Brain metastatic volume and white matter lesions in advanced cancer patients

Hemodynamic imaging parameters in brain metastases patients - Agreement between multi-delay ASL and hypercapnic BOLD

Arterial spin labeling (ASL) MRI is a routine clinical imaging technique that provides quantitative cerebral blood flow (CBF) information. A related technique is blood oxygenation level-dependent (BOLD) MRI during hypercapnia, which can assess cerebrovascular reactivity (CVR). ASL is weighted towards arteries, whereas BOLD is weighted towards veins. Their associated parameters in heterogeneous tissue types or under different hemodynamic conditions remains unclear. Baseline multi-delay ASL MRI and BOLD MRI during hypercapnia were performed in fourteen patients with brain metastases. In the ROI analysis, the CBF and CVR values were positively correlated in regions showing sufficient reserve capacity (i.e. non-steal regions, rrm = 0.792). Additionally, longer hemodynamic lag times were related to lower baseline CBF (rrm = -0.822) and longer arterial arrival time (AAT; rrm = 0.712). In contrast, in regions exhibiting vascular steal an inverse relationship was found with higher baseline CBF related to more negative CVR (rrm = -0.273). These associations were confirmed in voxelwise analyses. The relationship between CBF, AAT and CVR measures seems to be dependent on the vascular status of the underlying tissue. Healthy tissue relationships do not hold in tissues experiencing impaired or exhausted autoregulation. CVR metrics can possibly identify at-risk areas before perfusion deficiencies become visible on ASL MRI, specifically within vascular steal regions.

Artificial Intelligence to Reduce or Eliminate the Need for Gadolinium-Based Contrast Agents in Brain and Cardiac MRI: A Literature Review

ABSTRACT

Brain and cardiac MRIs are fundamental noninvasive imaging tools, which can provide important clinical information and can be performed without or with gadolinium-based contrast agents (GBCAs), depending on the clinical indication. It is currently a topic of debate whether it would be feasible to extract information such as standard gadolinium-enhanced MRI while injecting either less or no GBCAs. Artificial intelligence (AI) is a great source of innovation in medical imaging and has been explored as a method to synthesize virtual contrast MR images, potentially yielding similar diagnostic performance without the need to administer GBCAs. If possible, there would be significant benefits, including reduction of costs, acquisition time, and environmental impact with respect to conventional contrast-enhanced MRI examinations. Given its promise, we believe additional research is needed to increase the evidence to make these AI solutions feasible, reliable, and robust enough to be integrated into the clinical framework. Here, we review recent AI studies aimed at reducing or replacing gadolinium in brain and cardiac imaging while maintaining diagnostic image quality.

Evaluating Physiological MRI Parameters in Patients with Brain Metastases Undergoing Stereotactic Radiosurgery-A Preliminary Analysis and Case Report

Brain metastases occur in ten to thirty percent of the adult cancer population. Treatment consists of different (palliative) options, including stereotactic radiosurgery (SRS). Sensitive MRI biomarkers are needed to better understand radiotherapy-related effects on cerebral physiology and the subsequent effects on neurocognitive functioning. In the current study, we used physiological imaging techniques to assess cerebral blood flow (CBF), oxygen extraction fraction (OEF), cerebral metabolic rate of oxygen (CMRO2) and cerebrovascular reactivity (CVR) before and three months after SRS in nine patients with brain metastases. The results showed improvement in OEF, CBF and CMRO2 within brain tissue that recovered from edema (all p ≤ 0.04), while CVR remained impacted. We observed a global post-radiotherapy increase in CBF in healthy-appearing brain tissue (p = 0.02). A repeated measures correlation analysis showed larger reductions within regions exposed to higher radiotherapy doses in CBF (rrm = -0.286, p < 0.001), CMRO2 (rrm = -0.254, p < 0.001), and CVR (rrm = -0.346, p < 0.001), but not in OEF (rrm = -0.004, p = 0.954). Case analyses illustrated the impact of brain metastases progression on the post-radiotherapy changes in both physiological MRI measures and cognitive performance. Our preliminary findings suggest no radiotherapy effects on physiological parameters occurred in healthy-appearing brain tissue within 3-months post-radiotherapy. Nevertheless, as radiotherapy can have late side effects, larger patient samples allowing meaningful grouping of patients and longer follow-ups are needed.

Computed tomography density changes of bone metastases after concomitant denosumab

OBJECTIVE

To evaluate bone density changes at the level of normal trabecular bone and bone metastases (BMs) after denosumab (DM) treatment in oncologic patients.

MATERIALS AND METHODS

We retrospectively evaluated 31 consecutive adult patients with histologically confirmed solid tumors with at least one newly diagnosed bone metastatic lesion detected at CT. Patients received treatment with DM, 120 mg subcutaneous every 28 days for at least 6 months. Bone density was determined at the level of BMs and at the level of normal trabecular bone of lumbar vertebrae using a region of interest (ROI)-based approach.

RESULTS

A progressive increase in CT bone density was demonstrated at the level of normal trabecular bone at 6 months (18% ± 5%) and 12 months (23% ± 7%) after the treatment begins. BMs showed a significant increase in CT bone density (p < 0.05) as compared to baseline after 6 months (57% ± 15%) and 12 months (1.06 ± 0.25 times higher) after treatment.

CONCLUSION

We have found that long-term treatment with DM increases bone density progressively in oncologic patients. This effect can be observed not only at the level of secondary lesions but also at the level of apparently normal trabecular bone and is more pronounced for osteolytic metastases.

Predictive Indicators of Brain Metastasis-Free Survival in Patients With Lung Cancer at a Chinese Cancer Center

Introduction

Metastasis tumors of the brain derive mostly from lung cancer, breast cancer, melanoma, and more commonly among lung cancer patients. Once brain metastasis is diagnosed, the prognosis of untreated patients is shown to be very poor. In this study, we describe the clinical and pathological features of patients with lung cancer at our institution from 2009 to 2021. We also examined factors like gender, type, size, and location of the primary tumor and leukoaraiosis level at the first visit are associated with patients’ brain metastasis-free survival (the time free of brain metastases since the first diagnosis of lung cancer).

Materials and methods

We retrospectively reviewed patients with a final histologic diagnosis of lung cancer from September 2009 to January 2015. The evaluation included history, physical examination, and contrast-enhanced computerized tomography of the chest. Contrast-enhanced magnetic resonance imaging of the head was performed at the first visit and following treatment. The patients’ age, gender, tumor size, histology type, location of the lung tumor, and leukoaraiosis level at the first visit were recorded and correlated to the patients’ brain-metastasis-free survival time.

Results

The study included 68 patients - 39 males and 29 females -with a mean age of 55.15 years (range 35-69 years). Adenocarcinoma was diagnosed in 47 patients (22 males and 25 females), Squamous carcinoma was diagnosed in 12 patients (9 males and 3 females), non-small cell lung carcinoma was diagnosed in 3 patients (2 males and one female), one male patient had the diagnosis of adenosquamous tumor and 1 male patient had the diagnosis of neuroendocrine tumor. Tumor size was <3 cm in 19 patients, 3-5 cm in 29 patients, 5-10 cm in 17 patients, and three other patients’ size was hard to measure. Of the 68 patients, 10 patients were detected as brain metastasis by magnetic resonance imaging at first diagnosis, 22 patients were diagnosed as brain metastasis during the follow-up visits, 36 patients were not found as brain metastasis until the last visit. According to the Cox regression univariate analysis, two factors were correlated to shorter brain metastasis-free survival: Not-squamous lung carcinoma (SCC) and higher location of the tumor. The multivariate statistical analysis correlated two factors to shorter brain metastasis-free survival: non-SCC histology type and age≥62.

Conclusions

In conclusion, we found that SCC had a lower incidence of brain metastasis in patients than other lung cancer types. According to the Cox regression multivariate analysis, age <62 and SCC were two protective factors of brain metastasis. According to the Cox regression univariate and analysis. The lower location of the tumor was the protective factor of brain metastasis. According to the Cox regression univariate analysis, other parameters, such as gender or tumor size, did not have a role in brain metastasis-free survival in these patients.

Mapping distribution of brain metastases: does the primary tumor matter?

Purpose

Prior reports on the location and sizes of brain metastases almost entirely focus on patients with primary breast and pulmonary cancer. This is the first study comparing multiple other types of cancer that metastasize to the brain.

Methods

This monocentric retrospective study includes 369 untreated patients with 3313 intraaxial brain metastases. Following semi-manual segmentation of metastases on post-contrast T1WI, cumulative spatial probability distribution maps of brain metastases were created for the whole group and for all primary tumors. Furthermore, mixed effects logistic regression model analysis was performed to determine if the primary tumor, patient age, and patient sex influence lesion location.

Results

The cerebellum as location of brain metastases was proportionally overrepresented. Breast and pulmonary cancer caused higher number of brain metastases to what would normally be expected. Multivariate analyses revealed a significant accumulation of brain metastases from skin cancer in a frontal and from breast and gastrointestinal cancer in a cerebellar location.

Conclusion

Distribution of brain metastases is very heterogeneous for the distinct primaries, possibly reflecting the diversity of mechanisms involved in brain metastases formation. In daily clinical practice distribution patters may be beneficial to predict the primary cancer site, if unknown.

Electronic supplementary material

The online version of this article (10.1007/s11060-020-03419-6) contains supplementary material, which is available to authorized users.

Inverse Perfusion Requirements of Supra- and Infratentorial Brain Metastases Formation

Background and Aims: Vascular border zones and the gray-white matter junction are preferred sites for the development of brain metastases (BM), whereas microvascular lesions are known to be a protective factor. In this proof of concept study, we aim to study the relationship of blood perfusion and the spatial distribution of BM.

Materials and Methods: An average CT perfusion atlas of 107 healthy patients was created. Voxel-wise reference perfusion values were extracted from BM-negative and BM-positive regions in a second cohort of 100 untreated patients harboring 809 BM confirmed by MRI. A comparison of regional perfusion values was performed using the independent t-test.

Results: In contrast to supratentorial BM that develop preferably in areas with lower CBV/CBF and longer MTT/TTP compared to the average regional perfusion (p < 0.001), infratentorial BM showed a higher CBV/CBF and shorter MTT/TTP (p < 0.001).

Conclusion: Our results imply differing pathophysiological mechanisms underlying supra- and infratentorial BM spreading. The inverse perfusion patterns may result from differences in vascular supply, hemodynamic requirements, and/or production of pro-angiogenic factors.

Negative impact of leukoaraiosis on the incidence of brain metastases in patients with lung cancer

The embolization of cancer cells to cerebral vessels occurs early in the multi-step metastatic process. We aimed to determine whether the presence of leukoaraiosis (LA) before treatment would predict the development of brain metastases (BM) in patients with lung cancer. Between January 2014 and June 2015, 1007 patients underwent initial (i.e., prior to any chemotherapy) or routine magnetic resonance (MR) imaging of the brain and exhibited no evidence of BM. Of these, 189 underwent repeat MR imaging; 34 of 189 patients (18%) developed new BM, whereas 155 patients did not. LA was retrospectively evaluated according to Fazekas scale on the initial screening MR images of these 189 patients. The frequency of grade 0 periventricular hyperintensity (PVH) was greater among patients with BM, compared to those without BM (p = 0.001). In a multivariate analysis, patients with adenocarcinoma (95% confidence interval [CI] 1.8–171.8) and small cell carcinoma (95% CI 1.4–172.4) respectively developed BM at 9.3- and 8.8-fold higher rates than those with squamous cell carcinoma. Patients with grade 0 PVH developed BM at a rate 3.5-, 8.6-, and 3.6-fold higher rates than those with grade 1 (95% CI 1.4–9.0), 2 (95% CI 2.4–41.9), and 3 (95% CI 1.02–15.0), respectively. Lung cancer patients with grade 0 PVH on initial MR images have a high subsequent incidence of BM. PVH is a useful method for evaluating risk of BM.

Predicting brain metastases for non-small cell lung cancer based on magnetic resonance imaging

In this study the relationship between brain structure and brain metastases (BM) occurrence was analyzed. A model for predicting the time of BM onset in patients with non-small cell lung cancer (NSCLC) was proposed. Twenty patients were used to develop the model, whereas the remaining 69 were used for independent validation and verification of the model. Magnetic resonance images were segmented into cerebrospinal fluid, gray matter (GM), and white matter using voxel-based morphometry. Automatic anatomic labeling template was used to extract 116 brain regions from the GM volume. The elapsed time between the MRI acquisitions and BM diagnosed was analyzed using the least absolute shrinkage and selection operator method. The model was validated using the leave-one-out cross validation (LOOCV) and permutation test. The GM volume of the extracted 11 regions of interest increased with the progression of BM from NSCLC. LOOCV test on the model indicated that the measured and predicted BM onset were highly correlated (r = 0.834, P = 0.0000). For the 69 independent validating patients, accuracy, sensitivity, and specificity of the model for predicting BM occurrence were 70, 75, and 66%, respectively, in 6 months and 74, 82, and 60%, respectively, in 1 year. The extracted brain GM volumes and interval times for BM occurrence were correlated. The established model based on MRI data may reliably predict BM in 6 months or 1 year. Further studies with larger sample size are needed to validate the findings in a clinical setting.

Gadodiamide and Dentate Nucleus T1 Hyperintensity in Patients With Meningioma Evaluated by Multiple Follow-Up Contrast-Enhanced Magnetic Resonance Examinations With No Systemic Interval Therapy

The dentate nucleus of the cerebellum may appear as hyperintense on unenhanced T1 magnetic resonance images (MRIs) of the brain. Recently, T1 signal hyperintensity has received attention owing to data on the association of this finding with the history of multiple injections of gadolinium-based contrast agents, specifically gadodiamide, in patients with multiple sclerosis and brain metastases. We conducted a retrospective study on patients with a meningioma who had routinely undergone follow-up enhanced MRI scans with gadodiamide. Across a time interval of 18 months (from January 2013 to July 2014), we identified 102 consecutive patients eligible for this study. A significant increase in T1 hyperintensity of the dentate nuclei of the cerebellum on nonenhanced scans was observed between the first and the last MRI in the group of patients with a history of at least 6 enhanced MRI scans (P < 0.01), whereas no differences were observed in the group with 1 to 5 enhanced MRI scans (P = 0.74). Further research is necessary to shed light on the mechanism of the T1 hyperintensity as well as on the histological and microstructural appearance of the dentate nucleus after multiple intravenous injections of gadodiamide. The finding raises the question of substantial dechelation of this agent in patients with normal renal function.