Whole-body low-dose CT recognizes two distinct patterns of lytic lesions in multiple myeloma patients with different disease metabolism at PET/MRI

Abstract

We evaluated differences in density and 18 F-FDG PET/MRI features of lytic bone lesions (LBLs) identified by whole-body low-dose CT (WB-LDCT) in patients affected by newly diagnosed multiple myeloma (MM). In 18 MM patients, 135 unequivocal LBLs identified by WB-LDCT were characterized for inner density (negative or positive Hounsfield unit (HU)), where negative density (HU < 0) characterizes normal yellow marrow whereas positive HU correlates with tissue-like infiltrative pattern. The same LBLs were analyzed by 18 F-FDG PET/DWI-MRI, registering DWI signal with ADC and SUV max values. According to HU, 35 lesions had a negative density (− 56.94 ± 31.87 HU) while 100 lesions presented positive density (44.87 ± 23.89 HU). In seven patients, only positive HU LBLs were demonstrated whereas in eight patients, both positive and negative HU LBLs were detected. Intriguingly, in three patients (16%), only negative HU LBLs were shown. At 18 F-FDG PET/DWI-MRI analysis, negative HU LBLs presented low ADC values (360.69 ± 154.38 × 10 −6 mm 2 /s) and low SUV max values (1.69 ± 0.56), consistent with fatty marrow, whereas positive HU LBLs showed an infiltrative pattern, characterized by higher ADC (mean 868.46 ± 207.67 × 10 −6 mm 2 /s) and SUV max (mean 5.04 ± 1.94) values. Surprisingly, histology of negative HU LBLs documented infiltration by neoplastic plasma cells scattered among adipocytes. In conclusion, two different patterns of LBLs were detected by WB-LDCT in MM patients. Both types of lesions were indicative for active disease, although only positive HU LBL were captured by 18 F-FDG PET/DWI-MRI imaging, indicating that WB-LDCT adds specific information. Electronic supplementary material The online version of this article (10.1007/s00277-018-3555-7) contains supplementary material, which is available to authorized users.

Whole Body Low Dose Computed Tomography Using Third-Generation Dual-Source Multidetector With Spectral Shaping: Protocol Optimization and Literature Review

“… 4 Most recent studies, instead, employes a 120 kV protocol and a tube current between 30 and 100 mAs, to achieve an effective dose ranging between 2.7 mSv 9 and 29,5 mSv. 4 , 6 - 10 , 12 - 18 , 21 - 23 , 25 - 32 Other studies have been focused on a different approach based on low tube voltage (80 kV) and high current (200–230 mAs), generating an effective dose of about 4.5 mSv. 14 …”

“…4 Most recent studies, instead, employes a 120 kV protocol and a tube current between 30 and 100 mAs, to achieve an effective dose ranging between 2.7 mSv 9 and 29,5 mSv. 4,[6][7][8][9][10][12][13][14][15][16][17][18][21][22][23][25][26][27][28][29][30][31][32] Other studies have been focused on a different approach based on low tube voltage (80 kV) and high current (200-230 mAs), generating an effective dose of about 4.5 mSv. 14 Saravanabavaan et al exploited the potential of spectral shaping thanks to tin filter, in synergy with IR and automatic current modulation on a third-generation DSCT (Sn 100 kV, ref.…”

Whole-body magnetic resonance imaging (WBMRI) versus whole-body computed tomography (WBCT) for myeloma imaging and staging

“…Two different patterns of lytic bone lesions in MM were recently identified on WBLDCT [28]. The first pattern, with negative CT density values, had low 18 [F]-FDG-uptake on PET/CT and a low apparent diffusion coefficient (ADC) on MRI, which is consistent with fatty marrow.…”

Whole-Body Low-Dose Multidetector-Row CT in Multiple Myeloma: Guidance in Performing, Observing, and Interpreting the Imaging Findings

“…Lytic bone disease is the most common feature of MM, with up to 70-80% of patients having osteolytic lesions at diagnosis, and up to 90% developing lytic lesions during the disease evolution (Figure 5), leading to pathological fractures, brutal bone pain, and hypercalcemia [24,25]. MM-related osteolysis is represented by small, focal, low-density lesions of trabecular bone without sclerotic boundaries (unless prior treatment) (Figure 6); these lesions are morphologically defined in literature by IMWG criteria as typical punched-out osteolytic areas with a diameter greater than or equal to 5 mm without reactive sclerosis of the surrounding bone [26]. MM-related osteolysis is represented by small, focal, low-density lesions of trabecular bone without sclerotic boundaries (unless prior treatment) (Figure 6); these lesions are morphologically defined in literature by IMWG criteria as typical punched-out osteolytic areas with a diameter greater than or equal to 5 mm without reactive sclerosis of the surrounding bone [26].…”

“…MM-related osteolysis is represented by small, focal, low-density lesions of trabecular bone without sclerotic boundaries (unless prior treatment) (Figure 6); these lesions are morphologically defined in literature by IMWG criteria as typical punched-out osteolytic areas with a diameter greater than or equal to 5 mm without reactive sclerosis of the surrounding bone [26]. MM-related osteolysis is represented by small, focal, low-density lesions of trabecular bone without sclerotic boundaries (unless prior treatment) (Figure 6); these lesions are morphologically defined in literature by IMWG criteria as typical punched-out osteolytic areas with a diameter greater than or equal to 5 mm without reactive sclerosis of the surrounding bone [26]. CT is more sensitive compared to MRI in the detection of osteolytic bone lesions and better evaluates spinal stability in vertebral fractures; on the other hand, MRI is the reference standard method to detect bone marrow infiltration prior to bone fracture, as well as the various features of medullary involvement, ranging from focal and well circumscribed lesions to diffuse infiltration pattern; therefore, radiologists should always recommend MRI evaluation for those suspected small lesions that do not meet the strict abovementioned size criteria [27].…”