Ciprian Catana

Ciprian Catana
Massachusetts General Hospital | MGH · Department of Radiology

Doctor of Philosophy

About

184
Publications
25,719
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8,283
Citations
Citations since 2017
93 Research Items
5106 Citations
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201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000

Publications

Publications (184)
Chapter
The complementary anatomical and functional information obtained from separately performed magnetic resonance imaging (MRI) and positron emission tomography (PET) examinations have long been combined either by performing parallel analyses or by using software coregistration techniques to merge the two datasets. However, a major assumption that has...
Chapter
Motion degrades image quality, and biases data quantification in positron emission tomography (PET) studies. The MR data acquired using integrated PET/MR scanners can be used to characterize rigid and nonrigid body motion affecting PET studies. Given the simultaneous acquisition, estimates from MR-based motion characterization techniques can be app...
Article
The 68Ga-Collagen Binding Probe #8, 68Ga-CBP8, is a peptide-based, type I collagen-targeted probe developed for imaging of tissue fibrosis. The aim of this study was to determine the biodistribution, dosimetry, and pharmacokinetics of 68Ga-CBP8 in healthy human subjects. Methods: Nine healthy volunteers (5 male and 4 female) underwent whole-body 68...
Article
Objective: To compare standard (STD-DWI) single-shot echo-planar imaging DWI and simultaneous multislice (SMS) DWI during whole-body positron emission tomography (PET)/MRI regarding acquisition time, image quality, and lesion detection. Methods: Eighty-three adults (47 females, 57%), median age of 64 years (IQR 52-71), were prospectively enrolle...
Article
Background: Myocardial feature tracking (FT) provides a comprehensive analysis of myocardial deformation from cine balanced steady-state free-precession images (bSSFP). However, FT remains time-consuming, precluding its clinical adoption. Purpose: To compare left-ventricular global radial strain (GRS) and global circumferential strain (GCS) valu...
Article
Growing number of methods for attenuation-coefficient map estimation from magnetic resonance (MR) images have recently been proposed because of the increasing interest in MR-guided radiotherapy and the introduction of positron emission tomography (PET) MR hybrid systems. We propose a deep-network ensemble incorporating stochastic-binary-anatomical...
Article
Full-text available
Purpose To evaluate if a fully-automatic deep learning method for myocardial strain analysis based on magnetic resonance imaging (MRI) cine images can detect asymptomatic dysfunction in young adults with cardiac risk factors. Methods An automated workflow termed DeepStrain was implemented using two U-Net models for segmentation and motion tracking...
Article
While COVID-19 research has seen an explosion in the literature, the impact of pandemic-related societal and lifestyle disruptions on brain health among the uninfected remains underexplored. However, a global increase in the prevalence of fatigue, brain fog, depression and other “sickness behavior”-like symptoms implicates a possible dysregulation...
Article
Compartmental modeling analysis of 11C-raclopride (RAC) PET data can be used to measure the dopaminergic response to intra-scan behavioral tasks. Bias in estimates of binding potential (BPND) and its dynamic changes (ΔBPND) can arise both when head motion is present and when the compartmental model used for parameter estimation deviates from the un...
Article
Background and Purpose High-risk atherosclerosis is an underlying cause of cardiovascular events, yet identifying the specific patient population at immediate risk is still challenging. Here, we used a rabbit model of atherosclerotic plaque rupture and human carotid endarterectomy specimens to describe the potential of molecular fibrin imaging as a...
Article
Full-text available
Mothers are highly responsive to their offspring. In non-human mammals, mothers secrete dopamine in the nucleus accumbens (NAcc) in response to their pups. Yet, it is still unknown which aspect of the offspring-behavior elicits dopaminergic responses in mothers. Here we tested whether infants' affective signals elicit dopaminergic responses in the...
Article
Direct reconstruction methods have been developed to estimate parametric images directly from the measured PET sinograms by combining the PET imaging model and tracer kinetics in an integrated framework. Due to limited counts received, signal-to-noise-ratio (SNR) and resolution of parametric images produced by direct reconstruction frameworks are s...
Article
Objectives The authors present a novel technique to detect and characterize LAA thrombus in humans using combined positron emission tomography (PET)/cardiac magnetic resonance (CMR) of a fibrin-binding radiotracer, [⁶⁴Cu]FBP8. Background The detection of thrombus in the left atrial appendage (LAA) is vital in the prevention of stroke and is curren...
Article
We recently showed that patients with different chronic pain conditions (such as chronic low back pain, fibromyalgia, migraine, and Gulf War Illness) demonstrated elevated brain and/or spinal cord levels of the glial marker 18 kDa translocator protein, which suggests that neuroinflammation might be a pervasive phenomenon observable across multiple...
Article
Full-text available
Myocardial strain analysis from cinematic magnetic resonance imaging (cine-MRI) data provides a more thorough characterization of cardiac mechanics than volumetric parameters such as left-ventricular ejection fraction, but sources of variation including segmentation and motion estimation have limited its wider clinical use. We designed and validate...
Article
Attenuation correction (AC) remains a challenge in pelvis PET/MR imaging. In addition to the segmentation/model-based approaches, deep learning methods have shown promise in synthesizing accurate pelvis attenuation maps (μ-maps). However, these methods often misclassify air pockets in the digestive tract, which can introduce bias in the reconstruct...
Article
Full-text available
Positron emission tomography and magnetic resonance imaging (PET/MRI) scanners cannot be qualified in the manner adopted for hybrid PET and computed tomography (CT) devices. The main hurdle with qualification in PET/MRI is that attenuation correction (AC) cannot be adequately measured in conventional PET phantoms due to the difficulty in converting...
Preprint
Compartmental modeling of 11C-raclopride (RAC) is commonly used to measure dopamine response to intra-scan behavioral tasks. Bias in estimates of binding potential (BPND) and its dynamic changes (ΔBPND) can arise when the selected compartmental model deviates from the underlying biology. In this work, we characterize the bias associated with assumi...
Preprint
Full-text available
Direct reconstruction methods have been developed to estimate parametric images directly from the measured PET sinograms by combining the PET imaging model and tracer kinetics in an integrated framework. Due to limited counts received, signal-to-noise-ratio (SNR) and resolution of parametric images produced by direct reconstruction frameworks are s...
Article
Full-text available
Mechanisms of neuroimmune and mitochondrial dysfunction have been repeatedly implicated in autism spectrum disorder (ASD). To examine these mechanisms in ASD individuals, we measured the in vivo expression of the 18 kDa translocator protein (TSPO), an activated glial marker expressed on mitochondrial membranes. Participants underwent scanning on a...
Article
Objective: The aim of this study was to compare the performance of positron emission tomography (PET)/magnetic resonance (MR) versus stand-alone PET and stand-alone magnetic resonance imaging (MRI) in the detection and characterization of suspected liver metastases. Materials and methods: This multi-institutional retrospective performance study...
Article
Full-text available
Background MR is an important imaging modality for evaluating musculoskeletal malignancies owing to its high soft tissue contrast and its ability to acquire multiparametric information. PET provides quantitative molecular and physiologic information and is a critical tool in the diagnosis and staging of several malignancies. PET/MR, which can take...
Preprint
11C-Raclopride (RAC) positron emission tomography (PET) is used to study dopamine response to pharmacological and behavioral challenges. Behavioral challenges produce smaller responses than pharmacological challenges and are more susceptible to sources of bias, including motion bias. The purpose of this study was to characterize the effect of motio...
Preprint
Full-text available
Myocardial strain analysis from cinematic magnetic resonance imaging (cine-MRI) data could provide a more thorough characterization of cardiac mechanics than volumetric parameters such as left-ventricular ejection fraction, but sources of variation including segmentation and motion estimation have limited its wide clinical use. We designed and vali...
Article
The current pandemic has created a situation where nuclear medicine practitioners and medical physicists read or process nuclear medicine images remotely from their home office. This article presents recommendations on the components and specifications when setting up a remote viewing station for nuclear medicine imaging.
Preprint
Full-text available
Rationale Histone deacetylases (HDACs) play a central role in cardiac hypertrophy and fibrosis in preclinical models. However, their impact in the human heart remains unknown. Objective We aimed to image HDAC expression in the human heart in vivo with PET-MR (positron emission tomography and magnetic resonance) using [ ¹¹ C]Martinostat, a novel ra...
Article
Full-text available
Background Hypoxia is a driver of treatment resistance in glioblastoma. Anti-angiogenic agents may transiently normalize blood vessels and decrease hypoxia before excessive pruning of vessels increases hypoxia. The time window of normalization is dose- and time-dependent. We sought to determine how VEGF blockade with bevacizumab modulates tumor vas...
Preprint
The detection of thrombus in the left atrial appendage (LAA) is vital in the prevention of stroke. We present a novel technique to detect and characterize LAA thrombus in humans using positron emission tomography (PET) of a fibrin-binding radiotracer, [ ⁶⁴ Cu]FBP8. Initial testing in healthy volunteers (n = 8) revealed that [ ⁶⁴ Cu]FBP8 was stable...
Article
Attenuation correction has been one of the main methodological challenges in the integrated positron emission tomography and magnetic resonance imaging (PET/MRI) field. As standard transmission or computed tomography approaches are not available in integrated PET/MRI scanners, MR-based attenuation correction approaches had to be developed. Aspects...
Article
Full-text available
Purpose Intrahepatic cholangiocarcinoma (ICC) is associated with a poor prognosis with surgical resection offering the best chance for long-term survival and potential cure. However, in up to 36% of patients who undergo surgery, more extensive disease is found at time of operation requiring cancellation of surgery. PET/MR is a novel hybrid technolo...
Article
Full-text available
Major surgery is associated with a systemic inflammatory cascade that is thought, in some cases, to contribute to transient and/or sustained cognitive decline, possibly through neuroinflammatory mechanisms. However, the relationship between surgery, peripheral and central nervous system inflammation, and post-operative cognitive outcomes remains un...
Article
Full-text available
It is a growing concern that outcomes of neuroimaging studies often cannot be replicated. To counteract this, the magnetic resonance (MR) neuroimaging community has promoted acquisition standards and created data sharing platforms, based on a consensus on how to organize and share MR neuroimaging data. Here, we take a similar approach to positron e...
Article
Full-text available
Background Myocardial oxygenation imaging could help determine the presence of microvascular dysfunction associated with increased cardiovascular risk. However, it is challenging to depict the potentially small oxygenation alterations with current noninvasive cardiac MRI blood oxygen level-dependent (BOLD) techniques. Purpose To demonstrate the car...
Article
Gadolinium‐based contrast agents (GBCAs) are used to provide diagnostic information in clinical magnetic resonance (MR) examinations. Gadolinium (Gd) has been detected in the brain, bone and skin of patients, months and years following GBCA administration, raising concerns about long term toxicity. Despite increased scrutiny, the concentration, che...
Article
Prüfung auf Herz und Nieren: PET mit Yttrium‐86 kann Auskunft geben über die Clearance und biologische Verteilung der in der Kernspintomographie verwendeten Kontrastmittel auf Gadoliniumbasis. Spuren von Kontrastmittel lassen sich in den Nieren von Nagetieren noch 48 h nach der Injektion nachweisen. Abstract Gadolinium‐based contrast agents (GBCAs...
Article
Purpose: Targeting tumor blood vessels is an attractive therapy in glioblastoma (GBM) but the mechanism of action of these agents and how they modulate delivery of concomitant chemotherapy is not clear in humans. We sought to elucidate how bevacizumab modulates tumor vasculature and the impact those vascular changes have on drug delivery in patien...
Article
Purpose: The first aim of this work is to present a novel deep convolution neural network (DCNN) multiplane approach and compare it to single-plane prediction of synthetic computed tomography (sCT) by using the real computed tomography (CT) as ground truth. The second aim is to demonstrate the feasibility of magnetic resonance imaging (MRI)-based...
Article
Full-text available
Purpose: To describe an unsupervised three-dimensional cardiac motion estimation network (CarMEN) for deformable motion estimation from two-dimensional cine MR images. Materials and methods: A function was implemented using CarMEN, a convolutional neural network that takes two three-dimensional input volumes and outputs a motion field. A smoothn...
Article
Since the introduction of simultaneous PET/MRI in 2011, there have been significant advancements. In this review, we highlight several technical advancements that have been made primarily in attenuation and motion correction and discuss the status of multiple clinical applications using PET/MRI. This review is based on the experience at the first P...
Article
Whole-body positron emission tomography (PET) scanners are not optimized for imaging small structures in the human brain. Several PET devices specifically designed for this task have been proposed either for stand-alone operation or as magnetic resonance (MR)-compatible inserts. The main distinctive features of some of the most recent concepts and...
Article
Objectives: We aim to develop molecular fibrin imaging as a tool to stratify high risk atherosclerotic carotid plaques. Here, we describe our results with a fibrin-specific probe [ ⁶⁸ Ga]CM-246 in two different experimental settings: ex vivo imaging of carotid endarterectomy specimens and in vivo / ex vivo imaging of atherosclerotic plaque rupture...
Article
Full-text available
Military personnel are often exposed to multiple instances of various types of head trauma. As a result, there has been increasing concern recently over identifying when head trauma has resulted in a brain injury and what, if any, long-term consequences those brain injuries may have. Efforts to develop equipment to protect soldiers from these long-...
Article
Full-text available
Recently deep neural networks have been widely and successfully applied in computer vision tasks and attracted growing interests in medical imaging. One barrier for the application of deep neural networks to medical imaging is the need of large amounts of prior training pairs, which is not always feasible in clinical practice. This is especially tr...
Article
Full-text available
Purpose: To compare the clinical performance of upper abdominal PET/DCE-MRI with and without concurrent respiratory motion correction (MoCo). Methods: MoCo PET/DCE-MRI of the upper abdomen was acquired in 44 consecutive oncologic patients and compared with non-MoCo PET/MRI. SUVmax and MTV of FDG-avid upper abdominal malignant lesions were assess...
Article
Recently, an exhaustive examination of 11 state of the art MR-based attenuation correction (AC) concluded that there are currently a few methods showing similar results compared to the gold-standard, CT-based AC. While the study presented a thorough portfolio of metrics to quantify accuracy (bias) and quality, it lacked one of the most important me...
Article
Full-text available
Fibromyalgia (FM) is a poorly understood chronic condition characterized by widespread musculoskeletal pain, fatigue, and cognitive difficulties. While mounting evidence suggests a role for neuroinflammation, no study has directly provided evidence of brain glial activation in FM. In this study, we conducted a Positron Emission Tomography (PET) stu...
Article
Full-text available
Whole-body attenuation correction (AC) is still challenging in combined PET/MR scanners. We describe Dixon-VIBE Deep Learning (DIVIDE), a deep learning network architecture that allows synthesizing pelvis pseudo-CT maps based only on the standard Dixon volumetric interpolated breath-hold examination (Dixon-VIBE) images currently acquired for AC in...
Preprint
Full-text available
Recently deep neural networks have been widely and successfully applied in computer vision tasks and attracted growing interests in medical imaging. One barrier for the application of deep neural networks to medical imaging is the need of large amounts of prior training pairs, which is not always feasible in clinical practice. In this work we propo...
Article
Full-text available
Presents corrections to the paper, ”Direct Patlak reconstruction from dynamic PET data using the kernel method,” (Gong, et al) IEEE Trans. Med. Imaging, Vol 37, No. 4, April 2018
Article
A main advantage of PET is that it provides quantitative measures of the radiotracer concentration, but its accuracy is confounded by several factors, including attenuation, subject motion, and limited spatial resolution. Using the information from one simultaneously acquired morphological MR sequence with embedded navigators, we propose an efficie...
Article
Purpose: To investigate advanced multi-modal methods for pseudo-CT generation from standard MRI sequences and to validate the results by IMRT and VMAT radiation therapy plans. We present two novel methods which employ key techniques to enhance pseudo-CTs and we investigate the impact on image quality and applicability for IMRT and VMAT therapy pla...
Article
Full-text available
Background: In radiotherapy, MR imaging is only used because it has significantly better soft tissue contrast than CT, but it lacks electron density information needed for dose calculation. This work assesses the feasibility of using pseudo-CT (pCT) generated from T1w/T2w MR for proton treatment planning, where proton range comparisons are performe...
Article
Objectives: There is a need for better stratification of atherosclerotic patients to identify individuals at high risk for a cardiovascular event. Two key hallmarks of plaque at high risk for rupture are intraplaque hemorrhage and evidence of prior rupture. The protein fibrin is strongly associated with both hemorrhage and rupture but it is not pre...
Article
Background: Subject motion in positron emission tomography (PET) studies leads to image blurring and artifacts; simultaneously acquired magnetic resonance imaging (MRI) data provides a means for motion correction (MC) in integrated PET/MRI scanners. Purpose: To assess the effect of realistic head motion and MR-based MC on static [18F]-fluorodeox...
Article
Full-text available
Positron emission tomography (PET) is a quantitative imaging modality, but the computation of standardized uptake values (SUVs) requires several instruments to be correctly calibrated. Variability in the calibration process may lead to unreliable quantitation. Sealed source kits containing traceable amounts of 68 Ge∕ 68 Ga were used to measure sign...
Article
Full-text available
Purpose: We present an approach for concurrent reconstruction of respiratory motion compensated abdominal DCE-MRI and PET data in an integrated PET/MR scanner. The MR and PET reconstructions share the same motion vector fields (MVFs) derived from radial MR data; the approach is robust to changes in respiratory pattern and do not increase the total...
Chapter
Simultaneous PET/MR imaging allows the use of motion estimates derived from one modality to perform motion compensation of the data acquired with the other technique. Some of the most recently proposed MR-based PET motion estimation and correction techniques will be discussed in this chapter. First, the MR-based techniques for head, respiratory, ca...
Article
Positron emission tomography (PET) is a quantitative imaging modality, but the computation of standardized uptake values (SUVs) requires several instruments to be correctly calibrated. Variability in the calibration process may lead to unreliable quantitation. Sealed source kits containing traceable amounts of [Formula: see text] were used to measu...
Article
Objective: To characterize [¹¹C]‐PBR28 brain uptake using positron emission tomography (PET) in people with amyotrophic lateral sclerosis (ALS), and primary lateral sclerosis (PLS). We have previously shown increased [¹¹C]‐PBR28 uptake in the precentral gyrus in a small group of ALS patients. Herein, we confirm our initial finding, study the longit...
Article
Full-text available
Positron Emission Tomography (PET) is a functional imaging modality widely used in oncology, cardiology, and neuroscience. It is highly sensitive, but suffers from relatively poor spatial resolution, as compared with anatomical imaging modalities, such as magnetic resonance imaging (MRI). With the recent development of combined PET/MR systems, we c...
Article
Full-text available
BACKGROUND Increases in contrast enhancement due to treatment related inflammation creates a significant clinical conundrum for neuro-oncologists. Our goal was to use simultaneous PBR28 PET-MRI to measure TSPO, a marker of microglia activation as well glioma cells, in patients with glioblastoma (GBM). METHODS In this pilot study, patients who rece...
Article
Full-text available
Pain interventions with no active ingredient, placebo, are sometimes effective in treating chronic pain conditions. Prior studies on the neurobiological underpinnings of placebo analgesia indicate endogenous opioid release and changes in brain responses and functional connectivity during pain anticipation and pain experience in healthy subjects. He...
Preprint
Full-text available
Parametric images provide insight into the spatial distribution of physiological parameters, but they are often extremely noisy, due to low SNR of tomographic data. Direct estimation from projections allows accurate noise modeling, improving the results of post-reconstruction fitting. We propose a method, which we name kinetic compressive sensing (...
Conference Paper
Full-text available
Parametric images provide insight into the spatial distribution of physiological parameters, but they are often extremely noisy, due to low SNR of tomographic data. Direct estimation from projections allows accurate noise modeling, improving the results of post-reconstruction fitting. We propose a method, which we name kinetic compressive sensing (...