Diffusion-weighted Imaging Findings Research Articles

Diffusion-weighted imaging as a potential non-gadolinium alternative for immediate assessing the hyperacute outcome of MRgFUS ablation for uterine fibroids.

The aim of this study was to investigate the value of diffusion-weighted imaging (DWI) as a potential non-gadolinium alternative for promptly assessing the hyperacute outcome of magnetic resonance-guided focused ultrasound (MRgFUS) treatment for uterine fibroids. In this retrospective study we included 65 uterine fibroids from 44 women, who underwent axial DWI (b-value: 800s/mm2) and contrast-enhanced (CE) MR within 15min post-ablation. Two blinded observers independently reviewed the DWI findings of ablated necrotic lesions and measured their volumes on DWI and CE images. The post-ablation DWI images revealed clear depiction of ablative necrotic lesions in all fibroids, which were classified into two types: the bull's eye sign (type 1) and the bright patch sign (type 2). The inter-observer intraclass correlation coefficient for classifying DWI signal types was 0.804 (p < 0.001). Volumetric analysis of ablated necrosis using DWI and CE T1-weighted imaging showed no significant variance, nor did the non-perfused volume ratios (all p > 0.05). Bland-Altman analysis revealed a mean difference of 2.38% and 1.71% in non-perfused volume ratios between DWI and CE, with 95% limits of agreement from - 19.06 to 23.82% and - 18.40 to 21.82%, respectively. The findings of this study support the potential of DWI as a viable non-gadolinium alternative for evaluating the hyperacute outcomes of MRgFUS ablation in uterine fibroids.

Atypical Diffusion-weighted Imaging Findings in a Patient with Occipital Lobe Seizures (P5-1.007)

Atypical Diffusion-weighted Imaging Findings in a Patient with Occipital Lobe Seizures (P5-1.007)

Acute Magnetic Resonance Imaging Findings in Young Children With Moyamoya Disease

BackgroundTo describe the diffusion-weighted imaging (DWI) findings in young children with moyamoya disease (MMD) during the acute period of the condition. MethodsClinical data were collected from 12 children with MMD aged less than six years, in whom abnormalities were observed on DWI scans obtained within one week after the appearance of symptoms related to MMD. The DWI abnormalities were classified into gyral, atypical territorial, honeycomb, classical territorial, multiple-dot, border zone, and deep lacunar patterns. The severity of arterial stenosis was graded by angiographic stages that have been previously described. ResultsIn all but one child, the DWI abnormalities were restricted to the cerebral cortex. The lesions were gyral in nature in seven children and atypical territorial in five; all differed from those of typical arterial strokes. Internal carotid artery stenosis was observed in all 12 children, although the stenosis was mild in 11. The severity of arterial stenosis did not match the regions of ischemic lesions in some children. There was no statistically significant difference in the severity of arterial stenosis according to the presence or absence of ischemic lesions or the pattern of the lesions. ConclusionsLesions located mainly in the cerebral cortex, i.e., not in arterial territories, are characteristic of young children with MMD.

Transradial versus transfemoral access for diagnostic cerebral angiography: frequency of acute MRI findings in 500 consecutive patients at a single center

BackgroundThe frequency of clinically symptomatic and asymptomatic diffusion-weighted imaging (DWI) hyperintense lesions and their correlation with the transradial artery (TRA) approach is unclear.ObjectiveTo assess the frequency of abnormal diffusion restriction...

Comparison of Early Postoperative Diffusion Weighted Magnetic Resonance Imaging Findings After Resection of Gliomas and Meningiomas

Glioma and meningioma require vastly different surgical approaches, even if only involving a simple craniotomy procedure. Diffusion weighted imaging (DWI) is useful for the postoperative evaluation of ischemic damage. The present study evaluated the expected but unproven differences in DWI findings. A total of 41 patients with meningiomas and 63 with gliomas met the inclusion criteria for adult cases with superficial lesions treated through simple supratentorial craniotomy. Postoperative DWI findings of DWI-positive rate, DWI-positive area type, and relationship with neurological deficits were evaluated. The DWI-positive rate (P=0.01) and the proportion of rim-type lesions (P<0.01) were significantly more common in gliomas. Patients with meningiomas and DWI-positive areas presented with higher rates of new neurological deficits (P<0.01), and patients with meningiomas on the left side were more likely to develop new neurological deficits (P=0.02). Patients with gliomas tended to develop new deficits with larger DWI-positive area volumes (P=0.04). Postoperative early DWI-positive rate and rim-type lesions are more common after glioma resection than meningioma resection. Larger volumes of DWI-positive areas may be associated with postoperative neurological symptoms in gliomas. DWI-positive finding is less common after meningioma than glioma resection but more likely to be associated with new neurological symptoms. These differences are important for adequate postoperative DWI evaluation of common supratentorial brain tumors.

Predicting the Consistency of Pituitary Macroadenomas: The Utility of Diffusion-Weighted Imaging and Apparent Diffusion Coefficient Measurements for Surgical Planning.

Understanding the consistency of pituitary macroadenomas is crucial for neurosurgeons planning surgery. This retrospective study aimed to evaluate the utility of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) as non-invasive imaging modalities for predicting the consistency of pituitary macroadenomas. This could contribute to appropriate surgical planning and therefore reduce the likelihood of incomplete resections. The study included 45 patients with pathologically confirmed pituitary macroadenomas. Conventional MRI sequences, DWIs, ADC maps, and pre- and post-contrast MRIs were performed. Two neuroradiologists assessed all of the images. Neurosurgeons assessed the consistency of the tumor macroscopically, and histopathologists examined it microscopically. The MRI findings were compared with postoperative data. According to the operative data, macroadenomas were divided into the two following categories based on their consistency: aspirable (n = 27) and non-aspirable tumors (n = 18). A statistically significant difference in DWI findings was found when comparing macroadenomas of different consistencies (p < 0.001). Most aspirable macroadenomas (66.7%) were hyperintense according to DWI and hypointense on ADC maps, whereas most non-aspirable macroadenomas (83.3%) were hypointense for DWI and hyperintense on ADC maps. At a cut-off value of 0.63 × 10-3 mm2/s, the ADC showed a sensitivity of 85.7% and a specificity of 75% for the detection of non-aspirable macroadenomas (AUC, 0.946). The study concluded that DWI should be routinely performed in conjunction with ADC measurements in the preoperative evaluation of pituitary macroadenomas. This approach may aid in surgical planning, ensure that appropriate techniques are utilized, and reduce the risk of incomplete resection.

Prediction of underweight, short stature, and microcephaly based on brain diffusion-weighted imaging sequence in neonates with stage.2 of hypoxic-ischemic encephalopathy: A follow-up study.

Hypoxic-ischemic encephalopathy (HIE), caused due to reduced oxygenation and brain blood flow, occurs in 1-8 per 1000 live full-term births in developed countries and up to 26 per 1000 live in the developing world. The growth status of survivors of birth HIE has not been evaluated sufficiently. This study evaluated, the growth parameters (weight, height, and head circumference) of neonates with Sarnat stage.2 of HIE at 6, 10, and 12 months and its relationship with findings of neonatal brain diffusion-weighted imaging (DWI) sequence. Medical records and growth parameters of 35 neonates with gestational age 34 wk who were admitted with stage.2 of HIE in Neonatal Intensive Care Unit of Shahid Sadoughi hospital, Yazd, Iran from March 2021-March 2022, and its relationship with neonatal brain DWI sequence finding was evaluated. 15 girls and 20 boys with a mean birth weight of 2880.3 221.8 gr were evaluated. Conventional magnetic resonance imaging and DWI were found to be abnormal in 6 (17.1%) and 18 neonates (51.4%). The most abnormal finding of DWI was high signal in basal ganglia/thalamus in 9 neonates (25.7%). Abnormal DWI is more frequent in neonates with seizures and low birth weight. Hospital stay days were more prolonged in neonates with abnormal DWI. Microcephaly at 12 months was more frequent in children with abnormal DWI. In survivors of moderate neonatal HIE, abnormal brain DWI sequence might predict inappropriate head growth, and need close medical and nutritional interventions for growth improvement.

Diagnostic MR imaging features of hypomyelination of early myelinating structures: A case report.

Hypomyelination of early myelinating structures (HEMS) has recently been defined as a new genetic disorder accompanied by clinical and MR imaging characteristics. However, no studies have focused on diffusion-weighted imaging (DWI) findings of HEMS. We would like to propose a "sheep sign," which is formed by DWI hyperintensity in the medial medullary lamina along with alternating high-low-high (HLH) intensity stripes in the posterior limb of the internal capsule. We believe the presence of the "sheep sign" on DWI in combination with alternating HLH intensity stripes may be a valuable tool for diagnosing HEMS.

Preoperative Dynamic Contrast-Enhanced and Diffusion-Weighted Breast Magnetic Resonance Imaging Findings for Prediction of Lymphovascular Invasion of the Lesions in Node-Negative Invasive Breast Cancer.

Purpose: Our single-centre retrospective study aimed to investigate the relationship between preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) findings and apparent diffusion coefficient (ADC) values and lymphovascular invasion (LVI) status of the lesions in patients with clinically-radiologically lymph node-negative invasive breast cancer. Methods: A total of 250 breast lesions diagnosed in preoperative magnetic resonance imaging were identified. All patients were divided into 2 subgroups: LVI-negative and LVI-positive according to the pathological findings of surgical specimens. The 2 groups' DCE-MRI findings, ADC values, and histopathological results of lesions were compared. Results: LVI was detected in 100 of 250 lesions. Younger age than 45 years and larger lesion size than 20 mm were found to be associated with the presence of LVI (P < .001). High histological and nuclear grade (P = .001), HER2-enriched molecular subtype (P = .001), and Ki-67 positivity (P = .016) were significantly associated with LVI. The LVI positivity rate was significantly higher in the lesions with medium-rapid initial phase kinetic curve and washout delayed phase kinetic curve (P = .001). The presence of LVI was significantly associated with the presence of peritumoural edema, sentinel lymph node metastasis, adjacent vessel sign, and increased whole breast vascularity (P < .001). When diffusion-weighted imaging findings were evaluated, it was determined that tumoural ADC values lower than 1068 × 10-6 mm2/second (P = .002) and peritumoural-tumoural ADC ratios higher than 1.5 (P = .001) statistically increased the probability of LVI. Conclusion: The patient's age, various histopathological and DCE-MRI findings, tumoural ADC value, and peritumoural-tumoural ADC ratio may be useful in the preoperative prediction of LVI status in breast cancer lesions.

Diffusion-Weighted MR Imaging of the Thymus in Children with Non-Thymic Neoplasms.

Purpose: To investigate the diffusion-weighted imaging (DWI) findings and apparent diffusion coefficient (ADC) value of the thymus in children under the age of 13 who have non-thymic neoplasms. Materials and Methods: From January 2021 to April 2023, a single-center retrospective study analyzed consecutive 191 thoracic MRI scans with DWI from 67 children (<13 years) with non-thymic neoplasms. The scans were categorized based on the presence of restricted diffusion on DWI. We analyzed the demographics, laboratory data, and MR findings of the thymus. Statistical differences were assessed using generalized estimating equations. Results: Forty-five percent (86/191) of the scans exhibited restricted diffusion in the thymus: multifocal (n = 65; 76%), focal (n = 19; 22%), and diffuse (n = 2; 2%) patterns. The restricted diffusion group demonstrated higher absolute lymphocyte counts, more prominent thymus sizes, and higher frequency of off-treatment status compared to the unrestricted diffusion group (p>0.05). The mean ADC value across all 191 scans was 1.80 × 10-3 mm2/s. No significant difference was observed in the ADC value related to restricted diffusion patterns, the MRI vendors, or the age at the time of the scan. Conclusions: Restricted diffusion was observed in 45% of the thymus in children with non-thymic neoplasms, with a mean ADC value of 1.80 × 10-3 mm2/s. Recognizing the DWI findings can prevent unnecessary invasive procedures, alleviating concerns for patients and families.

Abstract 296: Comparison of Prognostic Performance Using Quantitative Analysis of Head Computed Tomography and Apparent Diffusion Coefficient Imaging Before Target Temperature Management in Out-of-Hospital Cardiac Arrest Survivors

Aim: We compared head computed tomography (HCT) and diffusion-weighted magnetic resonance imaging (DW-MRI) findings before target temperature management (TTM) to predict neurological outcomes in out-of-hospital cardiac arrest survivors. Methods: Using prospectively collected data from a TTM registry, we included patients who underwent HCT and DW-MRI within 6 h of return of spontaneous circulation (ROSC). We examined the gray-to-white matter ratio (GWR) on HCT and apparent diffusion coefficient (ADC) values obtained through voxel-based analysis of DW-MRI. We analyzed the mean ADC value and the % voxels of ADC thresholds (percentage of voxels below ADC thresholds per total voxel) at 50-step intervals ranging from 200 to 1200 х 10 -6 mm/s, identifying thresholds that differentiate between good and poor neurological outcomes. Additionally, we analyzed the combination of pupillary light reflex (PLR) and neuron-specific enolase (NSE) values acquired at the same time points to predict the neurological outcomes. The primary outcome measure was the dichotomized cerebral performance category (CPC) at six months, defined as good (CPC 1-2) or poor (CPC 3-5). Results: Of 131 patients (26% female), 74 (57%) had poor outcomes. The time from ROSC to HCT and DW-MRI scans was 1.7h and 3.2h, respectively. The group with a good outcome had higher GWR (1.26 vs. 1.20) and mean ADC (787.10 vs. 697.49) values, but lower values in all ranges (250-1150) of ADC values (all P&lt;0.001). Mean ADC and ADC values in the range of 350-650 demonstrated better predictive performance for poor outcomes than the GWR (P &lt; 0.05). The mean ADC value had the highest sensitivity of 51.3% (95% CI 39.4-63.1; cutoff value ≤ 739.2 х 10 –6 mm 2 /s) when the false positive rate (FPR) was 0%. Furthermore, when combined with PLR and NSE values, the prognostic performance was significantly improved compared to using Mean ADC alone (0.83 vs 0.92; P&lt;0.01). Conclusions: In this cohort study, early voxel-based quantitative ADC analysis after ROSC (i.e., before TTM) was associated with poor neurological outcomes 6 months after cardiac arrest. We found that the Mean ADC value showed the highest sensitivity when the FPR was 0% and that combining the NSE and PLR values resulted in an even better prognostic performance.

Quantitative analysis of early apparent diffusion coefficient values from MRIs for predicting neurological prognosis in survivors of out-of-hospital cardiac arrest: an observational study

BackgroundThis study aimed to quantitatively analyse ultra-early brain diffusion-weighted magnetic resonance imaging (DW-MRI) findings to determine the apparent diffusion coefficient (ADC) threshold associated with neurological outcomes in comatose survivors of out-of-hospital cardiac arrest (OHCA).MethodsThis retrospective study included adult survivors of comatose OHCA who underwent DW-MRI imaging scans using a 3-T MRI scanner within 6 h of the return of spontaneous circulation (ROSC). We investigated the association between neurological outcomes and ADC values obtained through voxel-based analysis on DW-MRI. Additionally, we constructed multivariable logistic regression models with pupillary light reflex (PLR), serum neuron-specific enolase (NSE), and ADC values as independent variables to predict poor neurological outcomes. The primary outcome was poor neurological outcome 6 months after ROSC, determined by the Cerebral Performance Category 3–5.ResultsOverall, 131 patients (26% female) were analysed, of whom 74 (57%) showed poor neurological outcomes. The group with a poor neurological outcome had lower mean whole brain ADC values (739.1 vs. 787.1 × 10–6 mm/s) and higher percentages of voxels with ADC below threshold in all ranges (250–1150) (all P < 0.001). The mean whole brain ADC values (area under the receiver operating characteristic curve [AUC] 0.83) and the percentage of voxels with ADC below 600 (AUC 0.81) had the highest sensitivity of 51% (95% confidence interval [CI] 39.4–63.1; cut-off value ≤ 739.2 × 10−6 mm2/s and > 17.2%, respectively) when the false positive rate (FPR) was 0%. In the multivariable model, which also included PLR, NSE, and mean whole brain ADC values, poor neurological outcome was predicted with the highest accuracy (AUC 0.91; 51% sensitivity). This model showed more accurate prediction and sensitivity at an FPR of 0% than did the combination of PLR and NSE (AUC 0.86; 30% sensitivity; P = 0.03).ConclusionsIn this cohort study, early voxel-based quantitative ADC analysis after ROSC was associated with poor neurological outcomes 6 months after cardiac arrest. The mean whole brain ADC value demonstrated the highest sensitivity when the FPR was 0%, and including it in the multivariable model improved the prediction of poor neurological outcomes.

Magnetic resonance imaging features of presumed intracerebral hemorrhages in dogs show a significant association between apparent diffusion coefficient peripheral layer and estimated bleeding age and commonly exhibit a T2 blackout effect.

In humans, intracranial hematomas commonly exhibit a T2 blackout effect (BOE) with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps. Published descriptions of comparable findings in dogs with intracerebral hemorrhages are lacking. Aims of this retrospective observational study were to describe the appearance of presumed intracerebral hemorrhages (PICHs) in DWI regardless of the underlying etiology and presence of T2 blackout effect (T2 BOE) in dogs and to test potential associations with DWI and ADC findings versus the estimated age of the hemorrhage. Magnetic resonance imagingstudies of dogs with presumed PICHs based on the combined evaluation of T2*W gradient echo and/or susceptibility-weighted imaging, T1W and T2W images were enrolled. The age of the hemorrhage was estimated according to published criteria based on T1W and T2W sequences. The association between the age of the hemorrhage and the appearance of each finding (stratified or mixed), their signal intensities in DWI/ADC and the presence of the T2 BOE, was evaluated. A total of 35 PICHs were included: 13 of them were stratified and 22 had a mixed aspect. Only the ADC appearance of the peripheral layer in stratified PICHs was significantly associated with estimated age of the hemorrhage (p=.033), being hypointense in all hyperacute cases and hypo-/isointense in acute cases. The T2 BOE was present in 29/35 PICHs. The DWI sequences showed limited utility to date PICHs in this study population. As in humans, the T2 BOE was commonly seen in DWI and ADC maps of dogs with PICHs.

The dynamic contrast enhanced-magnetic resonance imaging and diffusion-weighted imaging features of alveolar soft part sarcoma.

Alveolar soft part sarcoma (ASPS) is a rare type of soft tissue sarcoma that predominantly affects adolescents and young adults. Early diagnosis of ASPS is crucial for optimal therapeutic planning and improving prognosis, but its diagnostic features are not well delineated. This study aimed to retrospectively analyze the imaging features of ASPS with an emphasis on the dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) findings to identify imaging findings that might suggest the diagnosis to radiologists. The imaging features of 34 patients with pathologically proven limb ASPS were retrospectively analyzed. A total of 23 underwent DCE-MRI, and 12 underwent DWI. Among the 34 cases of ASPS, 31 tumors were in the lower extremities, and 3 were in the upper extremities. The maximum tumor diameters ranged from 3.0 to 19.4 cm (mean, 8.7±3.96 cm). A total of 28 cases had well-defined borders. The masses demonstrated heterogeneous high signal intensity on T2-weighted imaging (T2WI) and the fat-suppressed (FS) T2WI sequence and slight hyperintensity on T1-weighted imaging (T1WI). A total of 25 lesions had thin hypointense bands on T1WI and T2WI. Intra- and peri-tumoral tubular areas of flow void were exhibited on both T1WI and T2WI in all cases. A total of 12 cases showed a high signal on DWI, and the mean apparent diffusion coefficient (ADC) value was (0.86±0.07)×10-3 mm2/s [range, (0.6-1.4)×10-3 mm2/s]. Persistent remarkable enhancement of the lesion was displayed on contrast-enhanced scans. The time-intensity curves (TICs) of 23 masses showed early arterial enhancement and slow washout of contrast. ASPS most commonly presents in the lower extremities of adolescents or young adults. Hyperintense T1WI, T2WI, and DWI signals, low ADC, flow voids, early arterial enhancement are frequent MRI features.

Dynamic susceptibility contrast perfusion-weighted and diffusion-weighted magnetic resonance imaging findings in pilocytic astrocytoma and H3.3 and H3.1 variant diffuse midline glioma, H3K27-altered.

This study compared the dynamic susceptibility contrast (DSC) magnetic resonance imaging parameters and apparent diffusion coefficient (ADC) between pilocytic astrocytoma (PA) and diffuse midline glioma, H3K27-altered (DMG) variants. The normalized relative cerebral blood volume (nrCBV), normalized relative flow (nrCBF), percentile signal recovery (PSR), and normalized mean ADC (nADCmean) of 23 patients with midline PAs (median age, 13 years [range, 1-71 years]; 13 female patients) and 40 patients with DMG (8.5 years [1-35 years]; 19 female patients), including 35 patients with H3.3- and five patients with H3.1-mutant tumors, treated between January 2016 and May 2022 were statistically compared. DMG had a significantly lower nADCmean (median: 1.48 vs. 1.96; p = 0.00075) and lower PSR (0.97 vs. 1.23, p = 0.13) but higher nrCBV and nrCBF (1.66 vs. 1.17, p = 0.058, respectively, and 1.87 vs. 1.19, p = 0.028, respectively) than PA. The H3.3 variant had a lower nADCmean than the H3.1 variant (1.46 vs. 1.80, p = 0.10). DMG had lower ADC and PSR and higher rCBV and rCBF than PA. The H3.3 variant had a lower ADC than the H3.1 variant. Recognizing the differences and similarities in the DSC parameters and ADC between these tumors may help presurgical diagnosis.

Role of Multiparametric Magnetic Resonance Imaging of the Brain in Differentiating Neurocysticercosis From Tuberculoma.

The two most common infectious causes of ring-enhancing lesions are neurocysticercosis (NCC) and tuberculoma. It is a challenge to differentiate NCC and tuberculomas radiologically since they show the same imaging findings on computed tomography (CT). Hence, this study was performed to assess the role of magnetic resonance imaging (MRI) as an additional advanced modality to aptly characterize the lesion. Conventional MRI with additional advanced imaging sequences like diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), magnetic resonance spectroscopy (MRS), and post-contrast T1-weighted imaging (T1WI) aids in characterizing the lesion and helps in differentiating NCC and tuberculomas. To compare the findings of DWI, ADC cut-off values, spectroscopy, and contrast-enhanced MRI in differentiating NCC from tuberculoma. Individuals who matched the inclusion criterion underwent an MRIof the brain (plain and contrast) in a 1.5 Tesla, 18-channel, magnetic resonance scanner (Magnetom Avanto®, Siemens Healthineers, Erlangen, Germany). The following imaging sequences were included: T1WI (axial and sagittal), T2-weighted imaging (axial and coronal), fluid-attenuated inversion recovery, DWI at 0, 500, and 1000 mm2/sb-values with corresponding ADC values, and single-voxel MRS. Based on MRI features such as number, size, location, margins of lesions, scolex, surrounding edema, DWI features with corresponding ADC values, enhancement pattern of lesions, and spectroscopy findings, we evaluated and differentiated the lesions as NCC or tuberculoma. Radiological diagnoses were correlated in terms of clinical symptoms and response to treatment. In our study, 42 subjects were included, of which the total number of NCC cases was 25 (59.52%) and tuberculoma was 17 (40.47%). The mean age of patients included was 42.85 ± 14.76 years (21 to 78 years). On post-contrast imaging, all 25 cases of NCC (100%) showed thin ring enhancement whereas the majority of tuberculomas (64.7%) showed thick irregular ring enhancement. On MRS, all 25 cases (100%) of NCC showed an amino acid peak and all 17 cases (100%) of tuberculoma showed a lipid lactate peak. On DWI, out of 25 NCC cases, restriction of diffusion was absent in the majority of cases (88%) and out of 17 cases of tuberculoma, restriction of diffusion was present in 12 cases (70.5%) (T2 hyperintense tuberculoma, indicative of caseating tuberculoma with central liquefaction) and was absent in the rest. In our study, the mean ADC value of NCC lesions (1.30 ± 0.137 x 10-3 mm2/s) was found to be greater than that of tuberculoma (0.74 ± 0.090 x 10-3 mm2/s). ADC value of 1.2 x 10-3 was obtained as a cut-off to differentiate NCC and tuberculoma. The ADC cut-off value of 1.2 x 10-3 mm2/s showed a sensitivity of 92% and specificity of 94.1% in differentiating NCC from tuberculoma. Conventional MRI with additional advanced imaging sequences likeDWI, ADC, MRS, and post-contrast T1WI aids in characterizing the lesion and thereby helps in differentiating NCC and tuberculomas. Hence, multiparametric MRI assessment is useful in making a prompt diagnosis and eliminating the need for a biopsy.

Silent Micro-Infarct in Carotid Artery Stenting: Who Has it and Why?

Carotid stenosis (CS) is one of the modifiable risk factors for stroke. We aimed to compare the postprocedural cerebral diffusion-weighted imaging (DWI) findings in cases of CS-related carotid plaques in terms of plaque morphology, degree of stenosis, and the use of a distal protection filter. We also used DWI to assess the asymptomatic cerebral embolism rates during carotid artery stending (CAS) operations performed for noncalcified versus calcified carotid plaques. Our study included 99 patients admitted to the Ankara City Hospital Stroke Center in 2022. All of our patients have been evaluated and scheduled for CAS as a result of a decision made by the council. Cases of stenosis of 50% in symptomatic patients and 70% in asymptomatic patients were included. The patients were grouped according to their Doppler ultrasonography results. All of the patients underwent DWI within the first 24 hours after the procedure, and then two groups of patients were compared. A statistically significant difference was found between the distributions of the presence of silent micro-infarcts on DWI in terms of plaque characteristics (p 0.001). In the patients with normal DWI findings, the percentage of calcified plaques was 38.7%, while the percentages of hypoechoic plaques, plaques with low echogenicity, and ulcerated plaques were 91.3%, 85.7%, and 78.8%, respectively. The rates of calcified plaques and ulcerated plaques differed in the group of patients with silent micro-infarcts. The rate of silent micro-infarcts was 61.3% in the patients with calcified plaques, 8.7% in those with hypoechoic plaques, 14.3% in those with low-echogenicity plaques, and 21.2% in those with ulcerated plaques. The study found that carotid stents implanted in calcified and ulcerated plaques had a higher correlation with the presence of periprocedural asymptomatic ipsilateral DWI findings than those implanted in hypoechoic plaques and low-echogenicity plaques.

Intravoxel Incoherent Motion Diffusion-Weighted MR Imaging Findings of Infrapatellar Fat Pad Signal Abnormalities: Comparison Between Symptomatic and Asymptomatic Knee Osteoarthritis

Infrapatellar fat pad (IPFP) proton density-weighted images (PdWI) hyperintense regions on MRI are an important imaging feature of knee osteoarthritis (KOA) and are thought to represent inflammation which may induce knee pain. The aim of the study was to compare the intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) findings of PdWI hyperintense regions of IPFP between symptomatic and asymptomatic KOA and to determine whether IVIM-DWI parameters can be used as an objective biomarker for symptomatic KOA. In total, 84 patients with symptomatic KOA, 43 asymptomatic KOA persons, and 30 healthy controls with MRI were retrospectively reviewed. Demographic, IPFP-synovitis, Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain sub-score, IPFP volume and depth and quantitative parameters of IVIM-DWI were collected. The chi-square test, Binary logistic regression and receiver operating characteristic curve (ROC) analysis were used for diagnostic performance comparison. The IPFP volume and depth were statistically significant differences between the non-KOA and sKOA groups (p<0.05). The IPFP PdWI hyperintense regions demonstrated significantly higher values of D and D* in the symptomatic KOA compared to those in the asymptomatic KOA (1.51±0.47 vs. 1.73±0.40 for D and 19.24±6.44 vs. 27.09±9.75 for D*) (both p<0.05). Multivariate logistic regression analyses showed that Higher D and D* values of IPFP hyperintense region were significantly associated with higher risks of knee pain (OR: 1.97; 95% CI: 1.21-3.19; p=0.006 for D and OR: 1.24; 95% CI: 1.09-1.41; p=0.001 for D*). Sensitivity and specificity of D value for symptomatic KOA were 80.28% and 83.33%, with an AUC of 0.78 (0.68-0.86). D* value had the sensitivity with 92.96% and a specificity of 58.33%, with an AUC of 0.82 (0.73-0.89) for symptomatic KOA. IVIM-DWI can be used as an additional functional imaging technique to study IPFP with signal abnormalities on PdWI, and the D and D* values may have potential value to predict the symptom in mild-to-moderate KOA patients.

Diffusion-weighted imaging versus non-contrast magnetic resonance imaging in the diagnosis of acute appendicitis during pregnancy

The aim of this study was to evaluate the diagnostic performance of diffusion-weighted imaging compared to non-contrast magnetic resonance imaging in the differential diagnosis of acute appendicitis in pregnant patients. A total of 72 pregnant patients with the suspicion of acute appendicitis who underwent magnetic resonance imaging combined with diffusion-weighted imaging examinations were enrolled in this retrospective study. Magnetic resonance imaging images (non-contrast and diffusion-weighted imaging sequences) were evaluated. Moreover, apparent diffusion coefficient ratios were estimated. The diagnostic performances of magnetic resonance imaging and diffusion-weighted imaging findings were statistically analyzed on the basis of surgical and follow-up results. Of 72 pregnant patients, 10 (14%) had acute appendicitis on magnetic resonance imaging and diffusion-weighted imaging. Among 10 patients with acute appendicitis, three (3/10) had perforation. diffusion-weighted imaging findings had higher sensitivity (90 versus 60%), negative predictive value (98.41 versus 93.94%), and accuracy (98.61 versus 94.44%) ratios compared to non-contrast magnetic resonance imaging in the diagnosis of acute appendicitis. There was one false-negative result on diffusion-weighted imaging. Diffusion restriction facilitated the detection of appendicitis. The apparent diffusion coefficient ratios were lower in acute appendicitis than in the normal appendix (0.70±0.19 versus 0.96±0.16) (p<0.05). With a shorter scan time and higher diagnostic accuracy, diffusion-weighted imaging can be useful for the early diagnosis of acute appendicitis and for planning appropriate management.

Surgical Outcomes of Cardiac Myxoma Resection Through Right Mini-Thoracotomy.

With recent advances in cardiac surgery through minimal access, mini-thoracotomy has emerged as an excellent alternative for cardiac myxoma resection. This study analyzed the surgical results of this approach, focusing on postoperative cerebral embolism and tumor recurrence. We retrospectively reviewed 64 patients (mean age, 56.0±12.1 years; 40 women) who underwent myxoma resection through mini-thoracotomy from October 2008 to July 2020. We conducted femoral cannulation and antegrade cardioplegic arrest in all patients. Patient characteristics and perioperative data, including brain diffusion-weighted magnetic resonance imaging (DWI) findings, were collected. Medium-term echocardiographic follow-up was performed. Thirteen patients (20.3%) had a history of preoperative stroke, and 7 (11.7%) had dyspnea with New York Heart Association functional class III or IV. Sixty-one cases (95.3%) had myxomas in the left atrium. The mean cardiopulmonary bypass and cardiac ischemic times were 69.0±28.6 and 34.1±15.0 minutes, respectively. Sternotomy conversion was not performed in any case, and 50 patients (78.1%) were extubated in the operating room. No early mortality or postoperative clinical stroke occurred. Postoperative DWI was performed in 32 (53%) patients, and 7 (22%) showed silent cerebral embolisms. One patient underwent reoperation for tumor recurrence during the study period; in that patient, a genetic study confirmed the Carney complex. Mini-thoracotomy for cardiac myxoma resection showed acceptable clinical and neurological outcomes. In the medium-term echocardiographic follow-up, reliable resection was proven, with few recurrences. This approach is a promising alternative for cardiac myxoma resection.