Patient Selection (Fig.1)
We retrospectively reviewed the patients with renal transplant admitted previously for a study in our institution,
who had undergone lumbar spine QCT and DEXA scans,
between the 2013 and 2017.
From those,
we selected the patients who had the criteria to realize DEXA scans,
under the recommendations of the World Health Organization.
We also exclude the patients which had any clinical or radiological story of spinal surgery or traumatic spinal disease.
In the final,
from a total of 80 patients,
females and males,
we enrolled in this study 48 patients.
Imaging Techniques
DEXA scans with a Hologic Discovery QDR Series,
which the results of T-score and BMD () were obtained from L1 to L3 in an anteroposterior plane.
The patient was placed in a supine position,
with the knees elevated and the arms were placed near the body.
The age,
height,
weight,
BMI,
menopausal status in female and any history of disease was recorded.
(Fig.
2)
For the QCT we assessed all patients using a helical 64-channel CT scanner (Siemens Somatom Emotion Duo/6/16).
For the acquisition the patient also lied in supine position with the knees elevated to flatten the back,
and the patients’ arms were raised out of the field of view.
The BMD was determined using a ISNI software,
which calculated the BMD in mg ca-HA/ml.
The analysis was performed by delimitation of the trabecular and cortical bone in centre of mid-vertebral body.
BMD of each vertebra (L1-L3) was calculated,
and from these values the mean of BMD was determined,
note that only the values of trabecular bone were analysed in this study.
(Fig.
3)
Both studies were performed in the same day.
Statistical analysis
Bivariate correlation was used to assess the correlation between the QCT and BMD value,
and also between the QCT and T-score.
Beyond that,
the correlation coefficient was also determined (rs).
To better understand the correlation, scatter plots were also done.
ANOVAtest was performed to determine the mean of QCT for normal,
osteopenia and osteoporotic conditions.
All reported Pvalues are two-tailed,
with a Pvalue of 0.05 indicating statistical significance.
Analyses were performed with the use of SPSS statistics,
version 23.0.