peds Flashcards
schizencephaly
CSF fluid filled clefts in the grey matter leading from the ventricles to the surface of the cortex; lined by GM.
may be bilateral in up to 50%
- open or closed.
- polymicrogyria
relationship between SNR and voxel size?
linear -> SNR increases with voxel volume.
SNR increases by sqrt of measurements (# phase encoding steps, # excitations) and decreases with sqrt of receive bandwidth
effect of decreasing matrix size and increasing slice thickness on voxel size and SNR?
increase voxel volume and SNR
Imaging time for a single slice is ?
TR x number of phase encoding steps x averages or number of excitations.
decreasing matrix size in phase encoding direction will also affect imaging time for a single slice how?
decrease time
pediatric UTI - % with duplication?
quoted as 25-40%
Hutch diverticulum
congenital bladder diverticulum at the VUJ, in absence of posterior valves
VUR demographics
retrograde flow of urine from bladder ot ureter, 1-3% of kids, 40-50% of kids with UTI
more common in caucasians, M>F in newborns, then 5-6x F>M after age 1
VUR etiologies
primary (ectopic ureters, lack/short intravesicular ureteric course, detrusor muscle abnormality)
secondary: cystitis/UTI, bladder diverticulum, calculi)
grading VUR
1: ureter only
2: reflux to renal pelvis, no dilation/blunting
3: mild dilation of ureters/calyces
4: moderate dilation, tortuosity, blunting of calcyces
5: severe dilation and tortuosity
spinning top urethra
seen in young children/girls
- dilated posterior urethra resulting from increased bladder pressure against closed sphincter
- bladder retraining needed
ureterocele
congenital abnormal dilation of the distal ureter. intra (at UVJ) or extra-vesciular( below/medial to expected UVJ)
appears as cystic intravesciular mass near UVJ/early filling defect posteriorly
- 5-7X F>M, up to 10% bilateral
Think: duplication
Weigert-Meyer law
describes the relationship of renal moieties to drainage in a completely duplicated system
- upper: ectopic ureter (medial inferior), often ending in ureterocele, and usually obstructed
- lower: normal ureter insertion, reflux
mesoblastic nephroma
aka fetal renal hamartoma
- most common congenital renal mass
- solid unencapsulated mass, usually near the renal hilum, tends to invade renal parenchyma and surrounding structures
- classic and cellular subtypes (and mixed)
DDx for infant retroperitoneal mass
mesoblastic nephroma
MCDK
Wilms
Rhabdoid tumor
retroperitoneal sarcoma
teratoma
neuroblastoma
extrapulmonary sequestration
MCDK
multiple renal cysts of variable size, with thinning and fibrotic changes of the renal parenchyma
due to oibstruction of the UPJ
- usually prenatal Dx
- unilateral, non-functional kidney
Wilm’s tumor
aka nephroblastoma
most common pediatric renal malignancy and abdominal CA
- slight F>M, usually <5yo
what are nephrogenic rests?
persistent metanephric tissue, usually regress during childhood
- found in up to 100% of bilateral Wilm’s
nephroblastomatosis
single renal mass <1yo
mesopblastic nephroma
wilms
rhabdoid
single renal mass in 1-10yo
wilms
rhabdoid (rare, 2% peds malignancies)
clear cell sarcoma (rare younger than 6 mo)
omphalocele vs gastroschisis
OM: midline abdominal wall defect with herniation covered by peritoneum/membrane with the umbilical cord inserting on it. 50-70% have associated anomalies (genetic syndromes),. prognosis determined by other anomalies.
GS: abdominal wall defect (right of midline) without membrane covering herniated bowel. usually isolated. prognosis determined by bowel condition
pentalogy of Cantrell
classic 5 malformations:
1. midline abdo defect
2. lower sternal defect/cleft
3. anterior diaphragmatic defect
4. defect of the diaphragmatic pericardium
5. intracardiac defect
Other
- omphalocele
- cardiac position outside the chest, or rotated with apex pointing towards the chin,
other cardiac anomalies (septum, tetralogy, ebstein, LV diverticulum, effusions)
best clue for pentalogy of Cantrell?
ectopia cordis + omphalocele
Best clue for body stalk abnormality/limb-body-wall-complex
abdo wall defect + scoliosis
Body stalk abnormality
rare malformation, major abdo wall defect with organs (liver) develop outside the abdominal cavity/attached to placenta, severe kyphoscoliosis, and short/absent UC.
+/-
- craniofacial and vertebral anomalies
- renal abnormalities
- limb abnormalities
- bladder exstrophy
cloacal exstrophy
absence of normal bladder, anal atresia (lack normal anal dimple), low abdo wall defect
may have bifid scrotum/penis/clitoris
- look for renal abnormalities, spine anomalies, spinal bifida
when should soft markers be applied?
18-22 wks. Not before 16 and not after 24
strong ‘soft’ marker
thick NF
absent nasal bone in caucasians
moderate ‘soft’ markers
absent nasal bone in non-caucasians
mild lateral ventriculomegaly
bowel echogenicity > bone
weak ‘soft’ markers
intracardiac echogenic focus (brighter than bone)
renal pelvis >4mm
short femur <2.5th centile
short nasal bone
incomplete chorion and amnion membrane separation
hypercoiled umbilical cord
isolated single umbilical artery is a marker for?
other structural anomalies - recommend level 2 and follow up growth scans advised
*not aneuploidy marker
choroid plexus cysts are RF for?
Edward syndrome - increased LR by factor of 7X
however, isolated CPCs with no other structural abnormality very rare to have Tri18
holoprosencephaly is classic for ? trisomy
13 (seen in 75%)
if isolated abnormality though, only 4% incidence of chromosome abnormality
fetal skeletal dysplasia definition
heterogenous group of disorders related to the abN development/growth/maintenance of bone and cartilagenous tissues
- some are idiopathic, others genetic
- some are lethal
top 4 common skeletal dysplasias
achondrogenesis
Osteogenesis Imperfecta
thanatophoric dysplasia
achrondroplasia
features suspicious for skel dysplasia
growth deficiency
bowing/short long bones
vertebral defects
rib defects
multiple #
abnormal cranial shape
role of U/S for skel dysplasias
identification and narrowing of DDx
assessment of the involved bones/organs
predict lethality
U/S markers predictive of lethality in skel dysplasia
Most linked to the chest, including:
thoracic circumference <5th %ile at the level of 4chamber view
thorax:abdo circumference ratio <0.6
short thorax
ribs <70% of thoracic circumference
narrow AP on sag, concave/bell shaped thorax
Ectrodactyly
condition characterized by absence or malformation of one or more of the fingers or toes
clinodactyly
fingers curved/bent to one side
micromelia
shortening of the entire limb
rhizomelia
shortening of proximal segment of limb
mesomelia
shortening of the intermediate aspect of the limb
acromelia
shortening of the extremities involving the distal limb
thanatophoric dysplasia
lethal skel dysplasia
often abnormal skull shape & macrocranium, small thorax
normal bone mineralization, no fractures
hypomineralization in skeletal dysplasia
OI T2, achondrogenesis, hypophosphatasia
another name for Sturge Weber
encephalotrigeminal angiomatosis
sturge-weber signs
2/2 failure of cortical vein development -> congestion and infarcts.
- tram-track gyral calcs, volume loss, enlarged choroid plexi (ipsilateral)
- facial nevus flammus/port-wine
- choroidal angioma, buphthalmos, retinal telangiectatic vessels, scleral angioma, and iris heterochromia
