Higher Apparent Diffusion Coefficient Values Research Articles

Apparent Diffusion Coefficient of Diffusion Weighted Imaging have Strong Correlation with the Malignancy Grading of Intracranial Tumor

Background and purpose: Accurate imaging diagnosis before surgery is fundamental to determine whether a tumor is benign or malignant. Diagnosis only from structural MRI is not specific. However, the diffusivity of the benign and malignant lesion is different and could be measured by ADC. The Apparent Diffusion Coefficient (ADC) values are calculated automatically by application software and displayed as a parametric map that reflects the degree of diffusion of water molecules through different tissues. The purpose of this study was to analyze the correlation between Diffusion-Weighted Magnetic Resonance Imaging (DWI) and Apparent Diffusion Coefficient (ADC) values with histopathology grading of brain tumors. Material and methods: Pathology reports of intracranial tumor material were correlated with diffusivity of the tumor, and the ADC values, performed within 2 years of post-operative histopathology study. A freehand closed ROI out-lined the whole visible tumor on the most representative slice of ADC maps defined as the slice with the maximum diameter of the solid neoplastic component. ADC values were taken from 2 averages of 2 ROIs. Spearman Correlation test was used to assess the correlation between ADC values with the malignancy grading of the tumor. Result: Low-grade malignant tumors show facilitated diffusion with high ADC values, and high-grade malignant tumors show restricted diffusion with low ADC values. The mean ADC value of Grade I tumor is 1.0799 ± 0.2356 x 10−3 mm2/sec and the mean ADC value of Grade IV tumor is 0.6798 ± 0.23729 x 10−3 mm2/sec. The Spearman correlation test between ADC value and histopathology result shown r = -0.536 and p=0.000 and the test result for ADC value and DWI shown r=-0.706 and p=0.000 (Sig. 0.05). Conclusion: There was strong correlation between DWI and ADC values with histopathology grading of intracranial tumors.

Role of magnetic resonance imaging in diagnosis of pediatric posterior fossa tumors

Objective The aim was to study the role of MRI in diagnosis of pediatric posterior fossa tumors. Background Brain tumors represent the most common solid neoplasms in children and the second most common pediatric malignancy following leukemia. Patients and methods A retrospective study was conducted on 25 pediatric patients with known brain posterior fossa masses, who ranged in age from 1 to 15 years and had suspected posterior fossa tumor by computed tomography. All participants attended the MR unit of Radiology Department, Menoufia University, Menoufia Governorate, during the period from October 2016 to November 2017. Complete history taking, clinical examination, and MR data were compared with histopathology obtained from all patients. Results The mean age of the cases was 7.2 ± 3.9 years. The most common tumors were medulloblastoma (MB) and pilocytic astrocytoma. MB showed restricted diffusion with low apparent diffusion coefficient value, and pilocytic astrocytoma showed free diffusion with higher apparent diffusion coefficient value. High-grade tumors such as MB and brain stem glioma showed elevated choline and reduced N-acetyl aspartate in magnetic resonance spectroscopy curve. Low-grade tumors such as low-grade glioma showed mild rise of choline and mild reduction of creatine in magnetic resonance spectroscopy curve. Conclusion Conventional MRI provided limited information regarding tumor type and grade, falling short as a definitive diagnostic examination. Advanced brain MRI techniques provided incremental diagnostic value over conventional MRI. However, no single advanced technique was perfect, but different techniques typically complement one another.

Role of Diffusion-Weighted MRI in Colorectal Cancer

AbstractBackground: To reveal the adding value of diffusion-weighted Magnetic Resonance Imaging (MRI) in the detection and differential diagnosis of the colorectal cancer, comparing the results of Apparent Diffusion Coefficient (ADC) value with histopathological studies.Aim of Study: The aim of the study was to determine the effectiveness of MRI in the diagnosis of colorectal cancers and to reveal the adding value of DWI in the detection and differential diagnosis of the colorectal cancer, comparing the results of ADC value with histopathological studies.Material and Methods: Fifteen patients with suspected colorectal cancers clinically, endoscopically or by CT and US images were included in this study. All cases have been evaluated with 1.5 MR scanner. In addition to the conventional sequences (T2-axial, sagittal and coronal weighted images (WI), axial T2 STIR, T1 WI and a Diffusion-Weighted Images (DWI) with 4 different b-values (0, 400, 600 and 1000s/mm2 and ADC maps were obtained then the results have been compared to histopathological diagnosis.Results: All cases of malignant colorectal cancer showed high signal (restricted diffusion) on DWI. Receiver Operating Curve (ROC) analysis of ADC values yielded an Area Under Curve (AUC) of 0.912, setting a threshold ADC value of Conclusion: DWI with high b-values and ADC value is a feasible method and has the potential to be effective in detection of colorectal cancer.

Computed tomography and magnetic resonance imaging features of solid serous cystadenomas of the pancreas.

Solid serous cystadenomas (SSC) of the pancreas are the rarest benign type of serous cystic neoplasms and are frequently misdiagnosed, resulting in unnecessary invasive surgical procedures. A retrospective study was performed to collect imaging features of SSC using computed tomography (CT) and magnetic resonance imaging. The clinical data and imaging study of 5 female patients with pathologically confirmed SSC (mean age, 44.2 years; range, 23–69 years) diagnosed between January 2006 and July 2017 were retrospectively analyzed. The imaging study was assessed by two experienced radiologists in consensus. All patients had tumors with a mean size of 2.3 cm (range, 1.5–3.2 cm; 4/5 lesions ≤3 cm). The tumors were located in the tail of pancreas in 3 cases and in the neck of the pancreas in 2 cases. The tumors were all well defined, with an ovoid and lobulated shape and fibrous capsules. Consequently, they presented as low density on unenhanced CT images, marked hyperintensity on T2-weighted images in 4 cases and slight hyperintensity in 1 case. However, they exhibited heterogeneous wash-in and wash-out enhancement in 2 cases and moderate and prolonged enhancement in 3 cases. The apparent diffusion coefficient (ADC) values of the lesions were >2×10−3 mm2/sec. Therefore, a small tumor size, signal intensity on T2-weighted images, high ADC values, fibrous capsules and enhancement patterns may be indicative imaging features of SSCs.

Perihematomal Edema After Spontaneous Intracerebral Hemorrhage.

Perihematomal Edema After Spontaneous Intracerebral Hemorrhage.

Magnetic Resonance Imaging of Uncommon Hepatic Mesenchymal Tumours: Haemangioendothelioma and Angiosarcoma.

Primary Hepatic Epithelioid Haemangioendothelioma (HEHE) and Primary Hepatic Angiosarcoma (PHA) are rare mesenchymal tumours with different malignant potential. Whereas HEHE demonstrates low to intermediate malignant potential, PHA is an aggressive malignancy with poor prognosis. The knowledge of typical imaging features of these lesions may facilitate correct diagnosis; however, the ultimate diagnosis of HEHE and PHA is based on histopathologic examination. The most typical findings helpful in diagnosing HEHE are: Presence of multiple, confluent nodules located at the liver periphery (in young to middle-aged woman), retraction of the liver capsule, marked hyperintensity on T2-weighted images, "target-sign" appearance, progressive centripetal contrast enhancement, and relatively high Apparent Diffusion Coefficient (ADC) values. More than ≥50% of nodules are hyper- or isointense on Hepatobiliary Phase (HBP) images. The imaging features suggestive of PHA are: Occurrence of metastases (lungs, spleen) at the time of diagnosis, presence of a large dominant mass with smaller satellites, heterogeneity and areas of haemorrhage in a dominant mass, progressive contrast enhancement, slightly elevated ADC values as compared to other malignant liver tumours.

DWI of Pancreatic Ductal Adenocarcinoma: A Pilot Study to Estimate the Correlation With Metastatic Disease Potential and Overall Survival.

The purpose of this study is to analyze the relationship between the apparent diffusion coefficient (ADC) of pancreatic ductal adenocarcinoma (PDAC) and the presence or development of metastasis and overall survival (OS). Of 290 consecutive patients with histopathologically proven PDAC from January 2013 to December 2014, staging DWI was performed for 124 patients. Image quality was adequate in 112 studies. Sixty-five patients were treatment naïve, but 17 of the 65 were excluded because of the presence of other associated pancreatic pathologic abnormalities. Data for the remaining 48 patients (24 men and 24 women; median age, 65.5 years; interquartile range, 56-77 years) were obtained during a 4-year follow-up period (mean [± SD], 397 ± 415.1 days). The correlation between ADC and the presence or development of metastasis was assessed using descriptive statistics. OS was determined and mortality analysis was performed using Pearson correlation and Kaplan-Meier curves. Of 48 patients, 10 had metastases at staging MRI, and 12 later developed metastatic disease. Among the latter, the mean time from staging MRI to metastasis was 258 ± 274.1 days. Most (86%) metastases were hepatic (n = 19). During the follow-up period, the remaining 26 patients (54%) never developed metastases. Patients with metastatic disease (n = 22) had significantly lower mean ADCs than did those without metastases (1.27 × 10-3 vs 1.43 × 10-3 mm2/s; p = 0.047). The ADC of PDAC had a positive correlation with survival: patients with PDAC with lower ADCs (< 1.36 × 10-3 mm2/s) had significantly worse 4-year OS rates than did patients with higher ADC values (p = 0.036). Pretreatment ADC values of PDAC may be significantly lower in patients who have or will develop metastatic disease and may correlate with worse OS.

Mass-forming intrahepatic cholangiocarcinoma: Can diffusion-weighted imaging predict microvascular invasion?

Microvascular invasion (MVI) is a risk factor influencing the survival rate of patients with mass-forming intrahepatic cholangiocarcinoma (IMCC). To investigate whether diffusion-weighted imaging (DWI) could be useful in predicting MVI of IMCC. Retrospective. Eighty patients with surgically resected single IMCC (21 MVI-positive lesions and 59 MVI-negative lesions). Preoperative hepatic MRI (1.5T), including T1 - and T2 -weighted images (T1 WI, T2 WI), DWI, and dynamic enhancement imaging. Morphologic characteristics including contour of the lesion, biliary dilation and hepatic capsule retraction, signal features on T1 WI, T2 WI, and DWI, and dynamic enhancement patterns were qualitatively evaluated. The quantitative analysis was performed for the size and apparent diffusion coefficient (ADC) values. Chi-square test, Fisher's exact test, and the independent t-test were used for univariate analysis to determine the relationships between these radiological parameters and the presence of MVI. Logistic regression analysis was used to identify the independent predictors of MVI among these radiological parameters. Receiver operating characteristic curve analysis was performed to evaluate their diagnostic performance. Larger tumor size (P = 0.006) and higher ADC values (P < 0.001) were positively correlated with MVI. Multivariate logistic regression analysis demonstrated that the ADC value (odds ratio, 3.099; P = 0.001) was an independent predictor for MVI of IMCC. The ADC value for MVI of IMCC showed an area under the receiver operating characteristic curve of 0.782 (optimal cutoff value was 1.59 × 10-3 mm2 /s). Larger tumor size was associated with MVI and higher ADC values can be a useful predictor of MVI during the preoperative evaluation of IMCC. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:315-324.

CT scan and magnetic resonance diffusion-weighted imaging in the diagnosis and treatment of esophageal cancer.

Value of computed tomography (CT) scan and diffusion-weighted imaging (DWI) in the diagnosis and treatment of esophageal cancer was investigated. Seventy-eight patients with esophageal cancer treated in Jinan Central Hospital (Jinan, China) from January 2013 to June 2014 were selected. All patients underwent CT scan and DWI examination, and their clinical history data were analyzed. DWI was conducted. The short-term curative effect and the 3-year survival rate of patients in the high apparent diffusion coefficient (ADC) value group and the low ADC value group were compared; ADC values in the complete remission (CR) group and the partial remission (PR) group were compared. The difference in value between the length of esophageal lesions and the length of pathological specimens measured by CT scan was significantly different from that detected via DWI examination with b=600, 800 and 1,000 sec/mm2, respectively (P<0.05). The diagnostic rate of esophageal cancer via CT scan was significantly lower than that via DWI examination (P<0.05). After radiotherapy, the clinical control rate in the high ADC value group was significantly higher than that in the low ADC value group, and the 3-year survival rate in the former was significantly higher than that in the latter (P<0.05). In the 2nd week during radiotherapy and at the end of radiotherapy, the ADC values in the CR group were significantly higher than those in the PR group (P<0.05). In the 2nd week during radiotherapy and at the end of radiotherapy, ADC values were used to predict the CR rate of radiotherapy for esophageal cancer, and the areas under the receiver operating characteristic (ROC) curve were 0.776 and 0.935, respectively. Compared with CT scan, DWI has higher diagnostic rate and higher sensitivity. The length of esophageal tumor measured by DWI is close to that of pathological entity, which can guide the delineation of the target area of esophageal cancer.

Time course of diffusion tensor imaging metrics in the chronic spinal cord compression rat model.

Diffusion tensor imaging (DTI) provides information about water molecule diffusion in spinal cord. This study was aimed to investigate DTI changes in the different stages of compressive spinal cord induced by water-absorbing material implantation. The spinal cord compression was administered over the fourth cervical vertebral level in rat. Rat models were divided into five subgroups according to compression stages: sham group, group A: three-day compression rat models; group B: 12-day compression rat models; group C: 20-day compression rat models; group D: 60-day compression rat models. DTI including fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the compressive spinal cord were collected. The relationship between the Basso, Beattie, and Bresnahan (BBB) scores and DTI metrics was further explored. Compared with the sham group, BBB scoring of rat model showed a decreased tendency from group A ( P < 0.05) to group B ( P < 0.05). Then the motor function of rat model hindlimbs was recovered in some degree from group C ( P < 0.05) to group D ( P < 0.05) but had significant motor defects when compared with the normal level ( P < 0.05). The DTI metrics results revealed that chronic spinal cord compression resulted in lower FA value and higher ADC value at the compressive spinal cord level assessed at all four time-points ( P < 0.05). DTI metrics also showed a close correlation with motor function ( P < 0.05). DTI is an optimal pre-clinical imaging tool to reflect locomotor performance and pathological status of compressive spinal cord epicenter in chronic spinal cord compression rat model.

Meta-analysis of intravoxel incoherent motion magnetic resonance imaging in differentiating focal lesions of the liver.

Introduction:Accurate detection and characterization of focal liver lesions, including differentiation between malignant and benign lesions, are particularly important. The objective of this meta-analysis was to evaluate the parameters of intravoxel incoherent motion (IVIM), including apparent diffusion coefficient (ADC), pure molecular diffusion coefficient (D), perfusion-related diffusion coefficient (D∗), and perfusion fraction (f) in differentiating focal liver lesions.Methods:IVIM method employed for focal liver lesion and the quality assessment of diagnostic studies were evaluated. Standardized mean differences and 95% confidence intervals were calculated. The heterogeneity was quantified with the I2 statistic.Results:The difference between groups was analyzed according to the I2 values from 6 different studies using fixed effects or random effects models. Significant differences in ADC (P < .001) and D (P < .001) were observed between benign and malignant lesions. Moreover, significant differences in ADC (P < .001), D (P < .001), and f (P = .01) were found between hemangioma and hepatocellular carcinoma (HCC). In addition, no significant difference was observed between the metastases and HCC.Conclusions:D and ADC values were useful for the differentiation between benignity and malignancy; higher values of ADC, D, and f were observed in hemangioma compared to HCC. Nevertheless, IVIM did not result as the optimal approach for differentiation between the metastases and HCC.

Differentiation of Cerebellar Hemisphere Tumors: Combining Apparent Diffusion Coefficient Histogram Analysis and Structural MRI Features

We aimed to develop a diagnostic algorithm for differentiation of cerebellar hemisphere tumors, combining Apparent Diffusion Coefficient (ADC) histogram analysis and structural imaging features. Pretreatment MRI of patients with pathologically proven cerebellar hemisphere neoplasms were reviewed. Voxel-wise volumetric ADC histograms of tumor solid components were determined. Histogram variables, patients' age, and structural imaging features were applied to develop a differential diagnosis algorithm. Among 142 patients, the most common tumors were metastasis (n = 54), hemangioblastoma (n = 39), pilocytic astrocytoma (n = 18), and medulloblastoma (n = 9). On ADC histogram analysis, medulloblastomas had the lowest, and pilocytic astrocytomas had the highest ADC values. An ADC 15th percentile value < 580 × 10-6 mm2 /s could differentiate medulloblastomas from other cerebellar hemisphere tumors with receiver operating characteristic (ROC) area under the curve (AUC) of .98 (P < .001). Comparing the two most common adult cerebellar hemisphere tumors (metastases and hemangioblastomas), hemangioblastomas had higher ADC values; and an ADC 90th percentile value > 2000 × 10-6 mm2 /s could identify hemangioblastomas with ROC AUC of .82 (P < .001). Along with ADC histogram and patients' age, structural imaging features including enhancement pattern, prominent vascular flow voids, surrounding FLAIR hyperintensity, and solid component T2 signal hyperintensity were independent differentiation variables in the diagnostic algorithm. In pretreatment differentiation of cerebellar tumors, the ADC histogram analysis is particularly helpful for distinction of medulloblastomas from other subtypes, and differentiation of the two most common adult tumors (ie, metastases and hemangioblastomas) from each other. Combination of structural imaging features and ADC histogram analysis can help with pretreatment differentiation of cerebellar tumors.

Imaging prediction of isocitrate dehydrogenase (IDH) mutation in patients with glioma: a systemic review and meta-analysis.

To evaluate the imaging features of isocitrate dehydrogenase (IDH) mutant glioma and to assess the diagnostic performance of magnetic resonance imaging (MRI) for prediction of IDH mutation in patients with glioma. A systematic search of Ovid-MEDLINE and EMBASE up to 10 October 2017 was conducted to find relevant studies. The search terms combined synonyms for 'glioma', 'IDH mutation' and 'MRI'. Studies evaluating the imaging features of IDH mutant glioma and the diagnostic performance of MRI for prediction of IDH mutation in patients with glioma were selected. The pooled summary estimates of sensitivity and specificity and their 95% confidence intervals (CIs) were calculated using a bivariate random-effects model. The results of multiple subgroup analyses are reported. Twenty-eight original articles in a total of 2,146 patients with glioma were included. IDH mutant glioma showed frontal lobe predominance, less contrast enhancement, well-defined border, high apparent diffusion coefficient (ADC) value and low relative cerebral blood volume (rCBV) value. For the meta-analysis that included 18 original articles, the summary sensitivity was 86% (95% CI, 79%-91%) and the summary specificity was 87% (95% CI, 78-92%). In a subgroup analysis, the summary sensitivity of 2-hydroxyglutarate magnetic resonance spectroscopy (MRS) [96% (95% CI, 91-100%)] was higher than the summary sensitivities of other imaging modalities. IDH mutant glioma consistently demonstrated less aggressive imaging features than IDH wild-type glioma. Despite the variety of different MRI techniques used, MRI showed the potential to non-invasively predict IDH mutation in patients with glioma. 2-Hydroxyglutarate MRS shows higher pooled sensitivity than other imaging modalities. • IDH mutant glioma showed frontal lobe predominance, less contrast enhancement, well-defined border, high ADC value, and low rCBV value. • The diagnostic performance of MRI for prediction of IDH mutation in patients with glioma is within a clinically acceptable range, the summary sensitivity was 86% (95% CI, 79-91%) and the summary specificity was 87% (95% CI, 78-92%). • In a subgroup analysis, the summary sensitivity of 2-hydroxyglutarate MRS [96% (95% CI, 91-100%)] was higher than the summary sensitivities of other imaging modalities.

Longitudinally extensive vasogenic edema following spinal cord infarction

AbstractAlthough transient lesion expansion has been reported after spinal cord infarction, longitudinally extensive lesion expanding more than several vertebral segments is extremely rare. We report a 45‐year‐old man having spinal cord infarction with subsequent longitudinally extensive lesion expansion on magnetic resonance imaging (MRI) 10 days after the infarction. The length of T2 hyperintense lesion was four vertebral segments on initial MRI but enlarged to span 12 vertebral segments on subsequent MRI, with Lhermitte's sign, but otherwise without neurological deterioration. The expanded lesion extended beyond the anterior spinal artery region with high apparent diffusion coefficient value in the acute phase but improved within 10 days after starting cervical collar, suggesting that lesion expansion was due to vasogenic edema. This case illustrates that transient longitudinal lesion expansion accompanied by spinal cord infarction can reach lengths of up to 12 vertebral segments. Caution should be exercised while interpreting MRI findings to avoid excessive treatment or secondary damage.

Histogram analysis of apparent diffusion coefficient maps in the prognosis of patients with locally advanced head and neck squamous cell carcinoma: Comparison of different region of interest selection methods

ObjectiveTo investigate the influence of different region of interest (ROI) selection methods on the histogram analysis of apparent diffusion coefficient (ADC) maps and to compare their performance in predicting overall survival (OS) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). MethodsA total of 73 patients with locally advanced HNSCC who underwent pretreatment diffusion-weighted magnetic resonance imaging were included. Based on the largest slice ROI (ROILS) and whole tumor ROI (ROIWT), ADC histogram parameters including mean ADC (ADCmean); median ADC (ADCmedian); 10th, 25th, 75th, and 90th percentiles of ADC values (ADC10, ADC25, ADC75, and ADC90); kurtosis; and skewness were obtained. Intraclass correlation coefficients (ICCs) and Bland–Altman plots were used to evaluate measurement reproducibility. The association of ADC histogram parameters and clinicopathological factors with OS was analyzed using log-rank tests and Cox regression. ResultsThe measurements of ADC histogram parameters based on ROIWT showed better reproducibility than ROILS (ICCs for ROIWT: 0.772–0.961; ICCs for ROILS: 0.511–0.851). The higher ADC values (ADCmean, ADCmedian, ADC10, and ADC25 based on both ROIs; ADC75 based on ROILS) and lower kurtosis based on ROILS were significantly associated with worse OS of patients with locally advanced HNSCC (all P < 0.05). In the multivariate Cox analysis, ADC10 measured with ROIWT (P = 0.019, hazard ratio = 2.63, 95% confidence interval 1.17–5.90) was an independent prognostic factor after adjusting for clinicopathological factors. ConclusionsROI selection methods could influence ADC histogram analysis. ADC10 based on ROIWT had the best independent prognostic value for patients with locally advanced HNSCC.

Diffusion-weighted imaging for staging chronic kidney disease: a meta-analysis.

Objective:To evaluate stages of chronic kidney disease (CKD) by apparent diffusion coefficient (ADC) obtained from diffusion weighted imaging (DWI) using a meta-analysis.Methods:Literature databases were searched from PubMed, Web of Science, Cochrane and Embase to identify relevant articles about DWI in CKD between 1999 and 2017. ADC values were extracted from the healthy group and CKD patients with different stages. Meta-analysis was conducted using STATA v. 12.0. A random-effects model was performed to acquire the effect estimate, which was expressed as a pooled weighted mean difference (WMD) with 95% confidence interval (CI). We performed comparisons of ADC values between the following groups: (1) the ADC values of the normal kidneys v s earlier Stage 1–2 of CKD; (2) Stage 3 v s the Stage 1–2 of CKD; (3) the Stage 4–5 v s the Stage 3.Results:Six studies were included in this meta-analysis. The CKD patients with earlier Stage 1–2 showed lower ADC values than the healthy subjects [WMD = −0.09, 95% CI(−0.12 to −0.06), p < 0.001]. However, no obvious difference in ADC values was found between the Stage 3 and Stage1–2 of CKD [WMD = −0.09, 95% CI (−0.18 to 0.01), p = 0.08]. The CKD Stage3 had higher ADC values than those of Stage4–5 [WMD = −0.21, 95% CI (−0.32 to −0.11), p = 0.01].Conclusion:DWI is an accurate and non-invasive imaging technique for early diagnosis and staging of CKD. Quantitative DWI may potentially play a role in making clinical decisions in the follow-up of CKD.Advances in knowledgeDWI can be a valuable tool for staging of CKD.

Characterization of an Orthotopic Rat Model of Glioblastoma Using Multiparametric Magnetic Resonance Imaging and Bioluminescence Imaging.

Glioblastoma multiforme (GBM) is the most common primary brain tumor, with most patients dying within 15–18 months of diagnosis despite aggressive therapy. Preclinical GBM models are valuable for exploring GBM progression and for evaluating new therapeutics or imaging approaches. The rat C6 glioma model shares similarities with human GBM, and application of noninvasive imaging enables better study of disease progression. Here, multiparametric magnetic resonance imaging (mpMRI) and bioluminescence imaging (BLI) were applied to characterize longitudinal development of orthotopic luciferase-expressing C6 tumors. Across all rats (n = 11), a large variability was seen for BLI signal, a relative measure of C6 cell viability, but in most individuals, BLI signal peaked at day 11 and decreased thereafter. T2 and contrast-enhanced T1 tumor volumes significantly increased over time (P < .05), and volume measures did not correlate with BLI signal. After day 11, tumor regions of noncontrast enhancement appeared in postcontrast T1-weighted magnetic resonance imaging, and had significantly higher apparent diffusion coefficient values compared with contrast-enhanced regions (P < .05). This suggests formation of ill-perfused, necrotic regions beyond day 11, which were apparent at end-point–matched tissue sections. Our study represents the first combined use of BLI and mpMRI to characterize the progression of disease in the orthotopic C6 rat model, and it highlights the variability in tumor growth, the complementary information from BLI and mpMRI, and the value of multimodality imaging to better characterize tumor development. Future application of these imaging tools will be useful for evaluation of treatment response, and should be pertinent for other preclinical models.

The diagnostic efficacy of apparent diffusion coefficient value and Choline/Creatine ratio in differentiation between parotid gland tumors

ObjectiveTo detect the diagnostic performance of apparent diffusion coefficient (ADC) value and Cho/Cr ratio in distinguishing various pathological subtypes of parotid gland tumors. Patients and MethodsThis study included 30 patients (14 males and 16 females; age ranged from 25 to 70 years; mean age 50 ± 12.5 years) with 31 parotid gland masses. Diffusion weighted imaging and MR spectroscopy were performed in all patients. ADC values and Cho/Cr ratios were measured for each parotid mass and compared with pathology. The diagnostic performance of ADC value, Cho/Cr ratio, ADC + Cho/Cr ratio and ADC × Cho/Cr ratio for differentiating pathological subtypes were assessed. ResultsPleomorphic adenomas had highest ADC values and Warthin tumors had highest Cho/Cr ratios. ADC value had the best diagnostic performance in differentiating pleomorphic adenomas from Warthin tumors by using cutoff value 1.12 × 10−3 mm2/sec with sensitivity, specificity, PPV, NPV and accuracy 100% for each. ADC value × Cho/Cr ratio had the best diagnostic performance in differentiating malignant from benign tumors, malignant tumors from pleomorphic adenoma and malignant from Warthin’s tumors by using cutoff value 2.37 at which sensitivity, specificity, PPV, NPV and accuracy all were 100%. Conclusion: ADC value and Cho/Cr ratio are useful in differentiating different pathological subtypes of parotid tumors.

Baseline Apparent Diffusion Coefficient as a Predictor of Response to Liver-Directed Therapies in Hepatocellular Carcinoma.

Predicting outcomes in patients with hepatocellular carcinoma (HCC) who undergo locoregional therapies remains a substantial clinical challenge. The purpose of this study was to investigate pre-procedure diffusion weighted magnetic resonance imaging (DW-MRI) as an imaging biomarker for tumoral response to therapy for patients with HCC undergoing drug eluting embolic (DEE) chemoembolization and radioembolization. A retrospective review of HCC patients who underwent DEE chemoembolization or radioembolization was performed. Of the 58 patients who comprised the study population, 32 underwent DEE chemoembolization and 26 underwent radioembolization. There was no significant difference in median apparent diffusion coefficient (ADC) values across the two treatment groups (1.01 × 10−3 mm2/s, P = 0.25). The immediate objective response (OR) rate was 71% (40/56). Tumors with high ADC values were found to have a higher probability of OR within 90 days (odds ratio 4.4, P = 0.03). Moreover, index lesion specific progression free survival (PFS) was greater for high ADC tumors, independent of conventional predictors of treatment response (hazard ratio 0.44, P = 0.01). Low ADC was associated with poorer PFS (P = 0.02). Pre-procedure ADC < 1.01 × 10−3 mm2/s is an independent predictor of poorer immediate OR and index lesion specific PFS in patients with HCC undergoing DEE chemoembolization or radioembolization.

Incremental Prognostic Value of Apparent Diffusion Coefficient Histogram Analysis in Head and Neck Squamous Cell Carcinoma

We aimed to investigate the incremental prognostic value of apparent diffusion coefficient (ADC) histogram analysis in patients with head and neck squamous cell carcinoma (HNSCC) and integrate it into a multivariate prognostic model. A retrospective review of magnetic resonance imaging findings was conducted in patients with pathologically confirmed HNSCC between June 2012 and December 2015. For each tumor, six histogram parameters were derived: the 10th, 50th, and 90th percentiles of ADC (ADC10, ADC50, and ADC90); mean ADC values (ADCmean); kurtosis; and skewness. The clinical variables included age, sex, smoking status, tumor volume, and tumor node metastasis stage. The association of these histogram and clinical variables with overall survival (OS) was determined. Further validation of the histogram parameters as independent biomarkers was performed using multivariate Cox proportional hazard models combined with clinical variables, which was compared to the clinical model. Models were assessed with C index and receiver operating characteristic curve analyses for the 12- and 36-month OS. Ninety-six patients were eligible for analysis. Median follow-up was 877 days (range, 54-1516 days). A total of 29 patients died during follow-up (30%). Patients with higher ADC values (ADC10 > 0.958 × 10-3 mm2/s, ADC50 > 1.089 × 10-3 mm2/s, ADC90 > 1.152 × 10-3 mm2/s, ADCmean > 1.047 × 10-3 mm2/s) and lower kurtosis (≤0.967) were significant predictors of poor OS (P < .100 for all). After adjusting for sex and tumor node metastasis stage, the ADC90 and kurtosis are both significant predictors of OS with hazard ratios = 1.00 (95% confidence interval: 1.001-1.004) and 0.58 (95% confidence interval: 0.37-0.90), respectively. By adding the ADC parameters into the clinical model, the C index and diagnostic accuracies for the 12- and 36-month OS showed significant improvement. ADC histogram analysis has incremental prognostic value in patients with HNSCC and increases the performance of a multivariable prognostic model in addition to clinical variables.