- Email: [email protected]
Assessment of reduction in subcutaneous fat thickness after liposuction using magnetic resonance imaging
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Assessment of reduction in subcutaneous fat thickness after liposuction using magnetic resonance imaging This paper was accepted for presentation at the Annual Scientific Meeting of the American Society of Plastic Surgeons in Denver on September 24, 2011. Patients often ask how much reduction in the fat layer they may expect to see after liposuction. They also inquire as to how long it will take the swelling to go down.Plastic surgeons have not had evidence-based answers to these basic questions. Adipose tissue is now recognized as an important endocrine organ, affecting lipid metabolism and also the levels of inflammatory cytokines, which have been implicated in cardiovascular disease.1 A contemporaneous prospective study of 322 patients revealed a significant reduction in triglyceride level and white blood cell count after liposuction.2 This prospective study evaluated three women who underwent a total of 15 MRI scans before surgery and at intervals up to one year after surgery. There was no outside funding or insurance reimbursement. All MRI scans were performed using the same equipment, a 1.5 Tesla MRI scanner (General Electric, Fairfield, Conn.). For abdominal measurements, axial slices were used (Figure 1). The level of greatest subcutaneous fat thickness was measured. For measurements of the flanks and thighs,
Correspondence and communications coronal images were measured at the level of the hip joint (Figure 2). All patients underwent ultrasonic liposuction of the lower body (abdomen, flanks, buttocks, thighs, and knees) performed by the author using the Lysonix 3000 (Mentor Corp., Santa Barbara, Calif.) system, and a superwet (approximately 1:1 ratio of infusion to aspirate) technique. The mean age was 27.7 years (range, 24 to 33). The mean patient weight was 67.7 kg (range, 55.0 to 77.3 kg.). The average infusion volume was 3,150 cc (range, 2,800 cc to 3,400 cc). The average total aspirate volume was 2,917 cc (range, 2,500 cc to 3,250 cc). The combined data (combining all 5 sites) yielded the following overall reductions in fat thickness: at 1 month, 29.7%; 3.3 months, 39.4%; 9.3 months, 45.6%. This reduction was highly significant comparing the preoperative and 1-month (p Z 0.001) and preoperative and 3.3-month combined data (p Z 0.003). Cronbach’s alpha testing of left and right side reliability gave a mean value of 0.96 for the flanks and 0.97 for the thighs. Women carry most of their fat in the lower body. In fact, about 90% of the total body fat is located in the nonvisceral subcutaneous fat stores in women.3,4 This study examined these areas of major fat deposition in women. In 1994, Abate et al. validated MRI measurements with cadaveric anatomic dissections, determining that MRI measurements accurately evaluate visceral and subcutaneous adipose tissue mass.5 In the extremities, there is very little body fat deep to the investing muscle fascia. An axial image provides the needed information. However, the level of the slice along the thigh
Figure 1 Axial T1-weighted MRI scans of Patient 1 (above, left) before, (above, right) 3 months, (below, left) 6 months, and (below, right) 1 year after ultrasonic liposuction of lower body, arms and axillae, and breast augmentation. The fat appears white. Note the preponderance of subcutaneous fat, with minimal visceral fat. The subcutaneous fat is bordered by the rectus abdominis muscles, which appear dark. The iliac crests appear white because of fat in the bone marrow. The subcutaneous fat layer is reduced from 3.7 cm to 1.7 cm 1 year after surgery.
Correspondence and communications
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Figure 2 Coronal T1-weighted MRI scans of Patient 2 (above, left) before, (above, middle) 1 month, (above, right) 2 months, (below, left) 3.5 months, and (below, right) 9.5 months after ultrasonic liposuction of the lower body, and breast augmentation. Measurements are at the level of the maximum preoperative thickness of the flanks and outer thighs. Dark areas indicating postsurgical edema may be seen within the white areas that label subcutaneous fat.
could cause significant variation from one measurement to the next. Coronal slices were used instead because of the greater ease in identifying landmarks, and visualizing the level of maximum fat thickness. Coronal views allow all four measurements of the flanks and outer thighs to be made from one image (Figure 2), reducing the potential for error. The flanks and thighs are most useful because these areas typically have higher fat volumes than the inner thighs or knees and the differences are measured more easily. At one month, MRI scans showed a 29.7% reduction in thickness of the fat layer . At this follow-up time, there was a visible improvement in fullness in the treated areas, but not the maximum benefit (45.6%) that was revealed at later follow-up times. This finding suggests that two-thirds of the swelling (29.7/45.6) resolves in the first month and about 87% (39.4/45.6) of the swelling is gone 3.3 months after surgery, based on 9.3 months as the end-point for swelling. It is useful for the patient to know that 1 month after surgery, fully one-third of the swelling is still present. It is not unusual for plastic surgeons to see patients at this follow-up time who are concerned that the result may not be as dramatic as they had hoped. On the basis of these MRI findings, patients may be reassured that significant improvements are to be expected over the next few months. This gradual resolution of swelling is the basis for taking photographs 3 months after surgery. The reliability of measurements comparing left and right sides (0.96 and 0.97) was excellent. The mean weight loss was 3.7 lbs 3 months after surgery, so that the
patients’ caloric state during the study period was about neutral, with a modest weight loss expected from the fat removal. This information is the first available data regarding change in lower-body subcutaneous fat thickness after liposuction. This study introduces an original technique using a proven instrument for measuring changes in fat thickness after liposuction, and provides new information regarding the magnitude of the changes and the time course for resolution of swelling. Liposuction effectively reduces the thickness of the fat layer, by about 45%.
Disclosure The author has no conflicts of interest. This study received no outside funding.
References 1. Esposito K, Giugliano G, Scuderi N, Giugliano D. Role of adipokines in the obesity-inflammation relationship: the effect of fat removal. Plast Reconstr Surg. 2006;118:1048e57. 2. Swanson E. Prospective clinical study reveals significant reduction in triglyceride level and white cell count after liposuction and abdominoplasty and no change in cholesterol levels. Plast Reconstr Surg Scheduled for publication, September 2011. 3. Kvist H, Chowdhury B, Granga ˚rd U, Tyle ´n U, Sjo ¨stro ¨m L. Total and visceral adipose-tissue volumes derived from measurements
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with computed tomography in adult men and women: predictive equations. Am J Clin Nutr 1988;48:1351e61. 4. Ross R, Shaw KD, Martel Y, de Guise J, Avruch L. Adipose tissue distribution measured by magnetic resonance imaging in obese women. Am J Clin Nutr 1993;57:470e5. 5. Abate N, Burns D, Peshock RM, Garg A, Grundy SM. Estimation of adipose tissue mass by magnetic resonance imaging: validation against dissection in human cadavers. J Lipid Res. 1994;35: 1490e6.
Eric Swanson 11413 Ash Street, Leawood, KS 66211, United States E-mail address: [email protected] ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2011.07.002
Dynamic infrared thermography for the preoperative planning of microsurgical breast reconstruction: A comparison with CTA Dear Sir, Preoperative knowledge of the highly variable vascular anatomy of the abdominal wall via computed tomographic angiography (CTA) has revolutionized surgical planning,1e4
Figure 1 Preoperative computed tomographic angiogram (CTA) showing one suitable single medial row perforator supplying the right hemiabdomen, with a diameter of 2 mm. The other perforators were felt to be insufficient to supply a flap. This image shows one small perforator to the right of the umbilicus and two small perforators just to the left of the midline.
Figure 2 Thermal image after 10 min of cold challenge using a water pack at 5 C showing the presence of one ‘hot spot’ confirming the presence of the dominant perforator on the right and the lack of visible hot spots on the left.
reducing operating times, complications and improving outcomes.5,6 Our group has been highly influential in the elucidation of this method of imaging, however in the constant search for optimal outcomes and increased patient safety, we have trialled the infrared camera (Thermo Tracer TH 7800, NEC Avio Infrared Technologies, Tokyo). In this correspondence, we describe the first case, to our knowledge, in the literature using this device in surgical planning of deep inferior epigastric artery perforator flaps in comparison to CTA and discuss the potential advantages and limitations compared to contemporary imaging techniques.
Figure 3 Preoperative thermal image overlying the preoperative computed tomographic angiogram (CTA), showing the correlation between the findings of the two modalities (black arrows).
Assessment of reduction in subcutaneous fat thickness after liposuction using magnetic resonance imaging This paper was accepted for presentation at the Annual Scientific Meeting of the American Society of Plastic Surgeons in Denver on September 24, 2011. Patients often ask how much reduction in the fat layer they may expect to see after liposuction. They also inquire as to how long it will take the swelling to go down.Plastic surgeons have not had evidence-based answers to these basic questions. Adipose tissue is now recognized as an important endocrine organ, affecting lipid metabolism and also the levels of inflammatory cytokines, which have been implicated in cardiovascular disease.1 A contemporaneous prospective study of 322 patients revealed a significant reduction in triglyceride level and white blood cell count after liposuction.2 This prospective study evaluated three women who underwent a total of 15 MRI scans before surgery and at intervals up to one year after surgery. There was no outside funding or insurance reimbursement. All MRI scans were performed using the same equipment, a 1.5 Tesla MRI scanner (General Electric, Fairfield, Conn.). For abdominal measurements, axial slices were used (Figure 1). The level of greatest subcutaneous fat thickness was measured. For measurements of the flanks and thighs,
Correspondence and communications coronal images were measured at the level of the hip joint (Figure 2). All patients underwent ultrasonic liposuction of the lower body (abdomen, flanks, buttocks, thighs, and knees) performed by the author using the Lysonix 3000 (Mentor Corp., Santa Barbara, Calif.) system, and a superwet (approximately 1:1 ratio of infusion to aspirate) technique. The mean age was 27.7 years (range, 24 to 33). The mean patient weight was 67.7 kg (range, 55.0 to 77.3 kg.). The average infusion volume was 3,150 cc (range, 2,800 cc to 3,400 cc). The average total aspirate volume was 2,917 cc (range, 2,500 cc to 3,250 cc). The combined data (combining all 5 sites) yielded the following overall reductions in fat thickness: at 1 month, 29.7%; 3.3 months, 39.4%; 9.3 months, 45.6%. This reduction was highly significant comparing the preoperative and 1-month (p Z 0.001) and preoperative and 3.3-month combined data (p Z 0.003). Cronbach’s alpha testing of left and right side reliability gave a mean value of 0.96 for the flanks and 0.97 for the thighs. Women carry most of their fat in the lower body. In fact, about 90% of the total body fat is located in the nonvisceral subcutaneous fat stores in women.3,4 This study examined these areas of major fat deposition in women. In 1994, Abate et al. validated MRI measurements with cadaveric anatomic dissections, determining that MRI measurements accurately evaluate visceral and subcutaneous adipose tissue mass.5 In the extremities, there is very little body fat deep to the investing muscle fascia. An axial image provides the needed information. However, the level of the slice along the thigh
Figure 1 Axial T1-weighted MRI scans of Patient 1 (above, left) before, (above, right) 3 months, (below, left) 6 months, and (below, right) 1 year after ultrasonic liposuction of lower body, arms and axillae, and breast augmentation. The fat appears white. Note the preponderance of subcutaneous fat, with minimal visceral fat. The subcutaneous fat is bordered by the rectus abdominis muscles, which appear dark. The iliac crests appear white because of fat in the bone marrow. The subcutaneous fat layer is reduced from 3.7 cm to 1.7 cm 1 year after surgery.
Correspondence and communications
129
Figure 2 Coronal T1-weighted MRI scans of Patient 2 (above, left) before, (above, middle) 1 month, (above, right) 2 months, (below, left) 3.5 months, and (below, right) 9.5 months after ultrasonic liposuction of the lower body, and breast augmentation. Measurements are at the level of the maximum preoperative thickness of the flanks and outer thighs. Dark areas indicating postsurgical edema may be seen within the white areas that label subcutaneous fat.
could cause significant variation from one measurement to the next. Coronal slices were used instead because of the greater ease in identifying landmarks, and visualizing the level of maximum fat thickness. Coronal views allow all four measurements of the flanks and outer thighs to be made from one image (Figure 2), reducing the potential for error. The flanks and thighs are most useful because these areas typically have higher fat volumes than the inner thighs or knees and the differences are measured more easily. At one month, MRI scans showed a 29.7% reduction in thickness of the fat layer . At this follow-up time, there was a visible improvement in fullness in the treated areas, but not the maximum benefit (45.6%) that was revealed at later follow-up times. This finding suggests that two-thirds of the swelling (29.7/45.6) resolves in the first month and about 87% (39.4/45.6) of the swelling is gone 3.3 months after surgery, based on 9.3 months as the end-point for swelling. It is useful for the patient to know that 1 month after surgery, fully one-third of the swelling is still present. It is not unusual for plastic surgeons to see patients at this follow-up time who are concerned that the result may not be as dramatic as they had hoped. On the basis of these MRI findings, patients may be reassured that significant improvements are to be expected over the next few months. This gradual resolution of swelling is the basis for taking photographs 3 months after surgery. The reliability of measurements comparing left and right sides (0.96 and 0.97) was excellent. The mean weight loss was 3.7 lbs 3 months after surgery, so that the
patients’ caloric state during the study period was about neutral, with a modest weight loss expected from the fat removal. This information is the first available data regarding change in lower-body subcutaneous fat thickness after liposuction. This study introduces an original technique using a proven instrument for measuring changes in fat thickness after liposuction, and provides new information regarding the magnitude of the changes and the time course for resolution of swelling. Liposuction effectively reduces the thickness of the fat layer, by about 45%.
Disclosure The author has no conflicts of interest. This study received no outside funding.
References 1. Esposito K, Giugliano G, Scuderi N, Giugliano D. Role of adipokines in the obesity-inflammation relationship: the effect of fat removal. Plast Reconstr Surg. 2006;118:1048e57. 2. Swanson E. Prospective clinical study reveals significant reduction in triglyceride level and white cell count after liposuction and abdominoplasty and no change in cholesterol levels. Plast Reconstr Surg Scheduled for publication, September 2011. 3. Kvist H, Chowdhury B, Granga ˚rd U, Tyle ´n U, Sjo ¨stro ¨m L. Total and visceral adipose-tissue volumes derived from measurements
130
Correspondence and communications
with computed tomography in adult men and women: predictive equations. Am J Clin Nutr 1988;48:1351e61. 4. Ross R, Shaw KD, Martel Y, de Guise J, Avruch L. Adipose tissue distribution measured by magnetic resonance imaging in obese women. Am J Clin Nutr 1993;57:470e5. 5. Abate N, Burns D, Peshock RM, Garg A, Grundy SM. Estimation of adipose tissue mass by magnetic resonance imaging: validation against dissection in human cadavers. J Lipid Res. 1994;35: 1490e6.
Eric Swanson 11413 Ash Street, Leawood, KS 66211, United States E-mail address: [email protected] ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2011.07.002
Dynamic infrared thermography for the preoperative planning of microsurgical breast reconstruction: A comparison with CTA Dear Sir, Preoperative knowledge of the highly variable vascular anatomy of the abdominal wall via computed tomographic angiography (CTA) has revolutionized surgical planning,1e4
Figure 1 Preoperative computed tomographic angiogram (CTA) showing one suitable single medial row perforator supplying the right hemiabdomen, with a diameter of 2 mm. The other perforators were felt to be insufficient to supply a flap. This image shows one small perforator to the right of the umbilicus and two small perforators just to the left of the midline.
Figure 2 Thermal image after 10 min of cold challenge using a water pack at 5 C showing the presence of one ‘hot spot’ confirming the presence of the dominant perforator on the right and the lack of visible hot spots on the left.
reducing operating times, complications and improving outcomes.5,6 Our group has been highly influential in the elucidation of this method of imaging, however in the constant search for optimal outcomes and increased patient safety, we have trialled the infrared camera (Thermo Tracer TH 7800, NEC Avio Infrared Technologies, Tokyo). In this correspondence, we describe the first case, to our knowledge, in the literature using this device in surgical planning of deep inferior epigastric artery perforator flaps in comparison to CTA and discuss the potential advantages and limitations compared to contemporary imaging techniques.
Figure 3 Preoperative thermal image overlying the preoperative computed tomographic angiogram (CTA), showing the correlation between the findings of the two modalities (black arrows).