Nuclear Imaging

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.