Diagnostic value of MR elastography in addition to contrast-enhanced MR imaging of the breast—initial clinical results

Objective  

The purpose of the study was to assess the additional value of magnetic resonance (MR) elastography (MRE) to contrast-enhanced (ce) MR imaging (MRI) for breast lesion characterisation.     

Contrast-enhanced MR imaging of the spine: when, why and how? How to optimize contrast protocols in MR imaging of the spine

The optimal protocols and the role of contrast agents in spinal MR imaging are controversial. Although the diagnosis of many common spinal diseases can be reliably achieved by means of unenhanced images, contrast use is often necessary to improve lesion detection and differential diagnosis. The heterogeneity of the different spinal compartments and the wide variety of spinal pathology require tailored imaging strategies. Thus, the rules to achieve optimization of contrast protocols for MR imaging of the spine are frequently very different to those for brain imaging, and depend on the location and site of origin of the lesions in a specific spinal compartment, on the findings of unenhanced imaging, and on the concomitant use of fat-suppression techniques. Furthermore, in most cases, the small size of the examined structures requires a meticulous technique, and the administration of a contrast agent with high relaxivity, such as MultiHance, is advisable to enable the detection of tiny areas of contrast enhancement. The applications and clinical utility of post-contrast MR imaging are discussed with regard to different spinal diseases.     

Automatic ROI construction for analyzing time–signal intensity curve in dynamic contrast-enhanced MR imaging of the breast

Our purpose in this study was to construct a 3-dimensional (3D) region of interest (ROI) for analyzing the time–signal intensity curve (TIC) semi-automatically in dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging of the breast. DCE-MR breast imaging datasets were acquired by a 3.0-Tesla MR system with the use of a 3D fast gradient echo sequence. The essential idea in the new method was to analyze each pixel and to construct an ROI made up of pixels with similar TICs. First, an analyst selected a starting point in the contrast media-enhanced tumor. Second, we calculated Pearson’s correlation coefficients (CCs) between the TIC in the starting coordinate selected by the analyst and the TIC in the other coordinates. Third, ROI pixels were selected if their CC threshold satisfied a level of coefficient variation of the ROI determined by prior research performed in our institution. We made a retrospective review of patients who underwent breast DCE-MR examination for pre-operative diagnosis. To confirm the feasibility of the resulting 3D-ROI from TIC analysis, we compared Fischer’s score obtained from 3D-ROI by applying a new method to a score obtained from a manually selected 2-dimensional (2D) ROI which was used during routine clinical examination. The Fischer’s scores obtained from both the automatically selected 3D-ROI and the manually selected 2D-ROI showed almost equivalent results. Thus, we considered that the new method was comparable to the conventional method. Furthermore, the new method has the potential to be used for evaluation of the extent of tumors.     

Perfusion-index values evaluated by dynamic magnetic resonance imaging in advanced rectal carcinoma. A new predictor of response to preoperative radiochemotherapy?]

PURPOSE: The aim of our study was to evaluate in vivo the influence of tumor microcirculation data on therapy outcome. PATIENTS AND METHODS: Tumor perfusion data of primary rectal carcinoma (n = 14, cT3) who underwent preoperative chemoradiation have been analyzed (Table 1). The perfusion data were acquired at the beginning and at the end of therapy by use of an ultrafast T1-mapping sequence on a whole-body magnetic resonance imager. The gadolinium-DTPA concentration-time-curves were evaluated for arterial blood and tumor before, during and after intravenous constant rate infusion and from that the perfusion index (PI) was calculated. Subsequent resection of the tumors allowed for a correlation of perfusion index values with the pathological classification. RESULTS: Nine patients showed a T downstaging (ypT0-2, group 1), 5 patients did not (ypT3, group 2). The initial mean perfusion index value of group 1 (n = 9) was 8.2 ml/min/100 g (+/- 2) and for group 2 (n = 5) 10.4 ml/min/100 g (+/- 0.4). The difference in perfusion index values before chemoradiation between group 1 and group 2 was significant different (p = 0.012, Mann-Whitney test). The perfusion index value at the end of therapy of group 1 (n = 6) was 9.6 ml/min/100 g (+/- 2.8) and for group 2 (n = 4) 10.7 ml/min/100 g (+/- 1.6). The difference in perfusion index values after chemoradiation between group 1 and group 2 was not significant different (Table 2). CONCLUSION: Our used perfusion index value combines 2 parameters: tumor perfusion and extraction fraction. Therefore a significant negative influence on therapy outcome of high perfusion index values could be explained possibly by areas with a high portion of high perfusion (e.g. av-shunts) and a low extraction fraction (= low exchange of nutrients). However, we could show a significant negative influence of high perfusion index values on therapy outcome (p = 0.012). Because the tumor stage has a significant influence on tumor-free survival, there is a possibility for using initial perfusion index values as a new prognostic factor in rectal carcinoma without sphincter infiltration undergoing a preoperative chemoradiation. To examine this hypotheses a prospective trial is in preparation.     

Combined contrast-enhanced magnetic resonance and diffusion-weighted imaging reading adapted to the “Breast Imaging Reporting and Data System” for multiparametric 3-T imaging of breast lesions

Objective

To develop and assess a combined reading for contrast-enhanced magnetic resonance (CE-MRI) and diffusion weighted imaging (DWI) adapted to the BI-RADS for multiparametric MRI of the breast at 3 T.

Methods

A total of 247 patients with histopathologically verified breast lesions were included in this IRB-approved prospective study. All patients underwent CE-MR and DWI at 3 T. MRIs were classified according to BI-RADS and assessed for apparent diffusion coefficient (ADC) values. A reading method that adapted ADC thresholds to the assigned BI-RADS classification was developed. Sensitivity, specificity, diagnostic accuracy and the area under the curve were calculated. BI-RADS-adapted reading was compared with previously published reading methods in the same population. Inter- and intra-reader variability was assessed.

Results

Sensitivity of BI-RADS-adapted reading was not different from the high sensitivity of CE-MRI (P?=?0.4). BI-RADS-adapted reading maximised specificity (89.4 %), which was significantly higher compared with CE-MRI (P?<?0.001). Previous reading methods did not perform as well as the BI-RADS method except for a logistic regression model. BI-RADS-adapted reading was more sensitive in non-mass-like enhancements (NMLE) and was more robust to inter- and intra-reader variability.

Conclusion

Multiparametric 3-T MRI of the breast using a BI-RADS-adapted reading is fast, simple to use and significantly improves the diagnostic accuracy of breast MRI.

Keypoints

? Multiparametric breast 3-T MRI with BI-RADS-adapted reading improves diagnostic accuracy. ? BI-RADS-adapted reading of CE-MRI and DWI is based on established reporting guidelines. ? BI-RADS-adapted reading is fast and easy to use in routine clinical practice. ? BI-RADS-adapted reading is robust to intra- and inter-reader variability.     

Investigating the prediction value of multiparametric magnetic resonance imaging at 3 T in response to neoadjuvant chemotherapy in breast cancer

Objective

To explore the predictive value of parameters derived from diffusion-weighted imaging (DWI) and contrast-enhanced (CE)-MRI at different time-points during neoadjuvant chemotherapy (NACT) in breast cancer.

Methods

Institutional review board approval and written, informed consent from 42 breast cancer patients were obtained. The patients were investigated before and at three different time-points during neoadjuvant chemotherapy (NACT) using tumour diameter and volume from CE-MRI and ADC values obtained from drawn 2D and segmented 3D regions of interest. Prediction of pathologic complete response (pCR) was evaluated using the area under the curve (AUC) of receiver operating characteristic analysis.

Results

There was no significant difference between pathologic complete response and non-pCR in baseline size measures (p?>?0.39). Diameter change was significantly different in pCR (p?<?0.02) before the mid-therapy point. The best predictor was lesion diameter change observed before mid-therapy (AUC?=?0.93). Segmented volume was not able to differentiate between pCR and non-pCR at any time-point. The ADC values from 3D-ROI were not significantly different from 2D data (p?=?0.06). The best AUC (0.79) for pCR prediction using DWI was median ADC measured before mid-therapy of NACT.

Conclusions

The results of this study should be considered in NACT monitoring planning, especially in MRI protocol designing and time point selection.

Key Points

? Mid-therapy diameter changes are the best predictors of pCR in neoadjuvant chemotherapy. ? Volumetric measures are not strictly superior in therapy monitoring to lesion diameter. ? Size measures perform as a better predictor than ADC values.

     

Alteration of regional cerebral blood flow in patients with chronic pain —Evaluation before and after epidural spinal cord stimulation—

BACKGROUND: Chronic pain is defined as intractable pain caused by abnormal pain transmission or impairment of the pain control system per se. Alteration of regional cerebral blood flow (rCBF) is known to occur under the presence of pain stimulation. Epidural spinal cord stimulation (SCS) is occasionally effective in relieving the symptom. OBJECTIVE: The aim of the current study is to investigate the alteration of rCBF in baseline condition and to find the association between the rCBF change and the efficacy of SCS in chronic pain. METHODS: A total of 18 patients underwent Tc-99m-HMPAO SPECT before and after SCS. Analysis with three-dimensional stereo-tactic surface projections (3D-SSP) with stereo-tactic extraction estimation (SEE) software was adopted to evaluate the rCBF. We assessed the extent score of the abnormal region in each segment (rate of the coordinates with a Z-value that exceeds three kinds of threshold value 2.0, 2.5 and 3.0 in all coordinates within a segment). According to the therapeutic response defined by visual analogue scale, we categorized patients into two groups, the good responder (GR) group (n=12) and poor responder (PR) group (n=6). In the analysis, we compared the extent score in the following two conditions. (1) Comparison between the PR group and normal control group under both baseline condition and after SCS. (2) Comparison between the GR group and normal control group under both baseline condition and after SCS. RESULTS: (1) In the PR group, increased rCBF was observed in left thalamus, bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, the range of these increased rCBF areas localized but remained. Decrease of rCBF was noted in bilateral subcallosal gyrus, superior temporal gyrus (STG) and bilateral anterior cingulate gyrus (ACG). They localized after SCS, but remained. (2) In the GR group, increased rCBF areas were noted in bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, they localized in bilateral precuneus but those of bilateral cerebellum remained. Decreased rCBF area was noted in bilateral subcallosal gyrus, STG and bilateral ACG under the baseline. After SCS, they localized in bilateral subcallosal gyrus and bilateral STG. In contrast, they enlarged in bilateral ACG. CONCLUSION: Chronic pain patients demonstrated abnormal rCBF distribution on both baseline and post SCS conditions. Increased rCBF of thalamus and precuneus under both conditions in the PR group and decreased rCBF of ACG under post SCS conditions in the GR group were characteristic patterns. Tc-99m-HMPAO SPECT with 3D-SSP and SEE analysis is likely objective and effective in monitoring and evaluating therapeutic outcome by SCS in chronic pain. In addition, it provides information that is useful in the selection of SCS candidates.     

Quantitative 201Tl SPET imaging in the follow-up of treatment for brain tumour: a sensitive tool for the early identification of response to chemotherapy?

The aim of this study was to establish if repeated quantitative 201Tl SPET scanning during follow-up of astrocytoma therapy can provide information that is relevant for clinical management. Sixteen consecutive patients, with histopathologically verified highly malignant astrocytoma, were followed during PCV chemotherapy. Imaging with 201Tl SPET and CT was performed repeatedly over 8-16 weeks until treatment discontinuation, with a maximum follow-up of 74 weeks. Tumour uptake volume (TUV), a measure of metabolically active tumour tissue, was calculated from the SPET images. The reliability of early identification of treatment failure, defined as > 25% tumour volume increase, following one course (week 8) and three courses (week 24) of chemotherapy, was calculated for the two imaging methods. 201Tl SPET positive patients (> 25% tumour volume increase) were compared with 201Tl SPET negative patients in terms of time to treatment discontinuation (TTD) and survival time (ST). The patients were followed with a total of 59 SPET examinations, and treatment was continued for a median 27 weeks (range 16-78 weeks). The comparative reliability of SPET and CT showed the highest sensitivity and accuracy for SPET in the early identification of astrocytoma treatment failure at the week 24 assessment. Patients with positive 201Tl SPET after three courses of chemotherapy had a significantly reduced TTD (P = 0.040) but not significantly reduced ST. Of the ten patients who received concomitant radiation and chemotherapy, five had a small (0-10 ml) TUV at the week 24 assessment. Patients with a TUV > 10 ml at this assessment had a shorter TTD (P = 0.016) and a reduced ST (P = 0.024) compared to patients with a TUV < 10 ml. In conclusion, the assessment of progressive disease by quantitative 201Tl SPET appears to provide information on treatment response, earlier and with a higher reliability than CT. Repeated 201Tl SPET scanning during follow-up of astrocytoma treatment is an alternative tool for the early identification of treatment failure.     

Predictive model for contrast-enhanced ultrasound of the breast: Is it feasible in malignant risk assessment of breast imaging reporting and data system 4 lesions?

AIM: To build and evaluate predictive models for contrast-enhanced ultrasound (CEUS) of the breast to distinguish between benign and malignant lesions. METHODS: A total of 235 breast imaging reporting and data system (BI-RADS) 4 solid breast lesions were imaged via CEUS before core needle biopsy or surgical resection. CEUS results were analyzed on 10 enhancing patterns to evaluate diagnostic performance of three benign and three malignant CEUS models, with pathological results used as the gold standard. A logistic regression model was developed basing on the CEUS results, and then evaluated with receiver operating curve (ROC). RESULTS: Except in cases of enhanced homogeneity, the rest of the 9 enhancement appearances were statistically significant (P < 0.05). These 9 enhancement patterns were selected in the final step of the logistic regression analysis, with diagnostic sensitivity and specificity of 84.4% and 82.7%, respectively, and the area under the ROC curve of 0.911. Diagnostic sensitivity, specificity, and accuracy of the malignant vs benign CEUS models were 84.38%, 87.77%, 86.38% and 86.46%, 81.29% and 83.40%, respectively. CONCLUSION: The breast CEUS models can predict risk of malignant breast lesions more accurately, decrease false-positive biopsy, and provide accurate BI-RADS classification.     

Validity of the critical speed to determine blood lactate response and aerobic performance in swimmers aged 10–15 years

Introduction – The aim of this study was to analyze the validity of the critical speed (CS) to determine the speed corresponding to 4 mmol l^–1 of blood lactate (S4) and the speed in a 30 min test (S30min) of swimmers aged 10–15 years.Synthesis of facts – CS, S4 and S30min were determined in 12 swimmers (eight boys and four girls) divided into two groups: 10–12 years and 13–15 years.Conclusion – CS was a good predictor of aerobic performance (S30min) independent of the chronological age, providing practical information about the aerobic performance state of young swimmers.     

Questions of the handsurgeon to the radiologist—a survey on the most common lesions in the hand and the implications of diagnostic tools on their therapy

By the rapid development of imaging techniques, a significant gap developed between the knowledge of the radiologists and that of the hand surgeons on specific indications of the different technical possibilities. The problems to be solved by both specialties together are analyzed. Examples of the most common lesions in the hand like trauma, reflex sympathetic dystrophy, congenital malformation, infection, tumour, rheumatoid and other degenerative processes, nerve compression syndromes etc., are given, and the implications of diagnostic tools on their therapy are discussed.     

Role of magnetic resonance imaging in entrapment and compressive neuropathy—what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: part 2. Upper extremity

The diagnosis of nerve entrapment and compressive neuropathy has been traditionally based on the clinical and electrodiagnostic examinations. As a result of improvements in the magnetic resonance (MR) imaging modality, it plays not only a fundamental role in the detection of space-occupying lesions, but also a compensatory role in clinically and electrodiagnostically inconclusive cases. Although ultrasound has undergone further development in the past decades and shows high resolution capabilities, it has inherent limitations due to its operator dependency. We review the course of normal peripheral nerves, as well as various clinical demonstrations and pathological features of compressed and entrapped nerves in the upper extremities on MR imaging, according to the nerves involved. The common sites of nerve entrapment of the upper extremity are as follows: the brachial plexus of the thoracic outlet; axillary nerve of the quadrilateral space; radial nerve of the radial tunnel; ulnar nerve of the cubital tunnel and Guyon’s canal; median nerve of the pronator syndrome, anterior interosseous nerve syndrome, and carpal tunnel syndrome. Although MR imaging can depict the peripheral nerves in the extremities effectively, radiologists should be familiar with nerve pathways, common sites of nerve compression, and common space-occupying lesions resulting in nerve compression in MR imaging.