Cherie...you are wrong. I know you think you're right...maybe you're Googling this stuff and you found something linking SPECT to bloodflow (which is true), but that does not mean that SPECT can depict anatomy. I suspect you've never seen a SPECT image, so I'll post one here:





SPECT shows blood perfusion to areas of the brain; it does not show anatomical structures. Neither does PET, which is why the PET/CT machine was developed. PET just shows a dark spot, but it's essentially floating - there are no anatomical structures seen. The CT scan is done immediately after the PET, while the patient is still on the table. The machine then fuses the two different scans into a single set of images which show both the lesion and its precise anatomical location:






SPECT will demonstrate that there is a lack of perfusion (blood flow) to a part of the brain, but it will not show the defect causing it.