Impact of aortic valve calcification severity and impaired left ventricular function on 3-year results of patients undergoing transcatheter aortic valve replacement

Objectives

To evaluate clinical pre-interventional predictors of 3-year outcome and mortality in high-risk patients with severe aortic valve stenosis treated with transcatheter aortic valve implantation (TAVI).

Methods

Among 367 patients included in the Aachen TAVI registry, 76 patients with baseline dual-source computed tomography (DSCT) for the quantification of aortic valve calcification (AVC) and a 3-year follow-up were identified.

Results

Survival at 30 days was 91 %, and it was 75 %, 66 % and 64 % at 1, 2 years and 3 years, respectively. Non-survivors at 3 years showed a significantly higher Agatston AVC score (2,854?±?1,651) than survivors (1,854?±?961, P?=?0.007). Multivariate analysis including age, logistic EuroScore, glomerular filtration rate, Agatston AVC score, ejection fraction?<?40 %, NYHA class, baseline medication, chronic lung disease and aortic regurgitation revealed that only the Agatston AVC score (P?=?0.03) and impaired left ventricular function (P?=?0.001) was significantly associated with mortality. Patients with Agatston AVC scores >2,000 had a significantly lower 3-year survival rate compared with patients with scores <2,000 (47 % vs 79 %, P?=?0.004).

Conclusions

In patients referred for TAVI, aortic valve calcification severity and impaired left ventricular function may serve as a predictor of long-term mortality. Therefore, AVC scores easily determined from pre-procedural CT datasets may be used for patient risk stratification.

Key Points

? Dual-source CT provides excellent valve delineation before transcatheter aortic valve implantation (TAVI). ? Aortic valve calcification assessed by cardiac CT predicts mortality in TAVI patients. ? Aortic valve calcification scores can help stratify high-risk patients for TAVI. ? Three-year results show good long-term outcome without evidence of structural valve deterioration.     

Thrombus imaging in acute ischaemic stroke using thin-slice unenhanced CT: comparison of conventional sequential CT and helical CT

Objectives

Thin-slice helical unenhanced CT can be used for thrombus imaging but increases radiation exposure. Conventional sequential images obtained by multidetector CT can be reconstructed into thin-slice images. The purpose of this study was to evaluate if conventional sequential unenhanced CT images can replace helical unenhanced CT for thrombus imaging.

Methods

Fifty consecutive patients with acute ischaemic stroke underwent both 5-mm conventional sequential unenhanced CT and helical unenhanced CT. Each of the sequential and helical unenhanced CT images was subsequently reconstructed into four 1.25-mm images. Thrombus volumes and HU were measured semi-automatically using both types of unenhanced CT. Thrombus HU ratio (rHU) was calculated using the HU of the contralateral segment. The intraclass correlation coefficient (ICC) and Bland–Altman plots were used to assess measurement agreement.

Results

The mean rHUs were 1.47?±?0.17 for sequential unenhanced CT and 1.47?±?0.18 helical unenhanced CT (P?=?0.542). The mean thrombus volumes were 124.25?±?125.65?mm³ and 117.84?±?124.32?mm³ on sequential and helical unenhanced CT images, respectively (P?=?0.063). Measurement agreement between thrombus volumes from the two unenhanced CT images was high (ICC?=?0.981).

Conclusions

Thin-slice unenhanced CT images reconstructed from 5-mm sequential images can replace helical unenhanced CT for thrombus imaging in acute ischaemic stroke.

Key Points

? Unenhanced CT is used to evaluate intra-arterial thrombus. ? Thrombus HU and volume measurements using sequential or helical CT are comparable. ? Conventional sequential images can replace helical CT for thrombus imaging. ? Radiation dose for thrombus imaging can be reduced using sequential CT.     

Differentiating primary CNS lymphoma from glioblastoma multiforme: assessment using arterial spin labeling, diffusion-weighted imaging, and 18F-fluorodeoxyglucose positron emission tomography

Introduction

Our purpose was to evaluate the diagnostic performance of arterial spin labeling (ASL) perfusion imaging, diffusion-weighted imaging (DWI), and ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastoma multiformes (GBMs).

Methods

Fifty-six patients including 19 with PCNSL and 37 with GBM were retrospectively studied. From the ASL data, an absolute tumor blood flow (aTBF) and a relative tumor blood flow (rTBF) were obtained within the enhancing portion of each tumor. In addition, the minimum apparent diffusion coefficient (ADCmin) and the maximum standard uptake value (SUVmax) were obtained from DWI and FDG-PET data, respectively. Each of the four parameters was compared between PCNSLs and GBMs using Kruskal–Wallis test. The performance in discriminating between PCNSLs and GBMs was evaluated using the receiver-operating characteristics analysis. Area-under-the-curve (AUC) values were compared among the four parameters using a nonparametric method.

Results

The aTBF, rTBF, and ADCmin were significantly higher in GBMs (mean aTBF ± SD?=?91.6?±?56.0 mL/100 g/min, mean rTBF ± SD?=?2.61?±?1.61, mean ADCmin ± SD?=?0.78?±?0.19?×?10^?3 mm²/s) than in PCNSLs (mean aTBF ± SD?=?37.3?±?10.5 mL/100 g/min, mean rTBF ± SD?=?1.24?±?0.37, mean ADCmin ± SD?=?0.61?±?0.13?×?10^?3 mm²/s) (p?<?0.005, respectively). In addition, SUVmax was significantly lower in GBMs (mean ± SD?=?13.1?±?6.34) than in PCNSLs (mean ± SD?=?22.5?±?7.83) (p?<?0.005). The AUC for aTBF (0.888) was higher than those for rTBF (0.810), ADCmin (0.768), and SUVmax (0.848), although their difference was not statistically significant.

Conclusion

ASL perfusion imaging is useful for differentiating PCNSLs from GBMs as well as DWI and FDG-PET.     

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

Purpose

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.

Methods

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/mm²) during free-breathing. Regions of interest around target lesions on computed b?=?800 s/mm² 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.

Results

ADCs were similar between observers (mean ± SD, 1.15?±?0.28?×?10^-3 mm²/s, observer 1; 1.15?±?0.29?×?10^-3 mm²/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 % ADC_mean, 11.3 % vs 6.7 % ADC_median) and for mid (n?=?14) vs apical (n?=?9) or lower zone (n?=?13) lesions (13.9 %, 2.7 %, 3.8 % respectively ADC_mean; 14.2 %, 2.8 %, 4.7 % respectively ADC_median).

Conclusion

Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours.

Key Points

? 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 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.     

High temporal versus high spatial resolution in MR quantitative pulmonary perfusion imaging of two-year old children after congenital diaphragmatic hernia repair

Objectives

Congenital diaphragmatic hernia (CDH) leads to lung hypoplasia. Using dynamic contrast-enhanced (DCE) MR imaging, lung perfusion can be quantified. As MR perfusion values depend on temporal resolution, we compared two protocols to investigate whether ipsilateral lung perfusion is impaired after CDH, whether there are protocol-dependent differences, and which protocol is preferred.

Methods

DCE-MRI was performed in 36 2-year old children after CDH on a 3 T MRI system; protocol A (n?=?18) based on a high spatial (3.0 s; voxel: 1.25 mm³) and protocol B (n?=?18) on a high temporal resolution (1.5 s; voxel: 2 mm³). Pulmonary blood flow (PBF), pulmonary blood volume (PBV), mean transit time (MTT), and peak-contrast-to-noise-ratio (PCNR) were quantified.

Results

PBF was reduced ipsilaterally, with ipsilateral PBF of 45?±?26 ml/100 ml/min to contralateral PBF of 63?±?28 ml/100 ml/min (p?=?0.0016) for protocol A; and for protocol B, side differences were equivalent (ipsilateral PBF?=?62?±?24 vs. contralateral PBF?=?85?±?30 ml/100 ml/min; p?=?0.0034). PCNR was higher for protocol B (30?±?18 vs. 20?±?9; p?=?0.0294). Protocol B showed higher values of PBF in comparison to protocol A (p always <0.05).

Conclusions

Ipsilateral lung perfusion is reduced in 2-year old children following CDH repair. Higher temporal resolution and increased voxel size show a gain in PCNR and lead to higher perfusion values. Protocol B is therefore preferred.

Key Points

? Quantitative lung perfusion parameters depend on temporal and spatial resolution. ? Reduction of lung perfusion in CDH can be measured with different MR protocols. ? Temporal resolution of 1.5 s with spatial resolution of 2 mm ³ is suitable.     

MRI assessment of experimental gliomas using 17.6 T

Introduction

Using ultra-high-field contrast-enhanced magnetic resonance imaging (MRI), an increase of field strength is associated with a decrease of T ₁ relaxivity. Yet, the impact of this effect on signal characteristics and contrast-enhanced pathology remains unclear. Hence, we evaluated the potential of a 17.6-T MRI to assess contrast-enhancing parts of experimentally induced rat gliomas compared to 3 T.

Methods

A total of eight tumor-bearing rats were used for MRI assessments either at 17.6 T (four rats) or at 3 T (four rats) at 11 days after stereotactic implantation of F98 glioma cells into the right frontal lobe. T ₁-weighted sequences were used to investigate signal-to-noise-ratios, contrast-to-noise-ratios, and relative contrast enhancement up to 16 min after double-dose contrast application. In addition, tumor volumes were calculated and compared to histology.

Results

The 17.6-T-derived contrast-enhancing volumes were 31.5?±?15.4 mm³ at 4 min, 38.8?±?12.7 mm³ at 8 min, 51.1?±?12.6 mm³ at 12 min, and 61.5?±?10.8 mm³ at 16 min after gadobutrol injection. Corresponding histology-derived volumes were clearly higher (138.8?±?8.4 mm³; P?<?0.01). At 3 T, contrast-enhancing volumes were 85.2?±?11.7 mm³ at 4 min, 107.3?±?11.0 mm³ at 8 min, 117.0?±?10.5 mm³ at 12 min, and 129.1?±?10.0 mm³ at 16 min after contrast agent application. Averaged histology-derived volumes (139.1?±?13.4 mm³) in this group were comparable to the 16-min volume (P _{?16 min}?=?0.38). Compared to ultra-high-field MRI, all 3-T-derived volumes were significantly higher (P?<?0.02).

Conclusion

Compared to 3-T-derived images and histology, tumor volumes were underestimated by approximately 50 % at 17.6 T. Hence, contrast-enhanced 17.6-T MRI provided no further benefits in tumor measurement compared to 3 T.     

Intravoxel incoherent motion model-based liver lesion characterisation from three b-value diffusion-weighted MRI

Objective

To evaluate intravoxel incoherent motion (IVIM) model-based liver lesion characterisation from three b-value diffusion-weighted imaging (DWI).

Methods

The 1.5-T DWI data from a respiratory gated spin-echo echo-planar magnetic resonance imaging sequence (b?=?0, 50, 800 s/mm²) were retrospectively analysed in 38 patients with different liver lesions. Conventional apparent diffusion coefficient ADC?=?ADC(0,800) as well as IVIM-based parameters D′?=?ADC(50,800), ADC_low?=?ADC(0,50), and f′ were calculated voxel-wise. Sixty-one regions of interest in hepatocellular carcinomas (HCCs, n?=?24), haemangiomas (HEMs, n?=?11), focal nodular hyperplasias (FNHs, n?=?11), and healthy liver tissue (REFs, n?=?15) were analysed. Group differences were investigated using Student’s t-test and receiver-operating characteristic (ROC) analysis.

Results

Mean values?±?standard deviations of ADC, D′, ADC_low (in 10^-5 mm²/s), and f′ (in %) for REFs/FNHs/HEMs/HCCs were 130?±?11/143?±?27/168?±?16/113?±?25, 104?±?12/123?±?25/162?±?18/102?±?23, 518?±?66/437?±?97/268?±?69/283?±?120, and 18?±?3/14?±?4/6?±?3/9?±?5, respectively. Differences between lesions and REFs were more significant for IVIM-based parameters than for conventional ADC. ROC analysis showed the best discriminability between HCCs and FNHs for ADC_low and f′ and between HEMs and FNHs or HCCs for D′.

Conclusion

Three instead of two b-value DWI enables a numerically stable and voxel-wise IVIM-based analysis for improved liver lesion characterisation with tolerable acquisition time.

Key Points

? Quantitative analysis of diffusion-weighted MRI helps liver lesion characterisation. ? Analysis of intravoxel incoherent motion is superior to apparent diffusion coefficient determination. ? Only three b-values enable separation of diffusion and microcirculation effects. ? The method presented is numerically stable, with voxel-wise results and short acquisition times.     

Intravoxel incoherent motion MR imaging: comparison of diffusion and perfusion characteristics between nasopharyngeal carcinoma and post-chemoradiation fibrosis

Objectives

To compare the intravoxel incoherent motion (IVIM) diffusion and perfusion characteristics of nasopharyngeal carcinoma (NPC) and post-chemoradiation fibrosis to aid in their differentiation.

Methods

Fifty-three (64 %) patients with newly diagnosed NPC and 30 (36 %) patients with biopsy-proven post-chemoradiation fibrosis were recruited into tumour and fibrosis groups respectively. Diffusion-weighted magnetic resonance (MR) imaging was performed using 13 b values (0–1,000 s/mm²). Their respective IVIM parameters (D, pure diffusion; f, perfusion fraction; D*, pseudodiffusion coefficient) were obtained.

Results

D and f were significantly lower in NPC (D?=?0.752?±?0.194?×?10^-3 mm²/s, P <0.001; f?=?0.122?±?0.095, P <0.001) than in fibrosis (D?=?1.423?±?0.364?×?10^-3 mm²/s; f?=?0.190?±?0.120); while D* was significantly higher in NPC (111.366?±?65.528?×?10^-3 mm²/s, P <0.001) than in fibrosis (77.468?±?62.168?×?10^-3 mm²/s). Respective cut-off values with sensitivity, specificity and accuracy were: D?=?1.062?×?10^-3 mm²/s (100 %, 100 %, 100 %); f?=?0.132 (66.0 %, 100 %, 78.3 %); D*?=?85.283?×?10^-3 mm²/s (100 %, 90.7 %, 96.4 %).

Conclusion

NPC and post-chemoradiation fibrosis have distinctive IVIM parameters. IVIM MR imaging is potentially useful in discrimination between NPC and fibrosis.

Key Points

? New MRI techniques offer greater help in the assessment of nasopharyngeal carcinoma. ? Tumour and post-chemoradiation fibrosis have distinctive intravoxel incoherent motion diffusion/perfusion parameters. ? Non-invasive IVIM MRI may help differentiate between tumour and fibrosis. ? Pure diffusion is a robust independent discriminating factor which improves diagnostic confidence.     

Characterization and therapy monitoring of head and neck carcinomas using diffusion-imaging-based intravoxel incoherent motion parameters—preliminary results

Introduction

Using the intravoxel incoherent motion (IVIM) model, diffusion-related coefficient (D) and perfusion-related parameter (f) can be measured. Here, we used IVIM imaging to characterize squamous cell carcinomas of head and neck (HNSCC) and evaluated its application in follow-up after nonsurgical organ preserving therapy.

Methods

Twenty-two patients with locally advanced HNSCC (clinical stage III to IVb) were examined before treatment using eight different b values (b?=?0, 50, 100, 150, 200, 250, 700, 800 s/mm²). All patients were followed for at least 7.5 months after conclusion of therapy. In 16 of these patients, follow-up MRI was available. Using the IVIM approach, f and D were extracted using a bi-exponential fit. For comparison, ADC maps were calculated.

Results

The initial values of f before therapy were located between 5.9 % and 12.9 % (mean: 9.4?±?2.4 %) except for two outliers (f?=?17.9 % and 18.2 %). These two patients exclusively displayed poor initial treatment response. Overall, high initial f (13.1?±?4.1 % vs. 9.1?±?2.4 %) and ADC (1.17?±?0.08?×?10^?3?mm²/s vs. 0.98?±?0.19?×?10^?3?mm²/s) were associated with poor short term outcome (n?=?6) after 7.5 months follow-up. D values before treatment were 0.98?×?10^?3?±?0.18 mm²/s and ADC values were 1.03?×?10^?3?±?0.18 mm²/s. At follow-up, in all primary responders, D (69?±?52 %), f (65?±?46 %), and ADC (68?±?49%) increased.

Conclusions

Our preliminary evaluation indicates that an initial high f may predict poor prognosis in HNSCC. In responders, a significant increase of all IVIM parameters after therapy was demonstrated.     

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.     

Comparison of abdominal MRI with diffusion-weighted imaging to 68Ga-DOTATATE PET/CT in detection of neuroendocrine tumors of the pancreas

Purpose

The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and ⁶⁸Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas.

Methods

Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w?+?DW MRI, T2w?+?contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar’s test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student’s t test.

Results

Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23?=?61 %; observer 2: 15/23?=?65.2 %; p?<?0.05) or CE T1w images (observer 1: 14/23?=?61 %; observer 2: 15/23?=?65.2 %; p?<?0.05). Detection rates of pancreatic NET with PET/CT (both observers: 23/23?=?100 %) were statistically significantly higher than with MRI (p?<?0.05). The mean ADC value of NET (1.02?±?0.26?×?10^?3?mm²/s) was statistically significantly lower than that of normal pancreatic tissue (1.48?±?0.39?×?10^?3?mm²/s).

Conclusion

DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. ⁶⁸Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET.     

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.     

Dynamic contrast–enhanced ultrasonographic (DCE-US) assessment of the early response after combined gemcitabine and HIFU with low-power treatment for the mouse xenograft model of human pancreatic cancer

Purpose

To assess therapeutic efficacy of gemcitabine and HIFU for a mouse model of pancreatic cancer, and the role of DCE-US for predicting early treatment response compared with pathology.

Materials and methods

In 48 PANC-1- nude mice (G1, HIFU_higher power [n?=?14]; G2, gemcitabine [n?=?12]; G3, combined gemcitabine and HIFU_low power [n?=?12]; and G4, control [n?=?10]), pulsed HIFU or gemcitabine therapy was used. DCE-US was performed 1 day before and after first treatment. Seven DCE-US perfusion parameters were obtained. Therapeutic efficacy was estimated using necrotic fraction and apoptosis. Correlation between tumour size and US perfusion parameters was analysed.

Results

Pathology results showed that combined gemcitabine and HIFU using low-power treatment had a more effective response than other treatments, including in the control group, i.e. necrotic fraction: 40.5?±?4.9 vs. 16.9?±?8.0, p?=?0.000 and apoptosis: 44.3?±?29.4 vs. 7.9?±?4.9, p?=?0.002. In this group, US perfusion parameters, including peak intensity (22.6?±?22.6 vs. 9.6?±?6.3, p?=?0.002), AUC (961.8?±?96.9 vs. 884.4?±?91.4, p?=?0.000), and AUC_out (799.9?±?75.6 vs. 747.1?±?77.9, p?=?0.000), had significantly decreased 1 day following first treatment (p?out showed a tendency to decrease in treated groups. Alternatively, peak intensity, AUC, and AUC_out showed a tendency to increase in control group.

Conclusion

Gemcitabine and HIFU were more effective and safer than other treatments. US perfusion parameters were useful for predicting early therapeutic response 1 day following treatment.

Key points

? Recently, treatment of pancreatic cancer has changed based on a multidisciplinary approach. ? Combined gemcitabine_HIFU demonstrated more effective therapeutic response than other treatments. ? DCE-US is useful for predicting early therapeutic response 1 day after treatment. ? In the combined group, PI, AUC, and AUC ^out decreased 1 day after treatment.     

Diffusion-weighted MRI for distinguishing non-neoplastic cysts from solid masses in the mediastinum: problem-solving in mediastinal masses of indeterminate internal characteristics on CT

Objectives

To evaluate the usefulness of diffusion-weighted (DW) magnetic resonance images for distinguishing non-neoplastic cysts from solid masses of indeterminate internal characteristics on computed tomography (CT) in the mediastinum.

Methods

We enrolled 25 patients with pathologically proved mediastinal masses who underwent both thoracic CT and magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI). MRI was performed in patients with mediastinal masses of indeterminate internal characteristics on CT. Two thoracic radiologists evaluated the morphological features and quantitatively measured the net enhancement of the masses at CT. They also reviewed MR images including unenhanced T1- and T2-weighted images, gadolinium-enhanced images and DW images.

Results

The enrolled patients had 15 solid masses and ten non-neoplastic cysts. Although the morphological features and the extent of enhancement on CT did not differ significantly between solid and cystic masses in the mediastinum (P?>?0.05), non-neoplastic cysts were distinguishable from solid masses by showing signal suppression on high-b-value DW images or high apparent diffusion coefficient (ADC) values of more than 2.5?×?10^-3 mm²/s (P?<?0.001). ADC values of non-neoplastic cysts (3.67?±?0.87?×?10^-3 mm²/s) were significantly higher than that of solid masses (1.46?±?0.50?×?10^-3 mm²/s) (P?<?0.001).

Conclusions

DWI can help differentiate solid and cystic masses in the mediastinum, even when CT findings are questionable.

Key Points

? Non-invasive diagnosis of non-neoplastic cysts can save surgical biopsy or excision. ? Conventional CT or MRI findings cannot always provide a confident diagnosis. ? Mediastinal masses can be well-characterised with DWI. ? Non-neoplastic mediastinal cysts show significantly higher ADC values than cystic tumours. ? DWI is useful to determine treatment strategy.     

Diffusion-weighted magnetic resonance imaging of thymoma: ability of the Apparent Diffusion Coefficient in predicting the World Health Organization (WHO) classification and the Masaoka-Koga staging system and its prognostic significance on disease-free survival

Objectives

To evaluate the usefulness of diffusion-weighted magnetic resonance for distinguishing thymomas according to WHO and Masaoka-Koga classifications and in predicting disease-free survival (DFS) by using the apparent diffusion coefficient (ADC).

Methods

Forty-one patients were grouped based on WHO (low-risk vs. high-risk) and Masaoka-Koga (early vs. advanced) classifications. For prognosis, seven patients with recurrence at follow-up were grouped separately from healthy subjects. Differences on ADC levels between groups were tested using Student-t testing. Logistic regression models and areas under the ROC curve (AUROC) were estimated.

Results

Mean ADC values were different between groups of WHO (low-risk?=?1.58?±?0.20?×?10^-3mm²/sec; high-risk?=?1.21?±?0.23?×?10^-3mm²/sec; p?<?0.0001) and Masaoka-Koga (early?=?1.43?±?0.26?×?10^-3mm²/sec; advanced?=?1.31?±?0.31?×?10^-3mm²/sec; p?=?0.016) classifications. Mean ADC of type-B3 (1.05?±?0.17?×?10^-3mm²/sec) was lower than type-B2 (1.32?±?0.20?×?10^-3mm²/sec; p?=?0.023). AUROC in discriminating groups was 0.864 for WHO classification (cut-point?=?1.309?×?10^-3mm²/sec; accuracy?=?78.1 %) and 0.730 for Masaoka-Koga classification (cut-point?=?1.243?×?10^-3mm²/sec; accuracy?=?73.2 %). Logistic regression models and two-way ANOVA were significant for WHO classification (odds ratio[OR]?=?0.93, p?=?0.007; p?<?0.001), but not for Masaoka-Koga classification (OR?=?0.98, p?=?0.31; p?=?0.38). ADC levels were significantly associated with DFS recurrence rate being higher for patients with ADC?≤?1.299?×?10^-3mm²/sec (p?=?0.001; AUROC, 0.834; accuracy?=?78.0 %).

Conclusions

ADC helps to differentiate high-risk from low-risk thymomas and discriminates the more aggressive type-B3. Primary tumour ADC is a prognostic indicator of recurrence.

Key Points

? DW-MRI is useful in characterizing thymomas and in predicting disease-free survival. ? ADC can differentiate low-risk from high-risk thymomas based on different histological composition ? The cutoff-ADC-value of 1.309?×?10 ^-3 mm ² /sec is proposed as optimal cut-point for this differentiation ? The ADC ability in predicting Masaoka-Koga stage is uncertain and needs further validations ? ADC has prognostic value on disease-free survival and helps in stratification of risk

     

Brain atrophy associations with white matter lesions in the ageing brain: the Lothian Birth Cohort 1936

Objective

Cerebral atrophy and white matter lesions (WMLs) are common in older people with common risk factors, but it is unclear if they are related. We investigated whether and to what degree they are related in deep and superficial structures using both volumetric and visual ratings.

Methods

The intracranial, total brain tissue (TBV), cerebrospinal fluid (CSF), ventricular superficial subarachnoid space (SSS), grey matter, normal-appearing white matter, WMLs, and combined CSF, venous sinuses and dural volumes were measured. WMLs were also rated using the Fazekas scale.

Results

Amongst 672 adults (mean age 73?±?1 years), WMLs were associated with global brain atrophy (TBV, β?=??0.43 mm³, P?<?0.01) and specifically with deep (ventricular enlargement, β?=?0.10 mm³, P?=?0.03) rather than superficial (SSS, β?=?0.09 mm³, P?=?0.55) atrophy. A 1 mm³ increase in WML volume was associated with a 0.43 mm³ decrease in TBV and 0.10 mm³ increase in ventricular volume. WMLs were associated with combined CSF + Venous Sinuses + Meninges volumes, but not CSF volume alone. Some of the associations were attenuated after correcting for vascular risk factors. The associations were similar for visually scored WMLs.

Conclusion

WMLs are associated with brain atrophy, primarily with deep brain structures. Measures of brain atrophy should include all intracranial structures when assessing brain shrinkage.

Key Points

? Increasing age-related white matter lesions (WML) are modestly associated with brain atrophy. ? Most associated atrophy affects deep structures (white matter, basal ganglia, etc.). ? This is true whether WMLs are assessed volumetrically or visually scored. ? Precise evaluation of brain atrophy requires assessment of all intracranial tissues.     

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.     

Computed diffusion-weighted imaging using 3-T magnetic resonance imaging for prostate cancer diagnosis

Objective

To assess the efficacy of computed diffusion-weighted images (cDWIs) of b?=?2000 s/mm² (cDWI₂₀₀₀) generated from DWIs of b?=?0 and 1000 for prostate cancer (PCa) diagnosis in comparison with that of measured original DWIs of b?=?1000 (mDWI₁₀₀₀) and b?=?2000(mDWI₂₀₀₀) using 3-T MRI.

Methods

Eighty patients who underwent a preoperative MRI examination, including T2WI and DWI (b?=?0, 1000, 2000 s/mm²), were enrolled in this study. Four combinations of images, protocol A (T2WI alone), B (T2WI + mDWI₁₀₀₀), C (T2WI + mDWI₂₀₀₀) and D (T2WI + cDWI₂₀₀₀), were assessed for their diagnostic capability. Areas under the receiver operating characteristic curve (Az) and diagnostic performance were evaluated, as well as contrast ratios (CR) between cancerous and non-cancerous lesions for each DWI.

Results

The highest CR was obtained with cDWI₂₀₀₀ (0.29?±?0.16). Sensitivity, specificity, accuracy, and Az of the protocols were: A: 66.3 %, 59.4 %, 63.0 %, 0.67; B: 82.6 %, 62.0 %, 72.5 %, 0.80; C: 84.1 %, 66.5 %, 75.5 %, 0.86; D: 83.2 %, 70.0 %, 76.6 %, and 0.84, respectively The specificities and accuracies of protocol C and D were significantly higher than those of protocol B (P?<?0.05).

Conclusion

cDWI₂₀₀₀ appears to be more effective than mDWI₁₀₀₀, and at least as effective as mDWI₂₀₀₀ for PCa diagnosis.

Key Points

? Computed diffusion-weighted MRI with over b1000s/mm ² is useful for prostate cancer detection. ? Computed DWI produces any b-value images with two different b-value images. ? DWI with computed b2000s/mm ² is as valuable as DWI with measured b2000 s/mm ² .     

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.