Diagnosis of LPD by USG & Doppler: How useful is RI of the corpus luteum ??

We know that the rupture of the follicle   leads to formation   of corpus luteum. We also know that Corpus luteum is responsible   for progesterone   production.  The functional efficacy of the corpus   luteum can be   assessed by Doppler   by assessing   the pericorpus  luteal   vascularity. A corpus    luteum that is functionally   normal and   produces adequate   amount of progesterone    shows corpus    luteal flow with RI 0.35-0.50  and PSV   10-15  cm /s. A clear   correlation   between R I of     corpus luteum   and plasma   progesterone levels   has been seen in natural cycle. RI of   the corpus luteum   can therefore be used as an adjunct to plasma    progesterone   assay   as an index of  luteal  function 

How useful is  RI of   the  spiral areries in early luteal phase??  Ans: Segmental uterine and ovarian artery  perfusion   demonstrates a significant correlation with histological    and hormonal markers of uterine receptivity   and may   aid assessment    of luteal   phase defect..

Soon   after rupture    of the follicle     the outer margin of endometrium also   becomes hyperechoic as a     result  of   progesterone exposure  but  with adequate    progesterone   levels in the  mid  luteal phase  the spiral   arteries    show  RI     of 0.48 -.52  . This   RI is lower than   in the preovulatory    phase because of smooth muscle    relaxing  effect of  progesterone.

What happens in LPD?? Inadequate   progesterone   production   and therefore    corpus   luteal inadequacy is suggested by high     resistance   flow in corpus   luteal   vessels. In luteal phase   defect because   of low   progesterone levels    the resistance   in the pericorpus   luteal vessels  is high.  Because    of low   progesterone    levels   there is inadequate   relaxation of the   muscularis  of the uterine artery    and therefore    the uterine artery    resistance is high   along with   higher   resistance   in its  branches-  the spiral   vessels.

A)Corpus   luteal flow in normal cycle    and in luteal   phase defect

Peri follicular    phase  -Normal -  0.56+- 0.06 , LPD -  0.58+-  0.04

LH  peak  day – Normal -0.44+- 0.04, LPD- 0.58+-  0.04

Mid  luteal  phase – Normal -0.42+- 0.06 , 0.58+- 0.04

 Late  luteal  phase – 0.50+-  0.04, LPD – 0.58 +- 0.04

Spiral   artery flow in normal   cycle   and in luteal   phase defect

Periovulatory   , control RI – 0.53+-  0.04 , LPD RI – 0.70+- 0.06

Mid  luteal ,  control  RI – 0.50+- 0.02 , LPD RI 0.72+- 0.06

 Late  luteal , Control RI – 0.51+- 0.04 , LPD RI – 0.72+- 0.04

  What is the relevance of basal scan??  Ans: This scan is done when   ovarian hormonal    levels   are at their baseline on days 2-3 of the menstrual cycle    . The ovaries    are silent and have no active follicle     or corpus    luteum at this stage. The scan   is done using   B mode ultrasound with color Doppler,     pulse Doppler,  three  dimenstional  ultrasound and 3D   power Doppler   . This scan   assesses   the ovarian     reserve and response   . It is also a key scan for ultrasound  diagnosis of   polycystic ovaries.