The volume of a trephine needle core biopsy can be determined from its dimensions.
Parameters:
(1) length of the core before processing in mm
(2) diameter of the core before processing in mm (approximately inner diameter of biopsy needle)
(3) length of the core after processing in mm
(4) diameter of the core after processing in mm
volume of a core biopsy in cubic mm =
= PI() * ((diameter in mm)^2) / 4 * (length in mm)
The smaller the needle gauge used, the greater the diameter of the core and its volume.
|
Needle Gauge
|
Inner Diameter
|
|
11
|
1.73 mm
|
|
8
|
2.72 mm
|
Size measurement is easier when there is a single core.
Blood clot should not be included in the measurement.
Cortical bone may be helpful in the diagnosis of some bone disorders, but may have limited use in the diagnosis of hematologic disorders.
The bone marrow may shrink during processing (up to 25%).
