Head and Neck Imaging MCQs

The clinical scenario is suggestive of vitamin A toxicity. Blackbuck's liver should not be consumed to avoid toxicity of vitamin A. Vitamin A and other fat-soluble vitamins are stored particularly in the liver and adipose tissue. Vitamins can be broadly classified into two categories fat-soluble vitamins (A, D, E, K) and water-soluble vitamins (B, C) Reference: Harper's Illustrated Biochemistry, 32nd Edition, Page Number-527.

The clinical syndrome of CNS abnormalities is called HIV-associated neurocognitive disorder (HAND). Microglia, cells in the CNS that belong to the macrophage lineage, are the predominant cell types in the brain that are infected with HIV. It is believed that HIV is carried into the brain by infected T cells or monocytes. The mechanism of HIV-induced damage of the brain remains obscure. Because neurons are not infected by HIV and the extent of neuropathologic changes is less than expected from the severity of neurologic symptoms, most workers believe that the neurologic deficit is caused indirectly by viral products and by soluble factors produced by infected microglia. Reference: Robbins and Cotran Pathologic Basis of Disease, 10 th Edition, Page Number-253.

Calcification: True. Meningiomas can often exhibit calcifications, which can be seen on imaging. Vascular markings: True. Meningiomas can show prominent vascular markings due to their vascularity. Hyperostosis: True. Meningiomas can cause hyperostosis or thickening of adjacent bone due to their slow-growing nature and pressure effect on bone. Drop metastasis: False. Drop metastasis refers to the seeding of tumor cells along the spinal cord or brain surface via the cerebrospinal fluid (CSF), which is not a characteristic feature of meningiomas. It is more commonly associated with medulloblastomas and other tumors that spread through the CSF.

Cranio cervical CTA should also specifically be considered in the setting of penetrating neck injury, if a fractured foramen transversarium or facet subluxation is identified on cervical spine CT, or if a skull base fracture traverses the carotid canal or a dural venous sinus. Arterial laceration or dissection, traumatic pseudoaneurysm, carotid-cavernous fistula, or dural venous sinus injury are nicely depicted on high-resolution CTA. Reference: Osborn Brain edition 2 page number- 7

Because of its wide availability and rapid detection of acute hemorrhage, CT is now accepted as the worldwide screening tool for imaging acute head trauma. CT depicts both bone and soft tissue injuries. It is also widely accessible, fast, effective, and comparatively inexpensive. Reference: Osborn Brain edition 2 page 6

In the fetus, deoxygenated blood is carried to the placenta by the umbilical arteries, which arise from the internal iliac arteries. Oxygenated blood returns from the placenta to the right atrium by way of the umbilical vein, left portal vein, ductus venosus, and inferior vena cava. Flow across the trumpet-shaped ductus venosus produces a defined stream of oxygenated blood that preferentially flows through the foramen ovale to the left atrium, left ventricle, and aorta, diverting the most oxygenated blood to the head and neck vessels and the coronary arteries. The foramen ovale is present in the interatrial septum which allows the blood to flow from right atrium to left atrium. Reference: A Radiologist’s Guide to the Performance and Interpretation of Obstetric Doppler US Anne M. Kennedy and Paula J. Woodward RadioGraphics 2019 39:3,page number 893-910

Fetal femur length (FL) is one of the basic biometric parameters used to assess fetal size. Femur length can be used to calculate fetal length, another predictor of fetal growth. In third trimester the femur length gives an accurate estimation of fetal weight and size.he transducer must be aligned to the long axis of the diaphysis,perpendicular to the beam, with both ends of the ossiied diaphysis appearing squared of. The cursors should be positioned at the junction of the echogenic bone with the hypoechoic cartilage, and the thin, bright relection of the cartilaginous epiphysis should not be included in the measurement. Reference: Diagnostic ultrasound, Carol M. Rumack, Deborah Levine, 5th edition page number 1445

Assessment of gestational age is most accurate in first trimester, as biologic variation in fetal size is minimal. The first structure measured for this purpose is gestational sac. Most authorities use mean sac diameter(MSD) measurement for this purpose, which is the mean of length, width & antero-posterior diameters. The next landmark is yolk sac, the presence of which without an embryo corresponds to 5.5 weeks. Once the embryo becomes visible, measurement of choice becomes crown-rump length, which is the greatest embryonic length measured by placing the calipers at the head & rump of the fetus. Gestational age estimated has a maximal error of 3-7 days. Reference: Ultrasound in obstetrics and gynecology by Dr. P. K. shah, Dr. Mandakini megh, Dr. Nandita palshetkar page number 46