Lesion Segmentation in Dynamic Contrast Enhanced MRI of Breast

<h3>BACKGROUND AND PURPOSE:</h3> Dynamic contrast-enhanced MR imaging parameters can be biased by poor measurement of the vascular input function. We have compared the diagnostic accuracy of dynamic contrast-enhanced MR imaging...

Dynamic contrast-enhanced MR imaging parameters can be biased by poor measurement of the vascular input function. We have compared the diagnostic accuracy of dynamic contrast-enhanced MR imaging by using a phase-derived vascular input function and "bookend" T1 measurements with DSC MR imaging for preoperative grading of astrocytomas. This prospective study included 48 patients with a new pathologic diagnosis of an astrocytoma. Preoperative MR imaging was performed at 3T, which included 2 injections of 5-mL gadobutrol for dynamic contrast-enhanced and DSC MR imaging. During dynamic contrast-enhanced MR imaging, both magnitude and phase images were acquired to estimate plasma volume obtained from phase-derived vascular input function (Vp_Φ) and volume transfer constant obtained from phase-derived vascular input function (K(trans)_Φ) as well as plasma volume obtained from magnitude-derived vascular input function (Vp_SI) and volume transfer constant obtained from magnitude-derived vascular input function (K(trans)_SI). From DSC MR imaging, corrected relative CBV was computed. Four ROIs were placed over the solid part of the tumor, and the highest value among the ROIs was recorded. A Mann-Whitney U test was used to test for difference between grades. Diagnostic accuracy was assessed by using receiver operating characteristic analysis. Vp_ Φ and K(trans)_Φ values were lower for grade II compared with grade III astrocytomas (P < .05). Vp_SI and K(trans)_SI were not significantly different between grade II and grade III astrocytomas (P = .08-0.15). Relative CBV and dynamic contrast-enhanced MR imaging parameters except for K(trans)_SI were lower for grade III compared with grade IV (P ≤ .05). In differentiating low- and high-grade astrocytomas, we found no statistically significant difference in diagnostic accuracy between relative CBV and dynamic contrast-enhanced MR imaging parameters. In the preoperative grading of astrocytomas, the diagnostic accuracy of dynamic contrast-enhanced MR imaging parameters is similar to that of relative CBV.

Breast DCE-MRI segmentation for lesion detection by multi-level thresholding using student psychological based optimization

A Fuzzy C-Means (FCM)-Based Approach for Computerized Segmentation of Breast Lesions in Dynamic Contrast-Enhanced MR Images 1

How far is arterial spin labeling MRI from a clinical reality? Insights from arterial spin labeling comparative studies in Alzheimer's disease and other neurological disorders.

To test diffusion- and perfusion-weighted MR imaging techniques within the extreme time constraints of stroke evaluation before therapy, and then, with MR imaging, stratify patients into those without ischemia, those with noncortical ischemia, and those with cortical ischemia. T2-weighted turbo gradient- and spin-echo images and echo-planar diffusion- and perfusion-weighted images were obtained. Trace diffusion-weighted images and time-to-peak perfusion maps were automatically postprocessed and immediately available for interpretation. Forty-one patients with acute stroke symptoms underwent imaging within 6 hours of symptom onset; 35 were eligible for the therapy protocol. The mean time from entering the emergency department to beginning MR imaging was 45 minutes; the mean total MR imaging time was less than 15 minutes. Immediate image analysis directly affected individual clinical management. Four patients showed evidence of no infarct; seven, of lacunar infarct; and 24, of acute cortical infarct. Sixteen patients underwent angiography, thirteen had large-vessel occlusion, eleven were treated intraarterially, and in seven, recanalization was achieved. Echo-planar diffusion- and perfusion-weighted MR imaging for acute stroke is feasible and applicable before therapy decisions. Ultrafast MR imaging permitted immediate triage of 35 patients with symptoms of hyperacute stroke and thus helped avoid the risks from angiography and thrombolytic agents in some or spurred the judicious use of more aggressive intervention in others.

Introduction: Perfusion weighted imaging (PWI) increases the yield of MRI for the detection of ischemic lesions in TIA patients. We investigate whether PWI predicts the occurrence of acute diffusion weighted imaging (DWI) lesions on follow-up MRI. Methods: Consecutive patients over the age of 18 who were suspected to have a TIA were prospectively enrolled. Patients with technically adequate baseline DWI/PWI and 5 day follow-up DWI were eligible. PWI lesions were identified, blinded to clinical information, as a focal delay on MTT and/or TTP maps. Lesions were confirmed by two stroke neurologists. The baseline and follow-up MRIs were then compared to determine if a new DWI lesion had developed on follow-up and if it was located in the same brain region as the baseline PWI lesion. Results: Seventy percent (94/120) of the enrolled patients were eligible for these analyses. Mean age was 63 years (SD 13) and median ABCD 2 score was 5 (IQR 3, 5). The median delay from symptom onset to baseline MRI was 261 minutes (IQR 131-587); median delay to follow-up MRI was 5 days (IQR 3, 7). Acute ischemic lesions were present on the baseline DWI in 20 patients (21%). The baseline PWI revealed an ischemic lesion in 38 patients (41%). Acute PWI lesion were detected on both MTT and TTP maps in 34 (90%); MTT alone 2 (5%) and TTP alone 2 (5%). Combining DWI and PWI revealed an acute ischemic lesion in 42 patients (45%) distributed as follows: DWI+/PWI+ =16 (17%); DWI+/PWI- 4 (4%), DWI-/PWI+ 22 (23%), DWI-/PWI- 52 (55%). Every positive DWI lesion at baseline (n=20) continued to be DWI positive at follow up. In addition, 10 new DWI lesions were detected. Seven of these were in the same location as a positive baseline PWI lesion and 2 were both outside and inside the area of the initial perfusion deficit ; 1 was in a region that was normal at baseline. Therefore, 9/22 (41%) of the solated PWI lesions at baseline progressed to infarction. Conclusions: Early DWI lesions in patients presenting with transient neurologic symptoms were not reversible at 5 days. Early isolated PWI lesions were seen in about one fourth of these patients and nearly half progressed to infarction. These results substantiate the value of PWI for confirming the diagnosis of an ischemic lesion in patients with suspected TIA.

To assess the impact of dynamic contrast-enhanced imaging (DCE) in mp-MRI on prostate cancer (PCa) detection in a large patient cohort assigned to PI-RADS category 4. This retrospective, single center cohort study includes 193 consecutive patients with PI-RADS assessment category 4 in mp-MRI (T2WI, DWI, DCE) at 3 T with targeted plus systematic biopsy combined as the reference standard. The detection of prostate cancer with and without the use of DCE was compared. Overall, the PCa detection rate in PI-RADS-4 patients was 62 % (119/193) with DCE and 52 % (101/193) without the inclusion of lesions upgraded on the basis of DCE. 48 % (92/193) had clinically significant PCa (csPCa; Gleason score ≥ 3 + 4 = 7) and 40 % (78/193) without use of DCE. 38 of the 193 patients (20 %) had peripheral lesions upgraded from PI-RADS category 3 to an overall PI-RADS category 4 due to focal positive DCE findings. Of these 38 patients, 18 had PCa including 14 with csPCa. Thus, 15 % (18/119) of the patients with PCa and 15 % (14/92) of the patients with csPCa were detected only based on additional DCE information. DCE prevents underestimation and misclassification of a significant number of cases of peripheral csPCa and might improve detection rates in PI-RADS-4 patients. The current PI-RADS decision rules regarding upgrading PI-RADS-3 lesions to category 4 due to positive DCE imaging are useful for PCa detection. · Positive peripheral DCE upgraded 20 % of patients in PI-RADS category 4 from category 3.. · Clinically significant PCa was found in almost 40 % of upgraded, peripheral PIRADS-3-lesions.. · 15 % of all csPCa in PI-RADS-4-patients was detected in DCE-upgraded lesions.. · In 7 % of all PI-RADS-4-cases csPCa would had been underestimated without DCE upgrade.. · Ullrich T, Quentin M, Arsov C et al. Value of Dynamic Contrast-Enhanced (DCE) MR Imaging in Peripheral Lesions in PI-RADS-4 Patients. Fortschr Röntgenstr 2020; 192: 441 - 447.

Enhancement kinetics of normal ovaries on dynamic contrast-enhanced MR imaging

The Segmentation is a fundamental technique used in image processing to extract suspicious regions from a given image. Quantitative assessment of Magnetic Resonance Imaging (MRI) lesion load of patients with multiple sclerosis (MS) is the most objective approach for a better understanding of the history of the pathology, either natural or modified by therapies. Recently, numerous methods have been introduced for the segmentation of MS lesions in MR images. In this work, we propose to segment the images based on a constrained Gaussian Mixture Model (GMM) and using Genetic Algorithm to determine the optimal parameters of this highly non-linear model. We use this method for automatic segmentation of MS lesions in fluid attenuated inversion recovery (FLAIR) of magnetic resonance images. Moreover, a preprocessing step is also performed to suppress artifacts and to remove the unwanted skull portions from brain MRI. The proposed method has been tested on real patients' MR images. The experimental results show that the proposed method can effectively segment MS lesions in the brain MR images.

Automated localization of breast cancer in DCE-MRI.

To evaluate the value of dynamic contrast-enhanced MR imaging (DEMRI) and its correlation to symptoms and histopathology in chronic Achilles tendinosis. Fifteen patients with severe symptoms underwent DEMRI preoperatively and 2 years postoperatively. US-guided core biopsies of tendinosis tissue were obtained preoperatively and the specimens were analyzed using a semiquantitative protocol. DEMRI was evaluated by calculating the area under curve (AUC) of signal alteration and the static MR by a semiquantitative grading scale. A questionnaire and clinical examination evaluated the clinical outcome. Early contrast enhancement (first 72 s) was seen in DEMRI at tendon lesions of the symptomatic Achilles tendons with a significant difference to asymptomatic contralateral tendon that revealed no or mild enhancement. Increased severity of tendon pathology (including fiber structure abnormality, increased vascularity, rounding of nuclei and increased amount of glycosaminoglycans) was correlated to both dynamic and static signal enhancement. Two years following surgical treatment, the signal alterations showed regression of early contrast enhancement (AUC decreased from 9 preoperatively to 2 postoperatively). The clinical outcome was as follows: 8 patients excellent, 4 good, 2 fair and 1 poor. Patients with chronic painful achillodynia showed an early contrast-agent enhancement corresponding to the tendon lesion. Increased enhancement correlated to increased severity of tendon histopathology and patient symptoms. Two years after surgical treatment the contrast-agent enhancement decreased.

Distinguishing schwannomas from paragangliomas in the head and neck and determining succinate dehydrogenase (SDH) mutation status in paragangliomas are clinically important. We aimed to assess the clinical usefulness of DWI and dynamic contrast-enhanced MR imaging in differentiating these 2 types of tumors, as well as the SDH mutation status of paragangliomas. This retrospective study from June 2016 to June 2020 included 42 patients with 15 schwannomas and 27 paragangliomas (10 SDH mutation-positive and 17 SDH mutation-negative). ADC values, dynamic contrast-enhanced MRI parameters, and tumor imaging characteristics were compared between the 2 tumors and between the mutation statuses of paragangliomas as appropriate. Multivariate stepwise logistic regression analysis was performed to identify significant differences in these parameters. Fractional plasma volume (P ≤ .001), rate transfer constant (P = .038), time-to-maximum enhancement (P < .001), maximum signal-enhancement ratio (P < .001) and maximum concentration of contrast agent (P < .001), velocity of enhancement (P = .002), and tumor characteristics including the presence of flow voids (P = .001) and enhancement patterns (P = .027) showed significant differences between schwannomas and paragangliomas, though there was no significant difference in ADC values. In the multivariate logistic regression analysis, fractional plasma volume was identified as the most significant value for differentiation of the 2 tumor types (P = .014). ADC values were significantly higher in nonhereditary than in hereditary paragangliomas, while there was no difference in dynamic contrast-enhanced MR imaging parameters. Dynamic contrast-enhanced MR imaging parameters show promise in differentiating head and neck schwannomas and paragangliomas, while DWI can be useful in detecting SDH mutation status in paragangliomas.

To test whether parameters derived from intravoxel incoherent motion (IVIM) can be used to distinguish lung cancer from obstructive pulmonary consolidation by comparing them with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)-derived parameters and to evaluate the correlation between these quantitative parameters. A total of 31 lung cancer patients, confirmed by pathology and obstructive consolidations confirmed by positron emission tomography/computed tomography (PET-CT), were recruited. All of them were assessed with structural MRI and IVIM and 17 of them underwent additional DCE-MRI examinations. Parameters derived from IVIM and DCE-MRI in the tumour and consolidation were analysed, and the optimal cut-off values in differential diagnosis were obtained. ADC(total), D and f values were lower (P < 0.05), while IAUC60 was higher in lung cancers (P = 0.013) compared with obstructive pulmonary consolidations. According to the ROC curve, ADC(total) outperformed other perfusion and diffusion parameters with the optimal cut-off value of 1.409 × 10(-3) mm(2)/s (AUC = 0.95). Poor correlations were found between parameters derived from IVIM and DCE-MRI. IVIM-MRI is potentially useful in the differentiation of lung cancer and obstructive pulmonary consolidation. ADC(total), D and f may be reliable independent discriminating markers, but D* is variable with low diagnostic accuracy. • Lung cancer and consolidation differentiation is essential for treatment decision-making. • Perfusion and diffusion characteristics of lesions could help differential diagnosis. • IVIM can separate reflection of tissue diffusivity and microcapillary perfusion. • The relationship between perfusion quantified by IVIM and DCE-MRI is controversial.

Cyclic decapeptide CGLIIQKNEC (CLT1) has been demonstrated to target fibronectin-fibrin complexes in the extracellular matrix of different tumors and tissue lesions. Although liver fibrosis is characterized by an increased amount of extracellular matrix consisting of fibril-forming collagens and matrix glycoconjugates such as fibronectin, we aimed to investigate the feasibility of detecting and characterizing liver fibrosis using CLT1 peptide-targeted nanoglobular contrast agent (Gd-P) with dynamic contrast-enhanced magnetic resonance imaging in an experimental mouse model of liver fibrosis at 7 T. Gd-P, control peptide KAREC conjugated nanoglobular contrast agent (Gd-CP), and control nontargeting nanoglobular contrast agent (Gd-C) were synthesized. Male adult C57BL/6N mice (22-25 g; N = 54) were prepared and were divided into fibrosis (n = 36) and normal (n = 18) groups. Liver fibrosis was induced in the fibrosis group through subcutaneous injection of 1:3 mixture of carbon tetrachloride (CCl(4)) in olive oil at a dose of 4 μL/g of body weight twice a week for 8 weeks. Dynamic contrast-enhanced MRI was performed in all animals. Dynamic contrast-enhanced magnetic resonance imaging was analyzed to yield postinjection ΔR(1)(t) maps for quantitative measurements. Histological analysis was also performed. Differential enhancements were observed and characterized between the normal and fibrotic livers using Gd-P at 0.03 mmol/kg, when compared with nontargeted controls (Gd-CP and Gd-C). For Gd-P injection, both the peak and steady-state ΔR(1) of the normal livers were significantly lower than those after 4 and 8 weeks of CCl(4) dosing. Liver fibrogenesis with increased amount of fibronectin in the extracellular space in insulted livers were confirmed by histological observations. These results indicated that dynamic contrast-enhanced magnetic resonance imaging with CLT1 peptide-targeted nanoglobular contrast agent can detect and stage liver fibrosis by probing the accumulation of fibronectin in fibrotic livers.