•
Validity of the Sesamoid Index in the Diagnosis of Acromegaly 1
Diagnostic Radiology
Thomas R. Duncan, M.D. Sesamoid indices of 100 control and 10 acromegalic subjects were determined and the results compared with previous studies. It was found that a substantial overlap of values exists between the two groups and that the range of values for both groups is substantially wider than previous studies have indicated. INDEX TERMS:
Acromegaly. Hand
Radiology 115:617-619, June 1975
• is defined as the product in millimeters of the height and width of the medial sesamoid at the metacarpophalangeal joint of the thumb. The index as an aid to the diagnosis of aero ... megaly has received widely varying evaluations in the literature. The first measurements reported by Kleinberg, Young and Kupperman (2) indicated clearly separate normal and acromegalic groups. Subsequent measurements by Lin and Lee (3) yielded overlap of the control and acromegalic groups and also showed a sex variation with male control patients having a substantially larger average index than females. Anton (1) showed similar higher control values, male sex bias, and obvious overlap of the control and acromegalic groups. The following study was obtained to further clarify the validity of the sesamoid index in the diagnosis of acromegaly.
METHOD
HE SESAMOID INDEX
T
Hand radiographs of both the control and acromegalic groups were obtained at a 40-inch (102-cm) distance with the palm and thumb flat against the cassette. Measurements of the maximum height and width taken at right angles of the medial sesamoid of the metacarpophalangeal joint of the thumb were made with a ruler to the nearest half millimeter. The product of these measurements was then calculated to determine the sesamoid index. The control subjects were randomly selected and included a sexual and racial mixture in a wide age spectrum. These people had closed epiphyses and no bone diseases. Most of the radiographs were of the right hand.
Fig. 1. Smallest sesamoid in the control group with an index of 7.5. Subject was L. H., a 77-year-old man. Fig. 2. Smallest sesamoid in the acromegalic group with an index of 16. Subject was V. C., a 24-year-old woman. Fig. 3. Largest sesamoid in the control group with an index of 49. 1 From the Department of Radiology (T. R. D., Associate Clinical Professor of Radiology), Vanderbilt University, Nashville, Tenn. 37232. Accepted for publication in November 1974. shan
617
618
THOMAS
R.
June 1975
DUNCAN
RESULTS
Control Group Sesamoid index values of the control group are presented in Table I. Male control indices ranged from 7.5 to 48. An index of 48 is substantially higher than those extremes published by Kleinberg, Lin, and Anton of 29, 36, and 38.5, respectively. Because of the high value, the subject with the index of 48 was screened for acromegaly with radiographs of the sella, heel pad and ungual tufts, and further evaluated by history and physical appearance. No evidence to support acromegaly was present. The femare control indices ranged from 12 to 33 and correlated well with previous papers (12-29, Kleinberg; 10-33, Lin; and 6.25-28, Anton). Only 2 of the 47
Table II:
Age Distribution of Control Subjects with Sesamoid Indices over 30 Age
Number of Subjects Indices Above 30
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80 up
8 26 13 21 10 7 10 5 100
Total
Table III: Fig. 4. Largest sesamoid in the acromegalic group with an index of 63. Note the elongated ungual tufts incorporated into the phalangeal bases.
1. V. C. 2. E. L.
The acromegalic group comprised those patients with definite clinical and radiographic findings of acromegaly. Typical radiographic changes included enlargement of the sella, increase in heel pad thickness, enlargement of articular cartilages and hypertrophy of the ungual tufts. All borderline cases were excluded. Table I: Sesamoid Index
0-6 7-9 10-12 13-15 16-18 19-21 22-24 25-27 28-30 31-33 34-36 37-39 40-42 43-45 46-48 49 up. Total
Male
0 1 0 0 8 9 9 8 7 3 4
0
2 1 1 0 53
3. V. S. 4. M. L. 5. P. F. 6. R. E. 7. M. S. 8. E. M. 9. M. S. 10. A. H.
0 0 3 5 8 13 7 5 5 1 0 0 0 0 0 0
47
Total
0 1
3 5 16 22 16 13
12 4 4 0 2 1 1
0 100
12
Acromegalic Patients
Age
Race
Sex
Sesamoid Index
24 41 53 50 30 30 29 48 40 59
W W
F F F F M M F M M M
16.0 27.5 32.5 33.0 33.0 33.0 33.0 33.0 49.0 63.0
B B
W W B
W W W
Sesamoid Values of the 18 Black Subjects in the Control Group
Table IV:
Control Group Female
1 1 0 1 1 4 3 1
Sex
Age
Sesamoid Index
1. F 2. f
23 31 55 62 44 19 46 40 21 54 39 84 83 16 43 64 75 69
13.5 18.0 18.0 20.0 20.0 24.0 24.0 29.25 29.25 30.0 30.0 30.0 30.0 31.5 33.0 35.0 35.0 42.0
3. M 4. F 5. F 6. M 7. M 8. F 9. M 10. F 11. M 12. M 13. F
14. 15. 16. 17. 18.
M M M M M
VALiDITY
Vol. 115
619
OF THE SESAMOID INDEX
women had indices above 30; one was 65 years of age, the other 83. Median values of 20 for females and 24.75 for males were virtually identical to those previously reported (1, 3). The age distribution of the control subjects with sesamoid indices over 30 is shown in Table II. A greater percentage of the older subjects had indices above 30. Ten of the 12 control subjects with indices over 30 were beyond 40 years of age. Acromegalic Group Sesamoid indices for the 10 acromegalic patients are listed in Table III. The acromegalic sesamoid index ranged from 16 to 63 with a median of 33. The low extreme of 16 was well below that of previously published reports (30-63, Kleinberg; 22-52, Lin; and 22.5-45, Anton). CONCLUSION
The sesamoid index is a weak secondary diagnostic indicator for acromegaly because of the substantial overlap of values between the normal and acromegalic
Diagnostic Radiology
groups. A sesamoid index below 30 mitigates against but does not exclude the diagnosis of acromegaly; an acromegalic wag. observed with an index as low as 16. An index above 30 occurs frequently in normal males over age 40 as well as in most acromegalics.
Department of Radiology Vanderbilt University Nashville, Tenn. 37232
REFERENCES 1. Anton HC: Hand measurements in acromegaly. Clin Radiol 23:445-450, 1972 2. Kleinberg DL, Young IS, Kupperman HS: The sesamoid index. An aid in the diagnosis of acromegaly. Ann Intern Med 64: 1075-1078, May 1966 3. Lin SR, Lee KF: Relative value of some radiographic measurements of the hand in the diagnosis of acromegaly. Invest Radiol 6:426-431, Nov-Dec 1971 4. Murray RO, Jacobson HG: The Radiology of Skeletal Disorders. Baltimore, Williams & Wilkins, 1972, pp 564-565 5. Poznanski AK: The Hand in Radiologic Diagnosis. Philadelphia, Saunders, 1974, pp 48-49,511
Validity of the Sesamoid Index in the Diagnosis of Acromegaly 1
Diagnostic Radiology
Thomas R. Duncan, M.D. Sesamoid indices of 100 control and 10 acromegalic subjects were determined and the results compared with previous studies. It was found that a substantial overlap of values exists between the two groups and that the range of values for both groups is substantially wider than previous studies have indicated. INDEX TERMS:
Acromegaly. Hand
Radiology 115:617-619, June 1975
• is defined as the product in millimeters of the height and width of the medial sesamoid at the metacarpophalangeal joint of the thumb. The index as an aid to the diagnosis of aero ... megaly has received widely varying evaluations in the literature. The first measurements reported by Kleinberg, Young and Kupperman (2) indicated clearly separate normal and acromegalic groups. Subsequent measurements by Lin and Lee (3) yielded overlap of the control and acromegalic groups and also showed a sex variation with male control patients having a substantially larger average index than females. Anton (1) showed similar higher control values, male sex bias, and obvious overlap of the control and acromegalic groups. The following study was obtained to further clarify the validity of the sesamoid index in the diagnosis of acromegaly.
METHOD
HE SESAMOID INDEX
T
Hand radiographs of both the control and acromegalic groups were obtained at a 40-inch (102-cm) distance with the palm and thumb flat against the cassette. Measurements of the maximum height and width taken at right angles of the medial sesamoid of the metacarpophalangeal joint of the thumb were made with a ruler to the nearest half millimeter. The product of these measurements was then calculated to determine the sesamoid index. The control subjects were randomly selected and included a sexual and racial mixture in a wide age spectrum. These people had closed epiphyses and no bone diseases. Most of the radiographs were of the right hand.
Fig. 1. Smallest sesamoid in the control group with an index of 7.5. Subject was L. H., a 77-year-old man. Fig. 2. Smallest sesamoid in the acromegalic group with an index of 16. Subject was V. C., a 24-year-old woman. Fig. 3. Largest sesamoid in the control group with an index of 49. 1 From the Department of Radiology (T. R. D., Associate Clinical Professor of Radiology), Vanderbilt University, Nashville, Tenn. 37232. Accepted for publication in November 1974. shan
617
618
THOMAS
R.
June 1975
DUNCAN
RESULTS
Control Group Sesamoid index values of the control group are presented in Table I. Male control indices ranged from 7.5 to 48. An index of 48 is substantially higher than those extremes published by Kleinberg, Lin, and Anton of 29, 36, and 38.5, respectively. Because of the high value, the subject with the index of 48 was screened for acromegaly with radiographs of the sella, heel pad and ungual tufts, and further evaluated by history and physical appearance. No evidence to support acromegaly was present. The femare control indices ranged from 12 to 33 and correlated well with previous papers (12-29, Kleinberg; 10-33, Lin; and 6.25-28, Anton). Only 2 of the 47
Table II:
Age Distribution of Control Subjects with Sesamoid Indices over 30 Age
Number of Subjects Indices Above 30
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80 up
8 26 13 21 10 7 10 5 100
Total
Table III: Fig. 4. Largest sesamoid in the acromegalic group with an index of 63. Note the elongated ungual tufts incorporated into the phalangeal bases.
1. V. C. 2. E. L.
The acromegalic group comprised those patients with definite clinical and radiographic findings of acromegaly. Typical radiographic changes included enlargement of the sella, increase in heel pad thickness, enlargement of articular cartilages and hypertrophy of the ungual tufts. All borderline cases were excluded. Table I: Sesamoid Index
0-6 7-9 10-12 13-15 16-18 19-21 22-24 25-27 28-30 31-33 34-36 37-39 40-42 43-45 46-48 49 up. Total
Male
0 1 0 0 8 9 9 8 7 3 4
0
2 1 1 0 53
3. V. S. 4. M. L. 5. P. F. 6. R. E. 7. M. S. 8. E. M. 9. M. S. 10. A. H.
0 0 3 5 8 13 7 5 5 1 0 0 0 0 0 0
47
Total
0 1
3 5 16 22 16 13
12 4 4 0 2 1 1
0 100
12
Acromegalic Patients
Age
Race
Sex
Sesamoid Index
24 41 53 50 30 30 29 48 40 59
W W
F F F F M M F M M M
16.0 27.5 32.5 33.0 33.0 33.0 33.0 33.0 49.0 63.0
B B
W W B
W W W
Sesamoid Values of the 18 Black Subjects in the Control Group
Table IV:
Control Group Female
1 1 0 1 1 4 3 1
Sex
Age
Sesamoid Index
1. F 2. f
23 31 55 62 44 19 46 40 21 54 39 84 83 16 43 64 75 69
13.5 18.0 18.0 20.0 20.0 24.0 24.0 29.25 29.25 30.0 30.0 30.0 30.0 31.5 33.0 35.0 35.0 42.0
3. M 4. F 5. F 6. M 7. M 8. F 9. M 10. F 11. M 12. M 13. F
14. 15. 16. 17. 18.
M M M M M
VALiDITY
Vol. 115
619
OF THE SESAMOID INDEX
women had indices above 30; one was 65 years of age, the other 83. Median values of 20 for females and 24.75 for males were virtually identical to those previously reported (1, 3). The age distribution of the control subjects with sesamoid indices over 30 is shown in Table II. A greater percentage of the older subjects had indices above 30. Ten of the 12 control subjects with indices over 30 were beyond 40 years of age. Acromegalic Group Sesamoid indices for the 10 acromegalic patients are listed in Table III. The acromegalic sesamoid index ranged from 16 to 63 with a median of 33. The low extreme of 16 was well below that of previously published reports (30-63, Kleinberg; 22-52, Lin; and 22.5-45, Anton). CONCLUSION
The sesamoid index is a weak secondary diagnostic indicator for acromegaly because of the substantial overlap of values between the normal and acromegalic
Diagnostic Radiology
groups. A sesamoid index below 30 mitigates against but does not exclude the diagnosis of acromegaly; an acromegalic wag. observed with an index as low as 16. An index above 30 occurs frequently in normal males over age 40 as well as in most acromegalics.
Department of Radiology Vanderbilt University Nashville, Tenn. 37232
REFERENCES 1. Anton HC: Hand measurements in acromegaly. Clin Radiol 23:445-450, 1972 2. Kleinberg DL, Young IS, Kupperman HS: The sesamoid index. An aid in the diagnosis of acromegaly. Ann Intern Med 64: 1075-1078, May 1966 3. Lin SR, Lee KF: Relative value of some radiographic measurements of the hand in the diagnosis of acromegaly. Invest Radiol 6:426-431, Nov-Dec 1971 4. Murray RO, Jacobson HG: The Radiology of Skeletal Disorders. Baltimore, Williams & Wilkins, 1972, pp 564-565 5. Poznanski AK: The Hand in Radiologic Diagnosis. Philadelphia, Saunders, 1974, pp 48-49,511
