans and MRIs.

Brain ultrasounds are important in the NICU. Every baby less than 1,500 g is at risk for a brain bleed (intraventricular hemorrhage). While it may seem to many parents (and maybe even doctors) that these scans are ordered to make a prognosis about neurodevelopment, the main reason for a brain ultrasound is to pick up brain bleeds that could lead to water on the brain (hydrocephalus), because hydrocephalus may require an intervention to help a baby get their best outcome. So, the initial ultrasound is done within the first 7 days as that is when a bleed is most likely to happen, and then grade 2, 3, and 4 bleeds are followed until they resolve as these bleeds are at risk for hydrocephalus. We know that the degree of brain bleed does predict outcome to some degree, the bigger the bleed, the greater the risk of cerebral palsy and other neurologic problems; however, some babies with a grade 2 bleed get CP (my son Victor) and some kids with a unilateral grade 4 bleed do not. Because EVERY premature baby is at risk for CP the results of the ultrasound don’t really change how you follow a child long term, they just affect whether or not a baby with hydrocephalus needs treatment. In fact, 50% of low birth weight babies who develop CP have a normal head ultrasound. Yes, you read that right.

Many babies with bleeds that developed into hydrocephalus will need additional imaging studies (MRI, CT etc.), but I am amazed at the number of premature  babies who don’t have hydrocephalus who get CT scans or MRIs (remember these tests require sedation and the CT scans delivers a good whack of radiation). I read anguished messages on the Internet wondering what  a “thin corpus callosum,” a “white matter lesion,” or a “gray-matter abnormality” means?

Proponents of these scans say they help stratify which baby is at greatest risk.  And yes, moderate-to-severe white-matter abnormalities increase the risk of cerebral palsy nine-fold. And the risk of CP is increased with gray-matter injuries, but not as much as with white-matter injuries. But since ALL babies < 1,500 grams are at risk for developmental problems and CP,  all these babies still need close follow-up. In reality, a baby without hydrocephalus who has a white-matter abnormality identified on MRI doesn’t get different care (except maybe more MRIs). Because what is important is how they develop. Are they meeting their developmental milestones, or not. If they are not meeting milestones, is imaging then required? It may be, but not always.

My son Victor has dystonic cerebral palsy. He weighed 843 g at birth and had a grade 2 IVH. The bleed resolved in the NICU without hydrocephalus.

He is seven years old now. He is very stiff and is so shaky on a bicycle that we have given up trying for now. He couldn’t stand on one foot until he was 5. It took a very long time for him to get the hang of swimming and at the age of seven he is by no means a fish, but I feel if he were to fall in a pool he could keep his head above water. His digestive tract is very affected, but we have figured out ways to minimize these issues. It took countless hours of OT and thousands of hours of him practicing, but his writing is beautiful and God know where he gets his spelling ability from. He hopscotches like a pro. He is reading a grade level ahead. All without a CT scan or an MRI.

Based on his exam and his problem areas I am sure his cerebellum is a mess. In fact, I wonder if I would have pushed him so hard if I had seen a brain scan before we left the NICU?

Jennifer Gunter is an obstetrician-gynecologist and author of The Preemie Primer. She blogs at her self-titled site, Dr. Jen Gunter.