Presence Of Restricted Diffusion Research Articles

A sellar-suprasellar malignant optic pathway glioblastoma in the absence of prior radiation therapy: illustrative case.

To date, only a few cases of sellar and suprasellar glioblastomas have been reported even though high-grade glioma constitutes the most common adult brain tumor, commonly arising in the cerebral hemispheres. It arises de novo from astrocytes within the optic nerve, optic chiasm, or optic tracts and is quite challenging to diagnose and treat. To the authors' knowledge, there are 72 cases (including this one) of optic glioma malignancies in the medical literature, 30 corresponding to glioblastomas. The authors present the diagnostic considerations and challenges, management strategies, and clinical course of a very large sellar-suprasellar glioblastoma in a 19-year-female who had never received radiation therapy or prior surgery. Sellar-suprasellar glioblastomas, although extremely rare, are known to occur and pose challenges in their diagnosis and preoperative treatment planning. The presence of diffusion restriction on diffusion-weighted magnetic resonance imaging in a mass lesion that has ring and nodular postcontrast enhancement in addition to absent calcification on computed tomography should be alert to the possibility of a high-grade mass. This is extremely important for preoperative patient counseling and planning for the multimodal treatments, because sellar-suprasellar glioblastomas carry a poorer prognosis than the common benign mass lesions in the region.

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.

Predicting the WHO Grading of Pediatric Brain Tumors Based on Their MRI Appearance: A Retrospective Study.

The treatment of central nervous system (CNS) tumors constitutes a significant part of a pediatric neurosurgeon's workload. The classification of such neoplasms spans many entities. These include low- and high-grade lesions, with bothoccurring in the population of patients under 18 years of age. Magnetic resonance imaging serves as the imaging method of choice for neoplastic lesions of the brain. Through its different modalities, such as T1, T2, T1 C+,apparent diffusion coefficient (ADC), diffusion-weighted imaging (DWI), susceptibility-weighted imaging(SWI), fluid-attenuated inversion recovery(FLAIR), etc., it allows the medical team to plan the therapeutic process accordingly while also possibly suggesting the specific tumor subtype prior to obtaining a definitive histological diagnosis. We conducted a retrospective study spanning 32 children treated surgically for brain tumors between July 2021 and January 2023 who had a precise histological diagnosis determined by using the 2021 WHO Classification of Tumors of the Central Nervous System. We divided them into two groups (high-grade and low-grade tumors, i.e., WHO grades 1 and 2, and grades 3 and 4, respectively) and analyzed their demographic data and preoperative MRI results. This was done using the following criteria: sub or supratentorial location of the tumor; lesion is circumscribed or infiltrating; solid, cystic, or mixed solid and cystic character of the tumor; number of compartments in cystic lesions; signal intensity (hypo-, iso-, hyperintensitysequences: T1, T2, T1 C+); presence of restricted diffusion; the largest diameter of the solid component and/or the largest diameter of the largest cyst in the transverse section. Then, we examined the results to find any correlation between the lesions' morphologies and their final assigned degree of malignancy. We found that the only radiological criteria correlating with the final WHO grade of the tumor were an infiltrative pattern of growth (25% of low-grade lesions, 75% of high-grade; p = 0.006) and the presence of a cystic component in the tumor (in 68.75% of low-grade tumors and 43.75% of high-grade tumors; p = 0.041). The only other feature close to attaining statistical significance was diffusion restriction (33.3% of low-grade tumors, 66.7% high-grade; p = 0.055). Older children tended to present with tumors of lower degrees of malignancy, and there was a predominance of female patients (21 female, 11 male).

Role of Diffusion-Weighted Magnetic Resonance Imaging for Characterization of Mediastinal Lymphadenopathy.

To assess the diagnostic performance of diffusion-weighted (DW) magnetic resonance imaging (MRI) in the characterization of mediastinal lymph nodes and compare them with morphological parameters. A total of 43 untreated patients with mediastinal lymphadenopathy underwent DW and T2 weighted MRI followed by pathological examination in the period from January 2015 to June 2016. The presence of diffusion restriction, apparent diffusion coefficient (ADC) value, short axis dimensions (SAD), and T2 heterogeneous signal intensity of the lymph nodes were evaluated using receiver operating characteristic curve (ROC) and forward step-wise multivariate logistic regression analysis. The ADC of malignant lymphadenopathy was significantly lower (0.873 ± 0.109 × 10-3 mm2/s) than that of benign lymphadenopathy (1.663 ± 0.311 × 10-3 mm2/s) (p = 0.001). When an ADC of 1.0955 × 10-3 mm2/s was used as a threshold value for differentiating malignant from benign nodes, the best results were obtained with a sensitivity of 94%, a specificity of 96%, and an area under the curve (AUC) of 0.996. A model combining the other three MRI criteria showed less sensitivity (88.9%) and specificity (92%) compared to the ADC-only model. The ADC was the strongest independent predictor of malignancy. The addition of other parameters failed to show any increase in sensitivity and specificity.

UTILITY OF APPARENT DIFFUSION COEFFICIENTS WITH DIFFUSIONWEIGHTED MRI IN DIFFERENTIATING BENIGN AND MALIGNANT BONE LESIONS

OBJECTIVE:To evaluate the usefulness of diffusion-weightedMRIwith apparent diffusion co-efcients(ADC) cut-off value indifferentiatingbenignandmalignantbonelesions. MATERIALSAND METHODS: 58 patients with suspected bone tumours based on clinical examination and plain radiographs were included in the current study. They were subjected to routine MRI examination with inclusion of diffusion-weighted imaging, followed by histopathology for nal diagnosis.Allthe lesionswere assessed to see the presence of diffusion restriction if any. ADC values (mean, minimum and maximum) were obtained by two observers individually. Interobserver measurement and the ADC values in benign and malignant lesions were calculated. Receiver operating characteristic (ROC) analysis was done to determine optimal cut-off ADC values in distinguishing benign and malignant bone lesions. RESULTS: Of 58 lesions, there were 28 benign lesions and 30malignant lesions. Diffusion restriction was noted in 83.3% ofmalignant lesions whereas 57.1% of benign lesions did not show diffusion restriction. There were higher mean, minimum and maximum ADC values in benign lesions when compared with malignant lesions. With cut-off value of minimumADC as 0.92 x 10-3 mm2/sec to differentiate malignant and benign lesions, the sensitivity of 79% and specicity of 64% was obtained. CONCLUSIONS: DWIis useful in differentiating between benign and malignant lesions with diffusion restriction favoring malignancy. Higher mean, minimumandmaximumADCvalues are seen in benign lesions as compared tomalignant lesions. Even though, there isslight overlap inADCvalues of bothbenignandmalignantlesions,ADCvalueshelpintheirdifferentiation.

DIAGNOSTIC ROLE OF DIFFUSION-WEIGHTED IMAGE OF THE LIVER WITH MAGNETIC RESONANCE IMAGING IN PREDICTING ABSTINENCE DISORDERS IN PATIENTS WITH ALCOHOLIC LIVER DISEASE

Objective. To assess the diagnostic role of diffusion-weighted images of the liver with magnetic resonance imaging in predicting abstinence disorders in patients with alcoholic liver disease.&#x0D; Methods. A total of 122 patients with ALD aged 48±5.4 years were examined. The survey algorithm we used included: performing liver DWI with MRI (n=122) with b-value values of 100/600/1000, ultrasound of abdominal organs with clinical elastography – 97 (80%) patients. Trepan liver biopsy was chosen as a reference method (n=64).&#x0D; Results. The patients were monitored for 2.5 years. The terms of follow-up were selected individually, depending on the results of clinical and laboratory research methods. A high correlation was established (r=0.879), when comparing clinical elastography and quantitative indicators of DWI of the liver, at admission and during dynamic observation of patients, also at the middle level, the data obtained correlated with the results of trephine biopsy of the liver (r=0.721). After 3 months, 6 (15%) of 40 patients showed normalization of biochemical blood test parameters with no diffusion restriction according to the results of DWI of the liver. Based on the results obtained, a high correlation was noted between changes in the biochemical blood test and MRI data in the DWI mode. After 9 months of follow-up, according to DWI data, 34 patients showed persistence of cytolysis syndrome and limited diffusion on DWI of the liver. After collecting an additional history and clarifying the details of the lifestyle of the patients' relatives, it was found that these patients continued to consume alcoholic beverages against the background of the received treatment, which was manifested by the presence of diffusion restriction on MRI in the DWI mode, which was a magnetic resonance sign of the presence of inflammatory processes in the structure of the parenchyma liver. After 12 months, positive dynamics – the absence of diffusion restriction according to the results of DWI of the liver was noted in 34 patients, which indicates the effectiveness of using the qualitative characteristics of DWI of the liver to assess the violation of the abstinence regimen (AUROC=0.906 (95% CI 0.872-0.916)). But in 16 (13%) patients from this group, changes in the biochemical blood test were noted, but no diffusion limitation was noted according to the DWI of the liver. Patients (n=16) underwent a correction of the received treatment – after 1 month there was a positive trend. There was a correlation of quantitative parameters of DWI of the liver with clinical forms of ALD, regardless of the presence or absence of diffusion restriction (r=0.936). Next, we assessed the prognostic and diagnostic significance of the developed criteria for DWI of the liver for patients with ALD on admission. The results of the study indicated the effectiveness of using the diagnostic and prognostic model of MRI in the DWI mode for patients with ALD on admission and in dynamic observation.&#x0D; Conclusions. 1. A high correlation was found between the quantitative parameters of DWI of the liver and clinical elastography (r=0.879) at admission and follow-up. Average correlation relationship of DWI of the liver with the results of trephine biopsy of the liver in patients with ALD on admission and follow-up (r=0.721).&#x0D; &#x0D; There was a high correlation between the results of DWI of the liver on MRI with the data of clinical and laboratory parameters in dynamic observation of patients with ALD: no diffusion limitation – positive (r=0.887); yes – negative (r=0.887).&#x0D; The high prognostic and diagnostic value of DWI of the liver in assessing the violation of the abstinence regimen in patients with ALD was established (AUROC=0.906 (95% CI 0.872-0.916)).&#x0D; Prognostic and diagnostic criteria for liver DWI on MRI in patients with ALD at admission: qualitative characteristic – AUROC=0.846 (95% CI 0.811-0.862), quantitative characteristic – AUROC=0.909 (95% CI 0.879-0.912); with dynamic observation: qualitative characteristic – AUROC=0.949 (95% CI 0.907-0.965), quantitative characteristic – AUROC=0.917 (95% CI 0.876-0.932).&#x0D;

Clinico-radiological features of brain metastases from thyroid cancer.

The brain is an unusual site for distant metastases of thyroid cancer. The radiological features of brain metastases (BMs) have rarely been reported. Hemorrhage is frequently noted in BMs from thyroid cancer. This study aimed to investigate the clinico-radiological features of BMs from thyroid cancer and to determine the risk factors to predict BM hemorrhage.We retrospectively evaluated the MR images of 35 patients with BMs from thyroid cancer at our hospital from 2013 to 2020. The number, size, site, presence of extra-cranial metastasis, presence of perilesional edema, intra-tumoral hemorrhage, enhancement pattern, and presence of diffusion restriction on MRI were described. We further classified the thyroid cancers into hemorrhagic and nonhemorrhagic groups to investigate the factors associated with hemorrhage.54.29% of patients with thyroid BMs (19/35) had neurologic symptoms. 94.29% of patients (33/35) had extra-cranial metastases. The most common histology of primary thyroid cancer was papillary thyroid cancer (71.43%, 25/35), followed by anaplastic thyroid cancer (22.86%, 8/35). Thyroid cancer BMs were located mostly in the supra-tentorium (51.43%, 18/35) or both the supra and infra-tentorium (45.71%, 16/35). 60% of patients (21/35) showed hemorrhage within the BMs. The strongest predictor for BM hemorrhage was tumor size (variable importance: 50).Thyroid cancer BMs exhibit a bleeding tendency. Furthermore, larger BMs are more likely to have an intra-tumoral hemorrhage.

Hepatic sclerosed hemangioma and sclerosing cavernous hemangioma: a radiological study

PurposeTo investigate and compare the CT and MRI features of hepatic sclerosed hemangioma (HSH) and sclerosing cavernous hemangioma (SCH).Materials and methodsTwelve HSH cases and 36 SCH cases were included, the imaging findings on CT (9 HSH and 34 SCH) and MRI (8 HSH and 10 SCH) were analyzed. Qualitative image analysis included the location, size, shape, capsular retraction, density, calcification, signal intensity on T1-weighted image (T1WI) and T2-weighted image (T2WI), presence of diffusion restriction, apparent diffusion coefficient (ADC) map, transient hepatic attenuation difference around the lesion, and the dynamic enhancement patterns.ResultsThe presence of liver cirrhosis in patients with HSH (3/12) was higher than SCH (1/36) (P = 0.043). The morphology appearance before enhancement showed no significant difference between HSH and SCH. Moreover, SCH had a stronger trend of centripetal enhancement patterns of cavernous hemangiomas (83.3%) compared to HSH (25%) (P < 0.001). Due to more frequent atypical enhancement features, containing rim-like enhancement, no enhancement, and peripheral heterogeneous enhancement, the misdiagnosis rate of HSH (75%) was significantly higher than that of SCH (16.7%) (P < 0.001). Furthermore, the ADC values of HSH and SCH were both higher than that of the surrounding liver parenchyma (P = 0.009, P = 0.002); however, there was no significant difference in ADC values between themselves (P = 0.613).ConclusionSCH showed the same trend of centripetal enhancement characteristics as typical hemangioma, while HSH exhibited atypical enhancement features due to complete sclerosis. Higher ADC values might contribute to the identification of atypical HSH and SCH from malignancies.

Neuroimaging Findings in Rabies Encephalitis.

Rabies encephalitis is a near-fatal zoonotic disease that is usually diagnosed on clinical grounds in conjunction with characteristic history. Owing to its rapidly progressive nature, imaging is seldom performed, and hence a description of imaging findings in rabies encephalitis is anecdotal and limited. We describe MRI findings in eight confirmed rabies cases that presented to our institute over the last 21 years. Most of the patients' imaging patterns are in concordance with the described literature. However, we hereby demonstrate the involvement of novel structures like dentate nuclei, cranial nerves, and meninges besides the hot cross bun sign in the pons and the presence of diffusion restriction in many gray and white matter structures of the brain. Knowledge of the broad imaging spectrum of rabies may expedite the diagnosis, especially the paralytic form, which is prone to clinical misdiagnosis as Guillain-Barre syndrome or acute disseminated encephalomyelitis.

A prospective cohort study to assess the frequency and risk factors for calcification in single lesion parenchymal neurocysticercosis

BackgroundCalcified neurocysticercosis (NCC) predisposes patients to an enduring state of epilepsy. The predictors for calcification in parenchymal neurocysticercosis are not well defined. MethodIn this prospective cohort study, consecutive children with single-lesion parenchymal NCC were enrolled and followed up for one year. All patients were investigated with brain 3 T-MRI and electroimmunotransfer blot (EITB). Clinical follow-ups were performed every 3 months. Radiology was repeated at the 6-month and one-year follow-ups. The proportion of calcified lesions at one year and the predictors of calcification were studied. ResultDuring the study period from June 2013 to December 2015, 93 children with single lesion parenchymal NCC were enrolled. At presentation, 90 % of the lesions were in the colloidal stage, and 71 % of the lesions had moderate to severe perilesional oedema. All children had 6 months of follow-up, and 86 (92.5 %) had one year of follow-up. Seizure recurrence was present in 13 (14 %) children. Follow-up radiology at one year showed lesion resolution in 51 (59 %) lesions and calcification in 28 (32.5 %) lesions. Children with calcified lesions during follow-up had a higher odds of seizure recurrences {OR, 95 % CI 3.6(2.3–5.6)}. The presence at baseline of diffusion restriction {OR, 95% CI 2.9 (1.01–8.8)}, scolex or wall calcification in the T2 Star weighted angiography MRI images {OR, 95% CI 3.7 (1.7–8.2)} and >10 mm size of the lesion {OR, 95 % CI 2.4 (1.2–5.01)} predicted lesion calcification. ConclusionChildren with calcification of the parenchymal NCC lesions have a higher risk for seizure recurrence during follow-up. The presence of diffusion restriction, calcified nidus in the colloidal nodular stage, and >10 mm size of the lesion at baseline predicted calcification of the lesion during follow-up.

Morphological and biochemical heterogeneity in the tissue of pancreatic ductal adenocarcinoma (PDAC) according to structural and spectrometric MRI data.

e16727 Background: Comparing the MRI characteristics of pancreatic tissue in normal, solid adenocarcinomas and chronic pancreatitis in a multiparametric study, the radiologist needs tools that reduce the subjective component in making a diagnostic decision. The study is devoted to the assessment of structural heterogeneity, diffusion coefficient, lipid and lactate concentration according to MR spectroscopy in vivo. PDAС cells are proliferating and surviving within a particularly severe microenvironment characterized by relative hypovascularity, hypoxia, and nutrient deprivation. In this case cells have to show biochemical flexibility (survival phenotype) in order to adapt to unusual conditions. Methods: 20 patients with pancreatic adenocarcinomas (PDAC), 10 patients with chronic pancreatitis and 10 patients with unchanged pancreas were examined MRI using Signa HD 1.5 t General Electric. The results of their multiparametric imaging and NMR spectroscopy were investigated and compared.The heterogeneity coefficients (HC) were measured as ratio standard deviation in small region of interest to signal intensity in T1FS and T2. Lipid concentration was measured by Dixon method as the pancreatic -to-splenic attenuation ratio. Results: In a small sample, we observed a significant increase in HC in chronic pancreatitis, and in solid tissue in adenocarcinomas in comparison with normal tissue, depending on the main source of the MR signal (hydrogen in the macromolecules or hydrogen of water and fat). In adenocarcinomas, an increase in the signal from lipids (lip13a) peak was revealed, with a decrease in the total lipid concentration. A decrease in lipid concentration in the tumor in the presence of diffusion restriction (ADC 0,001-0,0016 мм2/s) and the appearance of a peak of lactate may be a biochemical marker of adenocarcinoma. In chronic pancreatitis, an increase in the mass fraction of lipids was revealed. Conclusions: The results obtained in current and future in-depth studies are promising for creation of a metabolically oriented diagnostic model of pancreatic cancer.

Structural signature of sporadic Creutzfeldt-Jakob disease.

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rapidly progressive neurodegenerative disease caused by an abnormal isoform of the human prion protein. Structural magnetic resonance imaging in patients with pathologically confirmed sCJD was compared with cognitively normal individuals to identify a cortical thickness signature of sCJD. This retrospective cross-sectional study compared patients with autopsy-confirmed sCJD with dementia (n = 11) with age- and sex-matched cognitively normal individuals (n = 22). We identified regions of interest (ROIs) in which cortical thickness was most affected by sCJD. Within patients with sCJD, the relationship between ROI cortical thickness and clinical measures (disease duration, cerebrospinal fluid tau and diffusion-weighted imaging abnormalities) was evaluated. Compared with cognitively normal individuals, patients with sCJD had significantly reduced cortical thickness in multiple ROIs, including the fusiform gyrus, precentral gyrus, precuneus and superior temporal gyrus bilaterally; the caudal middle frontal gyrus, superior frontal gyrus, postcentral gyrus, inferior temporal gyrus and transverse temporal gyrus in the left hemisphere; and the superior parietal lobule in the right hemisphere. Only one patient with sCJD had co-pathology consistent with Alzheimer's disease. Reduced cortical thickness did not correlate with disease duration, presence of diffusion restriction or elevated cerebrospinal fluid tau. Cortical signature changes in sCJD may reflect brain changes not captured by standard clinical measures. This information may be used with clinical measures to inform the progression of sCJD and patterns of prion protein spread throughout the brain. These results may have implications for prediction of symptomatic progression and plausibly for development of therapeutic strategies.

The MRI characteristics of non-mass enhancement lesions of the breast: associations with malignancy.

The American College of Radiology updated the terms used for expressing the imaging characteristics of non-mass enhancement (NME) lesions in the fifth edition of the breast imaging-reporting data system (BI-RADS) lexicon. Both the distribution and internal enhancement descriptors were revised for NME lesions. Our aim was to determine the MRI characteristics of NME lesions and to investigate their association with malignancy. The MRI results of 129 NME lesions were retrospectively evaluated. The medical files, biopsy results and follow-up findings of lesions were recorded. Patients who had benign biopsy and those who had stable or regressed lesions during follow-up were classified as benign. All MRI results had been obtained with a 1.5 Tesla Signa HDx MR system (GE Healthcare). Segmental and diffuse distribution along with clustered-ring internal enhancement were significantly associated with malignancy, while linear distribution and homogeneous enhancement pattern were associated with benignancy. Additionally, the plateau type (Type II) curve was significantly more frequent in malignant lesions. There was no association between the presence of cystic structures and the benign/malignant nature of the lesion. However, multivariate logistic regression showed that only segmental distribution and diffusion restriction were associated with malignancy. In the current study, segmental distribution, clustered-ring enhancement, Type II dynamic curve and the presence of diffusion restriction were found to be associated with malignancy. There is a requirement for multicenter studies which include higher numbers of patients in order to better evaluate lesions with rarer characteristics for distribution and enhancement pattern. Our aim in this study was to investigate the MRI characteristics of NME lesions. We have reported the MRI findings of NME lesions and have found that segmental distribution and clustered-ring enhancement patterns are significantly more frequent in malignant lesions.

Assessment of normal jejunum with diffusion-weighted imaging on MRE in children.

Diffusion restriction has been utilized as a marker for bowel inflammation on magnetic resonance enterography (MRE). However, diffusion restriction has been seen in otherwise normal appearing small bowel in patients without active inflammation, with little published data on this subject. Assess diffusion restriction in normal loops of jejunum and to determine if there is a correlation to luminal distention, age, magnet field strength, slice thickness, and bowel segment location. A retrospective analysis of subjects with a normal MRE and clinical work-up was performed. The abdomen was divided into four quadrants. If available, two loops of jejunum were randomly chosen in each quadrant. Two radiologists evaluated the loops of jejunum for distension, wall thickness, enhancement and diffusion restriction. Disagreement was resolved by consensus. Presence of diffusion restriction was correlated with luminal distension, age, magnet field strength, slice thickness and abdominal quadrant. One hundred ninety-seven loops of jejunum were evaluated in 39 subjects. Fifteen subjects (38.5%) had jejunal loops with diffusion restriction for a total of 28 loops. There was no correlation between diffusion restriction and luminal distension, age, magnet field strength or quadrant location (P>0.05, Pearson chi-squared test or Student's t-tests). Of the 15 subjects with a loop demonstrating diffusion restriction, additional loops with diffusion restriction were found in 40%. There was a very weak trend observed for greater slice thickness in patients with jejunal diffusion restriction (Student's t-test, P=0.10). Jejunal diffusion restriction is a common finding in children with no clinical evidence of bowel pathology, irrespective of patient age, luminal distension, location of bowel loop and magnetic field strength. Further studies may be valuable in assessing the impact of slice thickness on subjective diffusion restriction in the jejunum.

JOURNAL CLUB: Primary Anorectal Melanoma: MRI Findings and Clinicopathologic Correlations.

The purpose of this study is to evaluate the MRI features of primary anorectal malignant melanoma and to correlate these features with its clinical and pathologic characteristics. The medical records of 12 patients (five men and seven women; mean age [± SD], 60.8 ± 10.0 years) with pathologically proven primary anorectal melanoma were retrospectively reviewed. MRI findings were analyzed to determine the shape, size, distance from the anal verge, presence of perirectal or anal infiltration, signal intensity on T1- and T2-weighted images, presence of diffusion restriction, contrast enhancement pattern of the lesion, presence of lymphadenopathy, and occurrence of bowel obstruction. Subsequent follow-up data for the patients were recorded. The most common presentation was hematochezia (41.7% of patients). Common findings on MRI included a large intraluminal polypoid mass (75.0% of lesions) with little perirectal or anal infiltration (100.0%), T1 hyperintensity (66.7%), high T2 signal intensity (54.5%) or mixed T2 signal intensity (45.5%), restricted diffusion (100.0%), and hyper-enhancement (100.0%). The mean length, width, and depth of these masses were 3.5, 2.9, and 2.3 cm, respectively. The mean distance from the anal verge was 1.8 cm. Lymphadenopathy was frequently identified (75.0% of cases), with lymph nodes larger than 2 cm noted in 28.5% of cases and most commonly involving the perirectal area (77.8% of cases). No colonic obstructions were observed. The mean patient follow-up was 32.7 months. A total of 25.0% of patients died as a result of disease progression. The possibility of the presence of anorectal melanoma should be considered for patients with a bulky intraluminal polypoid mass in the anorectum without colonic obstruction, with the mass showing T1 hyperintensity, high or mixed signal T2 intensity, hyperenhancement, minimal perirectal or anal infiltration, and lymphadenopathy.

Brain Imaging in Cases with Positive Serology for Dengue with Neurologic Symptoms: A Clinicoradiologic Correlation.

Dengue is a common arboviral disease, which uncommonly involves the brain. There has been a recent surge in dengue cases and dengue-related deaths in tropical countries. The aim of this study was to describe brain imaging findings in patients with dengue infection having neurologic symptoms. Thirty-five patients with positive serology for dengue with CNS symptoms undergoing imaging of the brain were included in the study. Clinical, laboratory, and imaging parameters were assessed and correlated to poor outcome. A Glasgow Coma Scale score of ≤12 at presentation, clinical classification of severe-type dengue, and the presence of acute renal failure were associated with poor outcome. Imaging parameters associated with poor outcome were involvement of the thalami and cerebellar peduncles and the presence of diffusion restriction and hemorrhagic foci in the brain parenchyma. Although not specific, dengue infection has imaging findings that can be used to narrow down the differential list and help in prognostication.

Differentiating primary hepatic angiosarcomas from hemangiomatosis and epithelioid hemangioendotheliomas using gadoxetic acid-enhanced and diffusion-weighted MR imaging.

To assess the value of gadoxetic acid-enhanced and diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating primary hepatic angiosarcomas from hemangiomatosis and epithelioid hemangioendotheliomas (EHEs). We reviewed MR images of seven patients with pathologically determined hepatic angiosarcomas, 11 patients with hemangiomatosis, and five patients with EHEs. Two radiologists assessed morphologic features, signal intensity (SI), enhancement patterns, and the presence of diffusion restriction by consensus and compared between angiosarcoma vs hemangiomatosis and angiosarcoma vs EHEs. Angiosarcomas more frequently showed mixed well- and ill-defined margins (6, 85.7%), mixed strong and intermediate-high SI (5, 71.4%) on T2-weighted images, mixed peripheral and/or central nodular and rim and/or target enhancement (5, 71.4%), and mixed presence and absence of diffusion restriction (7, 100%) compared with hemangiomatosis and EHEs (P<0.05). The overall survival rate in patients with angiosarcomas was 42.9% at 3months and 14.3% at 14months, whereas all patients with EHEs were alive during the follow-up period from 4 to 43months (P=0.002). Gadoxetic acid-enhanced and DW MR imaging may help differentiate primary hepatic angiosarcomas with hemangioma-like appearance, EHE-like appearance, or both; and poor prognosis from hemangiomatosis and EHEs.

Toxins in Brain! Magnetic Resonance (MR) Imaging of Toxic Leukoencephalopathy - A Pictorial Essay.

SummaryToxic leukoencephalopathy results from damage to the white matter caused by various toxins. It manifests itself as white matter signal abnormalities with or without the presence of restricted diffusion. These changes are often reversible if the insulting agent is removed early, with the exception of posthypoxic leukoencephalopathy that can manifest itself 1–2 weeks after the initial insult. However, many other potential causes of white matter signal abnormalities can mimic the changes of toxic leukoencephalopathy. Thus, familiarity with the causes, clinical presentation and particularly imaging findings of toxic leukoencephalopathy is critical for early treatment and improved prognosis. The purpose of this pictorial essay is to familiarize the reader with the various causes of toxic leukoencephalopathy along with its differential diagnoses and mimics.

Diffusion-weighted imaging in quiescent Crohn's disease: correlation with inflammatory biomarkers and video capsule endoscopy

To investigate the role of restricted diffusion in quiescent Crohn's disease (CD) patients and its association with inflammatory biomarkers and endoscopic disease. Fifty-two quiescent CD patients prospectively underwent magnetic resonance enterography (MRE) and video capsule endoscopy (VCE) and were tested for the inflammatory biomarkers, faecal calprotectin (FCP) and C-reactive protein (CRP). Restricted diffusion in the distal ileum was qualitatively (absence/presence) and quantitatively (apparent diffusion coefficient [ADC]) assessed by two readers. The VCE-based Lewis score was calculated for the distal ileum. Restricted diffusion sensitivity and specificity for VCE ulcerations were assessed for patients with elevated (>100 μg/g) or normal (<100 μg/g) FCP. Receiver operating characteristic (ROC) curve was used to assess the ability of ADC to identify patients with concurrent VCE ulceration and elevated FCP. The sensitivity and specificity of restricted diffusion for patients with VCE ulceration were higher in patients with elevated FCP (reader 1: 71.4%, 80%, reader 2: 76.2%, 100%, respectively) compared to patients with normal FCP (reader 1: 46.2%, 61.5%; reader 2: 15.4%, 76.9%, respectively). The ADC had a high diagnostic accuracy for identifying patients that had concurrent VCE ulceration and elevated FCP (reader 1: AUC=0.819, reader 2: AUC=0.832). In quiescent CD patients, the presence of restricted diffusion is suggestive of an active inflammation, associated with elevated FCP. Thus, DWI may serve as a clinical tool in the follow-up of these patients, implying subclinical inflammatory flares.

Diffusion restriction in the corticospinal tracts and the corpus callosum in neonates after cerebral insult

BackgroundIn neonatal brains diffusion restriction, which is not limited to the region of insult, but is also found in distant locations from it seems to be a frequent finding, called pre-Wallerian degeneration. ObjectivesThe purpose of this study was to describe these findings and to estimate the frequency of their occurrence with an attempt to determine their clinical significance. Methods125 brain MRI examinations of neonates with confirmed brain damage performed or consulted in our Institute were retrospectively reviewed, focusing on the presence of restricted diffusion in corticospinal tracts (CST) and corpus callosum (CC). Apparent diffusion coefficients (ADC) were measured in callosal splenium and compared to normal neonatal brains. ResultsRestricted diffusion was found in 21 newborns (16.8%): in 4 in CST (3.2%), in 5 in CC (4.0%), in 12 in both (9.6%). Mean ADC value in CC was 0.638, standard deviation (SD): 0.211μm2/s and in the control group 0.995, SD: 0.162μm2/s (p=0,001). ConclusionsNeonatal brain MRI should be searched for DWI abnormalities which are not rare and require careful studying of ADC maps. Diffusion restriction in the corpus callosum and/or corticospinal tracts below the region of insult should not be mistaken for acute ischemia as it most likely reflects early phase of secondary neuronal degeneration called pre-Wallerian degeneration. This finding helps in prognostication and guides the management of the affected neonates.