Nuclear Imaging

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Cystic duct sign • Morphine is often given before 4 hours to make the diagnosis of acute cholecystitis.
Dose is 0.04 mg/kg given slowly.
Causes spasm of sphincter of Oddi
Can convert true-positive result in case of cystic duct sign to false-negative result
DIFFUSE PERIOSTEAL UPTAKE (TRAMTRACK SIGN) Criteria: bilateral, diffuse periosteal uptake
• Hypertrophic osteoarthropathy (lower extremity
> upper extremity)
• Child abuse
• Thyroid acropachy
dilated cavity on initial but not delayed images Heart size and wall thickness
• Subjective assessment
• Transient cavitary dilatation (dilated cavity on initial but not delayed images) is a sign of LV dysfunction.
Hot nose sign Imaging Findings
• No flow
Absent ICA
Absent sinuses
• Absent cerebral uptake of HMPAO
• Slight perfusion of scalp veins may be present.
• Hot nose sign: increased intracranial pressure results in increased flow to external carotid system

BraIN Death StUDY
Lambda sign and Panda sign  • Sarcoid activity
Lambda sign: bilateral hilar and paratracheal
uptake
Panda sign: lacrimal gland uptake
Rim sign:  patterNS IN hIDa StUDIeS (Fig. 12-49)
GB Not Visualized
Give morphine to increase pressure or cholecystokinin
to contract GB. Causes:
• Acute cholecystitis
Rim sign: suggestive of gangrenous cholecystitis
• Prolonged fasting
• Recent meal
Ring sign NOrMaL IMaGeS
• Slight uptake of tracer in both testes
• Testes cannot be separated from scrotum.
• Bladder activity is usually seen superior to testes.
Interpretation
Flow images
• Increased (hyperemia) or not increased (no hyperemia)
• Decreased flow cannot be detected.
Static images
• Cold testes
• Ring sign
• Hot testes

TESTICULAR IMAGING
Ring Sign
• Late torsion
• Tumor
• Abscess
Ring Sign • Late torsion
• Tumor
• Abscess
• Trauma
Ring sign or “bull's eye”

 “Nubbin sign”		 tOrSION
Imaging Findings (Fig. 12-28)
• Photopenic (“cold”) testis indicates torsion.
• “Ring sign” or “bull's eye”: peripheral rim of increased activity with central zone of photopenia may represent inflammation of dartos and infarcted/necrotic testis.

• “Ring sign”: delayed/missed torsion (the more pronounced the rim, the later the torsion or scrotal abscess)

• “Nubbin sign”: area of increased activity that extends from the iliac arteries and ends at the torsion. Indicates increased perfusion to the scrotum via the pudendal arteries.

Late torsion Variable flow images  Cold testis, hyperemic scrotum (ring sign) on static images

Testes Abscess can be seen as a ring sign 
sail sign. • Thymus uptake: sail sign.
Stripe Sign This sign refers to a perfusion abnormality with a zone of preserved peripheral perfusion. Because PE is pleural based, presence of this sign makes PE unlikely.
tie sign SUperSCaN
Criteria: diffuse high bone uptake, diminished soft tissue and renal activity, high sternal uptake (tie sign), increased uptake at costochondral junction (beading).
Metastases (usually also causes focal abnormalities)
• Prostate metastases (most common)
• Lung cancer
• Breast cancer
Metabolic
• Hyperparathyroidism
• Renal osteodystrophy
• Osteomalacia
• Paget disease (hot and cold lesions are typically combined
Myeloproliferative disease
• Myelofibrosis (large spleen)
traMtraCK SIGN DIFFUSe perIOSteaL UptaKe (traMtraCK SIGN)
Criteria: bilateral, diffuse periosteal uptake
• Hypertrophic osteoarthropathy (lower extremity > upper extremity)
• Child abuse
• Thyroid acropachy
trident sign Technique: After intrathecal injection of radiotracer, normal activity is seen in basal cisterns at 2-4 hours (trident sign), over convexities at 24 hours, and there is no reflux into ventricles. Indications: NPH, VP shunts, CSF leaks.

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