Application of diffusion-weighted imaging combined with apparent diffusion coefficient in differential diagnosis between central neurocytoma and ependymoma

PURPOSE

Differential diagnosis between central neurocytoma and ependymoma is very important for making preoperative scheme. We explored the application of diffusion-weighted imaging (DWI) combined with apparent diffusion coefficient (ADC) in differential diagnosis between both.

METHODS

The data of preoperative MR plain and contrast-enhanced scan, DWI and ADC values of neoplastic solid parts from 18 cases with central neurocytoma and 19 cases with lateral ventricular ependymoma, were retrospectively analyzed. Mann-Whitney test was used for the comparison of ADC values between central neurocytoma and ependymoma. The application of ADC values in the differential diagnosis between central neurocytoma and ependymoma was evaluated by ROC curve.

RESULTS

The lesions showed hyperintensity-dominant mixed signal intensity on DWI and mean ADC was (0.65 ± 0.13) × 10^-3 mm²/s in the 18 cases with central neurocytoma. In the 19 cases with ependymoma, 13 had hyperintensity-dominant mixed signal intensity on DWI and 6 had hypointensity-dominant mixed signal intensity on DWI, and mean ADC was (1.20 ± 0.23) × 10^-3 mm²/s. The mean ADC value was significantly higher in the 19 cases with ependymoma than in the 18 cases with central neurocytoma (P < 0.001). The ADC of 0.87 × 10^-3 mm²/s might be used as a threshold for differential diagnosis between central neurocytoma and ependymoma with an area under ROC curve of 0.98 ± 0.02 and a 95% confidence interval of 0.95-1.00. Its sensitivity, specificity, and accuracy were 90%, 100%, and 90%, respectively.

CONCLUSION

There is a certain overlap in MRI imaging features between central neurocytoma and ependymoma. DWI combined with ADC value can improve peoperative diagnostic accuracy.

Whole brain apparent diffusion coefficient measurements correlate with survival in glioblastoma patients

INTRODUCTION

Glioblastoma (GBM) is the most common malignant primary brain tumor, and methods to improve the early detection of disease progression and evaluate treatment response are highly desirable. We therefore explored changes in whole-brain apparent diffusion coefficient (ADC) values with respect to survival (progression-free [PFS], overall [OS]) in a cohort of GBM patients followed at regular intervals until disease progression.

METHODS

A total of 43 subjects met inclusion criteria and were analyzed retrospectively. Histogram data were extracted from standardized whole-brain ADC maps including skewness, kurtosis, entropy, median, mode, 15th percentile (p15) and 85th percentile (p85) values, and linear regression slopes (metrics versus time) were fitted. Regression slope directionality (positive/negative) was subjected to univariate Cox regression. The final model was determined by aLASSO on metrics above threshold.

RESULTS

Skewness, kurtosis, median, p15 and p85 were all below threshold for both PFS and OS and were analyzed further. Median regression slope directionality best modeled PFS (p = 0.001; HR 3.3; 95% CI 1.6-6.7), while p85 was selected for OS (p = 0.002; HR 0.29; 95% CI 0.13-0.64).

CONCLUSIONS

Our data show tantalizing potential in the use of whole-brain ADC measurements in the follow up of GBM patients, specifically serial median ADC values which correlated with PFS, and serial p85 values which correlated with OS. Whole-brain ADC measurements are fast and easy to perform, and free of ROI-placement bias.

Does the Apparent Diffusion Coefficient Value Predict Permanent Cerebral Ischemia/Reperfusion Injury in Rats?

RATIONALE AND OBJECTIVES

Variation in tissue damage after cerebral ischemia/reperfusion (I/R) can cause uncertainty in stroke-related studies, which can be reduced if the damage can be predicted early after ischemia by measuring the apparent diffusion coefficient (ADC). We investigated whether ADC measurement in the acute phase can predict permanent cerebral I/R injury.

MATERIALS AND METHODS

The middle cerebral artery occlusion model was established using the intraluminal suture method to induce 60 minutes of ischemia followed by reperfusion in rats. T2-weighted images and diffusion-weighted images were obtained at 30 minutes and 24 hours after ischemia. Neuronal cell survival was assessed by neuronal nuclei (NeuN) immunofluorescence staining. The correlation between relative ADC (rADC) values at 30 minutes and I/R injury at 24 hours after ischemia was analyzed. Magnetic resonance imaging results were confirmed by histologic analysis.

RESULTS

The correlation between rADC values at 30 minutes and 24 hours was strong in the ischemic core and peri-infarct region but moderate in the anterior choroidal and hypothalamic region. Histologic analysis revealed that the correlation between rADC values at 30 minutes and the number of NeuN-positive cells at 24 hours was strong in the ischemic core and peri-infarct region but moderate in the anterior choroidal and hypothalamic region. Furthermore, there was a strong positive correlation between the sum of rADC values of three regions at 30 minutes and the infarct volume at 24 hours.

CONCLUSION

ADC measurement in the acute phase can predict permanent cerebral I/R injury and provide important information for the evaluation of ischemic stroke.

Comparison of free breathing and respiratory triggered diffusion-weighted imaging sequences for liver imaging

BACKGROUND

Diffusion-weighted imaging (DWI) has become a useful tool in the detection, characterization, and evaluation of response to treatment of many cancers, including malignant liver lesions. DWI offers higher image contrast between lesions and normal liver tissue than other sequences. DWI images acquired at two or more b-values can be used to derive an apparent diffusion coefficient (ADC). DWI in the body has several technical challenges. This include ghosting artifacts, mis-registration and susceptibility artifacts. New DWI sequences have been developed to overcome some of these challenges. Our goal is to evaluate 3 new DWI sequences for liver imaging.

AIM

To qualitatively and quantitatively compare 3 DWI sequences for liver imaging: free-breathing (FB), simultaneous multislice (SMS), and prospective acquisition correction (PACE).

METHODS

Magnetic resonance imaging (MRI) was performed in 20 patients in this prospective study. The MR study included 3 separate DWI sequences: FB-DWI, SMS-DWI, and PACE-DWI. The image quality, mean ADC, standard deviations (SD) of ADC, and ADC histogram were compared. Wilcoxon signed-rank tests were used to compare qualitative image quality. A linear mixed model was used to compare the mean ADC and the SDs of the ADC values. All tests were 2-sided and P values of < 0.05 were considered statistically significant.

RESULTS

There were 56 lesions (50 malignant) evaluated in this study. The mean qualitative image quality score of PACE-DWI was 4.48. This was significantly better than that of SMS-DWI (4.22) and FB-DWI (3.15) (P < 0.05). Quantitatively, the mean ADC values from the 3 different sequences did not significantly differ for each liver lesion. FB-DWI had a markedly higher variation in the SD of the ADC values than did SMS-DWI and PACE-DWI. We found statistically significant differences in the SDs of the ADC values for FB-DWI vs PACE-DWI (P < 0.0001) and for FB-DWI vs SMS-DWI (P = 0.03). The SD of the ADC values was not statistically significant for PACE-DWI and SMS-DWI (P = 0.18). The quality of the PACE-DWI ADC histograms were considered better than the SMS-DWI and FB-DWI.

CONCLUSION

Compared to FB-DWI, both PACE-DWI and SMS-DWI provide better image quality and decreased quantitative variability in the measurement of ADC values of liver lesions.

Pathologic Correlation of Cellular Imaging Using Apparent Diffusion Coefficient Quantification in Patients with Brain Metastases After Gamma Knife Radiosurgery

OBJECTIVE

To evaluate the role of apparent diffusion coefficient (ADC) in differentiating radiation necrosis (RN) from recurrent tumor after Gamma Knife radiosurgery (GKRS) for brain metastases (BMs).

METHODS

Forty-one patients with BM who underwent surgical intervention after GKRS at Cleveland Clinic (2006-2017) were included in this retrospective study. The ADC values of the growing lesions and the contralateral hemisphere were calculated using picture archiving and communication system. These values were correlated to the percentage of RN identified on pathologic evaluation of the surgical specimen.

RESULTS

The median age of the patients was 59 years (range, 25-86 years), and lung cancer (63.4%) was the most common malignancy. Median initial (pre-GKRS) target volume of the lesions was 5.4 cc (range, 0.135-45.6 cc), and median GKRS dose was 18.0 Gy. Surgical resection or biopsy was performed at a median of 176 days after GKRS. Two variables were statistically significant predictors of predominate RN (75%-100%) in the surgical specimen: 1) ADC of the lesion on the preresection magnetic resonance imaging (MRI) and 2) initial pre-GKRS target volume. ADC >1.5 × 10^-3 mm²/s within the lesion on MRI predicted significant RN on pathologic evaluation of the lesion (P < 0.05). Similarly, when the target volume before GKRS was large (>10 cc), the risk of identifying significant necrosis in the pathologic specimen was elevated (P < 0.05).

CONCLUSIONS

Our data suggest that the combination of lesion ADC on MRI prior to surgical intervention and the initial target volume can predict RN with reasonable accuracy.

Characteristics of cerebral perfusion and diffusion associated with crossed cerebellar diaschisis after acute ischemic stroke

PURPOSE

We aimed to investigate the possible factors associated with the occurrence of crossed cerebellar diaschisis (CCD) at the hyperacute stage of ischemic stroke using whole-brain volume perfusion CT (VPCT) combined with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We retrospectively analyzed 108 patients with ischemic stroke within 6 h of onset. The VPCT findings of the patients showed a unilateral perfusion deficit in the supratentorial territory. Follow-up MRI examinations were performed within 24 h after onset. The effects of the supratentorial cerebral ischemia, the location distribution, the final infarct volume and the apparent diffusion coefficient (ADC) value on the occurrence and severity of CCD were analyzed.

RESULTS

Among 108 patients with hyperacute cerebral ischemia, 62 (57.4%) demonstrated a contralateral cerebellar perfusion deficit on the VPCT maps. The occurrence of CCD was related to a reduction in cerebral blood volume (CBV) and prolongation of the mean transit time (MTT). Notably, the decrease in the ADC value in the infarct based on follow-up MRI was closely related to the occurrence and severity of CCD.

CONCLUSION

The occurrence and severity of CCD are related to the degree of low supratentorial perfusion and the decrease in the ADC value of infarct focus.

Differentiation of pilocytic and pilomyxoid astrocytomas using dynamic susceptibility contrast perfusion and diffusion weighted imaging

PURPOSE

Pilocytic (PA) and pilomyxoid astrocytomas (PMA) are related low-grade tumors which occur predominantly in children. PMAs have a predilection for a supratentorial location in younger children with worse outcomes. However, the two have similar imaging characteristics. Quantitative MR sequences such as dynamic susceptibility contrast (DSC) perfusion and diffusion (DWI) were assessed for significant differences between the two tumor types and locations.

METHODS

A retrospective search for MRI with DSC and DWI on pathology-proven cases of PMA and PA in children was performed. Tumors were manually segmented on anatomic images registered to rCBV, K2, and ADC maps. Tumors were categorized as PA or PMA, with subclassification of supratentorial and infratentorial locations. Mean values were obtained for tumor groups and locations compared with Student's t test for significant differences with post hoc correction for multiple comparisons. ROC analysis for significant t test values was performed. Histogram evaluation was also performed.

RESULTS

A total of 49 patients met inclusion criteria. This included 30 patients with infratentorial PA, 8 with supratentorial PA, 6 with supratentorial PMA, and 5 with infratentorial PMA. Mean analysis showed significantly increased rCBV for infratentorial PMA (2.39 ± 1.1) vs PA (1.39 ± 0.16, p = 0.0006). ROC analysis for infratentorial PA vs PMA yielded AUC = 0.87 (p < 0.001). Histogram analysis also demonstrated a higher ADC peak location for PMA (1.8 ± 0.2) vs PA (1.56 ± 0.28).

CONCLUSION

PMA has a significantly higher rCBV than PA in the infratentorial space. DSC perfusion and diffusion MR imaging may be helpful to distinguish between the two tumor types in this location.

The diagnostic precision of apparent diffusion coefficient (ADC) in grading of malignant endometrial lesions compared with histopathological findings

OBJECTIVE

The present study aimed to extract apparent diffusion coefficient (ADC) values from the diffusion-weighted imaging (DWI) sequence of endometrial lesions and compare them with tissue specimen results in order to determine the precision of ADC values in grading of malignant endometrial lesions.

METHODS

The present prospective study was conducted on 22 patients complaining of abnormal vaginal bleeding or evidence for endometrial thickening or masses detected using the ultrasound. Sampling was performed for pathological examination. MRI T2W+DWI+T1W+Post Contrast T1W were performed for patients. The statistical analysis was performed in SPSS 20 and MedCalc.

RESULTS

In this study, although the mean ADC value was lower in patients with endometrial cancer than those with benign endometrial lesions, the difference was not significant (0.86 ± 0.2 mm²/sec versus 1.33 ± 0.53 mm²/sec; P = 0.13). Using the cutoff point of 0.53, the sensitivity and specificity of ADC value for differentiating benign and malignant lesions, respectively, equaled 90.91 and 9.09, with an equal positive and negative predictive value of 50%. In patients with endometrioid adenocarcinoma, mean ADC value was 0.93 ± 0.15 in FIGO Grade I, and 0.76 ± 0.165 in FIGO Grade II. Based on the statistical test, no significant difference existed between the two groups in terms of ADC values.

CONCLUSION

Results indicate that the use of a DWI sequence (ADC values) can prevent invasive measures in the diagnosis of benign endometrial lesions and the identification of malignant lesions with a high precision in many patients having accompanying diseases or other cases for which invasive measures cannot be used. Also, there is no significant difference in the mean ADC values between G1 and G2 of endometrioid carcinoma.

Apparent diffusion coefficient-based histogram analysis differentiates histological subtypes of periampullary adenocarcinoma

BACKGROUND

For periampullary adenocarcinoma, the histological subtype is a better prognostic predictor than the site of tumor origin. Intestinal-type periampullary adenocarcinoma (IPAC) is reported to have a better prognosis than the pan-creatobiliary-type periampullary adenocarcinoma (PPAC). However, the classification of histological subtypes is difficult to determine before surgery. Apparent diffusion coefficient (ADC) histogram analysis is a noninvasive, non-enhanced method with high reproducibility that could help differentiate the two subtypes.

AIM

To investigate whether volumetric ADC histogram analysis is helpful for distinguishing IPAC from PPAC.

METHODS

Between January 2015 and October 2018, 476 consecutive patients who were suspected of having a periampullary tumor and underwent magnetic resonance imaging (MRI) were reviewed in this retrospective study. Only patients who underwent MRI at 3.0 T with different diffusion-weighted images (b-values = 800 and 1000 s/mm²) and who were confirmed with a periampullary adenocarcinoma were further analyzed. Then, the mean, 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles of ADC values and ADC_min, ADC_max, kurtosis, skewness, and entropy were obtained from the volumetric histogram analysis. Comparisons were made by an independent Student's t-test or Mann-Whitney U test. Multiple-class receiver operating characteristic curve analysis was performed to determine and compare the diagnostic value of each significant parameter.

RESULTS

In total, 40 patients with histopathologically confirmed IPAC (n = 17) or PPAC (n = 23) were enrolled. The mean, 5th, 25th, 50th, 75th, 90th, and 95th percentiles and ADC_max derived from ADC₁₀₀₀ were significantly lower in the PPAC group than in the IPAC group (P < 0.05). However, values derived from ADC₈₀₀ showed no significant difference between the two groups. The 75th percentile of ADC₁₀₀₀ values achieved the highest area under the curve (AUC) for differentiating IPAC from PPAC (AUC = 0.781; sensitivity, 91%; specificity, 59%; cut-off value, 1.50 × 10^-3 mm²/s).

CONCLUSION

Volumetric ADC histogram analysis at a b-value of 1000 s/mm² might be helpful for differentiating the histological subtypes of periampullary adenocarcinoma before surgery.

[Value and related factors of preoperative diagnosis of extramural vascular invasion of rectal cancer by 3.0T magnetic resonance imaging]

Objective: To evaluate the value of preoperative diagnosis of extramural vascular invasion (EMVI) of rectal cancer with 3.0T high-resolution magnetic resonance imaging (MRI) and the MRI-related factors of EMVI in rectal cancer. Methods: The clinical and imaging data of 40 patients with rectal cancer were retrospectively analyzed. The postoperative pathological diagnosis was used as the gold standard to evaluate the diagnostic efficacy of preoperative diagnosis of EMVI of rectal cancer by high-resolution MRI, and to analyze the relationship between the EMVI and clinical and MRI features. Results: Of the 40 patients, 19 cases were diagnosed as positive EMVI and 21 were negative by MRI. Pathological diagnosis of EMVI was positive in 10 cases and negative in 30 cases. The sensitivity, specificity and accuracy of MRI in the diagnosis of EMVI were 100%, 70.0% and 77.5%, respectively. Preoperative MRI and postoperative pathology were moderately consistent in the diagnosis of EMVI in rectal cancer (Kappa=0.538, P<0.001). Pathological EMVI positivity were related to tumor size under MRI examination (P=0.028), degree of differentiation (P<0.001), depth of invasion (P=0.002), lymph node metastasis (P=0.001), liver metastasis (P=0.011), tumor apparent diffusion coefficient (ADC) value (P=0.010) and exponential apparent diffusion coefficient (eADC) value (P=0.003). It also related to extramural nerve invasion by pathological examination (P=0.005). Conclusion: According to the EMVI imaging score of rectal cancer, preoperative MRI has a high value in the diagnosis of EMVI of rectal cancer.

Comparison of MR imaging features of uterine neuroendocrine carcinoma and uterine malignant lymphoma

PURPOSE

We retrospectively investigated the characteristic magnetic resonance (MR) imaging findings of uterine neuroendocrine carcinoma (UNEC) compared to those of uterine malignant lymphoma (UML).

METHODS

Nine consecutive female patients with UNEC and 5 female patients with UML participated in this study. MR imaging features were evaluated retrospectively.

RESULTS

On MR imaging, seven of 9 UNEC lesions and no UML lesions showed an exophytic growth pattern. All 9 UNEC lesions and no UML lesions showed a growth pattern along the surface of the endocervix or endometrium. Only 1 UNEC lesion and all 5 UML lesions showed diffuse enlargement of the uterus. No UNEC lesions and all 5 UML lesions showed a multinodular shape. These findings showed significant differences between lesions. Findings for margin, endophytic growth pattern, signal intensity, and homogeneity on T2-weighted and T1-weighted imaging did not differ significantly between lesion types. Apparent diffusion coefficient was significantly lower for UML lesions than for UNEC lesions, but was quite low for both types. Local invasion to surrounding tissues was more frequent in UML lesions than in UNEC lesions. There was no significant difference in the frequency of lymphadenopathy between two entities.

CONCLUSIONS

UNEC lesions tended to show an exophytic growth pattern and growth along the surface of the endocervix or endometrium, even when diffuse enlargement of the uterus was present, while all UML lesions showed a multinodular shape and diffuse enlargement of the uterus without thickening of the cervical epithelium and endometrium.

Image Quality and ADC Assessment in Turbo Spin-Echo and Echo-Planar Diffusion-Weighted MR Imaging of Tumors of the Head and Neck

RATIONALE AND OBJECTIVES

We aimed to compare the distortion ratio (DR), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) between turbo spin-echo (TSE)-diffusion-weighted imaging (DWI) and echo-planar imaging (EPI)-DWI of the orofacial region and prove the usefulness of TSE-DWI for the differential diagnosis of orofacial lesions.

MATERIALS AND METHODS

The DR, SNR, and CNR of both sequences were compared in 42 cases. Then, the apparent diffusion coefficient (ADC) of various orofacial lesions obtained by TSE-DWI was investigated in 143 lesions.

RESULTS

In the first study, 38 of 42 cases were analyzed. TSE-DWI showed a significantly lower DR (p < 0.05) and higher SNR and CNR than EPI-DWI (p < 0.05), indicating the superiority of TSE-DWI. In the second study, 114 cases (79.3%) were successfully analyzed. When lesions were divided into cysts, benign tumors, squamous cell carcinoma, malignant lymphoma, and other malignant tumors (OT), significant differences were observed in all pairs of lesions (p < 0.05) except squamous cell carcinoma and OT (p = 0.877). The area under the curve for distinguishing benign from malignant tumors was 0.80 with a cutoff ADC of 1.29 × 10^-3 mm²/s.

CONCLUSION

TSE-DWI produced better quality images than EPI-DWI. TSE-DWI yields the high possibility of obtaining ADC in the orofacial region, and this value was considered useful for the differential diagnosis of orofacial lesions.

Accuracy, criteria, and clinical significance of visual assessment on diffusion-weighted imaging and apparent diffusion coefficient quantification for diagnosing acute appendicitis

PURPOSE

To assess the accuracy, criteria, and clinical significance of diffusion-weighted imaging (DWI) signal intensity and apparent diffusion coefficient (ADC) quantification for diagnosing acute appendicitis.

METHODS

Fifty-one patients with right lower abdominal pain [uncomplicated appendicitis (n = 25), complicated appendicitis (n = 10), and non-appendicitis (n = 16)] who underwent MR examination were enrolled in this retrospective study. Two radiologists independently measured appendiceal diameter and wall thickness. They assessed whether a wall defect, an abscess, extraluminal air, or an appendicolith was present on axial T2WI; evaluated intensity on DWI using a 5-point scale; and determined the ADC values of the appendix and peri-appendiceal tissue. Statistical analysis was performed to assess imaging findings for the diagnosis of appendicitis and complicated appendicitis. Cut-off values were determined using receiver operating characteristic analysis.

RESULTS

For diagnosing acute appendicitis, the accuracy improved from 78.4% using only T2WI to 86.3% using combined T2WI and DWI for reader 1 and from 82.4 to 86.3% for reader 2. For the appendix, the cut-off ADC values that diagnosed appendicitis were 1.41 × 10^-3 and 1.26 × 10^-3 mm²/s with accuracies of 78.4% and 76.5%, respectively. For the peri-appendiceal tissue, these values of 1.03 × 10^-3 and 0.91 × 10^-3 mm²/s differentiated between uncomplicated and complicated appendicitis with an accuracy of 97.1%.

CONCLUSIONS

Combined DWI and T2WI provided high accuracy for diagnosing appendicitis. The inflamed appendix had lower ADC value than the normal appendix. The peri-appendiceal tissue presenting low ADC value was a notable finding of complicated appendicitis.

Changes in Apparent Diffusion Coefficient as Surrogate Marker for Changes in Ki-67 Index Due to Neoadjuvant Chemotherapy in Patients with Invasive Breast Cancer

RATIONALE AND OBJECTIVES

To evaluate possible correlation between changes in apparent diffusion coefficient (ADC) and Ki-67 index as a result of neoadjuvant chemotherapy (NAC) in patients with invasive breast cancer.

METHODS AND MATERIALS

Between February 2016 and October 2017, 87 patients with breast cancer underwent diffusion-weighted magnetic resonance imaging (b = 0 and 800 sec/mm²) before and after NAC. ADC and tumor diameter before and after NAC were compared to the Ki-67 index determined from biopsy or surgical specimens.

RESULTS

Ki-67 index did not correlate significantly with ADC before NAC (p = 0.862) or afterwards (p = 0.292), nor did it correlate with tumor diameter before (p = 0.545) or afterwards (p = 0.478). However, change in ADC as a result of NAC correlated inversely with change in Ki-67 index (r = -0.326, p = 0.002). The percentage change in Ki-67 index did not correlate with the percentage change in ADC (p = 0.404). Similarly, the change in Ki-67 index or percentage change in that index did not correlate with the change in tumor diameter (p = 0.075) or percentage change in tumor diameter (p = 0.233).

CONCLUSION

Comparison of pre- and post-NAC ADC can be used to estimate the change in Ki-67 index in patients with invasive breast cancer.

Gray matter nuclei damage in acute carbon monoxide intoxication assessed in vivo using diffusion tensor MR imaging

OBJECTIVE

To observe the structural changes of gray matter nuclei in patients with acute carbon monoxide intoxication by diffusion tensor imaging (DTI), quantify the degree of deep gray matter damage in the brain by adopting imaging technology and research the characteristics of the damage and its pertinence with memory and cognitive impairment.

METHODS

Twenty-five patients with acute carbon monoxide intoxication and 25 healthy volunteers matched in sex and age were examined by routine head MRI and diffusion tensor imaging (DTI). Bilateral hippocampus, dater nucleus, thalamus, amygdala, globus pallidus and putamen were taken as regions of interest. The mean diffusion coefficient (MD), anisotropic fraction (FA) and appearance of deep gray matter nucleus in patients with acute carbon monoxide intoxication were analyzed. It found that the change of diffusion coefficient (ADC) and its clinical correlation with cognitive impairment were generated by carbon monoxide intoxication.

RESULTS

Compared with the healthy control group, the FA values of bilateral globus pallidus, hippocampus, dater nucleus and putamen decreased, while the FA values of amygdala and thalamus had no statistical significance; the MD values and ADC values of hippocampus, globus pallidus and putamen increased, while the MD and ADC values of dater nucleus, thalamus and amygdala had no statistical significance, either.

CONCLUSION

DTI is capable of sensitively reflecting the damage of gray matter nuclei caused by acute carbon monoxide intoxication and quantifying the degree of hypoxic brain damage in a certain extent, and may be related to cognitive impairment.

Histogram analysis of apparent diffusion coefficient and fluid-attenuated inversion recovery in discriminating between enhancing and nonenhancing lesions in multiple sclerosis

PURPOSE

This study evaluates the diagnostic performance of apparent diffusion coefficient (ADC) and T2 fluid-attenuation inversion recovery (T2 FLAIR) in discriminating between new white matter (WM) enhancing lesions (ELs) and non-enhancing lesions (NELs) in multiple sclerosis (MS) patients.

METHODS

Thirty MS patients with a new solitary WM lesion on brain MRI were analyzed. A region-of-interest was drawn on all lesions and the contralateral normal-appearing WM (NAWM) on T2 FLAIR and ADC maps. Normalized ratios of T2 FLAIR and ADC were calculated by dividing lesion value by the contralateral NAWM. Histogram analysis was performed on the T2 FLAIR, ADC values, and their normalized ratios. Mann-Whitney U test was used to compare histogram parameters and receiver operating characteristic (ROC) analysis determined the area under the curve (AUC).

RESULTS

T2 FLAIR histogram parameters were not significantly different between ELs and NELs. Several EL ADC histogram parameters, including maximum and mean, were significantly higher than NELs (p = 0.006 to p = 0.031). There was a trend toward significantly higher maximum ADC in ELs after adjusting for multiple comparisons (p = 0.054). The standard deviation of T2 FLAIR (AUC 0.70), maximum ADC (AUC 0.79), and normalized maximum ADC ratio (AUC 0.75) were among histogram parameters with the highest diagnostic performance. A maximum ADC cutoff of 1274 × 10^-6 mm²/s provided a 0.86 sensitivity and 0.75 specificity.

CONCLUSION

In patients with contraindications to gadolinium or concerns with gadolinium brain deposition, consideration may be given to ADC and T2 FLAIR as potential noncontrast methods for the evaluation of active MS lesions.

[Clinical application value of prognosis of nutrition index and apparent diffusion coefficient in patient with hepatocellular carcinoma underwent transarterial chemoembolization]

Objective: To explore clinical application value of prognostic nutrition index(PNI) and apparent diffusion coefficient(ADC) in treating hepatic arterial chemoembolization (TACE) of patients with hepatic cell carcinoma (HCC). Methods: A total of 77 patients with HHC of BCLC B were retrospectively analyzed in Dalian Medical University Affiliated Second Hospital who were diagnosed for the first time and received TACE treatment from October 2017 to December 2018, of whom 64 Males, 13 females, mean age was 54±13 years.At 1 month after surgery, TACE efficacy was evaluated according to revised solid tumor evaluation criteria (mRECIST), the enrolled patients were divided into TACE effective group (41 cases, 53.2%) and TACE ineffective group (36 cases, 46.8%) to compare ability of PNI and ability of ADC alone or in combination in evaluating efficacy of TACE and the relationship between these two groups. Results: Overall postoperative PNI of enrolled patients was decreased compared with preoperative PNI, 47.7±6.6 vs 48.3±5.9 (P<0.05), preoperative and postoperative PNI of TACE effective group were all higher than that of TACE ineffective group (49.9±6.0 vs 46.6±5.3, 50.6±5.4 vs 44.4±5.1,all P<0.05), there was no significant difference in PNI between the treatment groups (P>0.05). The value of ADC in postoperative tumor region increased compared with that in preoperative tumor region ((1.43±0.15) ×10(-3) vs (1.28±0.08) ×10(-3) mm(2)/s, P<0.05), the difference between postoperative tumor region ADC value and postoperative normal liver parenchyma had no statistical significance(P>0.05). Overall postoperative PNI and tumor region ADC value of enrolled patients had linear correlation (P<0.05).Threshold value of PNI and ADC value in preoperative prediction were 51.05 and 1.32×10(-3) mm(2)/s; postoperative evaluation threshold value were 50.11 and 1.41×10(-3) mm(2)/s.Postoperative combination of PNI and ADC had the highest value in evaluating TACE efficacy. Conclusions: TACE postoperative PNI and tumor region ADC are related. PNI and tumor region ADC could be used in predicting and evaluating TACE efficacy in HCC patients, combination of these two could further increase the efficiency.

Quantitative Assessment of Bladder Cancer Reflects Grade and Recurrence: Comparing of Three Methods of Positioning Region of Interest for ADC Measurements at Diffusion-weighted MR Imaging

PURPOSE

To determine the impact of three different regions of interests (ROIs) positioning methods for apparent diffusion coefficient (ADC) measurements on the assessment of the grade and recurrence and to examine the correlation between ADC value and histopathological grade/ Ki-67 labeling index (LI) in patients with bladder cancer.

MATERIALS AND METHODS

Sixty-one patients with bladder cancer were retrospectively evaluated. Two observers measured mean ADC values using whole-volume-ROIs, single-section-ROI and three-ROIs methods. Interclass correlation coefficient was analyzed to assess interobserver variability. The grade and recurrence in patients with bladder cancer were assessed by calculating the areas under the receiver operating characteristic curves with Az values. Spearman's correlation was used to analyze the correlations of ADC value with grade and Ki-67 LI.

RESULTS

For the mean ADC value, the interclass correlation coefficient were excellent with the whole-volume and the single-section method (0.90 [95% CI: 0.84, 0.94] and 0.89 [95% CI: 0.81, 0.93]) and was good with the three-ROIs method (0.72 [95% CI: 0.53, 0.83]). The Az value for determining histological grade and recurrence of bladder cancer were not significantly different from each positioning method (all p > 0.05). There's significant correlation between histological grade and ADC measuring by whole-volume-ROIs and single-section-ROI methods (r = 0.31, p = 0.02; r = 0.37, p < 0.05). The ADC measured by whole-volume-ROIs, single-section-ROI, and three-ROIs methods were significantly and inversely correlated with the Ki-67 LI (r = -0.3; r = -0.49; r = -0.40, all p < 0.05).

CONCLUSION

There's no significant difference among any of the ROI positioning methods in evaluation of tumor grade and recurrence. There's significant correlation between histological grade and ADC measuring by whole-volume-ROIs and single-section-ROI methods. The ADC value obtained by either of three methods was significantly and inversely correlated with the Ki-67 LI.

Cerebral blood volume and apparent diffusion coefficient - Valuable predictors of non-response to bevacizumab treatment in patients with recurrent glioblastoma

BACKGROUND

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The core of standard of care for newly diagnosed GBM was established in 2005 and includes maximum feasible surgical resection followed by radiation and temozolomide, with subsequent temozolomide with or without tumor-treating fields. Unfortunately, nearly all patients experience a recurrence. Bevacizumab (BV) is a commonly used second-line agent for such recurrences, but it has not been shown to impact overall survival, and short-term response is variable.

METHODS

We collected MRI perfusion and diffusion images from 54 subjects with recurrent GBM treated only with radiation and temozolomide. They were subsequently treated with BV. Using machine learning, we created a model to predict short term response (6 months) and overall survival. We set time thresholds to maximize the separation of responders/survivors versus non-responders/short survivors.

RESULTS

We were able to segregate 21 (68%) of 31 subjects into unlikely to respond categories based on Progression Free Survival at 6 months (PFS6) criteria. Twenty-two (69%) of 32 subjects could similarly be identified as unlikely to survive long using the machine learning algorithm.

CONCLUSION

With the use of machine learning techniques to evaluate imaging features derived from pre- and post-treatment multimodal MRI, it is possible to identify an important fraction of patients who are either highly unlikely to respond, or highly likely to respond. This can be helpful is selecting patients that either should or should not be treated with BV.

Diffusion-weighted MRI with ADC mapping for response prediction and assessment of oesophageal cancer: A systematic review

PURPOSE

The aim was to perform a systematic review on the value of diffusion-weighted MRI (DW-MRI) with apparent diffusion coefficient (ADC) mapping in the prediction and assessment of response to chemo- and/or radiotherapy in oesophageal cancer.

MATERIALS AND METHODS

A systematic search was performed on Pubmed, Embase, Medline and Cochrane databases. Studies that evaluated the ADC for response evaluation before, during or after chemo- and/or radiotherapy were included. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the quality of the included studies.

RESULTS

Fourteen studies, comprising 516 patients, in which the response to treatment in oesophageal cancer was evaluated on ADC maps were included. Acquisition parameter settings for DW-MRI and ROI placement varied substantially. The reference standard was RECIST or endoscopic assessment in eight non-surgery studies and histopathology after surgery in six studies. A high pre-treatment ADC significantly correlated with good response in three out of 12 studies; conversely, one study reported a significantly higher pre-treatment ADC in poor responders. In five out of eight studies good responders showed a significantly larger relative increase in ADC two weeks after the onset of treatment (range 23-59%) than poor responders (range 1.5-17%). After chemo- and/or radiotherapy ADC results varied considerably, amongst others due to large variation in the interval between completion of therapy and DW-MRI.

CONCLUSION

DW-MRI for response evaluation to chemo- and/or radiotherapy in oesophageal cancer shows variable methods and results. A large relative ADC increase after two weeks of treatment seems most predictive for good response.

Associations Between Diffusion Dynamics and Functional Outcome in Acute and Early Subacute Ischemic Stroke

PURPOSE

The current study aimed to investigate the associations between diffusion dynamics of ischemic lesions and clinical functional outcome of acute and early subacute stroke.

MATERIAL AND METHODS

A total of 80 patients with first ever infarcts in the territory of the middle cerebral artery underwent multi-b-values diffusion-weighted imaging and diffusion kurtosis imaging. Multiple diffusion parameters were generated in postprocessing using different diffusion models. Long-term functional outcome was evaluated with modified Rankin scale (mRS) at 6 months post-stroke. Good functional outcome was defined as mRS score ≤ 2 and poor functional outcome was defined as mRS score ≥ 3. Univariate analysis was used to compare the diffusion parameters and clinical features between patients with poor and good functional outcome. Significant parameters were further analyzed for correlations with functional outcome using partial correlation.

RESULTS

In univariate analyses, standard-b-values apparent diffusion coefficient (ADC_st) ratio and fractional anisotropy (FA) ratio of acute stroke, ADC_st ratio and mean kurtosis (MK) ratio of early subacute stroke were statistically different between patients with poor outcome and good outcome (P < 0.05). When the potential confounding factor of lesion volume was controlled, only FA ratio of acute stroke, ADC_st ratio and MK ratio of early subacute stroke remained correlated with the functional outcome (P < 0.05).

CONCLUSION

Diffusion dynamics are correlated with the clinical functional outcome of ischemic stroke. This correlation is independent of the effect of lesion volume and is specific to the time period between symptom onset and imaging. More effort is needed to further investigate the predictive value of diffusion-weighted imaging.

Diffusion-weighted imaging of hepatocellular carcinoma before and after transarterial chemoembolization: role in survival prediction and response evaluation

BACKGROUND

Survival outcomes of patients with hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) are heterogeneous. Measuring the apparent diffusion coefficient (ADC) using diffusion-weighted imaging (DWI) may improve overall survival prediction.

AIM

To assess the value of measuring the ADC before and after TACE in predicting overall survival.

METHODS

A retrospective analysis was performed in HCC patients treated with TACE at a tertiary referral center between 2008 and 2017. The ADC values and changes in ADC value (ΔADC) of HCC lesions (≥ 1 cm) and liver parenchyma were assessed by DWI ≤ 3 months before and after first TACE. Pre- and post-TACE ADC values were compared with tumor response according to mRECIST and correlated with overall survival (OS) in a univariable and multivariable Cox-regression analysis.

RESULTS

A total of 89 patients were included, mostly Child-Pugh A (85%) and BCLC stage B (53%) with a median OS of 21.7 months (95% CI 17.6-25.9). Tumor ADC increased from 1081 mm²/s before (IQR 964-1225) to 1328 mm²/s (IQR 1197-1560) after TACE (p < 0.001). Responders according to mRECIST showed a higher ΔADC after first TACE than non-responders (26 vs. 14%, p = 0.048). Pre-TACE ADC and ΔADC were not significantly associated with OS in both univariable and multivariable analysis, whereas response according to mRECIST remained an independent predictor of OS.

CONCLUSION

mRECIST was confirmed as an independent prognostic factor of OS, but pre- or post-TACE ADC measurements were not. Response according to mRECIST was associated with a higher increase in ADC than non-response.

Volumetric histogram analysis of apparent diffusion coefficient for predicting pathological complete response and survival in esophageal cancer patients treated with chemoradiotherapy

BACKGROUND

The purpose of the study was to evaluate whether histogram analysis of apparent diffusion coefficient (ADC) can predict pathological complete response (pCR) and survival in patients with esophageal squamous cell carcinoma (ESCC) after chemoradiotherapy (CRT).

METHODS

We retrospectively identified 58 patients with ESCC who underwent surgery after CRT between 2007 and 2016. Associations of pretreatment histogram derived ADC parameters with pathological response and survival were analyzed.

RESULTS

Tumors achieved pCR (10 patients, 17.2%) showed significant lower ADC, higher kurtosis, and higher skewness than those of non-pCR (p = 0.005, 0.007, <0.001, respectively). Receiver operating characteristics analysis demonstrated skewness was the best predictor for pCR (AUC = 0.86), with a cut off value of 0.50 (accuracy, 86.2%). In Kaplan-Meier analysis, patients with higher skewness tumors (≥0.50) showed a significantly better recurrence free survival (p = 0.032, log-rank).

CONCLUSIONS

Histogram analysis of ADC can enable prediction of pCR and survival in ESCC patients treated with preoperative CRT.

A SHORT SUMMARY

ADC histogram analysis can be an imaging biomarker for esophageal cancer patients treated with CRT.

Value of diffusion MR imaging in differentiation of recurrent head and neck malignancies from post treatment changes

PURPOSE

Role of diffusion-weighted (DW) MR imaging in differentiating residual or recurrent neck malignancies from postoperative/post-radiation changes with histopathological correlation and comparison with PET-CT.

METHODS AND MATERIALS

Prospective observational study for a period of 1 year in 62 post-radiation/post-operative patients suspected to have residual/recurrent tumors of neck with lesion diameter more than 5 mm measured on MRI.

RESULTS

Mean ADC for recurrent/residual tumors: 1.008 ± 0.220 × 10^-3 mm²/s - significantly lower than mean ADC value for post-treatment changes of 1.69 ± 0.40 × 10^-3 mm²/s (p < 0.0001). The overall diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the qualitative assessment for the use of DWI in differentiating tumors recurrence from post-treatment changes were 96.6%, 96% and 83.3%, respectively. Upon quantitative analysis of the DW imaging data, a threshold ADC value of 1.3 × 10^-3 mm²/s used for differentiating between post-treatment changes and recurrent cancers showed the highest combined sensitivity of 94%, specificity of 83.3%, accuracy of 93.6%, positive predictive value of 95.9%, and negative predictive value of 83.3%.

CONCLUSION

DW MRI is a promising non-invasive MRI technique used to differentiate recurrent/residual head and neck malignancies from posttreatment changes based on ADC values. DWI offers advantage as it has a short scanning time and can be safely added to standard MRI protocol with minimum patient discomfort. Complementary use of DWI and PET/CT imaging may increase diagnostic confidence for differentiating recurrent disease from radiation therapy-induced changes after 6-12 months in posttreatment cases.

Diffusion weighted cardiovascular magnetic resonance imaging for discriminating acute from non-acute deep venous Thrombus

BACKGROUND

The importance of discriminating acute from non-acute thrombus is highlighted. The study aims to investigate the feasibility of readout-segmented diffusion weighted (DW) cardiovascular magnetic resonance (CMR) for discrimination of acute from non-acute deep venous thrombus (DVT).

METHODS

For this prospective study from December 2015 to December 2017, 85 participants (mean age = 53 years, age range = 34~74) with DVT of lower extremities underwent readout-segmented DW CMR. DVT of ≤14 days were defined as acute (n = 55) and > 14 days as non-acute (n = 30). DVT visualization on b = 0, b = 800, and apparent diffusion coefficient (ADC) images were assessed using a 4-point scale (0~3, poor~excellent). DW CMR parameters were measured using region of interest (ROI). Relative signal intensity (rSI) and ADC were compared between acute and non-acute DVT using a Mann Whitney test. Sensitivity and specificity for ADC and rSI were calculated.

RESULTS

ADC maps had higher visualization scores than b = 0 and b = 800 images (2.7 ± 0.5, 2.5 ± 0.6, and 2.4 ± 0.6 respectively, P<0.05). The mean ADC was higher in acute DVT than non-acute DVT (0.56 ± 0.17 × 10- 3 vs. 0.22 ± 0.12 × 10- 3 mm2/s, P<0.001). Using 0.32 × 10- 3 mm2/s as the cutoff, sensitivity and specificity for ADC to discriminate acute from non-acute DVT were 93 and 90% respectively. Sensitivity and specificity were 73 and 60% for rSI on b = 0, and 75 and 63% for rSI on b = 800.

CONCLUSIONS

Readout segmented diffusion-weighted CMR derived ADC distinguishes acute from non-acute DVT.

TRIAL REGISTRATION

This study is retrospectively registered.

TRIAL REGISTRATION NUMBER

HUST-TJH-2015-146 .