This document discusses various imaging-based methods for quantifying pleural effusion volumes, including: - Chest X-ray, where effusions become visible at 50ml and can obscure the diaphragm at 500ml. - Ultrasound estimates effusion size by counting intercostal spaces and compares to drained volume. It provides four formulas to estimate volume based on effusion height and distance to lung borders. - CT uses a classification rule based on anterior-posterior quartile location and depth measurements to categorize effusions as small, moderate, or large. It finds effusion depths of 2, 4, 6, 8, and 10cm represent volumes of around 200, 500, 800,

1. IMAGING BASED
QUANTIFICATION OF PLEURAL
EFFUSION
 DR. SAJAL AGARWAL
 Deptt. Of Radiodiagnosis,
 GRMC Gwalior

2. INTRODUCTION
 Pleural effusion tends to be used as a catch-
all term denoting a collection of fluid within the
pleural space.
 Normally the pleural cavities contain
approximately 15 ml of fluid . Any process
which results in more fluid forming than can be
absorbed will produce a pleural effusion.

3.  There are many causes of pleural effusion that
are broadly split into transudates and
exudates. This categorisation relies upon the
biochemical analysis of aspirated pleural fluid.

5. XRAY QUANTIFICATION
 Pleural effusions became visible as a
meniscus on the lateral chest radiograph at a
volume of approximately 50 ml; at a volume of
200 ml, the meniscus could be identified on
the posteroanterior radiograph. At a volume of
about 500 ml, the meniscus obscured the
hemidiaphragm.

9. USG QUANTIFICATION
 Effusion size was estimated by the recognised
method of counting intercostal spaces (ICS)
from costophrenic angle at post axillary
line(small- localised to 1 ICS, medium 2–3
ICS, large ≥4 ICS). Effusion size reported was
compared to actual volume of fluid drained (till
‘dry’ or ‘safe aspiration’).

10. USG QUANTIFICATION

11.  Erect 1 (Goecke 1): EV=X×90,
 where EV=estimated effusion volume (mL); X=craniocaudal
extent (cm) of the effusion at the dorsolateral chest wall
measured in erect/sitting position with the probe oriented
longitudinally; 90=empirical factor/constant
 Erect 2 (Goecke 2): EV=(X+LDD)×70,
 where EV=estimated effusion volume (mL); X=craniocaudal
extent of the effusion at the dorsolateral chest wall measured
in the erect/sitting position with the probe oriented
longitudinally; LDD=lung base to mid-diaphragm
distance/subpulmonary height of the effusion (cm);
70=empirical factor/constant

13.  Supine 1 (Eibenberger): EV=47.6X-837,
 where EV=estimated effusion volume (mL);
X=maximum perpendicular distance between the
pulmonary surface and the chest wall at maximal
inspiration (mm) with the probe in the transverse
position, perpendicular to the chest wall .
 Supine 2 (Balik): EV=20X,
 where EV=estimated effusion volume (mL);
X=maximum perpendicular distance between the
pulmonary surface and chest wall at maximal
inspiration (mm) with the probe in transverse
position, perpendicular to the chest wall

14. CT QUANTIFICATION
 An easy, two-step classification rule was
developed based on AP quartile and depth
measurements. First, AP quartile is estimated.
For borderline cases near the quartile bounds
(ie, close to 25% or 50%), maximum AP depth
is measured as a second step.

16.  Criteria for Three-Point Prediction Rule
Effusion Size Criterion
AP Quartile AP Depth
Small 0%-25% < 3.0 cm
Moderate 25%-50% 3.0-10.0 cm
Large 50%-75% > 10.0 cm
or 75%-100%

18.  Dimension b (effusion depth) was measured
perpendicular to the parietal pleura on
transversal scan where the greatest depth was
found by scrolling all the image.
 It can be stated, after slight rounding, that the
greatest effusion depths of 2, 4, 6, 8, and 10
cm represent volumes of 200, 500, 800, 1100,
and 1400 ml of pleural effusion, respectively.

19. THANK YOU!