Endocrine NM

Question 1

Adrenal glands location

Answer 1

Retroperitoneum
Below diaphragm
Superior and medially to kidney
Between D12 and L1

Question 2

Glomerular zone

Answer 2

Mineralcorticoid hormones
Aldosterone - - control BP

Question 3

Fascicular zone

Answer 3

75% of cortex
Glucocorticoid
Cortisol - - glycemic control

Question 4

Reticular zone

Answer 4

Androgens

Question 5

Medulla

Answer 5

25% adrenal mass
From entoderm, chromaphine cells
Catecholamines
Adrenalin, noradrenalin
Degrade to metanephrines

Question 6

Adrenal uptake

Answer 6

Analog of cholesterol (precursor of steroid hormones)
50% modulated by ACTH
30% by RAS

Question 7

NP-59 protocol

Answer 7

I131-iodomethylnorcholesterol
1 mCi
II, IV, VII day image
High energy collimator
20-30 min, 500k-1mln counts
Photopeak 364 keV

Question 8

NP-59 preparation

Answer 8

Thyroid block 3 days before

Question 9

NP-59 uptake

Answer 9

Liver
Gallbladder
Colon (require laxative)
Add Tc-colloid - - taken up by liver - - subtraction - - adrenal visualization

Question 10

NP-59 normal

Answer 10

Symmetric uptake of adrenal on II day
Right adrenal closer to liver - - scatter - - more active uptake

Question 11

Scintadren

Answer 11

Se75-selenomethylnorcholesterol
0.16-0.22 mCi
Middle energy collimator

Question 12

Cushing

Answer 12

Hypercortisolism - - image of cortex by NP-59
ACTH-dependent - - intense symmetric uptake in enlarged glands
Cortisol hypersecreting adenoma - - monolateral uptake, contralateral not visualized
Cortical nodular hyperplasia - - bilateral asymmetric uptake
Corticoadrenal CA - - lack of adrenal glands

Question 13

Primary hyperaldosteronism

Answer 13

Conn sy
Corticoadrenal adenoma
Bilateral hyperplasia of glomerular zone
Carcinoma

Question 14

Secondary hyperaldosteronism

Answer 14

Renin elevated
Arterial hypertension
Hypokalemia
Muscular disorders

Question 15

ACTH suppression with dexamethasone

Answer 15

1-4 mg dexamethasone PO 7 days before and continue
Stop ACE inhibitor, spironolactone, diuretics
Cholesterol uptake in fascicular zone decreased
Good image of glomerular and reticular zone
DD adenoma vs bilateral hyperplasia

Question 16

Image interpretation
Limitation
Indication

Answer 16

Normal - symmetric uptake 4-5 days after
Adrenal visualization before 4th day - - adenoma (unilateral) or hyperplasia (bilateral)
Not identify adenoma in case of hyperplasia
Primary hyperaldosteronism + normal CT

Question 17

Adrenal incidentaloma

Answer 17

Benign adenoma - <3 cm, fat, <10 HU
Atypical - hemorrhage, no fat, necrosis, calcification, larger
>4 cm - malignant
>10 HU - - relative washout >40%, abs washout >60% (adenoma)

Question 18

Adrenal MTS

Answer 18

Lung
Breast
Renal
Ovaries
GIT
Lymphoma
Melanoma

Question 19

Adrenal medulla pathology

Answer 19

Pheo
Paraganglioma

Question 20

MIBG

Answer 20

Guanethidine analog
WBS, SPECT 4h and 24h
Optimal for Pheo
Identify extra adrenal Pheo, MTS, post surgery recurrence

Question 21

I131-MIBG

Answer 21

Image >24 h
False negative

Question 22

I123-MIBG

Answer 22

Higher photon flux
Greater detection
Efficiency
Better spatial resolution
Lower radiation
Easier acquisition

Question 23

Octreoscan = In111-pentetriotide

Answer 23

Somatostatin analog
WBS, SPECT 4h and 24h, >24h for uptake on abdomen
Less sensitive for adrenal lesions due to high physiologic kidney uptake
More sensitive for Paraganglioma of head and neck
More accurate in MTS

Question 24

FDG

Answer 24

Not in protocol for Pheo

Question 25

FDOPA

Answer 25

Analog of dopamine precursor Same specificity as MIBG Better spatial resolution Greater signal-to-noise ratio Esp Pheo of head and neck

Question 26

Adrenal Ca genetic

Answer 26

Beckwith - Wiedeman - - in children Li-Fraumeni - - mutation in p53 gene MEN1 25-40%

Question 27

Suspicious adrenal Ca

Answer 27

>4 cm Irregular margins Central necrosis/haemorrhage Enhancement Invasion Calcification

Question 28

Adrenal Ca poor prognosis

Answer 28

>50 years Positive resection margins N, M Poorly diff

Question 29

Functioning adrenal Ca

Answer 29

<5 cm Female Cushing Female virilization or male feminization Conn sy

Question 30

Non-functioning adrenal Ca

Answer 30

>10 cm Male Abd pain Fullness Palpable mass

Question 31

Adrenal Ca image

Answer 31

CT - study of choice to dd benign vs malignant FDG - limited uptake in adenoma, increased uptake in cancer

Question 32

Most appropriate indication for Corticoadrenal scintigraphy

Answer 32

Cortisol hypersecreting adenoma

Question 33

Suppression with dexamethasone

Answer 33

Stop ACTH stimulation - - reduce uptake in fascicular zone For hyperaldosteronism and hyperandrogenism

Question 34

Drugs interfere with MIBG

Answer 34

Tricyclic antidepressants Antipsychotics Beta blockers Reserpine Ca-channel blockers Cocaine Sympathomimetics

Question 35

Answer 35

NP-59 + Tc-colloid subtraction

Question 36

Answer 36

NP-59 Right adenoma

Question 37

Answer 37

NP-59 Bilateral hyperplasia

Question 38

Answer 38

MIBG Pheo

Question 39

Answer 39

Octreoscan Paraganglioma