The unique sound production of the Death's-head hawkmoth (Acherontia atropos (Linnaeus, 1758)) revisited.

When disturbed, adults of the Death's-head hawkmoth (Lepidoptera, Sphingidae: Acherontia atropos) produce short squeaks by drawing in and deflating air into and out of the pharynx as a defence mechanism. We took a new look at Prell's hypothesis of a two-phase mechanism by providing new insights into the functional morphology behind the pharyngeal sound production of this species. First, we compared the head anatomy of A. atropos with another sphingid species, Manduca sexta, by using micro-computed tomography (CT) and 3D reconstruction methods. Despite differences in feeding behaviour and capability of sound production in the two species, the musculature in the head is surprisingly similar. However, A. atropos has a much shorter proboscis and a modified epipharynx with a distinct sclerotised lobe projecting into the opening of the pharynx. Second, we observed the sound production in vivo with X-ray videography, mammography CT and high-speed videography. Third, we analysed acoustic pressure over time and spectral frequency composition of six A. atropos specimens, both intact and with a removed proboscis. Single squeaks of A. atropos last for ca. 200 ms and consist of an inflation phase, a short pause and a deflation phase. The inflation phase is characterised by a burst of ca. 50 pulses with decreasing pulse frequency and a major frequency peak at ca. 8 kHz, followed by harmonics ranging up to more than 60 kHz. The deflation phase is characterised by a less clear acoustic pattern, a lower amplitude and more pronounced peaks in the same frequency range. The removal of the proboscis resulted in a significantly shortened squeak, a lower acoustic pressure level and a slightly more limited frequency spectrum. We hypothesise that the uptake of viscous honey facilitated the evolution of an efficient valve at the opening of the pharynx (i.e. a modified epipharynx), and that sound production could relatively easily have evolved based on this morphological pre-adaptation.

Ultrasound-guided breast biopsy using a 10-gauge self-contained vacuum-assisted device.

The purpose of this study was to evaluate the diagnostic value of a self-contained battery-driven vacuum-assisted breast biopsy (VABB) system for the sampling of breast masses under ultrasound guidance. Sixty-five patients with 70 lesions underwent percutaneous 10-gauge ultrasound-guided VABB using the coaxial technique. In 38 lesions, subsequent surgery and comparison of histology was performed. The remaining 32 cases were followed-up and defined as true negative after a cancer-free interval of 24 months. VABB revealed malignant histology in 28 (40%) cases. Twenty-four malignancies were confirmed after surgery. Four invasive cancers verified in VABB were not found during surgery because they were completely removed, as proved by a disease-free interval of 24 months. One cancer missed in ultrasound-guided VABB due to its small size was successfully diagnosed with stereotactic VABB and thus turned out to be false negative, resulting in an overall sensitivity of 96.6%. Forty-one patients were free of cancer during the follow-up period of at least 24 months. In conclusion, the self-contained VABB device is well suited for ultrasound-guided breast biopsies.

The adjacent vessel on dynamic contrast-enhanced breast MRI.

OBJECTIVE: The purpose of this study was to investigate whether an adjacent vessel leading to an enhancing lesion seen on subtraction images can help differentiate malignant from benign breast lesions and therefore increase the specificity of breast MRI. MATERIALS AND METHODS: The study included 132 histologically verified lesions (71 malignant lesions, 10 pure carcinoma in situ, and 51 benign lesions) enhancing on dynamic breast MRI before biopsy. The lesions were evaluated by three radiologists in a double-blinded manner. The presence of an adjacent vessel was supposed if at least two observers voted positively. RESULTS: Sixty-one (85.9%) of 71 malignant lesions, six (60%) of 10 carcinomas in situ, and 10 (19.6%) of 51 benign lesions were associated with an adjacent vessel, which differed significantly (p < 0.001) between benign and malignant lesions (the latter with and without including pure carcinoma in situ), leading to a positive predictive value of 85.9% (87% including pure carcinomas in situ), a negative predictive value of 80.4% (74.5% including pure carcinomas in situ), an accuracy of 83.2% (81.6% including pure carcinomas in situ), a sensitivity of 85.9% (82.7% including carcinomas in situ), and a specificity of 80.4% for this sign concerning malignancy. CONCLUSION: The presence of an adjacent vessel seen on subtraction images promises to be a good marker for malignancy and can therefore help increase the specificity of breast MRI.

Differentiation of phyllodes breast tumors from fibroadenomas on MRI.

OBJECTIVE: The purpose of our study was to evaluate the MRI appearance of phyllodes breast tumors and to differentiate them from fibroadenomas. MATERIALS AND METHODS: MR images were obtained on a 1.5-T imager. T1- and T2-weighted sequences and dynamic 2D fast-field echo T1-weighted sequences were performed. MR images of 23 patients with 24 phyllodes breast tumors (one malignant, 23 benign) were analyzed with respect to morphology and contrast enhancement. The tumors were compared with the MRI appearance of 81 fibroadenomas of 75 patients. RESULTS: Well-defined margins were seen in 87.5% of the phyllodes tumors and 70.4% of the fibroadenomas, and a round or lobulated shape in 100% and 90.1%, respectively. A heterogeneous internal structure was observed in 70.8% of phyllodes tumors and in 49.4% of fibroadenomas. Nonenhancing internal septations were found in 45.8% of phyllodes tumors and 27.2% of fibroadenomas. A significantly greater increase in signal was seen on T2-weighted images in the tissue surrounding phyllodes tumors (21%) compared with fibroadenomas (1.2%). Most of both lesions appeared with low signal intensity on T1- and T2-weighted images. After the administration of contrast material, 33.3% of phyllodes tumors and 22.2% of fibroadenomas showed a suspicious signal intensity-time course. CONCLUSION: Phyllodes breast tumors and other fibroadenomas cannot be precisely differentiated on breast MRI. Phyllodes tumors have benign morphologic features and contrast enhancement characteristics suggestive of malignancy in 33% of cases.

Potential MRI interpretation model: differentiation of benign from malignant breast masses.

OBJECTIVE: Our objective was to increase the accuracy of breast MRI using a semiquantitative analysis of typical MRI features and their diagnostic potential. The prevalence of recently reported MRI signs of breast lesions were analyzed and compared with other well-known signs. CONCLUSION: New MRI features, especially from T2-weighted images, are promising for more reliable and accurate interpretation of breast lesions. Prospective studies of these findings are required to define cut-off values and test clinical practicality.

Further signs in the evaluation of magnetic resonance mammography: a retrospective study.

PURPOSE: To increase accuracy and reliability of magnetic resonance breast imaging, a new evaluation method might be helpful. The recently suggested evaluation method (Fischer U, et al) resulted in a relevant number of equivocal cases (3 or 4 points). Additional morphologic and dynamic signs as an extension of this score were evaluated. METHOD AND MATERIALS: One hundred thirty-two histologically verified lesions were evaluated by 3 radiologists double-blinded using 2 evaluation methods: 1) method 1 (according to Fischer, et al): 2pt: initial signal increase >100%, washout, centripetal enhancement, 1pt: initial signal increase 50-100%, plateau phenomenon, centrifugal inhomogeneous enhancement, irregular borders, linear, stellar or dendritic structure; and 2) method 2 (according to Malich, et al): 3pt: hook sign (sign of pectoral invasion), 2pt: unifocal edema, blooming. 1pt: hypointensity in T2, lymph nodes >10 mm, skin thickening, adjacent vessels, a lesion's distorted inner architecture, disruption of the mamillary edge; -1pt: isointensity in T2, no edema, enhancing septations; -3pt: hyperintensity in T2, non enhancing septations. Method 1 judged a lesion to be malignant if 5 or more points were given and benign if 2 or less points were given, respectively. Method 2 (mean value of 3 radiologists) was tested in those cases in which a clear possible decision using method 1 was not sufficiently possible. RESULTS: Method 1 alone resulted in a negative predictive value of 96.8% and a positive predictive value of 90.8% (without carcinoma in situ), a sensitivity of 83.1%, a specificity of 58.8%, and revealed uncertain results (3 and 4 points) in 29 cases (out of 132; 22%). Adding the new scoring system in these 29 equivocal cases and an increase of 2 or more points by using method 2 is supposed to be a sign of malignancy; findings suggest a sensitivity of 90.9% and a specificity of 60% if an increase of maximum 1 is observed in benign lesions. In conclusion, our results show that Göttingen score alone has a sensitivity of 83.1%, a specificity of 58.8%; the second evaluation method reveals a sensitivity of 90.9% and a specificity of 60% in equivocal cases of Göttingen score. Göttingen score then reaches in all cases and second, adding the second evaluation method in equivocal cases, a sensitivity of 97% and a specificity of 76.5%. CONCLUSION: The application of a second evaluation method in those cases remaining unclear in Göttingen score can lead to a decrease of uncertainty and a higher sensitivity and specificity of diagnosis in MR mammography. In this study, Göttingen score reaches a sensitivity of 83.1% and a specificity of 58.8%, increasing to a sensitivity of 97% and a specificity of 76.5% when being extended by a second evaluation method in unclear cases.

Subtraction of in-phase and opposed-phase images in dynamic MR mammography.

PURPOSE: To develop and to evaluate an advanced image acquisition and analysis method for collecting T(1)-weighted dynamic 3D MR mammography data sets by using a combined in-phase (IP) and opposed-phase (OP) imaging procedure. MATERIALS AND METHODS: 3D MR mammography data sets were acquired by applying an interleaved gradient-echo OP and IP imaging sequence during administration of contrast agent. A phantom data set, two volunteer breast data sets, and six patient breast data sets were recorded. Subtraction of dynamic in-phase magnitude images was performed for clinical assessment. In addition, the magnitude subtraction (SIPOP) as well as the complex subtraction (cSIPOP) of the IP and OP magnitude and phase images were considered. RESULTS: The detection of small lesions, lesion boundaries, and tumor offshoots in fatty tissue was improved by the subtraction of IP and OP images without the risk of signal cancellation due to partial volume effects. CONCLUSION: Dynamic MR mammography acquisition of IP and OP images in combination with appropriate data processing yields important supplementary information that can support routinely applied diagnostics of breast lesions that are fully embedded in fatty tissue by only marginally increasing acquisition time.

Changes in magnetic resonance mammography due to hormone replacement therapy.

BACKGROUND: The 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 METHODS: Two 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). RESULTS: Of 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). CONCLUSION: The 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.

[Interventional MR-mammography: manipulator-assisted large core biopsy and interstitial laser therapy of tumors of the female breast]]. / Interventionelle MR-Mammographie: Manipulatorgestützte Biopsie und interstitielle Lasertherapie von Tumoren der weiblichen Brust.

The present study investigated the clinical application of magnetic resonance (MR)-guided breast interventions, such as manipulator-assisted large core breast biopsy (LCBB) inside a 1.5 T whole-body magnet and MR-guided interstitial laser therapy (ILT). Sixteen patients underwent LCBB and 1 additional patient underwent 4 sessions of ILT of a recurrent undifferentiated lymph node metastasis in the axilla using a Nd-YAG laser (1064 nm). Temperature changes of the tumor tissue during ILT were monitored using phase images of a gradient echo sequence (GRE) (TR/TE/FA = 25/12/30). In 5 patients the biopsy findings were histopathologically confirmed after open surgery. In 3 patients, the biopsy missed one tubular and one ductal carcinoma; one invasive carcinoma was underestimated. Eight patients with benign findings are still in the follow-up period. The heating zone during ILT was well delineated on subtracted phase images. No severe adverse events were observed with LCBB or ILT. MR-guided breast biopsies are feasible with the manipulator system inside a whole-body 1.5 Tesla MR scanner. GRE information is suitable for therapy monitoring during ILT within the tumor. Further studies are necessary to evaluate the accuracy of the manipulator system and the efficacy of ILT in the treatment of breast lesions.

Dedicated double breast coil for magnetic resonance mammography imaging, biopsy, and preoperative localization.

RATIONALE AND OBJECTIVES: The aim of this study was to compare the performance of a dedicated double breast coil for MR imaging and intervention with a standard diagnostic double breast coil. MATERIALS AND METHODS: Signal-to-noise ratios (SNRs) were determined for both coils by using a water phantom. Fourteen patients were examined, 11 underwent preoperative hookwire localization, two were biopsied, and one received diagnostic imaging. Breast images were acquired in three patients with both coils and were visually compared. Harvested specimen from the biopsies and surgeries following hookwire localization were histopathologically evaluated. RESULTS: SNR was superior with the interventional coil in the posterior (axillary) part of the imaging volume and inferior in the anterior part compared with the standard coil. Anatomic MR breast images were of similar diagnostic quality. For the two biopsy procedures the trocar was correctly placed in front of the suspicious lesion. Hookwires were correctly located inside the lesion in nine patients and in contact with the lesion in one patient. In one patient a 2 mm distance between the lesion and the wire was observed. CONCLUSIONS: Diagnostic imaging followed by subsequent MR-guided intervention is possible within a single session by using the dedicated interventional coil. The correct final position of the hookwires demonstrates the precision of the MR guided localization procedure.

MRI of the pelvic ring joints postpartum: normal and pathological findings.

PURPOSE: To assess the joints of the pelvic ring postpartum and to discern normal postpartum findings and pathologic lesions using MRI. MATERIALS AND METHODS: MR images were obtained in six women with severe pelvic ring pain after delivery, in 13 women after uncomplicated vaginal delivery, and in 11 healthy, nulliparous non-pregnant volunteers. Distances of the pubic gap, signal intensities of the pubic cartilage, and signal changes of the pelvic ring bones were determined and evaluated. RESULTS: Both postpartum groups had significantly larger distances of the interpubic gap compared to the nulliparous group (P = 0.0002). The mean signal intensity of cartilage of the symphysis pubis was significantly different on the T1-weighted and T2-weighted MR images in postpartum women compared to nulliparous women (P = 0.001), indicating a higher water content of the pubic cartilage. 13 of all 19 postpartum women had bruises of parasymphyseal pubic bones. One pubic symphysis rupture and one sacral stress fracture were detected in two symptomatic women. CONCLUSION: MR imaging is a useful adjunct to clinical examination to identify patients with lesions of the pelvic ring postpartum. MRI of the pelvic ring of asymptomatic postpartum women can demonstrate signal changes of the pubic cartilage and small bruises of the pubic bones.