1
Q
What type of waves does Ultrasound (USG) use, and what is its ionizing radiation status?
A
USG uses high-frequency sound waves (2–20 MHz) and is non-ionizing, making it safe in pregnancy.
2
Q
What does CT use, and how is its radiation measured?
A
CT uses X-rays, which are ionizing radiation, and its dose is measured in mSv.
3
Q
What is a key characteristic of MRI, and what is it best for?
A
MRI uses strong magnetic fields, is non-ionizing, and offers the best contrast for soft tissue.
4
Q
In radiology terminology, what is the equivalent of ‘lucent’ in CT, MRI, and USG?
A
In CT, it’s ‘hypodense’; in MRI, it’s ‘hypointense’; and in USG, it’s ‘hypoechoic’.
5
Q
What is the equivalent of ‘opaque’ in CT, MRI, and USG?
A
In CT, it’s ‘hyperdense’; in MRI, it’s ‘hyperintense’; and in USG, it’s ‘hyperechoic’.
6
Q
What is the typical radiation dose for a CXR Skull Xray in mSv?
A
The dose for a CXR Skull Xray is 0.02–0.07 mSv.
7
Q
What is the approximate radiation dose for an Abdomen Xray in mSv?
A
An Abdomen Xray has a dose of approximately 1 mSv.
8
Q
What is the typical radiation dose range for CT head/abdomen in mSv?
A
CT head/abdomen typically has a dose of 2–10 mSv.
9
Q
What is the approximate radiation dose for PET scans in mSv?
A
PET scans have an approximate radiation dose of 10–12 mSv.
10
Q
What is the radiation dose range for Barium meal/enema studies in mSv?
A
Barium meal/enema studies have a radiation dose of 7–8 mSv.
11
Q
What is the radiation dose range for IVP (Intravenous Pyelogram) in mSv?
A
IVP has a radiation dose of 2–3 mSv.
12
Q
According to the ‘Thumb Rule’, when should USG be used?
A
USG should be used in pregnancy and for kidney imaging.
13
Q
According to the ‘Thumb Rule’, when should MRI be used?
A
MRI should be used for soft tissue, neuroimaging, and tumor imaging.
14
Q
According to the ‘Thumb Rule’, when should CT be used?
A
CT should be used for trauma and bone imaging.
15
Q
What type of contrast is used for CT/X-ray, and what are the precautions?
A
Iodinated contrast is used for CT/X-ray. Precautions include checking Renal Function Tests (RFT) and ensuring GFR is greater than 30 ml/min.
16
Q
What is a potential complication of using iodinated contrast in CT/X-ray?
A
A potential complication is contrast nephropathy.
17
Q
What type of contrast is used for MRI, and what is a precaution?
A
Gadolinium contrast is used for MRI. A precaution is for patients with Chronic Kidney Disease (CKD).
18
Q
What is a potential complication of using Gadolinium contrast in MRI?
A
A potential complication is Nephrogenic Fibrosis.
19
Q
What contrast agent is used for USG, and what is a precaution?
A
Sonovue (microbubbles) is used for USG. It is safe in renal failure, with allergy being a rare complication.
20
Q
What contrast agent is used for X-ray GI studies, and what is a precaution?
A
Barium Sulfate is used for X-ray GI studies. A precaution is to avoid it in cases of perforation.
21
Q
What is the mnemonic for remembering contrast agents and their associated modalities?
A
The mnemonic is: Iodine → CT, Gadolinium → MRI, Barium → GI studies, Sonovue → USG bubbles.
22
Q
What does B-mode in USG Doppler show, and what is its key use?
A
B-mode shows anatomy and structure, and its key use is basic organ imaging.
23
Q
What does Color Doppler in USG show, and what are its key uses?
A
Color Doppler shows flow direction and speed, and its key uses include imaging vessels, DVT, and arteries.
24
Q
What does Power Doppler in USG show, and what is its key use?
A
Power Doppler shows flow sensitivity, and its key use is for slow flow and microvessels.
25
What does Duplex mode in USG show, and what is its key use?
Duplex mode shows both B-mode and waveform, and its key use is for peripheral arterial Doppler studies.
26
What does Triplex mode in USG show, and what is its key use?
Triplex mode shows color Doppler and spectral waveform, and its key use is for advanced vessel studies.
27
In USG Color Flow, what does red and blue indicate?
Red indicates flow toward the probe, and blue indicates flow away from the probe.
28
What is the waveform mnemonic for healthy arteries versus veins/DVT?
The mnemonic is: Triphasic = healthy arteries; monophasic = veins/DVT.
29
What are the USG findings that indicate a DVT?
A DVT is indicated by a non-compressible vein and absent flow on Doppler.
30
What is the first test to consider for a pulsatile mass?
The first test to consider for a pulsatile mass is Doppler USG.
31
What is a common characteristic of most contrast agents?
Most contrast agents end in '–ate'.
32
What does 'monomeric' and 'dimeric' refer to in relation to contrast osmolality?
'Monomeric' refers to high osmolality, and 'dimeric' refers to low osmolality.
33
What is the mnemonic for remembering which contrast agents are used for CT and GI studies?
The mnemonic is: Iohexol = CT; Diatrizoate = GI.
34
What is the first-line imaging modality for gallbladder stones, and what is a key sign?
USG is the first-line modality for gallbladder stones, and a key sign is 'shadowing'.
35
What are the typical signs of Acute Cholecystitis on USG?
Signs include RUQ pain, fever, Murphy’s sign, and a thickened gallbladder wall (>3 mm).
36
What is the mnemonic for Acute Cholecystitis?
The mnemonic is MAPH—Murphy, Aching, Pain, Hyperechoic shadow.
37
What are the USG findings for a gallbladder polyp?
A gallbladder polyp typically shows no shadowing and may have a 'comet tail' artifact.
38
What is a Phrygian Cap in the context of the gallbladder?
A Phrygian Cap is a normal anatomical variant where the gallbladder fundus is folded.
39
What is the 'double barrel sign' in the context of obstructive jaundice?
The 'double barrel sign' refers to the visualization of both the portal vein (PV) and the common bile duct (CBD) appearing dilated.
40
What diameter of the CBD is considered indicative of obstruction?
A dilated CBD greater than 6 mm is considered indicative of obstruction.
41
What is the best initial test for obstructive jaundice, and what is the gold standard?
The best initial test is USG, and the gold standard is ERCP (Endoscopic Retrograde Cholangiopancreatography).
42
What does a 'beaded' appearance of the CBD suggest?
A 'beaded' CBD suggests Primary Sclerosing Cholangitis.
43
What is the mnemonic for remembering the significance of a 6mm CBD?
The mnemonic is '6MM CBD—Call for Bil-Dilation'.
44
What is seen on ERCP in Chronic Calcific Pancreatitis?
Chronic Calcific Pancreatitis is characterized by 'chain of lakes' appearance on ERCP, indicating duct irregularity.
45
What is the best radiological investigation for Pheochromocytoma?
MRI is considered the best radiological investigation for Pheochromocytoma.
46
What is Rigler’s triad for Gallstone Ileus?
Rigler’s triad includes Small Bowel Obstruction (SBO), gallstones, and pneumobilia (air in the biliary tree).
47
What is the Hounsfield Unit (HU) range for air?
Air has a Hounsfield Unit (HU) range of -1000.
48
What is the typical appearance of fat on a CT scan based on its HU range?
Fat, with an HU range of -10 to -100, appears dark gray on a CT scan.
49
What is the HU value for water/fluid and why is it significant?
Water/fluid has an HU value of 0. It serves as the neutral baseline and reference standard for the Hounsfield Unit scale.
50
What is the HU range for muscle and how does it appear on CT?
Muscle falls within the 20-30 HU range and appears as light gray on CT scans.
51
How are blood or hemorrhage typically represented on a CT scan in terms of HU and appearance?
Blood/hemorrhage has an HU range of 30-60 and appears gray-white, indicating hyperdensity.
52
What is the HU range for contrast medium and its appearance on CT?
Contrast medium is in the 60-90 HU range and appears white on CT scans, highlighting enhanced vessels and lesions.
53
What is the HU range for bone cortex and its appearance on CT?
Bone cortex has an HU range of 100-300 and appears very white, making it excellent for visualizing fractures and cortical detail.
54
How do metallic objects appear on CT scans and what is their approximate HU value?
Metallic objects appear brightest white on CT scans and have an HU value greater than 1000.
55
What does the mnemonic 'AFFWBCBM' represent in the context of Hounsfield Units?
'AFFWBCBM' stands for Air, Fat, Fluid/Water, Muscle, Blood, Contrast, Bone, Metal, representing substances from darkest to brightest on CT.
56
According to the exam thumb rule, what types of substances are considered hypodense (<0 HU)?
Fat, air, and CSF are considered hypodense (<0 HU).
57
What is considered isodense (0-30 HU) according to the exam thumb rule?
Soft tissue, muscle, and brain are considered isodense (0-30 HU).
58
What substances are classified as hyperdense (>30 HU) based on the exam thumb rule?
Blood, contrast, calcification, and bone are classified as hyperdense (>30 HU).
59
In acute head trauma, what is the typical HU range for a Subdural Hematoma (SDH)?
A Subdural Hematoma (SDH) typically appears hyperdense with an HU range of 30-60 HU.
60
How does an Epidural Hematoma (EDH) appear on CT in terms of density and shape?
An Epidural Hematoma (EDH) appears hyperdense with a lens-shaped appearance, indicating a density greater than 30 HU.
61
Where are Subarachnoid Hemorrhages (SAH) typically visualized on CT?
Subarachnoid Hemorrhages (SAH) are visualized as hyperdense areas within the sulci and basal cisterns.
62
What are common causes of periventricular calcifications seen on CT?
Periventricular calcifications can be associated with CMV and toxoplasmosis (in AIDS).
63
What condition is associated with parenchymal calcifications seen as granulomas on CT?
Tuberculosis is associated with parenchymal calcifications seen as granulomas on CT.
64
Why are gallstones often not visualized on CT, and what is the preferred imaging modality?
Most gallstones are radiolucent on CT and therefore not visualized. Ultrasound (USG) is the best imaging modality for gallstones.
65
What is the primary role of the bone cortex on CT scans?
The bone cortex is hyperdense on CT and is best for fracture detection and visualizing cortical detail.
66
What is an osteoid osteoma and how does it appear on CT?
An osteoid osteoma is a benign bone tumor characterized by a hyperdense nidus (central sclerotic lesion).
67
What is the primary difference in imaging focus between NCCT and CECT?
NCCT (Non-Contrast CT) is primarily used for initial imaging of trauma, hemorrhage, stones, acute stroke, and bone detail, while CECT (Contrast-Enhanced CT) is used for inflammation, tumors, vascular lesions, and organ perfusion.
68
What are the advantages of NCCT compared to CECT?
The advantages of NCCT are that it is fast and carries no risk associated with contrast administration.
69
What are the advantages of CECT compared to NCCT?
The advantages of CECT are better tissue differentiation and lesion characterization.
70
What does the exam mnemonic 'IOC NCCT for CASH' stand for?
'IOC NCCT for CASH' stands for 'In Order to Consider' NCCT for Acute Stroke, Head trauma, Calculi, and Hemorrhage, indicating these conditions benefit from NCCT first.
71
What is the purpose and typical HU range for a Lung Window in CT imaging?
A Lung Window has an HU range of -1200 to -600 and is best for visualizing pulmonary parenchyma, pneumothorax, and nodules.
72
What is the purpose and typical HU range for a Bone Window in CT imaging?
A Bone Window has an HU range of +200 to +2000 and is used for visualizing fractures, cortical detail, and osteolytic/osteosclerotic lesions.
73
What is the purpose and typical HU range for a Soft Tissue/Mediastinal Window in CT imaging?
A Soft Tissue/Mediastinal Window has an HU range of 0-400 and is used for visualizing organs, vessels, and mediastinal masses.
74
What is the purpose and typical HU range for a Brain Window in CT imaging?
A Brain Window has an HU range of 0-100 and is used for differentiating gray matter from white matter.
75
What does a Whole Body CT for trauma typically include?
A Whole Body CT for trauma typically includes CT head (NCCT), C-spine, Chest, Abdomen, Pelvis, and Extremities.
76
Why is a Whole Body CT performed in trauma cases?
It is performed to rule out occult injuries such as solid organ lacerations, pneumothorax, and pelvic fractures.
77
What is the initial imaging modality for head trauma, and why?
NCCT head is the initial imaging modality for head trauma because it is best for detecting acute hemorrhage.
78
What is the primary purpose of performing an NCCT head in suspected acute stroke?
The primary purpose is to rule out hemorrhage, which is a contraindication for thrombolytic therapy.
79
When is MRI generally considered better than CT for imaging acute stroke?
MRI is generally better for imaging ischemia after 6-24 hours, while CT is better for hemorrhage in the hyperacute phase (0-6 hours).
80
What is the initial imaging approach for an acute abdomen, unless peritoneal perforation is suspected?
NCCT abdomen/pelvis is the initial imaging approach, followed by CECT if inflammation or tumor concern exists.
81
What is the recommended protocol and contrast use for suspected pancreatitis?
CECT abdomen with IV contrast, timed for the pancreatic phase (delayed), is recommended for suspected pancreatitis.
82
What is the protocol for imaging a suspected pulmonary embolism?
CTA chest (PE protocol) with a rapid IV contrast bolus during the arterial phase is used for suspected pulmonary embolism.
83
What is the 'Stone protocol' for imaging renal stones?
The 'Stone protocol' involves NCCT abdomen with no contrast, and it can be performed non-emergently.
84
What is the recommended protocol for suspected aortic dissection?
CTA chest/abdomen with a rapid IV contrast bolus, performed in both arterial and venous phases, is recommended for suspected aortic dissection.
85
What are the typical phases of iodinated IV contrast administration in CT?
The typical phases are arterial (20-30 seconds), venous (60-90 seconds), and delayed (5-10 minutes).
86
What is contrast-induced nephropathy (CIN/AKI)?
CIN/AKI is kidney damage that can occur within 48 hours of contrast administration, particularly in patients with renal impairment.
87
What is considered a relative safe cutoff for GFR when administering iodinated IV contrast?
A GFR greater than 30 mL/min is considered a relative safe cutoff, though hydration is still important.
88
What type of contrast medium is preferred for patients with renal impairment?
Iso-osmolar contrast (like Iodixanol) is preferred for patients with renal impairment due to its lowest risk.
89
What does the mnemonic 'Low osmolar = Lower risk; remember 'Iohe' (Iohexol) for CT' refer to?
It refers to the fact that low osmolar contrast media (LOCM) like Iohexol have a lower risk of adverse effects, particularly CIN, compared to high osmolar contrast media (HOCM).
90
What is considered an absolute contraindication to contrast administration?
Absolute contraindications include a previous anaphylaxis to contrast and severe shellfish allergy (though premedication protocols exist).
91
What are some relative contraindications to contrast administration?
Relative contraindications include a GFR between 30-60 (use caution and hydrate), GFR <30 (use iso-osmolar or delay), diabetes with elevated creatinine, and multiple myeloma (due to dehydration risk).
92
What pre-contrast workup is essential before administering contrast?
It is essential to check renal function (creatinine, GFR), hydration status, diabetes, and history of heart failure.
93
How do metallic foreign bodies appear on X-ray or CT?
Metallic foreign bodies are hyperdense and easily seen, though they can cause significant artifact.
94
Under what conditions is glass visible on imaging modalities?
Glass is hyperdense and visible on X-ray, CT, or USG if it is larger than 3mm.
95
What imaging modalities are best for detecting wood or plastic foreign bodies?
Wood and plastic foreign bodies are radiolucent and best detected with MRI or ultrasound, as they are not visible on X-ray.
96
What is the best imaging modality for detecting bone foreign bodies?
Bone foreign bodies are hyperdense and visible on X-ray.
97
Why might fish bone foreign bodies be difficult to detect on plain films?
Fish bones can have variable radiodensity, with some being radiolucent, making them potentially missed on plain films and better visualized with CT, ultrasound, or endoscopy.
98
What does the exam pearl 'Metal + X-ray easy; Non-metal + MRI/USG; Fish bone + Endoscopy' summarize?
It summarizes the best imaging approaches for different types of foreign bodies: metal is easily seen on X-ray, non-metal objects require MRI or USG, and fish bones often benefit from endoscopy.
99
What are the typical presentations of an esophageal foreign body?
Presentations include dysphagia, chest pain, drooling, and refusal to swallow.
100
What is the initial imaging for a suspected esophageal foreign body?
An X-ray (AP and Lateral chest) is the initial imaging to locate the foreign body type.
101
What is the urgency and management for a button battery lodged in the esophagus?
A button battery is an EMERGENCY and must be removed immediately (within 2 hours) due to the risk of alkali liquefactive necrosis.
102
What is the urgency and management for a food bolus in the esophagus?
A food bolus is considered urgent and is typically removed via upper GI endoscopy.
103
What is the management for a blunt coin foreign body in the esophagus?
A blunt coin is semi-urgent, and a 'watch and wait' approach is often used as most pass spontaneously within 2 weeks.
104
What is the urgency and management for a sharp object (like bone or glass) in the esophagus?
Sharp objects are urgent and require endoscopic removal due to the risk of perforation.
105
What is the urgency for removing a beaded or bevelled margin object from the esophagus?
These objects require STAT removal due to the risk of aspiration or perforation.
106
What is the 'Double density sign' on X-ray in the context of esophageal foreign bodies?
The 'Double density sign' on X-ray indicates two batteries stacked on top of each other, suggesting increased density.
107
What is the primary diagnostic and therapeutic tool for esophageal foreign bodies?
Upper GI endoscopy is the primary tool for both diagnosis and therapy of esophageal foreign bodies.
108
What are the typical presentations of an airway foreign body?
Presentations include coughing, choking, wheezing, dyspnea, and stridor.
109
What is the initial imaging for a suspected airway foreign body?
A Chest X-ray (CXR) is the initial imaging, looking for radio-opacity of the foreign body or air trapping on expiration.
110
What is the preferred method for removing acute airway foreign bodies?
Rigid bronchoscopy is the preferred method for removing acute airway foreign bodies, offering better visualization and airway control compared to flexible bronchoscopy.
111
What are the typical presentations of a gastric foreign body?
Presentations can include abdominal pain, nausea, and vomiting, or the patient may be asymptomatic if the object is inert.
112
What is the management approach for inert gastric foreign bodies like coins or plastic?
Inert foreign bodies are typically managed with a 'wait and watch' approach, as they usually pass spontaneously.
113
When is endoscopic removal indicated for a gastric foreign body?
Endoscopic removal is indicated for sharp foreign bodies due to the risk of perforation or hemorrhage.
114
What are the typical presentations of an intestinal foreign body causing small bowel obstruction?
Presentations include abdominal pain, signs of obstruction, and vomiting.
115
What imaging is used to identify the level of obstruction for an intestinal foreign body?
X-ray followed by CT abdomen is used to identify the level of obstruction.
116
When is surgery indicated for an intestinal foreign body?
Surgery is indicated if there is evidence of perforation, peritonitis, or if conservative management fails.
117
What is a critical contraindication for metallic foreign bodies?
Metallic foreign bodies pose a critical contraindication for MRI due to the risk of ferromagnetic acceleration in the magnetic field.
118
What is the initial imaging step for a suspected metallic foreign body, and why?
X-ray is performed first to identify the material. If it's ferromagnetic (iron, steel), only X-ray/CT should be used, not MRI. If non-ferromagnetic (aluminum, copper), MRI may be safe after localization.
119
What does the mnemonic 'Metal = X-ray/CT; No Metal = MRI ok' refer to?
It summarizes the imaging approach: metallic foreign bodies are best evaluated with X-ray or CT, while non-metallic foreign bodies can generally be safely imaged with MRI.
120
What is the first imaging test for an esophageal foreign body?
X-ray
121
If an esophageal foreign body is radiolucent, what is the next imaging step?
Endoscopy
122
What is the definitive treatment for an esophageal foreign body?
Upper GI endoscopy removal
123
What is the first imaging test for an airway foreign body?
CXR (Chest X-ray)
124
What is the definitive treatment for an airway foreign body?
Rigid bronchoscope removal
125
What is the first imaging test for a gastric foreign body?
X-ray (KUB - Kidneys, Ureters, Bladder)
126
If a gastric foreign body is unclear on X-ray, what is the next imaging step?
CT scan
127
What is the definitive treatment for a sharp or acute gastric foreign body?
Endoscopy
128
How does a coin appear on an X-ray when it's a foreign body?
Circular hyperdense object
129
What is the characteristic sign of a battery foreign body on X-ray?
"Double density" sign (double-walled appearance)
130
How do shards or glass appear on X-ray as foreign bodies?
Small hyperdense fragments
131
How does wood appear on CT/MRI when it's a radiolucent foreign body?
Hypodense, may show streaking artifact
132
How does plastic appear on CT/MRI when it's a radiolucent foreign body?
Hypodense, variable appearance
133
What is the typical density of a food bolus on CT/MRI as a radiolucent foreign body?
Variable density (mixed)
134
What does the Hounsfield Unit mnemonic 'AFFWBCBM' stand for?
Air, Fat, Fluid/Water, Muscle, Blood, Contrast, Bone, Metal
135
What is the Hounsfield Unit for Air?
-1000 HU
136
What is the Hounsfield Unit range for Fat?
-10 to -100 HU
137
What is the Hounsfield Unit for Fluid/Water?
0 HU
138
What is the Hounsfield Unit range for Muscle?
20-30 HU
139
What is the Hounsfield Unit range for Blood?
30-60 HU
140
What is the Hounsfield Unit range for Contrast?
60-90 HU
141
What is the Hounsfield Unit range for Bone?
100-300 HU
142
What is the Hounsfield Unit for Metal?
>1000 HU
143
What does the CT Protocol IOC mnemonic 'NCCT for CASH' stand for?
Calculi, Acute hemorrhage/stroke, Stones, Head trauma
144
What is the immediate management for a button battery foreign body?
EMERGENCY (2 hours)
145
What imaging is recommended for metallic foreign bodies?
X-ray/CT (NO MRI)
146
What imaging is recommended for radiolucent foreign bodies?
Endoscopy/MRI
147
What does 'AVD' stand for in the context of CECT phases?
Arterial, Venous, Delayed
148
What is the arterial phase timing for CECT?
20-30 seconds
149
What is the venous phase timing for CECT?
60-90 seconds
150
What is the delayed phase timing for CECT?
5-10 minutes
151
What is the contrast safety guideline for a GFR > 30?
Safe
152
What is the contrast safety guideline for a GFR between 30-60?
Caution + hydrate
153
What is the contrast safety guideline for a GFR < 30?
Iso-osmolar or delay
154
What does Hounsfield Unit represent?
CT density scale based on water (0 HU)
155
What conditions is NCCT (Non-Contrast CT) best for?
Hemorrhage, calculi, acute stroke, trauma
156
What conditions is CECT (Contrast-Enhanced CT) best for?
Inflammation, tumor characterization, vascular lesions
157
What is the recommended timeframe for endoscopy removal of a button battery in the esophagus?
STAT endoscopy removal (<2 hours)
158
Why should MRI be avoided with metallic foreign bodies?
Ferromagnetic acceleration risk
159
What imaging can be used for small glass foreign bodies (<3mm) that may not show on X-ray?
CT or ultrasound
160
When should creatinine be monitored after contrast administration to assess for contrast-induced nephropathy?
In 48-72 hours post-contrast
161
What is a common radiolucent foreign body that may require endoscopy and high suspicion for diagnosis?
Fish bone
Radio diagnosis
flashcards
Decks in class (21)
# Cards
-
basics and usg abdo184
-
usg abdo 2123
-
usg abdo 3156
-
machines161
-
MRI150
-
mri and c270
-
usg145
-
contrast media78
-
GI131
-
Intestine156
-
gallbladder117
-
gallbladder 232
-
Kidneysss158
-
Uretheral trauma ovaries and pregnancy130
-
thoracic radio210
-
thoracic park 2108
-
neuroradio139
-
neuroradio 296
-
MSK145
-
nuclear radio155
-
nuclear radio 2119
