MR Features Research Articles

Diagnostic Value of Ultrasonography and MR in Antenatal Diagnosis of Placenta Accreta Spectrum

AbstractThe aim of this study was to compare the accuracy of ultrasonography and magnetic resonance imaging (MR) in the antenatal diagnosis of placenta accreta. We also determined the most relevant sonographic and MR features associated with the diagnosis of placenta accreta. In a prospective observational study approved by the Ethical Board of the Radiology Department, 109 pregnant women who were at high risk for Placenta Accreta were enrolled. The placentas of all cases were scanned using both gray-scale and color Doppler transabdominal sonography. MR was performed when sonographic findings were equivocal or inconclusive. The sonographic and MR features were compared with the final pathologic or clinical findings. The sensitivity and specificity were calculated for both sonography and MR. The role of each sonographic and MR feature was calculated by logistic regression. P < 0.05 was considered as the significance level. The sensitivity and specificity of ultrasonography for the diagnosis of Placenta Accreta spectrum were 87% and 85% (P < 0.001), while those of MR were 100% and 42% (P = 0.1), respectively. In ultrasonography, myometrium thickness ≤ 1 mm with a sensitivity of 83% (95 CI: 0.765, 0.927) and loss of retroplacental clear space with a sensitivity of 81% (95 CI: 0.755, 0.920) had the best sensitivity for the detection of the placental invasion. On MR, the heterogeneous signal intensity of placenta and uterine bulging with a sensitivity of 87% (95 CI: 0.698, 1.04) had the best sensitivity. Placenta accreta can be successfully detected prenatally using ultrasound. MR is useful in equivocal cases.

MRI wrist in early rheumatoid arthritis: reduction in inflammation assessed quantitatively during treatment period correlates best with clinical improvement.

To investigate (a) which MR features of inflammation (synovitis, tenosynovitis, perfusion) correlate with clinical/serological features in early rheumatoid arthritis (ERA) before, during and after 1year of treatment and (b) whether quantitative or semi-quantitative measures of inflammation on magnetic resonance imaging (MRI) provides the highest correlation in this regard. One hundred one ERA patients (76 females, 25 males, mean age, 53 ± 12years) underwent clinical/serological testing and 3T dynamic contrast-enhanced MRI of the most symptomatic wrist. Seventy-seven of the 101 patients completed 1year of treatment, followed by repeat MR examination. Clinical/serological parameters were correlated with semi-quantitative/quantitative MR measures of inflammation at baseline, during and after 1year of treatment. Spearman's correlation was applied. Quantitative measures of inflammation correlated better with clinical/serological parameters than semi-quantitative measures, with the highest correlations being for relative change during treatment. Pain reduction correlated with reduced tenosynovitis volume (r = 0.41). Reduction in disease activity correlated with reduction in synovitis volume (r = 0.66) or synovial perfusion parameters (r = 0.58). Decrease in early morning stiffness correlated with decrease in perfusion parameters (r = 0.46). Reduction in ESR and CRP correlated with decrease in synovial volume (r = 0.40 and r = 0.41, respectively). In ERA patients, quantitative assessment of inflammation on MRI correlated better with clinical parameters than semi-quantitative assessment. Relative change during treatment yielded the highest correlation. Decrease in tenosynovitis correlated best with reduction in pain while decrease in synovitis volume and perfusion correlated best with reduction in disease activity, early morning stiffness (perfusion), or serological parameters (synovitis volume).

Assessment of malignant potential in intraductal papillary mucinous neoplasms of the pancreas using MR findings and texture analysis.

To investigate the utility of MR findings and texture analysis for predicting the malignant potential of pancreatic intraductal papillary mucinous neoplasms (IPMNs). Two hundred forty-eight patients with surgically confirmed IPMNs (106 malignant [invasive carcinoma/high-grade dysplasia] and 142 benign [low/intermediate-grade dysplasia]) and who underwent magnetic resonance imaging (MRI) with MR cholangiopancreatography (MRCP) were included. Two reviewers independently analyzed MR findings as proposed by the 2017 international consensus guidelines. Texture analysis of MRCP was also performed. A multivariate logistic regression analysis was used to identify predictors for malignant IPMNs. Diagnostic performance was also analyzed using receiver operating curve analysis. Among MR findings, enhancing mural nodule size ≥ 5mm, main pancreatic duct (MPD) ≥ 10mm or MPD of 5 to 9mm, and abrupt change of MPD were significant predictors for malignant IPMNs (p< 0.05). Among texture variables, significant predictors were effective diameter, surface area, sphericity, compactness, entropy, and gray-level co-occurrence matrix entropy (p< 0.05). At multivariate analysis, enhancing mural nodule ≥ 5mm (odds ratios (ORs), 6.697 and 6.968, for reviewers 1 and 2, respectively), MPD ≥ 10mm or MPD of 5 to 9mm (ORs, 4.098 and 4.215, and 2.517 and 3.055, respectively), larger entropy (ORs, 1.485 and 1.515), and smaller compactness (ORs, 0.981 and 0.977) were significant predictors for malignant IPMNs (p< 0.05). When adding texture variable to MR findings, diagnostic performance for predicting malignant IPMNs improved from 0.80 and 0.78 to 0.85 and 0.85 in both reviewers (p< 0.05), respectively. MRCP-derived texture features are useful for predicting malignant IPMNs, and the addition of texture analysis to MR features may improve diagnostic performance for predicting malignant IPMNs. • Among the MR imaging findings, an enhancing mural nodule size ≥ 5mm and dilated main pancreatic ducts are independent predictors for malignant IPMNs. • Greater entropy and smaller compactness on MR texture analysis are independent predictors for malignant IPMNs. • The addition of MR texture analysis improved the diagnostic performance for predicting malignant IPMNs from 0.80 and 0.78 to 0.85 and 0.85, respectively.

POLYMORPHISM OF ESTERASE ISOENZYMES OF RIPE SEEDS OF SAMPLES OF RADISH (Raphanus sativus L.)

A biochemical approach was used to assess the genetic variability of the seed radish (Raphanus sativus L.) accessions which are distinguished by a wide variety of morphological characters. It is known that the esterase complex in plants has intraspecific specificity; in addition, these enzymes are characterized by tissue specificity. Earlier, the samples of the collections of the genetic resources of the radish were never evaluated for the presence of isozyme forms of esterases in mature seeds of this culture. The establishment of the general variability of isoenzyme systems and the identification of their genetic control make it possible to reveal the subtle mechanisms of the organism's relationship with the environment and homeostasis, which is especially important for long-term storage of samples in genetic seed collections. The development of effective biochemical markers for the rapid assessment of collection, as well as genetically and breeding significant material is also essential. This work allows us to fill the gap that exists in relation to the samples of genetic resources of the radish. From the collection of the Federal Research Center Vavilov All-Russian Institute of Plant Genetic Resources (VIR), 49 radish accessions were selected, belonging to three subspecies, divided according to geographic principle as Chinese, Japanese and European radish. All esterase isozymes of seeds were separated using native vertical electrophoresis in polyacrylamide gel followed by processing for nonspecific esterase. According to their esterase composition, all accessions were subdivided into 7 zymotypes, differing from each other by the presence or absence of certain zones. In total, in the esterase complex of radish seeds, 5 main isozymes with different molecular weights varying from 45.3 kDa to 35.0 kDa were found. All five zones were characterized by a high level of polymorphism among the samples. Based on the composition of isozymes, all genotypes formed 7 zymotypes. Zymotype No. 1, represented by the maximum number of esterases (5 zones), comprised of 43 % of the total number of genotypes. Zymotype No. 2 constituted 33 % of all samples. The rarest zymotypes No. 5 and No. 7 (4 %) differed in the minimum amount of esterase enzymes (2 zones each). Zymotypes No. 2 and No. 4 were characterized by 4 zones. Representatives of two groups, No. 3 and No. 6 had 3 zones in their esterase complex. The quantitative ratio of all esterase zones varied greatly in the studied samples. The minimum content (4.78 %) was found for the B5 zone, the maximum amount (67.44 %) was found for the B1 zone. The prevalence of each zone among all studied samples ranged from 13 to 23 %. Zones B3 (Mr = 39.7 kDa) and B4 (Mr = 37.1 kDa) were the most common among all esterase isozymes; these zones were observed in 23 % of genotypes. For 22 % of representatives, the B2 zone was characteristic (Mr = 42.9 kD). Zones B1 (Mr = 45.3 kD) and B5 (Mr = 35 kD) were less common, 19 % and 13 %, respectively. The average heterozygosity of isozygous forms of esterases of the studied radish samples was Htotal = 0.212, with variance for the same samples Var(Htotal) = 0.0007. Cluster analysis of esterase enzymes divided the studied set of radish samples into European and Asian subspecies and varieties, and together with phenotypic traits, it allowed constructing a dendrogram corresponding to the botanical, agrobiological and geographical location of the samples. It should be noted that the accessions of the European subspecies radish are located in two clusters, and the accessions of Russian origin form a separate group in the first cluster, and the samples of European origin are grouped in the third cluster which also includes Japanese radishes of European origin. Perhaps this division is associated with the peculiarities of the selection process in creating these samples. Based on the data obtained, esterase enzymes are recommended as biochemical markers in genetic selection experiments.

MRI following medial patellofemoral ligament reconstruction: assessment of imaging features found with post-operative pain, arthritis, and graft failure

To assess MR features following MPFL reconstruction and determine their influence on post-operative pain, progressive arthritis, or graft failure. Retrospective study on 38 patients with MPFL reconstruction and a post-operative MRI between January 2010 and June 2019. Two radiologists assessed MPFL graft signal, graft thickness, femoral screw, femoral tunnel widening, and patellofemoral cartilage damage. The third performed patellofemoral instability measurements. All three assessed femoral tunnel position with final result determined by majority consensus. Imaging findings were evaluated in the setting of post-operative pain, patellofemoral arthritis, and MPFL graft failure including need for MPFL revision. Statistics included chi-square, Fisher's exact test, t test, and kappa. Mean graft thickness was 6.0 ± 1.8mm; 24% of the grafts were diffusely hypointense. Mean femoral tunnel widening was 2.5 ± 1.8mm; 34% of the femoral screws were broken or extruded. Fifty-two percent of the patients had no interval cartilage change. Non-anatomic femoral tunnels were found in 66% of patients, including in all 9 patients requiring revision MPFL reconstruction (p = 0.013). Revised MPFL grafts had more abnormal femoral screws compared to those that did not (67% vs. 24%) (p = 0.019). Other MR features did not significantly influence the evaluated outcomes. The need for revision MPFL reconstruction occurs more frequently when there is a non-anatomic femoral tunnel and broken or extruded femoral screws. The appearance of the MPFL graft itself is not an influencing factor for post-operative pain, progression of patellofemoral arthritis, or graft failure.

Multimodal MR Features of 8 Cases of Epithelioid Glioblastoma.

Purpose The MRI features of epithelioid glioblastoma (eGBM) were analyzed. The apparent diffusion coefficient (ADC), MR perfusion-weighted imaging (PWI), and magnetic resonance spectroscopy (MRS) findings were quantitatively analyzed.Methods The MRI images of 8 cases of eGBM were analyzed retrospectively. The location and edge, signal, peritumoral edema, adjacent meningeal invasion, and enhancement of the lesions were observed. The ADC value, relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and N-acetylaspartate/acetylcholine (NAA/Cho) value were analyzed.Results Among the 8 patients, the tumors were mainly located in the temporal lobe (n = 3), frontal lobe (n = 3), and parietal lobe (n = 2). The lesion boundary was clear in 6 cases and unclear in 2. The lesions were superficial in 5 cases and in the deep white matter in 3. Internal hemorrhage was observed in 4 cases. There was cystic necrosis in 7 cases, and only 1 case was solid without cystic necrosis. There was no edema around the lesion in 1 case, severe edema in 5, and moderate edema in 2. In 4 cases, the adjacent meninges were involved, and in 1 case, the ependyma was involved. Two patients developed leptomeningeal metastasis within 2 months after the operation. The average ADC value of the tumor parenchyma among all 8 patients was7.15 × 10−4 mm2/s,which was 17.6% lower than that of the contralateral side. The Cho/NAA metabolite ratio was 5.27 and 0.81 in the lesions of 2 patients. The rCBV was 3.51 ml/100 g and 3.32 ml/100 g of lesions in 2 patients; these values were 36% and 29% higher, respectively, than those of the contralateral side. The rCBF was 31.5 ml/100 g/min and 82.1 ml/100 g/min of lesions in two patients; these values were 49% and 203% higher, respectively, than those of the contralateral side.Conclusion eGBM characteristics include a superficial location, easy cyst degeneration, easy necrosis and hemorrhage, and clear boundaries. It easily invades adjacent meninges and shows cerebrospinal fluid dissemination and metastasis. Combining new MR techniques, such as ADC values, PWI, and MRS, could be helpful for improving diagnostic accuracy.

Inherited paediatric neurometabolic disorders, can brain magnetic resonance imaging predict?

Objectives:To evaluate diagnostic capability of brain magnetic resonance imaging (MRI) in detection of inherited neurometabolic disorders.Methods:This retrospective observational study was performed in Radiology Department at our Hospital in Dhahran, from January 2013 to January 2020. We evaluated brain MRIs of children (under 5) who were referred to pediatric neurology for clinical suspicion of neuro-developmental delay and metabolic disease. Known perinatal ischemia and birth trauma cases were excluded. Imaging criteria included: (i) bilateral symmetric white matter signal abnormality, (ii) diffusion restriction affecting bilateral deep grey nuclei with or without brainstem involvement, (iii) brain atrophy or edema with abnormal white matter signal, (iv) characteristic MR spectroscopic finding. Presence of any one of these findings was considered positive for neurometabolic disease. Two neuroradiologists interpreted MRIs with substantial interobserver agreement. Diagnoses were confirmed on biochemical/ metabolic screening and genetic testing. A 2 × 2 contingency table was used for results. Chi square test was used to determine association.Results:Out of 133 cases, 72 (49 males, 90% AR) were found to have neurometabolic disorders. Sensitivity, specificity, positive and negative predictive values were calculated as 81.94% (CI, 71.11-90.02), 67.21% (CI, 54.00-78.69), 74.68% (CI, 66.96-81.11) and 75.93% (CI, 65.16-84.17) respectively. Findings were found significant (p-value=0.0001).Conclusion:Brain MRI can help to predict inherited neurometabolic disorders considering certain findings.

Hemorrhagic Cysts and Other MR Biomarkers for Predicting Renal Dysfunction Progression in Autosomal Dominant Polycystic Kidney Disease.

Screening for rapidly progressing autosomal dominant polycystic kidney disease (ADPKD) is necessary for assigning and monitoring therapies. Height-adjusted total kidney volume (ht-TKV) is an accepted biomarker for clinical prognostication, but represents only a small fraction of information on abdominal MRI. To investigate the utility of other MR features of ADPKD to predict progression. Single-center retrospective. Longitudinal data from 186 ADPKD subjects with baseline serum creatinine, PKD gene testing, abdominal MRI measurements, and ≥2 follow-up serum creatinine were reviewed. 1.5T, T2 -weighted single-shot fast spin echo, T1 -weighted 3D spoiled gradient echo (liver accelerated volume acquisition) and 2D cine velocity encoded gradient echo (phase contrast MRA). Ht-TKV, renal blood flow (RBF), number and fraction of renal and hepatic cysts, bright T1 hemorrhagic renal cysts, and liver and spleen volumes were independently assessed by three observers blinded to estimated glomerular filtration rate (eGFR) data. Linear mixed-effect models were applied to predict eGFR over time using MRI features at baseline adjusted for confounders. Validation was performed in 158 patients who had follow-up MRI using receiver operator characteristic, sensitivity, and specificity. Hemorrhagic cysts, fraction of renal and hepatic cysts, height-adjusted liver and spleen volumes were significant independent predictors of future eGFR (final prediction model R2 = 0.88 P < 0.05). The number of hemorrhagic cysts significantly improved the prediction compared to ht-TKV in predicting future eGFR (area under the curve [AUC] = 0.94, 95% confidence interval [CI]: 0.9-0.94 vs. R2 = 0.9, 95% CI: 0.85-0.9, P = 0.045). For baseline eGFR ≥60 ml/min/1.73m2 , sensitivity for predicting eGFR<45 ml/min/1.73m2 by ht-TKV alone was 29%. Sensitivity increased to 72% with all MRI variables in the model (P < 0.05 = 0.019), whereas specificity was unchanged, 100% vs. 99%. Combining multiple MR features including hemorrhagic renal cysts, renal cyst fraction, liver and spleen volume, hepatic cyst fraction, and renal blood flow enhanced sensitivity for predicting eGFR decline in ADPKD compared to the standard model including only ht-TKV. Level of Evidence 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:564-576.

Budd-Chiari Syndrome: The “inferior vena cava reverse-flow” sign and “jet-blood” sign on CT and MRI

ObjectiveTo investigate the CT and MR features of “inferior vena cava(IVC) reverse-flow” sign and “jet-blood” sign in Budd-Chiari Syndrome (BCS). MethodsThe liver CT and/or MRI plain scan and dynamic enhancement of 107 cases of BCS diagnosed by DSA and/or clinic were collected, including 17 patients with hepatic vein obstruction type, 79 patients with IVC obstruction type, and 11 patients with mixed type. The manifestations of IVC reverse-flow sign and jet-blood sign in the latter two type BCS (90cases) imaging were analyzed. Results1) The incidence of IVC reverse-flow sign in the IVC obstruction type and mixed type was 93.3 %(83/90), which was manifested as: The contrast agent was shown below the level of renal veins in the hepatic arterial phase enhancement, while no contrast agent was shown above it at the same time. 2) The incidence of jet-blood sign in membrane-perforated subtype was 100 %(15/15) or 16.7 %(15/90), which was manifested as: The low density/signal dots appeared within full of contrast agent at the superior liver segment IVC on axial slices in arterial phase of CT/MRI enhancement, or the low signal line within agent presented above the IVC membrane on coronal image in equilibrium phase of MR enhancement. 3) Other imaging findings: 75 cases of membrane, 18 cases of membrane calcification, 27 cases of abnormal hepatic vein, 76 cases of abnormal structure of IVC, 18 cases of thrombus/cancer embolus in hepatic vein and/or IVC. There were 65 cases of abnormal liver appearance; 71 cases of abnormal liver enhancement; 21 cases of hepatic vein unsynchronous enhancement. Anastomotic branches among the hepatic veins open with comma sign in 54 cases; dilatation of intraspinal and paravertebral veins, azygos and hemiazygos veins in 90 cases(100 %, 90/90) or 96 cases(89.7 %, 96/107). ConclusionsThe “IVC reverse-flow” sign is a specific CT and MR sign of IVC type and mixed type BCS, and the “jet-blood” sign is a characteristic CT and MR sign of membrane-perforated subtype BCS.

Diagnostic approach to primary retroperitoneal pathologies: what the radiologist needs to know.

Retroperitoneal soft tissue lesions represent a wide range of disease processes with overlapping imaging findings. Familiarity with the CT and MR characteristics of these conditions is important to guide clinical evaluation. We review the tissue types, characteristic clinical, demographic, and imaging features of retroperitoneal tumors and tumor-like non-neoplastic conditions with CT and MR correlation, including anatomic and imaging clues, and provide a diagnostic approach to aide the radiologist in making a specific diagnosis.

MR imaging in Kallmann syndrome: a case report

BackgroundA rare genetic disorder called Kallmann syndrome results from a defect in the neuronal migration of olfactory axons and gonadotropin-releasing hormone neurons. MR imaging helps in confirming the diagnosis of Kallmann syndrome with characteristic morphological findings in the brain, in clinically suspicious cases of hypogonadotropic hypogonadism with anosmia/hyposmia.Case presentationA 15-year-old male teenager presented with complaints of a small penis and anosmia. Hormonal assay of gonadotropins and testosterone revealed low serum concentrations. MRI brain revealed the absence of the olfactory bulbs in the olfactory grooves and hypoplastic olfactory sulcus. With the gonadotropic hormonal assay showing low levels and characteristic MR imaging features of absent olfactory tracts and olfactory sulcus, the diagnosis of Kallmann syndrome was confirmed.ConclusionsMorphological abnormalities of olfactory tracts and olfactory sulcus can be accurately depicted with MR imaging through anterior fossa in the coronal plane. Therefore, MR imaging of the brain plays a significant role in diagnosing uncommon Kallmann syndrome and other associated brain abnormalities.

Main genetic differences in high-grade gliomas may present different MR imaging and MR spectroscopy correlates.

To assess whether the main genetic differences observed in high-grade gliomas (HGG) will present different MR imaging and MR spectroscopy correlates that could be used to better characterize lesions in the clinical setting. Seventy-nine patients with histologically confirmed HGG were recruited. Immunohistochemistry analyses for isocitrate dehydrogenase gene 1 (IDH1), alpha thalassemia mental retardation X-linked gene (ATRX), Ki-67, and p53 protein expression were performed. Tumour radiological features were examined on MR images. Metabolic profile and infiltrative pattern were assessed with MR spectroscopy. MR features were analysed to identify imaging-molecular associations. The Kaplan-Meier method and the Cox regression model were used to identify survival prognostic factors. In total, 17.7% of the lesions were IDH1-mutated, 8.9% presented ATRX-mutated, 70.9% presented p53 unexpressed, and 22.8% had Ki-67 > 5%. IDH1 wild-type tumours had higher levels of mobile lipids (p = 0.001). The tumour-infiltrative pattern was higher in HGG with unexpressed p53 (p = 0.009). Mutated ATRX tumours presented higher levels of glutamate and glutamine (Glx) (p = 0.001). An association was observed between Glx tumour levels (p = 0.038) and Ki-67 expression (p = 0.008) with the infiltrative pattern. Survival analyses identified IDH1 status, age, and tumour choline levels as independent predictors of prognostic significance. Our results suggest that IDH1-wt tumours are more necrotic than IDH1-mut. And that the presence of an infiltrative pattern in HGG is associated with loss of p53 expression, Ki-67 index, and Glx levels. Finally, tumour choline levels could be used as a predictive factor in survival in addition to the IDH1 status to provide a more accurate prediction of survival in HGG patients. • IDH1-wt tumours present higher levels of mobile lipids than IDH1-mut. • Mutated ATRX tumours exhibit higher levels of glutamate and glutamine. • Loss of p53 expression, Ki-67 expression, and glutamate and glutamine levels may contribute to the presence of an infiltrative pattern in HGG.

Imaging Features of Acute Encephalopathy in Patients with COVID-19: A Case Series.

Coronavirus disease 2019 was declared a global pandemic by the World Health Organization on March 11, 2020. There is a scarcity of data on coronavirus disease 2019-related brain imaging features. We present 5 cases that illustrate varying imaging presentations of acute encephalopathy in patients with coronavirus disease 2019. MR features include leukoencephalopathy, diffusion restriction that involves the GM and WM, microhemorrhages, and leptomeningitis. We believe it is important for radiologists to be familiar with the neuroradiologic imaging spectrum of acute encephalopathy in the coronavirus disease 2019 population.

MRI Findings of Immune Checkpoint Inhibitor-Induced Hypophysitis: Possible Association with Fibrosis.

Hypophysitis is one of the well-known adverse effects of immune checkpoint inhibitors. Immune checkpoint inhibitor-induced hypophysitis frequently causes irreversible hypopituitarism, which requires long-term hormone replacement. Despite the high frequency and clinical significance, characteristic MR imaging findings of immune checkpoint inhibitor-induced hypophysitis have not been established. In the present study, we aimed to review and extract the MR imaging features of immune checkpoint inhibitor-induced hypophysitis. This retrospective international multicenter study comprised 20 patients with melanoma who were being treated with immune checkpoint inhibitors and clinically diagnosed with immune checkpoint inhibitor-induced hypophysitis. Three radiologists evaluated the following MR imaging findings: enlargement of the pituitary gland and stalk; homogeneity of enhancement of the pituitary gland; presence/absence of a well-defined poorly enhanced area and, if present, its location, shape, and signal intensity in T2WI; and enhancement pattern in contrast-enhanced dynamic MR imaging. Clinical symptoms and hormone levels were also recorded. Enlargement of the pituitary gland and stalk was observed in 12 and 20 patients, respectively. Nineteen patients showed poorly enhanced lesions (geographic hypoenhancing lesions) in the anterior lobe, and 11 of these lesions showed hypointensity on T2WI. Thyrotropin deficiency and corticotropin deficiency were observed in 19/20 and 12/17 patients, respectively, which persisted in 12/19 and 10/12 patients, respectively, throughout the study period. Pituitary geographic hypoenhancing lesions in the anterior lobe of the pituitary gland are characteristic and frequent MR imaging findings of immune checkpoint inhibitor-induced hypophysitis. They reflect fibrosis and are useful in distinguishing immune checkpoint inhibitor-induced hypophysitis from other types of hypophysitis/tumors.

Predicting common solid renal tumors using machine learning models of classification of radiologist-assessed magnetic resonance characteristics.

Solid renal masses (SRM) are difficult to differentiate based on standard MR features. The purpose of this study was to assess MR imaging features of SRM to evaluate performance of ensemble methods of classifying SRM subtypes. MR images of SRM (n = 330) were retrospectively evaluated for standard and multiparametric (mp) features. Models of MR features for predicting malignant and benign lesions as well as subtyping SRM were developed using a training dataset and performance was evaluated in a test data-set using recursive partitioning (RP), gradient booting machine (GBM), and random forest (RF) methods. In the test dataset, GBM and RF models demonstrated an accuracy of 86% (95% CI 75% to 93%) for predicting benign versus malignant SRM compared to 83% (95% CI 71% to 91%) for the RP model. RF had the greatest accuracy in predicting SRM subtypes, 81.2% (95% CI 69.5% to 89.9%) compared with GBM 73.4% (95% CI 60.9% to 83.7%) or RP 70.3% (95% CI 57.6% to 81.1%). Marginal homogeneity was reduced by the RF model compared with the RP model (P < 0.001), but not the GBM model (P = 0.135). All models had high sensitivity and specificity for clear cell and papillary renal cell carcinomas (RCC), but performed less well in differentiating chromophobe RCC, oncocytomas, and fat-poor angiomyolipomas. Ensemble methods for prediction of SRM from radiologist-assessed image characteristics have high accuracy for distinguishing benign and malignant lesions. SRM subtype classification is limited by the ability to categorize chromophobe RCCs, oncocytomas, and fat-poor angiomyolipomas.

Radiogenomics correlation between MR imaging features and mRNA-based subtypes in lower-grade glioma

BackgroundTo investigate associations between lower-grade glioma (LGG) mRNA-based subtypes (R1-R4) and MR features.MethodsmRNA-based subtyping was obtained from the LGG dataset in The Cancer Genome Atlas (TCGA). We identified matching patients (n = 145) in The Cancer Imaging Archive (TCIA) who underwent MR imaging. The associations between mRNA-based subtypes and MR features were assessed.ResultsIn the TCGA-LGG dataset, patients with the R2 subtype had the shortest median OS months (P < 0.05). The time-dependent ROC for the R2 subtype was 0.78 for survival at 12 months, 0.76 for survival at 24 months, and 0.76 for survival at 36 months. In the TCIA-LGG dataset, 41 (23.7%) R1 subtype, 40 (23.1%) R2 subtype, 19 (11.0%) R3 subtype and 45 (26.0%) R4 subtype cases were identified. Multivariate analysis revealed that enhancing margin (ill-defined, OR: 9.985; P = 0.003) and T1 + C/T2 mismatch (yes, OR: 0.091; P = 0.023) were associated with the R1 subtype (AUC: 0.708). The average accuracy of the ten-fold cross validation was 71%. Proportion of contrast-enhanced (CE) tumour (> 5%, OR: 14.733; P < 0.001) and necrosis/cystic changes (yes, OR: 0.252; P = 0.009) were associated with the R2 subtype (AUC: 0.832). The average accuracy of the ten-fold cross validation was 82%. Haemorrhage (yes, OR: 8.55; P < 0.001) was positively associated with the R3 subtype (AUC: 0.689). The average accuracy of the ten-fold cross validation was 87%. Proportion of CE tumour (> 5%, OR: 0.14; P < 0.001) was negatively associated with the R4 subtype (AUC: 0.672). The average accuracy of the ten-fold cross validation was 71%. For the prediction of the R2 subtype, the nomogram showed good discrimination and calibration. Decision curve analysis demonstrated that prediction with the R2 model was clinically useful.ConclusionsPatients with the R2 subtype had the worst prognosis. We demonstrated that MRI features can identify distinct LGG mRNA-based molecular subtypes.

Mechanical strength characteristics of fiber-reinforced pond ash for pavement application

The pavement construction sector throughout the world is facing a major challenge of non-availability of suitable construction materials. On the other side, many waste/sub-products are being generated from manufacturing/production units causing environmental pollution. One of such waste materials is pond ash produced from thermal electric power plants, which can be utilized as an alternative construction material in place of traditional materials. In this context, an attempt was made on fiber-reinforced pond ash as subbase layer of flexible pavements to understand its engineering behavior by conducting static (California bearing ratio, CBR) and dynamic (repeated load triaxial, RLT) tests. Randomly distributed polypropylene fibers of various proportions were used in pond ash as reinforcement inclusions. The test results were analyzed to address the influence of fiber on conventional parameters of pond ash such as CBR, resilient modulus (MR), and permanent strain (ϵp). Also, the influence of confining (σc) and deviatoric stress (σd) levels on MR as well as ϵp with load cycles have been investigated for both unreinforced and reinforced pond ash. The results obtained have shown that the inclusion of fiber improves the CBR, MR and ϵp characteristics of the pond ash. With an increase in stress levels (σc and σd), the MR of reinforced pond ash increased compared to non-reinforced ash. Irrespective of the fiber content in pond ash, permanent strain values were increased with an increase in the number of loading cycles and cyclic deviatoric stresses. However, with the introduction of fiber, the rate of strain development in pond ash was reduced significantly. Furthermore, the experimentally obtained MR and ϵp values were validated against existing models established by previous researchers. From the above findings, it can be concluded that fiber-reinforced pond ash can be used effectively in pavement layer applications.

MRI features predict microvascular invasion in intrahepatic cholangiocarcinoma

BackgroundThe presence of microvascular invasion (MVI) in intrahepatic cholangiocarcinoma (ICC) is a significant adverse prognostic factor. This study sought to investigate the correlation between preoperative imaging parameters and MVI in ICC.MethodsA total of 108 patients with surgically resected single ICC tumors (34 MVI-positive and 74 MVI-negative lesions) who underwent MRI examination, including T1WI, T2WI, DWI, and dynamic enhancement imaging, were enrolled in this retrospective study. The following qualitative and quantitative characteristics were evaluated: tumor morphology, signal features on T1WI and T2WI, intrahepatic duct dilatation, hepatic capsule retraction, target sign on DWI, dynamic enhancement pattern, arterial phase enhancement pattern, dot−/band-like enhancement inside the tumor, visible vessel penetration inside the tumor (hepatic artery, portal vein, or hepatic vein), integrity of the enhancement edge of the arterial phase, peripheral hepatic enhancement, tumor size, maximum enhancement edge thickness, arterial edge enhancement ratio, and delayed phase enhancement ratio. Other clinicopathological features were also used to predict and evaluate MVI in ICC. Chi-square test, Fisher’s exact test, and independent t-test were used for univariate analysis to determine the relationships among the presence of MVI and these MR parameters. Logistic regression analysis was used to identify predictors of MVI among these MR parameters.ResultsAmong MRI characteristics, tumor morphology, intrahepatic duct dilatation, arterial phase enhancement pattern, visible hepatic artery penetration sign, maximum diameter of the tumor and the arterial phase edge enhancement ratio were correlated with MVI (P = 0.007, 0.003, 0.008, 0.000, 0.003, and 0.002, respectively). Furthermore, higher CA19–9 levels (≥37 U/ml) and pathological tumor grade III were also related to MVI (P = 0.014 and 0.004, respectively). However, multivariate logistic regression analysis demonstrated that none of the parameters were independent risk factors for the diagnosis of MVI in ICCs.ConclusionFor the preoperative prediction of MVI in ICC, six qualitative and quantitative data obtained on preoperative MRI, as well as one tumorigenic marker and the pathological tumor grade, were statistically significant. More research is needed to identify MR characteristics that can be used as independent risk factors.

Clinical Manifestations and Radiological Characteristics on Rosai-Dorfman Disease: A Retrospective Observational Study

Background and Objective: Rosai-Dorfman disease (RDD) are usually misdiagnosed because of rarity and nonspecific clinical and radiological features. The aim of our study is to explore the clinical and imaging characteristics of RDD to improve diagnostic accuracy. Methods: Clinical and imaging data in 10 patients with RDD were retrospectively analyzed. 7 patients were underwent CT scanning and 3 patients were underwent MR examination. Results: 8 (8/10) patients presented with painless enlarged lymph nodes (LNs) or mass. 3 cases were involved with LNs, 5 cases were involved with extra-nodal tissues, and the remaining 2 cases were involved with LNs and extra-nodal tissue simultaneously. In enhanced CT images, enlarged LNs displayed mild or moderate enhancement, and 2 cases showed heterogeneous ring-enhancement. MR features of 3 patients with extra-nodal RDD, 2 cases showed a mass located in the subcutaneous and anterior abdominal wall respectively, and 1 case showed an intracranial mass. Besides, all lesions showed high signal foci on DWI images, and were characterized by marked heterogeneous enhancement with blurred edge. The dural/fascia tail sign and dilated blood vessels could be seen around all the lesions on enhanced MRI. Radiological features of 2 cases with LN and extranodal tissue involved, one case presented with the swelling and thickening of pharyngeal lymphoid ring and nasopharynx, meanwhile with enlarged LNs in bilateral submandibular area, neck and abdominal cavity, and also companied with osteolytic lesion in right proximal humerus. All these LNs displayed mild and moderate enhancement on CT images. Another case showed enlarged LNs in bilateral neck accompanied with soft tissue mass in the sinuses. Conclusions: RDD occurred commonly in young and middle-aged men and presented with painless enlarged LNs or mass.RDD had a huge diversity of imaging findings, which varied with different location. The radiological features, such as small patches of high signal foci in the masses on DWI images, heterogeneous enhancement and blood vessels around the masses, are helpful in diagnosis of extranodal RDD.

Conventional MR and DW imaging findings of cerebellar primary CNS lymphoma: comparison with high-grade glioma

Primary central nervous system lymphomas (PCNSLs) and high-grade gliomas (HGGs) arising in the cerebellum is extremely low, making the differential diagnosis difficult or even impossible. The purpose of this study was to define the MR features of cerebellar PCNSL in immunocompetent patients, and to determine whether a combination of conventional MR and DW imaging can assist in the differentiation of PCNSLs and HGGs. Twelve PCNSLs and 15 HGGs confirmed by pathological analysis were retrospectively identified. The apparent diffusion coefficient (ADC) and conventional MRI parameters were compared for differences between PCNSL and HGG groups using the independent sample t test or chi-square test. Both ADCmin and ADCtotal values were lower in the PCNSL group than those in the HGG group (ADCmin: 0.53 × 10−3 vs. 0.83 × 10−3 mm2/sec, P < 0.001; ADCtotal: 0.66 × 10−3 vs. 0.98 × 10−3 mm2/sec, P = 0.001). As for conventional MR features, there were significant difference in the tumor size, enhancement patterns, the presence of cystic changes, edema degree and streak-like edema (all P < 0.01); but there were no significant difference in lesion type, the presence of bleeding, and involvement of brain surface between two groups (P = 0.554, 0.657 and 0.157, respectively). The results revealed that several conventional MR features, including enhancement patterns, branch-like enhancement and streak-like edema may be useful for the differentiation of PCNSL and HGG in cerebellum and, when combined with ADC values, further improve the discriminating ability.