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25 Cards in this Set
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Hypertrophic osteoarthropathy
Primary: 3-5%, rare familial AD, pachydermoperiostosis Secondary: associated with bronchogenic carcinoma, mesothelioma, Hodgkin’s Features: periostitis in long bone Precede clinical symptoms (bone pain, arthralgia), regress after treatment (scans normal 1-6 months after) DDX diffuse periostitis Hypertrophic osteoarthropathy Thyroid acropachy (MC hands) Venous stasis Primary hyperparathyroidism Hyperthyroidism Reflex sympathetic dystrophy Hypervitaminosis A Flurorosis Caffey's disease (exuberant hyperostosis) Bone scan Tc-MDP (methylene diphosphonate) Increased activity seen with: Increased osteoid formation (most important) Increased blood flow to hyperemic areas Interruption of sympathetic supply (RSD) Critical organ: bladder (need hydration) 50% fixed to bone by 4 hrs, 70% renal excretion by 24 hrs Dose 20-25 mCi |
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Hodgkin’s lymphoma
Lymphoma: residual disease vs inactive fibrosis Gallium-67: binds to iron transport proteins (transferrin, ferritin, lactoferritin), uptake by leukocytes Normal uptake: liver (hottest), spleen, bone marrow Dose 10 mCi (2x dose used for inflammation or infection) Imaging at 48,72 hrs (6,24 hrs for abscess) Critical organ: bowel Collimator: medium-energy, parallel hole Use laxatives to decrease bowel activity, image may be delayed 4 to 7 days |
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Paget’s disease
Lytic, sclerotic and mixed phases: hot on all 3 phases Features: Cortical thickening, bony expansion Bowing of tibia and femur (shepherd's crook deformity) Early: thickening of iliopubic and ilioischial lines Osteoporosis circumscripta: Lytic phase Frontal bone, outer table destroyed only DDX: Fibrous dysplasia Chronic osteomyelitis Primary bone tumors (osteosarcoma) Malignant degeneration: MC osteosarcoma, fibrosarcoma |
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Prostate cancer
Superscan: increased uptake relative to renal and soft tissue DDX: Metastases: breast, lung, prostate Metabolic: renal osteodystrophy, osteomalacia, hyperparathyroidism Myelofibrosis, systemic mastocytosis |
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Plummer’s disease
Plummer’s disease: hyperthyroidism due to an autonomous hot nodule (ATN, usually hyperfunctioning adenoma) with suppression of the remaining gland Less than 1% of hot nodules represent carcinoma Increased T4/T3, low TSH from suppression Diagnose with I-123: Image 24 hrs (normal uptake 10-30%) Treatment: Surgery or I-131 ablation (20-25 mCi) Post-treatment, hypothyroidism uncommon since uptake preferential to hot nodule, little beta-radiation to rest of gland |
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Cold thyroid nodule
Nonspecific: 75% of cold nodules are secondary to colloid cyst or adenoma, LC nodes, abscess, hematoma Incidence for carcinoma is MC in cold nodules than hot nodules but still low (15-25%) More likely to be benign: Older female patients Multiple nodules Nodule decreases in size while on thyroid hormone Ultrasound: differentiate solid from cystic lesion |
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Pneumocystis carinii pneumonia
Gallium scan: Bilateral and diffuse uptake without mediastinal involvement More focal area of increased gallium uptake in LUL |
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Toxic multinodular goiter
Case findings: I-123 24 hour uptake = 53% (normal 10-30%) Gland of normal size with multiple focal regions of increased activity in both thyroid lobes Patient subsequently underwent I-131 therapy recommended dosage is 20-70 mCi Hyperfunctioning thyroid nodules are the 2nd MC cause of hyperthyroidism (MC Grave’s) |
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Sacral insufficiency fracture
Honda sign on bone scan Stress fracture: Fatigue fracture: repeated stress on normal bone Insufficiency fracture: normal stress is placed on abnormal bone (MC secondary to osteoporosis) |
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Sacral insufficiency fracture
Honda sign on bone scan Stress fracture: Fatigue fracture: repeated stress on normal bone Insufficiency fracture: normal stress is placed on abnormal bone (MC secondary to osteoporosis) |
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Normal pressure hydrocephalus
Persistent ventricular activity Delayed convexity flow Normal CSF flow Spinal (black arrows) and cisternal (white arrows) activity Progressive flow over convexities at 24 and 48 hours Abnormal CSF flow NPH: persistence of ventricular uptake at 24 and 48 hours CSF leak: activity outside neural axis Asymmetry of flow in cisterns or around convexities |
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Initial static images
2 days later |
Brain death
Case findings: No blood flow to supratentorial or infratentorial brain Absent sinuses Absent ICA flow (hot nose sign) Hot nose sign: Nasopharynx uptake: suggests ECA circulation from impeded ICA flow NOT pathognomonic for brain death Brain death: absent cerebral flow despite maintained cardiac and respiratory function Static images after flow show whether tracer is taken up by the cortex Blood flow agents: 99mTc pertechnetate, 99mTc DTPA, 99mTc glucoheptonate Need to show presence of flow above the skull base in arterial phase, AND activity in sinuses (especially superior sagittal sinus and transverse sinus) on delayed venous phase DTPA: no salivary uptake Cross blood-brain barrier and accumulate in the brain: 99mTc HMPAO, 99mTc ECD Flow study NOT required HMPAO: shows salivary uptake, preferred agent (obtain dynamic and static images) |
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Alzheimer’s disease
Decreased perfusion and FDG uptake in bilateral parietal and posterior temporal lobes Sparing of sensorimotor cortex, BG, and thalami, which appear more pronounced |
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Cross cerebellar diaschisis
Case findings: Large perfusion defect in left MCA territory Reduced relative uptake in right cerebellar hemisphere Crossed-cerebellar diaschisis: Seen on PET and SPECT Contralateral cerebellum shows decreased uptake Due to loss of afferent stimuli, may have accompanying cerebellar symptoms that are reversible |
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Myositis ossificans
Case findings: Soft tissue heterotopic bone formation |
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Reflex sympathetic dystrophy (Sudeck's atrophy)
Case findings: Increased periarticular uptake on bone scan XR: generalized regional osteopenia with periarticular osteoporosis, with preservation of joint spaces |
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Colloid shift in cirrhosis
Splenomegaly, nodular liver Increased uptake in bone marrow colloid shift Secondary to decreased colloid sequestration by the liver due to depletion of reticuloendothelial cells from scarring |
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Meckel’s diverticulum
Tracer: 99mTc pertechnetate (taken up and secreted by gastric mucosa) Abnormal uptake should occur at the same time as gastric uptake Enhance sensitivity with: Pentagastrin: increase rapidity, duration, and intensity of uptake Glucagon: decrease peristalsis Cimetidine: histamine antagonist, inhibits secretion of pertechnetate from gastric mucosa Complication: Bleeding: acid and pepsin secretion by gastric mucosa produces ulceration of adjacent bowel mucosa |
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Gastric emptying study
Case findings: Delayed gastric emptying status post Billroth II surgery Tracer: 99mTc sulfur colloid 111-In DTPA can alternatively be used in liquids Indications: diabetic gastroparesis, children with GE reflux Solid meals better at detecting mild to moderate delay in gastric emptying Solid emptying: initial lag (time for antrum to grind up food particles) followed by linear emptying, T1/2 = 1 to 2 hours Liquid emptying: exponential pattern, T1/2 = 30 minutes |
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Choledochal cyst
Type 1: MC, fusiform dilatation of CBD Type 2: diverticulum of CBD Type 3: dilatation of intraduodenal portion of CBD (choledochocele) Type IV: Type IV-a: intrahepatic and extrahepatic ductal dilatation Type IV-b: extrahepatic ductal dilatation Type V: Caroli’s disease (MC intrahepatic ductal dilatation) |
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Inflammatory bowel disease
Abnormal accumulation of leukocytes in colon Most likely ulcerative colitis or pseudomembranous colitis |
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Parathyroid adenoma
Case findings: Increased uptake on 99mTc-sestamibi images in the left inferior parathyroid gland Best appreciated on subtraction images of the 99mTc-sestamibi and 99mTc-pertechnetate Uptake by thyroid and parathyroid: Th-201, sestamibi Uptake ONLY by thyroid: Pertechnetate, iodine-123 Thalium-201 and 99mTc-pertechnetate subtraction Thyroid and parathyroid tissue take up Thalium-201 99mTc-pertechnetate is taken up only by thyroid tissue 99mTc-sestamibi and Iodine-123 subtraction Sestamibi is taken up by both Iodine is taken up only by thyroid tissue 99mTc-sestamibi and 99mTc-pertechnetate subtraction Technique used in this case Only 99mTc-sestamibi (with early and delayed images) Both thyroid and parathyroid tissue take up sestamibi Thyroid tissue will wash out the radiotracer, whereas a parathyroid adenoma will retain it on delayed images |
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Captopril renography
Tracer: DTPA or MAG3 in combination with Captopril DTPA: Decreased excretion with delayed appearance of tracer Measure of GFR MAG3: Prolonged retention of tracer Renally secreted (hippuran analogue) Renal perfusion is disproportionately reduced in a kidney with renal artery stenosis when Captopril is used compared with a standard renal scintigram Captopril: ACE inhibitor, block formation of angiotensin II thus decreasing renal efferent arteriolar pressure and function of the affected kidney |
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Graves’ thyroiditis (early)
Case findings: 24 hours after I-123: Diffuse increased uptake of radionuclide throughout thyroid No discrete hot or cold nodules are identified I-123 uptake 38% (normal 10-35%) Increased uptake with subnormal TSH and normal fT4 and fT3 early Graves' thyroiditis |
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Sarcoidosis
Case findings: Bilateral hilar uptake of FDG DDX of PET FDG findings: Lymphoma FDG PET Benign lesions (infectious and inflammatory processes) with false-positive findings Chronic thyroidosis Warthin’s tumor of the parotid Chronic sinusitis Chest: Sarcoidosis Active tuberculosis, granuloma Thymoma, pneumonia, abscess LC lesions: Thymic hyperplasia Aspergillosis, histoplasmosis Rheumatoid disease, alveolitis Radiation pneumonitis |
