Diagnostic Imaging

CT (Computed Tomography) scanners use X-rays to create cross-sectional images of the body. Multiple X-ray measurements from different angles are processed by computer to generate detailed 3D images. Ultrasound uses sound waves, gamma rays are used in PET scans, and CT definitely uses X-rays, not 'none of these'.

Endogram is a radiograph taken with radiopaque liquid injected into canals.

Wintrobe's method is used for ESR and hematocrit determination, not hemoglobin estimation. Drabkin's method converts hemoglobin to cyanmethemoglobin for colorimetric measurement, Sahli's method uses acid hematin formation, and spectrometry directly measures hemoglobin's light absorption.

Wintrobe's method is used for determining erythrocyte sedimentation rate (ESR) and packed cell volume (hematocrit), not for hemoglobin estimation. Hemoglobin is measured by Drabkin's method (cyanmethemoglobin), Sahli's method (acid hematin), or by spectrophotometry/spectrometry methods.

NCCT (Non-Contrast CT) is the gold standard imaging modality for evaluating chronic sinusitis and recurrent nasal infections. It provides detailed visualization of the bony walls of the paranasal sinuses and identifies mucosal thickening, air-fluid levels, or osteomeatal complex obstruction. Plain X-rays are largely obsolete for this purpose. MRI of the brain is unnecessary as there is no intracranial pathology suggested. Inferior meatus puncture is an outdated diagnostic procedure rarely used today.

The egg-on-side appearance (also called egg-on-its-side sign) is a classic radiological finding in uncorrected transposition of the great arteries (TGA). It results from the abnormal position of the aorta and pulmonary artery on chest X-ray, creating a silhouette that resembles an egg lying on its side rather than standing upright. This sign is specific to TGA and helps differentiate it from other congenital heart diseases.

Hampton's hump is a classic radiological sign of pulmonary embolism, representing a wedge-shaped, pleural-based area of consolidation (infarction) that typically has its base against the pleura and apex pointing toward the hilum. It results from pulmonary infarction when a thrombus occludes a pulmonary artery. The sign typically appears within 12-36 hours after the embolic event and may resolve over weeks. Tuberculosis and bronchogenic carcinoma have different radiological presentations.

Ultrasound comes from a machine that creates an image of the inside of your body. It shows what your baby looks like while still inside your womb (uterus). Ultrasound can tell you many things about your baby, such as:

• How well the baby’s heart works • How well other organs (such as the spine, brain and kidneys) are growing • The anticipated date of birth

Isospora belli is a species of internal parasites. It is responsible for the condition isosporiasis. Autofluorescence aids detection.

MRI technology uses the principles of nuclear magnetic resonance, where hydrogen nuclei in water molecules align with and are disturbed by magnetic fields. This creates signals that computers convert into detailed anatomical images. Electron spin resonance involves electron spins, not nuclei, and diamagnetism is a weak property unrelated to MRI.

Ultrasound has multiple applications: medical diagnosis (imaging organs, tissues), detecting congenital defects in the fetus (prenatal screening), and industrial non-destructive testing (finding cracks/flaws in metal). Since all three uses are valid, 'all of the above' is correct.

 The only microscope that gives 3D' images is scanning electron microscope.

Streptomyces are a non-acid fast genera of Actinimycetes. Streptomyces do not have mycolic acid in their cell walls.

Magnetic Resonance Imaging (MRI) is the modern standard for imaging brain tumors. It uses powerful magnets and radio waves to create detailed images of soft tissues, which is superior to X-rays or ultrasound for brain analysis.

Bacteria have nearly the same refractive index as water, therefore, when they are observed under a microscope they are opaque or nearly invisible to the naked eye. So, different types of staining methods are used to make the cells and their internal structures more visible under the light microscope.