Scans

I met with a 66 year old lady to tell her the results of her investigations.

She'd been referred a month ago, with a 2 year history of memory problems. She was widowed, having a bereavement when her husband died 2 years ago. She lives alone and can't see her daughter now that she's in hospital a lot with her child who's had 9 operations and needs more. She calls the police once a month or so because the kids outside throw things at her and her neighbours windows, so she no longer feels safe (and they really do throw quite hard, I saw the dents in her garage door and the marks on her walls).

Talking with her, she had no evidence of a neurodegenerative process like dementia.

She scored normally on MMSE, Camcog and DemTect. NPI was fine, BDI II and HAD were not.

Her lack of focus seemed more to do with psychosocial stresses than through structural brain changes.

Still, since this was new to her, I thought it was worth absolutely excluding any treatable dementia, such as Alzheimer's or Lewy Body disease. As well as the raft of blood tests the GP kindly did before referring, I requested a CT scan of her brain. It came back wholly normal.

I shared the good news with her. The history, clinical course, presentation, mental state, objective cognitive assessments and brain scan all suggested she didn't have dementia. Hurrah! But before being able to move on to address her stresses and how things could be improved, she frowned and asked, "Can't you do a deeper scan, doctor?"

I explained the CT again and why there was no "deeper" scan then moved on to managing her mood and helping her cope with packages of support being offered and gratefully received. She didn't think she may need all the home care support a social worker's arranged but she is awfully grateful that all the visits and 2 days at a day centre will get her out of the house, get her talking with others once again and help her loneliness.

It got me thinking, though. A "deeper" scan? Where does this notion come from, I wonder. A plain x-ray* goes all the way through the body. Lots of them, put together to form a CT scan, also penetrate all the way through the body. MRI scan shows everything. Looking at structure of a brain, CT and MRI are perfectly good at seeing absolutely everything, no matter how "deep" it may be. CT scans are generally better at showing cerebral atrophy (which happens in Alzheimer's disease and Lewy Body disease). MRI is generally better at showing vascular damage and tiny changes of other neurodegenerative processes.

As well as the CT and MRI scans showing how the brain looks (it's structure) we can do tests to see how the brain works (it's functioning). SPECT scans look at blood flow, showing areas of poor perfusion. DAT scans show dopaminergic pathways and abnormalities that arise in Lewy Body disease.

Therefore investigations are sought to confirm or refute a diagnosis based on what's being looked for.

There isn't a better or deeper investigation to do. Which is where I started. Where did this notion that there are "deeper" investigations come from? Next time I see my lady, I'll have to ask her!


* I don't usually talk of x-rays after a harrowing experience at medical school. "X-rays are part of the electromagnetic spectrum! You' can't see them! There is no such thing as a chest x-ray at all, it's a chest radiograph!"
Exams were failed on such pedantic whimsical details, so it's stuck. I talk of "a chest film" rather than "a chest x-ray" to this day. Ho hum.