Nuclear Medicine Gamuts

      Leonardo

      Double-click → opens on left screen
      Shift & double-click → opens on right screen

      Brain

      Tc-99m pertechnetate-HMPAO, Tc-99m ECD, N-13-ammonia (PET) are perfusion agents, lipophilic & extracted on first pass.

      Diamox → vasodilation of Nl areas → worsened perfusion in areas of vascular dz.

      Tl-201, F-18-FDG (PET) are metabolic agents with activity in tumors but not in areas of radiation necrosis.

      Indium-111-DTPA intrathecally for CSF leak or NPH.

      Multiple, asymmetric cortical perfusion defects Multi-infarct dementia, vasculitis, coccaine abuse
      Symmetrical ↓ activity in posterior parietal-temporal lobes; preserved activity in calcarine cortex & basal ganglia Alzheimer's dz (not specific)
      ↑ activity temporal lobe Herpes encephalitis
      ↑ perfusion & ↑ metabolism during seizure; ↓ or Nl activity interictally Seizure focus
      Lack of intrathecally-administered Indium-111-DTPA activity superior surface of brain after 1-2 days Indicates NPH

      Thyroid

      Tc-99m pertechnetate IV trapped
      Radio-iodine, e.g. I-123 PO trapped & organified

      Discordant nodule: Some Ca are hot using Tc-99m pertechnetate & cold using I-123.

      Thyrotoxicosis

      Condition %RAIU Scan
      Grave's dz ↑ Enlarged, homogeneous
      Toxic multinodular goitre
      (Plummer's dz)       		hi Nl or ↑ Hyperfunctioning nodules,
      suppressed extra-nodular tissue
      Hashitoxicosis (rare, transient)
      (chronic thyroiditis)
      (lymphocytic infiltn)       		↑ Enlarged, patchy
      Toxic nodule (adenoma) usu. Nl Hyperfunctioning nodule,
      suppressed extra-nodular tissue
      Subacute thyroiditis
      E.g. de Quervain's (granulomatous) thyroiditis,
      silent thyroiditis,
      post-partum thyroiditis
      		 ↓ Nonvisualization
      Struma ovarii
      (functioning thyroid tissue in ovarian teratoma)
      ↓
      ↓
      ↓

      GI

      Hepatobiliary

      Tc-99m IDA (e.g. DISIDA) is excreted by hepatocytes, but not conjugated.

      indicates
      Non-visualization of GB at 4 hrs
      or after morphine at 1 hr       		likely acute cholecystitis
      rim sign may be gangrene, rupture, abscess
      Non-visualization of GB at 1 hr
      but visualization at 4 hrs or after morphine       		likely chronic cholecystitis
      Persistent cardiac blood pool activity, poor liver activity, & no biliary excretion hepatocellular disease (e.g. hepatitis, cirrhosis); severe biliary obstruction
      No bowel activity by 1 hr Common duct calculus, tumor, stricture, morphine, sphincter dyskinesia, chronic cholecystitis
      Only liver activity & no cardiac, biliary , or bowel activity may be "liver scan of complete biliary obstruction"
      In neonate, no bowel activity by 24 hrs biliary atresia, severe hepatitis
      CCK ejection fraction > 50% normal
      35 - 50% borderline
      <35% abnormal - sugg acute or chronic cholecystitis

      Colloid Liver-Spleen

      Tc-99m sulfur colloid

      Colloid shift: BM easily visualized; spleen activity > liver Hepatocellular disease ( also look for ascites, hepatoma (photopenic))
      Photopenic lesions Anything that not have reticuloendothelial activity
      (e.g. liver: cyst, hematoma, abscess, fatty infiltration, adenoma, hepatoma, mets
      e.g. spleen: cyst, tumor, infarct)
      ↑ activity FNH, regenerating nodule in cirrhosis, flow abnls

      Meckel's Diverticulum Imaging

      Tc-99m pertechnetate (concentrates in gastric mucosa, in stomach or ectopic)

      Pentagastrin → ↑ mucosal uptake of Tc-99m pertechnetate

      Cimetidine → block release of Tc-99m pertechnetate from mucosa

      Glucagon → ↓ small bowel motility

      GI Bleeding Study

      Tc-99m-labelled RBC's (Tc-99m sulphur colloid only if active bleeding)

      GU

      Kidneys

      Tc-99m-DTPA: GFR
      Tc-99m-DMSA: renal cortex
      Tc-99m-MAG3: tubular agent
      Tc-99m-glucoheptonate: renal cortex & collecting system
      Tc-99m-MAG3 → delayed clearance with signif cortical retention Renal artery stenosis
      Tc-99m-MAG3 → bilateral delayed clearance with signif cortical retention Bilateral renal artery stenosis, obstruction, medical renal dz, pre-renal azotemia
      Tc-99m-MAG3 or DTPA → delayed clearance (20 - 30 mins) with dilated intrarenal collecting system Flaccid system or obstruction. If furosemide → rapid washout, then probab flaccid system.
      Tc-99m-MAG3 → Nl perfusion, ↑'g cortical activity, ↑'g renograms ATN, cyclosporin toxicity
      Tc-99m-MAG3 → absent perfusion Hyperacute rejection (< 24 hrs post-transplantn)
      Tc-99m-MAG3 → poor perfusion, poor excretion Acute rejection (2 -3 mos post-transplantn)

      Testes

      Diffusely hot Epididymitis
      ↓ or absent testicular flow Torsion

      Adrenal

      NP-59 → unilateral adrenal cortical uptake Usu adenoma
      NP-59 → bilateral adrenal cortical uptake Usu hyperplasia
      MIBG → tissue localization pheochromocytoma, neuroblastoma, paraganglioma, carcinoid, medullary thyroid Ca

      Respiratory

      Modified PIOPED Criteria

      Probability Criteria
      High (> 80%) >= 2 large mismatched segmental perfusion defects or the arithmetic equivalent
      Intermediate (20% - 80%) One moderate to < two large mismatched perfusion defects or the arithmetic equivalent
      Single-matched ventilation-perfusion defect with a clear chest radiograph is borderline for low probability
      Difficult to categorize as low or high
      Low (<20%) Nonsegmental perfusion defects (e.g.cardiomegaly, enlarged aorta, enlarged hila, elevated diaphragm)
      Any perfusion defect with a substantially larger chest radiographic abnormality
      Perfusion defects matched by ventilation abnormality provided that there are: a) clear chest radiograph; and b) some areas of normal perfusion in the lungs
      Stripe sign
      Any number of small perfusion defects with a normal chest radiograph
      Very Low <= 3 small perfusion defects ("rat bites")
      Normal No perfusion defects or perfusion exactly outlines the shape of the lung seen on the chest radiograph

      Segmental perfusion defects:
      Large = >75%
      Moderate = 25% - 75%
      Small = <25%

      NM Dictations