Ultrasound Principles and Probes

Ultrasound uses the principle of pulse-echo, where sound waves are emitted and reflected back to the transducer. The time it takes for the sound to return determines the distance of the object.

Ultrasound is a medical imaging technique that uses high-frequency sound waves to create real-time images of internal organs and tissues.

A transducer, often made of lead zirconate titanate (PZT), generates sound waves and receives the echoes. It's like a microphone and speaker combined.

Ultrasound waves travel through human tissue at an approximate speed of 1540 m/s. This information is used to calculate the depth of structures.

A linear probe is ideal for imaging superficial structures like the thyroid or carotid arteries, providing high resolution images. Curvilinear probes are used for deeper structures like the abdomen and are good for penetration. Endocavitary probes are used for specific body cavities.

A nationally recognized radiology educator who is the director of Arise Medical Academy, a program that prepares foreign medical graduates for careers in medicine.

Dr. Khaleel Ahmed's expertise in radiology and commitment to training medical students have made him a prominent figure in the field.

Arise Medical Academy is a program that trains foreign medical graduates for careers in medicine, with a particular focus on preparing them for exams like NEETPG, INICET, NEXT, and FMGE.

Dr. Khaleel Ahmed's work at Arise Medical Academy has contributed to the success of many foreign medical graduates.

Foreign medical graduates who go through Arise Medical Academy's rigorous training are prepared to excel in the world of medicine.

USG is the initial investigation of choice in many abdominal conditions, especially when there's suspicion of fluid build-up or organ abnormalities.

USG is the best tool to visualize various fluid collections, such as pericardial effusion, pleural effusion, ascites, and hemoperitoneum, helping diagnose underlying causes.

USG is highly effective in diagnosing most Gallbladder pathologies like acute and chronic cholecystitis, polyps, and stones, but not cancers or emphysematous cholecystitis.

Duplex USG is a specialized ultrasound technique providing detailed information about blood flow. It is crucial in various conditions like varicose veins, varicocele, DVT, portal hypertension, vasa previa & testicular/ovarian torsion.

Color Doppler is a technique that uses color-coding to visualize blood flow direction and velocity. Red represents flow towards the probe, blue represents flow away, and color intensity reflects the flow velocity.

A posterior acoustic shadow is a dark area behind a dense structure, like a renal calculus, preventing sound waves from penetrating further.

Endoscopic ultrasound (EUS) uses high-frequency sound waves to visualize the gut wall layers, allowing for detailed evaluation of structures adjacent to the digestive tract.

The amount of radiation that has been absorbed by a specific object or tissue.

The absorbed dose multiplied by a quality factor that accounts for the type of radiation's biological effectiveness.

The equivalent dose to the whole body that is weighted for the sensitivity of each organ.

A unit of measurement for the rate of radioactive decay, like one disintegration per second.

A device used to measure radiation exposure in occupational workers. It's made of materials like LiF or CaSO4:Dy and worn under a lead apron.

A principle of radiation safety that emphasizes keeping exposure as low as reasonably achievable.

A standard for exchanging medical images and related information between different systems.

A system for storing, retrieving, and distributing medical images, often used in hospitals.

A portable ultrasound device that can be used at the point of care, especially in emergency situations.

A rapid use of ultrasound in patients presenting with shock or hypotension.

A set of symptoms that occur within a few days of exposure to high levels of radiation.

A stage of Acute Radiation Syndrome where the body's immune system is severely weakened.

A stage of Acute Radiation Syndrome where the digestive system suffers severe damage.

The most severe stage of Acute Radiation Syndrome that affects the central nervous system.

A medical imaging technique that uses low-dose X-rays to measure bone mineral density.

Compton scattering is the primary source of scatter radiation in diagnostic radiology, where X-rays interact with electrons, causing a change in direction and energy of the X-ray photon.

Characteristic radiation is the main source of X-ray generation in mammography. It occurs when an electron from the X-ray tube knocks out an inner-shell electron of a target atom, leading to the emission of an X-ray photon with a specific energy.

CT scans use X-rays to create cross-sectional images of the body by measuring the attenuation of the X-ray beam through different tissues.

Hounsfield Units (HU) are a measurement scale used in CT scans to quantify the density of different tissues. Water has a reference value of 0 HU, while denser materials have higher HU values.

In CT scans, cortical bones appear white (hyperdense) because they have high electron density. Fat appears black (hypodense) because it has lower electron density.

CT urography is a CT scan procedure that uses contrast dye to visualize the urinary system, showing structures like kidneys, ureters, bladder, and urethra.

MR urography is a type of MRI scan that uses contrast dye to visualize the urinary system, offering better soft tissue detail than CT urography.

The double density sign on CT pneumothorax refers to the presence of two distinct densities, a dark area representing the air in the pneumothorax and a white area representing the compressed lung tissue.

The Holman-Miller sign, also known as the antral sign, is seen in CT scans of the maxillary sinus. It refers to the anterior bowing of the posterior wall of the maxillary sinus, often seen in adolescent males with epistaxis (nosebleeds).

Computed tomography angiography (CTA) is a CT scan technique that uses contrast dye to visualize blood vessels. It is often used to diagnose conditions like pulmonary embolism (PE) and aortic dissection.

A horseshoe kidney is a congenital anomaly in which both kidneys are fused together at their lower poles. The fusion occurs during fetal development.

A Pelvic kidney is a congenital anomaly in which one kidney is located in the pelvis instead of its normal position in the abdomen. This can happen due to improper migration of the kidney during fetal development.

A Duplex kidney is a congenital anomaly where a single kidney has two ureters and two separate collecting systems. It means there are two distinct renal pelves and two ureters.

A Crossed ectopic kidney is a condition where one kidney is located on the opposite side of the body from the normal kidney. The kidney may fuse with the ipsilateral kidney or be unfused.

Weigert-Meyer rule describes the relationship between ureteral insertion sites in a duplex kidney and their susceptibility to complications. The superior ureter is usually narrow and inserts in the bladder at a lower position, which puts it at risk of obstruction and ureterocele. The inferior ureter is normally wider and inserts at the normal position in the bladder. It may be predisposed to reflux.

A ‘Maiden waist’ deformity on an IVP (Intravenous Pyelogram) refers to a constriction in the middle of the ureter (midureter) that appears as a narrow segment with a slight dilation on either side. It can be commonly seen in patients with tuberculosis.

A ‘Reverse J’ or ‘fish hook’ appearance of the right ureter on an IVP indicates a condition where the right ureter bends sharply near the bladder, resembling a fish hook. This typically occurs due to an obstruction or narrowing near the ureterovesical junction and can be caused by benign prostatic hyperplasia (BPH) or urethral strictures.

Popcorn calcification on pelvic radiograph or iliac bone can indicate a condition involving deposition of calcium in these areas. It is specifically linked with certain diseases such as postmenopausal osteoporosis or metastatic disease.

A thimble bladder is a condition in which the bladder appears small and contracted, resembling a thimble. This is usually caused by tuberculosis infection of the bladder, which leads to scarring and fibrosis of the bladder wall.

A 'Molar Tooth sign' is seen on cystography and indicates a contrast extravasation in the perineum with two distinct lobes forming a shape reminiscent of a molar tooth. This is a sign of posterior urethral valve (PUV) syndrome, a congenital anomaly of the male urethra.

Air trapped in the mediastinum, the space between the lungs, caused by a tear in the esophagus.

A sign seen on an X-ray where the mediastinal air is present, resembling the letter 'V'.

Air trapped under the right hemidiaphragm, often caused by a tear in the intestines.

A sign seen on an X-ray where air trapped under the right hemidiaphragm can mimic pneumoperitoneum (though it's not actually air).

A type of lung infection that can cause a bulging fissure sign, a characteristic feature on an X-ray.

A type of lung infection that typically causes fever, rapid breathing, and a dry cough.

A type of lung infection that can cause a characteristic pattern on CT scans, resembling a 'galaxy'.

Small, scattered opacities (shadows) on an X-ray, often seen in many conditions like TB, mitral stenosis, and sarcoidosis.

Small, scattered opacities on an X-ray, a common sign of miliary tuberculosis.

A type of fungal infection that can cause a 'halo sign' on CT scans.

A type of lung infection that can cause a 'tram track' appearance on CT scans.

Circular opacities (shadows) on an X-ray, often indicating the presence of cancer that has spread to the lungs.

A type of cyst caused by the Echinococcus parasite, often found in the lungs and liver.

A type of mass in the lung, often associated with squamous cell carcinoma, that often has a 'crazy pavement' appearance on CT scans.

A type of lung disease that can cause a 'mosaic attenuation' pattern on CT scans, often seen in people exposed to dust or organic material.