Unenhanced breast magnetic resonance imaging: detection of breast cancer

OBJECTIVE

To evaluate the diagnostic performance of unenhanced MRI (UE-MRI) for malignant breast lesions and its reproducibility.

PATIENTS AND METHODS

We retrospectively included 118 patients who had breast MRI. DWI and STIR images were read in combination and referred to as UE-MRI; the presence or absence of the malignant lesion was noted by two observers. Their results were compared with those of final histopathology or with a two-year negative follow-up for diagnostic performance assessment; ROC curves were built. Diagnostic performance was stratified according to lesion site and size. Interobserver agreement was evaluated through the Cohen's k statistic.

RESULTS

Specificity of STIR and DWI was 99.3% and 95.7% for Reader 1; 99.3% and 96.4% for Reader 2. Sensitivity was 76.5% and 76.5% for Reader 1; 77.5% and 77.6% for Reader 2. The ROC AUC (Reader 1) was 0.869 and 0.844 for STIR and DWI, respectively (p<0.001 both); for Reader 2, values were 0.874 and 0.853 respectively (p<0.001 both). Lesion dimension ≤10 mm was associated with lower AUC values. Lesion site didn't influence the diagnostic performance. Interobserver agreement was very good for STIR and DWI (k=0.887, p <0.001, and k=0.867, p <0.001).

DISCUSSION

UE-MRI has a good overall diagnostic performance in the detection of breast cancer and a very good specificity for both STIR and DWI sequences. We observed reduced diagnostic performance for lesions ≤10 mm in size. Lesion's site isn't associated with a significantly decreased diagnostic performance of UE-MRI. There's a good interobserver agreement for both sequences (STIR and DWI).

CONCLUSIONS

UE-MRI may be employed in patients with contraindication to gadolinium. It has considerable specificity and positive predictive value and good reproducibility.

The Value of Semi-Quantitative Analysis of 123I-FP-CIT SPECT in Evaluating Patients with Parkinson's Disease

(123)I-FP-CIT SPECT binding to striatal dopamine transporter (DAT) is markedly reduced in patients with Parkinson's disease (PD) and it may also help in identifyng pre-symptomatic nigrostriatal dysfunction in subjects at risk. This study used semi-quantitative analysis of 123I-FP-CIT SPECT to evaluate the possibility of a more extensive and earlier diagnosis of dopaminergic damage. We used qualitative visual assessment and semiquantitative measures of striatal DAT binding using (123)I-FP-CIT SPECT in 154 patients with suspected PD. A control group comprised 18 people age-matched to the PD group whose follow-up disclosed essential tremor. Abnormal striatal 123I-FP-CIT uptake was evident in 134 out of 154 patients (87%). Qualitative visual assessment showed striatal dopaminergic (123)I-FP-CIT uptake was significantly reduced in 60.4% (controlateral putamen to the symptoms), in 31.3% (caudate nucleus) and in 8.3% (ipsolateral basal ganglia to the symptoms). Semi-quantitative analysis showed the following results: 32.8%, 50.7% and 16.5% respectively. We compared these two assessments and their correlation with PD clinical progression. At 24 month follow-up, patients with greater dopaminergic damage at semiquantitative analysis showed a more severe motor disability. Our findings indicate that (123)I-FP-CIT SPECT with semiquantitative analysis can offer a more accurate characterization of the dopaminergic damage in patients with suspected Parkinson's disease.

Magnetic resonance angiography of the origins of the supraaortic arteries: comparison of single and double volume acquisition 3D time of flight

PURPOSE

The authors have optimized the technique of Magnetic Resonance Angiography (MR-angio) in the study of the origins of the supraaortic arteries.

METHODS

Twenty healthy volunteers, mean age 21.5, were studied with MR-angio of the origins of the supraaortic arteries; a 1 T superconductive magnet (Impact) with body coil was used. All the volunteers were studied using Time of flight (TOF), and two acquisition techniques: single volume FISP (fast imaging with steady-state precession) 3D TONE (titled optimized non-saturating excitation) and double volume FISP 3D TONE with 30% overlapping. The images were acquired on the axial plane following the positioning of three pre-saturation pulses.

RESULTS

Regarding the visualization of the different components of the origins of the supraaortic arteries, a statistical analysis was worked out using the Mann Whitney test (p < 0.05); there was no statistically significant difference between two techniques. Regarding the visualization of the various segments (origin, 1/3 proximal, 1/3 middle, 1/3 distal), although the double volume did on the one hand allow a better visualization of the more distal vascular components (statiscally significant difference), on the other it induced the presence of artefacts with decreased the quality of the image as a whole.

DISCUSSION

In our experience TOF 3D technique with TONE and single volume has well identified the origin of the vertebral arteries, while, in several cases, TOF 3D technique with TONE and double volume did not permit the visualization of the origin of the vertebral arteries due to the presence of the artefacts from overlapping.

CONCLUSION

From our experience we have established that the TOF 3D technique with TONE and single volume makes it possible to obtain MR-angio of a high diagnostic quality in a short time (10-15 mn).