AIIMS/ NEET-PG 2017: Radiology MCQs 61-70

Q-61. Cerebral blood flow in an asphyxiated child is best measured by
a) NIRS (Near infrared spectroscopy)
b) PET
c) Radio-nuclide imaging
d) MRI Angiography

Answer: NIRS (Near infrared spectroscopy)
Explanation:
Cerebral blood volume (CBV), its response (CBVR) to changes in arterial carbon dioxide tension, and cerebral blood flow (CBF) were measured using near infrared spectroscopy (NIRS) in 27 term newborn infants with clinical and/or biochemical evidence consistent with perinatal asphyxia.
An increase in CBV on the first day of life is a sensitive predictor of adverse outcome. A reduction in CBVR is almost universally seen following asphyxia, but is not significantly correlated with severity of adverse outcome.

Q-62. C-1 and C-2 can be best visualized by
a) AP view
b) Lateral view
c) Oblique view
d) Odontoid view

Answer: Odontoid view
Explanation:
The most important cervical spine X-ray is the odontoid view for assessment of the cranio-cervical junction.
The most important X-ray is the swimmer’s view for assessment of the C-7 and T-1.

Q-63. Not a radiological finding of papillary necrosis on excretory urogram is
a) Tracks and horns from calyces
b) Ring shadow
c) Increased dense nephrogram
d) Egg in cup appearance

Answer: Increased dense nephrogram
Explanation:
Radiological characteristics of papillary necrosis:
Tracks and horns from calyces
Egg in cup appearance
Ring shadow
Non specific radiological findings:
Clubbing, blunt or truncated calyces

Q-64. Stereotactic radio-surgery uses all modalities except
a) Proton
b) Electron
c) Linear accelerator
d) Gamma knife

Answer: Electron
Explanation:
Stereotactic surgery or stereotaxy is a minimally invasive form of surgical intervention which makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radio-surgery (SRS) etc.
Kinds:
The Gamma knife
Linear accelerator
Proton beam or heavy charged particle radio-surgery

Q-65. Gold standard investigation for recurrent gastrointestinal stromal tumor is
a) MRI
b) MIBG
c) USG
d) PET CT

Answer: PET CT
Explanation:
CT and 18F-FDG PET have comparable sensitivity and positive predictive values in staging malignant recurrent GISTs. However, 18F-FDG PET is superior in predicting early response to therapy.
Therefore, CT or 18F-FDG PET can be performed for initial diagnosis and staging of malignant recurrent GISTs but 18F-FDG PET/CT scan is preferred for evaluation of early response to imatinib mesylate therapy.
Patients who responded to therapy showed normalization of FDG uptake or a decrease in the SUV (standardized uptake value) of lesions.

Q-66. On abdominal ultrasound gall bladder shows diffuse wall thickening with hyper-echoic nodules at neck and comet tail artifacts. The most likely diagnosis will be
a) Adenomyomatosis
b) Adenocarcinoma of gall bladder
c) Xantho-granulomatous cholecystitis
d) Cholesterol crystals

Answer: Adenomyomatosis
Explanation:
Adenomyomatosis of the gallbladder is a hyperplastic cholesterolosis of the gallbladder wall. It is a relatively common and benign condition.
Ultrasound:
Mural thickening (diffuse, focal, annular)
Focal mass is most concerning as it may be difficult to distinguish from gallbladder carcinoma
Comet-tail artifact- echogenic intramural foci from which emanate V-shaped comet tail reverberation artifacts are highly specific for adenomyomatosis, representing the unique acoustic signature of cholesterol crystals within the lumina of Rokitansky-Aschoff sinuses 4.
MRCP:
Mural thickening
Focal sessile mass
Pearl necklace sign (fluid filled intramural diverticula)
Hourglass configuration in annular types

Q-67. Earliest detectable congenital malformation by USG is
a) Spina bifida
b) Cystic hygroma
c) Anencephaly
d) Encephalocele

Answer: Anencephaly (?)
Explanation:
Ultrasound catch about 74% of major birth defects, and possibly a higher number when conducted by a well-trained specialist and that may be higher for some types of unmistakable malformations, such as anencephaly.

Q-68. Regarding CT scan all are true except
a) Radiation dose exposure is directly related to the time of exposure
b) Quality of the radiation generated depends upon voltage
c) Decrease in mA decreases radiation dose exposure significantly in pediatric chest
d) 50% reduction in kVp reduces 50% radiation dose

Ans: 50% reduction in kVp reduces 50% radiation dose
Explanation:
Quantity of exposure is directly proportional to square of kVp.
Thus reducing kVp by 50% would reduce the radiation dose to 25%.

Q-69. Which of these tumors is least radio-sensitive?
a) Ewing’s sarcoma
b) Osteosarcoma
c) Wilm’s tumor
d) Neuroblastoma

Answer: Osteosarcoma
Explanation:
Radio-sensitivity of different tumor:
Highly sensitive:
Lymphoma
Seminoma
Myeloma
Ewings tumor
Wilms tumor
Moderate sensitive:
Small cell Ca of lung
Breast cancer
Basal cell cancer
Medulloblastoma
Teratoma
Ovarian cancer
Relative resistant:
Squamous carcinoma of lung
Hyper-nephroma
Rectal carcinoma
Bladder carcinoma
Soft tissue carcinoma
Carcinoma of cervix
Highly resistant:
Melanoma
Osteosarcoma