General 2

Question 1

-ve contrasts

Answer 1

Air
Water
Mannitol

They make tissue black

Question 2

+ve contrast

Answer 2

Make tissue white

Question 3

MRI contrast agents(CA)

Answer 3

Gadolinium based
-gadoxetic acid
-gadobenate dimeglumine
(Hepatobiliary specific gd ca )

Given I v
Excreted through kidney and go
In tissues based on vascularity

They dec t1rt so image white
And dec t2rt so image black
And post contest mri is always t1mri

Question 4

MRCP

Answer 4

No dye as water in bile ducts acts as contrast so MRCP is t2wmri

Question 5

Gd CA

Answer 5

Does not cross Bbb
So dura seeen normally
But if leptomeningeal enhancement seen - sign of meningitis

Gd crosses placenta so not in pregnancy

In CKD where GFR <30ml/min Gd causes nephrogenic systemic fibrosis - chronic scleroderma like illness so RFT imp before giving this CA

Question 6

Usg contrast agents

Answer 6

Levobist
Sonoview
Are micro bubbles injected I v
Depend on vascularity of tissue and so used for vascular characterisation

Characterise focal liver lesion
Triphasic scan in HCC

Excreted through lungs

Question 7

Iodinated water soluble contrast agents

Answer 7

Emits iodine so xrays used
Can be:
Ionic monomer (3:2)- urograffin, gastrograffin, ditrizoate HOCM

Ionic dimer(6:2) - ioxoglate LOCM

Non ionic monomer (3:1)- iohexol (omnipeg)LOCM

Non ionic dimer (6:1)- iodioxanol (visiprove) isoosmolar CM

Question 8

ADR of CA

Answer 8

-anaphylactoid reaction (non ige mediated hsn)
Tt is 1:1000 im adrenaline
-contrast induced nephropathy where contrast induced AKI when CA >.5mg/dl
And contrast induced nephropathy when CA >1mg/dl

Happens when rft is compromised, osmaolartiy of CA more and renal excretion of CA is there

Question 9

Mets

Answer 9

CA lung - adrenal for non symptomatic
Brain for symptomatic

Small cell CA - brain
Non small cell CA - adrenal

Question 10

Tt of cin

Answer 10

-hydration of pt
-isoosmolar CA use
-drugs like
N acetyl cysteine (mc)
Theophylline
Na HCO3 (2nd mc)
Ascorbic acid
NOT MANNITOL AND DIURETICS
Haemofiltration is protective and not hameodialysis

Question 11

Renal excretion in

Answer 11

CECT
IVP
CT ANGIO
ANGIOGRAPHY

Question 12

Nuclear scans

Answer 12

Gamma camera has sodium iodide detectors activated by thallium

Energy of gamma rays - 140 kilo e volt
T1/2 of tc- 6hrs

Question 13

Types of nuclear scans

Answer 13

• Tc DTPA- for gfr measurement
• Tc MAG3- for renal function (gfr and tubular secretion measurement)
• Tc DMSA - tells about structure of kidney cortex, if scar present or amount of functioning renal parenchyma
• Tc pertechnate- for gastric mucosa (meckels diverticulum is activity in peri umbilical or right iliac fossa), salivary gland (where it picks up warthins tumor as hot spot) and thyroid

Question 14

Thyroid

Answer 14

I123 used for thyroid scanning where it’s t1/2 is 13 hrs but not present in India so pertechnate scan used
I131- used for thyroid ablation where it’s t1/2 is 8 days

Question 15

Other scans

Answer 15

MIBG - pheochromocytoma
SestaMIBI scan- parathyroid adenoma
HIDA scan - biliary atresia
-gold standard to diagnose acute cholecystitis but IOC Is USG
Selenium methionine scan- for pancreas
MDP- bone scan for osteoblastic activity
Octreotide scan- also cld somatostain receptor scintigraphy used for neuroendocrine tumors

Question 16

Heart

Answer 16

Thallium scan 
-for myocardial perfusion
-reversibility if myocardial ischemia 
-to diff viable and non viable myocardium
Non invasive test for this is FDG PET 

MUGA scan- for ventricular function (where it sees contractility of ventricles ejection fraction)

Question 17

Pet scan

Answer 17

18 FDG (flouro deoxyglucose) where it’s t1/2 is 110min

It competes with glycolysis so it dec as it is metabolised by hexokinase so before performing do blood sugar as dec glucose so hypoglycaemia can occur

Principle of pet- annihilation where positron combines with e and neutral charge and mass is released as energy of 511kev
FDG marker of glycolysis

Question 18

Pet scan activity

Answer 18

Carcinoid and bronchoalveolar CA don’t show activity on it as no glycolysis
Brain and brown fat show inc activity normally so interscapular area and nape of neck show inc acitivity

Glucose metabolism in tumor is by GLUT3 present in brain and placenta normally so brain and brain tumor show same activity but radiation induced necrosis in brain and recurrence can be picked up on pet

Question 19

Inherent soft tissue resolution poor with

Answer 19

Pet so CT-pet used where pet CT >CECT for staging of cancers

Flouro dopa pet - in Parkinsonism and pheochromocytoma

Alphabeta amyloid pet - in Alzheimer’s
Psma pet- in prostate specific membrane ag so in prostate CA

DOTANOC, DOTA TOC and DOTATATE- affinity for somatostatin r so NET used

Question 20

IOC

Answer 20

Acute Sah- NCCT
Diagnose case of acute SAH- angiography (to see cause of SAH)
Acute pancreatitis- serum lipase and amylase
Assess severity of AP- CECT
DIagnose myelomalacia- MRI
Staging lung CA- pet CT > CECT
Pancoast tumor(compress brachial plexus and sympathetic ganglia)- MRI
POtts spine diagnosis- CT guided biopsy
Extent of Potts spine- mri

Question 21

Mc site of epidermoid cyst in Brain

Answer 21

Cp angle

Question 22

Application of MR to imagine done by

Answer 22

Lauterber