Use Of Apparent Diffusion Coefficient Research Articles

Assessing parotid gland function through diffusion weighted MRI during and post-radiotherapy in head and neck cancer patients

ObjectivesThe purpose of this study was to evaluate the usefulness of apparent diffusion coefficient (ADC) variation in irradiated parotid glands during and after 3D conformal radiotherapy (3DCRT). Materials and methodsThis study enrolled 15 head and neck cancer (HNC) patients who were treated with 3DCRT underwent diffusion weighted imaging (DWI) at rest and after gustatory stimulation in three time points as follows: before, during (one day after receiving the mean dose 26 Gy) and 6 months after the end of radiotherapy (RT). Salivary Ejection Fraction (SEF) data was also obtained from salivary gland scintigraphy (SGS) at the same three time points as MRI. Mean ADC at rest and after stimulation (ADCr, ADCs) and SEF were extracted from parotid region for three time points. Finally, SEF and changes of ADC over time at rest and after stimulation and in each time point were compared. ResultsDifference between mean ADCr before RT and during RT was not significant (p = 0.12). The ADCr values were significantly higher after RT than before RT (p = 0.003) and during RT (after dose 26 Gy) (p = 0.001). The difference between ADCr and ADCs in each time point showed that there is significant difference between ADCr and ADCs before RT (p = 0.005). Difference between these parameters after RT was also significant (p = 0.05). Non-significant difference (p = 0.21) between ADCr and ADCs during RT was observed. The result of SEF also was significantly lower after RT than during (p = 0.008) and before RT (p = 0.001). ConclusionMean ADC values could be used as a surrogate marker to characterize the parotid function in different stages of RT.

Approaches to Increase Early Detection and Positive Biopsy Rate of Nasal Natural Killer/T-Cell Lymphoma.

To develop methods for early detection of natural killer/T-cell lymphoma, nasal type (nasal NKTL) and to evaluate the use of apparent diffusion coefficient (ADC) measurements from diffusion-weighted imaging (DWI) for selecting biopsy sites to enhance the positive biopsy rate. The clinical data of 32 cases of nasal NKTL were retrospectively collected and analyzed. Cases were graded from 1 to 5 based on endoscopic and imaging findings. Biopsy methods included the superficial forceps method and deep incisional method. Data recorded included biopsy method, time to confirmed diagnosis, number of biopsies required, and ADC values of biopsy sites. Both endoscopic and MRI lesion severity did not affect biopsy outcomes (p = 0.8248, 0.7571). The deep incisional biopsy method had a significantly higher probability of yielding positive pathological results compared to the superficial clamping method [OR (95% CI) = 23.2143 (6.0448, 89.1513) (χ2 = 26.1089, p < 0.0001)]. The ADC value at the site with a positive biopsy result is significantly lower than at the site with a negative result (p = 0.0003). The diagnostic threshold for ADC value to predict a positive biopsy result was 0.603 × 10-3 mm2/s, with a Youden index of 0.43. Nasal NKTL has distinct characteristics distinguishing it from sinusitis and other tumors. Deep incision biopsy under general anesthesia is superior to the superficial method. The location of the positive sampling site can be guided by measuring the ADC value, and the optimal diagnostic threshold of this proposed method is 0.603 × 10-3 mm2/s. 4 Laryngoscope, 2024.

Usefulness of apparent diffusion coefficient values for distinguishing between squamous cell carcinoma and malignant salivary gland tumor of the head and neck.

The aim of the study was to assess the usefulness of apparent diffusion coefficient (ADC) values for differentiating between SCC and malignant salivary gland tumors of the head and neck. This retrospective cross-sectional study was conducted on 29 patients with SCCs and 10 patients with malignant salivary gland tumors who underwent pretreatment MRI of the head and neck. The minimum and average ADC values of the tumors were measured, with normalized tumor to spinal cord ADC ratios generated. Comparisons of ADC values and normalized ADC ratios between the two tumor types were performed using the unpaired t-test. The minimum and average ADC values and normalized average ADC ratios of SCCs (753.17 ± 214.47 × 10-6mm2/s, 848.79 ± 250.13 × 10-6mm2/s, and 0.92 ± 0.25, respectively) were significantly lower than those of malignant salivary gland tumors (1084.90 ± 242.60 × 10-6mm2/s, 1305.90 ± 270.99 × 10-6mm2/s, and 1.58 ± 0.31, respectively; all p < 0.001). A cutoff value of 1.31 for the normalized average ADC ratio was used to distinguish between SCCs and malignant salivary gland tumors and achieved an area under the curve of 0.93, sensitivity of 96.6%, specificity of 90%, and accuracy of 94.6%. ADC value measurement could help differentiate between SCCs and malignant salivary gland tumors.

Magnetic resonance imaging radiomic features for recurrent prostate cancer following proton radiation therapy-A pilot study.

The role of multiparametric MRI (mp-MRI) for postproton radiation evaluation is unclear. In this pilot study, we characterize the mp-MRI features using the Prostate Imaging-Reporting and Data System (PI-RADS) for recurrent prostate cancer (PCa) following proton radiation therapy. After obtaining IRB approval, we identified 163 consecutive cases who underwent MRI-fusion prostate biopsy at our institution from November 2017 to May 2020. This study evaluated patients with prostate cancer (PCa) with biochemical recurrence following proton radiation. Patients were excluded if they had grossly metastatic disease, metal fragments, implanted devices, or with surgically removed prostates. The mpMRI studies were reviewed in depth and scored by 2 fellowship-trained radiologists. Following MRI-fusion biopsy of lesions of interest (LOI), slides were read by fellowship-trained pathologists. We found 14 patients with 16 lesions who met the study inclusion criteria. The median age was 69 years (range 57-79) and median time to biochemical recurrence was 7.3 years (range 3-13). On post-treatment imaging, decreases in prostate size and diffusely decreased T2 signal intensity were observed, making the use of apparent diffusion coefficient (ADC) and early enhancement at dynamic contrast enhanced (DCE) imaging often necessary for diagnosis of disease recurrence. We identified a total of 16 lesions with PIRADS scores of 3 or higher. Of these lesions, there were 5 PIRADS 3 lesions (4/5 (80%) without prostate cancer), 7 PIRADS 4-5 lesions (6 (86%) had high risk Pca), and 4 lesions with unassigned PIRADS scores (100% had high risk cancers). Among the MRI variables, diffusion weighted imaging (DWI) heterogeneity had the strongest association with recurrence of PCa (P < 0.001). Results of our pilot study showed that the PIRADS scoring system in the postproton radiation therapy setting has some correlations with prostate cancer recurrence; However, the clinical value of these findings are unclear. While definitive PIRADS categorization of lesions demonstrated expected frequency of cancer consistent with the scoring system, all unassigned lesions also harbored malignancy suggesting a cautious approach to PIRADS scoring system in postproton radiation setting. The findings from this study may be validated using a larger cohort.

Role of apparent diffusion coefficient in assessment of loco-regional nodal spread in cancer rectum: correlative study with histopathological findings

BackgroundRectal cancer is associated with high morbidity and mortality rates. Preoperative assessment and detection of nodal metastasis are crucial for selecting a proper treatment plan. Diffusion-weighted imaging is considered to be a crucial functional imaging technique that can aid in determining the condition of lymph nodes. This study aimed to assess the diagnostic utility of MRI functional images by use of apparent diffusion coefficient in regional nodal assessment in rectal cancer.ResultsThis study included 54 patients including 29 males (53.7%) and 25 females (46.3%) presented with pathologically proven rectal cancer. Regarding rectal adenocarcinoma, functional MRI imaging using ADC values found to have a better sensitivity (86.24%) in detection of regional nodal metastasis than conventional morphological MRI criteria with 1.05 × 10−3 mm2/s was employed as cutoff value to distinguish metastatic from non-metastatic lymph nodes with statistically significant P value (< 0.001); nevertheless, regarding the accuracy there was no difference (68.52%). As regards mucinous and signet ring cell carcinoma, morphological assessment using conventional MRI sequences were found to have a better accuracy (72.96%) and sensitivity (57.69%) than ADC value, with the latter showed low statistically significant results (P- value < 0.201) in distinguishing metastatic and non-metastatic nodes. This could be explained by extremely high ADC values of nodes for these pathological types owing to their high mucin content.ConclusionsMRI functional imaging using ADC values can be utilized to distinguish metastatic from non-metastatic lymph nodes in rectal adenocarcinoma employing diagnostic accuracy of 86.52%. However, morphological assessment using conventional MRI was found to be better in assessment of regional lymph nodes at mucinous and signet ring rectal carcinoma.

Impact of apparent diffusion coefficient on prognosis of early hepatocellular carcinoma: a case control study

BackgroundWe investigated the usefulness of apparent diffusion coefficients (ADC) from diffusion-weighted images (DWI) obtained using magnetic resonance imaging (MRI) for prognosis of early hepatocellular carcinoma (HCC): Barcelona Clinic Liver Cancer (BCLC) stage 0 and A.MethodsWe enrolled 102 patients who had undergone surgical resection for early HCC: BCLC stage 0 and A, and calculated their minimum ADC using DWI-MRI. We divided patients into ADCHigh (n = 72) and ADCLow (n = 30) groups, and compared clinicopathological factors between the two groups.ResultsThe ADCLow group showed higher protein induced by vitamin K absence-II (PIVKA-II) levels (p = 0.02) compared with the ADCHigh group. In overall survival, the ADCLow group showed significantly worse prognosis than the ADCHigh group (p < 0.01). Univariate analysis identified multiple tumors, infiltrative growth, high PIVKA-II, and low ADC value as prognostic factors. Multivariate analysis identified infiltrative growth and low ADC value as an independent prognostic factor.ConclusionADC values can be used to estimate the prognosis of early HCC.

The role of diffusion-weighted MRI in characterization of intracranial cystic lesions

Background Diffusion-weighted imaging (DWI) is reliable in diagnosing intracranial cysts. However, sometimes, it could not give satisfactory diagnostic confidence. Objective To study the role of DWI in differentiation between intracranial cysts and the usefulness of apparent diffusion coefficient. Patients and methods This study included 40 patients of different age groups with intracranial cysts. All patients included were subjected to full history taking, clinical examination, laboratory investigations, routine MRI examination, DWI, and apparent diffusion coefficient map. Results Receiver operating characteristic curve was generated to identify inflammatory intra-axial lesions and to obtain the best sensitivity (80%), specificity (83.3%), positive predictive value (80%), and negative predictive value (83.3%). The relationship was significant (P&lt;0.028). Receiver operating characteristic curve to identify epidermoid and arachnoid cysts and to obtain the best sensitivity (100%), specificity (100%), positive predictive value (100%), and negative predictive value (100%). The relationship was significant (P=0.013). Conclusion DWI is perfect in differentiating between necrotic tumors and abscesses, benign and malignant intracranial cysts, and between arachnoid and epidermoid cysts. But it failed in differentiating between lower-grade and high-grade glioma.

Values of the apparent diffusion coefficient in the differential diagnosis of tumors of the posterior fossa in the pediatric population of Colombia

Introduction: Posterior fossa tumors are common in the pediatric population and require adequate characterization by means of structural magnetic resonance imaging (MRI) and advanced MRI techniques to achieve an appropriate therapeutic approach. Objectives: To determine the usefulness of apparent diffusion coefficient (ADC) values for the differential diagnosis of posterior fossa tumors in the pediatric population treated at a reference hospital in Bogotá D.C., Colombia. Materials and methods: Diagnostic accuracy study carried out in 28 pediatric patients diagnosed with posterior fossa tumor between 2017 and 2019 at the Fundación Hospital de la Misericordia, a quaternary care institution. ADC values were measured and compared with histopathological diagnosis as gold standard, obtaining sensitivity, specificity, and positive and negative predictive values. Differences between medians were determined using the Kruskall-Wallis test. The p value between the quantitative ADC value and the gold standard was calculated using Pearson's chi-squared test, with a significance level of p&lt;0.05. Results: The mean age of the participants was 83.9 months (SD=57 months), and 64.28% of them were boys. Medulloblastoma was the most frequent tumor (39.29%). For the diagnosis of medulloblastoma, an ADC value of 0.6210x10-³mm²/s was established, obtaining a sensitivity and specificity of 81.82% and 76.47%, respectively. For the diagnosis of pilocytic astrocytoma, an ADC of 1.03x10-³mm²/s was determined, with a sensitivity of 66.67% and a specificity of 89.40%. Conclusions: ADC value is useful to classify and differentiate posterior fossa tumors in the Colombian pediatric population, showing an inversely proportional relationship with the tumor grade.

Apparent Diffusion Coefficient and Other Preoperative Magnetic Resonance Imaging Features for the Prediction of Positive Surgical Margins in Prostate Cancer Patients Undergoing Radical Prostatectomy.

To investigate the use of apparent diffusion coefficient (ADC) values and other MRI features for predicting positive surgical margins (PSMs) in patients undergoing radical prostatectomy. We retrospectively identified 400 consecutive patients who underwent surgery for prostate cancer between January 2015 and June 2016. ADC values of the index lesion and other preoperative magnetic resonance imaging features, including tumor site, laterality, level, Prostate Imaging Reporting and Data System category, European Society of Urogenital Radiology extracapsular extension score, and prostate volume, were assessed. Univariate and multivariable logistic regression were performed. Performance in predicting the occurrence of PSMs was measured using the area under the curve (AUC). AUC differences were evaluated with the DeLong method. The Youden index was calculated to identify the ADC threshold to best discriminate patients with PSMs. Of the 400 patients, 105 (26.2%) had PSMs after radical prostatectomy. ADC values, Prostate Imaging Reporting and Data System category, extracapsular extension score, tumor site, and laterality were significantly associated with PSMs (P < .001) in univariate analysis. The AUC of the predictive model based on ADC alone was 68.2% (95% confidence interval, 62.2-74.2%) and did not significantly differ from the best multivariable predictive model which combined laterality, and site with ADC to attain an AUC of 70.0% (95% confidence interval, 64.2-75.8%; DeLong P=.318). The ADC threshold that maximized the Youden index was 960.3 µm2/s. ADC values and preoperative magnetic resonance imaging features can help estimate the risk of PSMs after radical prostatectomy.

Pretreatment Apparent Diffusion Coefficient Cannot Predict Histopathological Features and Response to Neoadjuvant Radiochemotherapy in Rectal Cancer: A Meta-Analysis

Aim: Our purpose was to perform a systemic literature review and meta-analysis regarding use of apparent diffusion coefficient (ADC) for prediction of histopathological features in rectal cancer (RC) and to prove if ADC can predict treatment response to neoadjuvant radiochemotherapy (NARC) in RC. Methods: MEDLINE library, EMBASE, Cochrane, and SCOPUS database were screened for associations between ADC and histopathology and/or treatment response in RC up to June 2020. Authors, year of publication, study design, number of patients, mean value, and standard deviation of ADC were acquired. The methodological quality of the collected studies was checked according to the Quality Assessment of Diagnostic Studies instrument. The meta-analysis was undertaken by using the RevMan 5.3 software. DerSimonian and Laird random-effects models with inverse-variance weights were used to account the heterogeneity between the studies. Mean ADC values including 95% confidence intervals were calculated. Results: Overall, 37 items (2,015 patients) were included. ADC values of tumors with different T and N stages and grades overlapped strongly. ADC cannot distinguish RC with a high- and low-carcinoembryonic antigen level. Regarding KRAS status, ADC cannot discriminate mutated and wild-type RC. ADC did not correlate significantly with expression of vascular endothelial growth factor and hypoxia-inducible factor 1a. ADC correlates with Ki 67, with the calculated correlation coefficient: −0.52. The ADC values in responders and nonresponders overlapped significantly. Conclusion: ADC correlates moderately with expression of Ki 67 in RC. ADC cannot discriminate tumor stages, grades, and KRAS status in RC. ADC cannot predict therapy response to NARC in RC.

The Diagnostic Accuracy of Magnetic Resonance Imaging for Maternal Acute Adnexal Torsion during Pregnancy: Single-Institution Clinical Performance Review.

Background: For acute adnexal torsion of pregnant women, appropriate treatment based on an accurate diagnosis is especially important for fertility preservation and timely treatment. The 2017 American College of Obstetricians and Gynecologists (ACOG) Committee Opinion No. 723 announced its practice-changing guidelines to ensure that diagnostic magnetic resonance imaging (MRI) conducted during the first trimester and gadolinium exposure at any time during pregnancy are safe for fetal stability. Unfortunately, few studies have been performed to evaluate the usefulness of the diagnostic accuracy of MRI for acute adnexal torsion during pregnancy. Objective: We sought to determine the efficacy of diagnostic MRI modality using multiparameter for maternal adnexal torsion during pregnancy. Methods: From 1 January 2007 to 31 January 2019, 131 pregnant with MRI tests were reviewed. In this retrospective cohort study, 94 women were excluded due to conditions other than an adnexal mass, and 37 were identified through MRI analyses conducted before surgery for suspected adnexal torsion. The primary outcome was the diagnostic accuracy of sonography and MRI, and the secondary outcome was the usefulness of Apparent diffusion coefficient (ADC) values for predicting the severity of hemorrhagic infarction between the medulla and cortex of the torsed ovarian parenchyma. Results: Our study demonstrates that in the diagnosis of adnexal torsion during pregnancy, the sensitivity, specificity, positive predictive value, and negative predictive value are 62.5%, 83.3%, 90.9%, and 45.5% for sonography and 100%, 77.8%, 90.5%, and 100% for MRI. MRI results in surgical-proven adnexal torsion patients revealed unilocular ovarian cysts (36.8% (7/19)), multilocular ovarian cysts (31.6% (6/19)), and near normal-appearing ovaries (31.6% (6/19)). Pathology in adnexal torsion revealed a corpus luteal ovarian cyst (63.2% (12/19)) and underlying adnexal pathology (46.8% (7/19)). Maternal adnexal torsion during pregnancy was more likely to occur in corpus luteal ovarian cysts than in underlying adnexal masses (odds ratio, 2.14; 95% confidence interval (CI), 0.428–10.738). MRI features for adnexal torsion were as follows: tubal wall thickness, 100% (19/19); ovarian stromal (medullary) edema, 100% (19/19); symmetrical or asymmetrical ovarian cystic wall, 100%(19/19); prominent follicles in the ovarian parenchyma periphery, 57.9% (11/19); periadenxal fat stranding, 84.2% (16/19); uterine deviation to the twisted side, 21.1% (4/19); and peritoneal fluid, 42.1% (8/19). The signal intensity of the ADC values of the ovarian medulla and cortex were compared between the cystectomy and detorsion (CD) and salpingo-oophorectomy (SO) groups. The ADC values of the CD and SO groups were 1.81 ± 0.09 × 10−3 mm2/s and 1.91 ± 0.18 × 10−3 mm2/s, respectively (P = 0.209), in the ovarian medulla and 1.37 ± 0.32 × 10−3 mm2/s and 0.96 ± 0.36 × 10−3 mm2/s, respectively (P = 0.022), in the ovarian cortex. The optimal cut-off value of ADC values for predictable total necrosis in the torsed ovarian cortex was ≤ 1.31 × 10−3 mm2/s (area under the curve (AUC) = 0.81; 95% CI 0.611–1.0; P = 0.028). Conclusion: Our data showed that maternal adnexal torsion during pregnancy occurred in most corpus luteal cystic ovary cases and some normal-appearing ovary during the 1st and 2nd trimesters of gestation. Therefore, this study is the first study to elaborate on the existence or usefulness of the diagnostic MRI for acute maternal adnexal torsion during pregnancy and to provide a predictive diagnosis of the severity of hemorrhagic infarction for deciding surgical radicality.

Clinical utility of apparent diffusion coefficient and diffusion‐weighted magnetic resonance imaging for resectability assessment of head and neck tumors with skull base invasion

The usefulness of apparent diffusion coefficient (ADC) and diffusion-weighted magnetic resonance imaging (DWI) in the detection of malignant tumors has been reported. The purpose of this study is to clarify the role of ADC and DWI for diagnosis of skull base tumors. A total of 27 patients with head and neck tumors with skull base invasions undergoing skull base surgery were enrolled in this study. Pathological findings of dural invasion and bone invasion were compared with the diagnostic imaging. Advanced magnetic resonance imaging techniques revealed that ADC values in regions of pathological bone and dural invasions were significantly lower than in regions of no invasion. The area under the curve of ADC in bone invasions and dural invasions were 0.957 and 0.894, respectively. Our findings indicate that ADC and DWI are useful tools for the diagnosis of head and neck tumors with skull base invasion.

Accuracy of ADC ratio in discriminating true and false positives in multiparametric prostatic MRI

PurposeOur goal was to evaluate the usefulness of apparent diffusion coefficient (ADC) ratios in discriminating true from false positives in multiparametric (mp) prostate MRI in clinical practice. MethodsWe retrospectively evaluated 98 prostate lesions in a series of 73 patients who had undergone prostate mpMRI and standard 12-core prostatic biopsy in our institution from 2016 to 2018. Two experienced radiologists performed double blind ADC value quantifications of both MRI-identified lesions and apparently benign contralateral prostatic parenchyma in a circular region of interest (ROI) of ∼10 mm2. The ratios between the mean values of both measurements (i.e., ADC ratio mean) and between the minimum value of the lesion and the maximum value of the benign parenchyma (i.e., ADC ratio min-max) were automatically calculated. The malignancy of all lesions was determined through biopsy according to Gleason score (GS ≥ 6) and localization. ResultsFor Reader 1, the area under the ROC curve (AUC) of ADC ratio mean and ADC ratio min-max were 0.72 and 0.67, respectively, whereas for Reader 2 these values were 0.74 and 0.71, respectively. The best cut-off values for ADC ratio means were ≥ 0.5 (Reader 1) and ≥ 0.6 (Reader 2), with a sensitivity of 76.3 % and 84.2 % and a specificity of 51.7 % and 50 %, respectively. Moreover, based on a threshold of 0.6, no clinically significant prostate cancer (csPCa) was missed by Reader 1, while only one went unnoticed by Reader 2. ConclusionThe ADC ratio is a useful and moderately accurate complementary tool to diagnose prostate cancer in the mp-MRI.

Diffusion‐weighted magnetic resonance imaging in the palatal tumors: Usefulness of apparent diffusion coefficient value for characterization of benign and malignant tumors

AbstractAimThe aim of this study was to investigate the diffusion‐weighted magnetic resonance imaging (DWI) in the palatal tumors, especially usefulness of apparent diffusion coefficient (ADC) value for characterization of benign and malignant tumors.Materials and MethodsTwenty‐four patients with palatal tumors (16 malignant tumors and 8 benign tumors) who underwent DWI for diagnosis of palatal lesions were included in this prospective study. DWI was performed on a 1.5 T unit, with b factor of 0 and 800 s/mm2; moreover, ADC maps were generated. ADC values were measured for the palatal tumors. The histopathological diagnoses were obtained by surgery in all cases. The ADC values of the palatal tumors were evaluated by one‐way repeated‐measures analysis of variance with Tukey's HSD test. A P value lower than .05 was considered as statistically significant.ResultsThe mean ADC value of squamous cell carcinoma (1.10 ± 0.11 × 10−3 mm2 s−1) was significantly lower than that of pleomorphic adenoma (1.49 ± 0.41 × 10−3 mm2 s−1, P = .046) and another benign tumor (1.85 ± 0.40 × 10−3 mm2 s−1, P = .000).ConclusionsADC value derived from DWI could be useful for the characterization of benign and malignant palatal tumors.

Can apparent diffusion coefficient (ADC) distinguish breast cancer from benign breast findings? A meta-analysis based on 13 847 lesions

BackgroundThe purpose of the present meta-analysis was to provide evident data about use of Apparent Diffusion Coefficient (ADC) values for distinguishing malignant and benign breast lesions.MethodsMEDLINE library and SCOPUS database were screened for associations between ADC and malignancy/benignancy of breast lesions up to December 2018. Overall, 123 items were identified. The following data were extracted from the literature: authors, year of publication, study design, number of patients/lesions, lesion type, mean value and standard deviation of ADC, measure method, b values, and Tesla strength.The methodological quality of the 123 studies was checked according to the QUADAS-2 instrument. The meta-analysis was undertaken by using RevMan 5.3 software. DerSimonian and Laird random-effects models with inverse-variance weights were used without any further correction to account for the heterogeneity between the studies. Mean ADC values including 95% confidence intervals were calculated separately for benign and malign lesions.ResultsThe acquired 123 studies comprised 13,847 breast lesions. Malignant lesions were diagnosed in 10,622 cases (76.7%) and benign lesions in 3225 cases (23.3%). The mean ADC value of the malignant lesions was 1.03 × 10− 3 mm2/s and the mean value of the benign lesions was 1.5 × 10− 3 mm2/s. The calculated ADC values of benign lesions were over the value of 1.00 × 10− 3 mm2/s. This result was independent on Tesla strength, choice of b values, and measure methods (whole lesion measure vs estimation of ADC in a single area).ConclusionAn ADC threshold of 1.00 × 10− 3 mm2/s can be recommended for distinguishing breast cancers from benign lesions.

Differentiation of Schmorl Nodes From Bone Metastases of the Spine: Use of Apparent Diffusion Coefficient Derived From DWI and Fat Fraction Derived From a Dixon Sequence

OBJECTIVE. The objective of our study was to evaluate the diagnostic performance of quantitative parameters derived from DWI and a Dixon MRI sequence in differentiating Schmorl nodes and bone metastases of the spine. MATERIALS AND METHODS. Fifty-one lesions (51 patients) were assessed with DWI and six-echo Dixon sequences for fat fraction (FF) quantification on 3-T MRI. The lesions were divided into two groups: Schmorl nodes (n = 22) and bone metastases (n = 29). The quantitative parameters of the lesions were obtained, including the apparent diffusion coefficient (ADC) value, FF, and FF ratio (defined as the FF of the lesion divided by the FF of normal marrow). The mean values of the parameters were compared between the two groups, and ROC curves were analyzed. For the ROC curves, AUCs were compared. RESULTS. The ADC value, FF, and FF ratio of bone metastases were significantly lower than those of Schmorl nodes (mean ADC value, 916.01 × 10-6 mm2/s vs 1569.78 × 10-6 mm2/s [p < 0.001]; mean FF, 2.89% vs 10.54% [p < 0.001]; mean FF ratio, 0.05 vs 0.21 [p < 0.001]). The ROC AUCs of the ADC value, FF, and FF ratio were 0.94, 0.95, and 0.97, respectively. The AUCs of all three imaging parameters did not show a statistically significant difference. CONCLUSION. ADC value, FF, and FF ratio can be useful for differentiating Schmorl nodes from bone metastases.

Added value of apparent diffusion coefficient in distinguishing between serous and mucin-producing pancreatic cystic neoplasms.

To evaluate the added value of diffusion-weighted imaging (DWI) on MRI in differentiating serous from mucin-producing pancreatic cystic neoplasms (PCNs). One hundred seventeen patients with PCN measuring ≥ 10mm were included. Three readers independently evaluated MRI with and without the use of apparent diffusion coefficient (ADC). Logistic regression was used to analyze whether confidence scores were different with the use of different image sets. Diagnostic performance with and without ADC was compared. DWI/ADC improved confidence in 44.8%, 73.6%, and 78.2% of patients by the three readers in distinguishing serous from mucin-producing PCNs. The use of ADC increased the probability of a higher confidence in the differentiation as compared to morphological imaging for all three readers (p < 0.001). Odds ratio for increase in the diagnostic confidence with the use of ADC for the three readers with decreasing years of experience were 5.8, 6.8, and 12.7. The diagnostic accuracy of morphological MRI with ADC was higher than that without ADC for two of three readers with lesser experience (87.2% vs. 80.8%; 91.5% vs. 80.8%). DWI may have added value as a complementary tool to conventional morphological MRI in differentiating between serous and mucin-producing PCNs with possibly greater value for readers with less experience in reading abdominal MRI. • Optimal management of PCNs requires differentiation of serous from mucin-producing PCNs. • ADC measurements allow increased confidence in differentiating serous from mucin-producing PCNs. • ADC measurements increase the accuracy in diagnosing serous versus mucin-producing PCNs.

MRI-Based Apparent Diffusion Coefficient for Predicting Pathologic Response of Rectal Cancer After Neoadjuvant Therapy: Systematic Review and Meta-Analysis.

The purpose of this study was to assess the use of apparent diffusion coefficient (ADC) during DWI for predicting complete pathologic response of rectal cancer after neoadjuvant therapy. A systematic review of available literature was conducted to retrieve studies focused on the identification of complete pathologic response of locally advanced rectal cancer after neoadjuvant chemoradiation, through the assessment of ADC evaluated before, after, or both before and after treatment, as well as in terms of the difference between pretreatment and posttreatment ADC. Pooled mean pretreatment ADC, posttreatment ADC, and Δ-ADC (calculated as posttreatment ADC minus pretreatment ADC divided by pretreatment ADC and multiplied by 100) in complete responders versus incomplete responders were calculated. For each parameter, we also pooled sensitivity and specificity and calculated the area under the summary ROC curve. We found 10 prospective and eight retrospective studies. Overall, pathologic complete response was observed in 22.2% of patients. Pooled mean pretreatment ADC in complete responders was 0.84 × 10-3 mm2/s versus 0.89 × 10-3 mm2/s in incomplete responders (p = 0.33). Posttreatment ADC values were 1.51 × 10-3 mm2/s and 1.29 × 10-3 mm2/s, in complete and incomplete responders, respectively (p = 0.00001). The Δ-ADC percentages were also significantly higher in complete responders than in incomplete responders (59.7% vs 29.7%, respectively, p = 0.016). Pooled sensitivity, specificity, and AUC were 0.743, 0.755, and 0.841 for pretreatment ADC; 0.800, 0.737, and 0.782 for posttreatment ADC; and 0.832, 0.806, and 0.895 for Δ-ADC. Use of ADC during DWI is a promising technique for assessment of results of neoadjuvant treatment of rectal cancer.

Usefulness of Apparent Diffusion Coefficient of Diffusion-Weighted Imaging for Differential Diagnosis of Primary Solid and Cystic Renal Masses.

SummaryBackgroundTo evaluate the value of diffusion-weighted imaging (DWI) for distinguishing between benign and malignant renal masses.Material/MethodsSeventy-five patients with 75 unilateral renal lesions were included, and 75 normal contralateral kidneys served as controls. The lesions were categorized into four groups as malignant cystic, malignant solid, benign cystic and benign solid. The apparent diffusion coefficients (ADCs) were evaluated for two different b values (b=600 s/mm2 and b=1000 s/mm2). Receiving operating characteristic analysis was performed to identify threshold ADCs.ResultsSensitivity and specificity were 67% and 77% (p=0.003) at the cutoff value of 1.5 for b=600 s/mm2, and 79% and 62% (p=0.004) at the cutoff value of 1.99 for b=1000 s/mm2 as regards the differentiation between solid benign and malignant renal lesions. Sensitivity and specificity were 78% and 79% (p=0.001) at the cutoff value of 3.1 for b=600 s/mm2, and 86% and 61% (p=0.003) at the cutoff value of 2.9 for b=1000 s/mm2 as regrads the differentiation between benign and malignant cystic renal lesions.ConclusionsDWI can be an effective diagnostic method for distinguishing between benign and malignant renal masses.

Usefulness of apparent diffusion coefficient value and proton magnetic resonance spectroscopy as a noninvasive techniques in recurrent cerebral gliomas

ObjectiveConventional MRI does not provide sufficient information to differentiate post-radiotherapy necrosis from brain tumor recurrence, recent studies have investigated the use of more advanced imaging modalities that are able to differentiate between the two entities. Aim of the studyTo assess the usefulness of combined apparent diffusion coefficient (ADC) value and single voxel spectroscopy (SVS) in the differentiation between recurrent brain gliomas and post-radiotherapy necrosis. MethodsTwenty-two patients with suspected tumor recurrence after surgical resection and radiotherapy treatment were included in our study. MRI with contrast, diffusion weighted MRI with ADC value and MR spectroscopy were done to all patients. ResultsADC values were ≤1.150 × 10−3 mm2/sec for recurrent high grade gliomas, >1.150–≤1.370 × 10−3 mm2/sec for recurrent low grade gliomas and >1.370 × 10−3 mm2/sec for post radiation necrosis. NAA/Cr ratio could significantly differentiate between recurrent gliomas and post radiation necrosis (p value = .019), also Cho/Cr was significant p value = .006. Also NAA/Cr and Cho/Cr were statistically significant in differentiating recurrent high grade from low grade gliomas (p value < .001). ConclusionCombination of calculated ADC value and MR spectroscopy added more information and increase the accuracy of conventional MR imaging in the differentiation of patients with suspected recurrent brain glioma from post-radiotherapy necrosis.