Spot Diagnosis
Read a concise clinical vignette, weigh the clues and commit to an interpretation. These are text-based teaching cases from the existing Nucpaedia collection.
What you will practise
- Identify the key clinical and imaging clues.
- Compare the available diagnostic alternatives.
- Review the rationale before moving to the next case.
Set up your round
145 questions available
A smaller pool gives a shorter round. In timed mode, the clock sets the round length. Prompt length is a study preference, not a validated difficulty rating.
Before you begin
Open an example to revisit its answer and reasoning.
72M, PSA rising to 2.5 after radical prostatectomy; conventional imaging negative. ⁶⁸Ga-PSMA-PET shows a single avid left external-iliac node (SUV > liver).
Nodal recurrence
ReasoningPSMA-PET is the most sensitive test in biochemical recurrence; an avid node with uptake above liver in a typical nodal station is suspicious for disease.
- PSMA-PET is sensitive even at low PSA (biochemical recurrence).
- Uptake > liver in a node = suspicious.
- Beware ganglia and ureteric activity as mimics.
55F, ileal NET, flushing & diarrhoea. ⁶⁸Ga-DOTATATE shows intense mesenteric/liver uptake; one liver lesion is FDG-avid but DOTATATE-negative.
Dedifferentiated (higher-grade) clone
ReasoningFDG-positive / SSTR-negative disease indicates a higher-grade, dedifferentiated clone — worse prognosis.
- Dual SSTR/FDG imaging = NETPET concept.
- FDG-avid discordant lesions predict worse outcome and may affect PRRT selection.
Post-thyroidectomy DTC with rising thyroglobulin; radioiodine whole-body scan is negative. FDG-PET shows an avid cervical node.
Radioiodine-refractory recurrence
ReasoningRising Tg with a negative iodine scan but positive FDG (“flip-flop”) suggests dedifferentiated, radioiodine-refractory disease.
- Tg⁺ / RAI⁻ / FDG⁺ = dedifferentiation.
- This pattern flags candidates for TKI therapy (lenvatinib/sorafenib).