Mean ADCmean Research Articles

Differentiating glioblastoma from primary central nervous system lymphoma of atypical manifestation using multiparametric magnetic resonance imaging: A comparative study

BackgroundThe aim of this study is to evaluate the diagnostic efficiency of magnetic resonance imaging (MRI) of single parameters, unimodality, and bimodality in distinguishing glioblastoma (GBM) from atypical primary central nervous system lymphoma (PCNSL) based on diffusion-weighted imaging (DWI), dynamic susceptibility contrast (DSC) enhancement, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS) findings. MethodsThe cohort included 108 patients pathologically diagnosed with GBM and 54 patients pathologically diagnosed with PCNSL. Pretreatment morphological MRI, DWI, DSC, DTI and MRS were all performed on each patient. The quantitative parameters of multimodal MRI were measured and compared between the patients in the GBM and atypical PCNSL groups, and those parameters showing a significant difference (p < 0.05) between patients in the GBM and atypical PCNSL groups were used to develop one-parameters, unimodality, and bimodality models. We evaluated the efficiency of different models in distinguishing GBM from atypical PCNSL by performing receiver operating characteristic analysis (ROC). ResultsAtypical PCNSL had lower minimum apparent diffusion coefficient (ADCmin), mean ADC (ADCmean), relative ADC (rADC), mean relative cerebral blood volume (rCBVmean), maximum rCBV (rCBVmax), fractional anisotropy (FA), axial diffusion coefficient (DA) and radial diffusion coefficient (DR) values and higher choline/creatine (Cho/Cr) and lipid/creatine (Lip/Cr) ratios than GBM (all p < 0.05). The rCBVmax, DTI and DSC + DTI data were optimal models of single-parameter, unimodality and bimodality for differentiation of GBM from atypical PCNSL, yielding areas under the curves (AUCs) of 0.905, 0.954, and 0.992, respectively. ConclusionsModels of single-parameter, unimodality and bimodality based on muti multiparameter functional MRI may help to discriminate GBM from atypical PCNSL.

Minimal apparent diffusion coefficient in predicting the Ki-67 proliferation index of pancreatic neuroendocrine tumors.

To investigate the diagnostic performance of the minimal apparent diffusion coefficient (ADCmin) to distinguish between pancreatic neuroendocrine tumors (Pan-NETs) with low and high Ki-67 proliferation index values and to evaluate the relationship between ADCmin and the Ki-67 proliferation index. Pre-operative magnetic resonance imaging data and postoperative Ki-67 proliferation index data of 42 patients with primary neuroendocrine tumor of the pancreas from November 2014 to March 2021 were included in this retrospective study. According to the Ki-67 proliferation index value, Pan-NETs were divided into a high-expression group (Ki-67 ≥ 10%, n = 17) and low-expression group (Ki-67 < 10%, n = 25), and mean ADC (ADCmean) and ADCmin values were compared between groups using receiver operating characteristic (ROC) curves to evaluate the performance of ADCmean and ADCmin in judging the expression level of Ki-67 proliferation index. The relationship between ADCmin and the Ki-67 proliferation index was also evaluated. The ADCmin was significantly higher in the low-expression group (Z = - 3.537, p < 0.01). The area under the ROC curve (AUC) for ADCmin was 0.825, which was higher than that for ADCmean (0.781). Using 1.32 × 10-3 mm2/s as the optimal discriminating threshold, the sensitivity, specificity, accuracy, and positive and negative predictive values of the two groups were 80%, 88.2%, 83.3%, 90%, and 75%, respectively. The ADCmin of Pan-NETs showed a significant negative correlation with the Ki-67 proliferation index (rs = - 0.634, p < 0.001). The ADCmin is a potential imaging biomarker, which may be helpful for non-invasive preoperative prediction of the Ki-67 proliferation index of Pan-NETs and the subsequent planning of appropriatetreatment.

The impact of preoperative MRI-based apparent diffusion coefficients on local recurrence and outcome in patients with cerebral metastases

Background Surgery of single cerebral metastases is standard but frequently fails to achieve local tumour control. Reliable predictors for local tumour progression and overall survival are unknown. MRI-based apparent diffusion coefficients (ADC) correlate with tumour cellularity and invasion. The present study analysed a potential relation between the MRI based apparent diffusion coefficients local recurrence and outcome in patients with brain metastases. Methods A retrospective analysis was performed for patients with cerebral metastases and complete surgical resection evaluated by an early postoperative MRI < 72h. Minimal ADC and mean ADC were assessed in preoperative 1,5T-MRI scans by placing regions of interests in the tumour and the peritumoural tissue. Results Analysis of the relation between ADC values, local progression and outcome was performed in 86 patients with a mean age of 59 years (range 33–83 years). Primary site was NSCLC in 37.2% of all cases. Despite complete resection 33.7% of all patients suffered from local in-brain-progression. There were no significant differences in ADC values in groups based on histology. In the present cohort, the mean ADCmin and the mean ADCmean within the metastasis did not differ significantly between patients with and without a later local in-brain progression (634 × 10−6 vs. 661 × 10−6 mm2/s and 1324 × 10−6 vs. 1361 × 10−6 mm2/s; 1100 × 10−6 vs. 1054 × 10−6 mm2/s; each p > 0.05). Mean ADC values did not correlate significantly with PFS and OAS. Conclusion In the present study analysed ADC values had no significant impact on local in brain progression and survival parameters.

Evaluation of various apparent diffusion coefficient measurement techniques in pre-operative staging of early cervical carcinoma

PurposeDW-MRI parameters such as ADC hold the potential for more reliable staging of cervical cancer. We compared 2D region of interest (ROI) measurement techniques to 3D tumor analysis in the evaluation of ADC for cervical cancer. Secondly, we evaluated the utility of ADC for assessing parametrial and/or lymph node involvement. MethodThis prospective patient cohort registered cervical cancer patients who underwent pre-operative MRI with T1, T2W, and axial DWI. Retrospectively, two observers independently and blindly scored mean, minimum, and maximum ADC using three methods: a) 3D-Tumor analysis, b) single freehand ROI (2D-Slice), and c) single circular ROI (2D-Circle). Another observer scored parametrial and lymph node involvement on T1/T2W sequences. Parametrial and/or lymph node involvement were determined by surgical-pathologic results. The diagnostic performance of ADC for predicting the latter was evaluated by ROC curve, uni and multivariate analyses. ResultsOf 58 included patients, parametrial and/or lymph node involvement was found in 9 and 11 patients, respectively. Mean ADC (ADCMean) was least dependent on ROI technique, with interobserver variability (ICC: 0.88–0.90) and linear correlation (Pearson’s r: 0.95–0.96). To the contrary, minimal and maximal ADC were significantly influenced by 2D-ROI techniques. ADCMean was shown to be an independent predictor of parametrial (AUC: 0.80–0.86; OR: 16, 1.4–178) and/or lymph node involvement (AUC: 0.74–0.79; OR: 5.1, 1.1–24). ConclusionsSingle ROI measurements are a reliable method for determining ADCMean in cervical cancer. Second, ADCMean serves as a potential parameter for prediction of parametrial involvement prior to radical hysterectomy.

Application of diffusion-weighted MR imaging with ADC measurement for distinguishing between the histopathological types of sinonasal neoplasms

PurposeTo evaluate the potential contribution of quantitative DWI parameters including ADCmean and ADCratio values to help in distinguishing the histopathological types of sinonasal neoplasms. MethodsThis retrospective study included 83 patients (50 males, 33 females; mean age 61 years) with pathologically proven untreated sinonasal neoplasms who have undergone diffusion-weighted MRI imaging from February 2010 to August 2017. Diffusion-weighted MRI was performed on a 3 T unit with b factors of 0 and 1000 s/mm2, and ADC maps were generated. Mean ADC values of sinonasal tumors and ADC ratios (ADCmean of the tumor to ADCmean of pterygoid muscles) were compared with the histopathological diagnosis by utilizing the Kruskal-Wallis non-parametric test. ResultsMean ADCmean and ADCratio were 0.8 (SD, ±0.4) × (10−3 mm2/s) and 1.2 (SD, ±0.5), respectively, and each parameter was significantly different between histopathological types (p < 0.05). Mean ADCmean and ADCratio were higher in adenoid cystic carcinoma (ACC) than in SCC, lymphoma, neuroendocrine carcinoma and sinonasal undifferentiated carcinoma (SNUC) (p < 0.05). Optimized ADCmean thresholds of 0.79, 0.81, 0.74 and 0.78 (10−3 mm2/s) achieved maximal discriminatory accuracies of 100%, 79%, 100% and 89% for ACC/SNUC, ACC/SCC, ACC/neuroendocrine carcinoma, and ACC/lymphoma, respectively. ConclusionsThe optimized ADCmean threshold of 0.80 (10−3 mm2/s) could be used to differentiate ACC from non-ACC sinonasal neoplasms with maximal discriminatory accuracy (82%) and sensitivity of 100%. However, there is considerable overlapping of the ADCmean and ADCratio values among non-ACC sinonasal neoplasms hence surgical biopsy is still needed.

Preoperative diffusion-weighted magnetic resonance imaging and intraoperative frozen sections for predicting the tumor grade in endometrioid endometrial cancer.

ObjectiveThe histological tumor grade is a strong predictor of nodal metastasis in endometrial cancer; as such, an accurate pre- or intraoperative diagnosis is important for performing lymphadenectomy.MethodsNinety-one patients with endometrioid endometrial cancer were imaged on DW-MRI with the apparent diffusion coefficient (ADC) calculated and a frozen section (FS) diagnosis made before and at hysterectomy. The diagnostic accuracy for predicting the tumor grade for diffusion weighted magnetic resonance inaging (DW-MRI) and the FS diagnosis compared to the ultimate histologic status was analyzed.ResultsAmong 91 patients with endometrioid endometrial cancer, high-grade (endometrioid G3) tumors had lower ADC values than low-grade (endometrioid G1/2) tumors. The cut-off of the mean ADCmean values for predicting high-grade tumors resulted in 743×10-6 mm2/sec according to the receiver operating characteristic curve. The true positive rates of ADC values and FSs for the prediction of high-grade tumors did not differ to a statistically significant extent (73.3% vs. 66.7%, p=0.7), however, the true negative rate of ADC values for the prediction of low-grade tumors was significantly lower than that of the FSs (64.5% vs. 98.7%, p=0.01). The kappa statistics of ADC values and FSs were 0.23 and 0.73, respectively. Of note, all five patients with high-grade tumors for whom intraoperative FSs indicated low-grade tumors were predicted to have high-grade tumors on preoperative DW-MRI.ConclusionA FS diagnosis is more suitable for predicting high-grade tumors than DW-MRI; however, physicians should pay close attention to tumors with low ADC values on preoperative DW-MRI.

Sequential Apparent Diffusion Coefficient for Assessment of Tumor Progression in Patients with Low-Grade Glioma.

Early and accurate identification of tumor progression in patients with low-grade gliomas is challenging. We aimed to assess the role of quantitative ADC analysis in the sequential follow-up of patients with low-grade gliomas as a potential imaging marker of tumor stability or progression. In this retrospective study, patients with a diagnosis of low-grade glioma with at least 12 months of imaging follow-up were retrospectively reviewed. Two neuroradiologists independently reviewed sequential MR imaging in each patient to determine tumor progression using the Response Assessment in Neuro-Oncology criteria. Normalized mean ADC (ADCmean) and 10th percentile ADC (ADC10) values from FLAIR hyperintense tumor volume were calculated for each MR image and compared between patients with stable disease versus tumor progression using univariate analysis. The interval change of ADC values between sequential scans was used to differentiate stable disease from progression using the Fisher exact test. Twenty-eight of 69 patients who were evaluated met our inclusion criteria. Fifteen patients were classified as stable versus 13 patients as having progression based on consensus reads of MRIs and the Response Assessment in Neuro-Oncology criteria. The interval change of ADC values showed greater concordance with ultimate lesion disposition than quantitative ADC values at a single time point. The interval change in ADC10 matched the expected pattern in 12/13 patients with tumor progression (overall diagnostic accuracy of 86%, P <.001). On average, the ADC10 interval change predicted progression 8 months before conventional MR imaging. The interval change of ADC10 values can be used to identify progression versus stability of low-grade gliomas with a diagnostic accuracy of 86% and before apparent radiologic progression on conventional MR imaging.

MRI with DWI for the Detection of Posttreatment Head and Neck Squamous Cell Carcinoma: Why Morphologic MRI Criteria Matter.

Although diffusion-weighted imaging combined with morphologic MRI (DWIMRI) is used to detect posttreatment recurrent and second primary head and neck squamous cell carcinoma, the diagnostic criteria used so far have not been clarified. We hypothesized that precise MRI criteria based on signal intensity patterns on T2 and contrast-enhanced T1 complement DWI and therefore improve the diagnostic performance of DWIMRI. We analyzed 1.5T MRI examinations of 100 consecutive patients treated with radiation therapy with or without additional surgery for head and neck squamous cell carcinoma. MRI examinations included morphologic sequences and DWI (b=0 and b=1000 s/mm2). Histology and follow-up served as the standard of reference. Two experienced readers, blinded to clinical/histologic/follow-up data, evaluated images according to clearly defined criteria for the diagnosis of recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment, post-radiation therapy inflammatory edema, and late fibrosis. DWI analysis included qualitative (visual) and quantitative evaluation with an ADC threshold. Recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment was present in 36 patients, whereas 64 patients had post-radiation therapy lesions only. The Cohen κ for differentiating tumor from post-radiation therapy lesions with MRI and qualitative DWIMRI was 0.822 and 0.881, respectively. Mean ADCmean in recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment (1.097 ± 0.295 × 10-3 mm2/s) was significantly lower (P < .05) than in post-radiation therapy inflammatory edema (1.754 ± 0.343 × 10-3 mm2/s); however, it was similar to that in late fibrosis (0.987 ± 0.264 × 10-3 mm2/s, P > .05). Although ADCs were similar in tumors and late fibrosis, morphologic MRI criteria facilitated distinction between the 2 conditions. The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (95% CI) of DWIMRI with ADCmean < 1.22 × 10-3 mm2/s and precise MRI criteria were 92.1% (83.5-100.0), 95.4% (90.3-100.0), 92.1% (83.5-100.0), 95.4% (90.2-100.0), 19.9 (6.58-60.5), and 0.08 (0.03-0.24), respectively, indicating a good diagnostic performance to rule in and rule out disease. Adding precise morphologic MRI criteria to quantitative DWI enables reproducible and accurate detection of recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment.

MRI features of pediatric intracranial germ cell tumor subtypes

Intracranial germ cell tumors differ in histology and location, and require different clinical management strategies. We characterized the imaging features that may aid pre-operative differentiation of intracranial germinomas and non-germinomatous germ cell tumors (NGGCTs). This retrospective study analyzed 85 patients with intracranial germ cell tumors and adequate preoperative or pretreatment MRIs between 2000 and 2013 at our institution. Pretreatment MRI characteristics, apparent diffusion coefficient (ADC) values, tumor histopathology, and patient outcomes were compared. NGGCTs occurred in the pineal region and cerebral hemispheres more often than germinomas; all bifocal lesions were germinomas. NGGCTs (36.6 ± 17.0mm) were significantly larger than germinomas (25.7 ± 11.6mm; P = 0.002). The presence of pure solid tumor (45.5 vs. 20.0%, P = 0.033) and an infiltrative margin (20.0 vs. 3.3%, P = 0.035) were significantly more common in germinomas than NGGCTs. The presence of intratumoral T1 hyperintense foci (66.7 vs. 10.9%, P < 0.001) and moderate/marked enhancement (86.7 vs. 50.9%, P < 0.001) were significantly more common in NGGCTs than in germinomas. Mean ADCmean values (×10-3mm2/s) were significantly lower in germinomas (1.113 ± 0.415) than in NGGCTs (2.011 ± 0.694, P = 0.001). Combined a lack of T1 hyperintense foci and an ADCmean threshold value (1.143 × 10-3 mm2/s) had the highest specificity (91.3%) and positive predictive value (92.3%), while the combination of lack of a T1 hyperintensense foci, no/mild enhancement, and an ADCmean threshold value had 100% sensitivity and 100% negative-predictive value for discriminating germinomas from NGGCTs. Pre-operative conventional MRI characteristics and diffusion-weighted MRI help clinicians to assess patients with intracranial germ cell tumors. Tumor size, location, T1 hyperintense foci, intratumoral cystic components, tumor margin and enhancing patterns demonstrate contrast between germinomas and NGGCTs. Serum tumor markers and adjunctive combination with T1 hyperintensity and/or enhancing pattern with ADC offer potential in preoperative differentiating intracranial germinomas and NGGCTs.

OS3 - 187 Differentiating Radionecrosis from Tumor Progression Using IVIM perfusion Fraction in Brain Metastases Treated with Radiosurgery

Radiation necrosis occurs in 5-25% of patients who undergo stereotactic radiosurgery (SRS) for brain metastases. Intravoxel incoherent motion (IVIM) uses MRI diffusion-weighted imaging (DWI) to assess regional perfusion. We investigated the utility of IVIM to differentiate recurrent tumor from radionecrosis after SRS. Patients who had SRS and subsequent surgical resection of what was thought to be either tumor progression or necrosis were included. ROIs were contoured on the pre-operative post-Gd T1-weighted images and transferred to DWI images using automated co-registration. The perfusion fraction (f) was calculated using asymptotic fitting and the mean f (fmean), 90th percentile for f (f90), mean ADC (ADCmean) and 10th percentile for ADC (ADC10) were calculated. Pathology reports were used to identify the predominant feature (necrosis versus tumor). Nine patients with ten lesions were included. One lesion exhibited pure necrosis while the other nine were mixed; three were predominantly (&gt;75%) tumor, three predominantly necrosis, and three were equal parts of both. The perfusion fraction was significantly higher in cases with predominantly tumor compared to those with predominantly necrosis (fmean 0.10±0.01 vs 0.08±0.01, p=0.02 and f90 0.22±0.01 vs 0.14±0.02, p&lt;0.001). ADC did not differentiate tumor from necrosis (ADCmean 0.97±0.23 vs 1.02±0.36, p=0.8 and ADC10 0.53±0.29 vs 0.76±0.29, p=0.33). The IVIM perfusion fraction is useful in differentiating recurrent tumor from radionecrosis in brain metastases treated with SRS. This is the first study to evaluate IVIM against the gold standard (histopathology).

Diffusion-Weighted Imaging in Meningioma: Prediction of Tumor Grade and Association with Histopathological Parameters

OBJECTIVES: To analyze diffusion-weighted imaging (DWI) findings of meningiomas and to compare them with tumor grade, cell count, and proliferation index and to test a possibility of use of apparent diffusion coefficient (ADC) to differentiate benign from atypical/malignant tumors. METHODS: Forty-nine meningiomas were analyzed. DWI was done using a multislice single-shot echo-planar imaging sequence. A polygonal region of interest was drawn on ADC maps around the margin of the lesion. In all lesions, minimal ADC values (ADCmin) and mean ADC values (ADCmean) were estimated. Normalized ADC (NADC) was calculated in every case as a ratio ADCmean meningioma/ADCmean white matter. All meningiomas were surgically resected and analyzed histopathologically. The tumor proliferation index was estimated on Ki-67 antigen–stained specimens. Cell density was calculated. Collected data were evaluated by means of descriptive statistics. Analyses of ADC/NADC values were performed by means of two-sided t tests. RESULTS: The mean ADCmean value was higher in grade I meningiomas in comparison to grade II/III tumors (0.96 vs 0.80 × 10−3 mm2s−1, P = .006). Grade II/III meningiomas showed lower NADC values in comparison to grade I tumors (1.05 vs 1.26, P = .015). There was no significant difference in ADCmin values between grade I and II/III tumors (0.69 vs 0.63 × 10−3 mm2s−1, P = .539). The estimated cell count varied from 486 to 2091 (mean value, 1158.20 ± 333.74; median value, 1108). There were no significant differences in cell count between grade I and grade II/III tumors (1163.93 vs 1123.86 cells, P = .77). The mean level of the proliferation index was 4.78 ± 5.08%, the range was 1% to 18%, and the median value was 2%. The proliferation index was statistically significant higher in grade II/III meningiomas in comparison to grade I tumors (15.43% vs 3.00%, P = .001). Ki-67 was negatively associated with ADCmean (r = −0.61, P < .001) and NADC (r = −0.60, P < .001). No significant correlations between cell count and ADCmean (r = −0.20, P = .164) or NADC (r = −0.25, P = .079) were found.ADCmin correlated statistically significant with cell count (r = −0.44, P = .002) but not with Ki-67 (r = −0.22, P = .129). Furthermore, the association between ADCmin and cell count was stronger in grade II/III tumors (r = −0.79, P = .036) versus grade I meningiomas (r = −0.41, P = .008). An ADCmean value of less than 0.85 × 10−3 mm2s−1 was determined as the threshold in differentiating between grade I and grade II/III meningiomas (sensitivity 72.9%, specificity 73.1%, accuracy 73.0%). The positive and negative predictive values were 33.3% and 96.8%, respectively. The same threshold ADCmean value was used in differentiating between tumors with Ki-67 level ≥5% and meningiomas with low proliferation index (Ki-67 <5%). This threshold yielded a sensitivity of 70.6%, a specificity of 81.2%, and an accuracy of 77.6%. The positive and negative predictive values were 66.6% and 83.9%, respectively. CONCLUSIONS: Grade II/III tumors had lower ADCmean values than grade I meningiomas. ADCmean correlated negatively with tumor proliferation index and ADCmin with tumor cell count. These associations were different in several meningiomas. ADCmean can be used for distinguishing between benign and atypical/malignant tumors.

Correlation of the apparent diffusion coefficient (ADC) with the standardized uptake value (SUV) in lymph node metastases of non-small cell lung cancer (NSCLC) patients using hybrid 18F-FDG PET/MRI.

ObjectiveTo compare the apparent diffusion coefficient (ADC) in lymph node metastases of non-small cell lung cancer (NSCLC) patients with standardized uptake values (SUV) derived from combined 18F-fluoro-deoxy-glucose-positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI).Material and Methods38 patients with histopathologically proven NSCLC (mean age 60.1 ± 9.5y) received whole-body PET/CT (Siemens mCT™) 60min after injection of a mean dose of 280 ± 50 MBq 18F-FDG and subsequent PET/MRI (mean time after tracer injection: 139 ± 26 min, Siemens Biograph mMR). During PET acquisition, simultaneous diffusion-weighted imaging (DWI, b values: 0, 500, 1000 s/mm²) was performed. A maximum of 10 lymph nodes per patient suspicious for malignancy were analyzed. Regions of interest (ROI) were drawn covering the entire lymph node on the attenuation-corrected PET-image and the monoexponential ADC-map. According to histopathology or radiological follow-up, lymph nodes were classified as benign or malignant. Pearson’s correlation coefficients were calculated for all lymph node metastases correlating SUVmax and SUVmean with ADCmean.ResultsA total of 146 suspicious lymph nodes were found in 25 patients. One hundred lymph nodes were eligible for final analysis. Ninety-one lymph nodes were classified as malignant and 9 as benign according to the reference standard. In malignant lesions, mean SUVmax was 9.1 ± 3.8 and mean SUVmean was 6.0 ± 2.5 while mean ADCmean was 877.0 ± 128.6 x10-5 mm²/s in PET/MRI. For all malignant lymph nodes, a weak, inverse correlation between SUVmax and ADCmean as well as SUVmean and ADCmean (r = -0.30, p<0.05 and r = -0.36, p<0.05) existed.ConclusionThe present data show a weak inverse correlation between increased glucose-metabolism and cellularity in lymph node metastases of NSCLC patients. 18F-FDG-PET and DWI thus may offer complementary information for the evaluation of treatment response in lymph node metastases of NSCLC.

Multimodal Imaging for Early Functional Response Assessment of 90Y-/177Lu-DOTATOC Peptide Receptor Targeted Radiotherapy with DW-MRI and 68Ga-DOTATOC-PET/CT

The purpose of this study is to investigate the utility of contrast-enhanced magnetic resonance imaging (CE-MRI), diffusion-weighted MRI (DW-MRI), and (68)Ga-DOTATOC positron emission tomography/computer tomography ((68)Ga-DOTATOC PET/CT) in the assessment of response to loco-regional peptide receptor radiotherapy (PRRT) with (90)Y-/(177)Lu-DOTATOC in patients with hepatic metastases from gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). CE-MRI, DW-MRI, and (68)Ga-DOTATOC-PET/CT images were acquired before and 3months after one to two cycles of intra-arterial (90)Y-/(177)Lu-DOTATOC therapy in 14 patients (nine female, five male; mean age, 54 ± 9years; range, 41-69years) with hepatic metastases from GEP-NET. A total of 38 liver metastases were defined as target lesions for which the longest diameter, mean apparent diffusion coefficient (ADCmean) and maximum standardized uptake value (SUVmax) were assessed. Based on changes in size on follow-up imaging, target lesions were classified as responding (RL) or nonresponding (NRL). Relative changes in tumor size, ADCmean, and SUVmax were compared between the two subgroups. A total of 27 responding and 11 nonresponding lesions were successfully evaluated. Mean ADCmean increased significantly in RL (p = 0.011) as well as NRL (p = 0.025). A significant correlation was found between baseline ADCmean and both the percent ADCmean change (p = 0.033) and decrease in lesion size after therapy (diameter p = 0.006; volume p = 0.002). SUVmax of RL declined significantly by 24.1% (p = 0.014) and remained nearly unchanged in NRL. The change of SUVmax correlated significantly with the pretreatment SUVmax (p < 0.001) and the change in lesion diameter (p = 0.009). NRL with an ADCmean change >0.31 × 10(-3)mm(2)/s on first follow-up imaging showed a decrease in size in the long-term course. These results suggest that both DW-MRI and DOTATOC-PET imaging provide potential biomarkers for early assessment of treatment and stratification of therapy response, but that DW-MRI should be interpreted only in combination with SSTR expression and morphologic changes.

Correlation Between Standardized Uptake Value and Apparent Diffusion Coefficient of Neoplastic Lesions Evaluated With Whole-Body Simultaneous Hybrid PET/MRI

The purpose of this study was to assess the correlation between standardized uptake value (SUV) and apparent diffusion coefficient (ADC) of neoplastic lesions in the use of a simultaneous PET/MRI hybrid system. Twenty-four patients with known primary malignancies underwent FDG PET/CT. They then underwent whole-body PET/MRI. Diffusion-weighted imaging was performed with free breathing and a single-shot spin-echo echo-planar imaging sequence with b values of 0, 350, and 750 s/mm(2). Regions of interest were manually drawn along the contours of neoplastic lesions larger than 1 cm, which were clearly identified on PET and diffusion-weighted images. Maximum SUV (SUVmax) on PET/MRI and PET/CT images, mean SUV (SUVmean), minimum ADC (ADCmin), and mean ADC (ADCmean) were recorded on PET/MR images for each FDG-avid neoplastic soft-tissue lesion with a maximum of three lesions per patient. Pearson correlation coefficient was used to asses the following relations: SUVmax versus ADCmin on PET/MR and PET/CT images, SUVmean versus ADCmean, and ratio of SUVmax to mean liver SUV (SUV ratio) versus ADCmin. A subanalysis of patients with progressive disease versus partial treatment response was performed with the ratio of SUVmax to ADCmin for the most metabolically active lesion. Sixty-nine neoplastic lesions (52 nonosseous lesions, 17 bone metastatic lesions) were evaluated. The mean SUVmax from PET/MRI was 7.0 ± 6.0; SUVmean, 5.6 ± 4.6; mean ADCmin, 1.10 ± 0.58; and mean ADCmean, 1.48 ± 0.72. A significant inverse Pearson correlation coefficient was found between PET/MRI SUVmax and ADCmin (r = -0.21, p = 0.04), between SUVmean and ADCmean (r = -0.18, p = 0.07), and between SUV ratio and ADCmin (r = -0.27, p = 0.01). A similar inverse Pearson correlation coefficient was found between the PET/CT SUVmax and ADCmin. Twenty of 24 patients had previously undergone PET/CT; five patients had a partial treatment response, and six had progressive disease according to Response Evaluation Criteria in Solid Tumors 1.1. The ratio between SUVmax and ADCmin was higher among patients with progressive disease than those with a partial treatment response. Simultaneous PET/MRI is a promising technology for the detection of neoplastic disease. There are inverse correlations between SUVmax and ADCmin and between SUV ratio and ADCmin. Correlation coefficients between SUVmax and ADCmin from PET/MRI were similar to values obtained with SUVmax from the same-day PET/CT. Given that both SUV and ADC are related to malignancy and that the correlation between the two biomarkers is relatively weak, SUV and ADC values may offer complementary information to aid in determination of prognosis and treatment response. The combined tumoral biomarker, ratio between SUVmax and ADCmin, may be useful for assessing progressive disease versus partial treatment response.

Functional imaging of head and neck squamous cell carcinoma with diffusion-weighted MRI and FDG PET/CT: quantitative analysis of ADC and SUV

PurposeHead and neck squamous cell carcinoma (HNSCC) may cause a decreased apparent diffusion coefficient (ADC) on diffusion-weighted magnetic resonance imaging (DW MRI) and an increased standardized uptake value (SUV) on fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). We analysed the reproducibility of ADC and SUV measurements in HNSCC and evaluated whether these biomarkers are correlated or independent.MethodsThis retrospective analysis of DW MRI and FDG PET/CT data series included 34 HNSCC in 33 consecutive patients. Two experienced readers measured tumour ADC and SUV values independently. Statistical comparison and correlation with histopathology was done. Intra- and inter-observer agreement for ADC and SUV measurements was assessed.ResultsIntraclass correlation coefficient (ICC) analysis showed almost perfect reproducibility (>0.90) for ADCmean, ADCmin, SUVmax and SUVmean values for intra-observer and inter-observer agreement. Mean ADCmean and ADCmin in HNSCC were 1.05 ± 0.34 × 10−3 mm2/s and 0.65 ± 0.29 × 10−3 mm2/s, respectively. Mean SUVmean and mean SUVmax were 7.61 ± 3.87 and 12.8 ± 5.0, respectively. Although statistically not significant, a trend towards higher SUV and lower ADC was observed with increasing tumour dedifferentiation. Pearson’s correlation analysis showed no significant correlation between ADC and SUV measurements (r −0.103, −0.051; p 0.552, 0.777).ConclusionOur data suggest that ADC and SUV values are reproducible and independent biomarkers in HNSCC.

Correlation of the apparent diffusion coefficient value and dynamic magnetic resonance imaging findings with prognostic factors in invasive ductal carcinoma

To evaluate the correlation of the mean and minimal apparent diffusion coefficient values (ADC(mean) , ADC(minimal) ) and dynamic magnetic resonance imaging (MRI) findings with prognostic factors in invasive ductal carcinoma. A total of 107 women with invasive ductal cancer underwent breast MRI. The ADC(mean) and ADC(minimal) of the cancers were computed. MRI findings were retrospectively evaluated according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon: mass or nonmass type, mass shape, mass margin, nonmass distribution, and enhancement pattern. Histological records were reviewed for tumor size, lymph node metastasis, histologic grade, and expression of estrogen receptors (ER), progesterone receptors (PR), c-erbB-2(HER2), Ki-67, and epidermal growth factor receptors (EGFR). Correlations of ADC values and MR findings with prognostic factors were determined using the Mann-Whitney U-test and the Kruskal-Wallis test. The mean ADC(minimal) was 0.78 ± 0.24 (× 10⁻³ mm² /s), and the mean ADC(mean) was 1.01 ± 0.23 (× 10⁻³ mm² /s). There was a significant correlation of the ADC(mean) value with ER expression (P = 0.027) and HER2 expression (P = 0.018). There was no significant relationship between ADC(minimal) and prognostic factors or between ADC(mean) and traditional prognostic factors, PR, Ki-67 and EGFR. The majority of the mass type lesions were less than 5 cm in size and the majority of nonmass type lesions were more than 2 cm in size (P = 0.022). The margin of mass was significantly associated with lymph node metastasis (P = 0.031), ER expression (P = 0.013), PR expression (P = 0.036), HER2 expression (P = 0.019), and EGRF expression (P = 0.041). The rim internal enhancement was significantly correlated with Ki-67 expression (P = 0.008). The low ADC(mean) value was related to positive expression of ER and negative expression of HER2. A spiculated margin was related to a good prognosis, but rim enhancement was associated with a poor prognosis.