Apparent Diffusion Coefficient Cutoff Research Articles

Added Advantages of DWI MR Imaging and ADC Mapping in the Diagnosis of Active Sacroiliitis of Axial Seronegative SpA

Aim: To evaluate the effectiveness of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping in diagnosing active sacroiliitis in patients with axial seronegative spondyloarthropathy (SpA). Material and Methods: This prospective study comprised 26 patients with MR imaging detected active sacroiliitis categorised as a case group, and compared them with healthy controls. ADC value measurements were obtained from the sacral and iliac sides of the bilateral S.I. joints in each case and control group. Independent samples t-test, Chi-square test, and ROC curve analysis were used. Result: Twenty-six patients had active sacroiliitis in 45 S.I. joints, unilateral active sacroiliitis was observed in seven patients (26.9%), bilateral symmetrical in three patients (11.5%) and bilateral asymmetrical in 16 patients (61.5%). The mean ADC value was 1.447 ± 0.528 [SD] × 10–3 mm 2 /s in the right S.I. joint and 1.630 ± 0.441 [SD] × 10–3 mm 2 /s in the left S.I. joint in active sacroiliitis (case group). The mean ADC value of the right S.I. joint was 0.965 ± 0.123 [SD] × 10–3 mm 2 /s and the left S.I. joint was 0.967 ± 0.96 [SD] × 10–3 mm 2 /s in inactive sacroiliitis (control group). A significant difference was observed statistically between the active sacroiliitis and the inactive sacroiliitis with a P < .0005. A cut-off mean ADC value of 1.034 ×10–3 mm 2 /s was obtained for differentiating active sacroiliitis from inactive sacroiliitis with a sensitivity of 84.6% and specificity of 84.6% from the ROC curve analysis. Conclusion: Diffusion-weighted MRI imaging with ADC value mapping acts as a sensitive diagnostic technique in the detection of active sacroiliitis in axial seronegative spondyloarthropathies and also helps in assessing the treatment response.

The potential role of breast MRI in evaluation of triple-negative breast cancer and fibroadenoma of less than 3 cm.

The majority of small-sized (<3 cm) triple-negative breast cancer (TNBC) exhibit smooth margins upon palpation and are often oval or rounded masses. Distinguishing these masses preoperatively from fibroadenomas (FAs) would be very meaningful for clinical practice. The aim of our study was to evaluate the magnetic resonance imaging (MRI) appearance of TNBC and differentiate it from FAs. In this retrospective single-center study, we included 37 patients with TNBCs and 36 patients with FAs who underwent breast MRI. We employed the χ2 test and t-test to compare the differences in morphological features, dynamic contrast-enhanced MRI (DCE-MRI) parameters, and apparent diffusion coefficient (ADC) values between the two groups. Additionally, we constructed non-parametric receiver operating characteristic (ROC) curves using ADC values, with pathological results serving as the gold standard. A total of 37 TNBC lesions and 39 FA lesions were included in the final analysis. TNBCs exhibited more frequent irregular shape, irregular margins, peritumoral edema, fast enhancement in the initial phase, rim enhancement, and time-signal intensity curve (TIC) type III compared to FAs (all P<0.05). Conversely, low-signal segregation in T2-weighted imaging (T2WI) and TIC type I were commonly found in FAs. The mean ADC value of TNBCs was significantly lower than that of FAs [(1.104±0.13)×10-3 vs. (1.613±0.16)×10-3 mm2/s, P<0.05]. The cutoff ADC for differentiating TNBCs from FAs was 1.239×10-3 mm2/s, yielding an area under the curve (AUC) of 0.997, a sensitivity of 94.6%, and a specificity of 100%. The morphological presentation of MRI, internal enhancement features of the mass, TIC curves, and ADC values provide valuable differential diagnostic information for TNBC and FA masses with a maximum diameter of less than 3 cm.

The Role of Diffusion-Weighted Imaging in Characterizing Benign and Malignant Breast Lesions: A Retrospective Study.

Introduction Diffusion-weighted imaging (DWI) is a promising magnetic resonance imaging (MRI) technique for differentiating between benign and malignant breast lesions. This study set out to assess the diagnostic utility of DWI and apparent diffusion coefficient (ADC) values in the characterization of breast lesions. Materials and methods A retrospective analysis comprised 30 patients with breast lesions who had breast MRI with DWI. The histopathological findings, ADC readings, and conventional MRI features were all analyzed. The receiver operating characteristic (ROC) curve analysis method was utilized to assess the diagnostic accuracy of DWI. Results Out of the 30 lesions, 22 (73.3%) were benign and eight (26.7%) were malignant. Malignant lesions exhibited significantly lower ADC values (p < 0.001) compared to benign lesions. An ADC cutoff value of 1.1 × 10-3mm2/s was optimal for differentiating benign from malignant lesions, yielding 90.81% sensitivity, 91.51% specificity, and 91.5% accuracy. Conclusion Combining DWI with quantitative ADC analysis is a helpful, non-invasive method for the characterization of breast lesions. It shows excellent diagnostic accuracy in identifying benign and malignant lesions, which may cut down on pointless biopsies and help with patient management.

Apparent Diffusion Coefficient on Diffusion-Weighted Magnetic Resonance Imaging to Predict the Prognosis of Patients with Endometrial Cancer: A Meta-Analysis.

Apparent diffusion coefficient (ADC) derived from diffusion-weighted magnetic resonance imaging (DWI) may help diagnose endometrial cancer (EC). However, the association between ADC and the recurrence and survival of EC remains unknown. We performed a systematic review and meta-analysis to investigate whether pretreatment ADC on DWI could predict the prognosis of women with EC. PubMed, Embase, and Cochrane's Library were searched for relevant cohort studies comparing the clinical outcomes between women with EC having low versus high ADC on pretreatment DWI. Two authors independently conducted data collection, literature searching, and statistical analysis. Using a heterogeneity-incorporating random-effects model, we analyzed the results. In the meta-analysis, 1358 women with EC were included from eight cohort studies and followed for a median duration of 40 months. Pooled results showed that a low pretreatment ADC on DWI was associated with poor disease-free survival (DFS, hazard ratio [HR]: 3.29, 95% CI: 2.04 to 5.31, p < 0.001; I2 = 41%). Subgroup analysis according to study design, tumor stage, MRI Tesla strength, ADC cutoff, follow-up duration, and study quality score showed consistent results (p for subgroup analysis all > 0.05). The predictive value of low ADC for poor DFS in women with EC decreased in multivariate studies compared to univariate studies (HR: 2.59 versus 32.57, p = 0.002). Further studies showed that a low ADC was also associated with poor overall survival (HR: 3.36, 95% CI: 1.33 to 8.50, p = 0.01, I2 = 0). In conclusion, a low ADC on pretreatment DWI examination may predict disease recurrence and survival in women with EC.

The diagnostic efficacy of diffusion tensor imaging in children with chronic kidney disease: correlation with histopathology and serum biomarkers

BackgroundChildren with chronic kidney disease (CKD) usually present with disease impact on growth besides cardiovascular problems that not only impact the patient's health during childhood but also affect their adult life. We aimed to identify the diagnostic role of diffusion tensor imaging (DTI) in CKD in pediatric using its metrics: apparent diffusion coefficient (ADC) and fraction anisotropy (FA).ResultsThis prospective study was performed on thirty-five CKD patients (16 girls, 19 boys; mean age 12.3 ± 2.6 years) and 19 sex- and age-matched controls. Both groups underwent renal DTI and renal function tests. Based on renal biopsy, patients with CKD were further categorized into sclerotic CKD (n = 25) and non-sclerotic CKD (n = 10). Mean FA renal medulla/cortex in CKD (0.18 ± 0.18 and 0.20 ± 0.17) was lower significantly (p = 0.001) than volunteers' (0.31 ± 0.19, 0.27 ± 0.18). The cutoff FA of renal medulla/cortex used for CKD diagnosis was 0.22 and 0.23 with AUC of 0.828, 0.838 and accuracy of 80.8%, 82.8%. Mean of renal medulla/cortex ADC in CKD (2.13 ± 0.23 and 1.93 ± 0.22 × 10−3 mm2/s) was higher significantly (p = 0.001) than that of volunteers' (1.67 ± 0.15 and 1.64 ± 0.133 × 10−3 mm2/s. ADC cutoff value of renal medulla/cortex used for CKD diagnosis was 1.86 and 1.74 × 10−3 mm2/s with AUC of 0.827, 0.82, 0.827, and 0.911, and accuracy of 80.6%, 79.6%, 82.8%, and 84.2%. Renal medulla/cortex FA in sclerotic CKD was significantly different (p = 0.001) from non-sclerotic CKD (0.25 ± 0.07 and 0.26 ± 0.08). Cortical and medullary FA in CKD patients correlated with e-GFR (r = 0.363, r = 0.317) and serum creatinine (r = − 0.467, r = − 0.383).ConclusionsRenal cortical/medullary FA can assist in diagnosing pediatric CKD, predict sclerotic CKD, and correlate with some serum biomarkers.

Refining the predictive value of preoperative apparent diffusion coefficient (ADC) by whole-tumor analysis for facial nerve outcomes in vestibular schwannomas.

Apparent diffusion coefficient (ADC) in MRI has been shown to correlate with postoperative House-Brackmann (HB) scores in patients with vestibular schwannoma despite limited methodology. To rectify limitations of single region of interest (ROI) sampling, we hypothesize that whole-tumor ADC histogram analysis will refine the predictive value of this preoperative biomarker related to postoperative facial nerve function. Of 155 patients who underwent resection of vestibular schwannoma (2014-2020), 125 patients were included with requisite clinical and radiographic data. After volumetric analysis and whole-tumor ADC histogram, regression tree analysis identified ADC cutoff for significant differences in HB grade. Outcomes were extent of resection, facial nerve function, hospital length of stay (LOS), and complications. Regression tree analysis defined three quantitative ADC groups (× 10-6 mm2/s) as high (> 2248.77; HB 1.7), mid (1468.44-2248.77; HB 3.1), and low (< 1468.44; HB 2.3) range (p 0.04). The mid-range ADC group had significantly worse postoperative HB scores and longer hospital LOS. Large tumor volume was independently predictive of lower rates of gross total resection (p <0.0001), higher postoperative HB score (p 0.002), higher rate of complications (p 0.04), and longer LOS (p 0.003). Whole-tumor histogram yielded a robust regression tree analysis that defined three ADC groups with significantly different facial nerve outcomes. This likely reflects tumor heterogeneity better than solid-tumor ROI sampling. Whole-tumor ADC warrants further study as a useful radiographic biomarker in patients with vestibular schwannoma who are considering surgical resection.

Factors associated with decreasing diffusion-weighted imaging-positive area volume after mechanical thrombectomy in patients with large early ischemic changes.

This study aimed to evaluate the factors associated with decreasing diffusion-weighted imaging (DWI) positive areas in patients with large early ischemic changes after mechanical thrombectomy (MT). This retrospective single-center clinical study was conducted between January 2013 and December 2022. We included consecutive patients who underwent MT for acute large-vessel occlusion of the anterior circulation with low pretreatment DWI-Alberta Stroke Program Early Computed Tomography Scores (ASPECTS) (0-5), effective recanalization [thrombolysis in cerebral infarction (TICI) 2b or TICI3], and magnetic resonance imaging (MRI) acquired before and after MT. We measured the DWI-positive area volume before and after MT. The primary endpoint was the after/before-MT DWI-positive area-volume ratio. In total, 28 patients were included in this study. Eight patients (29%) had an after/before-MT DWI-positive area-volume ratio of <1. The median mean apparent diffusion coefficient (ADC) levels of the DWI-positive areas in the groups with a ratio of <1 or >1 were 717 × 10⁶ mm2/s and 637 × 106 mm2/s, respectively (p = 0.011). Multivariate logistic regression analysis showed that ADC level (OR, 1.020 [95% confidence intervals (CIs), 1.001-1.040]; p = 0.040) was an independent predictor of a decreased DWI-positive area after MT. There was a negative correlation between the mean ADC level and the after/before-MT DWI-positive area-volume ratio (p < 0.001, |ρ| = 0.650), and the mean pretreatment ADC cutoff level was 649 × 106 mm2/s (area under the curve (AUC) = 0.806) for predicting a volume ratio of <1. The mean ADC level before-MT correlated with the after/before-MT DWI-positive area-volume ratio. A mean pretreatment ADC cutoff level of 649 × 106 mm2/s predicted a decreased DWI-positive area after MT.

Evaluation of Three Imaging Methods to Quantify Key Events in Pelvic Bone Metastasis.

The purpose of this study is to compare turbo spin echo diffusion-weighted images in radial trajectory (BLADE DWI) with multi-shot echoplanar imaging (RESOLVE DWI) for imaging the metastatic lesion in the pelvic bone to find a correlation between ADC values and standardized uptake values (SUVs) of FDG uptake in PET/CT. The study also seeks to compare the values of metastatic lesions with those of benign bone lesions, specifically red marrow hyperplasia. The retrospective IRB-approved study included patients with bone metastasis and red marrow hyperplasia in the pelvic bone who underwent 3.0 T MRI with BLADE/RESOLVE DWI sequences and F-18 FDG PET/CT within one month. BVC (best value comparator) was used in determining the nature of bone lesions. Apparent diffusion coefficient (ADC) and standardized uptake value (SUV) were measured by a radiologist and a nuclear medicine physician. MRI image quality was graded with a Likert scale regarding the visualization of the sacroiliac joint, sacral neural foramen, hamstring tendon at ischial tuberosity, and tumor border. Signal-to-noise ratio (SNR) and imaging time were compared between the two DWIs. Mean, peak, and maximum SUVs between metastatic and benign red marrow lesions were compared. SUVs and ADC values were compared. AUROC analyses and cut-off values were obtained for each parameter. Mann-Whitney U, Spearman's rho, and Kolmogorov-Smirnov tests were applied using SPSS. The final study group included 58 bone lesions (19 patients (male: female = 6:13, age 52.5 ± 9.6, forty-four (75.9%) bone metastasis, fourteen (24.1%) benign red marrow hyperplasia). ADCs from BLADE and RESOLVE were significantly higher in bone metastasis than red marrow hyperplasia. BLADE showed higher ADC values, higher anatomical scores, and higher SNR than RESOLVE DWI (p < 0.05). Imaging times were longer for BLADE than RESOLVE (6 min 3 s vs. 3 min 47 s, p < 0.05). There was a poor correlation between ADC values and SUVs (correlation coefficient from 0.04 to 0.31). The AUROC values of BLADE and RESOLVE MRI ranged from 0.892~0.995. Those of PET ranged from 0.877~0.895. The cut-off ADC values between the bone metastasis and red marrow hyperplasia were 355.0, 686.5, 531.0 for BLADE min, max, and average, respectively, and 112.5, 737.0, 273.0 for RESOLVE min, max, and average, respectively. The cut-off SUV values were 1.84, 5.01, and 3.81 for mean, peak, and max values, respectively (p < 0.05). Compared with RESOLVE DWI, BLADE DWI showed improved image quality of pelvic bone MRI in the aspect of anatomical depiction and SNR, higher ADC values, albeit longer imaging time. BLADE and RESOLVE could differentiate bone metastasis and red marrow hyperplasia with quantifiable cut-off values. Further study is necessary to evaluate the discrepancy between the quantifiers between PET and MRI.

The value of dynamic contrast-enhanced MRI and diffusion-weighted sequence in the evaluation of endometrial lesions

Background/Aim: Endometrial abnormalities represent a diagnostic challenge due to overlapping imaging features with normal endometrium. Aim of this study was to assess accuracy of dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging (MRI) in evaluation of endometrial lesions in comparison with T2 and to assess local staging validity and degree of myometrial invasion in malignancy. Methods: Forty patients with abnormal vaginal bleeding or sonographic thickened endometrial were recruited. MRI examination of pelvis was per-formed using 1.5 T scanner with a pelvic array coil. Conventional T1-and T2, dynamic contrast-enhanced (DCE) sequences and diffusion-weighted image (DWI) were performed. Results: Mean age of patients was 53.2 years and 60 % of patients COM-plained of post-menopausal bleeding. Irregular margin, type III enhancement curve, a high signal in T2WI and DWI and low signal of apparent diffusion coefficient (ADC) were significantly associated with malignancy. The optimum ADC threshold value for distinguishing benign from malignant endometrial lesions was 0.905 × 10 -3 mm 2 /S, with 95.5 % sensitivity and 92.9 % specificity. DWI was most sensitive to malignant endometrial lesions, followed by DCE (89.6 %, 98.4 %) and T2 (86.7 %, 91.4 %). DWI and DCE staging correlated with FIGO staging (p = 0.0001 and p = 0.019, respectively). DWI had the best sensitivity for myometrial invasion (95.6 %), followed by DCE (91.9 %) and T2WI (90.1 %). All three sequences had 89.7 % specificity. Conclusion: DWI and DCE MRI were superior to conventional MRI at distinguishing malignant from benign endometrial lesions and can improve myometrial invasion depth evaluation and therapy planning when COM-bined with morphological T2WI. ADC cutoff at a high b value improved MRI diagnostic sensitivity and specificity.

Efficacy of apparent diffusion coefficient values for normal submandibular glands and acute submandibular sialadenitis

AbstractObjectiveThis study aimed to assess the apparent diffusion coefficient (ADC) values of normal salivary glands and acute submandibular sialadenitis (SS).MethodsThis retrospective study included 22 patients who underwent magnetic resonance imaging (MRI) at the Nihon University School of Dentistry between February 2018 and May 2022. ADC values were compared between the acute SS and control group. Data with non‐normality confirmed by Shapiro–Wilk test was analyzed using the Mann–Whitney U test, Spearman's correlation coefficient, and a receiver operating characteristic (ROC) curve. Statistical significance was set at p &lt; 0.05.ResultsThe mean ADC values were 1.03 ± 0. 09 × 10−3 and 1.22 ± 0.17 × 10−3 mm2/s in the normal and acute SS groups, respectively (p &lt; 0.001). ROC analysis revealed a cutoff ADC value of 1.1 for distinguishing acute SS from the normal.ConclusionThese findings suggest that ADC values are useful for the quantitative assessment of acute SS.

Diffusion-Weighted Imaging and Chemical Shift Imaging to Differentiate Benign and Malignant Vertebral Lesion: A Hospital-Based Cross-Sectional Study.

Objective The aim of this study was to evaluate the role of diffusion-weighted imaging (DWI) and chemical shift imaging (CSI) for the differentiation of benign and malignant vertebral lesions. Methods Patients with vertebral lesions underwent routine magnetic resonance imaging (MRI) along with DWI and CSI. Qualitative analysis of the morphological features was done by routine MRI. Quantitative analysis of apparent diffusion coefficient (ADC) from DWI and fat fraction (FF) from CSI was done and compared between benign and malignant vertebral lesions. Results Seventy-two patients were included. No significant difference was noted in signal intensities of benign and malignant lesions on conventional MRI sequences. Posterior element involvement, paravertebral soft-tissue lesion, and posterior vertebral bulge were common in malignant lesion, whereas epidural/paravertebral collection, absence of posterior vertebral bulge, and multiple compression fractures were common in benign vertebral lesion ( p < 0.001). The mean ADC value was 1.25 ± 0.27 mm 2 /s for benign lesions and 0.9 ± 0.19 mm 2 /s for malignant vertebral lesions ( p ≤ 0.001). The mean value of FF was 12.7 ± 7.49 for the benign group and 4.04 ± 2.6 for the malignant group ( p < 0.001). A receiver operating characteristic (ROC) curve analysis showed that an ADC cutoff of 1.05 × 10 -3 mm 2 /s and an FF cutoff of 6.9 can differentiate benign from malignant vertebral lesions, with the former having 86% sensitivity and 82.8% specificity and the latter having 93% sensitivity and 96.6% specificity. Conclusion The addition of DWI and CSI to routine MRI protocol in patients with vertebral lesions promises to be very helpful in differentiating benign from malignant vertebral lesions when difficulty in qualitative interpretation of conventional MR images arises.

The usefulness of the apparent diffusion coefficient value in diagnosing acute spinal cord ischemia.

The purpose of our study was to assess the usefulness of the apparent diffusion coefficient (ADC) value in differentiating between a normal spinal cord and a spinal cord with acute ischemia. Control group of 113 and 8 acute spinal cord ischemia patients were enrolled in this study. The ADC values were measured when diffusion-weighted imaging was first performed after the onset of acute spinal cord ischemia. The mean ADC value each of the control group and acute spinal cord ischemia patients was 0.99 ± 0.19 × 10-3 mm2/s and 0.70 ± 0.15 × 10-3 mm2/s. The mean ADC value in patients with acute spinal cord ischemia was significantly lower than that in patients with a normal spinal cord (P < 0.01). We found the cutoff ADC value (0.86 × 10-3 mm2/s) to be a useful indicator of acute spinal cord ischemia (sensitivity = 100.0%, specificity = 71.7%, AUC = 0.92). In conclusions, it is suggested that the ADC value may be useful in the diagnosis of acute spinal cord ischemia.

Value of CT and MR Imaging in Assessment of Loco-regional Ablated Hepatocellular Carcinoma using LI-RADS Treatment Response Algorithm (version 2018)

Aim: The aim of this work is to evaluate the role of multiphasic CT and dynamic contrast enhanced MRI using LI-RADS treatment response algorithm (version 2018) and the added values of diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps in the assessment of loco-Regional ablated Hepatocellular Carcinoma (HCC). Methods: This study included 45 patients with 50 loco-Regional ablated HCC lesions. All patients underwent multiphasic CT scan, diffusion weighted and dynamic contrast enhanced MRI. The reference standards for assessment were based on serum alpha-fetoprotein level and dynamic contrast enhanced MRI. Results: Multi-phasic CT had moderate sensitivity (87.5%) and high specificity (100%) for assessment of HCC LI-RADS treatment response algorithm. Dynamic contrast enhanced MRI had high sensitivity (100%) and specificity (100%) for the assessment of HCC LI-RADS treatment response algorithm. The sensitivity and specificity of DWI to diagnose HCC malignant residual or recurrence were 93.7% and 100%, respectively, with very good performance. The mean ADC values of the malignant residual or recurrence were significantly lower than that of benign post-ablation tissue changes areas and the best ADC cutoff value for differentiation between viable and nonviable lesions was 1.1x10-3 mm²/s. Conclusion: Performance of dynamic contrast enhanced MRI is better than that of multiphasic CT in the assessment of LIRADS treatment response algorithm. DWI and ADC maps could be used as ancillary methods for differentiation between viable and non-viable loco-regional ablated HCC lesions and should be included in LR-TR treatment response algorithm.

Magnetic resonance imaging for prospective assessment of local recurrence of non-small cell lung cancer after stereotactic body radiation therapy

ObjectivesTo evaluate multi-parametric MRI for distinguishing stereotactic body radiation therapy (SBRT) induced pulmonary fibrosis from local recurrence (LR). Materials and methodsSBRT treated non-small cell lung cancer (NSCLC) patients suspected of LR by conventional imaging underwent MRI: T2 weighted, diffusion weighted imaging, dynamic contrast enhancement (DCE) with a 5-minute delayed sequence. MRI was reported as high or low suspicion of LR. Follow-up imaging ≥12 months or biopsy defined LR status as proven LR, no-LR or not-verified. ResultsMRI was performed between 10/2017 and 12/2021, at a median interval of 22.5 (interquartile range 10.5–32.75) months after SBRT. Of the 20 lesions in 18 patients: 4 had proven LR, 10 did not have LR and 6 were not verified for LR due to subsequent additional local and/or systemic therapy. MRI correctly identified as high suspicion LR in all proven LR lesions and low suspicion LR in all confirmed no-LR lesions. All proven LR lesions (4/4) showed heterogeneous enhancement and heterogeneous T2 signal, as compared to the proven no-LR lesions in which 7/10 had homogeneous enhancement and homogeneous T2 signal. DCE kinetic curves could not predict LR status. Although lower apparent diffusion coefficient (ADC) values were seen in proven LR lesions, no absolute cut-off ADC value could determine LR status. ConclusionIn this pilot study of NSCLC patients after SBRT, multi-parametric chest MRI was able to correctly determine LR status, with no single parameter being diagnostic by itself. Further studies are warranted.

Differentiating sinonasal malignant melanoma from squamous cell carcinoma using DWI combined with conventional MRI.

This study aimed to investigate the feasibility of diffusion-weighted imaging (DWI) in combination with conventional MRI features to differentiate sinonasal malignant melanoma (SNMM) from sinonasal squamous cell carcinoma (SNSCC). A total of 37 patients with SNMM and 44 patients with SNSCC were retrospectively reviewed. Conventional MRI features and apparent diffusion coefficients (ADCs) were evaluated independently by two experienced head and neck radiologists. ADCs were obtained from two different regions of interest (ROIs) including maximum slice (MS) and small solid sample (SSS). Multivariate logistic regression analysis was performed to identify significant MR imaging features in discriminating between SNMM and SNSCC. Receiver operating characteristic (ROC) curves were used to assess the diagnostic performance. SNMMs were more frequently located in the nasal cavity, with well-defined border, T1 Septate Pattern (T1-SP) and heterogeneous T1 hyperintensity, whereas SNSCCs were more frequently located in the paranasal sinus, with homogenous T1 isointensity, ill-defined border, reticular or linear T2 hyperintensity, and pterygopalatine fossa or orbital involvement (all p < 0.05). The mean ADCs of SNMM (MS ADC, 0.85 × 10-3mm2/s; SSS ADC, 0.69 × 10-3mm2/s) were significantly lower than those of SNSCC (MS ADC, 1.05 × 10-3mm2/s; SSS ADC, 0.82 × 10-3mm2/s) (p < 0.05). With a combination of location, T1 signal intensity, reticular or linear T2 hyperintensity, and a cut-off MS ADC of 0.87 × 10-3mm2/s, the sensitivity, specificity, and AUC were 97.3%, 68.2%, and 0.89, respectively. DWI combined with conventional MRI can effectively improve the diagnostic performance in differentiating SNMM from SNSCC.

Characterizing Various Posterior Fossa Tumors in Children and Adults With Diffusion-Weighted Imaging and Spectroscopy.

Background Theposterior fossa is situated between thetentorium cerebelli above and the foramen magnum below. Vital structures like the cerebellum, the pons, and the medulla are situated within it; hence, tumors within the posterior fossa are considered one of the most critical brain lesions. Children are more likely to develop posterior fossa tumors than adults. Diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) sequences along with the conventional MRI helpin providing additional information in the characterization of the various posterior fossa tumors. We hereby present a series of 30 patients with clinically suspected posterior fossa masses who underwent preoperative MRI. Objectives This study aims to differentiate the neoplastic from non-neoplastic posterior fossa mass by evaluating the diffusion restriction pattern on DWI, quantifying the apparent diffusion coefficient (ADC) map in various posterior fossa tumors, and comparing the different metabolites of various posterior fossa tumors on MRS. Results Out of the 30 patients with posterior fossa lesions, 18 were males and 12 were females. Eight of them were in the pediatric age group, while twenty-two of them were adults. Metastasis was the most common posterior fossa lesionin our study sample and was found in six patients (20%), followed by vestibular schwannomas (17%) and arachnoid cysts (13%), meningiomas, medulloblastoma, and pilocytic astrocytoma (10% each) and epidermoid, ependymoma, and hemangioblastoma (7% each). The mean ADC value of benign tumors was higher than that of malignant tumors, and this difference was found to be significant (p = 0.012). The cut-off ADC value 1.21x 10-3mm2/s had a sensitivity of 81.82% and specificity of 80.47%. MRS metabolites played an additional role in differentiating benign from malignant tumors. Conclusion A combination of conventional MRI, DWI,ADC values, and MRS metabolites showed good diagnostic accuracy to differentiate between the various posterior fossa neoplastic tumors both in adults and children.

High predictive ability of apparent diffusion coefficient value for wall-invasion pattern of advanced gallbladder carcinoma.

The wall-invasion pattern classification of advanced gallbladder carcinoma (GBC) has been reported. However, its association with clinical findings remains unclear. We aimed to clarify relationships between clinicopathological characteristics, prognosis, and apparent diffusion coefficient (ADC) values of advanced GBC based on the wall-invasion pattern. We reviewed the data of 37 patients who had undergone advanced GBC cholecystectomy at our institution between 2009 and 2021. Clinicopathological findings, prognosis, and ADC values were retrospectively analyzed. Based on the wall-invasion pattern, patients were classified into infiltrative growth (IG) type (n = 22) and destructive growth (DG) type (n = 15). In the DG-type, the incidence of venous invasion (P = 0.027), neural invasion (P = 0.008), and lymph node metastasis (P = 0.047) was significantly higher than in the IG-type, and recurrent-free survival (RFS) was significantly shorter (P = 0.015); the median RFS was 11.4months (95% confidence interval, 6.3-16.5months) in the DG-type and not reached in the IG-type. The ADC value in the DG-type was significantly lower than in the IG-type (median, 1.19 × 10-3 mm2/s vs. 1.86 × 10-3 mm2/s, P < 0.001). The area under the receiver operating characteristic curve for the ADC values to differentiate wall-invasion patterns was 0.95 (95% confidence interval, 0.87-1.00). The optimal cutoff ADC value was 1.45 × 10-3 mm2/s (sensitivity, 92.9%; specificity, 90.9%). The wall-invasion pattern of advanced GBC is associated with its aggressiveness and prognosis, and can be predicted by ADC values with high accuracy.

Diagnostic Efficacy of Diffusion-weighted Imaging in Distinguishing Chronic Diffuse Sclerosing Osteomyelitis from Suppurative Osteomyelitis of the Mandible.

Chronic diffuse sclerosing osteomyelitis (CDSO) is a non-suppurative inflammatory bone disease diagnosed based on combined clinical, histopathological, and radiological findings. Accurate diagnosis is important since CDSO is more refractory to treatment than suppurative osteomyelitis. The purpose of this study was to determine the diagnostic efficacy of diffusion-weighted imaging (DWI) in the quantitative assessment of CDSO to distinguish it from acute suppurative osteomyelitis (ASO) and chronic suppurative osteomyelitis (CSO) of the mandible. Using a retrospective cohort study design, we analyzed MRI data of 6 patients with CDSO and 34 patients with ASO and CSO. The mean apparent diffusion coefficient (ADC) values of the three groups (CDSO, ASO, and CSO groups) were calculated, and differences were analyzed using Kruskal-Wallis and post-hoc Mann-Whitney tests with Bonferroni adjustments. We performed a receiver operating characteristic (ROC) curve analysis to evaluate the ability of the ADC to predict CDSO. P < 0.05 was considered statistically significant. The mean ADCs in the CDSO, ASO, and CSO groups were 1.22 ± 0.04 × 10-3 mm2/s, 1.28 ± 0.08 × 10-3 mm2/s, and 1.06 ± 0.09 × 10-3 mm2/s, respectively. Significant differences were observed between the ASO and CSO groups (P < 0.001) and CSO and CDSO groups (P < 0.01). However, there was no significant difference between the ASO and CDSO groups (P = 0.21). The ROC analysis revealed a cut-off ADC value of 1.19 for distinguishing the CSO group from the CDSO group. Sensitivity, specificity, accuracy, and area under the ROC curve were 1.0, 0.92, 0, 95, and 0.94, respectively. The results suggest that ADC may be useful in distinguishing CDSO from mandibular suppurative osteomyelitis.

Diagnostic value of WB-DWI versus 18F-FDG PET/CT for the detection of multiple myeloma.

Whole-body diffusion-weighted imaging (WB-DWI) is commonly used for the detection of multiple myeloma (MM). Comparative data on the efficiency of WB-DWI compared with F-18 fluoro-2-deoxy-d-glucose positron emission tomography-computed tomography (18F-FDG PET/CT) to detect MM is limited. This was a retrospective, single-center study of 22 patients with MM enrolled from January 2018 to December 2019. All patients underwent WB-DWI and 18F-FDG PET/CT. Pathological and clinical manifestations, as well as radiologic follow-up, were used for diagnosis. The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of both methods were compared. The apparent diffusion coefficient (ADC) values of MM lesions and false-positive lesions were estimated. A total of 214 MM bone lesions were evaluated. There was no significant difference in the accuracy of WB-DWI and PET/CT (86.92 versus 88.32%). Though WB-DWI had a higher sensitivity (99.26% versus84.56%) and PET-CT had a higher specificity (96.10% versus 64.56%), these differences were not statistically significant. There was a statistically significant difference in PPV (83.33% versus 96.64%) and NPV (98.08% versus 77.89%) of WB-DWI and PET/CT, respectively. The ADC value for MM lesions was significantly lower than that for false-positive lesions (P < 0.001). Receiver operating curve analysis showed that the AUC was 0.846, and when the cut-off value was 0.745 × 10-3 mm2/s, the sensitivity and specificity were 86.3 and 83.4%, respectively, which distinguished MM lesions from non-MM lesions. WB-DWI and PET-CT scans have similar overall accuracy for detecting MM lesions. The higher PPV of PET-CT and NPV of WB-DWI make them complementary imaging modalities. The ADC value for MM lesions is significantly lower than that for false-positive lesions. An ADC cutoff value of 0.745 × 10-3 mm2/s results in sensitivity and specificity of 86.3 and 83.4%, respectively.

Comparison of Apparent Diffusion Coefficient Value Measurement and Contrast-Enhanced T1-Weighted Imaging in Detecting Active Demyelinating Lesions in Multiple Sclerosis

Objective: To find a difference in apparent diffusion coefficient (ADC) values of non-enhancing and enhancing lesions in patients with multiple sclerosis (MS) and to find a cutoff ADC value to predict the enhancement of the MS lesion. Materials and Methods: A retrospective review of magnetic resonance imaging (MRI) of the brain in MS patients between January 2015 and December 2019 was done. The MS plaques in the images were mapped in fluid attenuation inversion recovery (FLAIR) and post-contrast T1- weighted imaging sequences (T1WI). The lesions were categorized into enhancing and non-enhancing lesions based on the presence of enhancement on post-contrast T1WI. The ADC value of each lesion was measured using circular regions of interest (ROI) placed in the enhancing portion. The difference in mean ADC values between the two groups was assessed. Results: There were 22 patients with 194 MS lesions. The mean ADC values of the enhancing lesions at 0.891±0.164×10⁻³ mm²/s were significantly lower than those of the non-enhancing lesions at 1.303±0.280×10⁻³ mm²/s (p&lt;0.001). A cutoff ADC value of 1.117×10⁻³ mm²/s was used to distinguish between the enhancing and the non-enhancing lesions. The best results were obtained with a sensitivity of 93.9%, specificity of 71.4%, positive predictive value (PPV) of 40.3%, negative predictive value (NPV) of 98.3%, and accuracy of 75.3%. Conclusion: ADC value measurement can be used to predict the enhancement of the MS plaque, which may be helpful as a screening tool for active demyelinating plaque in MS patients. Keywords: Multiple sclerosis; Active demyelinating lesion; Active MS; Contrast-enhanced T1-weighted imaging; ADC value