^99mTc-Sestamibi/¹²³I Subtraction SPECT/CT in Parathyroid Scintigraphy: Is Additional Pinhole Imaging Useful?

Table 3

False-negative and false-positive findings with –sestamibi/¹²³I subtraction SPECT/CT alone and with an additional pinhole image. Case number with a letter (a and b) refers to the same patient.

Case number	Location	Clinical background	SPECT/CT	SPECT/CT with pinhole	Comment
1	LL	pHPT	FN	TP	Residual activity was faintly visible in SPECT/CT, but was classified as negative. With additional pinhole image correct classification was done.
2	UL	pHPT	FN	TP
3a	LL	sHPT	FN	TP
4a	LL	pHPT	FN	TP
3b	LR	sHPT	FN	FN	No clear residual activity
5a	UR	pHPT	FN	FN
6	UR	pHPT	FN	FN
7	LL	pHPT	FP	TN	Very uneven iodine uptake
4b	UR	pHPT	FP	TN	Subtraction artefact (edge effect)
8	LL	pHPT	FP	TN	Subtraction artefact (edge effect)
9	LR	pHPT	FP	TN	An iodine-negative nodule
5b	LL	pHPT	FP	FP	A large thyroid cyst at left side
10a	LR	pHPT	FP	FP	Subtraction artefact
10b	LL	pHPT	FP	FP	Subtraction artefact

UL = upper left; LL = lower left; LR = lower right; UR = upper right.