Supplemental MRI Screening for Women with Extremely Dense Breast Tissue.

BACKGROUND: Extremely dense breast tissue is a risk factor for breast cancer and limits the detection of cancer with mammography. Data are needed on the use of supplemental magnetic resonance imaging (MRI) to improve early detection and reduce interval breast cancers in such patients. METHODS: In this multicenter, randomized, controlled trial in the Netherlands, we assigned 40,373 women between the ages of 50 and 75 years with extremely dense breast tissue and normal results on screening mammography to a group that was invited to undergo supplemental MRI or to a group that received mammography screening only. The groups were assigned in a 1:4 ratio, with 8061 in the MRI-invitation group and 32,312 in the mammography-only group. The primary outcome was the between-group difference in the incidence of interval cancers during a 2-year screening period. RESULTS: The interval-cancer rate was 2.5 per 1000 screenings in the MRI-invitation group and 5.0 per 1000 screenings in the mammography-only group, for a difference of 2.5 per 1000 screenings (95% confidence interval [CI], 1.0 to 3.7; P<0.001). Of the women who were invited to undergo MRI, 59% accepted the invitation. Of the 20 interval cancers that were diagnosed in the MRI-invitation group, 4 were diagnosed in the women who actually underwent MRI (0.8 per 1000 screenings) and 16 in those who did not accept the invitation (4.9 per 1000 screenings). The MRI cancer-detection rate among the women who actually underwent MRI screening was 16.5 per 1000 screenings (95% CI, 13.3 to 20.5). The positive predictive value was 17.4% (95% CI, 14.2 to 21.2) for recall for additional testing and 26.3% (95% CI, 21.7 to 31.6) for biopsy. The false positive rate was 79.8 per 1000 screenings. Among the women who underwent MRI, 0.1% had either an adverse event or a serious adverse event during or immediately after the screening. CONCLUSIONS: The use of supplemental MRI screening in women with extremely dense breast tissue and normal results on mammography resulted in the diagnosis of significantly fewer interval cancers than mammography alone during a 2-year screening period. (Funded by the University Medical Center Utrecht and others; DENSE ClinicalTrials.gov number, NCT01315015.).

Supplemental Breast MRI for Women with Extremely Dense Breasts: Results of the Second Screening Round of the DENSE Trial.

Background In the first (prevalent) supplemental MRI screening round of the Dense Tissue and Early Breast Neoplasm Screening (DENSE) trial, a considerable number of breast cancers were found at the cost of an increased false-positive rate (FPR). In incident screening rounds, a lower cancer detection rate (CDR) is expected due to a smaller pool of prevalent cancers, and a reduced FPR, due to the availability of prior MRI examinations. Purpose To investigate screening performance indicators of the second round (incidence round) of the DENSE trial. Materials and Methods The DENSE trial (ClinicalTrials.gov: NCT01315015) is embedded within the Dutch population-based biennial mammography screening program for women aged 50-75 years. MRI examinations were performed between December 2011 and January 2016. Women were eligible for the second round when they again had a negative screening mammogram 2 years after their first MRI. The recall rate, biopsy rate, CDR, FPR, positive predictive values, and distributions of tumor characteristics were calculated and compared with results of the first round using 95% CIs and χ2 tests. Results A total of 3436 women (median age, 56 years; interquartile range, 48-64 years) underwent a second MRI screening. The CDR was 5.8 per 1000 screening examinations (95% CI: 3.8, 9.0) compared with 16.5 per 1000 screening examinations (95% CI: 13.3, 20.5) in the first round. The FPR was 26.3 per 1000 screening examinations (95% CI: 21.5, 32.3) in the second round versus 79.8 per 1000 screening examinations (95% CI: 72.4, 87.9) in the first round. The positive predictive value for recall was 18% (20 of 110 participants recalled; 95% CI: 12.1, 26.4), and the positive predictive value for biopsy was 24% (20 of 84 participants who underwent biopsy; 95% CI: 16.0, 33.9), both comparable to that of the first round. All tumors in the second round were stage 0-I and node negative. Conclusion The incremental cancer detection rate in the second round was 5.8 per 1000 screening examinations-compared with 16.5 per 1000 screening examinations in the first round. This was accompanied by a strong reduction in the number of false-positive results. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Moy and Gao in this issue.

Contradiction between amide-CEST signal and pH in breast cancer explained with metabolic MRI.

PURPOSE: Metabolic MRI is a noninvasive technique that can give new insights into understanding cancer metabolism and finding biomarkers to evaluate or monitor treatment plans. Using this technique, a previous study has shown an increase in pH during neoadjuvant chemotherapy (NAC) treatment, while recent observation in a different study showed a reduced amide proton transfer (APT) signal during NAC treatment (negative relation). These findings are counterintuitive, given the known intrinsic positive relation of APT signal to pH. METHODS: In this study we combined APT MRI and 31 P-MRSI measurements to unravel the relation between the APT signal and pH in breast cancer. Twenty-two breast cancer patients were scanned with a 7 T MRI before and after the first cycle of NAC treatment. pH was determined by the chemical shift of inorganic phosphate (Pi). RESULTS: While APT signals have a positive relation to pH and amide content, we observed a direct negative linear correlation between APT signals and pH in breast tumors in vivo. CONCLUSIONS: As differentiation of cancer stages was confirmed by observation of a linear correlation between cell proliferation marker PE/Pi (phosphoethanolamine over inorganic phosphate) and pH in the tumor, our data demonstrates that the concentration of mobile proteins likely supersedes the contribution of the exchange rate to the APT signal.

Safety analysis of holmium-166 microsphere scout dose imaging during radioembolisation work-up: A cohort study.

OBJECTIVE: Radioembolisation is generally preceded by a scout dose of technetium-99m-macroaggregated albumin to estimate extrahepatic shunting of activity. Holmium-166 microspheres can be used as a scout dose (±250 MBq) and as a therapeutic dose. The general toxicity of a holmium-166 scout dose (166Ho-SD) and safety concerns of an accidental extrahepatic deposition of 166Ho-SD were investigated. METHODS: All patients who received a 166Ho-SD in our institute were reviewed for general toxicity and extrahepatic depositions. The absorbed dose in extrahepatic tissue was calculated on SPECT/CT and correlated to clinical toxicities. RESULTS: In total, 82 patients were included. No relevant clinical toxicity occurred. Six patients had an extrahepatic deposition of 166Ho-SD (median administered activity 270 MBq). The extrahepatic depositions (median activity 3.7 MBq) were located in the duodenum (3x), gastric fundus, falciform ligament and the lesser curvature of the stomach, and were deposited in a median volume of 15.3 ml, which resulted in an estimated median absorbed dose of 3.6 Gy (range 0.3-13.8 Gy). No adverse events related to the extrahepatic deposition of the 166Ho-SD occurred after a median follow-up of 4 months (range 1-12 months). CONCLUSION: These results support the safety of 250 MBq 166Ho-SD in a clinical setting. KEY POINTS: • A holmium-166 scout dose is safe in a clinical setting. • Holmium-166 scout dose is a safe alternative for 99m Tc-MAA for radioembolisation work-up. • Holmium-166 scout dose potentially has several benefits over 99m Tc-MAA for radioembolisation work-up.

Anatomic versus Metabolic Tumor Response Assessment after Radioembolization Treatment.

PURPOSE: To assess applicability of metabolic tumor response assessment on 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) after radioembolization (RE) in patients with colorectal liver metastases (CRLM) by comparison with one-dimensional size-based response assessment on MR imaging. MATERIALS AND METHODS: This prospective cohort study comprised 38 patients with CRLM undergoing RE. MR imaging and 18F-FDG PET/CT imaging were performed at baseline, 1 month (n = 38), and 3 months (n = 21). Longest tumor diameter (LTD) reduction on MR imaging at these time points was compared with reduction in total lesion glycolysis (TLG) on 18F-FDG PET/CT. Hepatic response was compared between RECIST and total liver TLG and correlated with overall survival (OS). RESULTS: TLG and LTD were positively correlated in 106 analyzed metastases (38 patients) at 1 month and 58 metastases (22 patients) at 3 months. Agreement was poor, with LTD underestimating TLG response. A significant association with prolonged OS was found in total liver TLG at 1 month (HR 0.64, P < .01) and 3 months (HR 0.43, P < .01). For LTD, a significant association with OS was found at 3 months (HR 0.10, P < .01). Important differences in liver response classification were found, with total liver TLG identifying more patients and situations where there appeared to be treatment benefit compared with RECIST. CONCLUSIONS: TLG response assessment on 18F-FDG PET/CT appears to be more sensitive and accurate, especially at early follow-up, than size-based response assessment on MR imaging in patients with CRLM treated by RE. Semiautomated liver response assessment with total liver TLG is objective, reproducible, rapid, and prognostic.

Additional hepatic 166Ho-radioembolization in patients with neuroendocrine tumours treated with 177Lu-DOTATATE; a single center, interventional, non-randomized, non-comparative, open label, phase II study (HEPAR PLUS trial).

BACKGROUND: Neuroendocrine tumours (NET) consist of a heterogeneous group of neoplasms with various organs of origin. At diagnosis 21% of the patients with a Grade 1 NET and 30% with a Grade 2 NET have distant metastases. Treatment with peptide receptor radionuclide therapy (PRRT) shows a high objective response rate and long median survival after treatment. However, complete remission is almost never achieved. The liver is the most commonly affected organ in metastatic disease and is the most incriminating factor for patient survival. Additional treatment of liver disease after PRRT may improve outcome in NET patients. Radioembolization is an established therapy for liver metastasis. To investigate this hypothesis, a phase 2 study was initiated to assess effectiveness and toxicity of holmium-166 radioembolization (166Ho-RE) after PRRT with lutetium-177 (177Lu)-DOTATATE. METHODS: The HEPAR PLUS trial ("Holmium Embolization Particles for Arterial Radiotherapy Plus 177 Lu-DOTATATE in Salvage NET patients") is a single centre, interventional, non-randomized, non-comparative, open label study. In this phase 2 study 30-48 patients with > 3 measurable liver metastases according to RECIST 1.1 will receive additional 166Ho-RE within 20 weeks after the 4th and last cycle of PRRT with 7.4 GBq 177Lu-DOTATATE. Primary objectives are to assess tumour response, complete and partial response according to RECIST 1.1, and toxicity, based on CTCAE v4.03, 3 months after 166Ho-RE. Secondary endpoints include biochemical response, quality of life, biodistribution and dosimetry. DISCUSSION: This is the first prospective study to combine PRRT with 177Lu-DOTATATE and additional 166Ho-RE in metastatic NET. A radiation boost on intrahepatic disease using 166Ho-RE may lead to an improved response rate without significant additional side-effects. TRIAL REGISTRATION: Clinicaltrials.gov NCT02067988 , 13 February 2014. Protocol version: 6, 30 november 2016.

Eligibility of patients for minimally invasive breast cancer therapy based on MRI analysis of tumor proximity to skin and pectoral muscle.

There is growing interest in minimally invasive breast cancer therapy. Eligibility of patients is, however, dependent on several factors related to the tumor and treatment technology. The aim of this study is to assess the proportion of patients eligible for minimally invasive breast cancer therapy for different safety and treatment margins based on breast tumor location. Patients with invasive ductal cancer were selected from the MARGINS cohort. Semiautomatic segmentation of tumor, skin, and pectoral muscle was performed in Magnetic Resonance images. Shortest distances of tumors to critical organs (ie, skin and pectoral muscle) were calculated. Proportions of eligible patients were determined for different safety and treatment margins. Three-hundred-forty-eight patients with 351 tumors were included. If a 10 mm safety margin to skin and pectoral muscle is required without treatment margin, 72.3% of patients would be eligible for minimally invasive treatment. This proportion decreases to 45.9% for an additional treatment margin of 5 mm. Shortest distances between tumors and critical organs are larger in older patients and in patients with less aggressive tumor subtypes. If a 10 mm safety margin to skin and pectoral muscle is required, more than two-thirds of patients would be eligible for minimally invasive breast cancer therapy.

Liver CT for vascular mapping during radioembolisation workup: comparison of an early and late arterial phase protocol.

OBJECTIVES: To compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols. METHODS: 100 consecutive patients who underwent liver CT between May 2012-January 2015 with early or late arterial phase protocol (n = 50 each, 10- vs. 20-s post-threshold delay) were included. RGA/A4 origin detection rates, assessed by two raters, and contrast-to-noise ratio (CNR) of the hepatic artery relative to the portal vein were compared between the protocols. RESULTS: The first-second rater scored the RGA origin as visible in 58-65 % (specific proportion of agreement 82 %, κ = 0.62); A4 origin in 96-89 % (94 %, κ = 0.54). Thirty-six percent of RGA origins not detectable by DSA were identified on CT. Origin detection rates were not significantly different for early/late arterial phases. Mean CNR was higher in the early arterial phase protocol (1.7 vs. 1.2, p < 0.001). CONCLUSION: A 10-s delay arterial phase CT protocol does not significantly improve detection of small intra- and extrahepatic branches. RGA origin detection requires further optimization, whereas A4/MHA origin detection is adequate, with good inter-rater reproducibility. CT remains important for preprocedural planning, because it may reveal arterial anatomy not discernible on DSA. KEY POINTS: • An early arterial phase does not significantly improve RGA and A4/MHA origin detection. • RGA origin detection (58-65 %) on CT is still suboptimal. • 36 % of RGA origins undetectable on DSA can be identified on CT. • A4/MHA origin detection (89-96 %) on CT is excellent. • Inter-rater reproducibility is good for RGA and A4/MHA origin detection on CT.

High-resolution T2-weighted cervical cancer imaging: a feasibility study on ultra-high-field 7.0-T MRI with an endorectal monopole antenna.

OBJECTIVES: We studied the feasibility of high-resolution T2-weighted cervical cancer imaging on an ultra-high-field 7.0-T magnetic resonance imaging (MRI) system using an endorectal antenna of 4.7-mm thickness. METHODS: A feasibility study on 20 stage IB1-IIB cervical cancer patients was conducted. All underwent pre-treatment 1.5-T MRI. At 7.0-T MRI, an external transmit/receive array with seven dipole antennae and a single endorectal monopole receive antenna were used. Discomfort levels were assessed. Following individualised phase-based B1+ shimming, T2-weighted turbo spin echo sequences were completed. RESULTS: Patients had stage IB1 (n = 9), IB2 (n = 4), IIA1 (n = 1) or IIB (n = 6) cervical cancer. Discomfort (ten-point scale) was minimal at placement and removal of the endorectal antenna with a median score of 1 (range, 0-5) and 0 (range, 0-2) respectively. Its use did not result in adverse events or pre-term session discontinuation. To demonstrate feasibility, T2-weighted acquisitions from 7.0-T MRI are presented in comparison to 1.5-T MRI. Artefacts on 7.0-T MRI were due to motion, locally destructive B1 interference, excessive B1 under the external antennae and SENSE reconstruction. CONCLUSIONS: High-resolution T2-weighted 7.0-T MRI of stage IB1-IIB cervical cancer is feasible. The addition of an endorectal antenna is well tolerated by patients. KEY POINTS: • High resolution T 2 -weighted 7.0-T MRI of the inner female pelvis is challenging • We demonstrate a feasible approach for T 2 -weighted 7.0-T MRI of cervical cancer • An endorectal monopole receive antenna is well tolerated by participants • The endorectal antenna did not lead to adverse events or session discontinuation.

Recommendations for radioembolisation after liver surgery using yttrium-90 resin microspheres based on a survey of an international expert panel.

INTRODUCTION: Guidelines on how to adjust activity in patients with a history of liver surgery who are undergoing yttrium-90 radioembolisation (90Y-RE) are lacking. The aim was to study the variability in activity prescription in these patients, between centres with extensive experience using resin microspheres 90Y-RE, and to draw recommendations on activity prescription based on an expert consensus. METHODS: The variability in activity prescription between centres was investigated by a survey of international experts in the field of 90Y-RE. Six representative post-surgical patients (i.e. comparable activity prescription, different outcome) were selected. Information on patients' disease characteristics and data needed for activity calculation was presented to the expert panel. Reported was the used method for activity prescription and whether, how and why activity reduction was found indicated. RESULTS: Ten experts took part in the survey. Recommendations on activity reduction were highly variable between the expert panel. The median intra-patient range was 44 Gy (range 18-55 Gy). Reductions in prescribed activity were recommended in 68% of the cases. In consensus, a maximum DTarget of 50 Gy was recommended. CONCLUSION: With a current lack of guidelines, large variability in activity prescription in post-surgical patients undergoing 90Y-RE exists. In consensus, DTarget ≤50 Gy is recommended. KEY POINTS: • BSA method does not account for a decreased remnant liver volume after surgery. • In post-surgical patients, a volume-based activity determination method is recommended. • In post-surgical patients, a mean D Target of ≤ 50Gy should be aimed for.

Patient Preferences for Minimally Invasive and Open Locoregional Treatment for Early-Stage Breast Cancer.

BACKGROUND: Noninvasive or minimally invasive treatments are being developed as alternatives to surgery for patients with early-stage breast cancer. Patients' preferences with regard to these new treatments have not been investigated. OBJECTIVES: To assess preferences of patients with breast cancer and of healthy women regarding these new techniques, compared with conventional surgical treatments. METHODS: Six hypothetical breast cancer treatment-outcome scenarios were developed: three standard surgical scenarios (mastectomy, mastectomy with immediate implant-based reconstruction, and breast-conserving therapy [BCT]) and three minimally invasive or noninvasive scenarios (radiofrequency ablation, magnetic resonance-guided high-intensity focused ultrasound ablation, and single-dose ablative radiotherapy). Participants rated treatment-outcome scenarios by visual analogue scale (VAS) and time trade-off (TTO). The Friedman and post hoc Wilcoxon signed-rank tests were used to test whether scores were significantly different from BCT. RESULTS: Seventy-one patients with breast cancer and 50 healthy volunteers participated. Overall, BCT was rated the highest in terms of VAS (0.80) and TTO (0.90) scores. After stratification, BCT ranked the highest in most subgroups, with the exception of healthy individuals, who had given the highest score to ablative boost (VAS, 0.80; TTO, 0.88). Mastectomy with immediate reconstruction was the least preferred in most subgroups. CONCLUSIONS: This study showed no significant preference for minimally invasive treatment for breast cancer. Using hypothetical scenarios, breast cancer survivors attributed the highest scores to BCT, whereas healthy volunteers showed a slight preference for minimally invasive treatments.

Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation.

AIMS: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This study aimed to compare histopathological features of breast cancer after MR-HIFU ablation and RFA. METHODS AND RESULTS: MR-HIFU ablation and RFA were performed in- and ex-vivo. Tumours in six mastectomy specimens were partially ablated with RFA or MR-HIFU. In-vivo MR-HIFU ablation was performed 3-6 days before excision; RFA was performed in the operation room. Tissue was fixed in formalin and processed to haematoxylin and eosin (H&E) and cytokeratin-8 (CK-8)-stained slides. Morphology and cell viability were assessed. Ex-vivo ablation resulted in clear morphological changes after RFA versus subtle differences after MR-HIFU. CK-8 staining was decreased or absent. H&E tended to underestimate the size of thermal damage. In-vivo MR-HIFU resulted in necrotic-like changes. Surprisingly, some ablated lesions were CK-8-positive. Histopathology after in-vivo RFA resembled ex-vivo RFA, with hyper-eosinophilic stroma and elongated nuclei. Lesion borders were sharp after MR-HIFU and indistinct after RFA. CONCLUSION: Histopathological differences between MR-HIFU-ablated tissue and RF-ablated tissue were demonstrated. CK-8 was more reliable for cell viability assessment than H&E when used directly after ablation, while H&E was more reliable in ablated tissue left in situ for a few days. Our results contribute to improved understanding of histopathological features in breast cancer lesions treated with minimally invasive ablative techniques.

First clinical experience with a dedicated MRI-guided high-intensity focused ultrasound system for breast cancer ablation.

OBJECTIVES: To assess the safety and feasibility of MRI-guided high-intensity focused ultrasound (MR-HIFU) ablation in breast cancer patients using a dedicated breast platform. METHODS: Patients with early-stage invasive breast cancer underwent partial tumour ablation prior to surgical resection. MR-HIFU ablation was performed using proton resonance frequency shift MR thermometry and an MR-HIFU system specifically designed for breast tumour ablation. The presence and extent of tumour necrosis was assessed by histopathological analysis of the surgical specimen. Pearson correlation coefficients were calculated to assess the relationship between sonication parameters, temperature increase and size of tumour necrosis at histopathology. RESULTS: Ten female patients underwent MR-HIFU treatment. No skin redness or burns were observed in any of the patients. No correlation was found between the applied energy and the temperature increase. In six patients, tumour necrosis was observed with a maximum diameter of 3-11 mm. In these patients, the number of targeted locations was equal to the number of areas with tumour necrosis. A good correlation was found between the applied energy and the size of tumour necrosis at histopathology (Pearson = 0.76, p = 0.002). CONCLUSIONS: Our results show that MR-HIFU ablation with the dedicated breast system is safe and results in histopathologically proven tumour necrosis. KEY POINTS: • MR-HIFU ablation with the dedicated breast system is safe and feasible • In none of the patients was skin redness or burns observed • No correlation was found between the applied energy and the temperature increase • The correlation between applied energy and size of tumour necrosis was good.

Magnetic Resonance-Guided High Intensity Focused Ultrasound Ablation of Breast Cancer.

This chapter describes several aspects of MR-HIFU treatment for breast cancer. The current and future applications, technical developments and clinical results are discussed. MR-HIFU ablation is under investigation for the treatment of breast cancer, but is not yet ready for clinical implementation. Firstly, the efficacy of MR-HIFU ablation should be investigated in large trials. The existing literature shows that results of initial, small studies are moderate, but opportunities for improvement are available. Careful patient selection, taking treatment margins into account and using a dedicated breast system might improve treatment outcomes. MRI-guidance has proven to be beneficial for the accuracy and safety of HIFU treatments because of its usefulness before, during and after treatments. In conclusion, MR-HIFU is promising for the treatment of breast cancer and might lead to a change in breast cancer care in the future.

MR Imaging as an Additional Screening Modality for the Detection of Breast Cancer in Women Aged 50-75 Years with Extremely Dense Breasts: The DENSE Trial Study Design.

Women with extremely dense breasts have an increased risk of breast cancer and lower mammographic tumor detectability. Nevertheless, in most countries, these women are currently screened with mammography only. Magnetic resonance (MR) imaging has the potential to improve breast cancer detection at an early stage because of its higher sensitivity. However, MR imaging is more expensive and is expected to be accompanied by an increase in the number of false-positive results and, possibly, an increase in overdiagnosis. To study the additional value of MR imaging, a randomized controlled trial (RCT) design is needed in which one group undergoes mammography and the other group undergoes mammography and MR imaging. With this design, it is possible to determine the proportion of interval cancers within each study arm. For this to be an effective screening strategy, the additional cancers detected at MR imaging screening must be accompanied by a subsequent reduction in interval cancers. The Dense Tissue and Early Breast Neoplasm Screening, or DENSE, trial is a multicenter RCT performed in the Dutch biennial population-based screening program (subject age range, 50-75 years). The study was approved by the Dutch Minister of Health, Welfare and Sport. In this study, mammographic density is measured by using a fully automated volumetric method. Participants with extremely dense breasts (American College of Radiology breast density category 4) and a negative result at mammography (Breast Imaging Recording and Data System category 1 or 2) are randomly assigned to undergo additional MR imaging (n = 7237) or to be treated according to current practice (n = 28 948). Participants provide written informed consent before the MR imaging examination, which consists of dynamic breast MR imaging with gadolinium-based contrast medium and is intended to be performed for three consecutive screening rounds. The primary outcome is the difference in the proportions of interval cancers between the study arms. Secondary outcomes are the number of MR imaging screening-detected cancers, proportions of false-positive results, diagnostic yield of MR imaging, tumor characteristics, quality of life, and cost effectiveness.

Assessment of tumor morphology on diffusion-weighted (DWI) breast MRI: Diagnostic value of reduced field of view DWI.

PURPOSE: To compare the diagnostic value of conventional, bilateral diffusion-weighted imaging (DWI) and high-resolution targeted DWI of known breast lesions. MATERIALS AND METHODS: Twenty-one consecutive patients with known breast cancer or suspicious breast lesions were scanned with the conventional bilateral DWI technique, a high-resolution, reduced field of view (rFOV) DWI technique, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) (3.0 T). We compared bilateral DWI and rFOV DWI quantitatively by measuring the lesions' apparent diffusion coefficient (ADC) values. For qualitative comparison, three dedicated breast radiologists scored image quality and performed lesion interpretation. RESULTS: In a phantom, ADC values were in good agreement with the reference values. Twenty-one patients (30 lesions: 14 invasive carcinomas, 10 benign lesions [of which 5 cysts], 3 high-risk, and 3 in situ carcinomas) were included. Cysts and high-risk lesions were excluded from the quantitative analysis. Quantitatively, both bilateral and rFOV DWI measured lower ADC values in invasive tumors than other lesions. In vivo, rFOV DWI gave lower ADC values than bilateral DWI (1.11 × 10(-3) mm(2) /s vs. 1.24 × 10(-3) mm(2) /s, P = 0.002). Regions of interest (ROIs) were comparable in size between the two techniques (2.90 vs. 2.13 cm(2) , P = 0.721). Qualitatively, all three radiologists scored sharpness of rFOV DWI images as significantly higher than bilateral DWI (P ≤ 0.002). Receiver operating characteristic (ROC) curve analysis showed a higher area under the curve (AUC) in BI-RADS classification for rFOV DWI compared to bilateral DWI (0.71 to 0.93 vs. 0.61 to 0.76, respectively). CONCLUSION: Tumor morphology can be assessed in more detail with high-resolution DWI (rFOV) than with standard bilateral DWI by providing significantly sharper images.

Arterial and portal venous liver perfusion using selective spin labelling MRI.

PURPOSE: To investigate the feasibility of selective arterial and portal venous liver perfusion imaging with spin labelling (SL) MRI, allowing separate labelling of each blood supply. METHODS: The portal venous perfusion was assessed with a pulsed EPISTAR technique and the arterial perfusion with a pseudo-continuous sequence. To explore precision and reproducibility, portal venous and arterial perfusion were separately quantified in 12 healthy volunteers pre- and postprandially (before and after meal intake). In a subgroup of 6 volunteers, the accuracy of the absolute portal perfusion and its relative postprandial change were compared with MRI flow measurements of the portal vein. RESULTS: The portal venous perfusion significantly increased from 63 ± 22 ml/100g/min preprandially to 132 ± 42 ml/100g/min postprandially. The arterial perfusion was lower with 35 ± 22 preprandially and 22 ± 30 ml/100g/min postprandially. The pre- and postprandial portal perfusion using SL correlated well with flow-based perfusion (r(2) = 0.71). Moreover, postprandial perfusion change correlated well between SL- and flow-based quantification (r(2) = 0.77). The SL results are in range with literature values. CONCLUSION: Selective spin labelling MRI of the portal venous and arterial blood supply successfully quantified liver perfusion. This non-invasive technique provides specific arterial and portal venous perfusion imaging and could benefit clinical settings where contrast agents are contraindicated. KEY POINTS: • Perfusion imaging of the liver by Spin Labelling MRI is feasible • Selective Spin Labelling MRI assessed portal venous and arterial liver perfusion separately • Spin Labelling based portal venous liver perfusion showed significant postprandial increase • Spin Labelling based portal perfusion correlated well with phase-contrast based portal perfusion • This non-invasive technique could benefit settings where contrast agents are contraindicated.

International consensus on use of focused ultrasound for painful bone metastases: Current status and future directions.

Focused ultrasound surgery (FUS), in particular magnetic resonance guided FUS (MRgFUS), is an emerging non-invasive thermal treatment modality in oncology that has recently proven to be effective for the palliation of metastatic bone pain. A consensus panel of internationally recognised experts in focused ultrasound critically reviewed all available data and developed consensus statements to increase awareness, accelerate the development, acceptance and adoption of FUS as a treatment for painful bone metastases and provide guidance towards broader application in oncology. In this review, evidence-based consensus statements are provided for (1) current treatment goals, (2) current indications, (3) technical considerations, (4) future directions including research priorities, and (5) economic and logistical considerations.

Correction of proton resonance frequency shift MR-thermometry errors caused by heat-induced magnetic susceptibility changes during high intensity focused ultrasound ablations in tissues containing fat.

PURPOSE: In this study, we aim to demonstrate the sensitivity of proton resonance frequency shift (PRFS) -based thermometry to heat-induced magnetic susceptibility changes and to present and evaluate a model-based correction procedure. THEORY AND METHODS: To demonstrate the expected temperature effect, field disturbances during high intensity focused ultrasound sonications were monitored in breast fat samples with a three-dimensional (3D) gradient echo sequence. To evaluate the correction procedure, the interface of tissue-mimicking ethylene glycol gel and fat was sonicated. During sonication, the temperature was monitored with a 2D dual flip angle multi-echo gradient echo sequence, allowing for PRFS-based relative and referenced temperature measurements in the gel and T1 -based temperature measurements in fat. The PRFS-based measurement in the gel was corrected by minimizing the discrepancy between the observed 2D temperature profile and the profile predicted by a 3D thermal model. RESULTS: The HIFU sonications of breast fat resulted in a magnetic field disturbance which completely disappeared after cooling. For the correction method, the 5th to 95th percentile interval of the PRFS-thermometry error in the gel decreased from 3.8°C before correction to 2.0-2.3°C after correction. CONCLUSION: This study has shown the effects of magnetic susceptibility changes induced by heating of breast fatty tissue samples. The resultant errors can be reduced by the use of a model-based correction procedure.

Value of preoperative ultrasound-guided axillary lymph node biopsy for preventing completion axillary lymph node dissection in breast cancer: a systematic review and meta-analysis.

PURPOSE: This meta-analysis was designed to evaluate the utility of preoperative axillary ultrasound combined with US-guided lymph node biopsy if indicated (AUS ± biopsy), in terms of staging the axilla and preventing two-step axillary surgery in the form of sentinel node biopsy (SNB) followed by completion axillary lymph node (ALN) dissection. METHODS: We systematically searched electronic databases for studies that addressed preoperative assessment of ALN status by AUS ± biopsy. A pooled estimate was calculated for the false-negative rate (FNR) of AUS ± biopsy (defined as the proportion of women with a negative AUS ± biopsy result subsequently proven to have a positive axilla) and sensitivity (defined as the proportion of women with a positive AUS ± biopsy result among all women with a tumor positive axilla). RESULTS: The pooled FNR was 25 % (95 % confidence interval [CI] = 24-27) and the pooled sensitivity was 50 % (95 % CI = 43-57). There was substantial heterogeneity across studies for both FNR (I (2) = 69.42) and sensitivity (I (2) = 93.25), which was not explained by between-study differences in biopsy technique, mean/median tumor size, biopsy indication, or study design. Sensitivity was increased in studies with a high prevalence of ALN metastases. CONCLUSIONS: Preoperative axillary ultrasound-guided biopsy is a useful step in the process of axillary staging. Approximately 50 % of women with axillary involvement can be identified preoperatively. Still, one in four women with an ultrasound-guided biopsy-"proven" negative axilla has a positive SNB.