Radiology Notes

My notes during radiology residency, fellowship, and beyond…

Archive for the ‘nuclear medicine’ Category

Renal Scintigraphy

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MAG-3 or DTPA

  • Perfusion/Obstruction
  • normal uptake 50/50 L and R kidney; >60/40 is abnormal
  • normal peak < 5 minutes
  • normal residual coritcal activiy < 0.3
  • Lasix
    • increases urine output
    • inject 15 min before MAG3/DTPA
    • no washout after Lasix = obstruction
    • normal T1/2 = < 10 min
    • obstructed T1/2 = >20 min
  • Captopril
    • evaluate renal artery (renal artery stenosis, ischemia, renovascular hypertension)
    • baseline scan, captopril scan, post scan
    • high prob RVH = marked captopril induced changed

DMSA = Morphology

  • for UTI or pyelonephritis, congenital malformation
  • cold spots: pyelonnephritis, tumors, cyts, hydronephrosis, trauma, infarct

Radionuclide Cystogram

  • UTI, VUR
  • sulfur colloid, DTPA, MAG-3
  • fill bladder until reverse flow

Source: ppt

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Written by lmwong

March 31, 2010 at 10:39 am

Posted in nuclear medicine, renal

3 Phase Bone Scan Interpretation

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3 phases: Flow, Blood Pool, Delayed

  • Cellulitis: +/+/-
  • Osteomyelitis: +/+/+
  • Fracture: +/+/+
  • Noninflammatory: -/-/+

Written by lmwong

March 23, 2010 at 9:18 am

Thyroid Uptake Imaging

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  • I-123 = 200-600 uCi; 99mTc-pertechnetate = 5-10 mCi
  • normal
    • homogenous
    • approx. 2 x 5 cm
  • ectopic thyroid: neck, base of tongue, ovary (struma ovarii), mediastinum; L>R
  • congenital organification defect = no activity
  • cold nodules
    • colloid cyst (MC)
    • adenoma
    • carcinoma (MC papillary)
  • hot nodules
    • hyperfunctioning adenoma (MC)
    • carcinoma
  • multinodular goiter
  • diffuse increased uptake
    • Graves disease = diffuse toxic goiter
    • Thyroiditis (Hashimoto’s)

Written by lmwong

March 20, 2010 at 6:46 pm

Cardiac Perfusion

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Inferior = right coronary
Anteroseptal = LAD
Anteroapical = LAD (distal)
Anterolateral = Circumflex
Posterior = right coronary

Myocardial Perfusion

  • 201-Tl, 99m-Tc Sestamibi, NH3
  • prognostic value
  • protocols
    • 1 day: inject @ rest, image rest, exercise, inject, image stress
    • 2 day: exercise, inject, image stress // inject @ rest, image rest
    • dual isotope: inject Tl @ rest, image rest, exercise, inject sestamibi, image stress
  • Pharmacological Stress Agents
    • Persantine/Dipyridamole: increases serum adenosine by decreasing breakdown; reversed by Aminophylline
    • Adenosine: $$, <10s 1/2 life, side effects (heart block, bradycardia)
    • Dobutamine: adrenergic agonist increases myocardial oxygen demand, inducing ischemia; tritrate up to target HR; reversed by Esmolol drip
  • What to look for
    • reversible ischemia (mismatched defect on stress vs rest)
    • transient ischemic dilation: balanced 3 vessel ischemia; ischemic endocardium makes it look like ventricular dilation
    • LV aneurysm
    • RV prominence
    • Wall motion abnormality
    • LV EF
    • extracardiac activity (ie. tumors!)
  • Fixed defects can be:
    • infarct
    • hybernating myocardium
    • artifact
  • Pitfalls
    • liver can steal counts from myocardium; do delays
    • LBBB gives a false positive in atypical septal/inferior pattern; seen on only dobutamine and exercise; do adenosine

Viability Study

  • Viable Myocardium = “Flow + Metabolism Mismatch”; myocardial blood flow versus glucose utilization

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Written by lmwong

February 2, 2010 at 8:19 am

Reading V/Q scans

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Normal

  • perfusion and ventilation is uniform in both lungs
  • hila, aorta, fissues appear as defects
  • wash out in 2-3 minutes ventilation

Bilateral perfusion defects

  • PE
  • Extrinsic compression of pulmonary artery
  • Physiologic response from decreased or absent ventilation
  • pleural effusion

Unilateral perfusion defects

  • mucus plug
  • compression of pulmonary artery by tumor
  • fibrosing mediastinitis
  • PE
  • massive effusion
  • pneumonitectomy

Ventilation abnormalities

  • Chronic lung disease
  • mucus plug
  • airspace disease

Matched Defect

  • COPD
  • airspace disease
  • tumors and other mass lesions
  • asthma
  • pleural effusion
  • lung infarction

Mismatched defect

  • PE
  • Pulmonary artery compression
  • radiation therapy
  • vasculitis

Reverse mismatched defect

  • pneumonia
  • alveolar pulmonary edema
  • mucus plug

Interpretation and Probability

Modified PIOPED criteria link

Written by lmwong

January 26, 2010 at 9:13 am

Disease and Nuclear Medicine Agent

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CNS

  • Brain death = Tc-99m labelled pertechnetate and DTPA, (sometimes HMPAO, ECD)
  • SPECT brain perfusion = Tc-99m lab. HMPAO and ECD
  • CSF (normal pressure hydrocephalus) = In-111 lab. DTPA

Neck

  • Thyroid = I-123 and 131
  • Parathyroid = Tc-99m lab. sestamibi
  • Salivary Gland = Tc-99m pertechnetate

Cardiovascular

  • Myocardial perfusion = Tc-99m Sestamibi, Thallium-201, Tc-99m Tetrofosmin

Pulmonary

  • PE = Tc-99m MAA perfusion, Xe-133 ventilation

Liver

  • Normal tissue = Tc-99m sulfur colloid
  • Hemangioma = Tc-99m RBC
  • HCC = Gal-67

GI

  • GI bleed = Tc-99m RBC, (Tc-99m colloid)
  • Meckel’s diverticulum = Tc-99m pertechnetate
  • Hepatobiliary/GB = Tc-99m IDA (or HIDA)
  • Gastric or Esophageal motility = Tc-99m colloid
  • Vit B12 malabsorption (Schilling test) = Co-57 Vit B12
  • Carcinoid = Octreotide scan
  • Focal Nodular Hyperplasia = Sulfur Colloid Normal
  • Fibrolamellar Hepatocarcinoma = Sulfur Colloid Cold

MSK

  • Bone Scan = Tc-99m MDP, F-18
  • Osteomyelitis = Tc-99m diphosphoate (3 phase bone scan), Ga-67 citrate, In-111 or Tc-99m lab. WBC.

GU

  • Glomerular filtration = Tc-99m DTPA
  • Tubular excretion = Tc-99m MAG3
  • Parenchyma = Tc-99m-DMSA
  • Acute Pyelonephritis = DMSA
  • Mass = DMSA
  • Vesicoureteral Reflux = pertechnetate, DTPA, sulfur colloid
  • Transplant eval = DTPA or MAG3
  • Scrotum = DTPA
  • Adrenal Cortical = NP-59
  • Adrenal Medullary (Pheo, neuroblastoma) = MIBG

Infection

  • Ga-67 citrate
  • In-111 oxine WBC
  • Tc-99m HMPAO WBC
  • Tc-99m-fanlesomab

Written by lmwong

December 17, 2009 at 10:56 pm

Posted in nuclear medicine

HIDA Scan

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Hepatobiliary IminoDiacetic Acid: actively excreted into hepatocytes, bile canaliculi, biliary radicles, bile duct, gall bladder, and small bowel.

Indications

  • acute cholecystitis
  • chronic cholecystitis
  • assess biliary patency
  • identify biliary leaks
  • differentiate biliary atresia from neonatal hepatitis
  • suspected biliary dyskenesia
  • suspected sphincter of oddi dysfunction

normal

  • activity seen in gallbladder, bile duct, and small bowel within 30 minutes, definitely by 4 hours.
  • CCK given at 30 minutes, contracts gallbladder (faster)

Acute cholecystitis

  • HIDA cannot enter gallbladder through inflamed cystic duct
  • no activity in 4 hours or 30 minutes after morphine
  • no contraction after CCK
  • rim sign
  • cystic duct sign

Chronic cholecystitis

  • delayed imaging of gallbladder
  • delayed emptying after CCK (vs no emptying with acute)
  • Delayed biliary to bowel transit

Biliary dyskenesia

  • normal = >50%
  • borderline = 35-50%
  • dyskenesia = <35%

Written by lmwong

April 13, 2008 at 3:25 pm

Posted in gi, nuclear medicine