Use of marrow scintigraphy to confirm compensatory marrow rather than active myeloma

We present the case of a 40-year-old male with multiple myeloma for whom bone marrow scintigraphy was utilized to help differentiate between active bony myelomatous disease versus treated lesions with compensatory marrow uptake. This case demonstrates technetium (Tc-99m) sulfur colloid imaging as an inexpensive technique to quickly distinguish between active focal bone disease and reactive marrow

Best classifiers of infection status at week 1 and week 2 for all data.

<p>Classifiers of infection status over 1000 iterations are plotted, with frequency of classifier identification as the best in any given iteration indicated by size of the dot for that classifier. On day 7, the 5 best classifiers all occurred when <i>t₁ = 0</i>; that is, at a single timepoint SUR, with the single best classifier being <15 min after the administration of FDG. On day 14, all but one (<i>δ</i>SUV at <i>t₁</i> = 15 min and <i>t₂</i> = 40 min) of the 5 best classifiers of infection status were a single timepoint SUR, with the single best classifier being >85 min after the administration of FDG.</p

Confirmation of optimal 7 day diagnostic parameters.

<p>Left: Results illustrate the number of 1000 randomly-generated datasets in which the indicated timepoint after the administration of FDG exhibited maximum discrimination between the infected and uninfected experimental groups. Right: Results illustrate the proportion of “cut-off” ratios (surgical vs. non-surgical limb) that exhibited optimal discrimination at the alternative timepoints shown. Note that >850 of 1000 “iterations” found the optimum timepoint to be 11 minutes after administration of FDG (left) and that the optimal SUR cutoff in the majority of these was ∼1.27.</p

Representative X-ray and FDG-PET images.

<p>Representative X-rays of the surgical site are shown for infected and uninfected rabbits as a function of time after surgery. Summed FDG-PET images below each X-ray illustrate uptake in both the surgical (R, surgical site illustrated by bracket) and non-surgical limbs (L) in an infected and an uninfected animal. “Regions of interest” (ROIs) used for measurement of SUV in each limb are illustrated by the circles.</p

Uptake of FDG over time.

<p>Uptake in the surgical (top) vs non-surgical limb (bottom) is shown for the infected and uninfected control groups as a function of time after the administration of FDG. Results for each group obtained 7 and 14 days after surgery are shown as the average SUV_max (solid line) ± one standard deviation from the mean (shaded regions). Results represent the averages ± standard deviations obtained after combining all experimental animals in the 1^st and 2^nd trials (see text).</p

Quantitative description of infection status in each experimental group.

<p>Quantitative histological and radiological analyses were done as previously described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041863#pone.0041863-Smeltzer1" target="_blank">[14]</a> with the results reported as the average ± the standard deviation for the infected (Inf) and uninfected (Cont) groups. Histological results were obtained only at the completion of the experiment while X-ray studies were performed at both 7 and 14 days.</p

Identification of optimal 14 day diagnostic parameters.

<p>Left: Results illustrate the number of 1000 randomly-generated datasets in which the indicated timepoint after the administration of FDG exhibited maximum discrimination between the infected and uninfected experimental groups. Right: Results illustrate the proportion of “cut-off” ratios (surgical vs. non-surgical limb) that exhibited optimal discrimination at the alternative timepoints shown. Note that the number of “iterations” in which the greatest discrimination was observed were comparable when the assay was done 57 or 85 minutes after the administration of FDG and that the optimal SUR cutoff differed between these two timepoints.</p

Diagnostic parameters as a function of FDG-PET evaluation model.

*<p>Model 1: ratio @ 11 mins ≥1.27 classified as infected for week 1 measures.</p>†<p>Model 2: ratio @ 85 mins ≥1.45 classified as infected for week 2 measures.</p>$<p>Both: ratio @ 11 mins ≥1.27 or ratio @ 85 mins ≥1.45 classified as infected.</p>#<p><i>c</i> is the cell count and <i>m</i> is the appropriate marginal total.</p