Prompt

You are examining a psychiatry registrar. A 22-year-old with first-episode psychosis has a normal neurological exam. Parents demand an fMRI and a PET scan 'to see the dopamine.' Separately, a 70-year-old with new psychosis and mild hemiparesis arrives from ED. Walk the panel through indications for structural imaging, CT vs MRI, what BOLD and PET occupancy can and cannot claim, landmark group structural evidence without group-to-person error, and how you counsel both families. Include organic red flags and incidental finding counselling.

Interpretation

Reveal interpretationShow

Case split. Young FEP without red flags: clinical diagnosis; structural MRI may be considered per local early-psychosis policy and residual uncertainty, but fMRI/PET are not diagnostic confirmations. Older patient with focal signs: urgent structural imaging and medical pathway. ^[6]^[7]

BOLD. Haemodynamic proxy; reverse inference invalid as sole mental-state decoder. ^[1]^[2]

PET occupancy. Supports excess dopaminergic tone models and version III teaching; not required before first antipsychotic. ^[3]^[4]

Group structure. ENIGMA and earlier meta-analyses show population differences; not personal tests. ^[5]

Counselling. Purpose, limits, incidental findings; normal scan does not mean non-biological illness; hope and treatment plan. ^[7]

References7Show

[1]Logothetis NK, Pauls J, Augath M, et al. Neurophysiological investigation of the basis of the fMRI signal Nature, 2001.PMID 11449264
[2]Logothetis NK What we can do and what we cannot do with fMRI Nature, 2008.PMID 18548064
[3]Abi-Dargham A, Rodenhiser J, Printz D, et al. Increased baseline occupancy of D2 receptors by dopamine in schizophrenia Proc Natl Acad Sci U S A, 2000.PMID 10884434
[4]Howes OD, Kapur S The dopamine hypothesis of schizophrenia: version III--the final common pathway Schizophr Bull, 2009.PMID 19325164
[5]van Erp TG, Hibar DP, Rasmussen JM, et al. Subcortical brain volume abnormalities in 2028 individuals with schizophrenia and 2540 healthy controls via the ENIGMA consortium Mol Psychiatry, 2016.PMID 26283641
[6]Freudenreich O, Schulz SC, Goff DC Initial medical work-up of first-episode psychosis: a conceptual review Early Interv Psychiatry, 2009.PMID 21352170
[7]First MB, Drevets WC, Carter C, et al. Clinical Applications of Neuroimaging in Psychiatric Disorders Am J Psychiatry, 2018.PMID 30173550

Interpretation

Reveal interpretationShow

BOLD. Haemodynamic proxy; reverse inference invalid as sole mental-state decoder. ^[1]^[2]

PET occupancy. Supports excess dopaminergic tone models and version III teaching; not required before first antipsychotic. ^[3]^[4]

Group structure. ENIGMA and earlier meta-analyses show population differences; not personal tests. ^[5]

Counselling. Purpose, limits, incidental findings; normal scan does not mean non-biological illness; hope and treatment plan. ^[7]

References7Show

[1]Logothetis NK, Pauls J, Augath M, et al. Neurophysiological investigation of the basis of the fMRI signal Nature, 2001.PMID 11449264
[2]Logothetis NK What we can do and what we cannot do with fMRI Nature, 2008.PMID 18548064
[3]Abi-Dargham A, Rodenhiser J, Printz D, et al. Increased baseline occupancy of D2 receptors by dopamine in schizophrenia Proc Natl Acad Sci U S A, 2000.PMID 10884434
[4]Howes OD, Kapur S The dopamine hypothesis of schizophrenia: version III--the final common pathway Schizophr Bull, 2009.PMID 19325164
[5]van Erp TG, Hibar DP, Rasmussen JM, et al. Subcortical brain volume abnormalities in 2028 individuals with schizophrenia and 2540 healthy controls via the ENIGMA consortium Mol Psychiatry, 2016.PMID 26283641
[6]Freudenreich O, Schulz SC, Goff DC Initial medical work-up of first-episode psychosis: a conceptual review Early Interv Psychiatry, 2009.PMID 21352170
[7]First MB, Drevets WC, Carter C, et al. Clinical Applications of Neuroimaging in Psychiatric Disorders Am J Psychiatry, 2018.PMID 30173550

Neuroimaging in psychiatry — structured clinical viva

Interpretation

Neuroimaging in psychiatry — structured clinical viva

Interpretation