Diffusion-weighted MRI Sequences Research Articles

Pre-excitation gradients for eddy current nulled convex optimized diffusion encoding (Pre-ENCODE).

To evaluate the use of pre-excitation gradients for eddy current-nulled convex optimized diffusion encoding (Pre-ENCODE) to mitigate eddy current-induced image distortions in diffusion-weighted MRI (DWI). DWI sequences using monopolar (MONO), ENCODE, and Pre-ENCODE were evaluated in terms of the minimum achievable echo time (TE ) and eddy current-induced image distortions using simulations, phantom experiments, and in vivo DWI in volunteers ( ). Pre-ENCODE provided a shorter TE than MONO (71.0 17.7ms vs. 77.6 22.9ms) and ENCODE (71.0 17.7ms vs. 86.2 14.2ms) in 100 of the simulated cases for a commercial 3T MRI system with b-values ranging from 500 to 3000 s/mm and in-plane spatial resolutions ranging from 1.0 to 3.0mm . Image distortion was estimated by intravoxel signal variance between diffusion encoding directions near the phantom edges and was significantly lower with Pre-ENCODE than with MONO (10.1 vs. 22.7 , ) and comparable to ENCODE (10.1 vs. 10.4 , ). In vivo measurements of apparent diffusion coefficients were similar in global brain pixels (0.37 [0.28,1.45] mm /s vs. 0.38 [0.28,1.45] mm /s, ) and increased in edge brain pixels (0.80 [0.17,1.49] mm /s vs. 0.70 [0.18,1.48] mm /s, ) for MONO compared to Pre-ENCODE. Pre-ENCODE mitigated eddy current-induced image distortions for diffusion imaging with a shorter TE than MONO and ENCODE.

Improved delineation with diffusion weighted imaging for laryngeal and hypopharyngeal tumors validated with pathology

ObjectiveThis study aims to determine the added value of a geometrically accurate diffusion-weighted (DW-) MRI sequence on the accuracy of gross tumor volume (GTV) delineations, using pathological tumor delineations as a ground truth. MethodsSixteen patients with laryngeal or hypopharyngeal carcinoma were included. After total laryngectomy, the specimen was cut into slices. Photographs of these slices were stacked to create a 3D digital specimen reconstruction, which was registered to the in vivo imaging. The pathological tumor (tumorHE) was delineated on the specimen reconstruction.Six observers delineated all tumors twice: once with only anatomical MR imaging, and once (a few weeks later) when DW sequences were also provided. The majority voting delineation of session one (GTVMRI) and session two (GTVDW-MRI), as well as the clinical target volumes (CTVs), were compared to the tumorHE. ResultsThe mean tumorHE volume was 11.1 cm3, compared to a mean GTVMRI volume of 18.5 cm3 and a mean GTVDW-MRI volume of 15.7 cm3. The median sensitivity (tumor coverage) was comparable between sessions: 0.93 (range: 0.61–0.99) for the GTVMRI and 0.91 (range: 0.53–1.00) for the GTVDW-MRI.The CTV volume also decreased when DWI was available, with a mean CTVMR of 47.1 cm3 and a mean CTVDW-MRI of 41.4 cm3. Complete tumor coverage was achieved in 15 and 14 tumors, respectively. ConclusionGTV delineations based on anatomical MR imaging tend to overestimate the tumor volume. The availability of the geometrically accurate DW sequence reduces the GTV overestimation and thereby CTV volumes, while maintaining acceptable tumor coverage.

High-resolution prostate diffusion MRI using eddy current-nulled convex optimized diffusion encoding and random matrix theory-based denoising.

To develop and evaluate a technique combining eddy current-nulled convex optimized diffusion encoding (ENCODE) with random matrix theory (RMT)-based denoising to accelerate and improve the apparent signal-to-noise ratio (aSNR) and apparent diffusion coefficient (ADC) mapping in high-resolution prostate diffusion-weighted MRI (DWI). MATERIALS ANDMETHODS: Eleven subjects with clinical suspicion of prostate cancer were scanned at 3T with high-resolution (HR) (in-plane: 1.0 × 1.0 mm2) ENCODE and standard-resolution (1.6 × 2.2 mm2) bipolar DWI sequences (both had 7 repetitions for averaging, acquisition time [TA] of 5 min 50 s). HR-ENCODE was retrospectively analyzed using three repetitions (accelerated effective TA of 2 min 30 s). The RMT-based denoising pipeline utilized complex DWI signals and Marchenko-Pastur distribution-based principal component analysis to remove additive Gaussian noise in images from multiple coils, b-values, diffusion encoding directions, and repetitions. HR-ENCODE with RMT-based denoising (HR-ENCODE-RMT) was compared with HR-ENCODE in terms of aSNR in prostate peripheral zone (PZ) and transition zone (TZ). Precision and accuracy of ADC were evaluated by the coefficient of variation (CoV) between repeated measurements and mean difference (MD) compared to the bipolar ADC reference, respectively. Differences were compared using two-sided Wilcoxon signed-rank tests (P < 0.05 considered significant). HR-ENCODE-RMT yielded 62% and 56% higher median aSNR than HR-ENCODE (b = 800 s/mm2) in PZ and TZ, respectively (P < 0.001). HR-ENCODE-RMT achieved 63% and 70% lower ADC-CoV than HR-ENCODE in PZ and TZ, respectively (P < 0.001). HR-ENCODE-RMT ADC and bipolar ADC had low MD of 22.7 × 10-6 mm2/s in PZ and low MD of 90.5 × 10-6 mm2/s in TZ. HR-ENCODE-RMT can shorten the acquisition time and improve the aSNR of high-resolution prostate DWI and achieve accurate and precise ADC measurements in the prostate.

Reproducibility and Repeatability of Intravoxel Incoherent Motion MRI Acquisition Methods in Liver.

Intravoxel incoherent motion (IVIM) diffusion weighted MRI (DWI) has potential for evaluating hepatic fibrosis but image acquisition technique influence on diffusion parameter estimation bears investigation. To minimize variability and maximize repeatably in abdominal DWI in terms of IVIM parameter estimates. Prospective test-retest and image quality comparison. Healthy volunteers (3F/7M, 29.9 ± 12.9 years) and Family Study subjects (18F/12M, 51.7 ± 16.7 years), without and with liver steatosis. Abdominal single-shot echo-planar imaging (EPI) and simultaneous multi-slice (SMS) DWI sequences with respiratory triggering (RT), breath-holding (BH), and navigator echo (NE) at 3 Tesla. SMS-BH, EPI-NE, and SMS-RT data from twice-scanned healthy volunteers were analyzed using 6 × b-values (0-800 s⋅mm-2 ) and lower (LO) and higher (HI) b-value ranges. Family Study subjects were scanned using SMS and standard EPI sequences. The biexponential IVIM model was used to estimate fast-diffusion coefficient (Df ), fraction of fast diffusion (f), and slow-diffusion coefficient (Ds ). Scan time, estimated signal-to-noise ratio (eSNR), eSNR per acquisition, and distortion ratio were compared. Coefficients of variation (CoV) and Bland Altman analyses were performed for test-retest repeatability. Interclass correlation coefficient (ICC) assessed interobserver agreement with P < 0.05 deemed significant. Within-subject CoVs among volunteers (N = 10) for f and Ds were lowest in EPI-NE-LO (11.6%) and SMS-RT-HI (11.1%). Inter-observer ICCs for f and Ds were highest for EPI-NE-LO (0.63) and SMS-RT-LO (0.76). Df could not be estimated for most subjects. Estimated eSNR (EPI = 21.9, SMS = 4.7) and eSNR time (EPI = 6.7, SMS = 16.6) were greater for SMS, with less distortion in the liver region (DR-PE: EPI = 23.6, SMS = 13.1). Simultaneous multislice acquisitions had significantly less variability and higher ICCs of Ds , higher eSNR, less distortion, and reduced scan time compared to EPI. 2 TECHNICAL EFFICACY: Stage 1.

Analysis of Diffusion-Weighted and T2-Weighted Imaging in the Prediction of Distinct Granulation Patterns of Somatotroph Adenomas

ObjectiveThe heterogeneity of the somatotroph adenomas, especially for SG and DG subtypes, has attracted great attention in identifying the imaging biomarker of them. The purpose of current study was to compare the diagnostic performance of diffusion-weighted and T2-weighted MRI sequences for preoperatively distinguishing the granulation patterns of somatotroph adenomas. Methods32 patients with clinical diagnosis of somatotroph adenomas from October 2018 to March 2023 were included in this study. Coronal diffusion-weighted imaging (DWI) and T2-weighted MRI sequences data was collected from 3.0T MRI and compared between SG and DG groups. The immunohistochemistry (IHC) was used to confirm the EM pathological subtypes and Ki67 expression levels of somatotroph adenomas postoperatively. ResultsPatients in the SG group had significantly higher signal intensity (SI) ratio of DWI (rDWI) (P<0.001), lower SI ratio of apparent diffusion coefficient (ADC) (rADC) (P<0.001), and higher SI ratio of T2-weighted imaging (rT2) (P=0.011). The combined diagnose index of rDWI and rADC had the highest diagnostic efficiency predicting SG adenomas (sensitivity, 93.3%; specificity, 88.2%; P < 0.001). The rDWI and rADC value had positive and negative correlations with Ki67 index and tumor maximum diameter, respectively. Lower rADC×103 was an independent predictor for SG adenomas. ConclusionsOur results indicated that compared with previously used T2-weighted imaging, the DWI sequence, especially the combined diagnosis index of rDWI and rADC could more efficiently distinguish the granulation patterns of somatotroph adenomas preoperatively.

Medical Radiology: Current Progress.

Recently, medical radiology has undergone significant improvements in patient management due to advancements in image acquisition by the last generation of machines, data processing, and the integration of artificial intelligence. In this way, cardiovascular imaging is one of the fastest-growing radiological subspecialties. In this study, a compressive review was focused on addressing how and why CT and MR have gained a I class indication in most cardiovascular diseases, and the potential impact of tissue and functional characterization by CT photon counting, quantitative MR mapping, and 4-D flow. Regarding rectal imaging, advances in cancer imaging using diffusion-weighted MRI sequences for identifying residual disease after neoadjuvant chemoradiotherapy and [18F] FDG PET/MRI were provided for high-resolution anatomical and functional data in oncological patients. The results present a large overview of the approach to the imaging of diffuse and focal liver diseases by US elastography, contrast-enhanced US, quantitative MRI, and CT for patient risk stratification. Italy is currently riding the wave of these improvements. The development of large networks will be crucial to create high-quality databases for patient-centered precision medicine using artificial intelligence. Dedicated radiologists with specific training and a close relationship with the referring clinicians will be essential human factors.

Role of Diffusion-Weighted MRI ( DWI) in Differentiating Between Benign and Malignant Nodules of Thyroid Taking Histopathology as Gold Standard

Background: Thyroid gland is a principal endocrine organ, first to develop in embryo, endodermal in origin and producing hormones essential for life. It is a vascular organ inclusive of right and left lobes, surrounded by a capsule and isthmus in the centre. Objective: To determine the role of Diffusion-Weighted MRI ( DWI) in differentiating between benign and malignant thyroid nodules keeping histopathology as the gold standard. Methodology: One hundred and three patients (103) were enrolled. DWI sequence was performed on 1.5 Tesla GE machine at b-values of 0, 50 and 1000 s/mm2 with correlative ADC map and quantitative values were calculated. FNAC of the thyroid nodules was carried out and results were tallied with ADC values. Out of these, five patients lost to follow up and an inadequate sample was obtained in six patients. Results: Mean age of patients (n=92) was 39 years. Out of 92 patients, 26 patients (28.3%) showed restricted diffusion on DWI in malignant thyroid nodules. Mean ADC ( Apparent Diffusion Coefficient) value of benign&#x0D; thyroid nodules (1.43 × 10-3mm2s-1) was significantly greater than malignant thyroid nodules (0.91×10-3mm s-1). For discriminating two types of nodules, cut off ADC value was determined at 1.1×10-3mm2s-1 and its sensitivity, specificity, PPV, NPV and diagnostic accuracy was 84.6, 95.4, 88.8, 91.5 and 92.3% respectively. Conclusion: Diffusion Weighted MRI is a non-invasive imaging investigation without ionizing radiation hazard. Its greater soft tissue differentiation and multiplanar images help in the diagnosis of malignant thyroid nodules with high sensitivity and accuracy. The overload of unnecessary surgeries is thus lowered when pre-operative FNAC is indecisive and aids in making a precise diagnosis.

Prospective evaluation of in vivo and phantom repeatability and reproducibility of diffusion-weighted MRI sequences on 1.5 T MRI-linear accelerator (MR-Linac) and MR simulator devices for head and neck cancers

IntroductionDiffusion-weighted imaging (DWI) on MRI-linear accelerator (MR-linac) systems can potentially be used for monitoring treatment response and adaptive radiotherapy in head and neck cancers (HNC) but requires extensive validation. We performed technical validation to compare six total DWI sequences on an MR-linac and MR simulator (MR sim) in patients, volunteers, and phantoms. MethodsTen human papillomavirus-positive oropharyngeal cancer patients and ten healthy volunteers underwent DWI on a 1.5 T MR-linac with three DWI sequences: echo planar imaging (EPI), split acquisition of fast spin echo signals (SPLICE), and turbo spin echo (TSE). Volunteers were also imaged on a 1.5 T MR sim with three sequences: EPI, BLADE (vendor tradename), and readout segmentation of long variable echo trains (RESOLVE). Participants underwent two scan sessions per device and two repeats of each sequence per session. Repeatability and reproducibility within-subject coefficient of variation (wCV) of mean ADC were calculated for tumors and lymph nodes (patients) and parotid glands (volunteers). ADC bias, repeatability/reproducibility metrics, SNR, and geometric distortion were quantified using a phantom. ResultsIn vivo repeatability/reproducibility wCV for parotids were 5.41%/6.72%, 3.83%/8.80%, 5.66%/10.03%, 3.44%/5.70%, 5.04%/5.66%, 4.23%/7.36% for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE. Repeatability/reproducibility wCV for EPIMR-linac, SPLICE, TSE were 9.64%/10.28%, 7.84%/8.96%, 7.60%/11.68% for tumors and 7.80%/9.95%, 7.23%/8.48%, 10.82%/10.44% for nodes. All sequences except TSE had phantom ADC biases within ± 0.1x10-3 mm2/s for most vials (EPIMR-linac, SPLICE, and BLADE had 2, 3, and 1 vials out of 13 with larger biases, respectively). SNR of b = 0 images was 87.3, 180.5, 161.3, 171.0, 171.9, 130.2 for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE. ConclusionMR-linac DWI sequences demonstrated near-comparable performance to MR sim sequences and warrant further clinical validation for treatment response assessment in HNC.

Monoparametric high-resolution diffusion weighted MRI as a possible first step in an MRI-directed diagnostic pathway for men with suspicion of prostate cancer.

To explore if a high-resolution diffusion weighted MRI sequence (DWI-only) could be used as a first step in an MRI-directed diagnostic pathway. Prospective single center study that between December 2017 and August 2018 included 129 consecutive patients with suspicion of prostate cancer into a PI-RADS-based MRI-directed diagnostic pathway. All patients had multiparametric MRI (mpMRI). Based on only the transversal high-resolution DWI images two consultant radiologists prospectively categorized the findings as positive, equivocal, or negative for clinically significant cancer. The radiologists then interpreted the mpMRI and assigned a PI-RADS score. A third independent reader retrospectively categorized the DWI-only exams without access to the mpMRI. The interpretations of DWI-only were compared to the PI-RADS classification from mpMRI and the histopathology from the biopsies. Non-biopsied patients were followed in a safety net monitoring for 56 months. Based on DWI-only, 29 (22.5%) of the exams were categorized as negative, 38 (29.5%) as equivocal and 62 (48.1%) as positive. Of the 56 patients with PI-RADS 4-5 at mpMRI, 55 were also categorized as positive at DWI-only. All patients diagnosed with clinically significant cancer were identified using DWI-only. 56 months of safety net monitoring did not reveal any clinically significant cancers among patients with exams categorized as negative or equivocal. There was high inter-reader agreement on positive findings, but less agreement on negative and equivocal findings. In this concept study, the monoparametric DWI-only identified all patients with clinically significant cancer in a mpMRI-directed diagnostic pathway.

Temporal and sequence-related variability in diffusion-weighted imaging of presumed cerebrovascular accidents in the dog brain.

Diffusion-weighted MRI (DWI) is often used to guide clinical interpretation of intraparenchymal brain lesions when there is suspicion for a cerebrovascular accident (CVA). Despite widespread evidence that imaging and patient parameters can influence diffusion-weighted measurements, such as apparent diffusion coefficient (ADC), there is little published data on such measurements for naturally occurring CVA in clinical cases in dogs. We describe a series of 22 presumed and confirmed spontaneous canine CVA with known time of clinical onset imaged on a single 3T magnet between 2011 and 2021. Median ADC values of < 1.0x10-3 mm2/s were seen in normal control tissues as well as within CVAs. Absolute and relative ADC values in CVAs were well-correlated (R2 = 0.82). Absolute ADC values < 1.0x10-3 mm2/s prevailed within ischemic CVAs, though there were exceptions, including some lesions of < 5 days age. Some lesions showed reduced absolute but not relative ADC values when compared to matched normal contralateral tissue. CVAs with large hemorrhagic components did not show restricted diffusion. Variation in the DWI sequence used impacted the ADC values obtained. Failure to identify a region of ADC < 1.0x10-3 mm2/s should not exclude CVA from the differential list when clinical suspicion is high.

Hippocampal dentate gyrus integrity revealed with ultrahigh resolution diffusion imaging predicts memory performance in older adults.

Medial temporal lobe (MTL) atrophy is a core feature of age-related cognitive decline and Alzheimer's disease (AD). While regional volumes and thickness are often used as a proxy for neurodegeneration, they lack the sensitivity to serve as an accurate diagnostic test and indicate advanced neurodegeneration. Here, we used a submillimeter resolution diffusion weighted MRI sequence (ZOOMit) to quantify microstructural properties of hippocampal subfields in older adults (63-98 years old) using tensor derived measures: fractional anisotropy (FA) and mean diffusivity (MD). We demonstrate that the high-resolution sequence, and not a standard resolution sequence, identifies dissociable profiles for CA1, dentate gyrus (DG), and the collateral sulcus. Using ZOOMit, we show that advanced age is associated with increased MD of the CA1 and DG as well as decreased FA of the DG. Increased MD of the DG, reflecting decreased cellular density, mediated the relationship between age and word list recall. Further, increased MD in the DG, but not DG volume, was linked to worse spatial pattern separation. Our results demonstrate that ultrahigh-resolution diffusion imaging enables the detection of microstructural differences in hippocampal subfield integrity and will lead to novel insights into the mechanisms of age-related memory loss.

Automated prediction of final infarct volume in patients with large-vessel occlusion acute ischemic stroke.

In patients with large-vessel occlusion (LVO) acute ischemic stroke (AIS), determinations of infarct size play a key role in the identification of candidates for endovascular stroke therapy (EVT). An accurate, automated method to quantify infarct at the time of presentation using widely available imaging modalities would improve screening for EVT. Here, the authors aimed to compare the performance of three measures of infarct core at presentation, including an automated method using machine learning. Patients with LVO AIS who underwent successful EVT at four comprehensive stroke centers were identified. Patients were included if they underwent concurrent noncontrast head CT (NCHCT), CT angiography (CTA), and CT perfusion (CTP) with Rapid imaging at the time of presentation, and MRI 24 to 48 hours after reperfusion. NCHCT scans were analyzed using the Alberta Stroke Program Early CT Score (ASPECTS) graded by neuroradiology or neurology expert readers. CTA source images were analyzed using a previously described machine learning model named DeepSymNet (DSN). Final infarct volume (FIV) was determined from diffusion-weighted MRI sequences using manual segmentation. The primary outcome was the performance of the three infarct core measurements (NCHCT-ASPECTS, CTA with DSN, and CTP-Rapid) to predict FIV, which was measured using area under the receiver operating characteristic (ROC) curve (AUC) analysis. Among 76 patients with LVO AIS who underwent EVT and met inclusion criteria, the median age was 67 years (IQR 54-76 years), 45% were female, and 37% were White. The median National Institutes of Health Stroke Scale score was 16 (IQR 12-22), and the median NCHCT-ASPECTS on presentation was 8 (IQR 7-8). The median time between when the patient was last known to be well and arrival was 156 minutes (IQR 73-303 minutes), and between NCHCT/CTA/CTP to groin puncture was 73 minutes (IQR 54-81 minutes). The AUC was obtained at three different cutoff points: 10 ml, 30 ml, and 50 ml FIV. At the 50-ml FIV cutoff, the AUC of ASPECTS was 0.74; of CTP core volume, 0.72; and of DSN, 0.82. Differences in AUCs for the three predictors were not significant for the three FIV cutoffs. In a cohort of patients with LVO AIS in whom reperfusion was achieved, determinations of infarct core at presentation by NCHCT-ASPECTS and a machine learning model analyzing CTA source images were equivalent to CTP in predicting FIV. These findings have suggested that the information to accurately predict infarct core in patients with LVO AIS was present in conventional imaging modalities (NCHCT and CTA) and accessible by machine learning methods.

Acute Panmyelosis with Myelofibrosis: The Serpentine Road to Diagnosis

To assess the usefulness of proton MR-spectroscopy (1H-MRS) and diffusion-weighted MRI (DW-MRI) sequences in the follow-up of CLL-patients with chemotherapy treatment.

Role of Diffusion-Weighted Magnetic Resonance Imaging inDetecting and Characterizing Benign and Malignant LiverTumors in Adults

AbstractBackground: DWI is done by quantifying the amount ofdiffusion through tissues and calculating ADC values. Tumors,which consist of excessive proliferation of cells, wouldexpectantly show restricted diffusion. ADC values can aid incharacterizing focal liver lesions as benign vs. malignant.DWI when used in combination with dynamic MRI can beused to enhance the accuracy of liver lesion characterizationand diagnosis.Aim of Study: To assess the role of diffusion-weightedmagnetic resonance imaging (DWI) in detection and charac-terization of hepatic focal lesions, and its value in differenti-ating benign from malignant masses.Patients and Methods: A total of 60 liver disease patients (21 males and 39 females) with ages ranged from 20 to 63years old were included in the study. All of the patientsunderwent MRI examination including pre-contrast imaging,dynamic study and diffusion study. The morphological featuresof each lesion were recorded and diffusion images werereviewed for final radiological characterization and detection of focal lesions. ADC values were calculated for all patients.Results: This study included 60 patients with varioustypes of lesions, 40 of which had benign lesions and 20 withmalignant lesions. The diffusion images aided in diagnosisof malignant lesions with different components. AbsoluteADC values of different types of lesions were not similar.Benign hepatic lesions have generally higher ADC valuescompared with malignant lesions. The ADC values we foundfor different lesions were consistent with previous studies.Conclusion: Diffusion-weighted MRI sequence withquantitative ADC measurement should be used as an additionalsequence to supplement conventional MRI protocol studiesfor proper detection and characterization of solid liver lesions.

The probably use of MR-spectroscopy and diffusion weighted-MRI of bone marrow for treatment monitoring in patients with chronic lymphatic leukemia

Objectives: To assess the usefulness of proton MR-spectroscopy (1H-MRS) and diffusion-weighted MRI (DW-MRI) sequences in the follow-up of CLL-patients with chemotherapy treatment. The monitoring of CLL-patients susceptible to chemotherapy treatment is complicated due to the difficulty in assessing the response to treatment. Chemotherapy leads to changes in bone marrow composition and these changes can be evaluated by functional MR-sequences. Methods: 23 patients diagnosed with CLL by our hospital’s Hematology Service underwent a lumbar MR prior and post-chemotherapy applying 1H-MRS and DW-MRI. The concentrations of water and lipids were quantified applying the quantification program LCModel. The Apparent Diffusion Coefficient (ADC) values were calculated with the Functool program (GE). The Wilcoxon sign test was used to compare pre and post treatment results, considering statistically significant P values lower than 0.05. Results: Responder patients decreased the ratio H2O/lipids concentration measured with 1H-MRS and increased the ADC value on DW-MRI in post-treatment studies (P<0.05). Patients without response increased the ratio and decreased the ADC values or did not modify the data. Conclusion: 1H-MRS and DW-MRI of spinal bone marrow are non-invasive and repeatable techniques that might help in follow-up monitoring of patients with CLL.

Diffusion-weighted MRI and FLAIR sequence for differentiation of hydatid cysts and simple cysts in the liver

PurposeThe contribution of DWI and FLAIR to the differential diagnosis of type 1, 2, and 3 hydatid cysts and simple liver cysts was investigated according to the Gharbi classification. This study is the first report using FLAIR sequence for the differential diagnosis of liver hydatid cysts in this regard. MethodsA total of 82 hydatid cysts and 40 simple cysts were scanned with DWI (in b600-b1000 values) and FLAIR sequence. In 64 patients included in the study, a total of 122 cystic lesions were diagnosed histopathologically or during follow-up. FLAIR and DWI signal characteristics were evaluated, and ADC values were calculated. ResultsThe mean ADC value of hydatid cysts on DWI (b600) was 3.07 ± 0.41 × 10−3 s/mm2, while it was 3.91 ± 0.51 × 10−3 s/mm2 for simple cysts and the difference was statistically significant (p < 0.05). On b1000 DWI, the mean ADC values of hydatid and simple cysts were 2.99 ± 0.38 × 10−3 s/mm2 and 3.43 ± 0:29 × 10−3 s/mm2, respectively (p < 0.05). The qualitative evaluation of the signal intensity on b600−1000 DWI demonstrated the difference between the simple and hydatid cyst groups (p < 0.05). Type 2 hydatid cysts alone were distinguished from type 2–3 hydatid and simple cysts by FLAIR (p < 0.05). ConclusionsADC values can distinguish between hydatid cyst and simple cyst. FLAIR contributes to the differentiation of type 2 hydatid and simple cysts.

The Value of Diffusion Weighted MRI in the Detection and Localization of Prostate Cancer among a Sample of Iraqi Patients

Background: Prostatic adenocarcinoma is the most widely recognized malignancy in men and the second cause of cancer-related mortality encountered in male patients after lung cancer.&#x0D; Aim of the study: To assess the diagnostic value of diffusion weighted imaging (DWI) and its quantitative measurement, apparent diffusion coefficient (ADC), in the identification and localization of prostatic cancer compared with T2 weighted image sequence (T2WI).&#x0D; Type of the study: a prospective analytic study&#x0D; Patients and methods: forty-one male patients with suspected prostatic cancer were examined by pelvic MRI at the MRI department of the Oncology Teaching Hospital/Medical City in Baghdad from September 2017 to September 2018. Thin sections axial T2 and DWI sequences were performed for each patient. Two patients were excluded from the study due to poor image quality (motion artefact). Regions with hypointense signal on T2WI and/or restricted lesion in DWI were determined. The ADC values were measured and the results were registered and sent for biopsy correlation. The sensitivity, specifity, accuracy and other parameters were calculated for T2WI and DWI.&#x0D; Results: The sensitivity and specifity of T2WI in the detection of prostate cancer was about 76.6% and 77% respectively. These improved to 96% and 88.8% by performing the DWI and measuring the ADC value. The mean ADC value was greatly lower in prostatic cancer (about 650x 10-6 mm2 /s) than in normal prostate parenchyma (about 1250 x10-6 mm2 /s) with significant difference between them (p value about 0.04)&#x0D; Conclusion: In practice, using diffusion weighted MRI sequence and its ADC quantitative measurement greatly increases tumor detection in patients suspicious to have prostatic cancer and should be routinely used when doing pelvic MRI for patients with high clinical suspicion.

Meningioma Detection in MR Images Using Convolutional Neural Network and Computer Vision Methods

The article discusses research efficacy of different architectures of convolutional neural network and methods of computer vision. This paper presents a novel approach to pattern detection of meningioma of the human brain in MR images. MRI images of real patients were made with a help of Samara State Medical University. The result of the research is the automatic procedure of meningioma detection. As a result, post-contrast T1 weighted MRI sequence was the most appropriate for the method based on the baseline statistical segmentation and the diffusion weighted MRI sequence was the most appropriate for the method based on the convolutional neural network.

Role of Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Hepatic Focal Lesions

Background: Diffusion-weighted imaging (DWI) is a novel imaging technique with a growing application in oncoimaging. This modality evaluates the diffusion of water molecules in various tissues, which is restricted in hypercellular regions such as malignant tissue. Apparent diffusion coefficient (ADC) is a method that can quantify the degree of restriction in tissues and can have diagnostic roles in the characterization of hepatic lesions. Aim of the Work: To study the role of diffusion-weighted MRI sequence with quantitative ADC measurements as a useful tool in the differentiation between benign and malignant liver lesions. Patients and Methods: The current study was carried out on thirty adult patients, 24 males (80%), and 6 females (20%). They were presented to Qena University Hospitals at the Radiodiagnosis Department. Results: Both, qualitative evaluation of high b-value DW-MR images and quantitative evaluation of ADC maps are employed for lesion characterization. The ADC values of benign lesions are significantly higher than those of malignant lesions, with variable degrees of overlap between the pathological entities. Conclusion: DW MR imaging has the potential to be a reasonable alternative technique to contrast-enhanced imaging.

Role of Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Hepatic Focal Lesions

Background: Diffusion-weighted imaging (DWI) is a novel imaging technique with a growing application in oncoimaging. This modality evaluates the diffusion of water molecules in various tissues, which is restricted in hypercellular regions such as malignant tissue. Apparent diffusion coefficient (ADC) is a method that can quantify the degree of restriction in tissues and can have diagnostic roles in the characterization of hepatic lesions. Aim of the Work: To study the role of diffusion-weighted MRI sequence with quantitative ADC measurements as a useful tool in the differentiation between benign and malignant liver lesions. Patients and Methods: The current study was carried out on thirty adult patients, 24 males (80%), and 6 females (20%). They were presented to Qena University Hospitals at the Radiodiagnosis Department. Results: Both, qualitative evaluation of high b-value DW-MR images and quantitative evaluation of ADC maps are employed for lesion characterization. The ADC values of benign lesions are significantly higher than those of malignant lesions, with variable degrees of overlap between the pathological entities. Conclusion: DW MR imaging has the potential to be a reasonable alternative technique to contrast-enhanced imaging.