Laminitis Measurement

– Radiological measurements from the feet of horses with relevance to laminitis

REQUIREMNTS

Required radiograph: toe LM

HOW TO MEASURE

1. Draw the baseline bl

– Place toe base point bl1

– Place heel base point bl2

2. Draw the hoof line hw

– Place the point hw1 for a distal hoof wall

– Place the point hw2 for a proximal hoof wall

3. Draw the dp line

– Place the point dp1 for apex distal phalanx

– Place the point dp2 at the proximal limit of the extensor process of the distal phalanx

4. Draw the xb line for X-ray beam focus

– To find the points xb1 and xb2 place one circle at the beginning and the second at the end of middle phalanx

NOTE!

You can regulate the size of circles.

The measured values include:

angle S = dorsal hoof wall to ground base line

angle T = dorsal cortex of distal phalanx to ground base line

angle U = axis line of proximal phalanx to ground base line

angle H = T – S

angle R = T – U

FD = Founder Distance = distance between proximal hoof wall and proximal limit of the Extensor Process of the distal phalanx

Figure 1. Laminitis measurement

LEGEND

FD = Founder Distance

hw1 = distal hoof wall

hw2 = proximal hoof wall (skin-horn junction)

dp1 = apex distal phalanx

dp2 = proximal limit of the Extensor Process of the distal phalanx

xb =  x-ray beam focus

bl1 = toe base line point

bl2 = heel base line point

bl = base line

Tibial Plateau Leveling Osteotomy (TPLO) Measurement

– Measurement of the tibial plateau angle or tibial slope

REQUIREMNTS

Required radiograph: ML views of stifle and hock joint used for the measurement of the tibial plateau angle

NOTE!

– X-ray beam centered at stifle joint and collimated.

– Positioning for these radiographs must ensure that the medial and lateral femoral condyles are superimposed.

HOW TO MEASURE

1. Draw line (line 1) between the cranial (p1) and caudal (p2) aspects of the tibial plateau.
2. Draw another line (line 2) between the tibial intercondylar tubercles (p3) and the centre of talus (p4).
3. At the point of intersection of both lines, a perpendicular line (line 3) is drawn to the line connecting the talus (line 2).

The measured value:

The resulting angle is the tibial plateau angle.

Figure 1. TPLO measurement

LEGEND

p1 = cranial tibial plateau

p2 = caudal tibial plateau

p3 = tibial intercondylar tubercles

p4 = centre corpus talus

line 1: between p1 and p2

line 2: between p3 and p4

line 3: at intersection line 1 and line 2 perpendicular to line 2 (90°)

TPLO angle: between line 1 and line 3

Tibial Tuberosity Advancement (TTA) Measurement

– Use for the common tangent method for determining appropriate advancement cage size

HOW TO MEASURE

1. Draw line between central points of two circles fh1 and fh2.

– Place first circle which central point represents surface femur (fh1).

– Place second circle which central point represents surface tibia (fh2).

NOTE!

Two circles are supposed to touch.

2. Place the point p1 on apex patella.
3. Place the point p2 on tibial tuberosity.

NOTE!

There is a line from the point p1 to distal perpendicular (90°) at common tangent.

Common tangent is a tangential line between 2 circles and perpendicular to tibial plateau slope (line between central points of 2 circles).

These lines are calculated by the software automatically and don’t need be visible.

The measured value:

D – Distance for TTA

Figure 1. TTA measurement

LEGEND

fh1 = central point circle presents surface femur

fh2 = central point circle presents surface tibia

p1 = apex patella

p2 = tibial tuberosity

D – Distance for TTA

VD Thorax Measurement

– Measurement taken for the evaluation of cardiac size

Radiographic evaluation of cardiac size and subjective assessment of thoracic features is used in domestic animals as a primary diagnostic tool in the detection of heart disease and evaluation of its progression.

REQUIREMNTS

Required radiograph: ventrodorsal thoracic

HOW TO MEASURE

1. Measure the long axis of the heart (L).

– Place first point pl1 on the ventral border of the left main stem bronchus (cranioventral border of the carina).

– Place second point pl2 on the cardiac apex (the most distant point on the ventral contour of the cardiac radiographic image).

2. Measure the short axis of the heart (W).

– Place the points pw1 and pw2 at the widest point of the cardiac image on a line perpendicular to the long axis at the level of the caudal vena cava.

NOTE!

The line W is perpendicular to the line L, if the midpoint of this two axes is green – you can correct the position of these two lines until the point will be green.

3. Measure the width of the thorax.

– Place the points pt1 and pt2 at the width of the thorax at the point where rib six articulates with the vertebral column (T).

4. Measure the length of the clavicle.

– Place the points pcl1 and pcl2 at the length of the clavicle (C).

The following ratios are calculated:

L/W, W/T, W/C, L/C

Figure 1. Cardiac size measurement

LEGEND

C = clavicle length

pcl1 = left clavicle facet manubrium sternum

pcl2 = acromial end clavicle

Vertebral heart size (VHS) measurement

– Vertebral scale system to measure heart size of dogs

REQUIREMNTS

Required radiograph: lateral thoracic

Positioning of animal: left lateral recumbency

Radiograph is taken during inspiration

Anesthesia is not necessary

X-ray beam to thorax must be perpendicular

HOW TO MEASURE

1. Measure the long axis of the heart.

– Place first point pl1 on the ventral border of the left main stem bronchus (cranioventral border of the carina).

– Place second point pl2 on the cardiac apex (the most distant point on the ventral contour of the cardiac radiographic image). This dimension reflects the combined size of the left atrium and the left ventricle.

2. Measure the short axis of the heart.

– Place the points ps1 and ps2 at the widest point of the cardiac image on a line perpendicular to the long axis at the level of the caudal vena cava.

NOTE!

To get an accurate measurement result of the VHS method, the lines pl1-pl2 and ps1-ps2 should be perpendicular (90°) or close to perpendicular to each other. In this case the green points appear on the lines. The redder the points are, the less accurate is the VHS measurement value. If the dots are red, no result is shown because of its inaccuracy.

3. VHS (v)  = pl1-pl2 (long axis) + ps1-ps2 (short axis)

The result is expressed in units of vertebral lengths (v). The sum of the measurements on both axes constituted the VHS and data are expressed as mean ± SD (standard deviation).

The two measurements (long and short axis) are compared to the vertebrae starting at the cranial edge of thoracal 4 (T4) and a result was obtained for each axis.

Figure 1. VHS measurement

LEGEND

pl1-pl2 => long axis heart

ps1-ps2 => short axis heart (=widest point perpendicular to long axis)

pl1 = ventral border of left main bronchus stem

pl2 = cardiac apex

ps1 = cranial heart wall (widest point)

ps2 = caudal heart wall (widest point) close to caudal vena cava

pv1 = T4 cranial edge thoracic vertebrae

pv2 = T9 cranial edge thoracic vertebrae

v = length of one vertebra