Stefan O.R. Pfleiderer

Ultrasound-guided, percutaneous cryotherapy of small (< or = 15 mm) breast cancers.

Rationale and Objective:The purpose of this study was to investigate the feasibility, efficacy, and safety of ultrasound-guided percutaneous cryotherapy of stage T1 breast cancers. Materials and Methods:Thirty patients with biopsy-confirmed breast cancers with tumor diameters of 15 mm or smaller (range, 5–15 mm; median, 12 mm) underwent cryotherapy. After local anesthesia, a 3-mm cryo probe was placed into the tumor under ultrasound guidance. All tumors were subjected to 2 freeze cycles with an interposing thawing cycle. The size of the iceballs, their distance to the skin, and the temperature at the tip of the probe were closely monitored during the procedure. The patients underwent surgery within 6 weeks and the specimens were evaluated histologically. Results:The median minimum temperature reached –146°C (range, −117°C to −167°C). In 5 of 29 patients, remnant ductal carcinoma in situ was detectable histologically after cryotherapy beyond the margin of the cryosite in the specimens after open surgery. In 24 patients, no viable tumor cells were found. No severe side effects occurred. In one patient, the cryo procedure was not performed completely because of technical problems. Discussion:Percutaneous cryotherapy is a feasible and safe procedure in minimally invasive therapy for small breast cancers. Residual ductal carcinoma in situ may be attributable to the beginning of a learning curve or by false-negative detection in preinterventional imaging. Magnetic resonance mammography might aid in treatment planning and for therapy monitoring to better define target tissue and to correlate the tumor margin with the iceball.

A manipulator system for 14-gauge large core breast biopsies inside a high-field whole-body MR scanner

To investigate a robotic manipulator system for MR‐guided breast biopsies inside a 1.5 T whole‐body magnet.

MRI-guided interventions of the breast

MRI has proven to be a very reliable diagnostic tool in the detection and differential diagnosis of breast lesions. Some lesions are, even in retrospect, not detectable in x‐ray or ultrasound images but MRI is able to detect lesions at a much smaller size than the average size of lesions depicted by x‐ray and ultrasound. The aim in the future is to develop combined procedures where imaging, biopsy, and interventional therapies are combined in a single outpatient procedure. As a step toward this goal different interventional procedures are useful that include interstitial laser therapy (ILT), radiofrequency ablation (RFA), high‐intensity focused ultrasound (HIFU), microwave ablation therapy, and cryotherapy. In this overview the main features and initial results of these procedures are described and discussed. J. Magn. Reson. Imaging 2008;27:347–355.

Are unnecessary follow-up procedures induced by computer-aided diagnosis (CAD) in mammography? Comparison of mammographic diagnosis with and without use of CAD

OBJECTIVE To evaluate the rate of unnecessary follow-up procedures recommended by radiologists using a CAD-system. MATERIALS AND METHODS 185 patients (740 images) were consecutively selected from three groups (36 histologically proven cancers = group 1; 49 histologically proven benign lesions = group 2 and 100 screening cases (4 years-follow up = group 3). Mammograms were evaluated by a CAD system (Second Look, CADx, Canada). Five blinded radiologists assessed the images without/with CAD outputs. Diagnostic decisions were ranked from surely benign to surely malignant according to BIRADS classification, follow-up procedures were recommended for each observed lesion (a, screening; b, short interval follow-up examination in 6 months; c, pathologic clarification). RESULTS CAD-system detected 32/36 cancers (88.9%) (FP-rate: 1.04 massmarks and 0.27 calcmarks/image). The following values were reached by all observers without/with CAD in the mean: Sensitivity 80.6/80.0%, specificity 83.2/86.4%, PPV 53.1/58.1%, and NPV 94.6/94.7%. Observers described a similar number of additional lesions without/with the use of CAD (325/326). Whereas the number of unnecessary short-time follow up recommendations increased in all case-subgroups with CAD: 40.8/42.9% (group 1), 35.6/38.1% (group 2), 44.7/46.8% (group 3), respectively, the number of recommended biopsies decreased in all subgroups: group 1: 34.7/27.1%; group 2: 47.4/41.5%, group 3: 33.3/22.0%, respectively. CONCLUSION In this rather small population additional usage of CAD led to a lower rate of unnecessary biopsies. The observed decrease of recommended unnecessary biopsies due to the usage of CAD in the screening group suggests a potential financial benefit by using CAD as diagnostic aid.

Magnetic resonance-guided large-core breast biopsy inside a 1.5-T magnetic resonance scanner using an automatic system: in vitro experiments and preliminary clinical experience in four patients.

Rationale and Objective:The aim of this study was to investigate the feasibility and the precision of magnetic resonance (MR)-guided large-core breast biopsies (LCBB) by using the second prototype of an automatic system (ROBITOM II), which is used to localize lesions while operating at the isocenter of a 1.5-T whole-body scanner. Methods and Materials:In comparison to the first prototype, ROBITOM II is equipped with a dedicated double breast coil and a high-speed trocar setting unit. In vitro experiments (n = 25) with grapefruit phantoms, which contained multiple vitamin E capsules (12 × 7 mm in size) as artificial lesions, were performed. Four patients with MR-detectable breast lesions underwent biopsy. A trocar was positioned in front of the lesion and inserted into the breast. Specimens were harvested with a coaxial technique by using a 14-G core needle biopsy gun. Results:In all 25 in vitro experiments, capsule material was detected in the specimen cylinder. In 4 patients, the coaxial needle was detected exactly at the expected position. Between 8 and 16 tissue cylinders were harvested. Histologic evaluation resulted in 1 invasive ductal carcinoma and 1 papilloma, which were confirmed after open surgery. One patient who had a proven breast cancer was biopsied for exclusion of multifocal disease. She showed fibrocystic changes, whereas open surgery revealed 3 small areas of ductal carcinoma in situ (DCIS). Another patient showed fibroadenoma after biopsy. This patient is in the follow-up period, which has lasted between 3 and 4 months up until now. Conclusions:In this pilot patient study, the feasibility of manipulator-assisted large-core breast biopsy inside a 1.5-T whole-body scanner was demonstrated by using ROBITOM II. The precision of the device was confirmed with in vitro experiments. Although these findings are preliminary and the follow-up period is rather short, they nevertheless represent a successful proof-of-principle of LCBB with ROBITOM II.

Changes in magnetic resonance mammography due to hormone replacement therapy

BackgroundThe aim of the present article is to investigate effects of hormone replacement therapy (HRT) on contrast medium enhancement patterns in postmenopausal patients during magnetic resonance mammography (MRM).Materials and methodsTwo hundred and fifteen patients receiving hormonal medication were divided into four groups: 150 patients with 1 MRM during HRT (group A), 13 patients with 2 MRMs under HRT (group B), 30 patients with 1 MRM during HRT and 1 MRM after HRT withdrawal (group C), and 22 women with 1 MRM after HRT withdrawal (group D). Dynamic MRM was performed at 1.5 Tesla. Signal intensity changes were characterized by five time curves: minimal enhancement (type I), weak continuous enhancement (type II), strong continuous enhancement (type III), and a steep initial slope followed by a plateau phenomenon (type IV) or a washout effect (type V).ResultsOf all 193 patients under HRT (group A + group B + group C), 60 patients (31.1%) showed curve type I, 88 patients (45.6%) showed type II and 45 patients (23.3%) showed type III. There were significant differences to 52 patients after HRT withdrawal (group C + group D) (P < 0.0001), with 42 patients (80.8%) for curve type I, 8 patients (15.4%) for type II, and 2 patients (3.8%) for type III. In both MRM sessions in group B, 69% of the patients showed identical curve types without significant differences (P = 0.375). In group C, 28 of 30 patients (93%) dropped to lower curve types with significant differences in curve types during and after HRT (P < 0.0001).ConclusionThe majority of patients receiving postmenopausal HRT showed bilateral symmetrical, continuous enhancement without evidence of a plateau phenomenon or a washout effect due to HRT in MRM. Hormonal effects could be proven and were reproducible and reversible.

ROBITOM II: robot for biopsy and therapy of the mamma

MR-mammography (MRM) reaches a high sensitivity in detecting breast carcinomas of 3 mm in size at least. In cooperation with the Institute of Diagnostic and Interventional Radiology of the Friedrich-Schiller University of Jena, a manipulator has been developed by the IMB, which combines the advantages of MRM imaging with a minimally invasive biopsy and a possible subsequent therapy. The experiences and results of tests with prototype ROBITOM I were brought into the following prototype ROBITOM II. For use of the therapy applicator (cryo), the guiding channel had to be scaled up and also an active breast coil was built. The well-known tissue drift while biopsy with needles is solved within the new prototype. ROBITOM II is designed according the medical electrical devices for clinical use under the terms of DIN EN 60601. The development work of the basic version ROBITOM II is completed, the approval according to the clinical trials may be expected during the next weeks.

Comparison of artifacts produced from carbon fiber and titanium alloy needles at 1.5 T MR imaging.

A novel coaxial carbon fiber‐based biopsy needle set was investigated in phantom experiments and compared with a commercially available, magnetic resonance (MR)‐compatible titanium alloy set using MR imaging at 1.5 T. Image artifacts observed with different MR sequences were assessed. It was found that the carbon fibers produced distinctly smaller image artifacts compared with the titanium needle. Depending on the type of MR sequence, the relative range of artifact size ratios between the carbon and titanium needles was between 0.7 (spin‐echo sequence) and 0.4 (gradient‐echo sequence) with the needles oriented perpendicular to the main magnetic field. Carbon fiber composites are promising materials for the design and construction of MR‐compatible instruments. J. Magn. Reson. Imaging 2000;11:69–74.

31P-MR spectroscopy in children and adolescents with a familial risk of schizophrenia.

Abstract. Based on a previous report [9] on alterations of membrane phosphorus metabolism in asymptomatic family members of schizophrenic patients, the aim of the present study was to extend and improve the evaluation and data processing of 31P spectroscopic data obtained from a larger study population by including an analysis of the broad spectral component (BC) of membrane phospholipids (PL). Eighteen children and siblings of patients with schizophrenia and a gender- and age-matched control group of 18 healthy subjects without familial schizophrenia were investigated with phosphorus magnetic resonance spectroscopy (31P-MRS) by using image selected in vivo spectroscopy (ISIS) in the dorsolateral prefrontal regions (DLPFR) of the brain. Spectral analysis was performed by using both the full and truncated FID to estimate metabolic peak ratios of different 31P metabolites and the intensity and linewidth of the broad component. A significantly higher PDE level (p<0.01) and increased linewidth of the PDE components were observed for the high-risk group compared with the control group (p=0.02). No significant differences were observed for PME as well as for other 31P-metabolites. No differences were observed between the left and right hemispheres for different normalised 31P-metabolic levels. Decreased intensities (p=0.03) and smaller linewidths (p=0.01) were obtained for the broad component in the high-risk group. Impairments of membrane metabolism that are typical for schizophrenic patients are partially observed in adolescent asymptomatic family members of schizophrenics, including increased levels of low molecular PDE compounds indicating increased membrane degradation processes, no changes for PME, and decreased intensities and linewidths of the BC indicating changes in the composition and fluidity of membrane phospholipids. Despite limitations to completely suppress fast-relaxing components by dismissing initial FID data points, the spectroscopic results indicate additional changes in the membrane metabolism of high-risk subjects beyond changes of synthesis and degradation.

Diagnosis of ductal carcinoma in situ using contrast-enhanced magnetic resonance mammography compared with conventional mammography

PURPOSE The objective of this study is to compare mammography with magnetic resonance mammography (MRM) in the diagnosis of histopathologically verified subtypes of ductal carcinoma in situ (DCIS). MATERIALS AND METHODS All patients with verified pure DCIS lesions (no signs of invasion or microinvasion) after surgery were identified between 2004 and 2006. Selection criteria were performed mammography and MRM at our institute prior to surgery resulting in a cohort of 33 patients (mean patient age, 60 years; mean lesion size, 15 mm). RESULTS Magnetic resonance mammography enabled identification of DCIS in 29 of 33 patients with histopathologically verified pure DCIS (7 G1, 13 G2, and 9 G3 subtypes), giving an overall sensitivity of 87.9% for this patient cohort. Four DCIS lesions (two G1 and two G2) up to 5 mm diameter or smaller were not detected by MRM. In mammography, 21 of the 33 patients revealed suspicious outcome (including all lesions not detected by MRM), demonstrating an overall sensitivity of 63.6%. The remaining 12 mammographically occult DCIS lesions (three G1 subtypes, four G2 subtypes, five G3 subtypes) were all identified in MRM. CONCLUSION Magnetic resonance mammography can diagnose mammographically visible and also occult DCIS lesions without microcalcifications. Only small DCIS foci with microcalcifications could additionally be verified by mammography supposing MRM as a diagnostic approach.