Do T2-weighted pulse sequences help with the differential diagnosis of enhancing lesions in dynamic breast MRI?

In this study, our purpose was to determine whether T2-weighted images are a useful diagnostic adjunct for lesion characterization in dynamic breast MRI. On a 1.5-T system, 205 enhancing benign and malignant breast tumors were examined. The standardized protocol consisted of a T2-weighted turbo spin echo (TSE) pulse sequence with and without spectral fat suppression (SPIR), followed by a two-dimensional dynamic series with subtraction postprocessing. In 59 cases, T2*-weighted gradient-echo images also were obtained. Two independent radiologists visually rated the lesions (101 malignant, 104 benign) as having either a low or a high signal with respect to the adjacent glandular tissue. To assess age dependency of lesion enhancement velocities and T2-TSE signal intensities, we compared the results for patients at or below the age of 50 (group A), between 40 and 50 (group B), and beyond the age of 50 (group C). In T2-weighted TSE images, breast cancers were iso- or hypointense with respect to breast parenchyma in 87% of cases, whereas fibroadenomas were hyperintense in 71%. Visual assessment of lesion appearance in T2-weighted TSE images allowed to distinguish between fibroadenomas and breast cancers, with a respective sensitivity, specificity, positive predictive value, and negative predictive value of 72%, 75%, 46%, and 90% for young patients; 94%, 66%, 78%, and 89% for the patients between 40 and 50; and 89%, 62%, 85%, and 68% for the patients over 50 years of age. No significant difference was found for the distribution of signal intensities of lesions in T2*-weighted images or in fat-suppressed images. In a contrast-enhancing breast lesion, careful analysis of T2-weighted TSE images can improve differential diagnosis. The accuracy of this criterion varies with age.     

Could the serial determination of Ca15.3 serum improve the diagnostic accuracy of PET/CT? Results from small population with previous breast cancer

Objectives  

A single value of tumor marker elevation is not used for the diagnosis of breast cancer (BC) relapse, whereas the serial measurements which confirm a persistent Ca15.3 increase can represent an early signal of tumor relapse, even if described in asymptomatic patients without any other clinical or instrumental signs of cancer. The aim of this study was to assess the relationship between serial measures of Ca15.3 and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings in patients with already treated BC during follow-up.     

Endorectal 3D T2-weighted 1 mm-slice thickness MRI for prostate cancer staging at 1.5 Tesla: Should we reconsider the indirects signs of extracapsular extension according to the D’Amico tumor risk criteria?

Purpose

To evaluate the accuracy of a 3D-endorectal 1 mm-thick slices MRI acquisition for local staging of low, intermediate and high D’Amico risk prostate cancer (PCa).

Materials and methods

178 consecutive patients underwent a multiparametric MRI protocol prior to radical prostatectomy (RP). T2W images were acquired with the 3D sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE) sequence (5 mn acquisition time). Direct and indirect MRI signs of extracapsular extension (ECE) were evaluated to predict the pT stage. The likelihood of SVI (seminal vesicle invasion) was also assessed.

Results

Histology showed ECE and SVI in 38 (21%) and 12 (7%) cases, respectively. MRI sensitivity and specificity to detect ECE were 55 and 96% if direct signs of ECE were used and 84 and 89% (p < 0.05), if both direct and indirect signs were combined. D’Amico criteria did not influence MRI performance. Sensitivity and specificity for SVI detection were 83% and 99%.

Conclusions

3D data sets acquired with the SPACE sequence provides a high accuracy for local staging of prostate cancer. The use of indirect signs of ECE may be recommended in low D’Amico risk tumors to optimise patient selection for active surveillance or focal therapy.     

Morphological and kinetic characteristics of dynamic contrast-enhanced MRI (DCE-MRI) correlated with histopathological factors of breast cancer: A potential prognostic role of breast MRI?

Purpose

To explore the correlation of morphological and kinetic DCE-MRI features with histopathological prognostic factors of invasive breast cancer.

Material and methods

Fifty-one women with 57 cancerous lesions underwent DCE-MRI prior to surgery. DCE-MRI findings were interpreted with a multifactorial classification system that included morphological (shape, margins and pattern of enhancement) and kinetic characteristics (initial signal increase and post-initial behaviour of the time-signal intensity curve). Each morphological and kinetic parameter was scored with 0, 1 or 2 points and the total score was estimated. Finally each lesion was classified into one of the five categories that correspond to the five ACR BI-RADS categories. Statistical analysis was performed to correlate DCE-MR imaging parameters and histopathological findings using Fisher's exact test and stepwise multiple regression analysis.

Results

Increase of the signal intensity at the initial phase >100% was strongly correlated with positive lymph nodes (p = 0.008, OR 0.054). Types I and II time-signal intensity curves at the post-initial phase were associated with a fourfold increase in the likelihood of progesterone receptors positivity (p = 0.022, OR 4). Finally, high total score was positively correlated with affected lymph nodes (p = 0.033, OR 0.29).There was a trend regarding ill-defined margins of the tumor (p = 0.08) and vascular infiltration and also high score and neural infiltration (p = 0.072).

Conclusion

A multivariate interpretation model for DCE-MRI that includes morphological and kinetic characteristics has prognostic value for invasive breast cancer. Early initial contrast agent uptake and a high overall score are associated with poor prognostic factors.     

The breast lesion excision system (BLES): a novel technique in the diagnostic and therapeutic management of small indeterminate breast lesions?

Objective  

To investigate whether the breast lesion excision system (BLES) could render formal surgery unnecessary in patients with small indeterminate breast lesions.     

Do structural changes in the tumour bed after intraoperative radiotherapy (IORT) of breast cancer complicate the evaluation of mammograms in a long-term follow-up?

The purpose of the study was to assess whether postoperative changes in the tumour bed after intraoperative radiotherapy (IORT) with low-energy X-rays complicate the mammographic evaluation. 54 patients receiving breast-conserving surgery and IORT were compared to a control group of 48 patients with conventional breast-conserving treatment. All patients were included in routine follow-ups (≥3 years) with mammography accompanied by ultrasound. By retrospective consensus reading the mammographic changes in the tumour bed were classified as absent, low or distinct. Using the same grading it was classified whether mammographic evaluation was complicated due to postoperative changes. Focusing the yearly follow-ups within a period of four years, distinct changes were found significantly more often after IORT (52-62% vs. 7-30%). After IORT the evaluation was significantly more often distinctly complicated in each follow-up, except for year 1 (16-21% vs. 0-8%). In the IORT group the distribution of findings was nearly stable over time. In the control group it changed over time and a distinctly complicated evaluation was no longer seen in the follow-ups of years 3 and 4. Overall, further non-routine diagnostic procedures due to unclear findings in the tumour bed became necessary in 7% (IORT) vs. 8% (control group) of the patients (p=0.86). Evaluation of mammograms is complicated after IORT. In contrast to conventionally treated patients postoperative changes and difficulties of evaluation do not decrease over time. Overall, after IORT the diagnostic uncertainty does not seem to be increased in ultrasound supported mammographic follow-ups. The topic needs further evaluation with larger study samples.     

Multi-detector row helical CT in preoperative assessment of small (< or = 1.5 cm) liver metastases: is thinner collimation better?

PURPOSE: To determine the inferiormost extent of the anterosuperior labral variants on conventional transverse MR images. MATERIALS AND METHODS: We reviewed transverse MR images in 50 consecutive patients with a sublabral foramen or Buford complex at arthroscopy. Images were randomly mixed with those of 58 patients with either a normal labrum (n = 20) or an anterior labral tear (n = 38) at arthroscopy. MR imaging was fat suppressed fast spin echo intermediate or T2 weighted (repetition time msec/effective echo time msec, 1,800-3,000/30-102). Two radiologists evaluated by means of consensus the anterior labrum while blinded to patient history and arthroscopic results. Transverse images obtained through the glenoid fossa were totalled to determine the midpoint. Sensitivity, specificity, and accuracy of MR for depicting a sublabral foramen or Buford complex were calculated along with 95% CIs, by using surgical findings as the reference standard. RESULTS: The sensitivity of MR for diagnosing a sublabral foramen or Buford complex was 0.94 (47 of 50 patients, 95% CI: 0.87, 1.00), specificity was 0.80 (16 of 20 patients, 95% CI: 0.62, 0.97), and accuracy was 0.90 (63 of 70 patients, 95% CI: 0.82, 0.97). The anterior labrum was abnormal on the first transverse section inferior to the midpoint in nine (18%) patients. The labrum was also abnormal on the second section below the midpoint in three (6%) patients. Because of the anterior tilt of the scapula, the midpoint was near the anterior glenoid notch at about the position between 2- and 3-o'clock. CONCLUSION: The labrum may be unattached or absent on the first two transverse images obtained below the midpoint.     

Clinical utility of apparent diffusion coefficient (ADC) values in patients with prostate cancer: Can ADC values contribute to assess the aggressiveness of prostate cancer?

Purpose

To retrospectively evaluate the relationship between apparent diffusion coefficient (ADC) values and Gleason score (GS) in prostate cancer.

Methods

A total of 60 patients who underwent radical prostatectomy for clinically localized prostate cancer were selected for this study. Diffusion‐weighted magnetic resonance (MR) images were obtained using a 1.5 T system. ADC values were analyzed between three groups: GS of 6 or less (n = 7); GS of 7 (n = 37); and GS of 8 or higher (n = 16). ADC values of the three GS groups were statistically analyzed in order to determine the relationship with GS. In the 37 patients with GS = 7 the difference in ADC values between GS 3+4 and GS 4+3 was analyzed.

Results

Median ADC values (10^?3 mm²/s) of the three GS groups were 1.04 (GS = 6 or less), 0.867 (GS = 7), and 0.729 (GS = 8 or higher). Although there was considerable overlap among the groups, the differences in ADC were statistically significant (P < 0.0001). There was a significant inverse correlation between GS and ADC values (z = ?0.437, P < 0.0005). Median ADC values (10^?3 mm²/s) of GS 3+4 and GS 4+3 patients were 0.88 and 0.814, respectively (P < 0.05).

Conclusion

ADC values showed a negative correlation with GS. Pathologically, however, there was considerable intrasubject heterogeneity. J. Magn. Reson. Imaging 2011;33:167–172. © 2010 Wiley‐Liss, Inc.

     

Locally advanced rectal cancer: is diffusion weighted MRI helpful for the identification of complete responders (ypT0N0) after neoadjuvant chemoradiation therapy?

Objectives

To determine retrospectively the additional value of DWI-MRI toT2-MRI for predicting complete response (ypT0N0 = CR) after chemoradiation-therapy (CRT) in locally advanced rectal cancer.

Methods

Seventy locally advanced rectal cancer patients underwent CRT followed by restaging MRI and resection. Two readers with different experience levels independently scored T2 images for CR and, in a second reading, combined T2 and DWI. A 5-point confidence-level score was used to generate ROC curves. Areas under the ROC curves (AUC) and interobserver agreement were compared for both readings. Histology served as reference standard.

Results

The interobserver agreement increased after addition of DWI from 0.35 to 0.58 but the AUC improved only for the experienced reader (0.77 to 0.89, p?=?0.005 vs. 0.74 to 0.70, p?>?0.05). Sensitivity and NPV improved from 20-30 % to 40-70 %, respectively 88 % to 91-95 %. Specificity and PPV improved only for the experienced reader (87 to 93 % respectively 27 to 63 %).

Conclusion

Adding DWI to T2-MRI improves consistency between readers and has potential to improve readers’ accuracy dependent on his/her experience. DWI could be of additional value, particularly in ruling out CR (high NPV), but considering the sub-optimal PPV one should be cautious about relying solely on MRI for the clinical decision to offer a wait-and-see strategy.

Key Points

? Diffusion-weighted magnetic resonance imaging is increasingly used to assess rectal tumours ? Adding DWI to T2-MRI potentially improves diagnostic accuracy for identifying complete responders ? Adding DWI to T2-MRI improves consistency among readers with different experience levels. ? This combination can help rule out complete tumour response. ? Patients should not be selected for wait-and-see strategies by MRI alone.     

Cross sections of the Ar(d,α)Cl, Ar(d,α)Cl, and Ar(d,p)Ar nuclear reactions below 8.4 MeV

We have measured the cross section for production of the medically interesting isotope ^34mCl, along with ³⁸Cl and ⁴¹Ar, using deuteron bombardments of ³⁶Ar and ⁴⁰Ar below 8.4 MeV. ALICE/ASH analytical codes were employed to determine the shape of nuclear excitation functions, and experiments were performed using the University of Wisconsin tandem electrostatic accelerator to irradiate thin targets of argon gas.     

Less G(2) arrest in irradiated cells of breast cancer patients than in female controls: a contribution to their enhanced chromosomal radiosensitivity?

PURPOSE: To determine if the efficacy of G(2) checkpoint control (measured as the degree of mitotic inhibition) was reduced in breast cancer patients (n=129) compared with healthy controls (n=105) after exposure of lymphocytes to X-rays. We had previously shown that the average level of radiation-induced chromosome damage was higher in G(2) lymphocytes of these patients than in the controls, and it was proposed that this was a marker of low penetrance predisposition to cancer. MATERIALS AND METHODS: Proliferating lymphocytes were X-irradiated (50 cGy) and sampled at 90 min post-irradiation, which was the time of maximum mitotic inhibition of G(2) cells, expressed as the extent of reduction in the mitotic index in irradiated compared with unirradiated cells. RESULTS: Repeated measurements on 28 controls showed that there were reproducible differences in mitotic inhibition between individuals. Inhibition was significantly greater in female than in male controls (p=0.014), but less in patients than in female controls (p=0.009). There was a weak inverse correlation between the extent of inhibition and the amount of chromosome damage in all females (r=-0.15, p=0.043). CONCLUSIONS: The lesser mitotic inhibition in patients than in female controls might contribute to their greater mean G(2) chromosomal radiosensitivity. However, this hypothesis is not easily reconciled with other observations that (1) the significant difference in inhibition between the sexes in controls was not accompanied by any gender difference in radiosensitivity and (2) there was an inverse correlation between inhibition and age in controls, yet no age-related increase in radiosensitivity. There might, therefore, be no causal relationship between G(2) mitotic inhibition and chromosomal radiosensitivity.     

Breast imaging reporting and data system (BI-RADS) or French “classification ACR”: What tool for what use? A point of view

The American College of Radiology Task Force on Breast Cancer published in 2003 the fourth edition of BI-RADS for Mammography. It is a lexicon of mammography terms including illustrations of each feature described, followed by a reporting format with assessment categories according to the degree of concern. The aim is to reduce inconsistencies in mammography reports and recommendations for assessment, to facilitate outcome monitoring and to allow each radiologist to audit his own mammography practice. In France, the Société Fran?aise de Radiologie acquired the rights to translate BI-RADS, word for word and without adaptation or influence. The last edition was published in 2004. Simultaneously, French Haute Autorité de Santé and National Committee for Breast Cancer Screening proposed to all community practice mammography facilities a classification of detected abnormalities stating more clearly than BI-RADS do which feature has to be included in such and such assessment category and how to manage it. This "classification ACR" is adapted from BI-RADS but strongly influenced by the context of the French nationwide screening programme, and by European recommendations to limitate undesirable risks of screening such as false positive and overdiagnosis. The differences between the two systems are discussed.     

High-resolution three-dimensional diffusion-weighted imaging of middle ear cholesteatoma at 3.0 T MRI: Usefulness of 3D turbo field-echo with diffusion-sensitized driven-equilibrium preparation (TFE–DSDE) compared to single-shot echo-planar imaging

Objective

To prospectively evaluate the usefulness of a newly developed high-resolution three-dimensional diffusion-weighted imaging method, turbo field-echo with diffusion-sensitized driven-equilibrium (TFE–DSDE) in diagnosing middle-ear cholesteatoma by comparing it to conventional single-shot echo-planar diffusion-weighted imaging (SS-EP DWI).

Materials and methods

Institutional review board approval and informed consent from all participants were obtained. We studied 30 patients with preoperatively suspected acquired cholesteatoma. Each patient underwent an MR examination including both SS-EP DWI and DSDE-TFE using a 3.0 T MR scanner. Images of the 30 patients (60 temporal bones including 30 with and 30 without cholesteatoma) were reviewed by two independent neuroradiologists. The confidence level for the presence of cholesteatoma was graded on a scale of 0–2 (0 = definite absence, 1 = equivocal, 2 = definite presence). Interobserver agreement as well as sensitivity, specificity, and accuracy for detection were assessed for the two reviewers.

Results

Excellent interobserver agreement was shown for TFE–DSDE (κ = 0.821) whereas fair agreement was obtained for SS-EP DWI (κ = 0.416). TFE–DSDE was associated with significantly higher sensitivity (83.3%) and accuracy (90.0%) compared to SS-EP DWI (sensitivity = 35.0%, accuracy = 66.7%; p < 0.05). No significant difference was found in specificity (96.7% for TFE–DSDE, 98.3% for SS-EP DWI)

Conclusion

With increased spatial resolution and reduced susceptibility artifacts, TFE–DSDE improves the accuracy in diagnosing acquired middle ear cholesteatomas compared to SS-EP DWI.     

How can a massive training artificial neural network (MTANN) be trained with a small number of cases in the distinction between nodules and vessels in thoracic CT?

RATIONALE AND OBJECTIVES: To demonstrate that a massive training artificial neural network (MTANN) can be adequately trained with a small number of cases in the distinction between nodules and vessels (non-nodules) in thoracic computed tomography (CT) images. MATERIALS AND METHODS: An MTANN is a trainable, highly nonlinear filter consisting of a linear-output multilayer artificial neural network model. For enhancement of nodules and suppression of vessels, we used 10 nodules and 10 non-nodule images as training cases for MTANNs. The MTANN is trained with a large number of input subregions selected from the training cases and the corresponding pixels in teaching images that contain Gaussian distributions for nodules and zero for non-nodules. We trained three MTANNs with different numbers (1, 9, and 361) of training samples (pairs of the subregion and the teaching pixel) selected from the training cases. In order to investigate the basic characteristics of the trained MTANNs, we applied the MTANNs to simulated CT images containing various-sized model nodules (spheres) with different contrasts and various-sized model vessels (cylinders) with different orientations. In addition, we applied the trained MTANNs to nontraining actual clinical cases with 59 nodules and 1,726 non-nodules. RESULTS: In the output images for the simulated CT images by use of the MTANNs trained with small numbers (one and nine) of subregions, model vessels were clearly visible and were not removed; thus, the MTANNs were not trained properly. However, in the output image of the MTANN trained with a large number of subregions, various-sized model nodules with different contrasts were represented by light nodular distributions, whereas various-sized model vessels with different orientations were dark and thus were almost removed. This result indicates that the MTANN was able to learn, from a very small number of actual nodule and non-nodule cases, the distinction between nodules (spherelike objects) and vessels (cylinder-like objects). In nontraining clinical cases, the MTANN was able to distinguish actual nodules from actual vessels in CT images. For 59 actual nodules and 1,726 non-nodules, the performance of the MTANN decreased as the number of training samples (subregions) in each case decreased. CONCLUSIONS: The MTANN can be trained with a very small number of training cases (10 nodules and 10 non-nodules) in the distinction between nodules and non-nodules (vessels) in CT images. Massive training by scanning of training cases to produce a large number of training samples (input subregions and teaching pixels) would contributed to a high generalization ability of the MTANN.