Minimization of errors in biexponential <i>T</i><sub>2</sub> measurements of the prostate

Gilani, Nima; Rosenkrantz, Andrew B.; Malcolm, Paul; Johnson, Glyn

doi:10.1002/jmri.24870

Cited by 19 publications

(29 citation statements)

References 12 publications

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“…While the LWF is estimated reliably, estimation of short and long T 2 components is affected by the underlying tissue fractions and the TE distribution sampled . By only fitting to the even echoes to correct for stimulated echoes, the effective TE‐spacing in this study was 50 msec, which may have impinged on the accuracy of estimation of the short T 2 components.…”

Section: Discussionmentioning

confidence: 90%

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Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Carlin

Orton

Collins

et al. 2018

Magnetic Resonance Imaging

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Background Interpretation of diffusion in conjunction with T2‐weighted MRI is essential for assessing prostate cancer; however, the combination of apparent diffusion coefficient (ADC) with quantitative T2 mapping remains unexplored. Purpose To document the T2 components and ADC of untreated and irradiated nonmalignant prostate tissue as a measure of their glandular luminal and cellular compartments and to compare values with those of tumor. Study Type Prospective. Population Twenty‐four men with prostate cancer (14 untreated; 10 with biochemical recurrence following radiation therapy). Field Strength/Sequences Endorectal 3 T MRI including a 32‐echo gradient echo and spin echo (GRASE) and an 8 b‐value diffusion‐weighted sequence. Assessment Regions of interest were drawn on ADC maps and T2‐weighted images around focal lesions in areas of biopsy‐positive prostate cancer and in nonmalignant areas of untreated and irradiated peripheral zone (PZ), and untreated transitional zone (TZ). Multiecho T2 data were fitted with mono‐/biexponential decay and nonnegative least squares functions. The luminal water fraction (LWF) was derived. Statistical Tests The preference between mono‐ and biexponential decay was assessed using the Bayesian information criterion. Differences in fitted parameters between tissue types were compared (paired t‐test within groups, Kruskal–Wallis and Wilcoxon rank‐sum test between groups) and correlations between ADC and T2 components assessed (Spearman rank correlation test). Results LWF in tumor (0.09) was significantly lower than in PZ or TZ (0.27 and 0.18, P < 0.01, respectively), but tumor values were comparable to nonmalignant irradiated prostate (0.08). The short T2 relaxation rate was lower in tumor than in nonmalignant untreated or irradiated tissue (significant compared with TZ, P = 0.01). There was a strong correlation between LWF and ADC in normal untreated tissue (r = 0.88, P < 0.001). This relationship was absent in nonmalignant irradiated prostrate (r = –0.35, P = 0.42) and in tumor (r = –0.04, P = 0.88). Data Conclusion T2 components in conjunction with ADC can be used to characterize untreated and irradiated nonmalignant prostate and tumor. LWF is most useful at discriminating tumor in the untreated prostate. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:619–627.

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Section: Discussionmentioning

confidence: 90%

“…T 2 relaxation properties of normal prostatic tissue show a decay pattern that is multiexponential . The short T 2 component has been ascribed to water associated with the cellular compartment (epithelial and stromal cells), while the long T 2 component reflects the luminal space.…”

mentioning

confidence: 99%

Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Carlin

Orton

Collins

et al. 2018

Magnetic Resonance Imaging

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“…Although, multi-component T 2 in prostate has been shown before [6,7,8,9,10] only one recent study investigated the application of this technique for cancer diagnosis [10]; however, no direct correlation between MRI and histology has been published. In our study, we validated MR measurements with wholemount histology, and performed statistical analysis to assess the accuracy of this technique in the detection and grading of PCa.…”

Section: Discussionmentioning

confidence: 99%

“…Evidence of bi-exponential T 2 decay in prostate has previously been shown [6,7,8,9], and recently investigated for potential contribution to prostate cancer diagnosis [10]. In this study, we investigated the relationship between multi-exponential T 2 mapping and the histopathology of prostatic tissue through a direct comparison between MRI and wholemount histology.…”

Section: Introductionmentioning

confidence: 99%

Luminal Water Imaging: A New MR Imaging T2 Mapping Technique for Prostate Cancer Diagnosis

et al. 2017

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Purpose-To assess the feasibility of luminal water imaging (LWI), a quantitative T 2 -based MRI technique, for the detection and grading of prostatic cancer (PCa).Material and Methods-18 patients with biopsy proven PCa provided informed consent to be included in this institutional human ethics board approved prospective study between January 2015, and January 2016. Patients underwent 3T MRI shortly before radical prostatectomy. T 2 distributions were generated with regularized Non-Negative Least Squares (NNLS)algorithm from multi-echo spin echo MRI data. From T 2 distributions, maps of seven MR parameters: N comp , T 2-short , T 2-long , geometric mean T 2 (gmT 2 ), Luminal Water Fraction (LWF), A short , and A long were generated and compared with digitized images of Hematoxylin and Eosin (H&E) stained whole-mount histology sections. Paired-t-test determined significant differences between MR parameters in malignant and non-malignant tissue. Correlation with Gleason score (GS) was evaluated with Spearman's rank correlation test. Diagnostic accuracy was evaluated using logistic generalized linear mixed effect models (GLMMs) and receiver operating characteristic (ROC) analysis. Results-The average values of four MR parameters: gmT 2 , A short , A long , and LWF were significantly different between malignant and non-malignant tissue. All MR parameters except for T 2-long showed significant correlation (P<0.05) with GS in peripheral zone (PZ). The highest correlation with GS was obtained for LWF (−0.78 ± 0.11, p < 0.001

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“…This technique has been developed based on the assumption that glandular tissue of prostate is composed of water compartments of different sizes associated with multiple T 2 relaxation times. It has been demonstrated that T 2 decay curves obtained from prostate are mainly biexponential . One may expect that the biexponential T 2 decay of prostate is composed of one term with a longer T 2 attributed to the water protons residing inside the luminal space and another term with a shorter T 2 attributed to the water protons residing within the epithelial and stromal tissue.…”

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confidence: 99%

MR measurement of luminal water in prostate gland: Quantitative correlation between MRI and histology

Sabouri

Fazli

Chang

et al. 2017

Magnetic Resonance Imaging

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Purpose-To determine the relationship between parameters measured from luminal water imaging (LWI), a new MRI T 2 mapping technique, and the corresponding tissue composition in prostate.Material and Methods-17 patients with prostate cancer were examined with a 3D multi-echo spin echo sequence at 3T prior to undergoing radical prostatectomy. Maps of seven MR parameters, called N, T 2-short , T 2-long , A short , A long , geometric mean T 2 time (gmT 2 ), and luminal water fraction (LWF), were generated using non-negative least squares (NNLS) analysis of the T 2 decay curves. MR parametric maps were correlated to digitized whole-mount histology sections. Percentage area of tissue components, including luminal space, nuclei, and cytoplasm plus stroma, was measured on the histology sections by using color-based image segmentation. Spearman's rank correlation test was used to evaluate the correlation between MR parameters and the corresponding tissue components, with particular attention paid to the correlation between LWF and percentage area of luminal space.Results-N, T 2-short , A long , gmT 2 , and LWF showed significant correlation (P<0.05) with percentage area of luminal space and stroma plus cytoplasm. T 2-short , and gmT 2 also showed significant correlation (P<0.05) with percentage area of nuclei. Overall, the strongest correlation was observed between LWF and luminal space (Spearman's coefficient of rank correlation=0.75, p < 0.001).

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Minimization of errors in biexponential T₂ measurements of the prostate

Abstract: Use of optimum echo times can substantially improve the precision of biexponential T2 measurements. This optimization is anticipated to improve prostate cancer characterization using T2 measurements.

Cited by 19 publications

References 12 publications

Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Luminal Water Imaging: A New MR Imaging T2 Mapping Technique for Prostate Cancer Diagnosis

MR measurement of luminal water in prostate gland: Quantitative correlation between MRI and histology

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Minimization of errors in biexponential T2 measurements of the prostate

Abstract: Use of optimum echo times can substantially improve the precision of biexponential T2 measurements. This optimization is anticipated to improve prostate cancer characterization using T2 measurements.

Cited by 19 publications

References 12 publications

Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Probing structure of normal and malignant prostate tissue before and after radiation therapy with luminal water fraction and diffusion‐weighted MRI

Luminal Water Imaging: A New MR Imaging T2 Mapping Technique for Prostate Cancer Diagnosis

MR measurement of luminal water in prostate gland: Quantitative correlation between MRI and histology

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Product

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Minimization of errors in biexponential T₂ measurements of the prostate