Items tagged “refs link”

13 results found
Article

Dural venous sinuses

Dural venous sinuses are venous channels located intracranially between the two layers of the dura mater (endosteal layer and meningeal layer) and can be conceptualised as trapped epidural veins. Unlike other veins in the body, they run alone and not parallel to arteries. Furthermore, they are v...
Article

Reid index

Reid index is a pathological measurement of mucosal gland proliferation in chronic bronchitis. It is assessed by comparing the thickness of the mucous glandular tissue versus the distance from epithelium to the level of cartilage. An index of < 0.4 is considered to be within normal limits.
Article

Hepatic arterial resistive index

The resistive index (RI) is the most common Doppler parameter used for hepatic arterial evaluation. The usual range in normal, as well as post-transplant individuals, is between 0.55 and 0.8. It is measured by: Resistive index (RI) = (peak systolic velocity - end-diastolic velocity)/peak systo...
Article

Pediatric cardiovascular procedures

A number of pediatric cardiovascular procedures are encountered when reporting pediatric imaging. They include: Blalock-Taussig (BT) shunt classic: end to side subclavian to ipsilateral pulmonary arterial anastomosis modified: graft anastomosis Waterston shunt Sano shunt: right ventricle to...
Article

Disappearing basal ganglia sign

The disappearing basal ganglia sign is one of the early signs of a middle cerebral artery (MCA) infarction. It is defined as the loss of delineation of the basal ganglia, due to blurring of their grey-white matter interface and hypoattenuation, consequent to cytotoxic edema at the time of an isc...
Article

Eggshell calcification (breast)

Eggshell calcifications in the breast are benign peripheral rim-like calcifications. Pathology They are typically secondary to fat necrosis or calcification of oil cysts. Radiographic features thin rim-like calcification (<1 mm in thickness) lucent centers small to several centimeters in d...
Article

Isolated greater trochanteric fracture

Greater trochanteric fractures generally result from forceful muscle contraction of a fixed limb, which usually occurs in those who are young and physically active. It can also be caused by direct trauma. Epidemiology Generally, isolated trochanteric fractures are seen more so in young, active...
Article

Endometrium

The endometrium refers to the inner lining of the uterine lumen, composed of endometrial glands surrounded by loose highly cellular connective tissue. Gross anatomy Layers In women of reproductive age, the endometrium is composed of two layers: stratum basale (basal layer): describes the de...
Article

Sinus of Morgagni

The sinus of Morgagni is a defect in the anterior aspect of the pharyngobasilar fascia. It transmits the Eustachian tube and levator veli palatini muscle and allows communication between the nasopharynx and middle ear. Terminology Not to be confused with the foramen of Morgagni, an anterior th...
Article

Fluorography

Fluorography is the use of relatively intense (50-1000mA), pulsed x-ray exposures (pulses are of short duration and applied at 1-12 pulses/second) to form an x-ray image.  The resultant images have a relatively high signal to noise ratio (SNR), i.e the images are of better quality than those ac...
Article

Walch classification of glenoid morphology

The Walch classification of glenoid morphology in primary glenohumeral osteoarthritis is the most commonly used system to describe this pathology.  It was initially measured on 5 mm thick slices on axial CT scans of the shoulder 1, which had mixed results for inter- and intra-observer agreement...
Article

Collimator (Gamma camera)

The collimator of a Gamma camera used in nuclear medicine differs in structure and function to the beam collimators used in general radiography. They typically consist of a lead disc drilled with tens of thousands of closely packed holes, separated from each other by septa. Each hole only acce...
Article

Field of view

Field of view in general corresponds to the area observed or measured out of the possible observable area in the physical world. A field of view will therefore be specified in spatial measurements e.g. millimeters. In radiology, the acquisition or scanning field of view comes closest to this co...

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