Equilibrium radionuclide angiocardiography: Its usefulness in current practice and potential future applications

Supra-Normal Left Ventricular Function

Heart failure (HF) is often categorized by left ventricular (LV) ejection fraction (LVEF). A new category of HF characterized by supra-normal LVEF (>65%), named HF with supra-normal ejection fraction (HFsnEF), has been recently proposed. Some studies reported that patients with supra-normal LVEF might have an increased risk of long-term major adverse cardiovascular events and U-shaped mortality patterns. Currently, the prognosis of HFsnEF is not well established but seems to be associated with an increased risk of long-term major adverse cardiovascular events. It has been reported that HFsnEF is more prevalent in women and is associated with higher prevalence of nonischemic HF, higher blood urea nitrogen plasma levels, lower levels of natriuretic peptides, and to be less likely treated with β blockers. The pathophysiology of HFsnEF would be associated with microvascular dysfunction because of microvascular inflammation or reduced coronary flow reserve, and low stroke volume index with smaller cardiac chamber dimensions and concentric LV geometry. In this study, we systematically reviewed published data on patients with s supra-normal LV function and reported its definition, proposed pathophysiology, phenotypes, diagnostic strategy, and prognosis.

Challenges in Cardiovascular Imaging in Women with Breast Cancer

Cardiovascular imaging in breast cancer patients is paramount for the surveillance of cancer therapy-related cardiac dysfunction (CTRCD); however, it comes with specific limitations. PURPOSE OF REVIEW: This review aims to describe the unique challenges faced in cardiovascular imaging of breast cancer patients, discuss evidence to support the utility of various imaging modalities, and provide solutions for improvement in imaging this unique population. RECENT FINDINGS: Updated clinical society guidelines have introduced more unifying surveillance of CTRCD, although there remains a lack of a universally accepted definition. Traditional and novel multi-modality imaging can be used to detect CTRCD and myocarditis in breast cancer patients. Cardiovascular imaging in breast cancer patients is difficult due to reconstructive surgery. Although echocardiography with myocardial strain is the cornerstone, multi-modality imaging can be used to evaluate for CTRCD and myocarditis. Novel imaging techniques to improve the diagnosis of cardiotoxicities in breast cancer patients are needed.

Imaging in Heart Failure with Preserved Ejection Fraction: A Multimodality Imaging Point of View

Heart failure with preserved ejection fraction (HFpEF) is an important global health problem. Despite increased prevalence due to improved diagnostic options, limited improvement has been achieved in cardiac outcomes. HFpEF is an extremely complex syndrome and multimodality imaging is important for diagnosis, identifying its different phenotypes and determining prognosis. Evaluation of left ventricular filling pressures using echocardiographic diastolic function parameters is the first step of imaging in clinical practice. The role of echocardiography is becoming more popular and with the recent developments in deformation imaging, cardiac MRI is extremely important as it can provide tissue characterisation, identify fibrosis and optimal volume measurements of cardiac chambers. Nuclear imaging methods can also be used in the diagnosis of specific diseases, such as cardiac amyloidosis.

Left ventricular ejection fraction by multigated acquisition scan using planar sodium iodide and cadmium-zinc-telluride cameras: a comparison with two-dimensional echocardiography

Objectives

This study was undertaken to compare the correlation and agreement between Modified Simpson's method two-dimensional-echocardio-graphy (2D-echo) and rest multigated acquisition scan (MUGA) using both planar sodium iodide (pNaI) and cadmium-zinc-telluride (CZT) cameras to measure left ventricular ejection fraction (LVEF).

Methods

One hundred and nine breast cancer patients monitored for cardiotoxicity underwent 2D-echo, followed by pNaI and CZT MUGA scans on the same day. LVEF for CZT camera was processed using both automatic and manual processing methods, thus yielding four methods for the LVEF analysis.

Results

Significant correlation (p<0.01) was seen among all four methods, with varied correlation strengths. Moderate correlation was seen between 2D-echo and both pNaI (r=0.56) and CZT cameras (automatic r=0.54, manual r=0.56). Strong correlation was registered between pNaI and CZT camera (automatic r=0.72, manual r=0.71). Bland-Altman limits of agreement among the three scans were wide and suboptimal. The widest limits were -21.1 to +16.2 (37%) between 2D-echo and CZT auto-processing.

Conclusion

Any one of the modalities can be used to measure LVEF, however, their results should not be used interchangeably. The same method of measurement is advised for serial scans.

Direct Cell Radiolabeling for in Vivo Cell Tracking with PET and SPECT Imaging

The arrival of cell-based therapies is a revolution in medicine. However, its safe clinical application in a rational manner depends on reliable, clinically applicable methods for determining the fate and trafficking of therapeutic cells in vivo using medical imaging techniques─known as in vivo cell tracking. Radionuclide imaging using single photon emission computed tomography (SPECT) or positron emission tomography (PET) has several advantages over other imaging modalities for cell tracking because of its high sensitivity (requiring low amounts of probe per cell for imaging) and whole-body quantitative imaging capability using clinically available scanners. For cell tracking with radionuclides, ex vivo direct cell radiolabeling, that is, radiolabeling cells before their administration, is the simplest and most robust method, allowing labeling of any cell type without the need for genetic modification. This Review covers the development and application of direct cell radiolabeling probes utilizing a variety of chemical approaches: organic and inorganic/coordination (radio)chemistry, nanomaterials, and biochemistry. We describe the key early developments and the most recent advances in the field, identifying advantages and disadvantages of the different approaches and informing future development and choice of methods for clinical and preclinical application.

Shining Damaged Hearts: Immunotherapy-Related Cardiotoxicity in the Spotlight of Nuclear Cardiology

The emerging use of immunotherapies in cancer treatment increases the risk of immunotherapy-related cardiotoxicity. In contrast to conventional chemotherapy, these novel therapies have expanded the forms and presentations of cardiovascular damage to a broad spectrum from asymptomatic changes to fulminant short- and long-term complications in terms of cardiomyopathy, arrythmia, and vascular disease. In cancer patients and, particularly, cancer patients undergoing (immune-)therapy, cardio-oncological monitoring is a complex interplay between pretherapeutic risk assessment, identification of impending cardiotoxicity, and post-therapeutic surveillance. For these purposes, the cardio-oncologist can revert to a broad spectrum of nuclear cardiological diagnostic workup. The most promising commonly used nuclear medicine imaging techniques in relation to immunotherapy will be discussed in this review article with a special focus on the continuous development of highly specific molecular markers and steadily improving methods of image generation. The review closes with an outlook on possible new developments of molecular imaging and advanced image evaluation techniques in this exciting and increasingly growing field of immunotherapy-related cardiotoxicity.

Nuclear medicine imaging methods of radiation-induced cardiotoxicity

Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening, which leads to early detection of breast cancer. Therefore, it is of utmost importance to prevent patients from long-term side effects, including radiotherapy-induced cardiotoxicity. Radiotherapy may contribute to damage of myocardial structures on the cellular level, which eventually could result in various types of cardiovascular problems, including coronary artery disease and (non-)ischemic cardiomyopathy, leading to heart failure. These cardiac complications of radiotherapy are preceded by alterations in myocardial perfusion and blood flow. Therefore, early detection of these alterations is important to prevent the progression of these pathophysiological processes. Several radionuclide imaging techniques may contribute to the early detection of these changes. Single-Photon Emission Computed Tomography (SPECT) cameras can be used to create Multigated Acquisition scans in order to assess the left ventricular systolic and diastolic function. Furthermore, SPECT cameras are used for myocardial perfusion imaging with radiopharmaceuticals such as ^99mTc-sestamibi and ^99mTc-tetrofosmin. Accurate quantitative measurement of myocardial blood flow (MBF), can be performed by Positron Emission Tomography (PET), as the uptake of some of the tracers used for PET-based MBF measurement almost creates a linear relationship with MBF, resulting in very accurate blood flow quantification. Furthermore, there are PET and SPECT tracers that can assess inflammation and denervation of the cardiac sympathetic nervous system. Research over the past decades has mainly focused on the long-term development of left ventricular impairment and perfusion defects. Considering laterality of the breast cancer, some early studies have shown that women irradiated for left-sided breast cancer are more prone to cardiotoxic side effects than women irradiated for right-sided breast cancer. The left-sided radiation field in these trials, which predominantly used older radiotherapy techniques without heart-sparing techniques, included a larger volume of the heart and left ventricle, leading to increased unavoidable radiation exposure to the heart due to the close proximity of the radiation treatment volume. Although radiotherapy for breast cancer exposes the heart to incidental radiation, several improvements and technical developments over the last decades resulted in continuous reduction of radiation dose and volume exposure to the heart. In addition, radiotherapy reduces loco-regional tumor recurrences and death from breast cancer and improves survival. Therefore, in the majority of patients, the benefits of radiotherapy outweigh the potential very low risk of cardiovascular adverse events after radiotherapy. This review addresses existing nuclear imaging techniques, which can be used to evaluate (long-term) effects of radiotherapy-induced mechanical cardiac dysfunction and discusses the potential use of more novel nuclear imaging techniques, which are promising in the assessment of early signs of cardiac dysfunction in selected irradiated breast cancer patients.

Impact of curative parathyroidectomy on left ventricular functions assessed with 2D ECHO and MUGA study

Objective: Primary hyperparathyroidism (PHPT) is associated with increased cardiovascular morbidity and mortality with inconsistent results on the reversibility of cardiovascular changes after parathyroidectomy (PTx). The present study was undertaken to evaluate both structural and functional cardiac changes and their reversal after PTx in patients with PHPT.

Material and Methods: Thirty patients of symptomatic PHPT without cardiovascular risk factors were evaluated prospectively by means of 2D echocar- diography (ECHO) and Multigated Acquisition (MUGA) study before surgery and six months after curative parahyroidectomy.

Results: Nine of 30 patients had hypertension which improved in two after PTx (p 0.20). Two patients had left ventricle hypertrophy on 2D ECHO pre- operatively which improved after PTx (p< 0.001). Left ventricular ejection fraction (LVEF) did not show significant change before and after PTx on 2D ECHO. Nine out of 30 patients had hypertension which improved in two after PTx (p 0.20). Two patients with left ventricle hypertrophy on 2D ECHO preoperatively improved after PTx (p< 0.001). Left ventricular ejection fraction (EF) did not depict significant change before and after PTx on 2D ECHO. Whereas, four out of six patients with preoperative EF <50% representing systolic dysfunction on MUGA study showed improvement after PTx. On 2D ECHO, eight patients depicted diastolic dysfunction which improved in six patients after curative surgery (p= 0.07). However, on MUGA study, 13 pa- tients presented with tTPF >180 ms indicating diastolic dysfunction, of which ten showed improvement after PTx (p= 0.007).

Conclusion: The present study analyzed preoperative and postoperative cardiac function using both 2D ECHO and MUGA study. MUGA study provided a more objective assessment of the cardiac function by determining left ventricular ejection fraction and diastolic dysfunction.

Exploring the potential utilities of 99mTc-labeled RBC-equilibrium radionuclide angiocardiography in transfusion-dependent β-thalassemia major patients

AIMS

99mTc-labeled RBC-equilibrium radionuclide angiocardiography (ERNA) is done in transfusion-dependent beta-thalassemia major (β-TM) patients routinely for cardiac dysfunction. This prospective study aimed at evaluating the potential of ERNA in demonstrating the bone marrow hyperplasia as an adjunct biomarker for monitoring the adequacy of blood transfusions in transfusion-dependent β-TM patients.

MATERIALS AND METHODS

One hundred and twenty-six patients of β-TM (study group) and 30 nonthalassemic patients (control) underwent ERNA study with an additional whole-body imaging. We quantitated the normalized bone marrow tracer uptake (due to marrow hyperplasia) and hepatic tracer uptake (indicator of hepatic perfusion) in both the groups on whole-body imaging. Liver and myocardial iron deposition were evaluated with T2* MRI in the thalassemic group.

RESULTS

β-TM group showed significantly increased mean normalized marrow count (MN) compared to the control group (P < 0.001) reflecting peripheral marrow hyperplasia (indirect marker for blood transfusion inadequacy). The hematological parameters in the study group showed a negative correlation with MN, without such correlation in the control group. The study group showed greater derangement in hepatic perfusion with significantly less mean normalized hepatic tracer uptake (HN) compared to the control group. Hepatic iron deposition (evaluated with T2* MRI) also showed a negative correlation with hepatic perfusion parameter (HN) assessed by ERNA, though myocardial iron deposition did not show any significant correlation with cardiac systolic/diastolic parameters evaluated by ERNA in the study group.

CONCLUSION

ERNA study with these novel parameters (MN and HN) may have the potential to assess peripheral marrow hyperplasia and derangement in hepatic perfusion in transfusion-dependent β-TM.

New approach for quantification of left ventricular function from low-dose gated bloodpool SPECT: Validation and comparison with conventional methods in patients

BACKGROUND

Planar equilibrium radionuclide angiocardiography (ERNA) has been used as the gold standard for assessment of left ventricular (LV) function for over three decades. However, this imaging modality has recently gained less favor due to growing concerns about radiation exposure. We developed a novel approach that involves integrating short axis slices of gated bloodpool SPECT for quantification of LV function with improved signal-to-noise ratio and reduced radioactive dose while maintaining image quality and quantitative precision.

METHODS

Twenty patients referred for ERNA underwent standard in vitro 99mTc-labeling of red blood cells (RBC), and were initially imaged following a low-dose (~ 8 mCi) injection using a dedicated cardiac SPECT camera, and then had planar imaging following a high-dose (~ 25 mCi) injection. Four different quantification methods were utilized to assess the LV function and were compared for quantitative precision and inter-observer reproducibility of the quantitative assessments.

RESULTS

The Yale method resulted in the most consistent assessment of LV function compared with the gold standard high-dose ERNA method, along with excellent inter-observer reproducibility.

CONCLUSIONS

The new low-dose 99mTc-RBC imaging method provides precise quantification of LV function with a greater than 67% reduction in dose and may potentially improve assessment of regional function.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune effector cell-related adverse events

Immune effector cell (IEC) therapies offer durable and sustained remissions in significant numbers of patients with hematological cancers. While these unique immunotherapies have improved outcomes for pediatric and adult patients in a number of disease states, as 'living drugs,' their toxicity profiles, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), differ markedly from conventional cancer therapeutics. At the time of article preparation, the US Food and Drug Administration (FDA) has approved tisagenlecleucel, axicabtagene ciloleucel, and brexucabtagene autoleucel, all of which are IEC therapies based on genetically modified T cells engineered to express chimeric antigen receptors (CARs), and additional products are expected to reach marketing authorization soon and to enter clinical development in due course. As IEC therapies, especially CAR T cell therapies, enter more widespread clinical use, there is a need for clear, cohesive recommendations on toxicity management, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of common toxicities in the context of IEC treatment, including baseline laboratory parameters for monitoring, timing to onset, and pharmacological interventions, ultimately forming evidence- and consensus-based recommendations to assist medical professionals in decision-making and to improve outcomes for patients.

The influence of anthropometric and basic circulatory variables on count rate in cadmium-zinc-telluride SPECT gated radionuclide angiography

AIM

To determine the influence of weight, height, gender, age, heart rate, and blood pressure on count rate in cadmium-zinc-telluride single-photon emission computed tomography (CZT SPECT) gated radionuclide angiography.

METHOD

A total of 1,065 eligible patients referred for routine assessment of left ventricular ejection fraction were registered from August 2015 to November 2016. Data were recorded on heart rate, systolic and diastolic blood pressure, age, gender, height, weight, and count rate. All radionuclide angiographies were performed on a dedicated cardiac CZT SPECT camera, GE Discovery 530c. A dose of 550 MBq 99mTc-labeled human serum albumin was administered intravenously to each patient.

RESULTS

Count rate varied from 1.2 to 8.9 counts per second. All test variables were significantly associated with count rate. From the preliminary analysis, weight appeared as the main contributing factor for explaining the variations in count rate with and R2 of 0.68. A model consisting of weight, height, gender, and age explains 75% of the variance in count rate.

CONCLUSION

Patient height, weight, gender, and age have significant impact on count rate when performing CZT radionuclide angiography and may subsequently be used for individualized planning of tracer dosage.

Assessment of Left Ventricular Ejection Fraction by Thallium-201 Myocardial SPECT-CT in Patients with Angina Pectoris: Comparison with 2D Echocardiography

Purpose

Left ventricular (LV) ejection fraction (EF) is an important parameter for assessing cardiac systolic function and predicting prognosis in patients with cardiovascular disease. The aim of this study was to evaluate the feasibility of assessing LVEF by Tl-201 hybrid myocardial single-photon emission computed tomography (SPECT)/CT using two attenuation correction methods in patients with angina pectoris.

Methods

A total of 339 patients with angina pectoris (62.8 ± 12.9 years, male:female = 206:133) were analyzed. All patients underwent Tl-201 myocardial SPECT/CT and transthoracic two-dimensional (2D) echocardiograph. We compared LVEF assessed by SPECT/CT using two attenuation correction methods: CT-based attenuation correction (CTAC) and non-attenuation correction (non-AC) methods and 2D echocardiography.

Results

LVEF assessed by either of the two attenuation correction techniques and 2D echocardiography showed moderate correlation in all patients with angina pectoris (r = 0.487 for CTAC and r = 0.473 for non-AC, p < 0.001). Results were similar in the subgroup of patients with perfusion abnormalities on myocardial SPECT/CT images. Overall diagnostic performances were similar for the CTAC and non-AC methods for evaluating normal and decreased LVEF by myocardial SPECT/CT.

Conclusion

LVEF measured by the CTAC method of Tl-201-gated myocardial SPECT/CT was comparable with the conventional non-AC method in patients with angina pectoris and in the subgroup of patients with perfusion abnormality. Tl-201-gated myocardial hybrid SPECT/CT can be a reliable tool in the assessment of LVEF in clinic.

Diastolic dysfunction can precede systolic dysfunction on MUGA in cancer patients receiving trastuzumab-based therapy

Background

Trastuzumab (T) and anthracycline (A)-based chemotherapy is considered the standard of care in human epidermal growth factor receptor-2+ overexpressing breast cancer, but requires monitoring for known cardiotoxicity using left ventricular (LV) ejection fraction (EF) every 3–4 months during treatment. It is not conclusively established whether diastolic dysfunction (DD) precedes LVEF decrease in patients developing trastuzumab-induced cardiotoxicity (TIC).

Objective

The aim was to elucidate whether DD precedes LVEF decrease in trastuzumab-treated patients being monitored with radionuclide multigated acquisition for TIC.

Patients and methods

Patients treated with T±A-based chemotherapy who had undergone multigated acquisition were selected by date range (January 2006–September 2015). Up to four scans were analyzed per patient: (a) pre-A therapy, (b) pre-T therapy, (c) 4 months into T therapy, and (d) at end of T therapy. Baseline referred to the first scan of each patient (i.e. pre-A or pre-T). LV systolic and DD were defined as follows: EF less than 50% or a 10-point decrease from baseline and LV peak filling rate (PFR) less than 2.5 end-diastolic volume/s and time to peak LV filling rates (TPFR) greater than 180 ms, respectively.

Results

A total of 202 patients were screened for this study, of whom 153 had received A therapy (5.1±4.1 months duration) before T, 192 had 4 months of follow-up data, and 146 had 4 months of follow-up data and beyond (10.5±5.0 months). LVEF decreased with A and T therapy (P<0.005), but remained stable between 4 months and the final exam (P=0.26). In patients with normal diastolic function at baseline (45.5%), PFR decreased with A and T, and DD preceded SD by 73 days on average. In the remaining patients, with abnormal diastolic function at baseline (54.5%), PFR did not change over the course of treatment (P>0.1), nor did TPFR (P>0.3).

Conclusion

Patients with normal diastolic function at baseline receiving trastuzumab±anthracycline adjuvant therapy may develop DD before SD, therefore offering an opportunity for early referral to cardiologists to optimize cardiovascular risk factors and manage cardiotoxicity.

Biomarkers for monitoring chemotherapy-induced cardiotoxicity

Cardiotoxicity, including acute and late-onset cardiotoxicity, is a well-known adverse effect of many types of antitumor agents. Early identification of patients with cardiotoxicity is important to ensure prompt treatment and minimize toxic effects. The etiology of chemotherapy-induced cardiotoxicity is multifactorial. Traditional methods for assessment of chemotherapy-induced cardiotoxicity typically involve serial measurements of cardiac function via multi-modality imaging techniques. Typically, however, significant left ventricular dysfunction has already occurred when cardiotoxicity is detected by imaging techniques. Biomarkers, most importantly cardiac natriuretic peptides and troponins, are promising markers for identifying patients potentially at risk for clinical heart failure symptoms. This review summarizes the recent progress in clinical utilization of biomarkers for early diagnosis of acute cardiotoxicity and for prediction of late-onset cardiotoxicity. We also discuss the conflicting results of different studies and the association of results with study design.

Does diastolic dysfunction precede systolic dysfunction in trastuzumab-induced cardiotoxicity? Assessment with multigated radionuclide angiography (MUGA)

BACKGROUND

Trastuzumab is successfully used for the treatment of HER2-positive breast cancer. Because of its association with cardiotoxicity, LVEF is monitored by MUGA, though this is a relatively late measure of cardiac function. Diastolic dysfunction (DD) is believed to be an early predictor of cardiac impairment. We evaluate the merit of MUGA-derived diastolic function parameters in the early detection of trastuzumab-induced cardiotoxicity (TIC).

METHODS AND RESULTS

77 trastuzumab-treated patients with normal baseline systolic and diastolic function were retrospectively selected (n = 77). All serial MUGA examinations were re-analyzed for systolic and diastolic function parameters. 36 patients (47%) developed SD and 45 patients (58%) DD during treatment. Both systolic and diastolic parameters significantly decreased. Of the patients with SD, 24 (67%) also developed DD. DD developed prior to systolic impairment in 54% of cases, in 42% vice versa, while time to occurrence did not differ significantly (P = .52). This also applied to the subgroup of advanced stage breast cancer patients (P = .1).

CONCLUSIONS

Trastzumab-induced SD and DD can be detected by MUGA. An impairment of MUGA-derived diastolic parameters does not occur prior to SD and therefore cannot be used as earlier predictors of TIC.

Pre-chemotherapy values for left and right ventricular volumes and ejection fraction by gated tomographic radionuclide angiography using a cadmium-zinc-telluride detector gamma camera

BACKGROUND

Estimation of left ventricular ejection fraction (LVEF) using equilibrium radionuclide angiography is an established method for assessment of left ventricular function. The purpose of this study was to establish normative data on left and right ventricular volumes and ejection fraction, using cadmium-zinc-telluride SPECT camera.

METHODS AND RESULTS

From routine assessments of left ventricular function in 1172 patients, we included 463 subjects (194 men and 269 women) without diabetes, previous potentially cardiotoxic chemotherapy, known cardiovascular or pulmonary disease. The lower limits defined as mean value minus two standard deviations for ventricular ejection fraction and end diastolic volume were LVEF (men: 50%, women: 50%), LEDV (men: 45 mL, women: 40 mL), RVEF (men: 29%, women: 28%), and REDV (men: 73 mL, women: 57 mL).There was a significant negative correlation between age and both left and right ventricular volumes in women (r = -0.4, P < .001) but only for right end systolic ventricular volume in men (r = -0.3, P = .001).

CONCLUSION

A set of reference values for cardiac evaluation prior to chemotherapy in cancer patients without other known cardiopulmonary disease is presented. There are age-related changes in cardiac dimensions with age depending on gender, although with only limited influence on LVEF or RVEF.

Nuclear imaging for cardiac amyloidosis

Histological analysis of endomyocardial tissue is still the gold standard for the diagnosis of cardiac amyloidosis, but has its limitations. Accordingly, there is a need for non-invasive modalities to diagnose cardiac amyloidosis. Echocardiography and ultrasound and magnetic resonance imaging can show characteristics which may not be very specific for cardiac amyloid. Nuclear medicine has gained a precise role in this context: several imaging modalities have become available for the diagnosis and prognostic stratification of cardiac amyloidosis during the last two decades. The different classes of radiopharmaceuticals have the potential to bind different constituents of the amyloidotic infiltrates, with some relevant differences among the various aetiologic types of amyloidosis and the different organs and tissues involved. This review focuses on the background of the commonly used modalities, their present clinical applications, and future clinical perspectives in imaging patients with (suspected) cardiac amyloidosis. The main focus is on conventional nuclear medicine (bone scintigraphy, cardiac sympathetic innervation) and positron emission tomography.

Clinical utility of quantitative imaging

Quantitative imaging (QI) is increasingly applied in modern radiology practice, assisting in the clinical assessment of many patients and providing a source of biomarkers for a spectrum of diseases. QI is commonly used to inform patient diagnosis or prognosis, determine the choice of therapy, or monitor therapy response. Because most radiologists will likely implement some QI tools to meet the patient care needs of their referring clinicians, it is important for all radiologists to become familiar with the strengths and limitations of QI. The Association of University Radiologists Radiology Research Alliance Quantitative Imaging Task Force has explored the clinical application of QI and summarizes its work in this review. We provide an overview of the clinical use of QI by discussing QI tools that are currently used in clinical practice, clinical applications of these tools, approaches to reporting of QI, and challenges to implementing QI. It is hoped that these insights will help radiologists recognize the tangible benefits of QI to their patients, their referring clinicians, and their own radiology practice.