Physics and Imaging Technology:

Physics and Imaging Technology:
MRI

(MRI (introduction
https://radiopaedia.org/articles/mri-2?lang=gb

20° oblique projection
https://radiopaedia.org/articles/20-oblique-projection?lang=gb

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3-6-9BOWEL RULE
(r3-6-9 Rule (bowel
The 3-6-9 rule is a simple aide memoire describing the normal bowel calibre:

small bowel: <3 cm
large bowel: <6 cm
caecum: <9 cm
Above these dimensions, obstruction should be considered.

https://radiopaedia.org/articles/3-6-9-rule-bowel?lang=gb

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3D ultrasound

Three-dimensional (3D) ultrasound is a technique that converts standard 2D grayscale ultrasound images into a volumetric dataset. The 3D image can then be reviewed retrospectively. The technique was developed for problem-solving (particularly in obstetric/gynaecologic exams) and to potentially reduce the operator dependence of ultrasound imaging.
3D ultrasound in gynaecologic imaging
3D ultrasound has found a useful application in imaging the coronal plane of the uterus. This format has been found to be useful for:

(evaluation of uterine shape abnormalities (e.g. Mullerian duct abnormalities
evaluation of intrauterine device (IUD) location
problem-solving for
(uterine fibroids (particularly % submucosal component
endometrial polyps
intrauterine adhesions

Applications for 3D ultrasound obstetric imaging are also being developed, such as determining gestational sac location if there is a question of interstitial ectopic pregnancy.

3D gynaecologic imaging can be performed with either the transabdominal or endovaginal approach, but the endovaginal approach results in better quality images. The quality of the 3D images depends on the quality of the 2D images.

The "Z-technique" is used in many institutions that practice 3D gynaecologic ultrasound. This technique may be found in detail in reference 2.

Uses of 3D imaging for the uterine adnexa is currently being developed and may have a use in delineating tubal abnormalities, such as hydrosalpinx.

https://radiopaedia.org/articles/3d-ultrasound?lang=gb



5th metacarpal pit https://radiopaedia.org/articles/5th-metacarpal-pit?lang=gb The 5th metacarpal pit refers to the normal exaggeration of the pit-like depression in the head of fifth metacarpal. It should not be mistaken for a fracture (old or new) or an erosion. *********** [size=31]AAST injury scoring scales https://radiopaedia.org/articles/aast-injury-scoring-scales?lang=gb AAST injury scoring scales https://radiopaedia.org/articles/aast-injury-scoring-scales?lang=gb The American Association for the Surgery of Trauma (AAST) injury scoring scales are the most widely accepted and used system of classifying and categorising traumatic injuries. Injury grade reflects severity, guides management, and aids in prognosis. Currently (early 2019), 32 different injury scores are available. Classification The most commonly used injury scoring grades are for the solid viscera: liver kidney spleen pancreas Injury is classified according to either imaging, operative, or pathologic criteria - the highest classification is assigned the final AAST grade 2. Grading of spleen, liver, and kidney injuries has been validated, with increasing grades of injury correlating with increasing mortality, operative rate, and hospitalisation cost 3. Other scales are less commonly used, including: cervical vascular injury chest wall heart lung thoracic vascular injury diaphragm extrahepatic biliary tree oesophagus stomach small bowel colon rectum abdominal vascular injury ureter bladder urethra uterus pregnant non pregnant fallopian tube ovary vagina vulva testis scrotum penis peripheral vascular organ injury History and etymology Early efforts to create organised system for describing and grading traumatic organ injuries included 4 Abbreviated Injury Scale - developed in 1971 in collaboration with the automotive industry to improve vehicle safety, as well as the Injury Severity Score - developed in 1974, first to predict survival Abdominal Trauma Index - developed in 1981, updated for blunt trauma in 1990, organ-specific injury grading, estimating morbidity/mortality In the last 1980s, the AAST formed an Organ Injury Scale (OIS) committee comprising trauma, orthopaedic surgery, urology, and neurosurgery specialists in order to create a more comprehensive classification. The first AAST OIS guidelines published in 1989 classified injuries of spleen, liver, and kidney 5. https://radiopaedia.org/articles/aast-injury-scoring-scales?lang=gb [/size]



AAST liver injury scale https://radiopaedia.org/articles/aast-liver-injury-scale?lang=gb AAST kidney injury scale https://radiopaedia.org/articles/aast-kidney-injury-scale?lang=gb AAST spleen injury scale https://radiopaedia.org/articles/aast-spleen-injury-scale?lang=gb

ABC/2

ABC/2 is a fast and simple method for estimating the volume of intracerebral haemorrhage (or any other ellipsoid lesion for that matter) which does not require volumetric 3D analysis or software. Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus trial eligibility) which is often under-reported 1. It has been well-validated and correlates highly with volumes calculated by planimetric techniques 2,3.

Formula
First described by Kwak et al. 4 and popularised by Kothari et al. 2:

A x B x C / 2
A = greatest haemorrhage diameter in the axial plane
B = haemorrhage diameter at 90º to A in the axial plane
C = originally described as the number of CT slices with haemorrhage multiplied by the slice thickness, but can simply be substituted with the craniocaudal diameter of the haemorrhage where there is access to multiplanar reformats 1
If the measurements are made in centimetres (cm), then the volume will be in cubic centimetres (cm3).

Mathematical basis
The above formula is a simplified version of the formula for the volume of an ellipsoid, which is:

4/3 π x (A/2) x (B/2) x (C/2)
where A, B and C are the three diameters of the ellipsoid
If π is estimated as 3, then the formula can be simplified to ABC/2.

Interpretation
A baseline intracerebral haemorrhage volume of >50-60 mL is a poor prognostic marker 1,5.

Practical points
There are some pitfalls with the ABC/2 method:

assumes an ellipsoid lesion (and thus the more the lesion deviates from this morphology the more inaccurate the calculated volume will be)
overestimates oral anticoagulant-related intracerebral haemorrhage volumes (because they are often
(irregular in shape
an ABC/3 formula has been suggested for these lesions although has not yet been validated
[rtl]https://radiopaedia.org/articles/abc2?lang=gb[/rtl]

Radiology corriculum

https://app.lecturio.com/#/course/c/7596

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