Improved MDCT monitoring of pelvic myeloma bone disease through the use of a novel longitudinal bone subtraction post-processing algorithm.
PURPOSE
To evaluate the diagnostic performance of a novel CT post-processing software that generates subtraction maps of baseline and follow-up CT examinations in the course of myeloma bone lesions.


MATERIALS AND METHODS
This study included 61 consecutive myeloma patients who underwent repeated whole-body reduced-dose MDCT at our institution between November 2013 and June 2015. CT subtraction maps classified a progressive disease (PD) vs. stable disease (SD)/remission. Bone subtraction maps (BSMs) only and in combination with 1-mm (BSM+) source images were compared with 5-mm axial/MPR scans.


RESULTS
Haematological response categories at follow-up were: complete remission (n = 9), very good partial remission (n = 2), partial remission (n = 17) and SDh (n = 19) vs. PDh (n = 14). Five-millimetre CT scan yielded PD (n = 14) and SD/remission (n = 47) whereas bone subtraction + 1-mm axial scans (BSM+) reading resulted in PD (n = 18) and SD/remission (n = 43). Sensitivity/ specificity/accuracy for 5-mm/1-mm/BSM(alone)/BSM + in "lesion-by-lesion" reading was 89.4 %/98.9 %/98.3 %/ 99.5 %; 69.1 %/96.9 %/72 %/92.1 % and 83.8 %/98.4 %/92.1 %/98.3 %, respectively. The use of BSM+ resulted in a change of response classification in 9.8 % patients (n = 6) from SD to PD.


CONCLUSION
BSM reading is more accurate for monitoring myeloma compared to axial scans whereas BSM+ yields similar results with 1-mm reading (gold standard) but by significantly reduced reading time.


KEY POINTS
• CT evaluation of myeloma bone disease using a longitudinal bone subtraction post-processing algorithm. • Bone subtraction post-processing algorithm is more accurate for assessment of therapy. • Bone subtraction allowed improved and more efficient detection of myeloma bone lesions. • Post-processing tool demonstrating a change in response classification in 9.8 % patients (all showing PD). • Reading time could be substantially shortened as compared to regular CT assessment.
['Horger|Marius|M|', 'Thaiss|Wolfgang M|WM|', 'Ditt|Hendrik|H|', 'Weisel|Katja|K|', 'Fritz|Jan|J|', 'Nikolaou|Konstantin|K|', 'Liao|Shu|S|', 'Kloth|Christopher|C|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D000465:Algorithms D005260:Female D006801:Humans D007090:Image Interpretation, Computer-Assisted D008297:Male D008875:Middle Aged D061330:Multidetector Computed Tomography D009101:Multiple Myeloma D009367:Neoplasm Staging D010384:Pelvic Bones D012372:ROC Curve D015203:Reproducibility of Results D012189:Retrospective Studies D012984:Software D013382:Subtraction Technique D051598:Whole Body Imaging
Bone subtraction maps CT imaging Lytic bone lesions Multiple myeloma Pelvic bones