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16 results found

X-linked Opitz G/BBB syndrome

X-linked Opitz G/BBB syndrome (XLOS) is an x-linked disorder with a spectrum of congenital anomalies. Anomalies that may be seen are: facial anomalies  ocular hypertelorism prominent forehead widow's peak broad nasal bridge anteverted nares cleft lip and/or palate  laryngotracheoesophage...

X-marks-the-spot sign (large bowel volvulus)

The X-marks-the-spot is a sign of complete bowel volvulus and refers to the crossing loops of the bowel at the site of the transition. It has been reported to improve diagnostic confidence in detecting caecal and sigmoid volvulus. This is in contrast to the split-wall sign which indicates partia...

X-ray artifacts

Artifacts can present in a variety of ways including abnormal shadow noted on a radiograph or degraded image quality and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts.  There are common and distinct artifacts for film, comp...

X-ray film

X-ray film displays the radiographic image and consists of emulsion (single or double) of silver halide (AgBr is most common) which when exposed to light, produces silver ion (Ag+) and electron. The electrons get attached to the sensitivity specks and attract the silver ion. Subsequently, the si...

X-ray interaction with matter

X-rays in the diagnostic range interact with matter primarily via two processes, which are fundamental in understanding how an image is formed in a radiographic exam. These process are the photoelectric effect  Compton scatter 

X-ray production

X-rays are produced due to sudden deceleration of fast moving electrons when they collide and interact with the target anode. In this process of deceleration, more than 99% of the electron energy is converted into heat and less than 1% of energy is converted into X-rays. Definitions Cathode T...

X-ray tube

An X-ray tube functions as a specific energy converter, receiving the electrical energy and converting it into two other forms of energy: x-radiation and heat. Heat is considered the undesirable product of this conversion process; therefore X-radiation is created by taking the energy from the el...


X-rays represent a form of electromagnetic radiation. They are produced by the x-ray tube, using the high voltage to accelerate the electrons produced by the cathode. The produced electrons interact with the anode, thus producing x-rays. The x-rays produced include Bremsstrahlung and the charact...

Xanthogranulomatous cholecystitis

Xanthogranulomatous cholecystitis is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterised by presence of multiple intramural nodules. Epidemiology It is seen predominantly in female ...

Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis and represents a chronic granulomatous disease resulting in a non-functioning kidney. Radiographic features are usually specific. Epidemiology Xanthogranulomatous pyelonephritis is seen essentially in all age gro...

Xanthomatous meningioma

Xanthomatous meningiomas are rare histological variants of meningiomas grouped into the subtype of metaplastic meningiomas, being WHO grade I tumours. They are characterised by cells with a lipid-filled vacuolated cytoplasm. Although reported numbers are too small to confirm that this is defini...

XCCL view

An XCCL view is a supplementary mammographic view. It is a type of exaggerated cranio-caudal view. It is particularly good for imaging the lateral aspect of the breast.  It is often done when a lesion is suspected on a MLO view but cannot be seen on the CC view. In this view, the lateral aspect...

XCCM view

An XCCM view is a supplementary mammographic view. It is a type of exaggerated cranio-caudal view. It is particularly good for imaging the medial portion of the breast. In this view, the medial portion of the breast is placed forward. A negative 15° tube tilt is suggested. An optimal XCCM view ...


Xenon-127 is a radiopharmaceutical principally used when a performing VQ scan. It is an not widely used alternative to xenon-133 with the main advantage being a higher proton energy allowing for post perfusion scanning.  photon energy: 203 KeV physical half life: 36.3 days


Xenon-133 is a radiopharmaceutical principally used when a performing VQ scan. Inhalation of this gas can also be used to assess cerebral blood flow. photon energy: 81 KeV physical half-life: 5.27 days biological half-life: 30 seconds normal distribution: lungs <15% of inhaled gas is absorb...


The xiphisternum (also known as the xiphoid process or simply the xiphoid) is the smallest of the three parts of the sternum (manubrium, body or gladiolus and xiphisternum). It arises from the inferior and posterior margin of the sternal body and projects inferiorly. It is a small cartilaginous ...

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