Whole-body low-dose multidetector row-CT in the diagnosis of multiple myeloma: an alternative to conventional radiography

Effectiveness of low dose computed tomography to detect fractures in paediatric suspected physical abuse: a systematic review

PURPOSE

The skeletal survey X-ray series is the current 'gold standard' when investigating suspected physical abuse (SPA) of children, in addition to a non-contrast computed tomography (CT) brain scan. This systematic literature review synthesised findings of published research to determine if low dose computed tomography (LDCT) could detect subtle fractures and therefore replace the skeletal survey X-ray series in the investigation of SPA in children aged under 3 years.

METHODS

Five electronic databases and grey literature were systematically searched from their inception to 28 April 2022. Primary studies were included where the population comprised paediatric patients up to 16 years and LDCT was used to detect fractures associated with SPA. Studies involving imaging investigations of the head, standard dose CT examinations or accidental trauma were excluded.

RESULTS

Three studies met the inclusion criteria, all of which were case series. These studies did not report many of the criteria required to compare the accuracy of LDCT to X-ray, i.e. they did not meet the criteria for a diagnostic accuracy test. Therefore, it is difficult to conclude from the case series if LDCT is accurate enough to replace X-rays.

CONCLUSION

Due to the gap in current literature, a phantom study and subsequent post-mortem CT study are recommended as the primary investigative methods to assess the ability of low-dose CT to identify the subtle fractures associated with SPA and to calculate how low the achievable CT dose can be.

GA-Net: A geographical attention neural network for the segmentation of body torso tissue composition

PURPOSE

Body composition analysis (BCA) of the body torso plays a vital role in the study of physical health and pathology and provides biomarkers that facilitate the diagnosis and treatment of many diseases, such as type 2 diabetes mellitus, cardiovascular disease, obstructive sleep apnea, and osteoarthritis. In this work, we propose a body composition tissue segmentation method that can automatically delineate those key tissues, including subcutaneous adipose tissue, skeleton, skeletal muscle tissue, and visceral adipose tissue, on positron emission tomography/computed tomography scans of the body torso.

METHODS

To provide appropriate and precise semantic and spatial information that is strongly related to body composition tissues for the deep neural network, first we introduce a new concept of the body area and integrate it into our proposed segmentation network called Geographical Attention Network (GA-Net). The body areas are defined following anatomical principles such that the whole body torso region is partitioned into three non-overlapping body areas. Each body composition tissue of interest is fully contained in exactly one specific minimal body area. Secondly, the proposed GA-Net has a novel dual-decoder schema that is composed of a tissue decoder and an area decoder. The tissue decoder segments the body composition tissues, while the area decoder segments the body areas as an auxiliary task. The features of body areas and body composition tissues are fused through a soft attention mechanism to gain geographical attention relevant to the body tissues. Thirdly, we propose a body composition tissue annotation approach that takes the body area labels as the region of interest, which significantly improves the reproducibility, precision, and efficiency of delineating body composition tissues.

RESULTS

Our evaluations on 50 low-dose unenhanced CT images indicate that GA-Net outperforms other architectures statistically significantly based on the Dice metric. GA-Net also shows improvements for the 95% Hausdorff Distance metric in most comparisons. Notably, GA-Net exhibits more sensitivity to subtle boundary information and produces more reliable and robust predictions for such structures, which are the most challenging parts to manually mend in practice, with potentially significant time-savings in the post hoc correction of these subtle boundary placement errors. Due to the prior knowledge provided from body areas, GA-Net achieves competitive performance with less training data. Our extension of the dual-decoder schema to TransUNet and 3D U-Net demonstrates that the new schema significantly improves the performance of these classical neural networks as well. Heatmaps obtained from attention gate layers further illustrate the geographical guidance function of body areas for identifying body tissues.

CONCLUSIONS

(i) Prior anatomic knowledge supplied in the form of appropriately designed anatomic container objects significantly improves the segmentation of bodily tissues. (ii) Of particular note are the improvements achieved in the delineation of subtle boundary features which otherwise would take much effort for manual correction. (iii) The method can be easily extended to existing networks to improve their accuracy for this application.

Myeloma bone disease imaging on a 1st-generation clinical photon-counting detector CT vs. 2nd-generation dual-source dual-energy CT

OBJECTIVE

Subjective and objective image quality comparison of bone microstructure and disease-related abnormalities in multiple myeloma patients using a 1st-generation dual-source photon-counting detector CT(DS-PCD-CT) and a 2nd-generation dual-source dual-energy (energy-integrating detector) CT (DS-EID-CT).

METHODS

Fifty multiple myeloma patients (mean age 67.7 ± 10.9 years,16 females) were prospectively enrolled. Unenhanced whole-body CTs were clinically indicated and performed on DS-EID-CT and DS-PCD-CT (median time difference: 12 months). DS-PCD-CT was performed in Quantumplus UHR mode and DS-EID-CT was performed using dual-energy mode. DS-PCD-CT kernel was set at Br64 with Quantum iterative reconstruction strength Q1; for DS-EID-CT a comparable I70f kernel with SAFIRE iterative reconstruction strength 1 was used. Two independent radiologists assessed image quality subjectively using a 5-point Likert scale considering delineation and sharpness of trabecular bone and lytic bone lesions in the spine and pelvic bones. Additionally, ImageJ was used for quantification of bony septa inside the cancellous bone and through or the edges of osteolysis.

RESULTS

Overall quality as well as detectability and sharpness in the delineation of lytic bone lesions were superior for DS-PCD-CT compared with DS-EID-CT (p < 0.0001). The inter-reader agreement for subjective image quality readings showed excellent consistency(α = 94.2-98.8). CTDI and DLP mean values for DS-PCD-CT and DS-EID-CT were 1107.4 ± 247.6 mGy*cm and 8.2 ± 1.8 mGy vs. 1344.3 ± 204.6 mGy*cm and 10.1 ± 1.9 mGy. The quantitative metric for bone microstructure in the femoral head showed significantly better visualization of trabeculae in DS-PCD-CT compared with DS-EID-CT (p < 0.0001). Quantitative analyses of edge sharpness of osteolysis showed significant steeper edges for DS-PCD-CT (p < 0.0001).

CONCLUSION

DS-PCD-CT significantly improves spatial resolution of bony microstructure and lytic bone lesions compared to DS-EID-CT.

KEY POINTS

• Application of photon-counting detector CT is superior to dual-source dual-energy integrating detector in clinical workup of multiple myeloma patients. • Compared to energy integrating detectors, photon-counting detectors significantly increase the spatial resolution of bone microstructure including disease-related lytic bone lesions in patients with multiple myeloma.

Computed tomography with adjusted dose for body mass index may be superior to whole-body radiography especially in elderly patients with multiple myeloma

BACKGROUND

Whole-body skeletal radiography has traditionally been used in the management of multiple myeloma for defining treatment strategies. For several reasons, radiography has been replaced by computed tomography (CT) covering the same regions.

PURPOSE

To evaluate the body mass index (BMI) adjusted effective radiation dose from two different methods of whole-body radiologic imaging for multiple myeloma assessment.

MATERIAL AND METHODS

The current investigation analyses the dose to patients resulting from the two methods, conventional radiography supplemented with tomosynthesis (203 examinations) and CT (264 examinations). All patients subject to myeloma staging for 4.5 years were included in the study. Exposure parameters were collected from the PACS and conversion factors were calculated using the software packages PCXMC and VirtualDose enabling the calculation of the effective dose to each patient based on BMI. The Mann-Whitney U test was used for comparisons between groups.

RESULTS

Patients were subject to a median effective dose of 2.5 mSv for conventional radiography and 5.1 mSv for CT, a statistically significant difference.

CONCLUSION

The effective dose for whole-body CT in assessing multiple myeloma is twice as high as for whole-body skeletal survey with modern digital radiography, but at a low level and considerably less than the levels quoted in the earlier studies of ∼30 mSv when the technique was first explored.

A deep learning algorithm for detecting lytic bone lesions of multiple myeloma on CT

BACKGROUND

Whole-body low-dose CT is the recommended initial imaging modality to evaluate bone destruction as a result of multiple myeloma. Accurate interpretation of these scans to detect small lytic bone lesions is time intensive. A functional deep learning) algorithm to detect lytic lesions on CTs could improve the value of these CTs for myeloma imaging. Our objectives were to develop a DL algorithm and determine its performance at detecting lytic lesions of multiple myeloma.

METHODS

Axial slices (2-mm section thickness) from whole-body low-dose CT scans of subjects with biochemically confirmed plasma cell dyscrasias were included in the study. Data were split into train and test sets at the patient level targeting a 90%/10% split. Two musculoskeletal radiologists annotated lytic lesions on the images with bounding boxes. Subsequently, we developed a two-step deep learning model comprising bone segmentation followed by lesion detection. Unet and "You Look Only Once" (YOLO) models were used as bone segmentation and lesion detection algorithms, respectively. Diagnostic performance was determined using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Forty whole-body low-dose CTs from 40 subjects yielded 2193 image slices. A total of 5640 lytic lesions were annotated. The two-step model achieved a sensitivity of 91.6% and a specificity of 84.6%. Lesion detection AUROC was 90.4%.

CONCLUSION

We developed a deep learning model that detects lytic bone lesions of multiple myeloma on whole-body low-dose CTs with high performance. External validation is required prior to widespread adoption in clinical practice.

Imaging CXCR4 receptors expression for staging multiple myeloma by using 68Ga-Pentixafor PET/CT: comparison with 18F-FDG PET/CT

OBJECTIVES

68Ga-Pentixafor positron emission tomography (PET) imaging targets CXCR4 expression which is overexpressed in multiple myeloma (MM). In this study, we evaluated the diagnostic utility of 68Ga-Pentixafor PET/CT for imaging CXCR4 expression in MM and compared results with 18F-fluorodeoxyglucose (18F-FDG) PET/CT.

METHODS

34 (21M; 13F; median age = 57.5 years) treatment naive multiple myeloma patients were recruited. All the patients underwent 18F-FDG PET/CT and 68Ga-Pentixafor PET/CT imaging. Freshly prepared 68Ga-Pentixafor (148-185 MBq) was injected intravenously and whole-body PET/CT (low-dose CT) was acquired at 1 h post-injection. The pattern of uptake (diffuse, focal or mixed) and the mean SUVmax value of all the lesions (when lesions were ≤5) or of the five most tracer avid lesions (when lesions was >5) were evaluated. Tumor to background ratio (TBRmax) was calculated for both the tracers. Durie Salmon plus staging (DSPS) was used for disease staging on PET and the results were compared with International staging system (ISS).

RESULTS

68Ga-Pentixafor PET/CT showed higher disease extent than seen on 18F-FDG PET/CT in 23/34 patients (68.0%), lesser disease extent in 2/34 (6%) and similar disease extent in 9/34 (26%) patients. Significantly (p < 0.001) higher TBRmax values (5.7; IQR 8.8) were observed on 68Ga-Pentixafor PET/CT as compared to 18F-FDG PET/CT values (2.9; IQR = 4.0). Both the techniques detected extramedullary lesions in six patients. On the other hand, 68Ga-Pentixafor detected medullary lesions in five, whereas, 18F-FDG PET in three patients. Further, only 68Ga-Pentixafor TBRmax correlated significantly (ρ = 0.421; 0.013) with bone marrow plasma cell percentage. 68Ga-Pentixafor PET upstaged more number (9/29) of patients as compared to (4/29) 18F-FDG PET imaging. On the other hand, 18F-FDG PET down-staged 9/29, whereas 68Ga-Pentixafor PET downstaged only 3/29 patients.

CONCLUSION

68Ga-Pentixafor PET/CT evaluated the whole-body disease burden of CXCR4 receptors non-invasively which is not possible by tissue sampling methods. This novel PET tracer has also implication for disease staging. Dual 68Ga-Pentixafor/18F-FDG PET/CT imaging may help in determining the tumor heterogeneity in MM.

ADVANCES IN KNOWLEDGE

This CXCR4 targeting PET tracer has a promising role in the development of CXCR4 targeting theranostics and also for response assessment to these therapies including the conventional treatment.

Newly Diagnosed Multiple Myeloma Patients with Skeletal-Related Events and Abnormal MRI Pattern Have Poor Survival Outcomes: A Prospective Study on 370 Patients

Contemporary information is sparse on the frequency of skeletal-related events (SREs) in multiple myeloma (MM) patients at a population-based level in the era of novel agents. In this context, we conducted this single-center, prospective, observational study to determine the incidence of SREs among newly diagnosed MMs (NDMM) and to explore the possible correlations with disease characteristics, imaging finding, and patient prognosis. A total of 370 patients with available baseline MRIs were included. Among them, 208 (56%) presented with at least one SRE at diagnosis. Fractures were the most common reported SREs (48%). The incidence of SREs at diagnosis was higher in patients with osteolytic lesions, abnormal MRI pattern, hypercalcemia, and at least 60% bone marrow infiltration by plasma cells. Importantly, the patients with normal MRI pattern, who did not present with SREs at diagnosis, had statistically significant improved median OS in comparison with the patients who had abnormal MRI patterns and/or the presence of SREs at diagnosis (9.3 vs. 6.6 years, p = 0.048). Our data, which represent one of a few systematic reports on the incidence and characteristics of SREs in the era of novel agents, was indicative of a high incidence of SREs at the time of MM diagnosis. Early detection of myeloma bone disease and tailored patient management are essential to optimize patient outcomes.

A prospective study of Skeletal survey versus Low-dose whole-body CT for Osteolytic lesions in Multiple Myeloma

Whole-body low-dose CT (WBLDCT) is recommended over classical skeletal surveys (CSS) for investigating bone disease in multiple myeloma (MM) based on retrospective studies. No prospective studies with serial follow-up scans exist.

OBJECTIVE

To compare WBLDCT to CSS for identifying progressive bone disease in MM in a prospective setting.

METHODS

Ninety-six patients with MM at Odense University Hospital and Stavanger Hospital were followed for up to four years. Patients were scanned with WBLDCT and CSS every year for the first two years and every six months thereafter or at suspicion of progression.

RESULTS

Nineteen cases of progressive bone disease were found using WBLDCT vs eight cases using CSS (p < 0.001). All cases of progressive bone disease using CSS were also identified by WBLDCT. Progression not found by CSS was primarily in the spine, sternum, and pelvis. Of the 19 cases, five patients had progressive bone disease only without other criteria for clinical progression. WBLDCT consistently identified more bone lesions per patient, 8.2 CI(6.8;9.6) vs CSS, 3.6 CI(2.7;4.5).

CONCLUSION

WBLDCT outperformed CSS for finding progressive bone disease and osteolytic lesions. More new lesions were found during follow-up by WBLDCT than CSS. Using CSS for lytic lesions will underestimate progression rates. Our data offer prospective evidence for the current recommendation using WBLDCT for skeletal evaluations in patients with multiple myeloma.

Radiation exposure and establishment of diagnostic reference levels of whole-body low-dose CT for the assessment of multiple myeloma with second- and third-generation dual-source CT

BACKGROUND

In the assessment of diseases causing skeletal lesions such as multiple myeloma (MM), whole-body low-dose computed tomography (WBLDCT) is a sensitive diagnostic imaging modality, which has the potential to replace the conventional radiographic survey.

PURPOSE

To optimize radiation protection and examine radiation exposure, and effective and organ doses of WBLDCT using different modern dual-source CT (DSCT) devices, and to establish local diagnostic reference levels (DRL).

MATERIAL AND METHODS

In this retrospective study, 281 WBLDCT scans of 232 patients performed between January 2017 and April 2020 either on a second- (A) or third-generation (B) DSCT device could be included. Radiation exposure indices and organ and effective doses were calculated using a commercially available automated dose-tracking software based on Monte-Carlo simulation techniques.

RESULTS

The radiation exposure indices and effective doses were distributed as follows (median, interquartile range): (A) second-generation DSCT: volume-weighted CT dose index (CTDI_vol) 1.78 mGy (1.47-2.17 mGy); dose length product (DLP) 282.8 mGy·cm (224.6-319.4 mGy·cm), effective dose (ED) 1.87 mSv (1.61-2.17 mSv) and (B) third-generation DSCT: CTDI_vol 0.56 mGy (0.47-0.67 mGy), DLP 92.0 mGy·cm (73.7-107.6 mGy·cm), ED 0.61 mSv (0.52-0.69 mSv). Radiation exposure indices and effective and organ doses were significantly lower with third-generation DSCT (P < 0.001). Local DRLs could be set for CTDI_vol at 0.75 mGy and DLP at 120 mGy·cm.

CONCLUSION

Third-generation DSCT requires significantly lower radiation dose for WBLDCT than second-generation DSCT and has an effective dose below reported doses for radiographic skeletal surveys. To ensure radiation protection, DRLs regarding WBLDCT are required, where our locally determined values may help as benchmarks.

Imaging for Plasma Cell Dyscrasias: What, When, and How?

Imaging plays a vital role in the diagnosis, response assessment, and follow-up of patients with plasma cell bone disease. The radiologic diagnostic paradigm has thus far evolved with developing technology and availability of better imaging platforms; however, the skewed availability of these imaging modalities in developed vis-à-vis the developing countries along with the lack of uniformity in reporting has led to a consensus on the imaging criteria for diagnosing and response assessment in plasma cell dyscrasia. Therefore, it is imperative for not only the radiologists but also the treating oncologist to be aware of the criteria and appropriate imaging modality to be used in accordance with the clinical question. The review will allow the treating oncologist to answer the following questions on the diagnostic, prognostic, and predictive abilities of various imaging modalities for plasma cell dyscrasia: a) What lesions can look like multiple myeloma (MM) but are not?; b) Does the patient have MM? To diagnose MM in a high-risk SMM patient with clinical suspicion, which modality should be used and why?; c) Is the patient responding to therapy on follow-up imaging once treatment is initiated?; d) To interpret commonly seen complications post-therapy, when is it a disease and when is the expected sequel to treatment? Fractures, red marrow reconversion?; and e) When is the appropriate time to flag a patient for further workup when interpreting MRI spine done for back pain in the elderly? How do we differentiate between commonly seen osteoporosis-related degenerative spine versus marrow infiltrative disorder?

Modern radiographic imaging in multiple myeloma, what is the minimum requirement?

Imaging innovations offer useful techniques applicable to many oncology specialties. Treatment advances in the field of multiple myeloma (MM) have increased the need for accurate diagnosis, particularly in the bone marrow, which is an essential component in myeloma-defining criteria. Modern imaging identifies osteolytic lesions, distinguishes solitary plasmacytoma from MM, and evaluates the presence of extramedullary disease. Furthermore, imaging is increasingly valuable in post-treatment response assessment. Detection of minimal residual disease after therapy carries prognostic implications and influences subsequent treatment planning. Whole-body low-dose Computed Tomography is now recommended over the conventional skeletal survey, and more sophisticated functional imaging methods, such as ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography , and diffusion-weighted Magnetic Resonance Imaging are proving effective in the assessment and monitoring of MM disease. This review focuses on understanding indications and advantages of these imaging modalities for diagnosing and managing myeloma.

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

Myeloma-associated bone disease (MBD) develops in about 80-90% of patients and severely affects their quality of life, as it accounts for the majority of mortality and morbidity. Imaging in multiple myeloma (MM) and MBD is of utmost importance in order to detect bone and bone marrow lesions as well as extraosseous soft-tissue masses and complications before the initiation of treatment. It is required for determination of the stage of disease and aids in the assessment of treatment response. Whole-body low-dose computed tomography (WBLDCT) is the key modality to establish the initial diagnosis of MM and is now recommended as reference standard procedure for the detection of lytic destruction in MBD. In contrast, whole-body magnetic resonance imaging (WBMRI) has higher sensitivity for the detection of focal and diffuse plasma cell infiltration patterns of the bone marrow and identifies them prior to osteolytic destruction. It is recommended for the evaluation of spinal and vertebral lesions, while functional, diffusion-weighted MRI (DWI-MRI) is a promising tool for the assessment of treatment response. This review addresses the current improvements and limitations of WBCT and WBMRI for diagnosis and staging in MM, underlining the fact that both modalities offer complementary information. It further summarizes the corresponding radiological findings and novel technological aspects of both modalities.

Whole-body Computed Tomography Versus Dual Energy X‑ray Absorptiometry for Assessing Heterotopic Ossification in Fibrodysplasia Ossificans Progressiva

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder that leads to heterotopic ossification (HO), resulting in progressive restriction of physical function. In this study, low-dose, whole-body computed tomography (WBCT) and dual energy X-ray absorptiometry (DXA) were evaluated to determine the preferred method for assessing total body burden of HO in patients with FOP. This was a non-interventional, two-part natural history study in patients with FOP (NCT02322255; date of registration: December 2014). In Part A (described here), WBCT and DXA scans were individually assessed for HO presence and severity across 15 anatomical regions. All images were independently reviewed by an expert imaging panel. Ten adult patients were enrolled across four sites. The sensitivity to HO presence and severity varied considerably between the two imaging modalities, with WBCT demonstrating HO in more body regions than DXA (76/138 [55%] versus 47/113 [42%]) evaluable regions). Inability to evaluate HO presence, due to overlapping body regions (positional ambiguity), occurred less frequently by WBCT than by DXA (mean number of non-evaluable regions per scan 1.2 [standard deviation: 1.5] versus 2.4 [1.4]). Based on the increased sensitivity and decreased positional ambiguity of low-dose WBCT versus DXA in measuring HO in patients with FOP, low-dose WBCT was chosen as the preferred imaging for measuring HO. Therefore, low-dose WBCT was carried forward to Part B of the natural history study, which evaluated disease progression over 36 months in a larger population of patients with FOP.

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

Multiple myeloma is a hematological malignancy of plasma cells usually detected due to various bone abnormalities on imaging and rare extraosseous abnormalities. The traditional approach for disease detection was based on plain radiographs, showing typical lytic lesions. Still, this technique has many limitations in terms of diagnosis and assessment of response to treatment. The new approach to assess osteolytic lesions in patients newly diagnosed with multiple myeloma is based on total-body low-dose CT. The purpose of this paper is to suggest a guide for radiologists in performing and evaluating a total-body low-dose CT in patients with multiple myeloma, both newly-diagnosed and in follow-up (pre and post treatment).

Ultra-Low-Dose Whole-Body Computed Tomography Protocol Optimization for Patients With Plasma Cell Disorders: Diagnostic Accuracy and Effective Dose Analysis From a Reference Center

BACKGROUND

The whole-body low-dose CT (WBLDCT) is the first-choice imaging technique in patients with suspected plasma cell disorder to assess the presence of osteolytic lesions. We investigated the performances of an optimized protocol, evaluating diagnostic accuracy and effective patient dose reduction using a latest generation scanner.

METHODS AND MATERIALS

Retrospective study on 212 patients with plasma cell disorders performed on a 256-row CT scanner. First, WBLDCT examinations were performed using a reference protocol with acquisition parameters obtained from literature. A phantom study was performed for protocol optimization for subsequent exams to minimize dose while maintaining optimal diagnostic accuracy. Images were analyzed by three readers to evaluate image quality and to detect lesions. Effective doses (E) were evaluated for each patient considering the patient dimensions and the tube current modulation.

RESULTS

A similar, very good image quality was observed for both protocols by all readers with a good agreement at repeated measures ANOVA test (p>0.05). An excellent inter-rater agreement for lesion detection was achieved obtaining high values of Fleiss' kappa for all the districts considered (p<0.001). The optimized protocol resulted in a 56% reduction of median DLP (151) mGycm, interquartile range (IQR) 128-188 mGycm vs. 345 mGycm, IQR 302-408 mGycm), of 60% of CTDIvol (2.2 mGy, IQR 1.9-2.7 mGy vs. 0.9 mGy, IQR 0.8-1.2 mGy). The median E value was about 2.6 mSv (IQR 1.7-3.5 mSv) for standard protocol and about 1.5 mSv (IQR 1.4-1.7 mSv) for the optimized one. Dose reduction was statistically significant with p<0.001.

CONCLUSIONS

Protocol optimization makes ultra-low-dose WBLDCT feasible on latest generation CT scanners for patients with plasma cell disorders with effective doses inferior to conventional skeletal survey while maintaining excellent image quality and diagnostic accuracy. Dose reduction is crucial in such patients, as they are likely to undergo multiple whole-body CT scans during follow-up.

Deep Learning Algorithm for Simultaneous Noise Reduction and Edge Sharpening in Low-Dose CT Images: A Pilot Study Using Lumbar Spine CT

Objective

The purpose of this study was to assess whether a deep learning (DL) algorithm could enable simultaneous noise reduction and edge sharpening in low-dose lumbar spine CT.

Materials and Methods

This retrospective study included 52 patients (26 male and 26 female; median age, 60.5 years) who had undergone CT-guided lumbar bone biopsy between October 2015 and April 2020. Initial 100-mAs survey images and 50-mAs intraprocedural images were reconstructed by filtered back projection. Denoising was performed using a vendor-agnostic DL model (ClariCT.AI™, ClariPI) for the 50-mAS images, and the 50-mAs, denoised 50-mAs, and 100-mAs CT images were compared. Noise, signal-to-noise ratio (SNR), and edge rise distance (ERD) for image sharpness were measured. The data were summarized as the mean ± standard deviation for these parameters. Two musculoskeletal radiologists assessed the visibility of the normal anatomical structures.

Results

Noise was lower in the denoised 50-mAs images (36.38 ± 7.03 Hounsfield unit [HU]) than the 50-mAs (93.33 ± 25.36 HU) and 100-mAs (63.33 ± 16.09 HU) images (p < 0.001). The SNRs for the images in descending order were as follows: denoised 50-mAs (1.46 ± 0.54), 100-mAs (0.99 ± 0.34), and 50-mAs (0.58 ± 0.18) images (p < 0.001). The denoised 50-mAs images had better edge sharpness than the 100-mAs images at the vertebral body (ERD; 0.94 ± 0.2 mm vs. 1.05 ± 0.24 mm, p = 0.036) and the psoas (ERD; 0.42 ± 0.09 mm vs. 0.50 ± 0.12 mm, p = 0.002). The denoised 50-mAs images significantly improved the visualization of the normal anatomical structures (p < 0.001).

Conclusion

DL-based reconstruction may enable simultaneous noise reduction and improvement in image quality with the preservation of edge sharpness on low-dose lumbar spine CT. Investigations on further radiation dose reduction and the clinical applicability of this technique are warranted.

Whole Body Low Dose Computed Tomography (WBLDCT) Can Be Comparable to Whole-Body Magnetic Resonance Imaging (WBMRI) in the Assessment of Multiple Myeloma

Aim of the study is to compare the agreement between whole-body low-dose computed tomography (WBLDCT) and magnetic resonance imaging (WBMRI) in the evaluation of bone marrow involvement in patients with multiple myeloma (MM). Patients with biopsy-proven MM, who underwent both WBLDCT and WBMRI were retrospectively enrolled. After identifying the presence of focal bone involvement (focal infiltration pattern), the whole skeleton was divided into five anatomic districts (skull, spine, sternum and ribs, pelvis, and limbs). Patients were grouped according to the number and location of the lytic lesions (<5, 5-20, and >20) and Durie and Salmon staging system. The agreement between CT and MRI regarding focal pattern, staging, lesion number, and distribution was assessed using the Cohen Kappa statistics. The majority of patients showed focal involvement. According to the distribution of the focal lesions and Durie Salmon staging, the agreement between CT and MRI was substantial or almost perfect (all κ > 0.60). The agreement increased proportionally with the number of lesions in the pelvis and spine (κ = 0.373 to κ = 0.564, and κ = 0.469-0.624), while for the skull the agreement proportionally decreased without reaching a statistically significant difference (p > 0.05). In conclusion, WBLDCT showed an almost perfect agreement in the evaluation of focal involvement, staging, lesion number, and distribution of bone involvement in comparison with WBMRI.

Whole-body low-dose computed tomography (WBLDCT) in staging and re-staging of multiple myeloma

The objective of this study is to evaluate the prognostic features of multiple myeloma (MM) using whole-body low-dose computed tomography (WBLDCT). One hundred three patients with biopsy-proven MM who underwent WBLDCT were retrospectively enrolled. The evolution of osteolytic lesions overtime was performed by measuring the maximum axial diameter at the baseline (T₀) and the end of follow-up (T_e), by using a cut-off value of 10 mm. The location and dimension of up to three lesions were registered. The time-to-fracture (TTF) was recorded. Sixty-three percent of patients presented a focal pattern, 22% a diffuse pattern, and 15% a combined one. Seventy-two percent of patients with lesions ≤ 10 mm presented stability, 27% a dimensional increase, and 1% a decrease. Patients with lesions >10 mm showed a statistically significant difference regarding the mean difference of axial diameter between T₀ and T_e (p = 0.015). Patients with lesions >10 mm showed an odds ratio (OR) of 29.8 (95%CIs 3.8-230.5) to develop at least one fracture. Mean TTF was significantly lower in patients with lesions >10 mm in comparison with lesions ≤ 10 mm (9 ± 3 vs 23 ± 7 months, respectively, p = 0.011). WBLDCT represents a reliable imaging-based tool for proper management of MM patients, showing that diffuse form or small lytic lesions may deserve a less frequent follow-up.

Whole-Body Low-Dose CT in Multiple Myeloma: Diagnostic Value of Appendicular Medullary Patterns of Attenuation

OBJECTIVE. The purpose of this article is to analyze whole-body low-dose CT-detected appendicular medullary patterns of attenuation in patients with newly diagnosed multiple myeloma and to determine the diagnostic performance of whole-body low-dose CT in detecting diffuse marrow infiltration. MATERIALS AND METHODS. A total of 76 patients with myeloma who underwent whole-body low-dose CT and spinal MRI at initial assessment were retrospectively analyzed. The medullary cavities of femurs and humeri were evaluated qualitatively and quantitatively on CT. Medullary attenuation and SD-to-mean attenuation ratio were recorded for each long bone. The pattern of marrow involvement on spinal MRI was used as reference. The chi-square test was used to evaluate the relationship between the CT-based appendicular medullary cavity pattern and the MRI pattern, and ROC analysis was performed to assess the diagnostic accuracy of CT attenuation measurements for the differentiation between diffuse and mixed CT-based appendicular medullary cavity patterns. RESULTS. Medullary attenuation differed significantly among mixed, nodular, and diffuse CT-based appendicular medullary cavity patterns in the femurs (mean, 34.23 HU and range, 15-61 HU; mean, 66.26 HU and range, 26-104 HU; mean, 92.80 HU and range, 53-127 HU, respectively) and humeri (mean, 22.18 HU and range, 9-41; mean, 61.18 HU and range, 23-93 HU; mean, 77.50 and range, 25-105 HU, respectively). To discriminate between diffuse and mixed CT-based appendicular medullary cavity patterns, optimal cutoff attenuation values were 63 HU (sensitivity, 97.7%; specificity, 100.0%) for the femurs, and 52 HU (sensitivity, 97.4%; specificity, 100.0%) for the humeri. A total of 24 of 30 (80.0%) patients with a diffuse MRI pattern showed a diffuse CT-based appendicular medullary cavity pattern on whole-body low-dose CT, and all patients with a diffuse CT-based appendicular medullary cavity pattern also showed a diffuse pattern on MRI. CONCLUSION. According to analysis of peripheral medullary patterns of attenuation, whole-body low-dose CT can identify patients with multiple myeloma with diffuse marrow involvement.

Adaptive statistical iterative reconstruction for computed tomography of the spine

INTRODUCTION

The utility of evaluating a sagittal view of CT of the spine is well-known. In many clinical cases, the sagittal view includes noise generated from surrounding objects and may degrade the image quality. Iterative reconstruction (IR) techniques are useful for noise reduction; however, they can reduce spatial resolution. The aim of this study was to evaluate the effectiveness of the adaptive statistical iterative reconstruction (ASiR) for generating sagittal CT images of the spine when compared to filtered back projection (FBP).

METHODS

The image quality of clinical images from 25 patients were subjectively assessed. Three radiologists rated spatial resolution, image noise, and overall image quality using a five-point scale. For objective assessment, z-direction modulation transfer function (z-MTF) was measured using a custom-made phantom. Additionally, z-axis noise power spectrum (z-NPS) was measured using a water phantom. An improved adaptive statistical iterative reconstruction algorithm called ASiR-V was used in this study. Blending levels were 50%, and 100% (ASiR-V50, ASiR-V100, respectively).

RESULTS

For subjective assessments, images using ASiR-V100 were determined to have the best overall image quality, despite having received the worst score in the assessment of spatial resolution. For objective assessments, the image using ASiR-V50 and ASiR-V100 curves were slightly degraded in terms of low contrast z-MTF when compared to FBP.

CONCLUSION

ASiR-V was effective to improve the image quality when compared with FBP when reviewing sagittal reformats of the spine.

IMPLICATIONS FOR PRACTICE

This study suggests that high resolution is not the only thing that is key when reviewing sagittal CT spinal reformats. Such images should be provided as part of routine CT spine protocols, where available.

Clinical evaluation of a new adaptive iterative metal artifact reduction method in whole-body low-dose CT skeletal survey examinations

OBJECTIVE

To evaluate a new adaptive iterative metal artifact reduction algorithm (AiMAR) in whole-body low-dose CT (WBLDCT) skeletal survey examinations.

METHODS

Projection data were retrospectively obtained from 25 clinical WBLDCT skeletal survey patients, each with two types of metal implants. Images were reconstructed with bone and soft tissue kernels using four settings-original and AiMAR with strengths of 2, 4, and 5. All images were anonymized and randomized for a reader study, where three musculoskeletal radiologists independently determined the overall ranking of all series based on diagnostic quality, and local scoring of metal artifact and anatomy visualization for each implant. Quantitative image noise analysis was performed in areas close to the implants. Intraclass correlation coefficients (ICC) and Krippendorff's alpha were computed for inter-rater reliability.

RESULTS

AiMAR 4 was ranked the highest for 64.3% of the series across eight types of implants. For local scoring task, AiMAR 4 showed better metal artifact and anatomy visualization than the original and AiMAR 2. AiMAR 4 was comparable in anatomy visualization but inferior to AiMAR 5 in metal artifact scores. AiMAR 4 led to 56.3% noise reduction around the implant areas compared with the original images, and AiMAR 5 68.1% but also resulted in anatomy blurring in 40% of the implants. ICC and Krippendorff's alpha revealed at least substantial reliability in the local scores among the readers.

CONCLUSIONS

AiMAR was evaluated in WBLDCT skeletal surveys. AiMAR 4 demonstrated the highest overall quality ranking and improved local scores with noise reduction around implant areas.

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

For decades, the main imaging tool for multiple myeloma (MM) patient's management has been the conventional skeleton survey. In 2014 international myeloma working group defined the advantages of the whole-body low dose computed tomography (WBLDCT) as a gold standard, among imaging modalities, for bone disease assessment and subsequently implemented this technique in the MM diagnostic workflow. The aim of this study is to investigate, in a group of 30 patients with a new diagnosis of MM, the radiation dose (CT dose index, dose-length product, effective dose), the subjective image quality score and osseous/extra-osseous findings rate with a modified WBLDCT protocol. Spectral shaping and third-generation dual-source multidetector CT scanner was used for the assessment of osteolytic lesions due to MM, and the dose exposure was compared with the literature findings reported until 2020. Mean radiation dose parameters were reported as follows: CT dose index 0.3 ± 0.1 mGy, Dose-Length Product 52.0 ± 22.5 mGy*cm, effective dose 0.44 ± 0.19 mSv. Subjective image quality was good/excellent in all subjects. 11/30 patients showed osteolytic lesions, with a percentage of extra-osseous findings detected in 9/30 patients. Our data confirmed the advantages of WBLDCT in the diagnosis of patients with MM, reporting an effective dose for our protocol as the lowest among previous literature findings.

The Role of Low Dose Whole Body CT in the Detection of Progression of Patients with Smoldering Multiple Myeloma

Multiple myeloma (MM) is the second most common hematological malignancy, characterized by plasma cell bone marrow infiltration and end-organ involvement. Smoldering MM (SMM) is an intermediate clinical entity between MGUS and MM, with a risk of progression to symptomatic disease 10% per year. Bone disease is the most frequent symptom of MM, with ~90% of patients developing bone lesions throughout their disease course. Therefore, imaging plays a crucial role in diagnosis and management. Whole-body low-dose CT (WBLDCT) is widely available and has been incorporated in the latest diagnostic criteria of the IMWG. The purpose of this study was to evaluate the role of WBLDCT in the early identification of lesions in patients with SMM who progress solely with bone disease. In total, 100 asymptomatic patients were consecutively assessed with WBLDCT from July 2013 until March 2020 at baseline, 1-year after diagnosis and every 1 year thereafter. Ten percent of patients were identified as progressors with this single imaging modality. This is the first study to evaluate prospectively patients with SMM at different time points to identify early bone lesions related to MM evolution. Serial WBLDCT studies can identify early myeloma evolution and optimize disease monitoring and therapeutic strategies.

Multiple Myeloma: Role of Imaging in Diagnosis, Staging, and Treatment Response Assessment

Multiple myeloma is a common hematologic malignancy of plasma cells. Differentiating multiple myeloma from the precursor stages of monoclonal gammopathy of undetermined significance and smoldering multiple myeloma is very important because the treatment approach is different for each. The diagnosis is mainly clinical, while the role of imaging is confined to the staging process, assessing response to therapy, and monitoring for disease progression. In this article, we examine the role of different imaging modalities in patients with multiple myeloma.

Role of imaging in multiple myeloma

With rapid advancements in the diagnosis and treatment of multiple myeloma (MM), imaging has become instrumental in detection of intramedullary and extramedullary disease, providing prognostic information, and assessing therapeutic efficacy. Whole-body low dose computed tomography (WBLDCT) has emerged as the study of choice to detect osteolytic bone disease. Positron emission tomography/computed tomography (PET/CT) combines functional and morphologic information to identify MM disease activity and assess treatment response. Magnetic resonance imaging (MRI) has excellent soft-tissue contrast and is the modality of choice for bone marrow evaluation. This review focuses on the imaging modalities available for MM patient management, highlighting advantages, disadvantages, and applications of each.

Non-hematologic diagnosis of systemic mastocytosis: Collaboration of radiology and pathology

Systemic mastocytosis (SM) is a hematologic disease with a wide range of clinical courses ranging from an indolent condition with normal life expectancy to exceedingly aggressive disorder with a poor prognosis. The symptoms and signs of SM result from the release of mast cell mediators with heterogeneous functions, and/or organ damage from neoplastic mast cell infiltration, or both. Diagnostic criteria for SM are well-defined by the World Health Organization (WHO). However, the diagnosis of SM can be difficult when especially it is not in the differential diagnosis. Routinely used radiologic techniques (e.g., X-ray, ultrasound, CT scans can show findings such as lytic-, sclerotic- or mixed-bone lesions, splenomegaly, hepatomegaly, retroperitoneal or periportal mesenteric lymphadenopathy, and omental thickening). It is essential to emphasize that the constellation of these radiologic findings should strongly concern of SM, especially in patients who also have a skin rash, allergic reactions, gastrointestinal tract symptoms (lasting, intermittent nausea, diarrhea), paroxysmal tachycardias, unexplained weight loss, persistent bone pain, cytopenias, liver dysfunction, eosinophilia. These findings, even coincidentally noted, will likely lead to a tissue biopsy, which reveals diagnosis (as we discussed and illustrated some tissue biopsies here). Moreover, the role of MRI and new techniques such as [18-fluorodeoxyglucose positron emission computed tomography, fibroscan] in the diagnosis of SM have been discussed. Furthermore, we reviewed the use of radiologic methods to evaluate treatment response and prognostication of SM..

Tumor load in patients with multiple myeloma: β₂-microglobulin levels versus low-dose whole-body CT

OBJECTIVE

Beta-2-microglobulin is a serum marker of tumor burden in multiple myeloma (MM). Our aim was to correlate serum β₂-microglobulin levels in patients with MM to tumor burden determined by low-dose whole-body CT (LDWBCT).

MATERIALS AND METHODS

A total of 52 patients with newly diagnosed, untreated MM who underwent LDWBCT were included. LDWBCT scans were assessed by two musculoskeletal radiologists in consensus for focal lesions. The Durie and Salmon PLUS staging system was used for staging patients in stages I-III. β₂-microglobulin was also subdivided into stages I-III on the basis of the multiple myeloma International Staging System (ISS).

RESULTS

Using the Durie and Salmon PLUS staging system criteria for image evaluation, we were able to identify stage I MM in 17 patients, stage II MM in nine patients, and stage III MM in 26 patients. Eight of nine patients with stage II MM and 16 of 26 patients with stage III MM had normal β₂-microglobulin levels. Thus, 24 of 35 patients (68.6%) had 5 or more focal lesions and false-negative β₂-microglobulin levels.

CONCLUSION

Serum β₂-microglobulin levels alone may not indicate the full extent of tumor burden in a significant subset of myeloma patients.

Organ dose and total effective dose of whole-body CT in multiple myeloma patients

OBJECTIVE

To evaluate organ dose and total effective dose of whole-body low-dose CT (WBLDCT) performed on different CT-scanner models in patients with multiple myeloma (MM) and to compare it to the effective dose of radiographic skeletal survey and representative diagnostic CTs.

MATERIAL AND METHODS

We retrospectively analyzed data from 228 patients (47.4% females, mean age 67.9 ± 10.4 years, mean weight 81.8 ± 22.4 kg) who underwent WBLDCT for the work-up or surveillance of MM. Patients were scanned using one of six multi-detector CT-scanners. Organ doses and total effective doses per scan were calculated using a commercially available dose-management platform (Radimetrics, Bayer Healthcare, Leverkusen, Germany). The median effective dose was compared to radiographic skeletal survey and representative diagnostic CTs.

RESULTS

The mean effective dose of our WBLDCT-protocol was 4.82 mSv. A significantly higher effective dose was observed in females compared to males (4.95 vs. 4.70 mSv, P = 0.002). Mean organ dose ranged from 3.72 mSv (esophagus) to 13.09 mSv (skeleton). Mean effective dose varied amongst different CT-scanners (range 4.34-8.37 mSv). The median effective dose of WBLDCT was more than twice the dose of a skeletal survey (4.82 vs. 2.04 mSv), 23% higher than a diagnostic contrast-enhanced chest CT (3.9 mSv), 46% lower than a diagnostic contrast-enhanced abdomen/pelvis CT (9.0 mSv), and 45% lower than a lumbar spine CT (8.7 mSv).

CONCLUSIONS

WBLDCT in MM has a higher effective dose than a radiographic skeletal survey, but a lower effective dose than diagnostic CTs of lumbar spine, abdomen and pelvis. This underlines the broad applicability of WBLDCT in the management of MM patients.

Radiation dosimetry considerations for skeletal survey imaging of multiple myeloma

PURPOSE

This paper aims to review the dosimetry and utility of currently implemented imaging modalities for assessment of multiple myeloma and consider the role of tin filtration computed tomography (CT) as a potential replacement to current standard practice.

METHODS

Radiation output of tin CT was measured experimentally and used for software-based dose calculation. Resultant effective dose was then compared to calculated planar radiography doses and published doses of other imaging modalities.

RESULTS

Based on example patient parameters used for modalities and 14 projection planar radiography site protocols, doses are comparable between planar radiography and tin filtration CT (approximately 0.9 and 1.0 mSv respectively). Both studies carried a reduced radiation burden compared to Expected Pathologically Increased Contrast-CT (EPIC-CT), FDG-PET and MIBI SPECT/CT (5.7, 11.1-20.0 and 13.0 mSv respectively).

CONCLUSION

Tin filtered CT provided visualisation of multiple myeloma at doses comparable to planar radiography and where available may be a suitable alternative, following due consideration of patient specific justification and optimisation in line with best practice.

Value of low-dose whole-body CT in the management of patients with multiple myeloma and precursor states

OBJECTIVE

To determine the value of low-dose whole-body CT (WBCT) in the management of patients with multiple myeloma (MM) and precursor states.

MATERIALS AND METHODS

The study group comprised 116 patients (mean age: 68 ± 11 years, 48% women) who underwent WBCT for the work-up or surveillance of MM or MM precursor disease. WBCTs were reviewed for the presence of MM-related bone disease and incidental findings requiring therapy. The medical records, results from bone marrow aspirations and biopsies and follow-up imaging studies were reviewed to assess the influence of WBCT on patient management.

RESULTS

Whole-body CT led to a change in management in 32 patients (28%). Of those, 17 patients with MM precursor disease were found to have MM-related bone disease, 13 patients had progression of MM, requiring a change in treatment, in one patient hepatocellular carcinoma was diagnosed, requiring a change in therapy, and one patient had a rib lesion requiring intervention. In 65 patients (56%), WBCT was performed for surveillance of MM precursor disease or stable treated MM, and did not detect new lesions, thereby providing reassurance to the hematologist on disease status and management. In 15 patients (13%) WBCT was performed as a new baseline before a change or new therapy. In 4 patients (3%), WBCT was performed for a change in symptoms, but did not detect lesions that would lead to a change in management.

CONCLUSION

Whole-body CT provides important information for disease monitoring and detection of incidental findings, thereby improving the management of patients with MM.

Imaging in myeloma with focus on advanced imaging techniques

In recent years, there have been major advances in the imaging of myeloma with whole body MRI incorporating diffusion-weighted imaging, emerging as the most sensitive modality. Imaging is now a key component in the work-up of patients with a suspected diagnosis of myeloma. The International Myeloma Working Group now specifies that more than one focal lesion on MRI or lytic lesion on whole body low-dose CT or fludeoxyglucose (FDG) PET/CT fulfil the criteria for bone damage requiring therapy. The recent National Institute for Health and Care Excellence myeloma guidelines recommend imaging in all patients with suspected myeloma. In addition, there is emerging data supporting the use of functional imaging techniques (WB-DW MRI and FDG PET/CT) to predict outcome and evaluate response to therapy. This review summarises the imaging modalities used in myeloma, the latest guidelines relevant to imaging and future directions.

Managing the cervical spine in multiple myeloma patients

Discuss the relevant literature on surgical and nonsurgical treatments for multiple myeloma (MM) and their complementary effects on overall treatment. Existing surgical algorithms designed for neoplasia of the spine may not suit the management of spinal myeloma. Less than a fifth of metastatic, including myelomatous lesions, occur in the cervical spine but have a poorer prognosis and surgery in this area carries a higher morbidity. With the advances of chemotherapy, early access to radiotherapy, early orthosis management, and high definition imaging, including CT and MRI, surgical indications in MM have changed. Medical decompression (or oncolysis), including in the presence of neurological deficit and orthotic stabilization, are proving viable nonsurgical options to manage MM. A key to decision making is the assessment and monitoring of biomechanical spinal stability as part of a multidisciplinary approach.

Recommendations for acquisition, interpretation and reporting of whole body low dose CT in patients with multiple myeloma and other plasma cell disorders: a report of the IMWG Bone Working Group

Whole Body Low Dose CT (WBLDCT) has important advantages as a first-line imaging modality for bone disease assessment in patients with plasma cell disorders and has been included in the 2014 International Myeloma Working Group (IMWG) criteria for multiple myeloma (MM) definition. Nevertheless, standardization guidelines for the optimal use of WBLDCT in MM patients are still lacking, preventing its more widespread use, both in daily practice and clinical trials. The aim of this report by the Bone Group of the IMWG is to provide practical recommendations for the acquisition, interpretation and reporting of WBLDCT in patients with multiple myeloma and other plasma cell disorders.

MDCT in suspected lumbar spine fracture: comparison of standard and reduced dose settings using iterative reconstruction

AIM

To compare standard (SD-) and reduced-dose computed tomography (RD-CT) in combination with iterative reconstruction (IR) in emergency patients with suspected lumbar spine fracture.

MATERIAL AND METHODS

Forty emergency patients with suspected lumbar spinal disorder who underwent RD-CT and 40 body mass index-matched patients undergoing SD-CT were enrolled in this retrospective study. Raw data for RD-CT were reconstructed using two increasing IR levels (IRL) 4 and 6, while SD-CT was reconstructed with IRL3. Two radiologists assessed image quality, image noise, and reader confidence in interpreting findings of spinal fractures in a blinded manner.

RESULTS

Effective radiation dose was reduced by 50% using RD-CT. Overall subjective image quality (SIQ) was high for both protocols and slightly superior in the RD-CT protocol for both IRL compared to SD-CT. The detection rate of spinal disorders was high for both protocols with a high interobserver agreement.

CONCLUSION

RD-CT with higher levels of IR results in substantial dose reduction of 50% in lumbar spine CT while maintaining an excellent subjective image quality resulting in a high diagnostic confidence.

Diagnosis, treatment, and response assessment in solitary plasmacytoma: updated recommendations from a European Expert Panel

Solitary plasmacytoma is an infrequent form of plasma cell dyscrasia that presents as a single mass of monoclonal plasma cells, located either extramedullary or intraosseous. In some patients, a bone marrow aspiration can detect a low monoclonal plasma cell infiltration which indicates a high risk of early progression to an overt myeloma disease. Before treatment initiation, whole body positron emission tomography-computed tomography or magnetic resonance imaging should be performed to exclude the presence of additional malignant lesions. For decades, treatment has been based on high-dose radiation, but studies exploring the potential benefit of systemic therapies for high-risk patients are urgently needed. In this review, a panel of expert European hematologists updates the recommendations on the diagnosis and management of patients with solitary plasmacytoma.

Whole-body ultra-low dose CT using spectral shaping for detection of osteolytic lesion in multiple myeloma

OBJECTIVES

The aim of this study was to investigate the radiation dose and image quality of a whole-body low-dose CT (WBLDCT) using spectral shaping at 100 kV (Sn 100 kV) for the assessment of osteolytic lesions in patients with multiple myeloma.

METHODS

Thirty consecutive patients were retrospectively selected, who underwent a WBLDCT on a third-generation dual-source CT (DSCT) (Sn 100 kV, ref. mAs: 130). They were matched with patients, who were examined on a second-generation DSCT with a standard low-dose protocol (100 kV, ref. mAs: 111). Objective and subjective image quality, radiation exposure as well as the frequency of osteolytic lesions were evaluated.

RESULTS

All scans were of diagnostic image quality. Subjective overall image quality was significantly higher in the study group (p = 0.0003). Objective image analysis revealed that signal intensities, signal-to-noise ratio and contrast-to-noise ratio of the bony structures were equal or significantly higher in the control group. There was no significant difference in the frequency of osteolytic lesions (p = 0.259). The median effective dose of the study protocol was significantly lower (1.45 mSv vs. 5.65 mSv; p < 0.0001).

CONCLUSION

WBLDCT with Sn 100 kV can obtain sufficient image quality for the depiction of osteolytic lesions while reducing the radiation dose by approximately 74%.

KEY POINTS

• Spectral shaping using tin filtration is beneficial for whole-body low-dose CT • Sn 100 kV yields sufficient image quality for depiction of osteolytic lesions • Whole-body low-dose CT can be performed with a median dose of 1.5 mSv.

Automated Whole-Body Bone Lesion Detection for Multiple Myeloma on 68Ga-Pentixafor PET/CT Imaging Using Deep Learning Methods

The identification of bone lesions is crucial in the diagnostic assessment of multiple myeloma (MM). 68Ga-Pentixafor PET/CT can capture the abnormal molecular expression of CXCR-4 in addition to anatomical changes. However, whole-body detection of dozens of lesions on hybrid imaging is tedious and error prone. It is even more difficult to identify lesions with a large heterogeneity. This study employed deep learning methods to automatically combine characteristics of PET and CT for whole-body MM bone lesion detection in a 3D manner. Two convolutional neural networks (CNNs), V-Net and W-Net, were adopted to segment and detect the lesions. The feasibility of deep learning for lesion detection on 68Ga-Pentixafor PET/CT was first verified on digital phantoms generated using realistic PET simulation methods. Then the proposed methods were evaluated on real 68Ga-Pentixafor PET/CT scans of MM patients. The preliminary results showed that deep learning method can leverage multimodal information for spatial feature representation, and W-Net obtained the best result for segmentation and lesion detection. It also outperformed traditional machine learning methods such as random forest classifier (RF), k-Nearest Neighbors (k-NN), and support vector machine (SVM). The proof-of-concept study encourages further development of deep learning approach for MM lesion detection in population study.

The Critical Role of Imaging in the Management of Multiple Myeloma

Multiple myeloma (MM) is characterized by abnormal proliferation of plasma cells in the bone marrow leading to symptoms of anemia, renal failure, hypercalcemia, and bone lesions. Bone imaging is critical for the diagnosis, staging, assessment for the presence and extent of bone lesions, and initial treatment of MM. Skeletal survey is the preferred initial imaging modality due to its availability and low cost. However, it has poor sensitivity and patients with occult myeloma may escape detection, delaying their diagnosis and treatment. New cross-sectional imaging modalities such as low-dose whole body CT, MRI, and PET-CT have high sensitivity and specificity for detecting lytic lesions and extramedullary relapse in MM. The combined use of cross-sectional imaging may provide complimentary information for staging, prognosis, and disease monitoring. In this review, we will discuss commonly used imaging modalities and their advantages and disadvantages in the management of MM.

Effective dose in low-dose CT compared with radiography for templating of total hip arthroplasty

Background Recently, total hip arthroplasty (THA) has come to focus on restoration of individual anatomy including femoral neck anteversion and global offset (femoral and acetabular offset). Three-dimensional (3D) computed tomography (CT) data could provide a better basis for preoperative templating. The use of CT has been hampered by high radiation dose. Purpose To evaluate the effective dose used in pelvis and hip CT for THA templating. Material and Methods CT data from two clinical trials of THA were evaluated for CT scan length and volume CT dose index (CTDI_vol). The effective doses from hip-knee-ankle CT and pelvis and hip radiography were compared. Conversion factors for effective dose for radiography were calculated using the PCXMC software. Results A reduced dose CT protocol for pelvis imaging gave a substantial dose reduction compared with standard CT, while maintaining sufficient image quality. Between the two clinical trials there was a significant reduction in effective CT dose corresponding to changes in the CT protocol ( P < 0.01). The CT dose for the latter group was similar to, but nevertheless significantly higher than for, radiography ( P < 0.01). However, in the latter group the theoretical minimum dose for CT, using the minimum scan length required by the templating software, was equal to the dose from radiography. Conclusion Although the CT dose remained higher than for radiography, potential reductions in scan length could reduce the dose further so that CT would have a comparable level of risk to radiography with the added benefit of 3D templating.

Whole-body computed tomography versus conventional skeletal survey in patients with multiple myeloma: a study of the International Myeloma Working Group

For decades, conventional skeletal survey (CSS) has been the standard imaging technique for multiple myeloma (MM). However, recently whole-body computed tomography (WBCT) has been implemented into the diagnostic criteria of MM. This analysis compares sensitivity and prognostic significance of WBCT and CSS in patients with smoldering MM (SMM) and MM. Fifty-four of 212 patients (25.5%) had a negative CSS and a positive WBCT for osteolytic lesions (P<0.0001). Of 66 patients with SMM based on CSS, 12 (22.2%) had osteolytic lesions on WBCT. In comparison, WBCT failed to detect some bone destructions in the appendicular skeleton possibly due to limitations of the field of view. Presence of lytic bone lesions in WBCT was of borderline prognostic significance (P=0.051) for SMM patients, with a median time to progression of 38 versus 82 months for those without bone destructions. In conclusion, WBCT identifies significantly more sites of bone destruction than CSS. More than 20% of patients with SMM according to CSS have in fact active MM detectable with WBCT. On the basis of this and other studies, WBCT (either computed tomography (CT) alone or as part of a positron emission tomography-CT protocol) should be considered the current standard for the detection of osteolytic lesions in MM.

Diagnostic Advances in Multiple Myeloma

There have been several advances in the diagnosis of multiple myeloma (MM) in recent years. Serum free light chains have improved the ability to diagnose light chain MM; however, there are still difficulties in the serologic diagnosis of MM in some cases, particularly IgA MM. A novel heavy/light chain assay is able to improve the accuracy of diagnosis in these cases. Free light chains may also improve the diagnosis of extramedullary disease in difficult cases such as disease involving the central nervous system, pleura, or ascites. Advances in imaging such as whole body low-dose computed tomography (CT) whole body magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) have improved sensitivity in identifying lytic bone lesions, which would enable earlier treatment, and monitoring of osseous disease particularly in non- or oligosecretory disease. New techniques such as fused PET/MRI may further enhance the diagnosis of both bone lesions and extramedullary disease.

Guidelines for the use of imaging in the management of patients with myeloma

The role of imaging in myeloma has gained increasing importance over the past few years. The recently revised definition of myeloma from the International Myeloma Working Group (IMWG) includes cross sectional imaging as a method to define bone disease and also incorporates its use in the disease definition for patients with suspected smouldering myeloma. The National Institute for Health and Care Excellence myeloma guidelines also recommend cross sectional imaging for patients with suspected myeloma. There is also increasing use of imaging in disease assessments and the International Myeloma Working Group has recently incorporated imaging in defining new response categories of minimal residual disease negativity, with or without imaging-based evidence of disease. Plain X-rays have previously been the standard imaging modality included in a myeloma work up at presentation but evidence is mounting for use of cross-sectional modalities such as computed tomography (CT), magnetic resonance imaging (MRI) and 18 fluoro-deoxyglucose (18 F-FDG) positron emission tomography (PET)/CT. Funding and therefore availability of newer imaging techniques remains a barrier. Here, we propose an evidence-based approach to the use and technical application of the latest imaging modalities at diagnosis and in the follow-up of patients with myeloma and plasmacytoma.