Publications by authors named "Rebecca Rakow-Penner"

Article Synopsis
  • The BI-RADS category 3 assessment indicates findings that are "probably benign," with a less than 2% chance of being cancerous, helping to reduce unnecessary breast biopsies.
  • Despite its established guidelines for mammography, breast ultrasound, and emerging MRI uses, there is still confusion and misuse surrounding this category.
  • Category 3 findings should be followed up with short-term imaging to monitor for changes, and it is not appropriate to use in screening studies without further diagnostic evaluations.
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Article Synopsis
  • The study aims to create a calibration technique to standardize echo times (TE) for using restriction spectrum imaging (RSI) as a biomarker for detecting significant prostate cancer.
  • Researchers analyzed data from 197 patients, with a focus on 97 diagnosed with clinically significant prostate cancer, to compare RSI measurements taken at different TE values.
  • Results showed that calibration significantly reduced errors in RSI measurements, improving sensitivity to 66% and specificity to 72% in classifying clinically significant prostate cancer.
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Prostate MRI has traditionally relied on qualitative interpretation. However, quantitative components hold the potential to markedly improve performance. The ADC from DWI is probably the most widely recognized quantitative MRI biomarker and has shown strong discriminatory value for clinically significant prostate cancer (csPCa) as well as for recurrent cancer after treatment.

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Background: Breast cancer screening with dynamic contrast-enhanced MRI (DCE-MRI) is recommended for high-risk women but has limitations, including variable specificity and difficulty in distinguishing cancerous (CL) and high-risk benign lesions (HRBL) from average-risk benign lesions (ARBL). Complementary non-invasive imaging techniques would be useful to improve specificity.

Purpose: To evaluate the performance of a previously-developed breast-specific diffusion-weighted MRI (DW-MRI) model (BS-RSI3C) to improve discrimination between CL, HRBL, and ARBL in an enriched screening population.

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The diagnosis of a common cause of chronic pelvic pain can be made by visualizing reflux in the ovarian veins. Fluoroscopic venography is the gold standard for diagnosing ovarian vein reflux, but it is an invasive technique that exposes patients to ionizing radiation. MRI, with its lack of ionizing radiation and capability of high-temporal and spatial-resolution vascular imaging, has the potential to provide similar diagnostic information.

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Purpose: MRI is commonly used to aid breast cancer diagnosis and treatment evaluation. For patients with breast cancer, neoadjuvant chemotherapy aims to reduce the tumor size and extent of surgery necessary. The current clinical standard to measure breast tumor response on MRI uses the longest tumor diameter.

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Article Synopsis
  • High b-value diffusion-weighted images (DWI) are used to detect clinically significant prostate cancer (csPCa), and this study compares synthesized DWI (sDWI) to acquired DWI (aDWI) in this context.
  • The study involved 151 patients and used various b-values (0, 500, 1000, and 2000 s/mm) to assess differences in signal intensity and classification accuracy for detecting csPCa.
  • Results showed that while sDWI is similar to aDWI qualitatively, it introduced artifacts in surrounding tissue that hinder cancer detection, with a previously validated biomarker (RSIrs) proving to be more effective for identifying csPCa.
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Purpose: The focal radiation therapy (RT) boost technique was shown in a phase III randomized controlled trial (RCT) to improve prostate cancer outcomes without increasing toxicity. This technique relies on the accurate delineation of prostate tumors on MRI. A recent prospective study evaluated radiation oncologists' accuracy when asked to delineate prostate tumors on MRI and demonstrated high variability in tumor contours.

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The diagnosis, treatment, and management of gynecologic malignancies benefit from both positron emission tomography/computed tomography (PET/CT) and MRI. PET/CT provides important information on the local extent of disease as well as diffuse metastatic involvement. MRI offers soft tissue delineation and loco-regional disease involvement.

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Background: In breast diffusion-weighted imaging (DWI), distortion and physiologic artifacts affect clinical interpretation. Image quality can be optimized by addressing the effect of phase encoding (PE) direction on these artifacts.

Purpose: To compare distortion artifacts in breast DWI acquired with different PE directions and polarities, and to discuss their clinical implications.

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Background: Restriction Spectrum Imaging restriction score (RSIrs) is a quantitative biomarker for detecting clinically significant prostate cancer (csPCa). However, the quantitative value of the RSIrs is affected by imaging parameters such as echo time (TE).

Purpose: The purpose of the present study is to develop a calibration method to account for differences in echo times and facilitate use of RSIrs as a quantitative biomarker for the detection of csPCa.

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Purpose: Dynamic contrast-enhanced MRI (DCE) and apparent diffusion coefficient (ADC) are currently used to evaluate treatment response of breast cancer. The purpose of the current study was to evaluate the three-component Restriction Spectrum Imaging model (RSI), a recent diffusion-weighted MRI (DWI)-based tumor classification method, combined with elastic image registration, to automatically monitor breast tumor size throughout neoadjuvant therapy.

Experimental Design: Breast cancer patients (27) underwent multi-parametric 3T MRI at four time points during treatment.

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Purpose: In a phase III randomized trial, adding a radiation boost to tumor(s) visible on MRI improved prostate cancer (PCa) disease-free and metastasis-free survival without additional toxicity. Radiation oncologists' ability to identify prostate tumors is critical to widely adopting intraprostatic tumor radiotherapy boost for patients. A diffusion MRI biomarker, called the Restriction Spectrum Imaging restriction score (RSIrs), has been shown to improve radiologists' identification of clinically significant PCa.

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Article Synopsis
  • High-value diffusion-weighted images (DWI) are crucial for detecting clinically significant prostate cancer (csPCa), leading to synthesis of DWI to enhance efficiency and image quality.* -
  • This study retrospectively compared synthesized DWI (sDWI) to acquired DWI (aDWI) in 151 patients, using various b-values, and assessed their effectiveness in predicting csPCa.* -
  • Results showed that while sDWI has some qualitative similarities to aDWI, its accuracy and image quality are worse than aDWI and a validated biomarker, indicating limitations in using synthesized images for csPCa detection.*
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Breast cancer is the most common malignancy in women, and for women under 40, it is the leading cause of cancer-related deaths. A specific type of breast cancer is pregnancy-associated breast cancer, which is diagnosed during pregnancy, the first-year postpartum, or during lactation. Pregnancy-associated breast cancer is seen in 3/1000 pregnancies and is increasing in incidence as women delay pregnancy.

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Purpose To develop a multicompartmental signal model for whole-body diffusion-weighted imaging (DWI) and apply it to study the diffusion properties of normal tissue and metastatic prostate cancer bone lesions in vivo. Materials and Methods This prospective study (: NCT03440554) included 139 men with prostate cancer (mean age, 70 years ± 9 [SD]). Multicompartmental models with two to four tissue compartments were fit to DWI data from whole-body scans to determine optimal compartmental diffusion coefficients.

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Background: Multiparametric magnetic resonance imaging (mpMRI) improves detection of clinically significant prostate cancer (csPCa), but the subjective Prostate Imaging Reporting and Data System (PI-RADS) system and quantitative apparent diffusion coefficient (ADC) are inconsistent. Restriction spectrum imaging (RSI) is an advanced diffusion-weighted MRI technique that yields a quantitative imaging biomarker for csPCa called the RSI restriction score (RSI).

Objective: To evaluate RSI for automated patient-level detection of csPCa.

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Background: To date, the accuracy and variability of diffusion-weighted MRI (DW-MRI) metrics have been reported in a limited number of scanner/protocol/coil combinations.

Purpose: To evaluate the reproducibility of DW-MRI estimates across multiple scanners and DW-MRI protocols and to assess the effects of using an 8-channel vs. 16-channel breast coil in a breast phantom.

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The role of diffusion weighted imaging (DWI) as a biomarker has been the subject of active investigation in the field of breast radiology. By quantifying the random motion of water within a voxel of tissue, DWI provides indirect metrics that reveal cellularity and architectural features. Studies show that data obtained from DWI may provide information related to the characterization, prognosis, and treatment response of breast cancer.

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Diffusion-weighted MRI (DW-MRI) offers a potential adjunct to dynamic contrast-enhanced MRI to discriminate benign from malignant breast lesions by yielding quantitative information about tissue microstructure. Multi-component modeling of the DW-MRI signal over an extended -value range (up to 3000 s/mm) theoretically isolates the slowly diffusing (restricted) water component in tissues. Previously, a three-component restriction spectrum imaging (RSI) model demonstrated the ability to distinguish malignant lesions from healthy breast tissue.

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Diffusion-weighted magnetic resonance imaging (DWI) of the musculoskeletal system has various applications, including visualization of bone tumors. However, DWI acquired with echo-planar imaging is susceptible to distortions due to static magnetic field inhomogeneities. This study aimed to estimate spatial displacements of bone and to examine whether distortion corrected DWI images more accurately reflect underlying anatomy.

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Article Synopsis
  • This study aimed to develop a restriction spectrum imaging (RSI) model specifically for breast tissues by analyzing their diffusion-weighted MRI signals using a combination of known apparent diffusion coefficients (ADCs).
  • The research involved scanning 74 women with breast cancer using a 3.0 Tesla MRI and found that a triexponential model more effectively characterized the diffusion signal compared to traditional methods. The results indicated significant differences in the diffusion signal between tumor and healthy tissues.
  • The conclusion highlights that the triexponential RSI model can identify tumors with a level of clarity similar to dynamic contrast-enhanced (DCE) imaging, without the need for additional contrast agents, potentially aiding in distinguishing between healthy and malignant
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