Use Of Diffusion-weighted Imaging Research Articles

Apparent diffusion coefficient cannot discriminate metastatic and non-metastatic lymph nodes in rectal cancer: a meta-analysis

BackgroundOur aim was to provide data regarding use of diffusion-weighted imaging (DWI) for distinguishing metastatic and non-metastatic lymph nodes (LN) in rectal cancer.MethodsMEDLINE library, EMBASE, and SCOPUS database were screened for associations between DWI and metastatic and non-metastatic LN in rectal cancer up to February 2021. Overall, 9 studies were included into the analysis. Number, mean value, and standard deviation of DWI parameters including apparent diffusion coefficient (ADC) values of metastatic and non-metastatic LN were extracted from the literature. The methodological quality of the studies was investigated according to the QUADAS-2 assessment. The meta-analysis was undertaken by using RevMan 5.3 software. DerSimonian, and Laird random-effects models with inverse-variance weights were used to account the heterogeneity between the studies. Mean DWI values including 95% confidence intervals were calculated for metastatic and non-metastatic LN.ResultsADC values were reported for 1376 LN, 623 (45.3%) metastatic LN, and 754 (54.7%) non-metastatic LN. The calculated mean ADC value (× 10−3 mm2/s) of metastatic LN was 1.05, 95%CI (0.94, 1.15). The calculated mean ADC value of the non-metastatic LN was 1.17, 95%CI (1.01, 1.33). The calculated sensitivity and specificity were 0.81, 95%CI (0.74, 0.89) and 0.67, 95%CI (0.54, 0.79).ConclusionNo reliable ADC threshold can be recommended for distinguishing of metastatic and non-metastatic LN in rectal cancer.

Breast Lesion Characterisation with Diffusion Weighted Imaging Versus Dynamic Contrast Enhanced-MRI: A Prospective Observational Study in a Tertiary Care Hospital

Purpose: Dynamic contrast-enhanced (DCE)-MRI has a promising role in breast cancer detection and lesion characterisation. Diffusion-weighted imaging (DWI) acts as an adjunct in the differentiation between benign and malignant lesions. The purpose of the study was to evaluate the efficacy of DCE-MRI and DWI in differentiating benign and malignant lesions. Methods: In a prospective study conducted between March 2019 and February 2020, 60 patients with breast lesions underwent DWI combined with DCE-MRI of the breast. The time–intensity curves were plotted. Lesions were classified according to the latest American College of Radiology Breast Imaging Reporting and Data System (ACR BI-RADS; 5th edition). The results were compared with the histopathological diagnosis. The sensitivity and specificity of DWI, DCE-MRI, and combined DWI and DCE-MRI were calculated for detection of benign and malignant breast lesions. Results: Sixty patients underwent breast MRI in which 78 lesions were detected, out of which 28 were benign and 50 were malignant. Quantitative apparent diffusion coefficient measurement revealed 96% sensitivity and 82% specificity, with a positive predictive value of 92% and negative predictive value of 96%, for differentiating benign from malignant lesions. DCE-MRI findings showed 96% sensitivity and 78.5% specificity. The sensitivity of combined DWI and DCE-MRI was 98% and specificity was 86%, which was higher than DWI and DCE-MRI alone. Conclusion: Multiparametric MRI of the breast has very high sensitivity for detecting and characterising breast lesions as benign or malignant lesions. DWI had higher specificity than DCE-MRI, and the combined use of DWI and DCE-MRI had greater efficacy than DWI and DCE-MRI alone.

The utility of diffusion-weighted imaging and ADC values in the characterization of mumps orchitis and seminoma.

Diffusion-weighted imaging (DWI) can quantitatively reflect the diffusion characteristics of tissues, providing a theoretical basis for qualitative diagnosis and quantitative analysis of a disease. To characterize testicular lesions that present as a hypointense signal on magnetic resonance imaging (MRI) T2-weighted images using DWI. Study participants were divided into three groups. Group A were healthy controls (n = 35), group B included patients with mumps orchitis (n = 20), and group C included patients with seminoma (n = 15). DWI sequences used b-values of 0, 1000, and 2000 s/mm2. Apparent diffusion coefficient (ADC) values between 1000 and 2000 s/mm2 were calculated by MRI postprocessing software. The Kruskal-Wallis test and receiver operating characteristic analysis were performed to evaluate how well ADC values distinguished between mumps orchitis and seminoma. Normal testicular tissue showed a hyperintense signal on DWI and hypointensity on the ADC map: mean ADC value was 0.77 (0.69-0.85) ± 0.08 ×10-3 mm2/s. Mumps orchitis and seminoma showed slight hyperintensity on DWI: mean ADC values were 0.85 (0.71-0.99) ± 0.15 ×10-3 mm2/s and 0.43 (0.39-0.47) ± 0.04 × 10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testicular tissue and seminoma and between mumps orchitis and seminoma. The cutoff ADC value for differentiating seminoma from mumps orchitis was 0.54 × 10-3 mm2/s. The sensitivity, specificity, and Youden Index for diagnosing seminoma were 99%, 31%, and 30%, respectively. High b-value DWI has potential utility for differentiating mumps orchitis from seminoma in the clinical setting.

The role of diffusion-weighted MRI in assessment of response to chemotherapy in osteosarcoma

BackgroundThe most effective treatment for osteosarcoma is neoadjuvant chemotherapy along with surgical resection of the tumor. The prognosis significantly correlates with the degree of tumor necrosis following preoperative chemotherapy. The tumor necrosis will result in loss of the cell membrane integrity and expansion of the extracellular diffusion space which can be detected as an increase in the mean ADC value. The aim of our work is to evaluate the use of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) value measurement for monitoring the therapeutic response after chemotherapy in osteosarcoma.ResultsThis study included 25 cases of osteosarcoma: 15 males and 10 females. The age of the patients ranged from 7 to 46 years with mean age 22 years. All were assessed by magnetic resonance imaging (MRI) including DWI and the mean and minimum ADC values were calculated before and after chemotherapy. Follow-up DWI post-therapy revealed a rise in mean ADC value in 17 patients who considered having good response. The ADC value had been raised from 1.05 ± 0.4 × 10−3 mm2/s to 1.82 ± 0.45 × 10−3 mm2/s (P < 0.027) that is statistically moderately significant. In 8 patients, the post-therapy ADC value was similar to that of pre- or with a little change and they were considered having poor response. It showed changes from 1.29 ± 0.35 × 10−3 mm2/s to 1.32 ± 0.36 × 10−3 mm2/s (P > 0.05) that means no significant difference.ConclusionDWI and ADC value measurement play an important role in monitoring the therapeutic response after chemotherapy in osteosarcoma patients by comparing the mean ADC values before and after treatment.

The use of diffusion-weighted imaging at 3 Tesla magnetic resonance imaging in differentiating malignant from benign portal vein thrombosis

Giriş ve Amaç: Bu çalışmada malign ile benign portal ven trombozunun ayrımında 3 Tesla manyetik rezonans görüntülemede difüzyon ağırlıklı görüntülemenin rolünün araştırılması amaçlanmaktadır. Gereç ve Yöntem: Ocak 2011 - Aralık 2016 tarihleri arasında 3 Tesla manyetik rezonans görüntüleme ünitesinde elde edilmiş abdomen manyetik rezonans görüntüleme incelemeleri portal ven trombozu mevcut olguları tespit etmek için retrospektif olarak değerlendirildi. Kontrastsız görüntüler ile karşılaştırıldığında arteriyel faz kontrastlı görüntülerde ≥%15 kontrast tutulumu gösteren portal ven trombozu malign olarak kabul edildi. Tromboz saptanan portal venin çapı ölçülüp difüzyon ağırlıklı görüntülerde portal ven trombozu sinyal intensitesi kaydedildi. İki bağımsız gözlemci tarafından malign ve benign portal ven trombozlarının görünür difüzyon katsayısı değerleri ölçüldü. Bulgular: Malign portal ven trombozu bulgusu olan 23 olgu [19 erkek, 4 kadın; ortanca yaş 63 (52-83)] ve benign portal ven trombozu bulgusu olan 14 olgu [5 erkek, 9 kadın; ortanca yaş 65 (47-82)] tespit edildi. Difüzyon ağırlıklı görüntülerde malign ile benign portal ven trombozu sinyal intensitesi yönünden istatistiksel olarak anlamlı fark saptandı (p

Diffusion-weighted magnetic resonance imaging (DWMRI) of head and neck squamous cell carcinoma: could it be an imaging biomarker for prediction of response to chemoradiation therapy

BackgroundChemoradiation therapy (CRT) has become a primary definitive treatment modality for head and neck squamous cell carcinoma (HNSCC); however, not all patients respond completely to treatment. Ability to identify those patients, who would not achieve complete response, before or early during the course of CRT will allow treatment modifications to improve outcome and overall survival. The aim of this prospective study was to assess the usefulness of diffusion-weighted imaging (DWI) in prediction of early therapeutic response of HNSCC after CRT.ResultsLocal control was achieved in 22 patients out of 46 patients with pathologically proven HNSCC treated by chemoradiation therapy and local failure was detected in 24 patients out of 46 patients. Pretreatment mean apparent diffusion coefficient (ADCpre) was significantly higher in local failure group (1.1 ± 0.2 × 10−3 mm2/s) than local control group (0.89 ± 0.1 × 10−3 mm2/s). An optimal cut-off value of more than 0.94 × 10−3 mm2/s was predictive of local failure with sensitivity 83.33%, specificity 59.9%, PPV 69%, NPV 76.5%. Early intra-treatment percentage change of ADC (ΔADC) was significantly lower in local failure group (21.8% ± 21.3) than in local control group (45.2% ± 27.8). An optimal cut-off value of ≤ 33% was predictive of local failure after CRT with sensitivity of 71.34%, specificity of 60%, PPV of 62.5%, and NPV of 69.2%.ConclusionsDiffusion-weighted MRI could be a potential predictive biomarker for therapeutic response of HNSCC to CRT. Primary tumors with higher pretreatment mean ADC, and a smaller early intratreatment percentage increase of mean ADC would be more likely to fail treatment.

Quantitative characterization of extraocular orbital lesions in children using diffusion-weighted imaging.

Diffusion-weighted imaging (DWI) has been shown to be helpful in providing information about cellular density and also predicting the histological features of aggressive tumors. Several studies have evaluated this technique for orbital tumors. However, very few articles have focused exclusively on evaluating pediatric orbital masses and, within those, only a small number of patients were included in the study. This study aimed to evaluate the use of DWI and apparent diffusion coefficient (ADC) values to differentiate between benign and malignant extraocular orbital lesions in children. This retrospective study included 73 patients under the age of 18 seen in our hospital between October 2016 and February 2019. The extraocular orbital lesions were evaluated clinically and radiologically using DWI. The diagnosis was confirmed by either histological examination (after biopsy or surgery) or based on clinical and radiologic evaluation. The malignant lesions were found to have increased diffusion restriction in comparison to the benign lesions. The ADC values of the malignant lesions were significantly lower (P<0.0001). The use of a cutoff value of 0.99×10-3mm2/s allowed for the differentiation of the benign lesions and malignant lesions with a sensitivity of 75% and a specificity of 100% while the cutoff point of 1.26×10-3mm2/s had a sensitivity of 100% and a specificity of 73%. Measurement of ADC in extraocular orbital lesions in children may help differentiate malignant lesions from benign lesions.

Pictorial review of whole body MRI in myeloma: emphasis on diffusion-weighted imaging.

There have been major advances in myeloma imaging over the past few years with focal lesions on imaging now forming part of the disease defining criteria. Whole body diffusion-weighted MRI (WB-MRI) is considered the most sensitive technique for the detection of focal active lesions. This pictorial review will focus on imaging the spectrum of myelomatous disorders on WB-MRI including diffusion and Dixon sequences. The typical imaging patterns of disease are demonstrated including in the contexts of staging, presumed solitary plasmacytoma, smouldering myeloma and examples of paramedullary and extramedullary disease. The utility of diffusion-weighted imaging in response assessment is a major advantage and this will be exemplified here.

Use of diffusion-weighted imaging in the noninvasive diagnostic of obstructed biliary ducts.

This study sought to evaluate the role of diffusion-weighted imaging (DWI) in differentiation between obstructed and unobstructed bile ducts in patients undergoing magnetic resonance imaging (MRI). Eighty-four patients, 40 males and 44 females (mean age: 56.4 ± 15.1years), undergoing MRI with DWI (0-50-500-700) were evaluated and divided into two groups: 58 with abnormal laboratory tests (obstructed group) and 26 with normal laboratory values (unobstructed group). Laboratory tests were total bilirubin, alkaline phosphatase, and gamma-glutamyltransferase. Median ADC values were calculated and correlated with laboratory tests and degree of bile-duct dilatation (absent, moderate, or severe). The persistence of signal on DWI (b500 and b700) in the biliary tract was evaluated. Bilirubin values were tested for correlation with bile-duct ADC values and persistence of b700 signal. For statistical analysis, Student t test, chi-square test and Wilcoxon-Mann-Whitney test were used. ADC maps were plotted for three levels of the biliary tree, and a receiver operating characteristic (ROC) curve was calculated. In the obstructed group, 15 patients had severe dilatation, 24 had moderate dilatation, and 19 had no appreciable dilatation; 38 patients had persistent signal on b700 images. In the unobstructed group, 23 patients had no dilatation and 3 had moderate dilatation; 4 patients had persistent signal on b700 images. Correlation was found between degree of bile-duct dilatation, bilirubin levels, persistence of b700 signal, and ADC map values. The calculated ADC map cutoff value (353 10-6 mm2/s) was able to differentiate the obstructed and unobstructed groups with 92.3% sensitivity, 81% specificity, and 91.9% accuracy. DWI is able to distinguish patients with obstructed versus unobstructed bile ducts, regardless of the degree of dilatation, correlating with clinical and laboratory findings.

Biomarkers of pituitary macroadenomas aggressive behaviour: a conventional MRI and DWI 3T study.

Pituitary macroadenomas (PAs) are usually defined as benign intracranial tumors. However, they may present local aggressive course. High Ki67 labelling index (LI) values have been related to an aggressive tumor behavior. A recent clinicopathological classification of PA based on local invasiveness and proliferation indexes, divided them in groups with different prognosis. We evaluated the utility of conventional MRI (cMRI) and diffusion-weighted imaging (DWI), in predicting the Ki67- LI according the clinicopathological classification. 17 patients (12 M and 5 F) who underwent surgical removal of a PA were studied. cMRI features, quantification of T1W and T2W signal intensity, degree of contrast uptake (enhancement ratio, ER) and apparent diffusion coefficient (ADC) values were evaluated by using a 3 T scan. Statistics included Mann-Whitney test, Spearman's test, and receiver operating characteristic analysis. A value of p ≤ 0.05 was considered significant for all the tests. Negative correlations were observed between Ki-67 LI, ADCm (ρ = - 0.67, p value = 0.005) and ER values (ρ = -0.62; p = 0.008). ER values were significantly lower in the proliferative PA group (p = 0.028; p = 0.017). ADCm showed sensitivity and specificity of 90 and 85% respectively into predict Ki67-LI value. A value of ADCm ≤0, 711 x 10-6 mm2 emerged as a cut-off of a value of Ki67-LI ≥ 3%. Adding quantitative measures of ADC values to cMRI could be used routinely as a non-invasive marker of specific predictive biomarker of the proliferative activity of PA. Routinely use of DWI on diagnostic work-up of pituitary adenomas may help in establish the likely biological aggressive lesions.

Use of diffusion-weighted imaging to distinguish seizure-related change from limbic encephalitis.

To determine whether diffusion-weighted imaging (DWI) can help differentiate peri-ictal signal abnormality from limbic encephalitis (LE) among patients with medial temporal lobe T2-hyperintensity. We retrospectively identified patients with peri-ictal medial temporal lobe T2-hyperintensity using a Mayo Clinic database, and reviewed their DWI to look for unique diffusion restriction patterns. We then identified patients with medial temporal lobe T2-hyperintensity and LE, and reviewed their DWI to see if these patterns were ever present. Presence of diffusion restriction patterns was confirmed by a blinded neuro-radiologist. We identified 10 patients without LE who had peri-ictal unilateral medial temporal lobe T2-hyperintensity, ipsilateral to focal seizure onset. Nine of 10 (90%) had at least one of two diffusion restriction patterns potentially unique to seizure activity; four had gyriform hippocampal diffusion restriction ("Pattern 1"), three had diffuse hippocampal diffusion restriction that spared the most medial temporal lobe structures ("Pattern 2"), and two had both diffusion restriction patterns. The median patient age was 62years (range 2-76years) and 3/9 (33%) were female. In comparison, among patients with medial temporal lobe T2-hyperintensity and LE, only 5/57 (9%) had one of the diffusion restriction patterns ("Pattern 2") identified (P < 0.0001); all five had seizures reported. In patients with medial temporal lobe T2-hyperintensity and one of the diffusion restriction patterns described herein, the signal abnormality may be a peri-ictal phenomenon rather than indicative of LE and should prompt investigation for seizure. Even in patients with LE, these patterns should raise concern for seizure.

Gross tumour volume delineation in anal cancer on T2-weighted and diffusion-weighted MRI – Reproducibility between radiologists and radiation oncologists and impact of reader experience level and DWI image quality

PurposeTo assess how gross tumour volume (GTV) delineation in anal cancer is affected by interobserver variations between radiologists and radiation oncologists, expertise level, and use of T2-weighted MRI (T2W-MRI) vs. diffusion-weighted imaging (DWI), and to explore effects of DWI quality. Methods and materialsWe retrospectively analyzed the MRIs (T2W-MRI and b800-DWI) of 25 anal cancer patients. Four readers (Senior and Junior Radiologist; Senior and Junior Radiation Oncologist) independently delineated GTVs, first on T2W-MRI only and then on DWI (with reference to T2W-MRI). Maximum Tumour Diameter (MTD) was calculated from each GTV. Mean GTVs/MTDs were compared between readers and between T2W-MRI vs. DWI. Interobserver agreement was calculated as Intraclass Correlation Coefficient (ICC), Dice Similarity Coefficient (DSC) and Hausdorff Distance (HD). DWI image quality was assessed using a 5-point artefact scale. ResultsInterobserver agreement between radiologists vs. radiation oncologists and between junior vs. senior readers was good–excellent, with similar agreement for T2W-MRI and DWI (e.g. ICCs 0.72–0.94 for T2W-MRI and 0.68–0.89 for DWI). There was a trend towards smaller GTVs on DWI, but only for the radiologists (P = 0.03–0.07). Moderate-severe DWI-artefacts were observed in 11/25 (44%) cases. Agreement tended to be lower in these cases. ConclusionOverall interobserver agreement for anal cancer GTV delineation on MRI is good for both radiologists and radiation oncologists, regardless of experience level. Use of DWI did not improve agreement. DWI artefacts affecting GTV delineation occurred in almost half of the patients, which may severely limit the use of DWI for radiotherapy planning if no steps are undertaken to avoid them.

Which MRI Score and Technique Should Be Used for Assessing Crohn's Disease Activity?

Magnetic resonance (MR) enterography is assuming an increasingly important and central role in the management of patients with Crohn’s disease, as it is not only involved in diagnosis and staging of the disease but also allows for patients’ follow-up, evaluating the response to therapy, and predicting disease outcomes. Several MR scores have been developed but unfortunately there is no globally accepted score. The most widely used scores are the Magnetic Resonance Index of Activity (MaRIA) score, the London score, the Nancy score, and the Clermont score; however, there are multiple differences between these tools in terms of the assessed radiological items, fasting, administration of oral or intravenous contrast, and the use of diffusion-weighted images. Here we reviewed the main characteristics of each MR scoring system to clarify which is the most appropriate score for monitoring disease activity in both clinical practice and clinical trials.

Diffusion-weighted Imaging Reversibility In Stroke After Successful Mechanical Recanalization. Case report

Increased use of Diffusion-weighted imaging (DWI) in acute stroke has led to observations of early diffusion normalization in lesions thatinitially show diffusion slowing. The “renormalization” of DWI may be spontaneous or the result of thrombolytic therapy, thus, acuteslowing of diffusion is not necessarily an indicator of irreversible tissue damage. The perfusion-diffusion mismatch concept is attractiveas it assumes that DWI lesion size reflects the infarct core whilst the mismatch area reflects the penumbra. However, this concept maybe an oversimplification. This paper shows a case with Diffusion Lesion Reversal after successful neuroendovascular treatment andexcellent clinical outcome, and discuss the imaging characteristics associated with this phenomenon.

Imaging of Hypoxic Tumor: Correlation between Diffusion-weighted MR Imaging and 18F-fluoroazomycin Arabinoside Positron Emission Tomography in Head and Neck Carcinoma.

We investigated the usefulness of diffusion-weighted imaging (DWI) for detecting changes in the structure of hypoxic cells by evaluating the correlation between 18F-fluoroazomycin arabinoside (FAZA) positron emission tomography activity and DWI parameters in head and neck carcinoma. The diffusion coefficient corresponding to the slow compartment of a two-compartment model had a significant positive correlation with FAZA activity (ρ = 0.58, P = 0.016), whereas the diffusional kurtosis from diffusion kurtosis imaging had a significant negative correlation (ρ = −0.62, P = 0.008), which suggests that those DWI parameters might be useful as indicators for changes in cell structure.

The Utility of Diffusion-Weighted Imaging and Perfusion Magnetic Resonance Imaging Parameters for Detecting Clinically Significant Prostate Cancer

IntroductionTo establish the diagnostic performance of the parameters obtained from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging at 3T in discriminating between non-clinically significant prostate cancers (ncsPCa, Gleason score [GS] < 7) and clinically significant prostate cancers (csPCa, GS ≥ 7) in the peripheral zone. Materials and MethodsTwenty-six male patients with peripheral zone prostate cancer (PCa) who had undergone 3T multiparametric magnetic resonance imaging (MRI) scan prior to biopsy were included in the study and evaluated retrospectively. The GS was obtained by both standard 12-core transrectal ultrasound guided biopsy and targeted MRI-US fusion biopsy and then confirmed by prostatectomy, if available. For each confirmed tumour focus, DCE-derived quantitative perfusion metrics (Ktrans, Kep, Ve, initial area under the curve [AUC]), the apparent diffusion coefficient (ADC) value, and normalized versions of quantitative metrics were measured and correlated with the GS. ResultsKtrans had the highest diagnostic accuracy value of 82% among the DCE-MRI parameters (AUC 0.90), and ADC had the strongest diagnostic accuracy value of 87% among the overall parameters (AUC 0.92). The combination of ADC and Ktrans have higher diagnostic performance with the area under the receiver operating characteristic curve being 0.98 (sensitivity 0.94; specificity 0.89; accuracy 0.92) compared to the individual evaluation of each parameter alone.The GS showed strong negative correlations with ADC (r = −0.72) and normalized ADC (r = −0.69) as well as a significant positive correlation with Ktrans (r = 0.69). ConclusionThe combination of Ktrans and ADC and their normalized versions may help differentiate between ncsPCa from csPCa in the peripheral zone.

Computed tomography and/or magnetic resonance imaging of the liver : How, why, what for?

Colorectal metastases are the most common malignant liver lesions. Imaging of the liver in patients with colorectal carcinoma is performed for early detection of liver metastases (CRLM) at the time of initial tumor diagnosis, for monitoring and follow-up in order to exclude or diagnose metachronous metastases. Radiological imaging includes primarily multislice computed tomography (CT) and magnetic resonance imaging (MRI), which play an important role regarding therapeutic management and assessment of prognosis. Contrast-enhanced CT is broadly available and allows for rapid image acquisition including the possibility for complete tumor staging. MRI, on the other hand, is characterized by very good soft tissue contrast and has-especially with the use of diffusion-weighted imaging and administration of liver-specific contrast agents-the highest sensitivity for detection of metastases smaller than 1 cm. The choice of imaging in daily routine is often dependent on availability and clinical question. Frequently, e.g. for assessment of resectability (extent of metastases, anatomic relation of lesions to critical structures), both modalities may be implemented in combination.

Primary and post-chemoradiotherapy staging using MRI in rectal cancer: the role of diffusion imaging in the assessment of perirectal infiltration.

To analyze changes in MRI diagnostic accuracy in main rectal tumor (T) evaluation resulting from the use of diffusion-weighted imaging (DWI), according to the degree of experience of the radiologist. This is a cross-sectional study of a database including one hundred 1.5 T MRI records (2011-2016) from patients with biopsy-proven rectal cancer, including primary staging and post-chemoradiotherapy follow-up. All cases were individually blindedly reviewed by ten radiologists: three experienced in rectal cancer, three specialized in other areas, and four residents. Each case was assessed twice to detect perirectal infiltration: first, evaluating just high-resolution T2-weighted sequences (HRT2w); second, evaluation of DWI plus HRT2w sequences. Results were pooled by experience, calculating accuracy (area under ROC curve), sensitivity and specificity, predictive values, likelihood ratios, and overstaging/understaging. Histology of surgical specimens provided the reference standard. DWI significantly improved specificity by experienced radiologists in primary staging (63.2% to 75.9%) and, to a lesser extent, positive likelihood ratio (2.06 to 2.87); minimal changes were observed post-chemoradiotherapy, with a slight decrease of accuracy (0.657 to 0.626). Inexperienced radiologists showed a similar pattern, but with slight enhancement post-chemoradiotherapy (accuracy 0.604 to 0.621). Residents experienced small changes, with increased sensitivity/decreased specificity in both primary (69% to 72%/67.2% to 64.7%) and post-chemoradiotherapy (68.1% to 73.6%/47.3% to 44.6%) staging. Adding DWI to HRT2w significantly improved specificity for the detection of perirectal infiltration at primary staging by experienced radiologists and also by inexperienced ones, although to a lesser extent. In the post-neoadjuvant treatment subgroup, only minimal changes were observed.

The usefulness of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences visual assessment in the early diagnosis of axial spondyloarthritis

The aim of the study was to compare the diagnostic efficacy of the visual assessment of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences compared to the STIR sequence in the diagnostics of active sacroiliitis in the course of axial spondyloarthritis (axSpA). The study group consisted of 49 patients who had undergone multiparametric magnetic resonance imaging of the sacroiliac joints (SIJs) due to clinical suspicion of axSpA. Two independent observers retrospectively assessed four quadrants of the SIJs for the presence of subchondral bone marrow oedema/osteitis with the use of modified SPARCC score in sequences: STIR, DWI (with ADC map) and DCE. Diagnostic efficiency parameters were calculated for DWI and DCE sequence separately, using STIR sequence as a reference. Inter-observer agreement was evaluated with the use of κ coefficient. Patients’ clinical symptoms were analysed to identify the group fulfilling the imaging arm of the ASAS criteria for axSpA. Overall, 46.9% (n = 23) of patients fulfilled the imaging arm of ASAS criteria for axial spondyloarthritis. DWI with ADC map: accuracy 95.6%, sensitivity 99.4%, specificity 54.0%. DCE sequence: accuracy 96.8%, sensitivity 98.4%, specificity 79.5%. The highest level of inter-observer agreement was achieved for STIR sequence (κ = 0.888), slightly lower for DCE sequence (κ = 0.773) and the lowest for DWI with ADC (κ = 0.674). Visual assessment of the DWI and DCE sequences has high accuracy and sensitivity of bone marrow oedema/osteitis detection, but the specificity and inter-observer agreement are poor, especially for the DWI sequence with ADC maps.

Differentiation of benign and malignant cervical lymph nodes on MRI with special emphasis on DWI

Aim and objectives: Evaluation of cervical lymph nodes with MRI, utility of DWI in differentiation of benign and malignant cervical lymph nodes.Methods: Prospective study was carried out on 71 patients of cervical lymphadenopathy in Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune over a period of two years. Patients were evaluated with Siemens MAGNETOM Avanto 1.5 T MRI machine. Characteristics of cervical lymph nodes on T1WI, T2WI, STIR and Diffusion weighted images with ADC values were studied. Comparison was made with histopathological reports to study accuracy of MRI DWI in differentiating benign and malignant lymph nodes. Results: Out of the total 71 cases, 41 cases were of benign lymph nodes and 30 cases were of malignant lymph nodes. Characteristics of lymph nodes were studied on MRI. Malignant lymph nodes showed diffusion restriction with corresponding low ADC values. Mean ADC value of benign lymph nodes was 1.1×10-3mm2/s (±0.9 SD) and for malignant lymph nodes was 0.7×10-3mm2/s (±0.2 SD).The suggested ADC cut off value in our study for differentiating benign from malignant lymph nodes was to be 0.93×10-3 mm2/s. Conclusion: Diffusion weighted imaging (DWI) is an important non-invasive diagnostic method for differentiation of benign and malignant cervical lymph nodes in case of head, neck cancers.