Standard MRI Protocol Research Articles

Abstract 9607: CIED and Non-CIED MRI Imaging; Should Capped or Uncapped Abandoned Leads Remain a Contraindication?

Introduction: Infrequently, MRI is performed on patients with conventional pacemakers or ICDs. While multiple studies have documented the safety of MRI scans when performed with an approved protocol, retained leads (capped or uncapped) remain a significant concern. Hypothesis: We hypothesize that non-CIED and CIED devices in the presence of capped and uncapped leads, while inherently having no ability to for interrogation, can be performed under a similar MRI-device protocol in a safe and reliable fashion. Methods: Adapting the same MRI-device protocol as for either CIED or non-CIEDs as appropriate, tracking of patient safety to include chest pain, sustained arrhythmias or change in any device setting was performed. Results: A total of 311 pts with CIED (81%) and non-CIED (19%) from 2019-2021 at Allegheny General Hospital incorporating a total of 16 (5%) pts with retained/abandoned/fragmented leads (56% capped and 44% uncapped; p=NS) as well as 3 epicardial leads underwent MRI (GE; EXCITE, 1.5T; WI) of several regions (Brain; 72%, Ortho; 17% and CV; 11%). Repeat imaging was common (12%). Utilizing an established device protocol according to CIED or non-CIED, pts were programmed based on pt-specific pacing requirements. There were no episodes of abnormal vital signs, chest pain, sustained arrhythmias or any clinically significant device setting changes. No significant changes to impedance, amplitude, voltage or sensitivity to RA or RV/LV parameters occurred. There were no differences, naturally, between capped, uncapped or epicardial lead metrics. Likewise, no power-on resets or pacing changes were noted in the primary device system. Altogether, this supports the absence of myocardial or extra-cardiac thermal-induced injury. Infrequent, clinically insignificantly decreased RA sensing, a common natural observation in contemporary interrogation, was infrequently and transiently noted. Conclusions: Following a standard MRI protocol, according to CIED and non-CIED in pts with either capped or uncapped abandoned leads, pts suffered no ill consequences when tracked for CP, arrhythmias or device setting changes supporting a proof-of-concept notion for removing yet another obstacle for often life-changing MRI in patients with PM/ICDs.

Comparison of the Efficiency of Conventional Diffusion, Diffusion Tensor Imaging, and Dynamic Susceptibility Contrast-Enhanced Magnetic Resonance Perfusion Imaging in the Evaluation of Liver Fibrosis

Objective: Liver fibrosis is a dynamic, reversible process that can result in liver failure. There has been considerable interest in developing noninvasive methods for diagnosis and staging. To investigate the diffusion and perfusion changes of the fibrotic liver parenchyma with conventional diffusion-weighted imaging (CDI), diffusion tensor imaging (DTI), and T2*weighted dynamic susceptibility contrast-magnetic resonance perfusion imaging (DSC-MRPI) at 3Tesla MR scanner. Methods: Twenty-seven patients with chronic viral hepatitis and 24 volunteers were evaluated, prospectively. The standard MRI protocols of the abdomen, CDI, and DTI were performed. Apparent diffusion coefficient (ADC) maps were obtained, D and FA values were calculated for DTI. Signal Intensity(SI)-time curves were obtained and “blood volume”(BV), “blood flow” (BF), “time to peak”(TTP), “mean transit time”(MTT) were measured. All patients with hepatitis underwent liver biopsy. The efficacy of diffusion and perfusion parameters used in the diagnosis of fibrosis was analyzed with the receiver operating characteristic curve (ROC). Results: Patients had significantly lower liver ADC when compared to the control group, either with CDI and DTI. D values obtained from DTI were lower in patients than those of the normal volunteers, and the difference was statistically significant. On DSC-MRPI; BF, BV, MTT, and TTP of the liver were lower than those of the control group but only BV and MTT values showed statistical significance. Liver ADC, D, and BV values had a negative correlation with fibrosis. Conclusion: The results showed that the D values obtained from DTI, BV, and MTT values obtained from DSC-MRPI can be an efficient diagnostic tool for liver fibrosis in patients with chronic hepatitis.

P.048 International MAGNIMS-CMSC-NAIMS consensus recommendations on the use of standardized MRI in MS

Background: Standardized magnetic resonance imaging (MRI) guidelines published in 2015 by the Europoean MAGNIMS group and in 2016 by the CMSC are important for the diagnosis and monitoring of patients with multiple sclerosis (MS) and for the appropriate use of MRI in routine clinical practice. Methods: Two panels of experts convened to update existing guidelines for a standardized MRI protocol. The MAGNIMS panel convened in Graz, Austria in April 2019. The CMSC NAIMS panel met separately and independently in Newark, USA in October 2019. Subsequently, the MAGNIMS, NAIMS, and CMSC working groups combined their efforts to reach an international consensus Results: The revised guidelines on MRI in MS merges recommendations from MAGNIMS, CMSC, and NAIMS to improve the use of MRI for diagnosis, prognosis and monitoring of individuals with MS. 3D acquisitions are emphasized for optimal comparison over time. Core brain sequences include a 3D-T2wFLAIR for lesion identification and monitoring treatment effectiveness. Gadolinium-based contrast is recommended for diagnostic studies and judicious use for routine monitoring of MS patients. DWI sequences are recommended for PML safety monitoring. Conclusions: The international consensus guidelines strive for global acceptance of a useful and usable standard of care for patients with MS.

P-017: Repeatability and reproducibility of apparent diffusion coefficient measurements of bone marrow in magnetic resonance imaging of multiple myeloma patients

<h3>Introduciton</h3> Diffusion weighed imaging (DWI) within whole-body magnetic resonance imaging (wb-MRI) is now recommended for imaging of patients with monoclonal plasma cell disorders, and quantitative ADC measurements are of high relevance for reading and reporting of wb-MRIs. However, the evidence on repeatability and especially on multicentric reproducibility of ADC measurements of the bone marrow (BM) is very limited. The goal of this study was to quantify interrater-variability, repeatability and reproducibility of ADC measurements under variation of MRI scanners and MRI sequences. <h3>Methods</h3> Fifty-five patients were prospectively included in this IRB-approved prospective study and underwent multiple scans in different settings within a maximum of 3 days between the scans. A standard scan (clinical 1.5T-MRI scanner, standard MRI-protocol) of the pelvic bone marrow was performed. Additionally, several measurements were performed: First, a retest after new positioning of the patient (same 1.5T scanner, same protocol, i.e., repeatability; n=37 paired scans). Second, retest at the same scanner but with different MRI protocol (n=37 paired scans). Third, retest at another 1.5T scanner with a harmonized MRI protocol to the initial setting (n=34 paired scans). Fourth, retest at another scanner with different field strength of 3T (n=40 paired scans). For measurement of ADC, one radiologist manually placed regions of interest (ROI) in a representative area of BM at the posterior iliac crest and a ROI in representative muscle tissue in the same slice. A second rater independently performed a second read of the standard scan. The Bland-Altman-approach was used to assess agreement of the different settings and mean bias, limits of agreement (LoA) and coefficients of variation (CoV) were calculated. <h3>Results</h3> Absolute bias / relative bias to mean / CoV of ADC measurements for the different retest measurements compared to the standard-scan were as follows: interrater setting -37.9mm² s^-1/-0.077/15.8%, repeatability -13.0mm² s^-1/-0.027/14.5%, second protocol -205.1mm² s^-1/-0.357/33.5%, second 1.5T scanner 5.8mm² s^-1/0.013/17.0%, 3T scanner 146.8mm² s^-1/0.371/41.3%. Normalization to muscle tissue did not improve the high relative bias of the second protocol or the 3T scanner to the standard setting. <h3>Conclusion</h3> In this study we quantified interrater-variability, repeatability and reproducibility of BM ADC measurements in repeated scans after patient repositioning, different protocols, different MRI scanners and different radiologists. Bias and CoV between two different 1.5T MRI scanners with harmonized protocols were in the range of interrater-variability and repeatability. On the contrary, variation of MRI protocols and field strength of the MRI scanner led to marked bias between ADC-measurements which could not be solved by normalization to muscle tissue. These findings are of high importance for planning of multicentric imaging studies in myeloma.

Morphological evaluation of the quadriceps tendon using preoperative ultrasound in anterior cruciate ligament injured knee (114)

Morphological evaluation of the quadriceps tendon using preoperative ultrasound in anterior cruciate ligament injured knee (114)

Role of sagittal - oblique technique of MRI in diagnosis of anterior cruciate ligament injuries

Abstract Background Sagittal-oblique technique clearly shows partial rupture because its’ double angulation follows the specific course of the patient’s ligament, due to approximate orientation of the external rotation of the foot. Sagittal-oblique technique provides a higher number of slices presenting the whole course of ACL Objective To value the role of sagittal- oblique technique of MRI adding to the standardized MRI technique in the diagnosis of anterior cruciate ligament injuries. Patients and Methods The study was approved by the hospital ethical committee and all patients agreed to participate in the study. We prospectively evaluated 20 patients with MRI examination of the knee. Patients presented with painful knee joint due to trauma of knee soft tissue structures. They were 9 females and 11 males, ranging in age from 26 to 67 years. Mean age is 39.80 years. Results Accuracy of standard MRI protocol of the knee comparing to additional technique is identical in detection of a complete ACL rupture. Presentations of the partial ruptures of ACL using sagittal-oblique technique were more sensitive than presentation using standard MR protocol. There was statistically significant difference between MRI detection of the ruptured ACL between additional techniques. Sagittal-oblique technique provides a higher number of MRI slices showing the whole course of the ACL and requires a shorter scan time. Conclusion The addition of oblique sagittal technique to the standard MRI imaging improved diagnostic accuracy for detecting partial tear of the ACL. However, oblique sagittal technique is just as precise as the standard MR technique for the evaluation of a complete rupture of the ACL, so it should be used in cases of suspicion of partial rupture of the ACL

Possibilities of Diffusion-Weighted MRI in the Differential Diagnosis of Early Recurrences of Retroperitoneal Liposarcomas and Postoperative Changes

Purpose: To evaluate contrast-enhanced magnetic resonance imaging (CE‑MRI) and diffusion-weighted (DWI) in the detection and differential diagnosis of recurrent of retroperitoneal liposarcomas with postoperative changes.Material and methods: The retrospective study included of 23 patients previously operated on for retroperitoneal inorganic liposarcomas. All patients underwent MRI of the abdominal cavity and pelvis with intravenous contrast with further assessment of the size, shape, structure and characteristics of the accumulation of contrast agent in the detected formation.Results: Morphological verification were performed in 17 patients (74 %), in 6 cases (26 %) patients were left for dynamic control for 1–3 years. Local relapses were detected in 16 patients (67 %), postoperative changes — in 7 (33 %) patients, of which in 2 cases deformation of adipose tissue and fibrotic changes in the area of surgery was determined, in 3 patients granulomas were revealed, and in two patients — volvulus of the greater omentum and lymphocele. The sensitivity of MRI with intravenous contrast enhancement was 68.7 %, specificity 71.4 % and accuracy 69.6 %. The addition of DWI to the standard MRI protocol in patients with suspected recurrence of retroperitoneal liposarcoma to increase the sensitivity of the method in the differential diagnosis of recurrent drugs from postoperative changes to 93.7 % (15 out of 16), specificity up to 100 % (7 out of 7) and accuracy up to 95.6 % (22 out of 23).Conclusion: The joint use of MRI with intravenous contrast and DW‑MRI increases the information content in the detection and differential diagnosis of small-sized recurrent tumors in dedifferentiated and myxoid types of liposarcomas with postoperative changes.

A Fast Protocol for Multiparametric Characterisation of Diffusion in the Brain and Brain Tumours

Multi-parametric tissue characterisation is demonstrated using a 4-minute protocol based on diffusion trace acquisitions. Three diffusion regimes are covered simultaneously: pseudo-perfusion, Gaussian, and non-Gaussian diffusion. The clinical utility of this method for fast multi-parametric mapping for brain tumours is explored. A cohort of 17 brain tumour patients was measured on a 3T hybrid MR-PET scanner with a standard clinical MRI protocol, to which the proposed multi-parametric diffusion protocol was subsequently added. For comparison purposes, standard perfusion and a full diffusion kurtosis protocol were acquired. Simultaneous amino-acid (18F-FET) PET enabled the identification of active tumour tissue. The metrics derived from the proposed protocol included perfusion fraction, pseudo-diffusivity, apparent diffusivity, and apparent kurtosis. These metrics were compared to the corresponding metrics from the dedicated acquisitions: cerebral blood volume and flow, mean diffusivity and mean kurtosis. Simulations were carried out to assess the influence of fitting methods and noise levels on the estimation of the parameters. The diffusion and kurtosis metrics obtained from the proposed protocol show strong to very strong correlations with those derived from the conventional protocol. However, a bias towards lower values was observed. The pseudo-perfusion parameters showed very weak to weak correlations compared to their perfusion counterparts. In conclusion, we introduce a clinically applicable protocol for measuring multiple parameters and demonstrate its relevance to pathological tissue characterisation.

Diffusion-weighted MRI of solid pancreatic lesions: Comparison between reduced field-of-view and large field-of-view sequences

PurposeTo compare the image quality, presence of artifacts and apparent diffusion coefficient (ADC) values of reduced field-of-view (rFOV) and large FOV (lFOV) single-shot spin-echo echo-planar diffusion-weighted imaging (DWI) in the evaluation of solid pancreatic lesion. MethodThe 3T MR examinations of 60 patients with solid pancreatic lesions were examined. Two Readers independently performed qualitative analysis and quantitative measurements of the ADC values of the solid pancreatic lesions in both rFOV and lFOV DWI sequence. The qualitative analysis parameters included: 1) Sharpness, 2) Distortion, Ghosting, Motion and Susceptibility artifacts, 3) Lesion Conspicuity and 4) Overall Image Quality. These parameters were evaluated using a 4-point scale. The T-test for paired data was used to compare qualitative scores and the ADC values of the rFOV and lFOV DWI sequences, and to assess inter-reader agreement. ResultsThe qualitative analysis yielded scores for the rFOV DWI sequence, which were better for sharpness, artifacts, and overall image quality as compared to the lFOV DWI sequence according to the only Reader 2 (the most experienced) (p ≤ 0.001). As to lesion conspicuity, no significant difference was found by either Reader (p ≥ 0.245). As to quantitative analysis, both Readers found no significant difference between the two sequences in the ADC values of various solid pancreatic lesions (p ≥ 0.156). ConclusionsThe rFOV DWI sequence of the pancreas provides better anatomic structure visualization, reduced artifacts, and better overall image quality as compared to the lFOV DWI sequence according to the Reader with the more experience in abdominal MRI. The ADC values were not significantly different in the two sequences. The rFOV DWI sequence could be included in the standard MRI protocol for the pancreas.

Vascular dementia neurovisual markers according routine and diffusion-tensor MRI (publications’ review)

The article presents review of the most significant neurovisual biomarkers-predictors of the cognitive disfunction caused by brain vascular pathology. Also given quantitative and qualitative characteristics of this pathology including localization that can be detected using routine and diffusion-tensor MRI. Following biomarkers were noted when using standard MRI protocols: atrophy of gray matter and white matter tracts and basal nuclei; white matter hyperintensities (foci of gliosis and periventricular leukoaraiosis), micro-bleeding (large vessels, white and gray matter deposits of hemosiderin), enlarged perivascular spaces (cystic enlargement of the penetrating arteries, arterioles, veins and venules), recent small subcortical infarcts andpost-ischemic damages in cortex, basal nuclei and white matter tracts. The article outlines diffusion tensor MRI latest developments for cognitive deficits’ risk assessment, such as threshold coefficients (indexes) of the fraction anisotropy, received in neocortex tracts (frontal and temporal lobes; fronto-thalamic pathway).

Diagnostic Value of Whole-Body MRI Short Protocols in Bone Lesion Detection in Multiple Myeloma Patients.

The aim of the study is to evaluate the effectiveness of short whole-body magnetic resonance imaging (WBMRI) protocols for the overall assessment of bone marrow involvement in patients with multiple myeloma (MM), in comparison with standard whole-body MRI protocol. Patients with biopsy-proven MM, who underwent a WBMRI with full-body coverage (from vertex to feet) were retrospectively enrolled. WBMRI images were independently evaluated by two expert radiologists, in terms of infiltration patterns (normal, focal, diffuse, and combined), according to location (the whole skeleton was divided into six anatomic districts: skull, spine, sternum and ribs, upper limbs, pelvis and proximal two-thirds of the femur, remaining parts of lower limbs) and lytic lesions number (<5, 5–20, and >20). The majority of patients showed focal and combined infiltration patterns with bone lesions predominantly distributed in the spine and pelvis. As skull and lower limbs are less frequently involved by focal bone lesions, excluding them from the standard MRI protocol allows to obtain a shorter protocol, maintaining a good diagnostic value.

Added Value of MRI for Invasive Breast Cancer including the Entire Axilla for Evaluation of High-Level or Advanced Axillary Lymph Node Metastasis in the Post–ACOSOG Z0011 Trial Era

Background In the post-American College of Surgeons Oncology Group Z0011 trial era, radiologists have increasingly focused on excluding high-level or advanced axillary lymph node metastasis (ALNM) by using an additional MRI scan positioned higher than lower axillae; however, the value of these additional scans remains undetermined. Purpose To evaluate whether a standard MRI protocol is sufficient to exclude high-level or advanced ALNM in breast cancer or additional MRI of entire axilla is needed. Materials and Methods This retrospective study evaluated women with invasive breast cancer who underwent breast MRI from April 2015 to December 2016. Some underwent neoadjuvant chemotherapy (NAC) and others underwent upfront surgery. Standard (routine axial scans including the lower axillae) and combined (routine axial scans plus additional scans including the entire axilla) MRI protocols were compared for high-level or advanced ALNM detection. Clinical-pathologic characteristics were analyzed. Uni- and multivariable logistic regression was performed to identify predictors of high-level or advanced ALNM. Results A total of 435 women (mean age ± standard deviation, 52 years ± 11) were evaluated (65 in the NAC group, 370 in the non-NAC group). With the standard MRI protocol, predictors of high-level ALNM were peritumoral edema (odds ratio [OR], 12.3; 95% CI: 3.9, 39.4; P < .001) and positive axilla (OR, 5.9; 95% CI: 2.0, 15.2; P < .001). Only three of 289 women with negative axillae without peritumoral edema had high-level ALNM. Predictors of advanced ALNM were positive axillae (OR, 8.9; 95% CI: 3.7, 21.5; P < .001) and peritumoral edema (OR, 2.8; 95% CI: 1.1, 6.9; P = .03). Only six of 310 women who had negative axillae without peritumoral edema had advanced ALNM. Conclusion The performance of standard MRI was satisfactory in excluding high-level and advanced axillary lymph node metastasis in most patients with breast cancer. However, the presence of peritumoral edema or positive axillae in the MRI findings emphasizes the benefits of a combined MRI protocol. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Abe in this issue.

Coronal Gradient Echo MRI to Visualize the Zona Incerta for Deep Brain Stimulation Targeting in Parkinson’s Disease

Introduction: Deep brain stimulation of the zona incerta is effective at treating tremor and other forms of parkinsonism. However, the structure is not well visualized with standard MRI protocols making direct surgical targeting unfeasible and contributing to inconsistent clinical outcomes. In this study, we applied coronal gradient echo MRI to directly visualize the rostral zona incerta in Parkinson’s disease patients to improve targeting for deep brain stimulation. Methods: We conducted a prospective study to optimize and evaluate an MRI sequence to visualize the rostral zona incerta in patients with Parkinson’s disease (n = 31) and other movement disorders (n = 13). We performed a contrast-to-noise ratio analysis of specific regions of interest to quantitatively assess visual discrimination of relevant deep brain structures in the optimized MRI sequence. Regions of interest were independently assessed by 2 neuroradiologists, and interrater reliability was assessed. Results: Rostral zona incerta and subthalamic nucleus were well delineated in our 5.5-min MRI sequence, indicated by excellent interrater agreement between neuroradiologists for region-of-interest measurements (>0.90 intraclass coefficient). Mean contrast-to-noise ratio was high for both rostral zona incerta (6.39 ± 3.37) and subthalamic nucleus (17.27 ± 5.61) relative to adjacent white matter. There was no significant difference between mean signal intensities or contrast-to-noise ratio for Parkinson’s and non-Parkinson’s patients for either structure. Discussion/Conclusion: Our optimized coronal gradient echo MRI sequence delineates subcortical structures relevant to traditional and novel deep brain stimulation targets, including the zona incerta, with high contrast-to-noise. Future studies will prospectively apply this sequence to surgical planning and postimplantation outcomes.

Role of Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) and Apparent Diffusion Coefficient (ADC) in Evaluation of Urinary Bladder Cancer

Background: Urinary bladder cancer (BC) is reported as the 2nd most common genitourinary cancer in males and the 9th most common in females. Accurate pre-surgical evaluation of the local stage of the bladder cancer is crucial in the treatment strategy. So it is very important to evaluate and no invasive imaging modality to help accurate staging of the disease. Purpose:To evaluate role of diffusion weighted MR imaging (DW-MRI) in detection, T-staging of urinary bladder carcinoma.Patients and methods: During the period between November 2018 and November 2019, 44 patients (36 males and 8 females) presenting with haematuria, lower urinary symptoms and urinary bladder mass detected by ultrasound, were enrolled prospectively. All patients underwent standard MRI protocol and diffusion weighted MR imaging of urinary followed by transurethral cystoscopy. Then transurethral resection of the bladder tumor (TURBT) or radical cystectomy according to the tumor staging with histological examination of resected specimens. Results:Correlation between MR and cystoscopy showing 100% sensitivity in detection of the lesions and as regard to MRI staging of bladder carcinoma and histopathological results the study revealed that 38 patients (86.3%) had the same T stage while 6 patients (13.6%) were overstaged. Conclusion:DWI have very high sensitivity in detection of the bladder lesions with accurate predictions of the T staging of bladder carcinoma can be made by means of DWI.

Anterior callosal angle correlates with gait impairment and fall risk in iNPH patients.

In idiopathic normal pressure hydrocephalus (iNPH), gait and balance impairment is the most frequent symptom, and it is often associated with a higher fall risk. In a prior study, the anterior callosal angle (ACA) was validated as a reliable marker to discriminate iNPH from Alzheimer's disease and healthy controls. However, the potential correlation between the ACA with clinical symptoms and functional outcomes has not been assessed. The objective of this study is to determine the utility of the ACA in predicting gait improvement after ventriculoperitoneal (VP) shunting. Patients with probable iNPH who underwent shunt placement at a single institution were prospectively enrolled from May 2015 to May 2019. Patients were assessed preoperatively and at 6 months postoperatively following a standard clinical and MRI protocol. Callosal angle (CA) and ACA were calculated from 3T MRI preoperatively and at 6 months postoperatively. CA and ACA were tested for correlation with clinical scores. Forty-seven patients with probable INPH who completed 6-month postoperative follow-up were enrolled in the study. Baseline ACA was significantly correlated with preoperative fall risk, gait, and balance impairment assessed with Tinetti POMA scale. Additionally, baseline ACA differentiated patients who experienced improvement at Tinetti POMA scale after surgery. The baseline ACA is a useful neuroradiological marker to differentiate patients by fall risk and has significant correlation with the improvement in gait and balance impairment following surgery. This study demonstrated that the ACA may be a complementary tool to the CA in predicting shunt responsiveness in iNPH.

MRI Detection of Changes in Tissue Sodium Concentration in Brain Metastases after Stereotactic Radiosurgery: A Feasibility Study.

To date, treatment response to stereotactic radiosurgery (SRS) in brain metastases (BM) can only be determined by MRI evaluation of contrast-enhancing lesions in a long-time follow-up. Sodium MRI has been a subject of immense interest in imaging research as the measure of tissue sodium concentration (TSC) can give valuable quantitative information on cell viability. We aimed to analyze the longitudinal changes of TSC in BM measured with 23 Na MRI before and after SRS for assessment of early local tumor effects. Seven patients with a total of 12 previously untreated BM underwent SRS with 22 Gy. In addition to a standard MRI protocol including dynamic susceptibility-weighted contrast-enhanced perfusion, a 23 Na MRI was performed at three time points: (I) 2 days before, (II) 5 days, and (III) 40 days after SRS. Nine BMs were evaluated. The absolute TSC in the BM, the respective peritumoral edemas, and the normal-appearing corresponding contralateral brain area were assessed and the relative TSC were correlated to the changes in BM longest axial diameters. TSC was elevated in nine BM at baseline before SRS with a mean of 73.4±12.3 mM. A further increase in TSC was observed 5 days after SRS in all the nine BM with a mean of 86.9±13 mM. Eight of nine BM showed a mean 60.6±13.3% decrease in the longest axial diameter 40 days after SRS; at this time point, the TSC also had decreased to a mean 65.1± 7.9 mM. In contrast, one of the nine BM had a 13.4% increase in the largest axial diameter at time point III. The TSC of this BM showed a further TSC increase of 80.1 mM 40 days after SRS. Changes in TSC using 23 Na MRI shows the possible capability to detect radiobiological changes in BM after SRS.

Exploring Cortical Thickness Alteration in Parkinson Disease Patients with Freezing of Gaits

Background: Freezing of gait (FoG) is a disabling gait disorder that commonly occurs in advanced stages of Parkinson's disease (PD). The neuroanatomical mechanisms underlying FoG in PD are still unclear. The present study aims to explore alterations of structural gray matter (GM) in PD patients with FoG. Method: Twenty-four PD patients with FoG (FoG+), 37 PD patients without FoG (FoG-) and 24 healthy controls (HC) were included. All subjects underwent a standardized MRI protocol. The cortical thickness (CTh), segmentation volume without ventricles (BrainSegVolNotVent) and estimated total intracranial volume (eTIV) were analysed using the FreeSurfer pipeline. Results: CTh differences were found in the right middle temporal gyrus (rMTG) generally. Compared to that in HCs, the CTh of the rMTG in both the FoG+ and FoG- groups was smaller, while no significant difference between the FoG+ and FoG- groups. Correlation analyses demonstrated a negative correlation between the CTh of the rMTG and the UPDRS part II score in PD subjects, and a borderline significant correlation between the score of Freezing of Gait Questionnaire (FoGQ) and rMTG CTh. Additionally, receiver operating characteristic curve (ROC) analysis revealed a cut-off point of CTh =3.08 mm in the rMTG that could be used to differentiate PD patients and HCs (AUC =0.79, P <0.01). There were no differences in the BrainSegVolNotVent or eTIV among the 3 groups. Conclusions: Our findings currently suggest no significant difference between FoG+ and FoG- patients in terms of structural gray matter changes. However, decreased CTh in the rMTG related to semantic control may be used as a biomarker to differentiate PD patients and HCs.

The diagnostic performance of a simulated "short" gadoxetic acid-enhanced MRI protocol is similar to that of a conventional protocol for the detection of colorectal liver metastases.

To compare the performance of standard and simulated short gadoxetic acid-enhanced MRI protocols for the detection of colorectal liver metastases (CRLM). From 2008 to 2017, 67 patients (44 men (66%); mean age 65 ± 11 years old) who underwent gadoxetic acid-enhanced MRI during the initial work-up for colorectal cancer were included. Exams were independently reviewed by two readers blinded to clinical data in two reading sessions: (1) all acquired sequences (standard "long" protocol) and (2) only T2-weighted, diffusion-weighted, and hepatobiliary phase images (simulated "short" protocol). Readers characterized detected lesions using a 5-point scale (1-certainly benign to 5-certainly malignant). A lesion was considered a CRLM when the score was ≥ 3. The reference standard was histopathology or 12-month imaging follow-up. Chi-square, Student's t, and McNemar tests were used for comparisons. A total of 486 lesions including 331 metastases (68%) were analyzed. The metastasis detection rate was 86.1% (95% CI 82-89.4)-86.7% (82.6-90) and 85.8% (81.6-89.2)-87% (82.9-90.2) with the short and long protocols, respectively (p > 0.99). Among detected lesions, 92.1% (89.1-94.4)-94.8% (92.2-96.6) and 84.6% (80.8-87.7)-88.8% (85.4-91.5) were correctly classified with the short and long protocols, respectively (p = 0.13 and p = 0.10). The results remained unchanged when lesions scored ≥ 4 were considered as CRLM. The diagnostic performance of a simulated short gadoxetic enhanced-MR protocol including T2-weighted, diffusion-weighted, and hepatobiliary phase appears similar to that of a standard long protocol including dynamic phase images. Since this protocol shortens the duration of MR examination, it could facilitate the evaluation of patients with colorectal liver metastases. • The detection rate of colorectal metastases with a simulated, short, MRI protocol was similar to that of a standard protocol. • The performance of both protocols for the differentiation of metastases and benign lesions appears to be similar. • A short MR imaging protocol could facilitate the evaluation of patients with colorectal liver metastases.

Differences in Advanced Magnetic Resonance Imaging in MOG-IgG and AQP4-IgG Seropositive Neuromyelitis Optica Spectrum Disorders: A Comparative Study.

Aims: To explore differences in advanced brain magnetic resonance imaging (MRI) characteristics between myelin oligodendrocyte (MOG) immunoglobulin (IgG) and aquaporin-4 (AQP4) IgG seropositive (+) neuromyelitis optica spectrum disorders (NMOSD).Methods: 33 AQP4-IgG and 18 MOG-IgG seropositive NMOSD patients and 61 healthy control (HC) subjects were included. All 112 participants were scanned with the same standardized MRI-protocol on a 3-Tesla MRI-scanner. Brain volume and diffusion tensor imaging (DTI) parameters were assessed.Results: MOG-IgG+ patients showed reduced parallel diffusivity within white matter tracts compared to HC whereas AQP4-IgG+ showed no significant brain parenchymal damage in DTI analysis. AQP4-IgG+ patients showed reduced whole brain volumes and reduced volumes of several deep gray matter structures compared to HC whereas MOG-IgG+ patients did not show reduced brain or deep gray matter volumes compared to HC.Conclusions: Microstructural brain parenchymal damage in MOG-IgG+ patients was more pronounced than in AQP4-IgG+ patients, compared with HC, whereas normalized brain volume reduction was more severe in AQP4-IgG+ patients. Longitudinal imaging studies are warranted to further investigate this trend in NMOSD. Our results suggest that MOG-IgG+ and AQP4-IgG+ NMOSD patients differ in cerebral MRI characteristics. Advanced MRI analysis did not help to differentiate between MOG-IgG+ and AQP4-IgG+ patients in our study.

Additional Anterior Cruciate Ligament MRI Examination Protocols: a Standard of Diagnosis or a Whim of Researchers? (Review)

Summary. Standard MRI protocols of the knee joint in case of suspected anterior cruciate ligament (ACL) injury involve tomography in three mutually perpendicular planes – coronal, sagittal, and axial. Modern methods of treatment (especially refixation of the ACL and reconstruction of separate ACL bundles) and rehabilitation require more accurate diagnosis not only of the fact of injury, but also its clear location, degree and term. It is especially difficult to assess the nature and extent of ACL damage in the acute period and in cases of partial injury. Therefore, we propose to introduce into the standard of ACL MRI examination the additional use of oblique sagittal and oblique coronal sequences (images) oriented at an angle of ACL fibers with reduced to 0-2 mm interslice interval to improve the diagnosis of ACL injury. To reduce the duration of the study, it is possible to limit yourself to a small number of slices (images) in additional projections only in the area of the ACL.