Nonenhanced Magnetic Resonance Research Articles

Association between lymphatic abnormalities in the neck and thorax in primary chylopericardium and surgical outcomes evaluated by non-enhanced magnetic resonance (MR) lymphangiography.

Chylopericardium refers to the accumulation of chylous fluid in the pericardial cavity. Non-enhanced magnetic resonance lymphangiography (MRL) can show neck and thoracic lymphatic abnormalities in the primary chylopericardium. It is not clear whether there is a relationship between neck and thoracic lymphatic abnormalities in primary chylopericardium and thoracic duct terminal release surgery. This study aimed to explore the correlation between the severity of neck and thoracic lymphatic abnormalities observed in non-enhanced MRL and the surgical outcomes in primary chylopericardium. This is a retrospective cohort study. A retrospective analysis was conducted on fifty-six patients diagnosed with primary chylopericardium between January 2016 and December 2021, all of whom underwent thoracic duct terminal release surgery. Ultrasonography, chest computed tomography (CT) and non-enhanced MRL were performed prior to the surgical intervention. Patients were categorized into four types based on the severity of neck and thoracic lymphatic abnormalities observed in the non-enhanced MRL. Clinical and laboratory examinations and surgical outcomes were compared across different types using χ 2-test or Fisher's exact test, t-test, and Kruskal-Wallis H-test. Additionally, independent factors influencing surgical outcomes were analyzed. Among primary chylopericardium cases (n=56), 22 (39.2%) were classified as type I or II, 17 (30.4%) as type III, and 17 (30.4%) as type IV. Surgical outcomes were more favorable for type I or II patients than those with type III or IV, accompanied by a reduction in postoperative primary chylopericardium volume (P=0.002). Postoperative chest CT scans indicated that type I or II patients had fewer instances of large grid shadows, small grid shadows, and bronchovascular bundle thickening compared to preoperative scans (P=0.001, P=0.02, P=0.03). Age and bronchomediastinal trunk dilation emerged as independent factors influencing surgical outcomes [odds ratio (OR) 0.03, 95% confidence interval (CI): 0.003-0.220, P=0.001; OR 11.10, 95% CI: 1.70-72.39, P=0.01, respectively]. A more severe degree of neck and thoracic lymphatic abnormalities is associated with worse surgical outcomes. Moreover, age and bronchomediastinal trunk dilatation are independent predictors of surgical outcomes. Preoperative utilization of non-enhanced MRL for severity of lymphatic abnormalities classification in primary chylopericardium patients offers a noninvasive means of assessing surgical risk.

A comparison of conventional 3.0-Tesla nonenhanced magnetic resonance imaging and arthroscopic findings of the anteroinferior capsulolabral complex in patients with traumatic anterior shoulder instability

This study aimed to evaluate the association between specific, reproducible findings of an anteroinferior capsulolabral complex obtained using conventional 3.0-Tesla nonenhanced magnetic resonance imaging (MRI) and pathologic arthroscopic findings and to assess the confidence level of the findings. Of 125 cases of traumatic anterior instability surgery from January 2017 to November 2019, 66 patients (52 men, 14 women; 23.5±7.9 year old) who underwent conventional 3.0-Tesla MRI at our hospital were reviewed. The following anteroinferior capsulolabral complex features were observed on the T2-star axial image: size difference of the labrum (swelling, diminished), difference in marginal and internal signals (irregularity), and capsule edema image (capsular thickening). We also reviewed fraying, flattening, cracking, and capsular hypertrophy as pathologic arthroscopic findings of the capsulolabral complex. These findings allowed for the simultaneous description of the MRI and arthroscopic evaluations. Three orthopedic surgeons and one radiologist measured the interobserver reliability. We investigated the correlation between the MRI and arthroscopic findings. The interobserver reliability of MRI irregularities was low (κ=-0.16), whereas reliability was moderate (κ=0.554-0.595) for swelling in 22 cases (33%), diminished in 34 cases (52%), and capsular thickness in 40 cases (59%). Labral detachment was found in 26 patients (39%) and fluid collection in 24 patients (36%). The agreement of MRI findings with arthroscopic findings was κ=0.46 (95% confidence interval [CI]: 0.268-0.654) for swelling to fraying; κ=0.42 (95% CI: 0.202-0.638) for swelling to capsular hypertrophy; and 0.46 (95% CI: 0.268-0.654) for flattening to diminished. The swelling and diminished findings of the anteroinferior capsulolabral complex on conventional MRI were moderately related to pathologic arthroscopic findings in patients with traumatic anterior shoulder instability. These findings contribute to achieving an accurate clinical diagnosis.

The value of the dermal rim sign on nonenhanced magnetic resonance imaging for predicting dermal backflow in patients with primary lower extremity lymphedema

PurposeThe dermal rim sign (DRS) on nonenhanced magnetic resonance imaging has been shown to predict dermal backflow (DBF) in patients with secondary upper limb lymphedema. However, whether the DRS has the same effects on primary lower extremity lymphedema (PLEL) has not been clearly reported. Therefore, this study aimed to explore whether the DRS can be used to diagnose DBF on lymphoscintigraphy in patients with PLEL. MethodsA total of 94 patients who were diagnosed with PLEL were recruited for this retrospective study from January 2022 to December 2023. All the patients were divided into two groups according to the lymphoscintigraphy findings: no DBF and DBF. The magnetic resonance imaging data of the two groups were recorded and statistically compared for the following indicators: range of lymphedema involvement (left, right, whole lower limbs, only thigh, only calf and ankle), signs of lymphedema (notable thickening of skin, parallel line sign, grid sign, honeycomb sign, band sign, lymph lake sign, crescent sign, DRS), and lymphedema measurement (skin thickness, band width). The DRS is characterized by notable thickening of the skin plus the grid sign and/or honeycomb sign, plus the band sign. ResultsThe following statistically significant differences in the following indicators were found between the two groups (P < .05): notable skin thickening, parallel line sign, grid sign, honeycomb sign, band sign, DRS, skin thickness, and band width. The sensitivity, specificity, and accuracy for predicting for DBF with the DRS was 82%, 64%, and 77%, respectively. ConclusionsThis study confirmed good consistency between the DRS and DBF from the perspective of imaging. This tool is suitable for children, adolescents, and patients with contraindications to lymphoscintigraphy. The DRS has important value in assessing the severity of PLEL. The DRS is suggested for the clinical use of combined surgical treatment of PLEL.

Differentiating gallbladder cancer from polyps using non-enhanced magnetic resonance imaging.

This retrospective cohort study assessed the efficiency of non-enhanced magnetic resonance imaging (MRI) for differentiating gallbladder cancer (GBC) from gallbladder polyps (GBPs) measuring ≥ 10 mm. Patients diagnosed with GBCs or GBPs ≥ 10 mm and GBC ≤ T2 stage were eligible for inclusion. Two independent blinded readers assessed the continuity of the mucosal and muscular layers (CMML; present or absent) and normalised signal intensity ratio (NIR) on the apparent diffusion coefficient map (NIR-ADC), T1-weighted image (NIR-T1WI), and T2-weighted half-Fourier acquisition single-shot turbo spin-echo image. Univariate and multivariate logistic regression analyses and interobserver agreement analyses were performed to detect predictive variables differentiating GBCs from GBPs. Receiver operating characteristic (ROC) analysis was performed to evaluate diagnostic performance. A reproducibility test was performed to verify the predictive variables. Multivariate analysis showed significant differences in CMML, NIR-ADC, and NIR-T1WI (p < 0.001). The positive predictive value (PPV) and specificity of the absence of CMML were approximately 100%. The CMML showed the best specificity, accuracy, and PPV in the reproducibility study. The sensitivity of CMML alone was approximately 50%, whereas it increased to approximately 70% when combined with NIR-ADC. The diagnostic performance of the combination, including sensitivity, was almost like that of tumour size. The combined tumour size and CMML assessment showed higher diagnostic performance than tumour size alone. The absence of CMML and NIR-ADC ≤ 1.86 helped in differentiating GBCs from GBPs. Evaluation of the absence of CMML and measurement of tumour size could better aid in determining between the two than measurement of tumour size alone.

Noninvasive prediction of insufficient biochemical response after ursodeoxycholic acid treatment in patients with primary biliary cholangitis based on pretreatment nonenhanced MRI

ObjectivesTo explore the feasibility of pretreatment nonenhanced magnetic resonance imaging (MRI) in predicting insufficient biochemical response to ursodeoxycholic acid (UDCA) in patients with primary biliary cholangitis (PBC).MethodsFrom January 2009 to April 2022, consecutive PBC patients who were treated with UDCA and underwent nonenhanced MRI within 30 days before treatment were retrospectively enrolled. All MR images were independently evaluated by two blinded radiologists. Uni- and multivariable logistic regression analyses were performed to develop a predictive model for 12-month insufficient biochemical response. Model performances were evaluated by computing the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity.ResultsA total of 74 patients (50.6 ± 11.9 years; 62 females) were included. Three pretreatment MRI features, including hepatomegaly (odds ratio [OR]: 4.580; p = 0.011), periportal hyperintensity on T2-weighted imaging (T2WI) (OR: 4.795, p = 0.008), and narrowing of the bile ducts (OR: 3.491; p = 0.027) were associated with 12-month insufficient biochemical response in the multivariable analysis. A predictive model based on the above indicators had an AUC of 0.781, sensitivity of 85.4%, and specificity of 61.5% for predicting insufficient biochemical response.ConclusionsA noninvasive model based on three pretreatment MRI features could accurately predict 12-month insufficient biochemical response to UDCA in patients with PBC. Early identification of PBC patients at increased risk for insufficient response can facilitate the timely initiation of additional treatment.Clinical relevance statementA noninvasive predictive model constructed by incorporating three pretreatment MRI features may help identify patients with primary biliary cholangitis at high risk of insufficient biochemical response to ursodeoxycholic acid and facilitate the timely initiation of additional treatment.Key Points• Noninvasive imaging features based on nonenhanced pretreatment MRI may predict an insufficient biochemical response to UDCA in PBC patients.• A combined model based on three MRI features (hepatomegaly, periportal hyperintensity on T2-weighted imaging, and narrowing of the bile ducts) further improved the predictive efficacy for an insufficient biochemical response to UDCA in PBC patients, with high sensitivity and specificity.• The nomogram of the combined model showed good calibration and predictive efficacy for an insufficient biochemical response to UDCA in PBC patients. In particular, the calibration curve visualised the clinical applicability of the prediction model.

Radiomics Features in Contrast‐Enhanced and Nonenhanced Magnetic Resonance Imaging Images Are Associated With High Intracranial Aneurysmal Risk

Background Aneurysm wall enhancement is a potential imaging biomarker for risk stratification of intracranial aneurysms (IAs). Variations in the texture of the magnetic resonance imaging (MRI) signal could shed light on the underlying pathobiology of the aneurysm wall. Radiomics can help quantify the textural complexity in MRI images, which could lead to better understanding and risk stratification of IAs. Herein, we investigated the potential use of radiomics derived from nonenhanced and contrast‐enhanced MRI to identify high‐risk IAs and evaluated their performance on different data sets. Methods We obtained 126 IAs from different centers and extracted radiomics features from nonenhanced and contrast‐enhanced MRI for each aneurysm. We then built a random forest model from a part of the 3‐T data set to identify high‐risk IAs based on the 5‐year population, hypertension, age, size of aneurysm, earlier SAH from another aneurysm, site of aneurysm (PHASES) score. We then tested the performance of this model on a part of the same 3‐T data set, a 7‐T data set, and an external 3‐T data set. We also performed multivariate analysis to understand the significance of radiomics features. Results We found that 75 radiomics features were significantly different between high‐ and low‐risk IAs. The radiomics model had good performance when tested on the 3‐T data set (accuracy, 90%; sensitivity, 86%; and specificity, 92%); however, when tested on external data sets, it had a moderate performance (accuracy, 88%; sensitivity, 50%; and specificity, 95% for external 3‐T data set; and accuracy, 62%; sensitivity, 27%; and specificity, 100% for 7‐T data set). Conclusions Radiomics derived from nonenhanced and contrast‐enhanced MRI show high accuracy in identifying high‐risk aneurysms from the same data set and could be used as a tool for quantifying aneurysm wall enhancement.

Heuristic multi-modal integration framework for liver tumor detection from multi-modal non-enhanced MRIs

The detection of liver tumors from non-enhanced Magnetic Resonance Imaging (MRI) has become crucial for current diagnosis and treatment due to the avoidance of contrast-agent injection and associated health risks. A recent study, based on Deep Reinforcement Learning (DRL), validated the feasibility of detecting liver tumors from non-enhanced MRIs for the first time. However, this study only employed single-modal MRIs, where malignant tumors are often invisible, leading to the detection of only benign tumors. This paper proposes the Heuristic Multi-modal Integration (HMI) framework to detect both benign and malignant tumors from multi-modal non-enhanced MRIs. The HMI utilizes individual DRL modules on each modality to extract specific features and then integrates these modules into a collective DRL module, utilizing the comprehensive information from multiple modalities to detect the desired tumors. Compared to existing liver tumor detection methods, the HMI is the first study without contrast agents in both training and testing, expanding the reach of non-enhanced detection technology. Furthermore, the HMI successfully employs DRL in a multi-modal environment, offering a solution to the difficulties of DRL convergence with complex inputs and high computational requirements. The experimental results show that the HMI outperforms current state-of-the-art methods, making it an accurate and contrast-agent-free alternative for liver tumor detection in clinical settings.

Non-enhanced magnetic resonance imaging-based radiomics model for the differentiation of pancreatic adenosquamous carcinoma from pancreatic ductal adenocarcinoma.

To evaluate the diagnostic performance of radiomics model based on fully automatic segmentation of pancreatic tumors from non-enhanced magnetic resonance imaging (MRI) for differentiating pancreatic adenosquamous carcinoma (PASC) from pancreatic ductal adenocarcinoma (PDAC). In this retrospective study, patients with surgically resected histopathologically confirmed PASC and PDAC who underwent MRI scans between January 2011 and December 2020 were included in the study. Multivariable logistic regression analysis was conducted to develop a clinical and radiomics model based on non-enhanced T1-weighted and T2-weighted images. The model performances were determined based on their discrimination and clinical utility. Kaplan-Meier and log-rank tests were used for survival analysis. A total of 510 consecutive patients including 387 patients (age: 61 ± 9 years; range: 28-86 years; 250 males) with PDAC and 123 patients (age: 62 ± 10 years; range: 36-84 years; 78 males) with PASC were included in the study. All patients were split into training (n=382) and validation (n=128) sets according to time. The radiomics model showed good discrimination in the validation (AUC, 0.87) set and outperformed the MRI model (validation set AUC, 0.80) and the ring-enhancement (validation set AUC, 0.74). The radiomics model based on non-enhanced MRI outperformed the MRI model and ring-enhancement to differentiate PASC from PDAC; it can, thus, provide important information for decision-making towards precise management and treatment of PASC.

Detection of cerebral aneurysm and intracranial vertebral dissection using non-enhanced magnetic resonance imaging in emergency setting: Emphasis on magnitude image of susceptibility-weighted image.

To evaluate image features and diagnostic performance of susceptibility-weighted image (SWI) in detection of intracranial vertebral artery dissection (VAD) and unruptured intracranial aneurysm (UIA). From January 2015 to December 2021, symptomatic patients who underwent 3.0 T MR SWI were recruited. For study group, transfemoral cerebral angiography-proven lesions were included, while 1:1 matched control group with MR angiography were included. Image features of SWI were evaluated. Diagnostic performance and interobserver agreements were calculated for detecting VAD with stenosis and UIA greater than 7 mm. Total of 110 patients (mean age: 60.92 years, female: 60/110) were included. In the study group (N = 55), 21 patients (38.2%) had VAD, while 34 patients (61.8%) had UIA. For SWI-detectable VAD, larger parent artery (PA)-dilatation ratio was observed (1.36 vs. 1.84, p = 0.034). For SWI-detectable UIA, larger PA-dome ratio (1.32 vs. 1.90, p = 0.020) and larger PA-height ratio (1.25 vs. 1.77, p = 0.005) were observed. The diagnostic performance and kappa values for VAD with stenosis were as follow: sensitivity: 91.7 (95% CI: 61.5-99.8); specificity: 93.9 (95% CI: 87.2-97.7); к: 0.80. The diagnostic performance for UIA larger than 7 mm were as follow: sensitivity: 87.5 (95% CI: 47.4-99.7); specificity: 95.1 (95% CI: 88.9-98.4); к: 0.73. SWI-detectable lesions were VAD with larger PA-dilatation ratio, and UIA with larger PA-dome ratio, and PA-height ratio. SWI was able to accurately detect VAD with stenosis and UIA larger than 7 mm with substantial interobserver agreements.

Correlation between renal ablation zone in contrast-enhanced CT and non-enhanced MRI during the early period following percutaneous cryoablation

PurposeTo retrospectively evaluate and correlate the contrast-enhanced computed tomography (CECT) and non-enhanced magnetic resonance imaging (MRI) during the early period following renal cryoablation.Materials and methodsBoth dynamic CECT and non-enhanced MRI were performed within 4 days following cryoablation in 34 renal tumors in 33 patients. The renal volumes of the unenhanced regions on dynamic CECT (nephrogenic phase, 4 mm thickness) and the regions with signal intensity changes on non-enhanced MRI (fat-suppressed T2-weighted image, 4 mm thickness) were evaluated. Fusion images of the axial, coronal, and sagittal sections of CECT and MRI images were created from the maximum cross-section of the renal tumor, and the match score of each image was visually evaluated on a 5-point scale.ResultsThe mean renal volume of the unenhanced regions on CECT and those with signal intensity changes on non-enhanced MRI following cryoablation were 29.5 ± 19.9 cm3 (range, 4.3–97.4 cm3) and 30.7 ± 19.8 cm3 (range, 6.7–94.0 cm3), respectively; the difference between them was –1.17 cm3 (95% confidence interval [CI] –2.74, 0.40, P = 0.139). The Pearson’s product-moment correlation coefficient (r = 0.975; 95% CI, 0.951, 0.988; P < 0.0001) showed a strong correlation between the volumes. The average match score between CECT and non-enhanced MRI was as high as 4.5 ± 0.5 points (radiologist 1, 4.3 ± 0.5; radiologist 2, 4.7 ± 0.5). Local tumor control rate was 94.1% (32/34 tumors) and recurrence-free survival rate was 82.0% (95% CI: 64.2%, 91.5%) at 5 years.ConclusionsThe region with signal intensity changes on non-enhanced MRI was strongly correlated with the unenhanced region on CECT during the early period following renal cryoablation.

Abbreviated non-enhanced magnetic resonance imaging in patients with acute necrotizing pancreatitis.

To investigate the performance of T2-weighted abbreviated magnetic resonance imaging (T2W-AMRI) protocol in evaluating patients with acute necrotizing pancreatitis (ANP). A retrospective analysis of consecutive hospitalized patients with ANP who underwent MRI (contrast-enhanced, CE or non-contrast, NC) between January 2017 and November 2020was performed. The T2W-AMRI and complete MRI (cMRI) sequences were anonymized, and subsequently, two separate sets of data (AMRI and cMRI) were created for presentation to the radiologists involved in reading the data. The T2W-AMRI was based on a single-axial T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence. The pancreatic and extrapancreatic findings were recorded and tabulated independently by two radiologists on T2W-AMRI and cMRI. In addition, the interobserver agreement and association of findings between T2W-AMRI and cMRI were analyzed. Twenty-eight patients (mean age 31.7 ± 12.2years, 17 females) were included. Thirteen patients had CE-cMRI, while the rest underwent NC-cMRI. There was no significant difference in the identification of pancreatic necrosis on T2W-AMRI vs. cMRI (p = 1.00). However, T2W-AMRI underestimated necrosis in one patient. Collections were accurately detected in all patients on T2W-AMRI. The mean size of the collection was larger on cMRI (6.5 ± 3.7cm) than T2W-AMRI (6 ± 3.7cm) with p = 0.006. cMRI detected more patients with disrupted pancreatic duct (n = 9) than T2W-AMRI (n = 6). However, the difference was not statistically significant (p = 0.375). There was a good to an excellent interobserver agreement between the readers for T2W-AMRI (k = 0.62-1). T2W-AMRI may offer a suitable alternative to cMRI in ANP, especially severe disease, as it can be acquired rapidly without the need for contrast injection.

Transvaginal Aspiration for Management of Huge Ovarian Endometrioma in Pregnancy

Study Objective To demonstrate a minimally invasive approach of a huge ovarian cyst during pregnancy. Design A step-by-step explanation of the patient's condition, diagnosis, surgical technique, and post-operative results. Setting The patient underwent transvaginal procedure in the lithotomy position and under intravenous sedation and ventilation by face mask. Patients or Participants A 34-year-old woman, gravida 1 at 12 weeks 5 days’ gestation, presented with huge ovarian cyst. A transvaginal ultrasound demonstrated ovarian cyst measuring 10.4 × 8.2 cm with no evidence of malignancy, no free fluid, and a normal-appearing contralateral ovary. The crown-rump length measured 5.92 cm. On non-enhanced magnetic resonance imaging (MRI), 11 × 7 cm sized cystic lesion with high signal intensity in T1-weighted image (WI) and T1-weighted fat suppressed image, low signal intensity in T2 WI suggesting endometrioma, located in cul-de-sac was noted. Because the cyst was huge and deeply located in cul-de-sac, and the uterus was enlarged to 13 weeks size, approach through laparoscopy or even laparotomy was thought to be difficult and the risk of manipulation for uterus was high. So, we decided to aspirate the ovarian cyst through the vaginal route. Interventions Ultrasound-guided transvaginal aspiration was performed using an 18-G needle. Measurements and Main Results The operation time was 4 hours and 35 minutes with 305 mL dark brownish fluid drained. The patient recovered well and was discharged 2days after the procedure. There was no intraoperative or postoperative complication. Postoperative ultrasound revealed neither recurrence nor fetal abnormality. Until delivery, the patient was free of symptom and ultrasound revealed neither recurrence nor fetal abnormality. Conclusion In select pregnant woman with endometrioma requiringintervention, the risks of surgery may be minimized with aspiration. Transvaginal ultrasound-guided aspiration is a safe, feasible, and effective minimally invasive procedure for huge ovarian endometrioma in pregnancy. To demonstrate a minimally invasive approach of a huge ovarian cyst during pregnancy. A step-by-step explanation of the patient's condition, diagnosis, surgical technique, and post-operative results. The patient underwent transvaginal procedure in the lithotomy position and under intravenous sedation and ventilation by face mask. A 34-year-old woman, gravida 1 at 12 weeks 5 days’ gestation, presented with huge ovarian cyst. A transvaginal ultrasound demonstrated ovarian cyst measuring 10.4 × 8.2 cm with no evidence of malignancy, no free fluid, and a normal-appearing contralateral ovary. The crown-rump length measured 5.92 cm. On non-enhanced magnetic resonance imaging (MRI), 11 × 7 cm sized cystic lesion with high signal intensity in T1-weighted image (WI) and T1-weighted fat suppressed image, low signal intensity in T2 WI suggesting endometrioma, located in cul-de-sac was noted. Because the cyst was huge and deeply located in cul-de-sac, and the uterus was enlarged to 13 weeks size, approach through laparoscopy or even laparotomy was thought to be difficult and the risk of manipulation for uterus was high. So, we decided to aspirate the ovarian cyst through the vaginal route. Ultrasound-guided transvaginal aspiration was performed using an 18-G needle. The operation time was 4 hours and 35 minutes with 305 mL dark brownish fluid drained. The patient recovered well and was discharged 2days after the procedure. There was no intraoperative or postoperative complication. Postoperative ultrasound revealed neither recurrence nor fetal abnormality. Until delivery, the patient was free of symptom and ultrasound revealed neither recurrence nor fetal abnormality. In select pregnant woman with endometrioma requiringintervention, the risks of surgery may be minimized with aspiration. Transvaginal ultrasound-guided aspiration is a safe, feasible, and effective minimally invasive procedure for huge ovarian endometrioma in pregnancy.

Improving Automated Glioma Segmentation in Routine Clinical Use Through Artificial Intelligence-Based Replacement of Missing Sequences With Synthetic Magnetic Resonance Imaging Scans.

Although automated glioma segmentation holds promise for objective assessment of tumor biology and response, its routine clinical use is impaired by missing sequences, for example, due to motion artifacts. The aim of our study was to develop and validate a generative adversarial network for synthesizing missing sequences to allow for a robust automated segmentation. Our model was trained on data from The Cancer Imaging Archive (n = 238 WHO II-IV gliomas) to synthesize either missing FLAIR, T2-weighted, T1-weighted (T1w), or contrast-enhanced T1w images from available sequences, using a novel tumor-targeting loss to improve synthesis of tumor areas. We validated performance in a test set from both the REMBRANDT repository and our local institution (n = 68 WHO II-IV gliomas), using qualitative image appearance metrics, but also segmentation performance with state-of-the-art segmentation models. Segmentation of synthetic images was compared with 2 commonly used strategies for handling missing input data, entering a blank mask or copying an existing sequence. Across tumor areas and missing sequences, synthetic images generally outperformed both conventional approaches, in particular when FLAIR was missing. Here, for edema and whole tumor segmentation, we improved the Dice score, a common metric for evaluation of segmentation performance, by 12% and 11%, respectively, over the best conventional method. No method was able to reliably replace missing contrast-enhanced T1w images. Replacing missing nonenhanced magnetic resonance sequences via synthetic images significantly improves segmentation quality over most conventional approaches. This model is freely available and facilitates more widespread use of automated segmentation in routine clinical use, where missing sequences are common.

Non-enhanced multimodal magnetic resonance imaging in assessment of iliac vein obstruction with or without thrombosis.

To evaluate the diagnostic accuracy of a contrast-free multimodal magnetic resonance (MR) protocol (including M2DIPEAR, THRIVE, BTFE-SPAIR, and FLAIR sequences) in the detection of iliac vein obstruction with or without thrombosis. From May 1st, 2015, to May 1st, 2016, a total of 73 patients (aged 51.33 ± 4.21 years) who received both digital subtraction angiography (DSA) and the multimodal MR imaging were included. The protocol of the multimodal MR included M2DIPEAR and BTFE-SPAIR for presenting iliac vein obstruction, and THRIVE and FLAIR for revealing the co-existed thrombosis. Three observers who were blinded to clinical and DSA results independently analyzed all multimodal MR datasets. Per-patient evaluations on presence or absence of iliac vein obstruction were performed to calculate the diagnostic performance of MR imaging (DSA regarded as gold reference) in terms of overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Capability to display the co-existing venous thrombus was also evaluated per-MR sequence using a 3-point scale system. Iliac vein obstruction was depicted with DSA in 64 patients. In per-patient evaluation, the multimodal MR imaging yielded accuracy of 95.9% (70/73), sensitivity of 96.9% (62/64), specificity of 88.9% (8/9), positive predictive value of 98.4% (62/63), and negative predictive value of 80% (8/10), respectively. In the multimodal MR sequences, balanced turbo field echo-spectral attenuated inversion recovery (BTFE-SPAIR) sequence was superior to other sequences in depicting the iliac vein configuration, but fluid attenuated inversion recovery (FLAIR) and T1 high-resolution isovolumetric examination (THRIVE) seemed superior in detecting co-existing venous thrombosis. M2DIPEAR and BTFE-SPAIR sequence can reveal iliac vein obstruction while THRIVE and FLAIR can detect the co-existed thrombosis. The proposed multimodal MR protocol can accurately depict the iliac vein obstruction and accurately detect the co-existing venous thrombosis comparable with that of DSA.

A Correlative Study Between IVIM-DWI Parameters and the Expression Levels of Ang-2 and TKT in Hepatocellular Carcinoma.

BackgroundNoninvasive evaluation of the expression of angiopoietin-2 (Ang-2) and transketolase (TKT) in hepatocellular carcinoma (HCC) is of great significance for the clinical development of individualized treatment plans. However, the correlation between intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and the expression of Ang-2 and TKT has not been reported. We sought to investigate the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs.MethodsConventional non-enhanced magnetic resonance imaging (MRI) and IVIM-DWI and dynamic contrast MRI were performed for 61 patients with HCC before surgical treatment. Various IVIM-DWI parameters, such as apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*) and fraction of fast apparent diffusion coefficient (f), were calculated using Function-MADC software. Expression levels of Ang-2 and TKT in HCC were detected via immunohistochemical staining and classified into two grades. Independent sample t tests were used to compare differences in parameters between the two groups. The Spearman rank correlation test was used to analyze the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs.ResultsThe D* and f values were significantly higher in the high Ang-2 group than in the low Ang-2 group; there were no obvious between-group differences in ADC and D. Ang-2 expression was positively correlated with D* and f but not with ADC and D. The ADC and D values were significantly lower in the high TKT group than in the low TKT group, whereas the between-group differences for D* and f were not significant. TKT expression was negatively correlated with ADC and D but not with D* and f.ConclusionsIVIM-DWI can be used to evaluate Ang-2 and TKT expression in HCC.

Second Look Ultrasonography-Guided Breast Biopsy with Magnetic Resonance Imaging Confirmation by Intralesional Contrast Injection.

This study aimed to introduce an alternative pre-biopsy confirmation technique that combines sonography-guided intra-lesional contrast injections and single non-enhanced magnetic resonance imaging (MRI) pulse sequence in order to identify sonographic correlates of incidentally detected breast MRI lesions which were occult on primary ultrasonography (USG) and mammography examination. From May 2014 through May 2015, a total of 37 incidental breast lesions of 37 patients, which were detected by breast MRI, were evaluated with targeted second look ultrasound (SLUS). The suspected lesion on USG was marked with a gadolinium-based contrast agent under USG guidance. After a single non-enhanced T1 weighted control MR sequence, positively correlated lesions with initial MRI were sampled by USG guided core biopsy. Of the 37 lesions evaluated, 32 (86%) lesions showed a correlation between MRI and SLUS findings. On SLUS core biopsy, there were eight (25%) malignant and 11 (34.4%) high-risk lesions among these 32 cases with correlated MRI findings; while the remaining 13 (40.6%) cases had benign histopathology. Eleven (34.4%) of the SLUS-discovered lesions were focus, 11 (34.4%) were non-mass enhancements, and the remaining 10 (31.2%) were mass lesions. Of the five lesions (13.5%) that showed no correlations on MRI and SLUS examinations, four were non-mass enhancements and one was focus. SLUS represents a method for identifying MRI-detected lesions and provides a bridge to ultrasound-guided biopsy for histopathological diagnosis. There is a need for confirmation of biopsies to avoid false negative results. We describe a cheap, safe, and easy-to-apply USG-guided pre-biopsy lesions marking method in order to ensure definite correlation.

Radiomics models based on non-enhanced MRI can differentiate chondrosarcoma from enchondroma

To develop and validate radiomics models based on non-enhanced magnetic resonance (MR) imaging for differentiating chondrosarcoma from enchondroma. We retrospectively evaluated a total of 68 patients (including 27 with chondrosarcoma and 41 with enchondroma), who were randomly divided into training group (n=46) and validation group (n=22). Radiomics features were extracted from T1WI and T2WI-FS sequences of the whole tumor by two radiologists independently and selected by Low Variance, Univariate feature selection, and least absolute shrinkage and selection operator (LASSO). Radiomics models were constructed by multivariate logistic regression analysis based on the features from T1WI and T2WI-FS sequences. The receiver-operating characteristics (ROC) curve and intraclass correlation coefficient (ICC) analyses of the radiomics models and conventional MR imaging were performed to determine their diagnostic accuracy. The ICC value for interreader agreement of the radiomics features ranged from 0.779 to 0.923, which indicated good agreement. Ten and 11 features were selected from the T1WI and T2WI-FS sequences to construct radiomics models, respectively. The areas under the curve (AUCs) of T1WI and T2WI-FS models were 0.990 and 0.925 in training group and 0.915 and 0.855 in the validation group, respectively, showing no significant differences between the two sequence-based models (P&gt;0.05). In all the cases, the AUCs of the two radiomics models based on T1WI and T2WI-FS sequences and conventional MR imaging were 0.955, 0.901 and 0.569, respectively, demonstrating a significantly higher diagnostic accuracy of the two sequence-based radiomics models than conventional MR imaging (P&lt;0.01). The radiomics models based on T1WI and T2WI-FS non-enhanced MR imaging can be used for the differentiation of chondrosarcoma from enchondroma.

Assessment of Articular Cartilage Disorders After Distal Radius Fracture Using Biochemical and Morphological Nonenhanced Magnetic Resonance Imaging

To assess radiocarpal articular cartilage after distal radius fracture, with and without intra-articular extension, compared with healthy controls using multiparametric, nonenhanced magnetic resonance imaging (MRI). In this prospective study, multiparametric MRI of the radiocarpal articular cartilage was performed in 26 participants (16 males and 10 females; mean age, 39.5 ± 14.7 years; range, 20-70 years) using 3T MRI. The cohort consisted of 14 patients with a distal radius fracture and 12 healthy volunteers. The radiocarpal articular cartilage was assessed using morphological (Double Echo Steady-State [DESS] and True Fast Imaging With Steady-State Precession [TrueFISP]) and biochemical (T2∗) MRI sequences without an intravenous contrast agent. The modified Outerbridge classification system for morphological analyses and region-of-interest biochemical analysis were applied to assess the degree of articular cartilage damage in each patient. Morphological articular cartilage assessment showed no difference between the DESS sequence and the reference standard, TrueFISP. In the morphological (DESS and TrueFISP) and biochemical (T2∗) assessments, patients with intra-articular fractures did not show articular cartilage damage different from those with extra-articular fractures. Greater articular cartilage degradation was observed after distal radius fracture compared with controls. Posttraumatic radiocarpal articular cartilage damage did not differ between fractures with intra-articular and extra-articular extension, but patients with fractures had notably higher articular cartilage degradation compared with healthy controls. Magnetic resonance imaging using advanced multiparametric sequences may facilitate accurate, noninvasive assessment of articular cartilage changes after distal radius fracture without the need for a contrast agent. Diagnostic IV.

Perfusion-based functional magnetic resonance imaging for differentiating serous borderline ovarian tumors from early serous ovarian cancers in a rat model.

Differentiation of borderline tumors from early ovarian cancer has recently received increasing attention, since borderline tumors often affect young women of childbearing age who desire to preserve fertility. However, previous studies have demonstrated that non-enhanced magnetic resonance imaging (MRI) sequences cannot sufficiently differentiate these tumors. To investigate the value of dynamic contrast-enhanced MRI (DCE-MRI) and intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in differentiating serous borderline ovarian tumors (SBOT) from early serous ovarian cancers (eSOCA). Twenty SBOT and 20 eSOCA rat models were performed with DCE-MRI and IVIM-DWI at 3.0-T MR scanner. Qualitative and quantitative parameters of DCE-MRI were acquired and compared between two groups and correlated with the microvessel density (MVD). The receiver operating characteristic (ROC) curve analyses were conducted to determine their differentiating performances. SBOTs presented significantly lower values of the initial area under the enhancement curve (iAUC), volume transfer constant (Ktrans), and extracellular extravascular volume fraction (ve) (P < 0.05) and a significantly higher value of true diffusion (D) (P = 0.001) compared with eSOCAs. The diagnostic effectiveness of ve combined with D was significantly better than that of ve or Ktrans alone (P ≤ 0.039). DCE-MRI may represent a promising tool for differentiating SBOTs from eSOCAs and may not be replaced by IVIM-DWI. Combining DCE-MRI with DWI may improve the diagnostic performance of ovarian tumors.

Acute Kidney Injury After Radiocontrast-Enhanced Computerized Tomography in Hospitalized Patients With Advanced Renal Failure: A Propensity-Score-Matching Analysis.

The overall risk of postcontrast acute kidney injury (PC-AKI) after computerized tomography (CT) is negligible, likely because of the small volume of injected iodinated contrast media required. However, the safety of contrast media-enhanced CT in patients with advanced renal functional impairment, an established major risk factor for PC-AKI, is unknown. This is a retrospective study using large data analysis of hospitalized patients at a single center. Adults undergoing CT or magnetic resonance imaging were included in the study and were stratified by estimated glomerular filtration rate (eGFR) (≤30 or >30 mL/min/1.73 m) and by either contrast-enhanced or nonenhanced imaging. Only patients with serial determination of creatinine before and after imaging were included. Demographic, clinical, and laboratory data between groups were analyzed and compared using univariate analysis, propensity score matching, and multivariate logistic regression analysis. A total of 22,319 imaging studies were included. Patients with an eGFR of 30 mL/min/1.73 m or lower undergoing contrast-enhanced CT (n = 403) had an increased risk to develop PC-AKI than did similar patients undergoing enhanced or nonenhanced magnetic resonance imaging (n = 96) or nonenhanced CT (n = 1576) or patients undergoing contrast-enhanced CT with a preprocedural eGFR higher than 30 mL/min/1.73 m (n = 9173). These findings remained robust after propensity matching for demographic, procedural, and clinical parameters. Multivariate regression analysis of all patients undergoing CT with preimaging eGFR of 30 mL/min or lower (n = 1979) revealed that iodine-based contrast enhancement increased the likelihood of post-CT AKI by 51% (confidence interval, 1.23-2.05). Although radiocontrast-enhanced CT is considered safe in most hospitalized patients and in ambulatory settings, the risk of PC-AKI remains significant among inpatients with substantial preimaging renal functional impairment. Caution is warranted using iodine-based enhanced CT in hospitalized patients with an eGFR of 30 mL/min/1.73 m or lower.