ABC/2
Updates to Article Attributes
Body
was changed:
Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus trial eligibility) which is often under-reported1. The ABC/2 Formula is a fast and simple method for estimating the volume of a haemorrhage (or other ellipsoid lesion) which does not require volumetric 3D analysis or software. It has been well-validated and correlates highly with volumes calculated by planimetric techniques2,3.
Formula:
First described by Kwak et al4 and popularized by Kothari et al.2:
-
A x B x C / 2A = greatest haemorrhage diameter in the axial plane.B = haemorrhage diameter at 90 degrees to A in the axial plane.-
C = originally described as the number of CT slices with hemorrhage multiplied by the slice thickness, but can more simply be substituted with the cranio-caudal diameter of the haemorrhage where there is access to multiplanar reformats1.
If the measurements are made in cm, then the volume will be in cc (ml).
Mathematical Basis:
The above formula is based on 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
If π is estimated as 3, then the formula can be simplified to ABC/2.
Interpretation:
A baseline intracerebral haemorrhage volume of >50-60ml is a poor prognostic marker5.
Pitfalls:
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 irregularly shaped)3. An ABC/3 formula has been suggested for these lesions3although not yet validated.
Formula
First described by Kwak et al4 and popularized by Kothari et al.2:
-
A x B x C / 2
- A = greatest haemorrhage diameter in the axial plane.
- B = haemorrhage diameter at 90 degrees to A in the axial plane.
- C = originally described as the number of CT slices with hemorrhage multiplied by the slice thickness, but can simply be substituted with the cranio-caudal diameter of the haemorrhage where there is access to multiplanar reformats1.
If the measurements are made in cm, then the volume will be in cc (ml).
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 >50-60ml is a poor prognostic marker5.
Pitfalls
- 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)3. An ABC/3 formula has been suggested for these lesions3 although has not yet been validated.
-<p>Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus trial eligibility) which is often under-reported<sup>1</sup>. The ABC/2 Formula is a fast and simple method for estimating the volume of a haemorrhage (or other ellipsoid lesion) which does not require volumetric 3D analysis or software. It has been well-validated and correlates highly with volumes calculated by planimetric techniques<sup>2,3</sup>.</p><p><strong>Formula:</strong></p><p>First described by Kwak et al<sup>4 </sup>and popularized by Kothari et al.<sup>2</sup>:</p><ul><li>A x B x C / 2<ul>- +<p>Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus trial eligibility) which is often under-reported<sup>1</sup>. The ABC/2 Formula is a fast and simple method for estimating the volume of a haemorrhage (or other ellipsoid lesion) which does not require volumetric 3D analysis or software. It has been well-validated and correlates highly with volumes calculated by planimetric techniques<sup>2,3</sup>.</p><h6><strong>Formula</strong></h6><p>First described by Kwak et al<sup>4 </sup>and popularized by Kothari et al.<sup>2</sup>:</p><ul><li>A x B x C / 2<ul>
-<li>C = originally described as the number of CT slices with hemorrhage multiplied by the slice thickness, but can more simply be substituted with the cranio-caudal diameter of the haemorrhage where there is access to multiplanar reformats<sup>1</sup>.</li>- +<li>C = originally described as the number of CT slices with hemorrhage multiplied by the slice thickness, but can simply be substituted with the cranio-caudal diameter of the haemorrhage where there is access to multiplanar reformats<sup>1</sup>.</li>
-</li></ul><p>If the measurements are made in cm, then the volume will be in cc (ml).</p><p><strong>Mathematical Basis:</strong></p><p>The above formula is based on the formula for the volume of an ellipsoid, which is:</p><ul><li>4/3 π x (A/2) x (B/2) x (C/2)<ul><li>Where A, B and C are the three diameters</li></ul>-</li></ul><p>If π is estimated as 3, then the formula can be simplified to ABC/2.</p><p><strong>Interpretation:</strong></p><p>A baseline intracerebral haemorrhage volume of <!--[if gte mso 9]><xml>- +</li></ul><p>If the measurements are made in cm, then the volume will be in cc (ml).</p><h6><strong>Mathematical Basis</strong></h6><p>The above formula is a simplified version of the formula for the volume of an ellipsoid, which is:</p><ul><li>4/3 π x (A/2) x (B/2) x (C/2)<ul><li>Where A, B and C are the three diameters of the ellipsoid.</li></ul>
- +</li></ul><p>If π is estimated as 3, then the formula can be simplified to ABC/2.</p><h6><strong>Interpretation</strong></h6><p>A baseline intracerebral haemorrhage volume of <!--[if gte mso 9]><xml>
-</xml><![endif]-->>50-60ml is a poor prognostic marker<sup>5</sup>.</p><p><!--[if gte mso 9]><xml>- +</xml><![endif]-->>50-60ml is a poor prognostic marker<sup>5</sup>.</p><h6>
- +<!--[if gte mso 9]><xml>
-<![endif]--><strong>Pitfalls:</strong></p><ul>- +<![endif]--><strong>Pitfalls</strong>
- +</h6><ul>
-<li>Overestimates oral anticoagulant related intracerebral haemorrhage volumes (because they are often irregularly shaped)<sup>3</sup>. An ABC/3 formula has been suggested for these lesions<sup>3</sup> although not yet validated.</li>- +<li>Overestimates oral anticoagulant related intracerebral haemorrhage volumes (because they are often irregular in shape)<sup>3</sup>. An ABC/3 formula has been suggested for these lesions<sup>3</sup> although has not yet been validated.</li>
References changed:
- 1. Barras C, Asadi H, Phal P, Tress B, Davis S, Desmond P. Audit of CT Reporting Standards in Cases of Intracerebral Haemorrhage at a Comprehensive Stroke Centre in Australia. J Med Imaging Radiat Oncol. 2016;60(6):720-727. <a href="https://doi.org/10.1111/1754-9485.12491">doi:10.1111/1754-9485.12491</a>
- 2. Kothari R, Brott T, Broderick J et al. The ABCs of Measuring Intracerebral Hemorrhage Volumes. Stroke. 1996;27(8):1304-1305. <a href="https://doi.org/10.1161/01.str.27.8.1304">doi:10.1161/01.str.27.8.1304</a>
- 3. Huttner H, Steiner T, Hartmann M et al. Comparison of ABC/2 Estimation Technique to Computer-Assisted Planimetric Analysis in Warfarin-Related Intracerebral Parenchymal Hemorrhage. Stroke. 2006;37(2):404-408. <a href="https://doi.org/10.1161/01.str.0000198806.67472.5c">doi:10.1161/01.str.0000198806.67472.5c</a>
- 4. Kwak R, Kadoya S, Suzuki T. Factors Affecting the Prognosis in Thalamic Hemorrhage. Stroke. 1983;14(4):493-500. <a href="https://doi.org/10.1161/01.str.14.4.493">doi:10.1161/01.str.14.4.493</a>
- 5. Butcher K & Laidlaw J. Current Intracerebral Haemorrhage Management. J Clin Neurosci. 2003;10(2):158-167. <a href="https://doi.org/10.1016/s0967-5868(02)00324-7">doi:10.1016/s0967-5868(02)00324-7</a>
Tags changed:
- intracerebral haemorrhage
- intracranial haemorrhage
- volumetry
- formula
- neuro
- cns
Sections changed:
- Approach
- Classifications
Systems changed:
- Central Nervous System
Unable to process the form. Check for errors and try again.