Use of a smaller coaxial stabilizing needle produces a substantially decreased risk of pneumothorax with comparable diagnostic accuracy, sensitivity, and specificity for histopathologic diagnosis of pulmonary nodules.

To assess which specific morphologic features, enhancement patterns, or pharmacokinetic parameters on breast Magnetic Resonance Imaging (MRI) could predict a false-negative outcome of Proton MR Spectroscopy ( 1 H MRS) exam in patients with invasive breast cancer. Sixteen patients with invasive ductal carcinoma of the breast were prospec-tively included and underwent both, contrast-enhanced breast MRI and 1 H MRS examination of the breast. The MR images were reviewed and the lesions morphologic features, enhancement patterns and pharmacokinetic parameters (k21-value) were scored according to the ACR BI-RADS-MRI lexicon criteria. For the in vivo MRS studies, each spectrum was evaluated for the presence of choline based on consensus reading. Breast MRI and 1 H MRS data were compared to histopathologic findings. In vivo 1 H MRS detected a choline peak in 14/16 (88%) cancers. A false-negative 1 H MRS study occurred in 2/16 (14%) cancer patients. K21 values differed between both groups: the 14 choline positive cancers had k21 values ranging from 0.01 to 0.20/second (mean 0.083/second), whereas the two choline-negative cancers showed k21 values of 0.03 and 0.05/second, respectively (mean 0.040/second). Also enhancement kinetics did differ between both groups; typically both cancers that were choline-negative showed a late phase plateau (100%), whereas this was only shown in 51/4 (36%) of the choline positive cases. There was no difference between both groups with regard to morphologic features on MRI. This study showed that false-negative 1 H MRS examinations do occur in breast cancer patients, and that the presence of a choline peak on 1 H MRS as malignancy marker is related to the k21 value of the invasive tumor being imaged.Keywords breast cancer; k21-value; magnetic resonance imaging; proton MR spectroscopy Contrast-enhanced breast magnetic resonance imaging (MRI) detects breast cancer with almost 100% sensitivity, and plays an increasingly important role in breast cancer detection and staging (1). However, the specificity of breast MRI is rather variable, ranging from 37% to 97%, resulting in moderate false-positive rates and unnecessary biopsies (2-5).To optimize specificity in breast MRI combined high spatial-resolution imaging and rapid dynamic imaging for concurrent evaluation of detailed lesion morphology characteristics and

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