Echo-planar Diffusion-weighted Magnetic Resonance Imaging Research Articles

Relevance of lesion size in navigator-triggered and free-breathing diffusion-weighted liver MRI.

The purpose of this study was to investigate the relevance of focal liver lesions (FLL) size for lesion detection comparing navigator triggering (TRIG) to free breathing (FB) liver Diffusion-weighted magnetic resonance imaging (DWI). Patients with known or suspected FLL were prospectively (registry number 276_19 B) included from October to December 2019 in this study, out of which 32 had liver lesions. Echo planar spin-echo DWI data both with TRIG and FB were with approximately constant acquisition times acquired at 1.5 T. Lesions were segmented in the b = 800 s/mm² images in both the TRIG and FB images. The lesion size, location (liver segment), liver lesion visibility, as well as contrast-to-noise ratio (CNR) were recorded. The CNR was assessed with the Wilcoxon-Mann-Whitney test and the number of visible lesions with the Fisher test. Data from 43 patients (22 female) were analyzed. The mean patient age was 58 ± 14 years. A total of 885 FLL (Ntotal) were segmented. Among these, 811 lesions (Nboth) were detected with TRIG and FB, 65 lesions exclusively with TRIG (NTRIG_Only), and nine exclusively in FB (NFB_Only). The largest additional lesion in TRIG/FB had a diameter of 10.4 mm/7.6 mm. The number of additional lesions detected with TRIG decreased with size. Among all lesions ≤ 4.7 mm, the relative number of additional lesions was 15.6%. Additional lesions were found in all liver segments with TRIG. In the left liver lobe, the relative proportion was 9.2%, and in the right liver lobe 5.4%. CNR and visibility were significantly higher in TRIG than in FB (p < 0.001). In relation to size, the difference is significant in terms of visibility and CNR for lesion diameters ≤ 8 mm. Respiration triggering can improve the detection of small liver lesions with diameters up to approx. 1 cm in the whole liver. Question Can respiration triggering (TRIG) improve the detection of small FLL compared to FB diffusion-weighted imaging? Findings Among 885 segmented FLL, TRIG was superior to FB for lesions smaller than 8 mm and had improved CNR and visibility. Clinical relevance Diffusion-weighted magnetic resonance imaging is used for the detection of focal liver lesions and image quality is influenced by breathing motion. Navigator triggering becomes more important for smaller lesions, and seems recommendable for the detection of small focal liver lesions.

The Evaluation of Zoomed Echo-Planar Diffusion-Weighted Magnetic Resonance Imaging With Two-dimensional Spatial-Selective Radiofrequency Excitation Pulses in Patients With Hilar Cholangiocarcinoma.

BackgroundWe aimed to investigate the feasibility and application of using the zoomed diffusion-weighted echo-planar imaging (z-EPI DWI) sequences for hilar cholangiocarcinoma assessment compared with conventional single-shot EPI diffusion-weighted imaging (c-EPI DWI).MethodsBoth c-EPI DWI and z-EPI DWI were preoperatively performed in 16 patients with histopathologically-confirmed hilar cholangiocarcinoma. A two-dimensional spatial-selective radiofrequency (RF) pulse was applied to the z-EPI DWI using an echo-planar transmit trajectory. Anatomic structural visualization, lesion conspicuity, artifact presence and overall image quality were evaluated and compared between the two sequence images. The ratio of differences regarding hilar cholangiocarcinoma lesion sizes measured on T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) were compared from both EPI techniques. The DW images for tumor involvement of the bile duct were reviewed based on histopathological examination of the surgical intraoperative evaluation. ADC measurements of DWIs in the hilar cholangiocarcinoma lesions were conducted.ResultsThe hepatic hilar region was better delineated by visualization of anatomical structures, lesion conspicuity and overall image quality using the z-EPI DWI and these analyses were compared with the c-EPI DWI method (all p<0.05). Better lesion delineation of bile duct walls and lumens was noted in four patients with z-EPI DWI compared with those of c-EPI DWI. No significant differences were noted between the two image datasets for artifacts (p=0.876). The ratio of differences regarding hilar cholangiocarcinoma lesion sizes was significantly lower (p= 0.018) on T2WI and DWI, as determined by the z-EPI DWI than that determined by the c-EPI method. The use of z-EPI DWI resulted in the accurate diagnosis of the Bismuth-Corlette classification of 15 tumors (15/16, 93.75%), whereas the use of c-EPI DWI resulted in correct diagnosis of 12 tumors (12/16, 75.00%). There were no significant differences between c-EPI DWI and z-EPI DWI in the ADC values of hilar cholangiocarcinoma lesions (p= 0.48).Conclusionz-EPI DWI resulted in remarkable image quality improvements for hilar cholangiocarcinoma. The ability to detect and delineate lesions using z-EPI DWI was superior to that of c-EPI DWI.

Is diffusion-weighted magnetic resonance imaging (DW-MRI) a requirement for suspected cholesteatoma in patients to undergo primary surgery?

Aim: In this study, the aim was to investigate the correlation of preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) with postoperative pathology findings in patients undergoing tympanomastoidectomy with suspicion of primary cholesteatoma. Materials and Methods: The study consisted of the retrospective evaluation of preoperative MRIs, surgical findings and pathology results of patients who underwent tympanomastoidectomy and had preoperative DW-MRI at the Department of Otorhinolaryngology between the years 2017 and 2019. Results: The study was conducted with 199 patients who underwent tympanomastoidectomy surgery. A retrospective examination of patient files revealed that 80 (40.2%) of the patients underwent echoplanar diffusion-weighted magnetic resonance imaging (DW-MRI) because of suspected cholesteatoma in the preoperative period. Of these 80 patients, cholesteatoma was detected in 22 (27.5%) as a result of pathological analysis and/or surgery, but no diffusion restriction was found in MRI interpretation; in 44 (55%) of them, both cholesteatoma in pathological analysis and/or surgery and diffusion restriction in MRI interpretation were detected. In 10 (12.5%) of these 80 patients, cholesteatoma was not detected either in the MRI interpretation or in the pathological analysis and/or surgery. In the remaining 4 (5%) patients, there was a cholesteatoma suspicion in MRI, but it was not detected as a result of pathological analysis or surgery. In this study, the sensitivity of MRI for the diagnosis of cholesteatoma was 66.6%, and its specificity was 71.4%. Conclusion: MRI provides moderately (66.6%) reliable information in the diagnosis of cholesteatoma patients. However, it is more reliable (71.4%) when it comes to exclusion of the disease. Therefore, it should not be used as the sole determining factor in patients who will undergo primary surgery with suspected cholesteatoma. As much as our study results provide guidance for a more accurate use of imaging methods, series with higher numbers of patients are needed.

Diagnostic Accuracy of Echo-planar Diffusion-weighted Imaging in the Diagnosis of Intra-cerebral Abscess by Taking Histopathological Findings as the Gold Standard.

ObjectiveTo determine the diagnostic accuracy of echo-planar diffusion-weighted imaging (DWI) in the diagnosis of intra-cerebral abscesses by taking histopathological findings as the gold standard.Subject and methodsA retrospective cross-sectional study was performed from July 2014 to June 2015 at a tertiary care hospital in Karachi. A total of 462 patients, who were referred for magnetic resonance imaging (MRI) brain, presenting with clinical suspicion of an intra-cerebral abscess on the basis of clinical signs and symptoms, were included in this study. MR imaging was performed. All patients subsequently underwent surgery. The histopathological findings of these patients were collected and compared with echo-planar diffusion-weighted MRI findings. A proforma was used to record the findings.ResultsThe mean age of the patients was 47.39±13.54 years. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of echo-planar diffusion-weighted MRI in the diagnosis of intra-cerebral abscesses was 85.64%, 95.88%, 93.82%, 90.14%, and 91.56%, respectively.ConclusionBrain abscesses and necrotic tumors are, most of the time, difficult to differentiate on routine conventional imaging, and prompt diagnosis is important, as an untreated brain abscess could be lethal. Diffusion imaging can aid in the diagnosis and further management plan so as to help in improved patient care. Although this sequence has high sensitivity and specificity, it should be used in addition to conventional imaging and not as a replacement of histopathology.

Prediction of malignancy of submandibular gland tumors with apparent diffusion coefficient.

This study was performed to predict malignancy of submandibular gland tumors using the apparent diffusion coefficient (ADC). In total, 31 patients (19 male, 12 female; age, 16-71years) with solid submandibular gland tumors were retrospectively analyzed. All patients underwent single-shot echo-planar diffusion-weighted magnetic resonance imaging of the submandibular gland region. ADC maps of the submandibular gland were reconstructed. The ADC value of the submandibular gland tumors was calculated. A freehand region of interest encompassing the homogenous tumor and solid part of the heterogeneous tumor was established. The mean ADC for submandibular gland malignancy (1.15 ± 0.09 × 10-3 mm2/s) was significantly lower than that for benignancy (1.55 ± 0.25 × 10-3 mm2/s, P = 0.001). An ADC of 1.26 × 10-3 mm2/s could predict malignancy of submandibular gland tumors with an area under the curve of 0.869, accuracy of 84%, sensitivity of 88%, and specificity of 81%. The ADC is a noninvasive imaging parameter that can be used for prediction of malignancy of submandibular gland tumors.

Transcanal Endoscopic Ear Surgery for Middle Ear Cholesteatoma.

To evaluate the clinical parameters, outcomes, and complications of transcanal endoscopic ear surgeries for middle ear cholesteatoma. Retrospective study. Tertiary university-affiliated medical center. Adult patients (age >18) who underwent transcanal endoscopic ear surgeries for cholesteatoma, between March 2009 and March 2015. Transcanal endoscopic surgery was indicated when the cholesteatoma did not extend posterior to the anterior limb of the lateral semicircular canal. Rigid endoscopes 4 and 2.7 mm in diameter, 0, 30, 45, and 70 degrees were used with angled picks, suction, and forceps.Preoperative assessment included high-resolution computed tomography of the temporal bones and/or non echo-planar diffusion-weighted magnetic resonance imaging and pure-tone audiometry. Residual or recurrent disease was diagnosed by clinical examination and/or magnetic resonance imaging findings consistent with cholesteatoma. Intra- and postoperative complications, pre- and postoperative audiometric results were recorded. Sixty operations (56 patients, mean age = 43.6) were included.Six operations (10%) were performed under local anesthesia. The most common sites of cholesteatoma involvement were: posterior epitympanum (n = 51, 91%), anterior epitympanum (n = 19, 33.9%), posterior mesotympanum (n = 13, 23.2%), and sinus tympani (n = 11, 19.6%). Intraoperative ossicular chain reconstruction was performed in 18 (30%) cases.Our overall residual and recurrence rates were 10% (n = 6) and 8.3% (n = 5), respectively, with mean duration of follow up of 35 months. The most common sites of residual disease were the mastoid cavity/antrum (n = 3, 50%), tympanic cavity, and posterior mesotympanum. Overall minor and major complication rates were 16.6 and 6%, respectively. Transcanal endoscopic ear surgery was found to be an acceptable and safe technique for the exposure and eradication of middle ear and/or attic cholesteatoma.

Apparent Diffusion Coefficient Measurement in Mediastinal Lymphadenopathies: Differentiation between Benign and Malignant Lesions.

Objectives:We aimed to prospectively assess the diagnostic value of apparent diffusion coefficient (ADC) measurement in the differentiation of benign and malignant mediastinal lymphadenopathies.Materials and Methods:The study included 63 consecutive patients (28 women, 35 men; mean age 59.3 years) with 125 mediastinal lymphadenopathies. Echoplanar diffusion-weighted magnetic resonance imaging of the mediastinum was performed with b-factors of 0 and 600 mm2/s before mediastinoscopy and mediastinotomy, and ADC values were measured. The ADC values were compared with the histological results, and statistical analysis was done. P < 0.05 was considered statistically significant.Results:The mean ADC value of malignant mediastinal lymphadenopathy (1.030 ± 0.245 × 10−3 mm2/s) was significantly lower (P < 0.05) when compared to benign lymphadenopathies (1.571 ± 0.559 × 10−3 mm2/s). For differentiating malignant from benign mediastinal lymphadenopathy, the best result was obtained when an ADC value of 1.334 × 10−3 mm2/s was used as a threshold value; area under the curve 0.848, accuracy 78.4%, sensitivity 66%, specificity of 86%, positive predictive value 76.7%, and negative predictive value of 79.2%. Interobserver agreement was excellent for ADC measurements.Conclusions:ADC measurements could be considered an important supportive method in differentiating benign from malignant mediastinal lymphadenopathies.

Apparent Diffusion Coefficient Measurement in Mediastinal Lymphadenopathies: Differentiation between Benign and Malignant Lesions

Objectives: We aimed to prospectively assess the diagnostic value of apparent diffusion coefficient (ADC) measurement in the differentiation of benign and malignant mediastinal lymphadenopathies. Materials and Methods: The study included 63 consecutive patients (28 women, 35 men; mean age 59.3 years) with 125 mediastinal lymphadenopathies. Echoplanar diffusion-weighted magnetic resonance imaging of the mediastinum was performed with b-factors of 0 and 600 mm2/s before mediastinoscopy and mediastinotomy, and ADC values were measured. The ADC values were compared with the histological results, and statistical analysis was done. P < 0.05 was considered statistically significant. Results: The mean ADC value of malignant mediastinal lymphadenopathy (1.030 ± 0.245 × 10−3 mm2/s) was significantly lower (P < 0.05) when compared to benign lymphadenopathies (1.571 ± 0.559 × 10−3 mm2/s). For differentiating malignant from benign mediastinal lymphadenopathy, the best result was obtained when an ADC value of 1.334 × 10−3 mm2/s was used as a threshold value; area under the curve 0.848, accuracy 78.4%, sensitivity 66%, specificity of 86%, positive predictive value 76.7%, and negative predictive value of 79.2%. Interobserver agreement was excellent for ADC measurements. Conclusions: ADC measurements could be considered an important supportive method in differentiating benign from malignant mediastinal lymphadenopathies.

Diffusion-weighted Magnetic Resonance Imaging as a Novel Imaging Modality in Assessing Treatment Response in Necrotizing Otitis Externa.

To report our initial experience of diffusion-weighted magnetic resonance imaging (DW-MRI) as a novel imaging tool for assessing and monitoring treatment response in necrotizing otitis externa (NOE). Seven adults with a diagnosis of NOE on both clinical and computed tomography (CT) criteria who were subsequently monitored with at least two echoplanar DW-MRI investigations were included in this retrospective longitudinal observational study. Patients underwent magnetic resonance imaging (MRI), including echoplanar diffusion-weighted sequences, within 2 weeks of diagnosis of NOE to determine the extent of infection and to provide a baseline scan for monitoring response to treatment. Repeated imaging was undertaken after the agreed initial course of antimicrobial therapy was completed. The primary outcome measure for complete treatment response was complete resolution of high inflammatory signal on the DW-MRI apparent diffusion coefficient (ADC) map. This was correlated to clinical, biochemical, and other MRI measures of disease resolution. Baseline DW-MRI was carried out in all but one patient within 2 weeks of the initial diagnostic CT scan. Patients had between one and three further DW-MRI scans, at a mean interval of 4.4 months from the initial scan (range, 2-8 months). The decision to terminate or continue therapy correlated with ADC signal findings on DW-MRI in all cases. In comparison, conventional MRI sequences performed less well, as there was some degree of persistent residual soft tissue changes in all cases.

A Systematic Review of Non-Echo Planar Diffusion-Weighted Magnetic Resonance Imaging for Detection of Primary and Postoperative Cholesteatoma.

To investigate the diagnostic value of non-echo planar diffusion-weighted magnetic resonance imaging (DW-MRI) for primary and recurrent/residual (postoperative) cholesteatoma in adults (≥18 years) after canal wall up surgery. We conducted a systematic search in PubMed, Embase, and Cochrane up to October 22, 2014. All studies investigating non-echo planar DW-MRI for primary and postoperative cholesteatoma were selected and critically appraised for relevance and validity. In total, 779 unique articles were identified, of which 23 articles were included for critical appraisal. Seven articles met our criteria for relevance and validity for postoperative cholesteatoma. Four studies were additionally included for subgroup analysis of primary cases only. Ranges of sensitivity, specificity, positive predictive value, and negative predictive value yielded 43%-92%, 58%-100%, 50%-100% and 64%-100%, respectively. Results for primary subgroup analysis were 83%-100%, 50%-100%, 85%-100%, and 50%-100%, respectively. Results for subgroup analysis for only postoperative cases yielded 80%-82%, 90%-100%, 96%-100%, 64%-85%, respectively. Despite a higher prevalence of cholesteatoma in the primary cases, there was no clinical difference in added value of DW-MRI between primary and postoperative cases. We found a high predictive value of non-echo planar DW-MRI for the detection of primary and postoperative cholesteatoma. Given the moderate quality of evidence, we strongly recommend both the use of non-echo planar DW-MRI scans for the follow-up after cholesteatoma surgery, and when the correct diagnosis is questioned in primary preoperative cases.

Value of Echo-Planar Diffusion-Weighted Magnetic Resonance Imaging for Detecting Tympanomastoid Cholesteatoma.

The aim of this study was to evaluate the diagnostic accuracy of echo-planar diffusion-weighted magnetic resonance imaging (EP-DWI) and high-resolution computed tomography (HRCT) in the detection and localization of cholesteatoma. Fifty-four patients were prospectively included in this study. Patients with suspected primary or residual cholesteatoma were evaluated by EP-DWI and HRCT before tympanomastoid surgery. Radiological findings were correlated with intraoperative findings. EP-DWI and HRCT accurately predicted the presence or absence of cholesteatoma in 49 of 54 (90.7%) and 37 of 54 (68.5%) patients, respectively. The sensitivity, specificity, and positive and negative predictive values of EP-DWI were 88.4%, 92.8%, 92%, and 89.6%, respectively. However, sensitivity, specificity, and positive and negative predictive values of HRCT were 69%, 67.8%, 66.6%, and 73.07%, respectively. This study demonstrates that EP-DWI is more reliable in predicting the presence and localization of cholesteatoma compared with HRCT, before tympanomastoid surgery.

Diffusion-weighted imaging in the head and neck region: usefulness of apparent diffusion coefficient values for characterization of lesions.

We aimed to evaluate the role of apparent diffusion coefficient (ADC) values calculated from diffusion-weighted imaging for head and neck lesion characterization in daily routine, in comparison with histopathological results. Ninety consecutive patients who underwent magnetic resonance imaging (MRI) at a university hospital for diagnosis of neck lesions were included in this prospective study. Diffusion-weighted echo-planar MRI was performed on a 1.5 T unit with b factor of 0 and 1000 s/mm2 and ADC maps were generated. ADC values were measured for benign and malignant whole lesions seen in daily practice. The median ADC value of the malignant tumors and benign lesions were 0.72×10-3 mm2/s, (range, 0.39-1.51×10-3 mm2/s) and 1.17×10-3 mm2/s, (range, 0.52-2.38×10-3 mm2/s), respectively, with a significant difference between them (P < 0.001). A cutoff ADC value of 0.98×10-3 mm2/s was used to distinguish between benign and malignant lesions, yielding 85.3% sensitivity and 78.6% specificity. The median ADC value of lymphomas (0.44×10-3 mm2/s; range, 0.39-0.58×10-3 mm2/s) was significantly smaller (P < 0.001) than that of squamous cell carcinomas (median ADC value 0.72×10-3 mm2/s; range, 0.65-1.06×10-3 mm2/s). There was no significant difference between median ADC values of inflammatory (1.13×10-3 mm2/s; range, 0.85-2.38×10-3 mm2/s) and noninflammatory benign lesions (1.26×10-3 mm2/s; range, 0.52-2.33×10-3 mm2/s). Diffusion-weighted imaging and the ADC values can be used to differentiate and characterize benign and malignant head and neck lesions.

Correlation of computed tomography, echo-planar diffusion-weighted magnetic resonance imaging and surgical outcomes in middle ear cholesteatoma

Conclusion: Echo-planar diffusion-weighted magnetic resonance imaging (DW MRI) is more reliable than high-resolution computed tomography (HRCT) in predicting the presence and localization of cholesteatoma before tympanomastoid surgery. Objectives: To evaluate the diagnostic accuracy of HRCT and echo-planar DW MRI in the detection and localization of cholesteatoma. Methods: Fifty-nine patients were prospectively included in this study. Patients with suspected primary cholesteatoma were evaluated by HRCT and echo-planar DW MRI before tympanomastoid surgery. Radiological findings were correlated with intraoperative findings. Results: HRCT and echo-planar DW MRI accurately predicted the presence or absence of cholesteatoma in 40/59 (67.8%) and 52/59 (88.1%) patients, respectively. The sensitivity, specificity, and positive and negative predictive values of HRCT were 68.97%, 66.67%, 66.67%, and 68.97%, respectively. However, sensitivity, specificity, and positive and negative predictive values of echo-planar DW MRI were 85.71%, 90.32%, 88.89%, and 87.50%, respectively.

A study of the relationship between gender/age and apparent diffusion coefficient values in spleen of healthy adults using diffusion-weighted magnetic resonance imaging.

Background:Diffusion-weighted magnetic resonance imaging (DWI) systems are very effective in detecting strokes, and they also have shown significant promise in the detection of fibrosis and cirrhosis of the liver. However, such systems have the disadvantages of poor reproducibility and noise, which can diminish the accuracy of the apparent diffusion coefficients (ADCs) provided by the DWI process. The main aim of this study was to determine the relationship between the age and gender of healthy adults in terms of the ADC values of the spleen measured by DWI.Methods:Sixty-nine subjects selected for this study from people who were referred to the Tabesh Medical Imaging Center in Tabriz, Iran, in 2013. Each subject underwent echo-planar DWI for her or his ADC values of the spleen with b-values of 50, 400, and 800 s/mm2, and the resulting ADC values were evaluated.Results:No significant differences were observed in ADC values of the spleen among the female and male participants or those from various ages (P>0.05).Conclusions:Based on the findings of this study, it was concluded that the effect of age and gender on the spleen’s ADC values can be omitted from the spleen-diagnosis procedure. In other words, the spleen’s ADC values are not related to the age or the gender of healthy adults.

Diffusion-weighted MR imaging in thymic epithelial tumors: correlation with World Health Organization classification and clinical staging.

To assess thymic epithelial tumors with diffusion-weighted magnetic resonance (MR) imaging. Informed consent from patients and institutional review board approval were obtained. Prospective study was conducted on 30 consecutive patients (21 men and nine women; age range, 35-71 years) with thymic epithelial tumors. They underwent true fast imaging with steady-state precession and single-shot echo-planar diffusion-weighted MR imaging of the mediastinum with b values of 0, 400, and 800 sec/mm(2). Apparent diffusion coefficient (ADC) of the thymic epithelial tumors was calculated by the same observer at two settings and was correlated with World Health Organization classification and clinical staging. There was significant difference in longest diameter (P = .001) and necrotic part of the tumor (P = .014) between low-risk thymoma, high-risk thymoma, and thymic carcinoma. Mean ADC value of both readings of thymic epithelial tumors (n = 30) was 1.24 × 10(-3) mm(2)/sec and 1.22 × 10(-3) mm(2)/sec, with good intraobserver agreement (κ = 0.732). There was significant difference in both readings (P = .01 and .20) of low-risk thymoma (1.30 × 10(-3) mm(2)/sec and 1.29 × 10(-3) mm(2)/sec), high-risk thymoma (1.16 × 10(-3) mm(2)/sec and 1.14 × 10(-3) mm(2)/sec), and thymic carcinoma (1.18 × 10(-3) mm(2)/sec and 1.06 × 10(-3) mm(2)/sec). Cutoff ADC values of both readings used to differentiate low-risk thymoma from high-risk thymoma and thymic carcinoma were 1.25 and 1.22 × 10(-3) mm(2)/sec with area under the curve of 0.804 and 0.851, respectively. There was significant difference in both readings of ADC value of early (stage I, II) and advanced stages (stage III, IV) of thymic epithelial tumors (P = .006 and .005, respectively). ADC value is a noninvasive, reliable, and reproducible imaging parameter that may help to assess and characterize thymic epithelial tumors.

Diffusion-weighted magnetic resonance imaging for assessment of lung lesions: repeatability of the apparent diffusion coefficient measurement

To establish repeatability of apparent diffusion coefficients (ADCs) acquired from free-breathing diffusion-weighted magnetic resonance imaging (DW-MRI) in malignant lung lesions and investigate effects of lesion size, location and respiratory motion. Thirty-six malignant lung lesions (eight patients) were examined twice (1- to 5-h interval) using T1-weighted, T2-weighted and axial single-shot echo-planar DW-MRI (b = 100, 500, 800 s/mm(2)) during free-breathing. Regions of interest around target lesions on computed b = 800 s/mm(2) images by two independent observers yielded ADC values from maps (pixel-by-pixel fitting using all b values and a mono-exponential decay model). Intra- and inter-observer repeatability was assessed per lesion, per patient and by lesion size (> or <2 cm) or location. ADCs were similar between observers (mean ± SD, 1.15 ± 0.28 × 10(-3) mm(2)/s, observer 1; 1.15 ± 0.29 × 10(-3) mm(2)/s, observer 2). Intra-observer coefficients of variation of the mean [median] ADC per lesion and per patient were 11% [11.4%], 5.7% [5.7%] for observer 1 and 9.2% [9.5%], 3.9% [4.7%] for observer 2 respectively; inter-observer values were 8.9% [9.3%] (per lesion) and 3.0% [3.7%] (per patient). Inter-observer coefficient of variation (CoV) was greater for lesions <2 cm (n = 20) compared with >2 cm (n = 16) (10.8% vs 6.5% ADCmean, 11.3% vs 6.7% ADCmedian) and for mid (n = 14) vs apical (n = 9) or lower zone (n = 13) lesions (13.9%, 2.7%, 3.8% respectively ADCmean; 14.2%, 2.8%, 4.7% respectively ADCmedian). Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours. • Diffusion-weighted MRI of the lung can be satisfactorily acquired during free-breathing • DW-MRI demonstrates high contrast between primary and metastatic lesions and normal lung • Apparent diffusion coefficient (ADC) measurements in lung tumours are repeatable and reliable • ADC offers potential in assessing response in lung metastases in clinical trials.

Diffusion-weighted MRI of the normal adult pancreas: The effect of age on apparent diffusion coefficient values

To investigate and characterize the effect of age on apparent diffusion coefficient (ADC) values in the normal adult pancreas using diffusion-weighted magnetic resonance imaging (DWI). Five hundred and fifty-nine adult patients without pancreatic disease, ranging from 20-81 years of age (mean 50.9 years; 436 men, 123 women), were included in this study. Breath-hold single-shot echo-planar DWI (b-values = 0, 500 s/mm(2)) was employed to determine the ADCs across all patients. Dependency of ADCs on age was characterized using a Spearman rank-order correlation test. Across the age spectrum, there was no significant correlation between ADC and age (p = 0.409). The findings of the present study suggest that the effect of age on ADCs can be excluded from the diagnosis of pancreatic diseases and design of future studies using breath-hold single-shot DWI and ADCs (as calculated with b-values of 0 and 500 s/mm(2)).

Evaluating the utility of non–echo‐planar diffusion‐weighted imaging in the preoperative evaluation of cholesteatoma: A meta‐analysis

To describe the accuracy of non-echo-planar diffusion-weighted magnetic resonance imaging (DW MRI) in identifying middle ear cholesteatoma. A meta-analysis of the published literature. A systematic review of the literature was performed to identify studies in which patients suspected of having middle ear cholesteatoma underwent DW MRI scans prior to surgery. A meta-analysis of the included studies was performed. Ten published articles (342 patients) met inclusion criteria. Cholesteatoma was confirmed in 234 patients, of which 204 were detected by DW MRI (true positives) and 30 were not (false negatives). One hundred eight patients did not have cholesteatoma on surgical examination, and of these 100 were correctly identified by MRI (true negatives) whereas eight were not (false positives). The overall sensitivity of DW MRI in detecting cholesteatoma was 0.94 (confidence interval, 0.80-0.98) and specificity 0.94 (confidence interval, 0.85-0.98). DW MRI sequences could not reliably detect cholesteatomas under 3 mm in size. Non-echo-planar DW MRI is highly sensitive and specific in identifying middle ear cholesteatoma. DW MRI may help to stratify patients into groups of who would benefit from early second-look surgery and those who could be closely observed. 2a.

Detection of recurrent and primary acquired cholesteatoma with echo-planar diffusion-weighted magnetic resonance imaging

To evaluate the diagnostic value of echo-planar diffusion-weighted magnetic resonance imaging in pre-operative detection of suspected primary acquired, residual and/or recurrent cholesteatoma. Fifty-eight chronic otitis media patients with suspected cholesteatoma were thus evaluated two weeks pre-operatively, and divided into group one (41 patients, no previous surgery, suspected primary acquired cholesteatoma) and group two (17 patients, previous surgery, scheduled 'second-look' or revision surgery for suspected residual or recurrent cholesteatoma). Patients' operative, histopathology and radiological findings were compared. Cholesteatoma was found in 63 per cent of group one patients and 58 per cent of group two patients at surgery. Histopathological examination of surgical specimens indicated that imaging accurately predicted the presence or absence of cholesteatoma in 90 per cent of group one (37/41; 23 true positives, 14 true negatives) and 76 per cent of group two (13/17; seven true positives, six true negatives). Three patients in both groups were false negative diagnoses and one patient in both groups was a false positive. The sensitivity, specificity, and positive and negative predictive values of echo-planar diffusion-weighted magnetic resonance imaging of cholesteatoma were respectively 88, 93, 95 and 82 per cent in group one and 70, 85, 87 and 66 per cent in group two. Echo-planar diffusion-weighted magnetic resonance imaging is a valuable technique with high sensitivity and specificity for cholesteatoma imaging.

Human patellar cartilage: echo planar diffusion-weighted MR imaging findings at 3.0 T

PurposeTo explore the findings of diffusion-weighted imaging (DWI) and the diffusion characteristics on patellar cartilage in healthy adults. Materials and methodsThirty healthy subjects were studied on SIEMENS 3.0-T Trio Tim magnetic resonance (MR) scanner. The apparent diffusion coefficient (ADC) values of the patellar cartilage were measured in different areas. ResultsThe patellar cartilage demonstrated homogeneously high signal intensity on the images of DWI and maps of ADC. The ADC values displayed a spatial dependency, approximately (1.17±0.31)×10−3 mm2/s of the entire cartilage. ConclusionsDiffusion-weighted MR imaging may display articular cartilage structure. There is a consistent pattern of spatial variation of the ADC values.