Apparent diffusion coefficient modifications in assessing gastro-oesophageal cancer response to neoadjuvant treatment: comparison with tumour regression grade at histology

Objectives

To assess changes in apparent diffusion coefficient (ΔADC) and volume (ΔV) after neoadjuvant treatment (NT), and tumour regression grade (TRG) in gastro-oesophageal cancers (GEC), and to discriminate responders from non-responders.

Methods

Thirty-two patients with biopsy-proven locally-advanced GEC underwent diffusion weighted magnetic resonance imaging (DWI) pre- and post-NT. Lesion ADC, volume, ΔADC and ΔV were calculated. TRG 1-2-3 patients were classified as R; TRG 4-5 as non-responders. ΔADC-TRG and ΔV-TRG correlations, pre-NT and post-NT ADC, ΔADC and ΔV cut-off values for responders and non-responders were calculated. Two readers measured mean tumour ADCs and interobserver variability was calculated. (Spearman’s and intraclass correlation coefficient [ICC]).

Results

The interobserver reproducibility was very good both for pre-NT (Spearman’s rho?=?0.8160; ICC?=?0.8993) and post-NT (Spearman’s rho?=?0.8357; ICC?=?0.8663). Responders showed lower pre-NT ADC (1.32 versus 1.63?×?10^?3?mm²/s; P?=?0.002) and higher post-NT ADC (2.22 versus 1.51?×?10^?3?mm²/s; P?=?0.001) than non-responders and ADC increased in responders (ΔADC, 85.45 versus ?8.21 %; P?=?0.00005). ΔADC inversely correlated with TRG (r?=??0.71, P?=?0.000004); no difference in ΔV between responders and non-responders (?50.92 % versus ?14.12 %; P?=?0.068) and no correlation ΔV-TRG (r?=?0.02 P?=?0.883) were observed.

Conclusions

The ADC can be used to assess gastro-oesophageal tumour response to neoadjuvant treatment as a reliable expression of tumour regression.

Key Points

? DWI is now being used to assess many cancers. ? Change in ADC measurements offer new information about oesophageal tumours. ? ADC changes are more reliable than dimensional criteria in assessing neoadjuvant treatment. ? Such ADC assessment could optimise management of locally advanced gastro-oesophageal cancers.     

Proton MR Spectroscopy of the brain in children with neuronopathic Gaucher’s disease

Objective

To assess the clinical usefulness of proton magnetic resonance spectroscopy (¹H-MRS) in children with neuronopathic Gaucher’s disease (NGD).

Methods

A prospective study was conducted upon 21 consecutive children with acute (n?=?7) and chronic (n?=?14) forms of NGD (13 boys, 8 girls; mean age 37 months) and for a control group (n?=?15). All patients and controls underwent ¹H-MRS of frontal white matter. The choline/creatine (Ch/Cr) and N-acetyl aspartate (NAA)/Cr ratios were calculated. A modified severity scoring tool (m-SST) of NGD was calculated and genotyping was performed for all patients. Metabolic ratios were correlated with clinical types, m-SST and genotyping.

Results

There was a significant difference in Ch/Cr (P?=?0.001) between patients with NGD and the control group. Lipid peak was detected in 15 patients with NGD. Patients with acute NGD revealed higher m-SST (P?=?0.001) and Ch/Cr (P?=?0.001) compared with the chronic form. Patients with homozygous gene mutation (L444P/L444P) had significantly higher m-SST (P?=?0.001) and Ch/Cr (P?=?0.013) than those with the heterozygous gene mutation (L444P/other). The Ch/Cr was negatively correlated with m-SST (r?=??0.682; P?=?0.001)

Conclusion

¹H-MRS can be used to detect brain abnormalities in children with NGD and Ch/Cr is well correlated with m-SST and genotyping.

Key Points

? Proton magnetic resonance spectroscopy offers important information in some paediatric neurological conditions. ? Significantly different choline/creatine ratios were found between neuronopathic Gaucher’s disease and controls. ? Lipid peak helps with the diagnosis of neuronopathic Gaucher’s disease. ? Ch/Cr correlated with the modified severity scoring tool of Gaucher’s disease.     

Minimal hepatic encephalopathy in children with liver cirrhosis: diffusion-weighted MR imaging and proton MR spectroscopy of the brain

Introduction

The aim of this work was to detect minimal hepatic encephalopathy (minHE) in children with diffusion-weighted MR imaging (DWI) and proton magnetic resonance spectroscopy (¹H-MRS) of the brain.

Methods

Prospective study conducted upon 30 consecutive children (age range 6–16 years, 21 boys and 9 girls) with liver cirrhosis and 15 age- and sex-matched healthy control children. Patients with minHE (n?=?17) and with no minHE (n?=?13) groups and control group underwent DWI, ¹H-MRS, and neuropsychological tests (NPTs). The glutamate or glutamine (Glx), myoinositol (mI), choline (Cho), and creatine (Cr) at the right ganglionic region were determined at ¹H-MRS. The apparent diffusion coefficient (ADC) value and metabolic ratios of Glx/Cr, mI/Cr, and Cho/Cr were calculated.

Results

There was elevated ADC value and Glx/Cr and decreased mI/CI and Ch/Cr in patients with minHE compared to no minHE and control group. There was significant difference between minHE, no minHE, and control group in the ADC value (P?=?0.001 for all groups), GLx/Cr (P?=?0.001 for all groups), mI/Cr (P?=?0.004, 0.001, and 0.001, respectively), Ch/Cr (P?=?0.001 for all groups), and full-scale IQ of NPT (P?=?0.001, 0.001, and 0.143, respectively). The NPT of minHE had negative correlation with ADC value (r?=??0.872, P?=?0.001) and GLx/Cr (r?=??0.812, P?=?0.001) and positive correlation with mI/Cr (r?=?0.732, P?=?0.001).

Conclusion

DWI and ¹H-MRS are imaging modalities that can detect minHE in children with liver cirrhosis and correlate well with parameters of NPT.     

Diffusion-weighted magnetic resonance imaging using different b-value combinations for the evaluation of treatment results after volumetric MR-guided high-intensity focused ultrasound ablation of uterine fibroids

Objectives

To assess the value of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) mapping using different b-value combinations for treatment evaluation after magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) of uterine fibroids.

Methods

Fifty-six patients with 67 uterine fibroids were treated with volumetric MR-HIFU. Pre-treatment and post-treatment images were obtained using contrast-enhanced T1-weighted MRI (CE-T1WI) and DWI using b?=?0, 200, 400, 600, 800 s/mm². ADC maps were generated using subsets of b-values to investigate the effects of tissue ablation on water diffusion and perfusion in fibroids treated with MR-HIFU. Four combinations of b-values were used: (1) all b-values; (2) b?=?0, 200 s/mm²; (3) b?=?400, 600, 800 s/mm²; and (4) b?=?0, 800 s/mm².

Results

Using the lowest b-values (0 and 200 s/mm²), the mean ADC value in the ablated tissue reduced significantly (p?b-values (400, 600, 800 s/mm²), the ADC increased significantly (p?b-values resulted in the best visual agreement of non-perfused fibroid tissue detected on CE images. Other b-value combinations and normal myometrium showed no difference in ADC after MR-HIFU treatment.

Conclusions

A decrease in contrast agent uptake within the ablated region on CE-T1WI was correlated to a significantly decreased ADC when b?=?0 and 200 s/mm² were used.

Key Points

? DWI could be useful for treatment evaluation after MR-HIFU of uterine fibroids ? The ADC in fibroid tissue is influenced by the choice of b- values ? Low b-values seem the best choice to emphasise perfusion effects after MR-HIFU     

Assessing response in bone metastases in prostate cancer with diffusion weighted MRI

Objectives

To determine whether changes in ADC of bone metastases secondary to prostate carcinoma are significantly different in responders compared with progressors on chemotherapy.

Methods

Twenty-six patients with known bone metastases secondary to prostate carcinoma underwent diffusion-weighted MRI of the lumbar spine and pelvis at baseline and 12 weeks following chemotherapy. RECIST assessment of staging CT and PSA taken at the same time points were used to classify patients as responders, progressors or stable. ADC (from b?=?0,50,100,250,500,750 smm^?2) and ADC_slow (from b?=?100,250,500,750 smm^?2) were calculated for up to 5 lesions per patient.

Results

Mean ADC/ADC_slow in lesions from responders and progressors showed a significant increase. Although the majority of lesions demonstrated an ADC/ADC_slow rise, some lesions in both responders and progressors demonstrated a fall in ADC beyond the limits of reproducibility.

Conclusions

Mean ADC is not an appropriate measure of response in bone metastases. The heterogeneity of changes in ADC is likely to be related to the composition of bone marrow with changes that have opposing effects on ADC.     

Roles of the apparent diffusion coefficient and tumor volume in predicting tumor grade in patients with choroid plexus tumors

Purpose

To explore the utility of the apparent diffusion coefficient (ADC) and tumor volume to predict histological grade and prognosis in patients with choroid plexus tumors.

Methods

ADC and tumor volumes were retrospectively evaluated in 25 patients with choroid plexus papilloma (CPP; WHO grade 1 [n?=?13]), atypical CPP (aCPP; grade 2 [n?=?8]), or choroid plexus carcinoma (grade 3 [n?=?4]) The prognostic roles of ADC and tumor volume were assessed.

Results

There were significant differences in mean and minimum ADC values, and tumor volume among the WHO grades (p?=?0.033, p?=?0.044, and p?=?0.014, respectively). Receiver-operating characteristic analysis revealed a mean cutoff ADC value ≤?1.397?×?10^?3 mm²/s for aCPP (sensitivity?=?0.667, specificity?=?0.923). Multiple linear regression analysis demonstrated that both mean ADC (β?=???0.455, p?=?0.005) and tumor volume (β?=?0.513, p?=?0.002) were correlated with WHO grade (adjusted R²?=?0.520, p?=?0.005). Kaplan-Meier curve analysis identified poorer survival in patients with WHO grade 2 and 3 tumors than in those with WHO grade 1 disease (p?=?0.049 and p?=?0.012, respectively). A mean ADC?≤?1.397?×?10^?3 mm²/s (p?=?0.001) and tumor volume 21.05 ml (p?=?0.031) predicted significantly poorer survival.

Conclusion

Mean ADC and tumor volume were correlated with WHO grade of choroid plexus tumors. A lower ADC value and a larger tumor volume predicted a poorer prognosis.

     

Apparent diffusion coefficient as a prognostic biomarker of upper urinary tract cancer: a preliminary report

Objectives

To investigate the role of apparent diffusion coefficient (ADC) as a biomarker reflecting the aggressiveness of upper urinary tract urothelial cell carcinoma (UUT-UCC).

Methods

Thirty-four consecutive patients treated with nephroureterectomy for non-metastatic disease were prospectively enrolled in this study. ADC was compared with clinicopathological variables including Ki-67 labelling index (LI) and cancer-specific survival (CSS).

Results

The overall 3-year CSS rate was 82 % (median follow-up, 36 months). ADC was significantly lower in grade 3 disease than in grades 1–2 disease (P?=?0.011) and significantly and inversely correlated with Ki-67 LI (ρ?=??0.59, P?=?0.0002). Low ADCs (<1.10?×?10^?3 mm²/s) were significantly associated with shorter CSS (P?=?0.039). Multivariate analysis of preoperative variables identified ADC and MRI-based clinical T stage as independent indicators of shorter CSS; the patients were stratified into high-risk (8 patients with low ADC and at least clinical T3) and low-risk (26 patients with high ADC or not more than clinical T2) groups with 3-year CSS rates of 43 % and 93 % (P?=?0.0003).

Conclusions

Our preliminary data suggest the potential role of ADC as a quantitative biomarker reflecting the aggressiveness of UUT-UCC. ADC might be useful for preoperative risk stratification of UUT-UCC patients.

Key Points

? Diffusion-weighted MRI offers new information about the aggressiveness of urinary tract cancers. ? The apparent diffusion coefficient acts as a quantitative biomarker for upper urinary tract cancers. ? ADC inversely correlates with immunohistochemical and histological grading of UUT-UCC. ? ADC offers a prognosis for UUT-UCC patients treated with nephroureterectomy.     

Value of DW-MRI ADC quantification of colonic wall lesions in differentiation of inflammatory bowel disease and colorectal carcinoma

Purpose

The purpose of our study was to assess the efficiency of diffusion-weighted magnetic resonance imaging (DW-MRI) and the quantification of apparent diffusion coefficient (ADC) values in differentiating colorectal carcinoma from colonic inflammatory bowel disease (IBD) in cases with isolated colonic wall lesions and uncertain clinical and radiologic diagnostic criteria.

Methods

The study comprised 58 patients with segmental or focal isolated colonic wall thickening. All lacked satisfactory clinical–radiological findings for etiology determination. The mean ADC values of the thickened colonic walls were retrospectively compared with final histopathologic diagnoses. Receiver operating characteristic (ROC) curve analysis was used to determine the ADC cutoff value for differentiation.

Results

Mean ADC value in the colorectal carcinoma group was significantly lower than that in the IBD group: n = 27, 1.02 ± 0.26 × 10^?3 mm²/s; and n = 31, 1.53 ± 0.19 × 10^?3 mm²/s, respectively (P < 0.001). Cutoff ADC value for differentiating colorectal carcinoma from IBD was calculated as 1.39 × 10^?3 mm²/s, with 83.9 % sensitivity and 85.2 % specificity.

Conclusion

ADC measurement of the involved colonic wall segments with DW-MRI has the potential to differentiate isolated colonic IBD from colorectal carcinoma in cases in which clinical–radiologic findings are insufficient for a definitive diagnosis.     

Correlations between diffusion-weighted imaging and breast cancer biomarkers

Objective

We evaluated whether the apparent diffusion coefficient (ADC) provided by diffusion-weighted imaging (DWI) varies according to biological features in breast cancer.

Methods

DWI was performed in 190 patients undergoing dynamic contrast-enhanced magnetic resonance imaging (MRI) for local staging. For each of the 192 index cancers we studied the correlation between ADC and classical histopathological and immunohistochemical breast tumour features (size, histological type, grade, oestrogen receptor [ER] and Ki-67 expression, HER2 status). ADC was compared with immunohistochemical surrogates of the intrinsic subtypes (Luminal A; Luminal B; HER2-enriched; triple-negative). Correlations were analysed using the Mann–Whitney U and Kruskal–Wallis H tests.

Results

A weak, statistically significant correlation was observed between ADC values and the percentage of ER-positive cells (-0.168, P?=?0.020). Median ADC values were significantly higher in ER-negative than in ER-positive tumours (1.110 vs 1.050?×?10^-3?mm²/s, P?=?0.015). HER2-enriched tumours had the highest median ADC value (1.190?×?10^-3?mm²/s, range 0.950–2.090). Multiple comparisons showed that this value was significantly higher than that of Luminal A (1.025?×?10^-3?mm²/s [0.700–1.340], P?=?0.004) and Luminal B/HER2-negative (1.060?×?10^-3?mm²/s [0.470–2.420], P?=?0.008) tumours. A trend towards statistical significance (P?=?0.018) was seen with Luminal B/HER2-positive tumours.

Conclusions

ADC values vary significantly according to biological tumour features, suggesting that cancer heterogeneity influences imaging parameters.

Key Points

? DWI may identify biological heterogeneity of breast neoplasms. ? ADC values vary significantly according to biological features of breast cancer. ? Compared with other types, HER2-enriched tumours show highest median ADC value. ? Knowledge of biological heterogeneity of breast neoplasm may improve imaging interpretation.     

Diffusion-weighted MRI in pretreatment prediction of response to neoadjuvant chemotherapy in patients with breast cancer

Purpose

To evaluate the accuracy of the apparent diffusion coefficient (ADC) provided by diffusion-weighted imaging (DWI) in predicting the response to neoadjuvant chemotherapy (NACT) at baseline in patients according to their breast tumour phenotypes.

Materials & methods

This retrospective study was approved by our institutional review board. One hundred eighteen consecutive women with locally advanced breast cancer who had undergone NACT followed by breast surgery were included. DWI was performed at 1.5 T less than 2 weeks before NACT. We studied the correlation between pretreatment ADC and response in pathology after surgery according to immunohistochemical features and intrinsic subtypes (luminal A, luminal B, HER2-enriched, and triple-negative tumours).

Results

After surgery, the pathologist recognized 24 complete responders (CRps) and 94 non-complete responders (NCRps). No difference was identified between the pretreatment ADCs of the CRp and NCRp patients. There were differences in pretreatment ADCs among the luminal A (1.001 ± 0.143?×?10^?3 mm²/s), luminal B (0.983 ± 0.150?×?10^?3 mm²/s), HER2-enriched (1.132 ± 0.216?×?10^?3 mm²/s), and triple-negative (1.168 ± 0.245?×?10^?3 mm²/s; P?=?0.0003) tumour subtypes. In triple-negative tumours, the pretreatment ADC was higher in NCRp (1.060 ± 0.143?×?10^?3 mm²/s) than in CRp patients (1.227 ± 0.271?×?10^?3 mm²/s; P?=?0.047).

Conclusion

Pretreatment ADC can predict the response of breast cancer to NACT if tumour subtypes are considered. Key Points ? Apparent diffusion coefficient helps clinicians to assess patients with breast cancer. ? Pretreatment ADC is related to tumour grade and hormone receptor status. ? Pretreatment ADC is lower in luminal A and B than in triple-negative tumours. ? Pretreatment ADC is higher in complete than in non-complete responders to neoadjuvant chemotherapy.     

Diffusion weighted imaging of the normal breast: reproducibility of apparent diffusion coefficient measurements and variation with menstrual cycle and menopausal status

Objectives

To establish the reproducibility of apparent diffusion coefficient (ADC) measurements in normal fibroglandular breast tissue and to assess variation in ADC values with phase of the menstrual cycle and menopausal status.

Methods

Thirty-one volunteers (13 premenopausal, 18 postmenopausal) underwent magnetic resonance twice (interval 11–22?days) using diffusion-weighted MRI. ADC_total and a perfusion-insensitive ADC_high (omitting b?=?0) were calculated. Reproducibility and inter-observer variability of mean ADC values were assessed. The difference in mean ADC values between the two phases of the menstrual cycle and the postmenopausal breast were evaluated.

Results

ADC_total and ADC_high showed good reproducibility (r%?=?17.6, 22.4). ADC_high showed very good inter-observer agreement (kappa?=?0.83). The intraclass correlation coefficients (ICC) were 0.93 and 0.91. Mean ADC values were significantly lower in the postmenopausal breast (ADC_total 1.46?±?0.3?×?10^-3?mm²/s, ADC_high 1.33?±?0.3?×?10^-3?mm²/s) compared with the premenopausal breast (ADC_total 1.84?±?0.26?×?10^-3?mm²/s, ADC_high 1.77?±?0.26?×?10^-3?mm²/s; both P?total P?=?0.2, ADC_high P?=?0.24) or between postmenopausal women taking or not taking oestrogen supplements (ADC_total P?=?0.6, ADC_high P?=?0.46).

Conclusions

ADC values in fibroglandular breast tissue are reproducible. Lower ADC values within the postmenopausal breast may reduce diffusion-weighted contrast and have implications for accurately detecting tumours.

Key Points

? ADC values from fibroglandular breast tissue are measured reproducibly by multiple observers. ? Mean ADC values were significantly lower in postmenopausal than premenopausal breast tissue. ? Mean ADC values did not vary significantly with menstrual cycle. ? Low postmenopausal ADC values may hinder tumour detection on DW-MRI.     

Quantitative magnetic resonance imaging (MRI) evaluation of cartilage repair after microfracture (MF) treatment for adult unstable osteochondritis dissecans (OCD) in the ankle: correlations with clinical outcome

Objectives

To quantitatively evaluate cartilage repair after microfracture (MF) for ankle osteochondritis dissecans (OCD) using MRI and analyse correlations between MRI and clinical outcome.

Methods

Forty-eight patients were recruited and underwent MR imaging, including 3D-DESS, T2-mapping and T2-STIR sequences, and completed American Orthopaedic Foot and Ankle Society (AOFAS) scoring. Thickness index, T2 index of repair tissue (RT) and volume of subchondral bone marrow oedema (BME) were calculated. Subjects were divided into two groups: group A (3–12 months post-op), and group B (12–24 months post-op). Student’s t test was used to compare the MRI and AOFAS score between two groups and Pearson’s correlation coefficient to analyse correlations between them.

Results

Thickness index and AOFAS score of group B were higher than group A (P?<?0.001, P?<?0.001). T2 index and BME of group B were lower than group A (P?<?0.001, P?=?0.012). Thickness index, T2 index and BME were all correlated with AOFAS score (r?=?0.416, r?=??0.475, r?=??0.353), but BME was correlated with neither thickness index nor T2 index.

Conclusions

Significant improvement from MF can be expected on the basis of the outcomes of quantitative MRI and AOFAS score. MRI was correlated with AOFAS score. BME is insufficient as an independent predictor to evaluate repair quality, but reduction of BME can improve the patient’s clinical outcome.

Key Points

? Patients with unstable ankle OCD had satisfactory clinical outcome after MF. ? Quantitative MRI correlates with clinical outcome after MF for ankle OCD. ? The reduction of subchondral BME will improve the patient’s clinical outcome. ? Quantitative MRI can monitor the process of cartilage repair over time.     

Feasibility of dynamic stress <Superscript>201</Superscript>Tl/rest <Superscript>99m</Superscript>Tc-tetrofosmin single photon emission computed tomography for quantification of myocardial perfusion reserve in patients with stable coronary artery disease

Purpose

We evaluated the feasibility of dynamic stress ²⁰¹Tl/rest ^99mTc-tetrofosmin SPECT imaging using a cardiac camera equipped with cadmium-zinc-telluride detectors for the quantification of myocardial perfusion reserve (MPR).

Methods

Subjects with stable known or suspected coronary artery disease (CAD) who had undergone or were scheduled to undergo fractional flow reserve (FFR) measurement were prospectively enrolled. Dynamic stress ²⁰¹Tl/rest ^99mTc-tetrofosmin SPECT imaging was performed using a dedicated multiple pinhole SPECT camera with cadmium-zinc-telluride detectors. MPR was derived using Corridor4DM software.

Results

A total of 34 subjects were enrolled (25 men and 9 women; mean age 60.4 years). FFR was measured in 65 coronary arteries with intermediate lesions. The average global MPR was 2.58?±?1.03. Global MPR was associated with the extent of CAD (P?=?0.028) and global summed stress score (r?=??0.60, P?<?0.001). Regional MPR showed a significant correlation with diameter stenosis (r?=??0.57, P?<?0.001), minimum lumen diameter (r?=?0.50, P?<?0.001), summed stress score (r?=??0.52, P?<?0.001) and FFR (r?=?0.52, P?<?0.001). The area under the receiver operating characteristic curve of MPR for the diagnosis of functionally significant stenosis (FFR ≤0.8) was 0.79 (P?<?0.001). The sensitivity and specificity of regional MPR were 67% and 83%, respectively, using a cut-off value of 2.0.

Conclusion

Dynamic stress ²⁰¹Tl/rest ^99mTc-tetrofosmin SPECT imaging and quantification of MPR is feasible in patients with stable CAD. The preliminary results of this study in a small number of patients require confirmation in a larger cohort to determine their implications for bolstering the role of SPECT imaging in the diagnosis and risk prediction of CAD.

     

Diffusion-weighted MR imaging for differentiating borderline from malignant epithelial tumours of the ovary: pathological correlation

Objectives

To investigate diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating borderline from malignant epithelial tumours of the ovary.

Methods

This retrospective study included 60 borderline epithelial ovarian tumours (BEOTs) in 48 patients and 65 malignant epithelial ovarian tumours (MEOTs) in 54 patients. DW imaging as well as conventional MR imaging was performed. Signal intensity on DW imaging was assessed and apparent diffusion coefficient (ADC) value was measured. The results were correlated with histopathology and cell density.

Results

The majority of MEOTs showed high signal intensity on DW imaging, whereas most BEOTs showed low or moderate signal intensity (P?=?0.000). The mean ADC value of the solid components in BEOTs (1.562?±?0.346?×?10^?3 mm²/s) was significantly higher than in MEOTs (0.841?±?0.209?×?10^?3 mm²/s). A threshold value of 1.039?×?10^?3 mm²/s permitted the distinction with a sensitivity of 97.0 %, a specificity of 92.2 % and an accuracy of 96.4 %. There was an inverse correlation between ADC value and cell density (r?=??0.609; P?=?0.0000) which was significantly lower in BEOTs than in MEOTs.

Conclusions

DW imaging is useful for differentiating borderline from malignant epithelial tumours of the ovary.

Key Points

? DW MR imaging is useful for differentiating BEOTs from MEOTs. ? Patients with BEOTs are treated differently from patients with MEOTs. ? Conservative fertility-sparing laparoscopic surgery can be performed in patients with BEOTs. ? BEOTs often affect young women of childbearing age.     

Effect of b value and pre-admission of contrast on diagnostic accuracy of 1.5-T breast DWI: a systematic review and meta-analysis

Objectives

To evaluate the effect of the choice of b values and prior use of contrast medium on apparent diffusion coefficients (ADCs) of breast lesions derived from diffusion-weighted imaging (DWI), and on the discrimination between benign and malignant lesions.

Methods

A literature search of relevant DWI studies was performed. The accuracy of DWI to characterize lesions by using b value ≤600 s/mm² and b value >600 s/mm² was presented as pooled sensitivity and specificity, and the ADC was calculated for both groups. Lesions were pooled as pre- or post-contrast DWI.

Results

Of 198 articles, 26 met the inclusion criteria. Median ADCs were significantly higher (13.2–35.1 %, p?b values ≤600 s/mm² compared to >600 s/mm². The sensitivity in both groups was similar (91 % and 89 %, p?=?0.495) as well as the specificity (75 % and 84 %, p?=?0.237). Contrast medium had no significant effects on the ADCs (p?≥?0.08). The differentiation between benign and malignant lesions was optimal (58.4 %) for the combination of b?=?0 and 1,000 s/mm².

Conclusions

The wide variety of b value combinations applied in different studies significantly affects the ADC of breast lesions and confounds quantitative DWI. If only a couple of b values are used, those of b?=?0 and 1,000 s/mm² are recommended for the best improvement of differentiating between benign and malignant lesions.

Key Points

? The choice of b values significantly affects the ADC of breast lesions. ? Sensitivity and specificity are not affected by the choice of b values. ? b values 0 and 1,000 s/mm ² are recommended for optimal differentiation between benign and malignant lesions. ? Contrast medium prior to DWI does not significantly affect the ADC.     

Diffusion-weighted imaging of focal renal lesions: a meta-analysis

Objectives

Contrast-enhanced MRI can only distinguish to a limited extent between malignant and benign focal renal lesions. The aim of this meta-analysis is to review renal diffusion-weighted imaging (DWI) to compare apparent diffusion coefficient (ADC) values for different renal lesions that can be applied in clinical practice.

Methods

A PubMed search was performed to identify relevant articles published 2004–2011 on renal DWI of focal renal lesions. ADC values were extracted by lesion type to determine whether benign or malignant. The data table was finalised in a consensus read. ADC values were evaluated statistically using meta-regression based on a linear mixed model. Two-sided P value <5 % indicated statistical significance.

Results

The meta-analysis is based on 17 studies with 764 patients. Renal cell carcinomas have significant lower ADC values than benign tissue (1.61?±?0.08?×?10^-3 mm²/s vs 2.10?±?0.09?×?10^-3 mm²/s; P?<?0.0001). Uroepithelial malignancies can be differentiated by lowest ADC values (1.30?±?0.11?×?10^-3 mm²/s). There is a significant difference between ADC values of renal cell carcinomas and oncocytomas (1.61?±?0.08?×?10^-3 mm²/s vs 2.00?±?0.08?×?10^-3 mm²/s; P?<?0.0001).

Conclusions

Evaluation of ADC values can help to determine between benign and malignant lesions in general but also seems able to differentiate oncocytomas from malignant tumours, hence potentially reducing the number of unnecessarily performed nephrectomies.

Key Points

? This meta-analysis assesses the role of diffusion-weighted MRI in renal lesions. ? ADC values obtained by DW MRI have been compared for different renal lesions. ? ADC values can help distinguish between benign and malignant tumours. ? Differentiating oncocytomas from malignant tumours can potentially reduce inappropriate nephrectomies.     

Detection of invasive components in cases of breast ductal carcinoma in situ on biopsy by using apparent diffusion coefficient MR parameters

Objectives

To evaluate whether apparent diffusion coefficient (ADC) parameters could identify invasive components in cases with ductal carcinoma in situ (DCIS) diagnosed by biopsy.

Methods

This retrospective study was approved by the institutional review board and the requirement to obtain informed consent was waived. Sixty-nine consecutive women with 70 lesions diagnosed with DCIS by biopsy underwent breast magnetic resonance (MR) imaging. Multiple regions of interest were placed (as many as possible) within the lesion on ADC maps. The minimum ADC values and the ADC difference values obtained as the difference between minimum and maximum ADCs were evaluated.

Results

Surgical specimens revealed 51 lesions with pure DCIS and the remaining 19 lesions with DCIS with invasive components (DCIS-IC). The minimum ADC value for DCIS-IC (0.99?±?0.04?×?10^?3 mm²/s) was significantly lower than that of pure DCIS (1.15?±?0.03?×?10^?3 mm²/s) (P??=??0.0037). The ADC difference value for DCIS-IC (0.38?±?0.05?×?10^?3 mm²/s) was significantly higher than that of pure DCIS (0.17?±?0.03?×?10^?3 mm²/s). ROC curve analysis for differentiating DCIS-IC from pure DCIS revealed that the area under the curve was 0.71 for minimum ADC value and 0.77 for ADC difference value.

Conclusions

The minimum ADC values and ADC difference values could suggest the presence of invasive components.

Key Points

? Identification of invasive components in DCIS before treatment is clinically important. ? Diffusion-weighted MR imaging can help lesion assessment in breast cancer. ? The minimum ADC value may suggest the presence of an invasive component in DCIS. ? The ADC difference value also suggests the presence of an invasive component in DCIS. ? Preoperative evaluation of diffusion-weighted MR imaging may help surgical planning for DCIS.     

Locally advanced rectal cancer: diffusion-weighted MR tumour volumetry and the apparent diffusion coefficient for evaluating complete remission after preoperative chemoradiation therapy

Objective

To evaluate DW MR tumour volumetry and post-CRT ADC in rectal cancer as predicting factors of CR using high b values to eliminate perfusion effects.

Methods

One hundred rectal cancer patients who underwent 1.5-T rectal MR and DW imaging using three b factors (0, 150, and 1,000 s/mm²) were enrolled. The tumour volumes of T2-weighted MR and DW images and pre- and post-CRT ADC_150–1000 were measured. The diagnostic accuracy of post-CRT ADC, T2-weighted MR, and DW tumour volumetry was compared using ROC analysis.

Results

DW MR tumour volumetry was superior to T2-weighted MR volumetry comparing the CR and non-CR groups (P?<?0.001). Post-CRT ADC showed a significant difference between the CR and non-CR groups (P?=?0.001). The accuracy of DW tumour volumetry (A_z?=?0.910) was superior to that of T2-weighed MR tumour volumetry (A_z?=?0.792) and post-CRT ADC (A_z?=?0.705) in determining CR (P?=?0.015). Using a cutoff value for the tumour volume reduction rate of more than 86.8 % on DW MR images, the sensitivity and specificity for predicting CR were 91.4 % and 80 %, respectively.

Conclusion

DW MR tumour volumetry after CRT showed significant superiority in predicting CR compared with T2-weighted MR images and post-CRT ADC.

Key Points

? Diffusion-weighted MR (DWMR) imaging offers new information about rectal cancer. ? DWMR helps to predict complete remission after chemoradiotherapy in patients with advanced rectal cancer. ? DWMR provides more accurate diagnostic information than T2-weighted MRI. ? Apparent diffusion coefficients can predict CR, but they have certain clinical limitations.     

Routinely performed multiparametric magnetic resonance imaging helps to differentiate common subtypes of renal tumours

Objectives

To retrospectively evaluate the ability of multiparametric magnetic resonance (MR) imaging to differentiate renal tumours.

Methods

MR images from 100 consecutive pathologically proven solid renal tumours without macroscopic fat [57 clear cell, 16 papillary and 7 chromophobe renal cell carcinomas (RCCs), 16 oncocytomas and 4 minimal fat angiomyolipomas (AMLs)] between 2009 and 2012 were evaluated. Two radiologists blinded to pathology results independently reviewed double-echo chemical shift, dynamic contrast-enhanced T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps. Signal intensity index (SII), tumour-to-spleen SI ratio (TSR), ADC ratio, wash-in (WiI) and wash-out indices (WoI) between different phases were calculated.

Results

There were significant differences between papillary RCCs and other renal tumours for arterial WiI (P?<?0.001), initial WoI (P?=?0.006) and ADC ratio (P?<?0.001); between chromophobe RCCs and oncocytomas for TSR (P?=?0.02), parenchymal WiI (P?=?0.03), late WiI (P?=?0.02), initial WoI (P?=?0.03) and late WoI (P?=?0.04); and between clear cell RCCs and oncocytomas for SII (P?=?0.01) and parenchymal WiI (P?=?0.01). Papillary RCCs were distinguished from other tumours (sensitivity 37.5 %, specificity 100 %) and oncocytomas from chromophobe RCCs (sensitivity 25 %, specificity 100 %) and clear cell RCCs (sensitivity 100 %, specificity 94.2 %).

Conclusion

MR imaging provides criteria able to accurately distinguish papillary RCCs from other tumours and oncocytomas from chromophobe and clear cell RCCs.

Key Points

? Multiparametric MR parameters accurately distinguish papillary RCCs with high specificity (100 %). ? Oncocytomas can be distinguished from chromophobe RCCs with high specificity (100 %). ? Oncocytomas can be distinguished from clear cell RCCs with high specificity (94.2 %). ? In oncocytomatosis, imaging follow-up with such parameters analysis could be promoted.     

ECG-gated computed tomography to assess pulmonary capillary wedge pressure in pulmonary hypertension

Objective

We propose a non-invasive method for diagnosing post-capillary pulmonary hypertension (PH group 2). We evaluated pulmonary capillary wedge pressure (PCWP) by studying the left atrium (LA) on thoracic ECG-gated CT compared with right heart catheterisation (RHC).

Methods

We retrospectively studied 54 patients with suspected PH or followed for PH who underwent thoracic ECG-gated CT and RHC within 15 days. The diagnostic accuracy of CT morphological and functional data of the LA for the detection of PCWP >15 mmHg, evaluated by two independent readers, was assessed using correlation and receiver-operating characteristic (ROC) analysis.

Results

Interobserver agreement was high (r?=?0.97–0.99). Correlations were found between PCWP and the morphological criteria of the LA such as anteroposterior diameter at 0 % of the R-R interval (r?=?0.70, P?≤?0.001) as well as at 40 % (r?=?0.69, P?≤?0.001). ROC curves constructed with a threshold value of PCWP?>?15 mmHg showed an area under the curve between 0.88 and 0.91. Significant correlations were found between PCWP and functional criteria of the LA, including distensibility (r?=??0.49, P?≤?0.001) and ejection fraction (r?=??0.58, P?≤?0.001).

Conclusion

Thoracic ECG-gated CT in a PH workup helps distinguish between pre- and post-capillary PH.

Key Points

? Computed tomography may help differentiate the various types of pulmonary hypertension (PH). ? Post-capillary PH group 2 is due to left heart disease. ? Right heart catheterisation is used to separate pre- and post-capillary PH. ? Left atrium anteroposterior diameter measured on CT is of value. ? ECG-gated CT helps clinicians to assess patients with PH non-invasively.