Can unenhanced MRI of the breast replace contrast-enhanced MRI in assessing response to neoadjuvant chemotherapy?

BACKGROUND: The goals of neoadjuvant chemotherapy (NAC) are to reduce tumor volume and to offer a prognostic indicator in assessing treatment response. Contrast-enhanced magnetic resonance imaging (CE-MRI) is an established method for evaluating response to NAC in patients with breast cancer. PURPOSE: To validate the role of unenhanced MRI (ue-MRI) compared to CE-MRI for assessing response to NAC in women with breast cancer. MATERIAL AND METHODS: Seventy-one patients with ongoing NAC for breast cancer underwent MRI before, during, and at the end of NAC. Ue-MRI was performed with T2-weighted sequences with iterative decomposition of water and fat and diffusion-weighted sequences. CE-MRI was performed using three-dimensional T1-weighted sequences before and after administration of gadobenate dimeglumine. Two blinded observers rated ue-MRI and CE-MRI for the evaluation of tumor response. Statistical analysis was performed to compare lesion size and ADC values changes during therapy, as well as inter-observer agreement. RESULTS: There were no statistically significant differences between ue-MRI and CE-MRI sequences for evaluation of lesion size at baseline and after every cycle of treatment ( P > 0.05). The mean tumor ADC values at baseline and across the cycles of NAC were significantly different for the responder group. CONCLUSION: Ue-MRI can achieve similar results to CE-MRI for the assessment of tumor response to NAC. ADC values can differentiate responders from non-responders.

MRI-guided treatment in the breast.

In the last decades, an increasing interest has developed towards non-invasive breast lesion treatments, which offer advantages such as the lack of surgery-related complications, better cosmetic outcomes, and less psychological distress. In addition, these treatments could be an option for patients with poor health who are not candidates for surgery. Non-surgical ablation can be performed under magnetic resonance (MR) or ultrasound (US) guidance. US is cheaper and easily available, while contrast-enhanced MR is more accurate, ensuring better safety and efficacy for the patient. Overall results of studies about MRI-guided tumor ablation reported complete ablation rates ranging between 20% and 100%. High-intensity focused ultrasound (HIFU or FUS) is the most studied ablative technique and it is already established as a valid technique for ablation of benign and malignant tumors in various organs. Ultrasound-guided FUS is very useful for young patients who refuse surgery or with multiple nodules; however, MR-guided FUS is more sensitive and allows a better evaluation of thermal accumulation within the ablated tissue or the adjacent structures. Most MR-guided FUS studies used a dedicated high-field MR scanner and complete tumor ablation was reported in 17-90% of cases. Other techniques using thermal tissue destruction are radiofrequency ablation (RFA) and laser interstitial thermal therapy (LITT). Only a few studies assessed the efficacy of these treatments, all were performed with open MR devices. RFA showed complete tumor ablation in 30-96% of patients, while LITT in 10-71%, but all the studies had a small number of patients. Cryoablation obtains tissue ablation by a rapid decrease of temperature, with a complete tumor removal reported in 18-52% of cases with MR guidance. No serious complications were reported with these techniques. Currently, breast conservative surgery replaced radical surgery when possible. Therefore, future research should focus on these treatments to shift towards an even less invasive approach to breast neoplasms. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;48:1479-1488.

Digital breast tomosynthesis (DBT): recommendations from the Italian College of Breast Radiologists (ICBR) by the Italian Society of Medical Radiology (SIRM) and the Italian Group for Mammography Screening (GISMa).

This position paper, issued by ICBR/SIRM and GISMa, summarizes the evidence on DBT and provides recommendations for its use. In the screening setting, DBT in adjunct to digital mammography (DM) increased detection rate by 0.5-2.7‰ and decreased false positives by 0.8-3.6% compared to DM alone in observational and double-testing experimental studies. The reduction in recall rate could be less prominent in those screening programs which already have low recall rates with DM. The increase in radiation exposure associated with DM/DBT protocols has been solved by the introduction of synthetic mammograms (sDM) reconstructed from DBT datasets. Thus, whenever possible, sDM/DBT should be preferred to DM/DBT. However, before introducing DBT as a routine screening tool for average-risk women, we should wait for the results of randomized controlled trials and for a statistically significant and clinically relevant reduction in the interval cancer rate, hopefully associated with a reduction in the advanced cancer rate. Otherwise, a potential for overdiagnosis and overtreatment cannot be excluded. Studies exploring this issue are ongoing. Screening of women at intermediate risk should follow the same recommendations, with particular protocols for women with previous BC history. In high-risk women, if mammography is performed as an adjunct to MRI or in the case of MRI contraindications, sDM/DBT protocols are suggested. Evidence exists in favor of DBT usage in women with clinical symptoms/signs and asymptomatic women with screen-detected findings recalled for work-up. The possibility to perform needle biopsy or localization under DBT guidance should be offered when DBT-only findings need characterization or surgery.

Recommendations for breast imaging follow-up of women with a previous history of breast cancer: position paper from the Italian Group for Mammography Screening (GISMa) and the Italian College of Breast Radiologists (ICBR) by SIRM.

Women who were previously treated for breast cancer (BC) are an important particular subgroup of women at intermediate BC risk. Their breast follow-up should be planned taking in consideration a 1.0-1.5 % annual rate of loco-regional recurrences and new ipsilateral or contralateral BCs during 15-20 years, and be based on a regional/district invitation system. This activity should be carried out by a Department of Radiology integrating screening and diagnostics in the context of a Breast Unit. We recommend the adoption of protocols dedicated to women previously treated for BC, with a clear definition of responsibilities, methods for invitation, site(s) of visits, methods for clinical and radiological evaluation, follow-up duration, role and function of family doctors and specialists. These women will be invited to get a mammogram in dedicated sessions starting from the year after the end of treatment. The planned follow-up duration will be at least 10 years and will be defined on the basis of patient's age and preferences, taking into consideration organizational matters. Special agreements can be defined in the case of women who have their follow-up planned at other qualified centers. Dedicated screening sessions should include: evaluation of familial/personal history (if previously not done) for identifying high-risk conditions which could indicate a different screening strategy; immediate evaluation of mammograms by one or, when possible, two breast radiologists with possible addition of supplemental mammographic views, digital breast tomosynthesis, clinical breast examination, breast ultrasound; and prompt planning of possible further workup. Results of these screening sessions should be set apart from those of general female population screening and presented in dedicated reports. The following research issues are suggested: further risk stratification and effectiveness of follow-up protocols differentiated also for BC pathologic subtype and molecular classification, and evaluation of different models of survivorship care, also in terms of cost-effectiveness.

Mammography and MRI for screening women who underwent chest radiation therapy (lymphoma survivors): recommendations for surveillance from the Italian College of Breast Radiologists by SIRM.

Women who underwent chest radiation therapy (CRT) during pediatric/young-adult age (typically, lymphoma survivors) have an increased breast cancer risk, in particular for high doses. The cumulative incidence from 40 to 45 years of age is 13-20 %, similar to that of BRCA mutation carriers for whom contrast-enhanced magnetic resonance imaging (MRI) is recommended. However, in women who underwent CRT, MRI sensitivity is lower (63-80 %) and that of mammography higher (67-70 %) than those observed in women with hereditary predisposition, due to a higher incidence of ductal carcinoma in situ with microcalcifications and low neoangiogenesis. A sensitivity close to 95 % can be obtained only using mammography as an adjunct to MRI. Considering the available evidence, women who underwent CRT before 30 receiving a cumulative dose ≥10 Gy should be invited after 25 (or, at least, 8 years after CRT) to attend the following program: 1. interview about individual risk profile and potential of breast imaging; 2. annual MRI using the same protocol recommended for women with hereditary predisposition; 3. annual bilateral two-view full-field digital mammography or digital breast tomosynthesis (DBT) with synthetic 2D reconstructions. Mammography and MRI can be performed at once or alternately every 6 months. In the case of MRI or contrast material contraindications, ultrasound will be performed instead of MRI. Reporting using BI-RADS is recommended. At the age for entering population screening, the individual risk profile will be discussed with the woman about opting for only mammography/DBT screening or for continuing the intensive protocol.

High-intensity focused ultrasound in breast pathology: non-invasive treatment of benign and malignant lesions.

Breast neoplasms are one of the leading causes of morbidity and mortality in women. Even if surgery is the treatment of choice, other forms of less invasive radical treatment are desirable. High-intensity focused ultrasound is already established as a valid non-invasive technique that ensures tumor ablation in various organs. The use of ultrasound or magnetic resonance guidance allows having some advantages such as the capability to treat tumors in moving organs or the possibility to have a real-time monitoring of the temperature increase. The aim of this paper is to report the use of high-intensity focused ultrasound technique with ultrasound and magnetic resonance guidance for the ablation of breast tumors, including both benign and malignant lesions.

MR-guided high-intensity focused ultrasound: current status of an emerging technology.

The concept of ideal tumor surgery is to remove the neoplastic tissue without damaging adjacent normal structures. High-intensity focused ultrasound (HIFU) was developed in the 1940s as a viable thermal tissue ablation approach. In clinical practice, HIFU has been applied to treat a variety of solid benign and malignant lesions, including pancreas, liver, prostate, and breast carcinomas, soft tissue sarcomas, and uterine fibroids. More recently, magnetic resonance guidance has been applied for treatment monitoring during focused ultrasound procedures (magnetic resonance-guided focused ultrasound, MRgFUS). Intraoperative magnetic resonance imaging provides the best possible tumor extension and dynamic control of energy deposition using real-time magnetic resonance imaging thermometry. We introduce the fundamental principles and clinical indications of the MRgFUS technique; we also report different treatment options and personal outcomes.

Osteoid osteoma: MR-guided focused ultrasound for entirely noninvasive treatment.

PURPOSE: To determine the preliminary feasibility, safety, and clinical efficacy of magnetic resonance (MR)-guided focused ultrasound for the treatment of painful osteoid osteoma. MATERIALS AND METHODS: This prospective institutional review board-approved study involved six consecutive patients (five males and one female; mean age, 21 years) with a diagnosis of osteoid osteoma based on clinical and imaging findings. All patients underwent MR-guided focused ultrasound ablation after providing informed consent. Lesions located in the vertebral body were excluded. The number of sonications and the energy deposition were recorded. Treatment success was determined at 1, 3, and 6 months after treatment. A visual analog scale (VAS) score for pain was used to assess changes in symptoms. MR imaging features of osteoid osteoma (edema, hyperemia, and nidus vascularization) were considered at baseline and at imaging follow-up. RESULTS: Treatment was performed with a mean of 4 sonications ± 1.8 (standard deviation), with a mean energy deposition of 866 J ± 211. No treatment- or anesthesia-related complications occurred. The pre- and posttreatment mean VAS scores significantly differed (7.9 ± 1.4 and 0.0 ± 0.0, respectively). At imaging, the edema and hyperemia associated with osteoid osteoma gradually disappeared in all lesions. However, nidus vascularization still persisted after treatment in four of six patients. CONCLUSION: This limited series demonstrated that MR-guided focused ultrasound treatment of osteoid osteoma can be performed safely with a high rate of success and without apparent treatment-related morbidity.

Persistence of the sciatic artery: a case report of a combined (complete and incomplete) type causing leg ischemia.

Persistent sciatic artery is a very uncommon embryologic vascular variant, with a prevalence of 0.05% based on angiographic studies. Two different types of this anomaly can occur, complete or incomplete, on the basis of the relationship between sciatic artery and femoral artery. Although many of these patients are asymptomatic, it may represent a threat to the viability of the lower extremity because of atherosclerotic degeneration resulting in aneurysmal dilatation, occlusive thrombosis, or embolic phenomena with distal complication. We present a case of a 64-year-old man with combined, complete and incomplete, type of persistent sciatic artery causing ischemic ulcer of the first toe.

Liver metastases from colorectal cancer treated with conventional and antiangiogenetic chemotherapy: evaluation with liver computed tomography perfusion and magnetic resonance diffusion-weighted imaging.

OBJECTIVE: The objectives of the study were to determine whether perfusion computed tomography (CT-p) and magnetic resonance diffusion-weighted imaging (MR-DWI) can allow evaluation of the effects of chemotherapy combined with antiangiogenetic treatment on liver metastases in patients with advanced colorectal cancer and to determine if changes in CT-p and MR-DWI correlate with the response to therapy as assessed by conventional Response Evaluation Criteria in Solid Tumors (RECIST). METHODS: Eighteen patients with liver metastases from colorectal cancer underwent CT-p and MR-DWI before and 6 months after chemotherapy and antiangiogenetic treatment. Lesions were classified according to RECIST criteria (complete response [CR], partial response [PR], stable disease [SD], and progressive disease) and calculations of CT-p parameters including blood flow (BF), blood volume (BV), capillary permeability (CP), and MR-DWI apparent diffusion coefficient (ADC) values were performed; RECIST, CT-p, and MR-DWI measurements at baseline and follow-up were tested for statistically significant differences using the paired-samples t test. Baseline and follow-up perfusion parameters of the lesions were also compared on the basis of therapy response assessed by RECIST criteria using independent-samples t test. P < 0.05 was considered indicative of a statistically significant difference for all statistical test. RESULTS: Six patients (6/18; 33.3%) were classified as PR (), and the remaining 12 (12/18; 66.7%) were classified as SD. On a per-lesion basis, 2 (2/32; 6.3%) cannot be identified at follow-up, 6 (6/32; 18.8%) showed a decrease in size of more than 30%, and 24 (24/32; 75%) were substantially stable in size. No cases of progressive disease were demonstrated at follow-up. No statistically significant differences were demonstrated between PR, CR, and SD lesions for BF (P = 0.19), BV (P = 0.14), and ADC (P = 0.68) measurements, whereas CP was significantly higher in CR and PR lesions (P = 0.038). Considering differences between baseline and follow-up values, no statistically significant differences were noted between PR and CR lesions versus SD lesions for CT-p values (BF: P = 0.77; BV: P = 0.15; CP: P = 0.64). A statistically significant difference between PR and CR lesions and SD lesions was noted for ADC values (P = 0.047). CONCLUSION: Both CT-p and MR-DWI can detect therapy-induced modifications in lesion vascularization before significant changes in size are evident.

Peripheral arterial occlusive disease: diagnostic performance and effect on therapeutic management of 64-section CT angiography.

PURPOSE: To evaluate the diagnostic performance and effect on therapeutic management of 64-section computed tomographic (CT) angiography in the assessment of steno-occlusive disease in patients with peripheral arterial disease (PAD), with conventional digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: The study protocol was approved by the institutional review board, and written informed consent was obtained from all patients. A total of 212 patients with symptomatic PAD underwent CT angiography and subsequent DSA. For stenosis analysis (≥ 70% stenosis), the arterial bed was divided into 35 segments and evaluated by three readers. Interobserver agreement was determined with generalized κ statistics. Accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were calculated. In addition, according to the TransAtlantic Inter-Society Consensus (TASC) Document on Management of Peripheral Arterial Disease guidelines, treatment recommendations based on CT angiographic and DSA findings were compared. McNemar test was used to prove significant differences between CT angiographic and DSA findings. RESULTS: A total of 7420 arterial segments were evaluated, with excellent agreement between readers (κ ≥ 0.928). On a segmental basis, both sensitivity and specificity for stenosis of 70% or more were at least 96% (3072 of 3113 segments and 4141 of 4279 segments, respectively), with an accuracy of 98% (7213 of 7392 segments), a PPV of 96% (3072 of 3187 segments), an NPV of 99% (3141 of 3187 segments), a PLR of 36.7, and an NLR of 0.013. There was no significant difference between CT angiographic and DSA findings (P = .62-.87). In accordance with TASC II guidelines, 49 patients were referred for conservative treatment, 87 underwent endovascular procedures, 38 underwent surgery, and 17 received hybrid treatment. Therapy recommendations based on CT angiographic findings alone were identical to those based on DSA findings in all but one patient. CONCLUSION: The diagnostic performance of 64-section CT angiography is excellent in patients with clinical symptoms of PAD. The results can be used to effectively guide therapeutic decision making in these patients.

Investigation of the longitudinal relaxation rate of blood after gadobenate dimeglumine administration: sequence optimization, dynamic acquisition, and clinical impact for contrast-enhanced MR angiography of the carotid arteries.

OBJECTIVES: To optimize the image acquisition parameters for improved steady-state (SS) contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid arteries with gadobenate dimeglumine. MATERIALS AND METHODS: An inversion recovery fast low-angle shot (IR-FLASH) sequence for ultrafast determination of the longitudinal relaxation rate R1 was first optimized on phantoms and tested against a routine variable repetition time (TR) spin echo sequence used as reference standard. Different combinations of flip angle (FA, between 6 and 14 degrees) and inversion time (between 134 and 9000 milliseconds) were evaluated to achieve the best trade off between speed and accuracy. The optimized sequence was thereafter used in vivo in 5 subjects to determine the time evolution of blood R1 at 1.5 T after administration of gadobenate dimeglumine at 0.1 mmol/kg bodyweight. An optimal FA for angiographic measurement was thereafter derived from the Ernst equation based on experimental values of R1 previously determined in vivo. Finally, steady-state CE-MRA examinations were performed in 20 subjects to evaluate the improved contrast achieved after optimization of the FA for maximal blood signal enhancement. RESULTS: An ultrafast IR-FLASH sequence with a flip angle of 8 degrees and a properly defined set of inversion time values was shown to give in vitro R1 determinations that were in good agreement with those obtained using a routine, time consuming, variable-TR spin echo sequence. The use of this ultrafast IR-FLASH sequence in vivo allowed the blood signal behavior in the carotid arteries after gadobenate dimeglumine administration to be monitored. Using this sequence, the R1 decreased from 8.7±0.96 s⁻¹ at 30 seconds after injection to 3.8±0.24 s⁻¹ at 10 minutes after injection. Based on these data for R1, the optimal FA for SS CE-MRA was calculated to be 18 degrees for a gradient echo acquisition protocol with TR=7.5 milliseconds, when gadobenate dimeglumine is used. Significantly higher blood signal to noise ratio was achieved on SS images acquired using a three-dimensional spoiled gradient echo sequence with a FA of 18 degrees than on corresponding images acquired with a FA of 35 degrees as used typically for intravascular blood pool contrast agents (52.5±8.3 vs. 29.5±6.0; P<0.05, Mann-Whitney U test). CONCLUSION: Detailed experimental knowledge of the in vivo R1 behavior of blood after gadobenate dimeglumine injection and appropriate modification of the acquisition parameters enables improved signal intensity enhancement on steady-state CE-MRA of the carotid arteries.

First-pass and high-resolution steady-state magnetic resonance angiography of the peripheral arteries with gadobenate dimeglumine: an assessment of feasibility and diagnostic performance.

PURPOSE: To assess the feasibility of combined first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) of the peripheral arteries with gadobenate dimeglumine (MultiHance) and to evaluate diagnostic performance relative to digital subtraction angiography (DSA). MATERIALS AND METHODS: A total of 35 patients with symptomatic peripheral arterial occlusive disease (PAOD) underwent FP MRA (repetition time [TR]/echo time [TE]/flip angle [FA]/acquisition time [TA] = 3.5/1.2/30°/14s) at 1.5T after intravenous injection of 10 mL of gadobenate dimeglumine. Thereafter, SS imaging of the calf (TR/TE/FA/TA = 7.5/2.3/20°/40-130s) and femoropopliteal (TR/TE/FA/TA = 7.5/2.3/18°/130-240s) regions was performed after a second injection of 5 mL of gadobenate dimeglumine. All patients underwent conventional DSA. Three readers reviewed separate FP and FP+SS MRA datasets for image quality and presence/absence of clinically relevant PAOD. A fourth independent observer evaluated DSA images. The diagnostic performance (sensitivity, specificity, positive and negative predictive values) achieved with each dataset was determined and compared. Inter-reader agreement was assessed using kappa statistics. RESULTS: The image quality of 134 of 140 vascular regions was optimal or adequate on SS MRA. Inter-reader agreement was good to very good for assessments of FP (κ = 0.725) and combined FP+SS images (κ = 0.866). SS images improved diagnostic confidence in 34 (48.6%) femoropoliteal and 46 (65.7%) crural regions and altered final diagnosis in 8 (11.4%) and 10 (14.3%) regions, respectively. Global diagnostic accuracy increased from 92.9% on FP images to 95.9% on FP+SS images, with significant (P = 0.0384) improvement in the crural region. CONCLUSION: SS MRA of the peripheral arteries is feasible with gadobenate dimeglumine and potentially improves diagnostic performance in patients with symptomatic PAOD.