RADIOPEDIA

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RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 8:31 pm

RADIOPEDIA
https://radiopaedia.org


https://radiopaedia.org/cases/osteopetrosis-23
Presentation
Clinically asymptomatic, came for general adult medical exam.
Patient Data
AGE: 25 years
GENDER: Male
صورة
Frontal
Generalized increase in bone density with loss of the normal medullary cavity in ribs.
Sandwich appearance to the visualized spine.

Case Discussion
The patient came for for general adult medical exam.

Chest x-ray showed generalized increase in bone density with loss of the normal medullary cavity (lost cortico-medullary differentiation) which was typical for osteopetrosis.

A pelvic x-ray was be requested as additional study for confirmation. Autosomal dominant adult subtype was considered.
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 8:53 pm

https://radiopaedia.org/articles/11-13- ... an?lang=gb
RADIOPEDIA ARTICLES

11-13 w11-13 week antenatal scan is considered a routine investigation advised for the fetal well being as well as
(for early screening in pregnancy (see antenatal screening

It includes multiple components and is highly dependant on the operator. Traditionally three factors are used to calculate the risk of trisomies:

(crown rump length (must be 45 to 84 mm, gestation age 11 weeks 3 days to 13 weeks 6 days*
nuchal translucency*
fetal heart rate*

Additional markers increase the detection rate and reduce the false positive rates:

nasal bone
ductus venosus flow
tricuspid flow
Combining these factors with blood tests (i.e. dual marker) has been reported to achieve nearly 95% detection rate for trisomies.

Apart from the screening protocol, early detection of major anomalies may be possible and the checklist must include the following conditions:

acrania
encephalocele
alobar holoprosencephaly
iniencephaly
body stalk deformity
gastroschisis
omphalocele
limb reduction
megacystis

Quiz questions

Which of the following statement is false regarding 11-13 weeks antenatal scan?

fetal urinary bladder length more than 7 mm increases the risk of trisomy 13/18
none
presence of atrioventricular septal defect increases the risk of trisomy 21
presence of diaphragmatic hernia increases the risk of trisomy 18
presence of holoprosencephaly increases the risk of trisomy 13
with CRL more than 55 mm, if omphalocele is present, it increases the risk of trisomy 13 to 1:10 and trisomy 18 to 1:4 regardless of any other finding.

ANS : none
Explanation
All of the statements are true regarding 11-13 weeks antenatal scan

with CRL <55 mm, omphalocele containing only bowel is not taken into risk calculation for trisomies as this may be physiological herniation, however, if there is liver in the herniated contents, it will increase the risk even with CRL <55 mm
fetal urinary bladder length between 7-15 mm increases the risk of trisomy 13/18 more as compared to the length greater than 15 mm
a diaphragmatic hernia increases the risk of trisomy 18 to 1:4
atrioventricular septal defect increases the risk of trisomy 21 to 1:2
holoprosencephaly increases the risk of trisomy 13 to 1:2

next Q
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 11:02 pm

Early pregnancy
Early pregnancy roughly spans the first ten weeks of the first trimester.

https://radiopaedia.org/articles/early- ... cy?lang=gb

Radiographic features
Antenatal ultrasound

zero - 4.3 weeks: no ultrasound findings

w4.3 - 5 weeks
possible small gestational sac
(possible double decidual sac sign (DDSS
(possible intradecidual sac sign (IDSS

5.1-5.5 weeks:
​gestational sac should be visible by this time

5.5-6.0 weeks
yolk sac should be visible by this time
gestational sac should be ~6 mm in diameter
double bleb sign

more than 6 wks
(fetal pole may be identifiable on endovaginal ultrasound (1-2 mm
fetal heart rate (FHR) should be ~100-115 bpm
gestational sac should be ~10 mm in diameter

6.5 weeks
crown rump length (CRL) should be ~5 mm

7-8 weeks
CRL is between 11-16 mm
cephalad and caudal poles can be identified

8-9 weeks
CRL is between 17-23 mm
limb buds appear
head can be seen as separate from the body

9-10 weeks
CRL is between 23-32 mm
fetal heart rate 170-180 bpm
fetal movement can be seen
a round hypoechoic structure in the fetal brain represents a developing embryonic/fetal rhombencephalon
nuchal translucency may begin to be seen
Transvaginal/endovaginal (TV/EV) scanning
intradecidual sac sign (IDSS): early sign on a TV scan
when the MSD measures 25 mm, an embryo must be visible
when the CRL measures >7 mm, an embryo must show cardiac activity
an embryo should be seen <=14 days after a scan with a gestational sac without a yolk sac
an embryo should be seen <=11 days after a scan with a gestational sac and a yolk sac
Transabdominal (TA) scanning
when the MSD measures 20 mm a yolk sac should be visible
when the MSD measures 25 mm, an embryo must be visible
CT/MRI
Occasionally, early pregnancy is unintentionally imaged by CT or sometimes MRI is done for some concurrent pathology, and its important to know the imaging findings 3.

fluid-filled cystic structure in endometrial cavity (well identified on MRI, and may be visible on CT especially on delayed post-contrast images)
developing placenta seen as curvilinear enhancing structure
fetal pole may be seen in delayed first trimester imaging
corpus luteal cyst may be visible in one of the ovaries
unilocular <3 cm cyst with irregular crenated and enhancing walls

Differential diagnosis to be considered with a positive urinary pregnancy test includes
ectopic pregnancy
missed abortion
gestational trophoblastic disease
If urinary pregnancy test is negative similar findings may suggest submucosal fibroid or retained products of conception.

Practical points
The earlier in pregnancy a scan is performed, the more accurate the age assignment from crown rump length. The initial age assignment should not be revised on subsequent scans 5.

(Overall, the accuracy of sonographic dating in the first trimester is ~5 days (95% confidence range
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 11:13 pm

First trimester of pregnancy

first trimester
ultrasound findings in early pregnancy
gestational sac
(mean sac diameter (MSD
yolk sac
fetal pole
(crown rump length (CRL
confirming intrauterine gestation
double decidual sac sign
intradecidual sign
double bleb sign
(pregnancy of unknown location (PUL
first trimester vaginal bleeding
ectopic pregnancy
pseudogestational sac
decidual cast
tubal ectopic
ampullary
isthmal
fimbrial
atypical ectopic pregnancies
interstitial ectopic
eccentric gestational sac
interstitial line sign
ovarian ectopic
cervical ectopic
scar ectopic
abdominal ectopic
live ectopic pregnancy
heterotopic pregnancy
tubal rupture
failed early pregnancy
(pregnancy of uncertain viability (PUV
miscarriage
threatened miscarriage
irregular gestational sac
missed miscarriage
inevitable miscarriage
incomplete miscarriage
complete miscarriage
anembryonic pregnancy
anembryonic pregnancy in the exam
yolk sac abnormalities
irregular yolk sac
calcified yolk sac
echogenic yolk sac
small yolk sac
large yolk sac
gestational trophoblastic disease
subchorionic haemorrhage
demise of a twin
implantation bleeding
aneuploidy testing
antenatal screening
11-13 weeks antenatal scan
nuchal translucency
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 11:17 pm

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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » السبت مارس 16, 2019 11:24 pm

(1-2-3 one two three rule (ovary

The 1-2-3 rule is a simple aide memoire describing the nomenclature of any small simple anechoic structure in the ovary on ultrasound:

less than 1cm: follicle
1-2cm: dominant follicle
more than 3cm: cyst

https://radiopaedia.org/articles/1-2-3- ... ry?lang=gb
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » الأحد مارس 17, 2019 5:47 pm

rEleven ribs or less is associated with a number of congenital abnormalities and skeletal dysplasias, including:

Down syndrome, Trisomy 21
campomelic dysplasia
kyphomelic dysplasias
(asphyxiating thoracic dysplasia (Jeune syndrome
short rib polydactyly syndromes
trisomy 18
chromosome 1q21.1 deletion syndrome​
atelosteogenesis
spondylocostal dysostosis
spondylometaphyseal dysplasia, Sedaghatain type
Ritscher-Schinzel syndrome

*******

1.5Tesla vs 3.0 T
Comparing 1.5 T vs 3.0 T (1.5 tesla vs 3.0 tesla) MRI systems identifies a number of differences;
a 3 T system has

(increased signal-to-noise ratio (SNR
increased spatial resolution
increased temporal resolution
(increased specific absorption rate (SAR
increased acoustic noise

Signal-to-noise ratio
Theoretically, signal is proportional to the square of the static field strength (B0) whereas noise increases linearly. This implies that, in a perfect system, the signal-to-noise ratio (SNR) of a 3 T system would be twice as good as at 1.5 T. In reality, due to an increase in susceptibility effects in most tissues, the actual improvement is only in the 30-60% range (instead of 100%). With this increased SNR, the spatial resolution and/or acquisition time can be improved, depending on which is more important for the particular case.

Specific absorption rate
Specific absorption rate (SAR) is defined as the amount of radiofrequency energy (joules) deposited in tissues (kg). The limit set by the FDA is an amount which results in an increase of 1-degree centigrade in any tissue 2. SAR is proportional to the static field (B0) squared, meaning that a 3 T system deposits 4 times as much energy within tissue as a 1.5 T system. Additionally, SAR is proportional to

pulse duration and length
pulse number
slice number
flip angle
The dependence of SAR on flip angle results in a relatively large amount of energy deposition for standard spin echo sequences since they use 90-degree flip angles. As a result, there is increased use of gradient echo sequences, which use smaller flip angles. Unfortunately, these latter sequences image T2* and not T2, and are therefore more susceptible to local field artefacts. These problems have largely been overcome with modern units.

Acoustic noise
Rapid gradient switching leads to an increase in the intensity of the acoustic noise, which requires better insulation of both the unit itself and the containing room.

Quiz questions
Changing from a 1.5 Tesla to a 3 Tesla MRI system will:

increase spatial resolution, increase signal-to-noise ratio and decrease temporal resolution
increase spatial resolution, decrease signal-to-noise ratio and decrease temporal resoution
increase spatial resolution, increase signal-to-noise ratio and increase temporal resolution
decrease spatial resolution, increase signal-to-noise ratio and decrease temporal resolution
decrease spatial resolution, decrease signal-to-noise ratio and decrease temporal resoution

https://radiopaedia.org/articles/15-t-vs-30-t?lang=gb

Explanation
see https://radiopaedia.org/articles/15t-vs-3t
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » الأحد مارس 17, 2019 6:06 pm

Physics and Imaging Technology:
MRI

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

****************

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

******************

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- ... el?lang=gb

************

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
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » الأحد مارس 17, 2019 6:17 pm

5th metacarpal pit
https://radiopaedia.org/articles/5th-me ... it?lang=gb
صورة

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.

*************

AAST injury scoring scales
https://radiopaedia.org/articles/aast-i ... es?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.
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Re: RADIOPEDIA

مشاركةبواسطة دكتور كمال سيد » الأحد مارس 17, 2019 7:34 pm

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

https://radiopaedia.org/articles/abc2?lang=gb
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