Imaging of bone metastasis: An update

Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery

Simple Summary

Long bone metastases are frequently a pivotal point in the oncological history of patients. Weakening of the bone results in pathologic fractures that not only compromise patient function but also their survival. Therefore, the main issue for tumor boards remains timely assessment of the risk of fracture, as this is a key consideration in providing preventive surgery while also avoiding overtreatment. As the Mirels scoring system takes into account both the radiological and the clinical criteria, it has been used worldwide since the 1990s. However, due to increasing concern regarding the lack of accuracy, new thresholds have been defined for the identification of impending fractures that require prophylactic surgery, on the basis of axial cortical involvement and biomechanical models involving quantitative computed tomography. The aim of this review is to establish a state-of-the-art of the risk assessment of long bone metastases fractures, from simple radiologic scores to more complex multidimensional bone models, in order to define new decision-making tools.

Abstract

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

Automatic Diagnosis of Coronary Artery Disease in SPECT Myocardial Perfusion Imaging Employing Deep Learning

Focusing on coronary artery disease (CAD) patients, this research paper addresses the problem of automatic diagnosis of ischemia or infarction using single-photon emission computed tomography (SPECT) (Siemens Symbia S Series) myocardial perfusion imaging (MPI) scans and investigates the capabilities of deep learning and convolutional neural networks. Considering the wide applicability of deep learning in medical image classification, a robust CNN model whose architecture was previously determined in nuclear image analysis is introduced to recognize myocardial perfusion images by extracting the insightful features of an image and use them to classify it correctly. In addition, a deep learning classification approach using transfer learning is implemented to classify cardiovascular images as normal or abnormal (ischemia or infarction) from SPECT MPI scans. The present work is differentiated from other studies in nuclear cardiology as it utilizes SPECT MPI images. To address the two-class classification problem of CAD diagnosis, achieving adequate accuracy, simple, fast and efficient CNN architectures were built based on a CNN exploration process. They were then employed to identify the category of CAD diagnosis, presenting its generalization capabilities. The results revealed that the applied methods are sufficiently accurate and able to differentiate the infarction or ischemia from healthy patients (overall classification accuracy = 93.47% ± 2.81%, AUC score = 0.936). To strengthen the findings of this study, the proposed deep learning approaches were compared with other popular state-of-the-art CNN architectures for the specific dataset. The prediction results show the efficacy of new deep learning architecture applied for CAD diagnosis using SPECT MPI scans over the existing ones in nuclear medicine.

Correlation between ER, PR, HER-2, and Ki-67 with the risk of bone metastases detected by bone scintigraphy in breast cancer patients: A cross sectional study

BACKGROUND

Breast cancer is one of the most common cancers in women. About 30%-85% of breast cancers will metastasize to the bone during the course of the illness. Many studies have shown that molecular marker/subtypes can be useful in determining incidence of different and inconsistent bone metastases. This study aimed to determine the correlation of the risk of bone metastases in breast cancer based on the expression of molecular markers.

METHODS

The research was conducted retrospectively by searching patients' medical record data. The target population of this study was all patients diagnosed with breast cancer who came to our tertiary hospital in the Nuclear Medicine and Molecular Imaging Department from January 2012 to December 2016.

RESULTS

One hundred and thirty patients (n = 130) were enrolled during the study period with characteristics of sex, age, and immunohistochemical/molecular subtype examination that underwent bone scintigraphy. Mean of age was 50.2 (23-79) years. There were no significant correlations between ER, PR, and HER-2 expressions with bone metastases in breast cancer patients. Ki-67 was showed to be correlated with bone metastases in breast cancer patients in our bivariate analysis. Molecular subtype/markers had no statistically significant correlation with bone metastases in patients with breast cancer.

CONCLUSION

Ki-67 with high proliferation index was the most powerful molecular marker to determine the risk of bone metastases. The prevalence of bone metastases in the group with Ki-67 expression with high proliferation (≥20) was 1.8 times greater than the prevalence of bone metastases in the weakest HER-2 group.

Comparing 99mTc-PSMA to 99mTc-MDP in Prostate Cancer Staging of the Skeletal System

PURPOSE

This prospective study was aimed at assessing the ability of 99mTc-PSMA scan to detect bone metastases in prostate cancer (PCa) against 99mTc-MDP scan as a standard and assess the correlation of these modalities in PCa staging of bone involvement.

PATIENTS AND METHODS

Forty-one patients (41) with histologically confirmed PCa were scanned using both methods. Planar imaging was performed with additional regional SPECT/CT 3 to 4 hours posttracer injection. Scans were reported as positive, negative, or equivocal. In the case of positive scans, lesions were quantified by each of the 3 reporters separately. Planar and SPECT/CT images were reported together to obtain the final report on each scan.

RESULTS

Our preliminary results showed no significant difference in the detection of bone metastases between the 2 scans. 99mTc-PSMA detected 52 of the 55 bone lesions detected on 99mTc-MDP. However, 99mTc-PSMA provided extra information by reporting lymph nodal metastases in 7 patients and residual disease in the prostate in 2 patients with biochemical progression after radical therapy. In 1 patient, the PSMA scan resulted in change in management with patient now on 177Lu-PSMA radioligand therapy. Equivocal findings were reported in 4 patients on 99mTc-MDP and none on 99mTc-PSMA.

CONCLUSIONS

99mTc-PSMA was comparable to 99mTc-MDP in detection of bone metastases and demonstrated an additional benefit of providing information on visceral disease. 99mTc-PSMA may be a better alternative to 99mTc-MDP in staging, restaging, and assessment of patients with biochemical progression after radical therapy of PCa in a resource-limited setup like ours while also assisting to detect patients eligible for PSMA-labeled radioligand therapy.

Imaging and its Impact on Defining the Oligometastatic State

Successful treatment of oligometastatic disease (OMD) is facilitated through timely detection and localization of disease, both at the time of initial diagnosis (synchronous OMD) and following the initial therapy (metachronous OMD). Hence, imaging plays an indispensable role in management of patients with OMD. However, the challenges and complexities of OMD management are also reflected in the imaging of this entity. While innovations and advances in imaging technology have made a tremendous impact in disease detection and management, there remain substantial and unaddressed challenges for earlier and more accurate establishment of OMD state. This review will provide an overview of the available imaging modalities and their inherent strengths and weaknesses, with a focus on their role and potential in detection and evaluation of OMD in different organ systems. Furthermore, we will review the role of imaging in evaluation of OMD for malignancies of various primary organs, such as the lung, prostate, colon/rectum, breast, kidney, as well as neuroendocrine tumors and gynecologic malignancies. We aim to provide a practical overview about the utilization of imaging for clinicians who play a role in the care of those with, or at risk for OMD.

Staging Investigations in Asymptomatic Early Breast Cancer Patients at the Cancer Centre of Southeastern Ontario

Background: In 2012, the American Society for Clinical Oncology (ASCO) identified five key opportunities in oncology to improve patient care, recommending against imaging tests for the staging of patients with early breast cancer (EBC) at low risk for metastases. Similarly, the European Society of Medical Oncology (ESMO) guideline does not support radiological staging in asymptomatic EBC (aEBC). The purpose of this study was to assess local practice and outcomes of staging investigations (SIs) in aEBC at the Cancer Centre of Southeastern Ontario (CCSEO). Methods: A retrospective electronic and paper chart review was undertaken to identify all aEBC patients treated at our institution between January 2012 and December 2014. Patients with pathological staging of T1-T2 and N0-1 with any receptor status were included. We collected patient demographics, treatment and pathologic tumor characteristics. The use and outcomes of initial and follow-up SIs were recorded. Data were analyzed to determine associations between the use of SIs and clinical characteristics (chi-square tests, independent samples t-tests and Mann–Whitney U tests). Results: From 2012 to 2014, 295 asymptomatic EBC patients were identified. The mean age was 64, 81% were postmenopausal and 76% had breast conserving surgery. Stage distribution was as follows: stage I 42%, stage IIA 37% and stage IIB 21%. Receptor status was as follows: ER+ 84%, HER2+ 13% and triple negative 12%. Adjuvant chemotherapy was received by 36%, Trastuzumab by 10% and endocrine therapy by 76% of patients. Baseline SIs were performed in 168 patients (57%) for a total of 332 tests. Overt metastatic disease was found in five patients (one bone scan and four CT scans). Seventy-one out of the 168 patients (42%) who received initial staging imaging underwent 138 follow-up imaging tests, none of which were diagnostic for metastases. Nine patients with suspicious CT findings underwent biopsies, of which four were malignant (one metastatic breast cancer and three new primaries). Factors significantly associated with SI were as follows: younger age (p = 0.001), premenopausal status (p = 0.01), T2 stage (p < 0.001), N1 stage (p < 0.001), HER2 positive (p < 0.001), triple negative status (p = 0.007) and use of adjuvant chemotherapy (p < 0.001). Conclusions: Over a 3-year period at our institution, more than 50% of aEBC patients underwent a total of 470 initial and follow-up staging tests, yielding a cancer diagnosis (metastatic breast cancer or second primary cancer) in four patients. We, therefore, conclude that routine-staging investigations in aEBC patients have low diagnostic value, supporting current guidelines that recommend against the routine use of SI in this population.

Monitoring epidermal growth factor receptor C797S mutation in Japanese non-small cell lung cancer patients with serial cell-free DNA evaluation using digital droplet PCR

Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that is effective in treating both naïve and T790M-mutated EGFR-TKI-resistant non-small cell lung cancer patients. The EGFR C797S mutation is the major osimertinib resistance mechanism. The present study monitored the EGFR C797S mutation during osimertinib treatment in Japanese patients using droplet digital PCR (ddPCR). In our first cohort, C797S detection was validated with tumor specimens and/or plasma samples from 26 patients using ddPCR with custom-designed probes detecting and discriminating T790M and C797S in cis and trans positions. In our second cohort, 18 patients with EGFR-T790M who were going to start osimertinib were analyzed using ddPCR by collecting the plasma samples every month from the beginning of the course of osimertinib. In the first cohort, C797S was detected in 15.4% of patients. C797S and T790M in cis and trans positions were distinguished using ddPCR. In the second cohort, serial cfDNA evaluation revealed that the rate of EGFR mutation changes with disease state. Increases of EGFR mutation were detected, including C797S several months before the diagnosis of disease progression. As with the first cohort, C797S and T790M in cis and trans position were distinguished by ddPCR at disease progression. Coincidentally, in the first cohort, next generation sequencing detected NRAS Q61K mutation and the resistance with NRAS Q61K mutation was overcome by trametinib. In the second cohort, serial cfDNA analysis was useful for evaluating bone oligo-progression and local radiation therapy.

The prevalence of cancer in Britain before industrialization

BACKGROUND

To plan for cancer services in the future, the long view of cancer prevalence is essential. It might be suspected that cancer prevalence before tobacco and industrial revolution pollutants was quite different to today.

METHODS

To quantify the degree to which cancer prevalence may be changing over time, the authors analyzed 143 skeletons from 6 cemeteries from the Cambridge area (6th-16th centuries). Visual inspection coupled with screening using both plain radiographs and computed tomography scans was used to detect malignant lesions.

RESULTS

A total of 3.5% of individuals showed evidence for metastases. Factoring in modern data for the proportion of those with cancer that die with bone metastases, this suggests a minimum prevalence of all cancers at the time of death in medieval Britain to be approximately 9% to 14% of adults.

CONCLUSIONS

This figure compares with a 40% to 50% prevalence of cancer at the time of death for modern Britain. The difference may be explained by the effects of modern carcinogens, the spread of viruses that trigger malignancy, industrial pollutants, and longer life expectancy.

LAY SUMMARY

Until now, no one has been able to work out how common cancer was before the time people were exposed to tumor-inducing chemicals from tobacco and industrial factories. In this novel study, the authors have determined the percentage of people living in medieval Britain who had cancer metastases to bone at the time of their death and then compared that with modern data. It was found that cancer was approximately 25% as common in medieval times as it is today. This article suggests cancer was much more widespread in medieval times than was previously realized.

Effects of administration route on uptake kinetics of 18F-sodium fluoride positron emission tomography in mice

¹⁸F-sodium fluoride (¹⁸F-NaF) is a positron emission tomography (PET) radiotracer widely used in skeletal imaging and has also been proposed as a biomarker of active calcification in atherosclerosis. Like most PET radiotracers, ¹⁸F-NaF is typically administered intravenously. However in small animal research intravenous administrations can be challenging, because partial paravenous injection is common due to the small calibre of the superficial tail veins and repeat administrations via tail veins can lead to tissue injury therefore limiting the total number of longitudinal scanning points. In this paper, the feasibility of using intra-peritoneal route of injection of ⁸F-NaF to study calcification in mice was studied by looking at the kinetic and uptake profiles of normal soft tissues and bones versus intra-vascular injections. Dynamic PET was performed for 60 min on nineteen isoflurane-anesthetized male Swiss mice after femoral artery (n = 7), femoral vein (n = 6) or intraperitoneal (n = 6) injection of ⁸F-NaF. PET data were reconstructed and the standardised uptake value (SUV) and standardised uptake value ratio (SUVr) were estimated from the last three frames between 45- and 60-min and ⁸F-NaF uptake constant (K_i) was derived by Patlak graphical analysis. In soft tissue, the ¹⁸F-NaF perfusion phase changes depending on the type on injection route, whereas the uptake phase is similar regardless of the administration route. In bone tissue SUV, SUVr and K_i measures were not significantly different between the three administration routes. Comparison between PET and CT measures showed that bones that had the highest CT density displayed the lowest PET activity and conversely, bones where CT units were low had high ⁸F-NaF uptake. Intraperitoneal injection is a valid and practical alternative to the intra-vascular injections in small-animal ¹⁸F-NaF PET imaging providing equivalent pharmacokinetic data. CT outcome measures report on sites of stablished calcification whereas PET measures sites of higher complexity and active calcification.

A Prospective Study Comparing the Role of 18 FDG PET-CT with Contrast-Enhanced Computed Tomography and Tc99m Bone Scan for Staging Locally Advanced Breast Cancer

Locally advanced breast cancer (LABC) patients require an accurate staging of the disease to rule out distant metastases. Various imaging investigations are used to stage LABC patients. The present study is a prospective comparison of conventional imaging (CI) with fusion positron-emission tomography and computed tomography (PET-CT) scans in the staging of LABC patients. Seventy-three consecutive LABC patients presenting to the breast cancer clinic of the tertiary care cancer institute were included in the study. All patients underwent contrast-enhanced computed tomography, Tv99m bone scintigraphy, and fusion PET-CT. Histology of the metastatic site was confirmed wherever possible. The disparity between the two imaging findings was compared. Doubtful lesions were observed clinically for at least 2 years to confirm their nature. PET-CT detected a higher number of lymph nodes in the axilla, internal mammary, and supraclavicular region as compared to CI. PET-CT upstaged 36.98% and downstaged 5.4% of the patients respectively leading to a change in the management in 30.13% of the patients. Sensitivity, specificity, positive predictive value, and negative predictive value of CI and PET-CT were 71.87%, 87.80%, 82.14%, and 80%, and 90.90%, 90%, 88.23%, and 92.30% respectively. PET-CT was more accurate in staging the LABC patients as compared to CI. PET-CT is more accurate then contrast-enhanced CT and bone scintigraphy for staging locally advanced breast carcinoma patients. It can replace multiple organ-directed imaging in staging breast cancer. It can provide accurate staging of the disease so that patients can be prognosticated and can be directed to the most appropriate treatment plans.

Sodium Fluoride-18 and Radium-223 Dichloride Uptake Colocalize in Osteoblastic Mouse Xenograft Tumors

Background: Patients with osteoblastic bone metastases are candidates for radium-223 (²²³RaCl₂) therapy and may undergo sodium fluoride-18 (¹⁸F-NaF) positron emission tomography-computed tomography imaging to identify bone lesions. ¹⁸F-NaF has been shown to predict ²²³RaCl₂ uptake, but intratumor distributions of these two agents remain unclear. In this study, the authors evaluate the spatial distribution and relative uptakes of ¹⁸F-NaF and ²²³RaCl₂ in Hu09-H3 human osteosarcoma mouse xenograft tumors at macroscopic and microscopic levels to better quantify their correlation. Materials and Methods: ¹⁸F-NaF and ²²³RaCl₂ were co-injected into Hu09-H3 xenograft tumor severe combined immunodeficient mice. Tumor content was determined from in vivo biodistributions and visualized by PET, single photon emission computed tomography, and CT imaging. Intratumor distributions were visualized by quantitative autoradiography of tumor tissue sections and compared to histology of the same or adjacent sections. Results: ¹⁸F and ²²³Ra accumulated in proportional amounts in whole Hu09-H3 tumors (r² = 0.82) and in microcalcified regions within these tumors (r² = 0.87). Intratumor distributions of ¹⁸F and ²²³Ra were spatially congruent in these microcalcified regions. Conclusions: ¹⁸F-NaF and ²²³RaCl₂ uptake are strongly correlated in heterogeneously distributed microcalcified regions of Hu09-H3 xenograft tumors, and thus, tumor accumulation of ¹⁸F is predictive of ²²³Ra accumulation. Hu09-H3 xenograft tumors appear to possess certain histopathological features found in patients with metastatic bone disease and may be useful in clarifying the relationship between administered ²²³Ra dose and therapeutic effect.

The use of fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography as an effective method for staging in dogs with primary appendicular osteosarcoma

Fluorine-18-fluorodeoxyglucose (¹⁸ F-FDG) positron emission tomography/computed tomography (PET/CT) has been utilized in veterinary medicine to improve the detection and characterization of primary, recurrent, and secondary neoplasms; but its use as a staging tool for dogs diagnosed with appendicular osteosarcoma has not been published. The purpose of this retrospective, case series, descriptive study was to detail the use of ¹⁸ F-FDG PET/CT for staging a population of dogs with appendicular osteosarcoma, report the detection rate of secondary neoplastic lesions, and compare findings with published detection rates for other historically used imaging modalities. Seventy-one client-owned dogs with a confirmed diagnosis of appendicular osteosarcoma and staged with a whole-body ¹⁸ F-FDG PET/CT scan near the time of initial diagnosis were included. Each PET/CT study was re-evaluated for malignancy distinct from the primary disease entity based on a collective qualitative and quantitative assessment of ¹⁸ F-FDG uptake, CT appearance, and contrast enhancement characteristics. Following re-evaluation of each study, information pertaining to tissue sampling performed on identified lesions was retrieved from the medical record when available. Staging with ¹⁸ F-FDG PET/CT identified 17 of 71 (23.9%) and 12 of 71 (16.3%) dogs with a high suspicion or confirmation of a metastatic or comorbid malignant neoplasm respectively, with eight of 71 (11.3%) having both metastatic and comorbid lesions. The results of this study are suggestive that ¹⁸ F-FDG PET/CT is effective in identifying both osseous and soft tissue secondary neoplastic lesions in dogs afflicted with appendicular osteosarcoma, yielding an increased detection rate of all lesions compared those previously reported for skeletal scintigraphy or whole-body CT.

A retrospective study on the potential of 99m Tc-HDP imaging before therapy for individualizing treatments with 223 Ra-Cl2 for metastatic castration resistant prostate cancer

PURPOSE

Research on dose-effect correlation is necessary to move toward an individualization of treatments of metastatic castration resistant prostate cancer (mCRPC) with ²²³ Ra-Cl₂ . We first looked for a possible correlation of ^99m Tc-HDP lesion uptake in pretreatment whole-body scans (WBSs) with lesion absorbed dose. Moreover, we looked for a possible correlation of ^99m Tc-HDP lesion uptake in pretreatment WBSs and of lesion absorbed dose with relative change in the ^99m Tc-HDP lesion uptake obtained from pre- and post-treatment WBSs in patients treated for mCRPC with six cycles of ²²³ Ra-Cl₂ .

METHODS

Eleven patients received six cycles of 55 kBq/kg of ²²³ Ra-Cl₂ separated by 4 weeks. In addition, one patient received concomitant treatment with abiraterone and two patients with enzalutamide. The ^99m Tc-HDP WBSs were acquired before the first cycle and after the sixth cycle of the treatment. For the lesions with the higher ^99m Tc-HDP uptake, the absorbed dose was calculated for the first cycle. Lesion volume was determined from ^99m Tc-HDP SPECT/CT images before the first cycle and ²²³ Ra-Cl₂ activity in the lesions was determined from ²²³ Ra-Cl₂ planar images after the first cycle. The effect of the treatment was evaluated from the relative change of the mean and the maximum counts in the lesions, both estimated from the WBSs acquired before the first cycle and after the sixth cycle.

RESULTS

The absorbed dose was calculated for 30 lesions, with values ranging between 0.4 and 3.8 Gy (mean 1.5 Gy). A significant (P < 0.05) high positive linear correlation was found between the lesion absorbed dose in the first treatment cycle and the mean and maximum counts in the lesions in the WBSs acquired before the first cycle (R = 0.75 and 0.76, respectively). The relative change of the mean and the maximum counts in the lesions in the ^99m Tc-HDP WBSs showed a significant (P < 0.05) high positive logarithmic correlation with the ^99m Tc-HDP mean and maximum counts in the lesions before the first cycle (R = 0.79 and 0.78, respectively). Lastly, a significant (P < 0.05) high positive logarithmic correlation was also found between the relative change of the mean and the maximum counts in the lesions in the ^99m Tc-HDP WBSs and the lesion absorbed dose (R = 0.86 and 0.85, respectively). For this correlation the influence of the administered activity and of the concomitant treatments was not found to be significant (P > 0.05).

CONCLUSIONS

The high correlations found for the ^99m Tc-HDP lesion uptake before the first cycle lesion with the relative change in the ^99m Tc-HDP lesion uptake after the six cycles of ²²³ Ra-Cl₂ , and with the lesion absorbed dose in the first cycle show the potential of pretreatment ^99m Tc-HDP imaging in order to personalize the performance of these treatments.

Detection of bone metastases in uterine cancer: How common are they and should PET/CT be the standard for diagnosis?

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Osseous metastasis (OM) were found in 5% of endometrial cancers (EMCA), with predilection for type II histologies.

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Patients with serous EMCA had significantly higher odds of developing OM when compared to all other histologies.

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PET/CT appeared superior to conventional CT scans in diagnosing OM.

Objectives

Osseous metastases (OM) in endometrial cancer (EMCA) are thought to be rare. This study aimed to address the gap in present knowledge by defining the rate of OM in endometrial cancer (EMCA) as stratified by histology and ascertaining the best diagnostic modality for detection.

Methods

435 consecutive cases of EMCA evaluated in tertiary care setting were reviewed. Clinico-pathologic data were abstracted and analyzed.

Results

18/403 patients were found to have OM (4.6%). Majority were detected by PET/CT (13/18 (72%)), with conventional CT scans missing the diagnoses otherwise made by PET/CT scans in 2/9 patients. Patients with type II EMCA were at higher risk of developing OM compared with patients with type I EMCA; 2/234 patients with type I EMCA (0.85%) developed OM, as compared to 16/167 patients with type II EMCA (9.58%), OR = 12.3. Patients with serous histology had significantly higher odds of developing OM when compared to patients with non-serous histologies (OR 4, p = 0.001, 95% CI 1.54 to 10.76). Kaplan Myer survival function and log-rank analysis showed that the presence of OM was a significant negative prognosticator of survival, with median overall survival (mOS) of 16 months in OM patients vs. mOS undefined in non-OM patients (p < 0.0001).

Discussion

Incidence of detected OM was clinically significant, with most cases identified by PET/CT scans. Patients with type II EMCA, and in particular serous histology, were at a significantly higher risk of developing OM. OM when present, is an indicator of aggressive cancer biology and poor prognosis. Further studies are needed to ascertain the mechanism of predisposition to OM formation in serous EMCA and to confirm PET/CT as modality of choice for detection of OM.

Determination of the optimal cut-off value of serum prostate-specific antigen in the prediction of skeletal metastases on technetium-99m whole-body bone scan by receiver operating characteristic curve analysis

Radionuclide whole-body bone scan is a useful investigation of choice to detect the skeletal metastases in prostate cancer. It is indicated in patients having elevated serum prostate-specific antigen (Sr. PSA) or patients with bone pain. Elevated Sr. PSA levels have high predictive value for skeletal metastases; however, there is no consensus regarding cut-off value of Sr. PSA above which bone scan is indicated. This study was performed to find out the accuracy of Sr. PSA test and to know the optimal cut-off value of Sr. PSA with high sensitivity and specificity in the prediction of skeletal metastases on bone scan in prostate cancer patients. A retrospective analysis of medical records of 307 prostate cancer patients referred to the department of nuclear medicine for bone scan between June 2009 and June 2014 was done. Of 307 patients, 15 cases were excluded due to nonavailability of Sr. PSA. Bone scan was performed 3 h after administration of 20 mCi Tc-99m methylene diphosphonate intravenously. Whole-body sweep imaging was performed and spot views were taken wherever required. Of 292 cases, 174 (59.58%) patients had positive bone scan for metastases and 118 (40.41%) patients had negative bone scan for metastases. Maximum and minimum Sr. PSA levels in positive and negative bone scan patients were 1260 and 0.02 ng/ml and 198.34 ng/ml and 0.01 ng/ml, respectively. On comparison of the mean Sr. PSA levels between positive and negative groups, we found significant Sr. PSA levels (P < 0.05). We used receiver operating characteristic (ROC) curve analyses to find out the accuracy of Sr. PSA test and to know the optimal cut-off value of Sr. PSA with maximum sensitivity and specificity in the prediction of skeletal metastases on bone scan. Area under ROC curve was 0.878 (87%). This indicates that the accuracy of Sr. PSA test in the prediction of skeletal metastases on bone scan was good. The optimal cut-off value of Sr. PSA in the prediction of positive bone scan for skeletal metastases in the management of prostate cancer was 29.16 ng/ml, with sensitivity and specificity of 89.0% and 74.6%, respectively. In this study, we conclude that the accuracy of Sr. PSA test in the prediction of skeletal metastases is good. ROC-derived optimal cut-off value of Sr. PSA for positive skeletal metastases on bone scan is >29.16 ng/ml; thus, the chances of getting positive bone scan for skeletal metastasis are less in prostate cancer patients with Sr. PSA <29.16 ng/ml. ROC-derived sensitivity and specificity of different possible cut-off points of Sr. PSA help reduce the false positive results and increase the diagnostic accuracy of bone scan in the detection of skeletal metastases in prostate cancer patients.

Diagnostic accuracy of non-contrast abdominopelvic computed tomography scans in follow-up of breast cancer patients

OBJECTIVES

To evaluate the effectiveness of follow-up with non-enhanced CT (NECT) in patients with breast cancer.

METHODS

The present retrospective study included 1396 patients with breast cancer. Group A included patients with no metastasis to evaluate the diagnostic performance of NECT in detecting newly developed metastasis. Group B included patients with known hepatic metastasis to evaluate the accuracy of NECT for the assessment of hepatic metastasis.

RESULTS

Group A included 895 patients (mean age 52.8 years). Among them, 145 patients had 160 metastases. The per-patient sensitivities for diagnosing newly developed metastasis were 68.3 and 53.8% according to the two reviewers, while the per-lesion sensitivities were 89.4 and 85.0%. Sensitivities for bone metastasis were 98.9 and 95.9%, while sensitivities for hepatic metastasis were 73.7 and 68.4%. In group B, the accuracy of hepatic metastasis response evaluation according to the RECIST criteria was 70.8% for reviewer 1 and 63.8% for reviewer 2.

CONCLUSIONS

NECT showed inadequate diagnostic performance in detecting newly developed metastasis and in evaluating the response of hepatic metastasis. However, NECT can be utilized as a follow-up modality in patients with decreased renal function or hypersensitivity to iodinated contrast media.

ADVANCES IN KNOWLEDGE

The risk of side effects of contrast media should be considered as important when NECT can be utilized as a follow-up modality in decreased renal function patients.

In vivo selection of the MDA-MB-231br/eGFP cancer cell line to obtain a clinically relevant rat model for triple negative breast cancer brain metastasis

Young triple negative breast cancer (TNBC) patients are at high risk for developing very aggressive brain metastases associated with a poor prognosis and a high mortality rate. Preclinical models that allow follow-up by magnetic resonance imaging (MRI) can contribute to the development of new therapeutic approaches for brain metastasis. To date, preclinical brain tumor research has almost exclusively relied on xenograft mouse models. Yet, rats are an ideal model for imaging of brain metastasis as their larger brain offers better relative spatial resolution compared to a mouse brain. For the development of a clinically relevant rat model for TNBC brain metastasis, the MDA-MB-231br/eGFP cancer cell line can be used. However, as a result of species-dependent extracranial features, the propensity of the MDA-MB-231br/eGFP cancer cell line to metastasize exclusively to the brain needs to be enhanced by in vivo selection. In this study, repeated sequential passages of metastatic cancer cells obtained from brain metastases in nude rats were performed. Brain metastasis formation was evaluated using preclinical MRI, while bone metastasis formation was assessed using high-resolution computed tomography (CT) and 2-deoxy-2-[¹⁸F] fluoro-D-glucose ([¹⁸F] FDG) positron emission tomography (PET) imaging. Our results demonstrated that the metastatic tumor burden in the rat brain (number and volume) significantly increased with increasing passage, while the metastatic tumor burden in the skeleton (i.e., number of metastasis-affected bones) significantly decreased with increasing passage. However, bone metastasis development was not reduced to a negligible amount. Consequently, despite in vivo selection, our rat model is not recommended for investigating brain metastasis as a single disease. Our findings highlight the importance of well-reasoned selection of both the preclinical model and the cancer cell line in order to obtain reliable and reproducible scientific results.

Biomechanical Properties of Metastatically Involved Osteolytic Bone

PURPOSE OF REVIEW

Skeletal metastasis involves the uncoupling of physiologic bone remodeling resulting in abnormal bone turnover and radical changes in bony architecture, density, and quality. Bone strength assessment and fracture risk prediction are critical in clinical treatment decision-making. This review focuses on bone tissue and structural mechanisms altered by osteolytic metastasis and the resulting changes to its material and mechanical behavior.

RECENT FINDINGS

Both organic and mineral phases of bone tissue are altered by osteolytic metastatic disease, with diminished bone quality evident at multiple length-scales. The mechanical performance of bone with osteolytic lesions is influenced by a combination of tissue-level and structural changes. This review considers the effects of osteolytic metastasis on bone biomechanics demonstrating its negative impact at tissue and structural levels. Future studies need to assess the cumulative impact of cancer treatments on metastatically involved bone quality, and its utility in directing multimodal treatment planning.

Rare subtype of multiple myeloma presenting as sacroiliac joint pain in an avid golfer: a case report

OBJECTIVE

Kappa (κ) light chain multiple myeloma can be disguised as low back pain (LBP), and as such may present to a primary contact provider such as a chiropractor. The rarity and non-specific nature of the clinical presentation of this condition typically lead to a delayed diagnosis.

CASE PRESENTATION

A 53-year old male avid golfer presented to a chiropractor with a chief complaint of LBP. He was diagnosed with sacroiliac joint dysfunction. His pain was initially improving with chiropractic management. The character of his pain changed, and the chiropractor referred for further imaging. He was subsequently diagnosed with κ light chain multiple myeloma.

SUMMARY

This case presentation highlights that spinal malignancy is a possible cause of LBP. It reminds the clinician to investigate signs and symptoms that could lead to a suspicion of malignancy, to monitor patient progression, and consider further evaluations if the expected response to treatment is not achieved.

Multidisciplinary management of metastatic spine disease: initial symptom-directed management

In the past 2 decades, a deeper understanding of the cancer molecular signature has resulted in longer longevity of cancer patients, hence a greater population, who potentially can develop metastatic disease. Spine metastases (SM) occur in up to 70% of cancer patients. Familiarizing ourselves with the key aspects of initial symptom-directed management is important to provide SM patients with the best patient-specific options. We will review key components of initial symptoms assessment such as pain, neurological symptoms, and spine stability. Radiographic evaluation of SM and its role in management will be reviewed. Nonsurgical treatment options are also presented and discussed, including percutaneous procedures, radiation, radiosurgery, and spine stereotactic body radiotherapy. The efforts of a multidisciplinary team will continue to ensure the best patient care as the landscape of cancer is constantly changing.

French Multidisciplinary Approach for the Treatment of MSK Tumors

Several interventional treatments have recently been integrated into the therapeutic armamentarium available for the treatment of bone tumors. In some scenarios (e.g., osteoid osteoma), interventional treatments represent the sole and definitive applied treatment. Due to the absence of widely shared protocols and the complex multivariate scenarios underlying the clinical presentation of the remaining bone tumors including metastases, therapeutic strategies derived from a multidisciplinary tumor board are essential to provide effective treatments tailored to each patient. In the present review, we present the multidisciplinary therapeutic strategies commonly adopted for the most frequent bone tumors.

Guideline of guidelines: Muscle-invasive bladder cancer

Muscle-invasive bladder cancer accounts for 25% of bladder cancer cases and represents a spectrum of disease, which can result in significant morbidity and mortality for anyone affected. Current management has evolved through years of research and clinical practice. It is based on a risk-benefit approach, which is often tailored to the individual requirements of patients and involves cystectomy, neoadjuvant and adjuvant therapies, and multimodal surveillance paradigms to achieve high survival rates. Multiple guidelines exist to assist the clinicians in this decision-making process, but their adherence is often variable. In this article, we aimed to review the 4 most commonly used guidelines from the European Association of Urology, the National Institute for Health and Care Excellence, the National Comprehensive Cancer Network, and the American Urological Association.

Underutilisation of nuclear medicine scans at a regional hospital in Nigeria: need for implementation research

Background

Nuclear medicine needs better integration into the Nigerian health system. To understand the relevant public health initiatives that will be required, this study assessed the pattern of nuclear medicine imaging services at the first nuclear medicine centre in Nigeria from January 2010 to December 2018.

Methods

The data of consecutive nuclear medicine (NM) scans performed between 1st January 2010 and 31st December 2018 at the NM department in a tertiary hospital in Nigeria were extracted from patient records and analysed using SAS version 9.4 (SAS Institute, Cary, NC). The National Cancer Institute’s Joinpoint software and QCIS (QGIS project) were used to estimate imaging trends and geographical spread of patients.

Results

An average of 486 scans per year was performed during the study period. Patients travelled from 32 of Nigeria’s 36 states, and the majority (65%) travelled more than 100 km to obtain NM scans. Bone scans accounted for 88.1% of the studies. The remainder were renal scintigraphy (7.3%), thyroid scans (2.5%), whole-body iodine scans (1.7%) and others (0.4%).

Conclusions

NM in Nigeria appears underutilised. Furthermore, the studies to characterise the access gaps and implementation needs will contribute to the design of practical strategies to strengthen NM services in Nigeria.

Diagnosis and Treatment of Bone Metastases in Breast Cancer: Radiotherapy, Local Approach and Systemic Therapy in a Guide for Clinicians

The standard care for metastatic breast cancer (MBC) is systemic therapies with imbrication of focal treatment for symptoms. Recently, thanks to implementation of radiological and metabolic exams and development of new target therapies, oligometastatic and oligoprogressive settings are even more common-paving the way to a paradigm change of focal treatments role. In fact, according to immunophenotype, radiotherapy can be considered with radical intent in these settings of patients. The aim of this literature review is to analyze available clinical data on prognosis of bone metastases from breast cancer and benefits of available treatments for developing a practical guide for clinicians.

Spine and Non-spine Bone Metastases - Current Controversies and Future Direction

Bone is a common site of metastases in advanced cancers. The main symptom is pain, which increases morbidity and reduces quality of life. The treatment of bone metastases needs a multidisciplinary approach, with the main aim of relieving pain and improving quality of life. Apart from systemic anticancer therapy (hormonal therapy, chemotherapy or immunotherapy), there are several therapeutic options available to achieve palliation, including analgesics, surgery, local radiotherapy, bone-seeking radioisotopes and bone-modifying agents. Long-term use of non-steroidal analgesics and opiates is associated with significant side-effects, and tachyphylaxis. Radiotherapy is effective mainly in localised disease sites. Bone-targeting radionuclides are useful in patients with multiple metastatic lesions. Bone-modifying agents are beneficial in reducing skeletal-related events. This overview focuses on the role of surgery, including minimally invasive treatments, conventional radiotherapy in spinal and non-spinal bone metastases, bone-targeting radionuclides and bone-modifying agents in achieving palliation. We present the clinical data and their associated toxicity. Recent advances are also discussed.

Efficient Bone Metastasis Diagnosis in Bone Scintigraphy Using a Fast Convolutional Neural Network Architecture

(1) Background: Bone metastasis is among diseases that frequently appear in breast, lung and prostate cancer; the most popular imaging method of screening in metastasis is bone scintigraphy and presents very high sensitivity (95%). In the context of image recognition, this work investigates convolutional neural networks (CNNs), which are an efficient type of deep neural networks, to sort out the diagnosis problem of bone metastasis on prostate cancer patients; (2) Methods: As a deep learning model, CNN is able to extract the feature of an image and use this feature to classify images. It is widely applied in medical image classification. This study is devoted to developing a robust CNN model that efficiently and fast classifies bone scintigraphy images of patients suffering from prostate cancer, by determining whether or not they develop metastasis of prostate cancer. The retrospective study included 778 sequential male patients who underwent whole-body bone scans. A nuclear medicine physician classified all the cases into three categories: (a) benign, (b) malignant and (c) degenerative, which were used as gold standard; (3) Results: An efficient and fast CNN architecture was built, based on CNN exploration performance, using whole body scintigraphy images for bone metastasis diagnosis, achieving a high prediction accuracy. The results showed that the method is sufficiently precise when it comes to differentiate a bone metastasis case from other either degenerative changes or normal tissue cases (overall classification accuracy = 91.61% ± 2.46%). The accuracy of prostate patient cases identification regarding normal, malignant and degenerative changes was 91.3%, 94.7% and 88.6%, respectively. To strengthen the outcomes of this study the authors further compared the best performing CNN method to other popular CNN architectures for medical imaging, like ResNet50, VGG16, GoogleNet and MobileNet, as clearly reported in the literature; and (4) Conclusions: The remarkable outcome of this study is the ability of the method for an easier and more precise interpretation of whole-body images, with effects on the diagnosis accuracy and decision making on the treatment to be applied.

Inconclusive Bone Scan in Men with Intermediate and High-risk Prostate Cancer: What next?

OBJECTIVE

To evaluate the incidence of inconclusive bone scans and down-stream imaging and clinical follow-up generated, including subsequent treatment outcomes in men affected by inconclusive bone scans with intermediate- and high-risk prostate cancer.

DATA SOURCES

Retrospective study of clinical data for a Scottish population of men diagnosed with prostate cancer in the intermediate and high-risk groups.

CONCLUSION

Of the 1,246 patients included, initially 81 men were identified as having an inconclusive bone scan result following multidisciplinary team discussion. After further imaging, 24 patients remained inconclusive for metastasis. Of these, two patients received no treatment; one because of a watchful waiting decision, and one because of death. Of the 13 patients receiving radical treatment (laparoscopic radical prostatectomy or radiotherapy), three patients showed relapse (23%) indicating presence of microscopic disease and failure of radical treatment alone for these patients.

IMPLICATIONS FOR NURSING PRACTICE

This paper will assist nurses and multidisciplinary team members in understanding how patients diagnosed with intermediate- and high-risk prostate cancer with inconclusive bone scan results are subsequently imaged and managed in the current health care system. This raises awareness amongst nursing staff of disease recurrence and the possibility of downstream multimodality treatment for these men with inconclusive bone scans.

The Spectrum of Rib Neoplasms in Adults: A Practical Approach and Multimodal Imaging Review

OBJECTIVE. Adult neoplasms of the ribs are a heterogeneous group consisting of both benign and aggressive entities. Rib neoplasms have a variety of overlapping imaging features, with much of the imaging data disjointed across the musculoskeletal, thoracic, and oncologic imaging literature. Arrival at accurate diagnosis can therefore be quite challenging. This article consolidates this information and introduces the reader to an algorithmic approach to rib lesion evaluation based on imaging. CONCLUSION. Rib neoplasms are a diverse group of benign and malignant entities, which often makes determining an accurate diagnosis challenging. Evaluation requires a multipronged approach that incorporates radiographic imaging features, nonradiographic imaging findings, lesion location, and clinical data.

A Deep-Learning Approach for Diagnosis of Metastatic Breast Cancer in Bones from Whole-Body Scans

(1) Background: Bone metastasis is one of the most frequent diseases in breast, lung and prostate cancer; bone scintigraphy is the primary imaging method of screening that offers the highest sensitivity (95%) regarding metastases. To address the considerable problem of bone metastasis diagnosis, focused on breast cancer patients, artificial intelligence methods devoted to deep-learning algorithms for medical image analysis are investigated in this research work; (2) Methods: Deep learning is a powerful algorithm for automatic classification and diagnosis of medical images whereas its implementation is achieved by the use of convolutional neural networks (CNNs). The purpose of this study is to build a robust CNN model that will be able to classify images of whole-body scans in patients suffering from breast cancer, depending on whether or not they are infected by metastasis of breast cancer; (3) Results: A robust CNN architecture is selected based on CNN exploration performance for bone metastasis diagnosis using whole-body scan images, achieving a high classification accuracy of 92.50%. The best-performing CNN method is compared with other popular and well-known CNN architectures for medical imaging like ResNet50, VGG16, MobileNet, and DenseNet, reported in the literature, providing superior classification accuracy; and (4) Conclusions: Prediction results show the efficacy of the proposed deep learning approach in bone metastasis diagnosis for breast cancer patients in nuclear medicine.

Bone Metastasis: Current State of Play

Bone metastasis (BM) in cancer remains a critical issue because of its associated clinical and biological complications. Moreover, BM can alter the quality of life and survival rate of cancer patients. Growing evidence suggests that bones are a fertile ground for the development of metastasis through a "vicious circle" of bone resorption/formation and tumor growth. This review aims to outline the current major issues in the diagnosis and management of BM in the most common types of osteotropic cancers and describe the mechanisms and effects of BM. First, we discuss the incidence of BM through the following questions: Are we witnessing an increase in incidence, and are we now better equipped with modern imaging techniques? Is the advent of efficient bone resorption inhibitors affecting the bigger picture of BM management? Second, we discuss the potential effects of cancer progression and well-prescribed drugs, such as multitarget tyrosine kinase inhibitors, inhibitors of the mammalian target of rapamycin, and immune checkpoint inhibitors, on BM. Finally, we examine the duality of the effects of some therapies that may help in cancer treatment but may also contribute to further BM.

Imaging for Metastasis in Prostate Cancer: A Review of the Literature

Background: Initial staging and assessment of treatment activity in metastatic prostate cancer (PCa) patients is controversial. Indications for the various available imaging modalities are not well-established due to rapid advancements in imaging and treatment.

Methods: We conducted a critical literature review of the main imaging abnormalities that suggest a diagnosis of metastasis in localized and locally advanced PCa or in cases of biological relapse. We also assessed the role of the various imaging modalities available in routine clinical practice for the detection of metastases and response to treatment in metastatic PCa patients.

Results: In published clinical trials, the most commonly used imaging modalities for the detection and evaluation of therapeutic response are bone scan, abdominopelvic computed tomography (CT), and pelvic and bone magnetic resonance imaging (MRI). For the detection and follow-up of metastases during treatment, modern imaging techniques i.e., choline-positron emission tomography (PET), fluciclovine-PET, or Prostate-specific membrane antigen (PSMA)-PET provide better sensitivity and specificity. This is particularly the case of fluciclovine-PET and PSMA-PET in cases of biochemical recurrence with low values of prostate specific antigen.

Conclusions: In routine clinical practice, conventional imaging still have a role, and communication between imagers and clinicians should be encouraged. Present and future clinical trials should use modern imaging methods to clarify their usage.

[Evaluation of Post-reconstruction Filtering in Resolution Recovery Reconstruction for Bone SPECT Imaging]

PURPOSE

The aim of this study was to clarify the optimal post-reconstruction filtering type in the three- dimensional ordered subset expectation maximization (3D-OSEM) method for bone single photon emission computed tomography (SPECT) from image quality and quantitative values.

METHOD

We scanned a National Electrical Manufactures Association's body phantom for bone SPECT filled with radioactive solution of ^99mTc whose radioactivity concentration was accurately measured. The SPECT images were created using the 3D-OSEM method. Post-reconstruction filtering was performed using a Butterworth filter (BW), a Gaussian filter (GA), and a Hanning filter (HA) with various parameters. The image quality was evaluated by the normalized mean-squared error (NMSE) value and % of contrast-to-noise ratio (QNR₁₇). The image quality was evaluated by the error values between the measured radioactivity concentration and the true radioactivity concentration in the BG region and insert sphere.

RESULTS

The minimum NMSE values were 0.034 (BW), 0.036 (GA), and 0.035 (HA), and there was no difference depending on the filter type. The values of QNR₁₇ were 2.5 (BW), 2.6 (GA), and 2.6 (HA), and there was no difference depending on the filter type. The BG region was greatly affected by parameter changes in GA but less by those in BW and HA. The error values of the 37 mm insert sphere were 18.0% (BW), 28.2% (GA), and 26.2% (HA), and BW showed the lowest value.

CONCLUSION

Our results suggest that the post-reconstruction filtering type used in the 3D-OSEM method was BW from the image quality and quantitative values.

Role of Baseline and Post-Therapy 18F-FDG PET in the Prognostic Stratification of Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients Treated with Radium-223

Radium-223 dichloride (Ra223) represents the unique bone-directed treatment option that shows an improvement in overall survival (OS) in metastatic castrate resistant prostate cancer (mCRPC). However, there is an urgent need for the identification of reliable biomarkers to non-invasively determine its efficacy (possibly improving patients’ selection or identifying responders’ after therapy completion). 18F-Fluorodeoxyglucose (FDG)-avidity is low in naïve prostate cancer, but it is enhanced in advanced and chemotherapy-refractory mCRPC, providing prognostic insights. Moreover, this tool showed high potential for the evaluation of response in cancer patients with bone involvement. For these reasons, FDG Positron Emission Tomography (FDG-PET) might represent an effective tool that is able to provide prognostic stratification (improving patients selection) at baseline and assessing the treatment response to Ra223. We conducted a retrospective analysis of 28 mCRPC patients that were treated with Ra223 and submitted to bone scan and FDG-PET/CT for prognostic purposes at baseline and within two months after therapy completion. The following parameters were measured: number of bone lesions at bone scan, SUVmax of the hottest bone lesion, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). In patients who underwent post-therapy 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT), (20/28), PET Response Criteria in Solid Tumors (PERCIST), and European Organization for Research and Treatment of Cancer (EORTC) criteria were applied to evaluate the metabolic treatment response. The difference between end of therapy and baseline values was also calculated for Metabolic Tumor Volume (MTV), TLG, prostate-specific antigen (PSA), alkaline phosphatase (AP), and lactate dehydrogenase (LDH) (termed deltaMTV, deltaTLG, deltaPSA, deltaAP and deltaLDH, respectively). Predictive power of baseline and post-therapy PET- and biochemical-derived parameters on OS were assessed by Kaplan–Meier, univariate and multivariate analyses. At baseline, PSA, LDH, and MTV significantly predicted OS. However, MTV (but not PSA nor LDH) was able to identify a subgroup of patients with worse prognosis, even after adjusting for the number of lesions at bone scan (which, in turn, was not an independent predictor of OS). After therapy, PERCIST criteria were able to capture the response to Ra223 by demonstrating longer OS in patients with partial metabolic response. Moreover, the biochemical parameters were outperformed by PERCIST in the post-treatment setting, as their variation after therapy was not informative on long term OS. The present study supports the role of FDG-PET as a tool for patient’s selection and response assessment in mCRPC patients undergoing Ra223 administration.

Whole-body MRI: a powerful alternative to bone scan for bone marrow staging without radiation and gadolinium enhancer

PURPOSE

Whole-body magnetic resonance imaging (WB-MRI) is a radiation-free alternative to the ^99mTc-HDP bone scan (BS) for the detection of bone metastasis. The major drawback is the long examination time and application of gadolinium enhancer. The aim of this study is to analyze (i) the performance of WB-MRI versus the BS and (ii) the diagnostic benefit of gadolinium (WB-MRI + Gd) compared to a non-enhanced protocol (NE WB-MRI).

METHODS AND MATERIALS

1256 eligible WB-MRI scans were analyzed retrospectively with a single inclusion criterion, a clinical 12-month follow-up or a biopsy as ground truth. N = 285 patients received both a WB-MRI and a BS within 12 months. All the patients were imaged with a coronal T1w and a STIR, and n = 528 (42%) received an additional T1w-mDixon with gadoteridol (0.1 mmol Gd-DTPA/kg).

RESULTS

From 1256 eligible patients, n = 884 (70%) had breast cancer as a primary disease, n = 101(8%) prostate cancer, and n = 77(6%) lung cancer. The sensitivity (Se) and negative predictive value (NPV) of the WB-MRI was 98/99%, significantly higher compared to BS with 82/89%, P < 0.001 Mc Nemar's test. The specificity (Spe) and positive predictive value (PPV) of the WB-MRI and BS was 85/82% and 91/86%, respectively. The interobserver agreement between WB-MRI and BS was 71%, Cohen's kappa 0.42. Analysis of the added diagnostic value of gadolinium revealed Se/Spe/PPV/NPV of 98/93/92/98% for the NE WB-MRI and 99/93/85/100% for the WM-MRI + Gd, P > 0.05 binary logistic regression with Fischer's exact test.

CONCLUSION

WB-MRI exceeds the sensitivity of BS without compromising the specificity, even after omitting the gadolinium enhancer.

Medical infrared thermal imaging of canine appendicular bone neoplasia

Background

Medical infrared thermal imaging (MITI) is a noninvasive imaging modality used in veterinary medicine as a screening tool for musculoskeletal and neurological disease processes. An infrared camera measures the surface body heat and produces a color map that represents the heat distribution. Local trauma or disease can impair the autonomic nervous system, which leads to changes in the local dermal microcirculation and subsequent alteration of surface body heat. Disruption of autonomic flow to the cutaneous vasculature at deeper levels can also result in asymmetric thermographic results. The purpose of this study was to evaluate surface temperature differences between limbs affected by bone neoplasia and their normal contralateral limbs.

Results

A statistically significant difference in average temperature was noted between regions of interest of the two groups (paired difference: 0.53 C° ± 0.14; P = 0.0005). In addition, pattern recognition analysis yielded a 75–100% success rate in lesion identification.

Conclusions

Significant alterations noted with average temperature and thermographic patterns indicate that MITI can document discernible changes associated with the presence of canine appendicular bone tumors. While MITI cannot be used as the sole diagnostic tool for bone cancer, it can be used as a screening modality and may be applicable in early detection of cancer.

The Dixon technique for MRI of the bone marrow

Dixon sequences are established as a reliable MRI technique that can be used for problem-solving in the assessment of bone marrow lesions. Unlike other fat suppression methods, Dixon techniques rely on the difference in resonance frequency between fat and water and in a single acquisition, fat only, water only, in-phase and out-of-phase images are acquired. This gives Dixon techniques the unique ability to quantify the amount of fat within a bone lesion, allowing discrimination between marrow-infiltrating and non-marrow-infiltrating lesions such as focal nodular marrow hyperplasia. Dixon can be used with gradient echo and spin echo techniques, both two-dimensional and three-dimensional imaging. Another advantage is its rapid acquisition time, especially when using traditional two-point Dixon gradient echo sequences. Overall, Dixon is a robust fat suppression method that can also be used with intravenous contrast agents. After reviewing the available literature, we would like to advocate the implementation of additional Dixon sequences as a problem-solving tool during the assessment of bone marrow pathology.

Hyperpolarized 13C-pyruvate MRI detects real-time metabolic flux in prostate cancer metastases to bone and liver: a clinical feasibility study

Background

Hyperpolarized (HP) ¹³C-pyruvate MRI is a stable-isotope molecular imaging modality that provides real-time assessment of the rate of metabolism through glycolytic pathways in human prostate cancer. Heretofore this imaging modality has been successfully utilized in prostate cancer only in localized disease. This pilot clinical study investigated the feasibility and imaging performance of HP ¹³C-pyruvate MR metabolic imaging in prostate cancer patients with metastases to the bone and/or viscera.

Methods

Six patients who had metastatic castration-resistant prostate cancer were recruited. Carbon-13 MR examination were conducted on a clinical 3T MRI following injection of 250 mM hyperpolarized ¹³C-pyruvate, where pyruvate-to-lactate conversion rate (k_PL) was calculated. Paired metastatic tumor biopsy was performed with histopathological and RNA-seq analyses.

Results

We observed a high rate of glycolytic metabolism in prostate cancer metastases, with a mean k_PL value of 0.020 ± 0.006 (s⁻¹) and 0.026 ± 0.000 (s⁻¹) in bone (N = 4) and liver (N = 2) metastases, respectively. Overall, high k_PL showed concordance with biopsy-confirmed high-grade prostate cancer including neuroendocrine differentiation in one case. Interval decrease of k_PL from 0.026 at baseline to 0.015 (s⁻¹) was observed in a liver metastasis 2 months after the initiation of taxane plus platinum chemotherapy. RNA-seq found higher levels of the lactate dehydrogenase isoform A (Ldha,15.7 ± 0.7) expression relative to the dominant isoform of pyruvate dehydrogenase (Pdha1, 12.8 ± 0.9).

Conclusions

HP ¹³C-pyruvate MRI can detect real-time glycolytic metabolism within prostate cancer metastases, and can measure changes in quantitative k_PL values following treatment response at early time points. This first feasibility study supports future clinical studies of HP ¹³C-pyruvate MRI in the setting of advanced prostate cancer.

Case of atypical femoral fractures that mimicked the typical imaging findings of prostate cancer-induced bone metastasis

INTRODUCTION

Atypical femoral fractures are atraumatic or minimally traumatic fractures and rare side effects of bone resorption inhibitors. Bone resorption inhibitors are frequently used in the treatment of prostate cancer.

CASE PRESENTATION

A 62-year-old man complained of difficulty in walking and left lower limb pain. Androgen deprivation and denosumab therapy for prostate cancer-induced bone metastasis was initiated 27 months ago. Even though the prostate-specific antigen level did not increase, imaging studies indicated the possibility of bone metastasis. The patient underwent bone biopsy; however, no malignancy was detected. Afterward, he had a fall, causing a complete fracture in his left femur.

CONCLUSION

Atypical femoral fractures occasionally mimic typical imaging findings and outcomes of bone metastasis. This case is important for recognizing such cases.

Protocol-driven multidetector SPECT/CT: integration of hybrid imaging into the routine workflow of whole-body bone scintigraphy in oncology patients

AIM

To analyse the additional clinical value of protocol-driven and selective use of multidetector single-photon-emission tomography/computed tomography (SPECT/CT) in oncology patients undergoing whole-body bone scintigraphy (BS) and to analyse reporter confidence in diagnosis with and without SPECT/CT.

MATERIALS AND METHODS

During a 2-year period, 2,954 whole-body BS examinations were performed in oncology patients, with 444 (15%) undergoing additional protocol-driven SPECT/CT. Retrospective evaluation of planar BS and SPECT/CT images was performed by two experienced dual-trained nuclear medicine radiologists. The BS and SPECT/CT images were graded blindly using a five-point scale designed to evaluate the likelihood of a lesion being benign or malignant. Interpretation was applied on a per-patient basis.

RESULTS

There was a 74.5% increase in definitive diagnostic classification and a 26.6% reduction in equivocal findings with SPECT/CT when compared to BS alone (p<0001). Of cases initially classified as "probably benign" on BS, 5.1% (10/193) were reclassified to "probably malignant" (1%) or "malignant" (4.1%) using the SPECT/CT data. The highest impact in reporter confidence was seen with SPECT/CT in the interpretation of lesions within the pelvis (34%), ribs (23%), lumbar spine (22%), and thoracic spine (21%).

CONCLUSION

Protocol-driven, selective use of SPECT/CT imaging to augment planar BS reduces equivocal findings and improves reporter confidence whilst minimising the impact on patient and reporting workflows.

Histopathological Spectrum of Bone Changes in Skeletal Metastasis

Background: Metastatic carcinoma is the most common secondary malignant tumor affecting the bone. Bone is the third most common site for metastasis after lung and liver. The present study was planned to analyze the histomorphological patterns of bone changes in metastatic tumors and their correlation with the radiological findings. Materials and Methods: The current prospective study was conducted over a span of 2 years, encompassing 150 patients with clinically and radiologically suspected metastatic bone disease. Bone biopsy samples were studied for the pattern of bone changes. Results: Of 150 total cases, 30 cases had metastatic bone tumors. The age of the patients ranged from 37 to 84 years (mean: 57.57 ± 11.9 years). Male-to-female ratio was 2:1. All patients with metastasis presented with a complaint of pain followed by tenderness (20, 66.7%). The lesions were commonly located in the vertebral column (14, 46.7%), followed by femur (6, 20%). The primary site was known in 21 (70%) cases. The tumor histotypes were adenocarcinoma (23, 76.7%), squamous cell carcinoma (5, 16.7%), pleomorphic sarcoma (1, 3.3%), and malignant melanoma (1, 3.3%). Histomorphological patterns of bone changes were osteolytic (16, 53.3%), mixed (8, 26.7%), and osteoblastic (6, 20.0%). Correlation between the radiological findings and histopathological patterns of metastases was found to be statistically significant. Conclusions: Histomorphological assessment of bone changes in metastasis is an important parameter. Besides the histological categorization of metastatic bone disease, it plays a pivotal role in identification of the primary tumor site.

Treatment Response Assessment of Skeletal Metastases in Prostate Cancer with 18F-NaF PET/CT

PURPOSE

To determine the utility of 18F-sodium fluoride positron emission tomography-computed tomography (18F-NaF PET/CT) in the imaging assessment of therapy response in men with osseous-only metastatic prostate cancer.

METHODS

In this Institutional Review Board-approved single institution retrospective investigation, we evaluated 21 18F-NaF PET/CT scans performed in 14 patients with osseous metastatic disease from prostate cancer and no evidence of locally recurrent or soft-tissue metastatic disease who received chemohormonal therapy. Imaging-based qualitative and semi-quantitative parameters were defined and compared with changes in serum PSA level.

RESULTS

Qualitative and semi-quantitative image-based assessments demonstrated > 80% concordance with good correlation (SUVmax κ = 0.71, SUVavg κ = 0.62, SUVsum κ = 0.62). Moderate correlation (κ = 0.43) was found between SUVmax and PSA-based treatment response assessments. There was no statistically significant correlation between PSA-based disease progression and semi-quantitative parameters. Qualitative imaging assessment was moderately correlated (κ = 0.52) with PSA in distinguishing responders and non-responders.

CONCLUSION

18F-NaF PET/CT is complementary to biochemical monitoring in patients with bone-only metastases from prostate cancer which can be helpful in subsequent treatment management decisions.