In vivo breast tissue backscatter measurements with 7.5- and 10-MHz transducers.

Measurements of the ultrasound (US) backscatter coefficient (BSC) of fibroglandular and fatty breast tissues in vivo from 5.25 through 13 MHz, using the reference phantom method, are presented. Radiofrequency echo data were collected at a series of locations in the left breasts of 16 adults, age 46 to 84, and in a custom-built phantom calibrated for backscatter and attenuation. Matched regions of interest (ROIs) were then selected in these images, from which the backscatter coefficient and the backscatter frequency dependence were ratiometrically estimated, after compensation for attenuation. The mean results in fibroglandular tissues were 78.9 x 10(-3)/cm, sr at 7.2 MHz (n(ROI) = 43, n = 13) and 146 x 10(-3)/cm, sr at 10.3 MHz (n(ROI) = 19, n = 10) with frequency dependencies of f(2.28) and f(3.25). The corresponding results in subcutaneous fat were 2.59 x 10(-3)/cm, sr at 7.2 MHz (n(ROI) = 56, n = 16) and 7.08 x 10(-3)/cm, sr at 10.3 MHz (n(ROI) = 57, n = 16) with frequency dependencies of f(3.49) and f(3.43). These findings are discussed and compared to similar measurements in the literature.

Breast tumour imaging using incomplete circular orbit pinhole SPET: a phantom study.

Improvements in 99Tcm-sestamibi breast lesion visualization using single photon emission tomography (SPET) may help define the clinical role of this technique alongside X-ray mammography in the diagnosis and management of breast cancer. Pinhole SPET offers the advantages of high resolution and sensitivity when compared to conventional parallel-beam collimation for sources located near the pinhole aperture. In this work, the potential of incomplete (180 degrees) circular orbit (ICO) SPET with pinhole collimation is investigated as a means to visualize small (6.4 and 9.6 mm diameter) spherical simulated tumours, at clinical count densities and tumour-to-background ratios, in a breast phantom. ICO pinhole SPET is compared to complete circular orbit (CCO) pinhole SPET for reference, and planar breast imaging (scintimammography) using parallel-beam and pinhole collimators. A prototype box-shaped pinhole collimator with a 4 mm diameter circular aperture was used to acquire projections of an 890 ml breast phantom both in isolation and mounted on a cylinder filled with a mixture of 99Tcm-pertechnetate and water. A heart phantom containing 99Tcm activity in the myocardium was placed in the cylinder. Simulated tumours containing 99Tcm were placed in the breast phantom and scanned at clinically relevant count densities and scan times with tumour-to-normal tissue concentration ratios of 5.0:1 (9.6 mm sphere) and 7.7:1 (6.4 mm sphere). Phantom data were reconstructed using pinhole filtered backprojection (FBP) and maximum likelihood-expectation maximization (ML-EM). The tumours were not visualized with scintimammography, in which lesion contrast and signal-to-noise were estimated from region of interest analysis to be < 2% and 0.01, respectively. Average (over lesion size and scan time) contrast and signal-to-noise in the ICO (CCO) SPET images were 33% and 1.72 (34% and 1.3), respectively. These values indicate that ICO pinhole SPET has the potential to improve visualization of small (< 10 mm) breast tumours when compared with scintimammography, which may be beneficial for the early classification of cancers of the breast.

The evolving role of sonography in evaluating solid breast masses.

Many investigators have attempted to use ultrasound imaging to differentiate benign from malignant solid breast masses. Studies have evaluated several generations of gray-scale imaging, Doppler, color Doppler, and power Doppler imaging, and several unconventional ultrasound techniques. Although various individual studies have shown promise, ultrasound criteria for avoiding biopsy of solid lesions have not been widely adopted. Considerable observer variability also remains an important obstacle. This article reviews the results, strengths, and weaknesses of some of the key studies addressing this issue. Fundamental criteria for a successful ultrasound model are also specified.

Splenic vein aneurysm: MR appearance--a case report.

A presumed pancreatic head mass by non-contrast CT examination, was proven to be a splenic vein aneurysm by enhanced CT, MRI, sonography and arteriography. Dangerous percutaneous aspiration was avoided.

Tissue harmonic imaging sonography of breast lesions: improved margin analysis, conspicuity, and image quality compared to conventional ultrasound.

The purpose of this preference study is to determine if tissue harmonic imaging (THI) is preferred over conventional sonography for imaging breast masses. A prospective evaluation of 73 identical image pairs (one obtained with conventional sonography, one with THI sonography) was performed, examining 25 cysts, 36 solid masses, and 12 indeterminate lesions. Each image was evaluated for lesion contrast, margins, and overall image quality using a graduated score. Statistical analysis was performed using a modified t test. For cystic and solid lesions, THI was preferred for lesion conspicuity, margin, and overall quality (P<.001). For indeterminate lesions, THI was significantly preferred for lesion conspicuity and overall quality (P<.05), but the preference for margins was not significant. Overall, THI of breast lesions was significantly preferred for lesion contrast and margin evaluation compared to conventional sonography. This modality deserves further evaluation and may improve detection and evaluation of breast lesions.

Stereotactic biopsy of noncalcified breast lesions: utility of vacuum-assisted technique compared to multipass automated gun technique.

The purpose of this study was to evaluate the stereotactic 14-gauge, vacuum-assisted biopsy technique in diagnosing noncalcified breast lesions. Stereotactic biopsy of 116 noncalcified breast lesions was performed with either 14-gauge, vacuum-assisted technique or multipass, automated large-core technique. The number of core samples and time required for each biopsy were compared. Outcome for each technique was compared based on recommendations after the mammographic-histologic review process. Results from surgical excision and mammographic follow-up were reviewed. The vacuum-assisted technique obtained more tissue cores per lesion than the automated gun technique, showed marginal decrease in number of repeat biopsies for discordant results, and required fewer short-term follow-up mammograms, although the difference did not achieve statistical significance. The vacuum-assisted technique can be used successfully to sample noncalcified breast masses, with marginal improvement over the automated gun technique.

Intra-aortic counterpulsation balloon pumps: CT appearance.

Intra-aortic counterpulsation balloon pumps (ICBP) used in the setting of cardiogenic shock or high risk cardiac surgery, have been identified on chest films in the inflated state during diastole (1). We report characteristic computed tomography (CT) findings of an inflated ICBP, discuss its radiographically identified complications, and suggest that the presence of this device should be excluded before suspecting other etiologies for intra-aortic gas.

Degenerative disease of the lumbar spine. Role of CT-myelography in the MR era.

One hundred patients with degenerative disease of the lumbar spine on whom both magnetic resonance (MR) and computed tomography (CT)-myelography were performed were reviewed. In one-third of the cases, the CT-myelogram provided additional useful information. This included definition of the extent of large disc herniations, demonstration of focal neural compression by small herniations, and clarifying abnormalities of the facets, including synovial cysts. These results should help to refine the indications for CT-myelography, which continues to be requested extensively.

Periprosthetic mycobacterial infection. CT and mammographic findings.

Organisms of the Mycobacterium fortuitum complex are an uncommon but important cause of periprosthetic infection following augmentation mammoplasty or other breast surgery. This etiological agent must be considered in the particular case of periprosthetic infection, because special handling of the fluid is crucial to enhance recovery of the organism. We describe the computed tomography (CT) and mammographic findings in such an abscess with respect to the clinical context and subsequent management. To our knowledge, CT findings associated with any periprosthetic breast infection have not been described.

Metastatic lesions arising in a Riedel's lobe. Findings from a sulfur colloid liver-spleen scan.

Clinically significant lesions originating within a Riedel's lobe are extremely rare. Characteristic findings from a Tc-99m SC liver-spleen scan of metastatic breast carcinoma arising in a Riedel's lobe are described.

Imaging-guided core biopsies in the breast.

Screening mammography programs have contributed to an overall decline in breast cancer mortality. The screening process, however, also results in detection and biopsy of many nonpalpable lesions that eventually prove to be benign, contributing to the burden of costs to our health care system. Percutaneous imaging-guided core biopsy has proven to be a safe and accurate technique for obtaining a histologic diagnosis in most patients who have screening-detected lesions; it is done at lower cost with lower resultant morbidity to the patient compared with traditional surgical excisional biopsy. I review the indications, techniques, method of correlating the histology with mammographic findings, and accreditation requirements for imaging-guided core biopsies of the breast done under mammographic (ie, stereotactic) or sonographic guidance.

Seromas in the breast: imaging findings.

Breast seromas are tumor-like collections of serosanguineous fluid in breast tissue that occur following excisional biopsy, lumpectomy, mastectomy, and plastic surgery procedures such as augmentation, prosthesis explantation, breast reduction, and breast reconstruction. Mammographically seromas are water-density masses located at the surgical site. They exhibit features characteristic of fluid collections on sonographic evaluation. This article reviews the spectrum of imaging findings associated with breast seromas.

Extended field-of-view two-dimensional ultrasonography of the breast: improvement in lesion documentation.

The purpose of this study was to evaluate the use of extended field-of-view two-dimensional ultrasonographic imaging for improvement in overall breast lesion documentation. Sonographic images of 59 patients with breast lesions or silicone implants were evaluated by three radiologists retrospectively to compare traditional static linear array images alone with images obtained with the addition of an extended field of view to determine if documentation of lesions was improved. The addition of extended field-of-view imaging improved lesion conspicuity by 21% over traditional images. It provided overall improvement in lesion documentation by including a reference point (nipple) or by more completely imaging large masses in 79% and implants in 69%. The larger field of view of this technique is promising as an adjunct to traditional sonography for breast lesion documentation.

Fat necrosis in the breast: sonographic features.

PURPOSE: To evaluate the ultrasonographic (US) features and evolution of fat necrosis in the breast. MATERIALS AND METHODS: The US features of 31 breast masses in 23 patients were reviewed. Fat necrosis was diagnosed on the basis of histologic (n = 20) and initial or follow-up (minimum follow-up, 15 months) mammographic (n = 11) findings. RESULTS: Sonograms demonstrated discrete masses in all but one patient. On the basis of the predominant US finding, masses were categorized as solid (n = 15), complex with mural nodules (n = 7), complex with echogenic bands (n = 4), anechoic with posterior acoustic enhancement (n = 2), anechoic with shadowing (n = 2), or no mass visible (n = 1). Distortion of the normal parenchymal architecture was seen in 21 masses. In four six masses, 1-26-month follow-up sonograms showed evolution of the US appearance. One solid mass remained solid appearing. Complex masses tended to evolve: Three became more solid appearing, and one became more cystic. No mass enlarged; two remained stable, and four decreased in size. CONCLUSION: A spectrum of US findings is associated with fat necrosis. If fat necrosis is suspected and mammographic findings are suspicious, knowledge of the US appearance and evolution of these patterns may enable imaging follow-up of these lesions rather than needless biopsy.

Focal fibrosis: a common breast lesion diagnosed at imaging-guided core biopsy.

OBJECTIVE: Focal fibrosis is a benign breast lesion commonly diagnosed by imaging-guided core biopsy. The goal of this study is to determine the frequency of focal fibrosis diagnosed at core biopsy and to describe its imaging features. MATERIALS AND METHODS: A consecutive series of 894 imaging-guided breast core biopsies were reviewed, and all cases of focal fibrosis were selected. The imaging features of each lesion were characterized. All lesions had been reviewed during radiologic-histologic review sessions to assess for accurate needle positioning and concordant results. Follow-up imaging and histologic data were reviewed to document lesion stability. RESULTS: Focal fibrosis was diagnosed in 80 (8.9%) of 894 imaging-guided core biopsies: 20 (8.7%) of 229 sonographically guided biopsies and 60 (9.0%) of 665 mammographically guided biopsies. Of 75 mammographically visible lesions, 39 (52%) were masses, 29 (39%) were densities, and seven (9.3%) were clusters of calcifications. Thirty-five hypoechoic lesions were visualized on sonography: 29 (80%) were oval, and six (17%) were irregularly shaped. Six (21%) of the 28 oval masses showed posterior enhancement, four (14%) posterior shadowing, and 19 (68%) neither feature. Fifty-two (65%) of 80 patients with focal fibrosis had routine imaging follow-up; all had stable findings (mean follow-up period, 27 months). No false-negative cases were identified. CONCLUSION: Focal fibrosis most commonly appears as an enlarging solid mass or developing density on mammography or as an oval mass on sonography. Our data suggest that focal fibrosis accounts for 9% of lesions that undergo imaging-guided core biopsy and that the diagnosis can be accurately reached using imaging-guided biopsy.

Seromas in residual fibrous capsules after explantation: mammographic and sonographic appearances.

PURPOSE: To evaluate the mammographic and sonographic findings associated with seromas that develop in residual fibrous capsules after explantation of breast prostheses. MATERIALS AND METHODS: Preoperative and postoperative mammograms were reviewed in 86 patients (mean age, 51 years; age range, 24-71 years) who had undergone surgical explantation of breast prostheses. Six seromas were found in four patients 46-68 years of age. Imaging findings were correlated with surgical and laboratory results for three seromas. A presumptive diagnosis was made of the other three lesions. RESULTS: Mammograms demonstrated all seromas as large, elliptic, water-opacity masses, some with well-circumscribed and some with irregular borders. Sonograms showed thin, compressible masses, two of which were flat and anechoic and one of which was hypoechoic. Three patients' images were initially misinterpreted, leading to excision of two seromas and aspiration of one. Seromas were not identified in patients whose implants were removed by means of complete capsulectomy. CONCLUSION: Radiologists must be aware of the imaging findings associated with seromas and of a patient's surgical history to avoid biopsy of benign lesions.

Mesenrhombencephalitis: MR findings in nine patients.

OBJECTIVE: Mesenrhombencephalitis is a serious form of brainstem inflammation predominantly involving the deep and vital portions of the brain, that is, the mesencephalon (midbrain) and rhombencephalon (pons, medulla). Mesenrhombencephalitis is difficult to diagnose on the basis of clinical and laboratory findings alone, and access to this portion of the brain for surgical biopsy carries high morbidity. We describe the MR appearance of mesenrhombencephalitis and correlate the imaging findings with clinical information. MATERIALS AND METHODS: Unenhanced and contrast-enhanced MR images of nine patients with mesenrhombencephalitis were reviewed retrospectively and correlated with clinical, laboratory, and pathologic data. The patients were categorized according to the cause of the disease: three had herpes simplex, one had Listeria monocytogenes, and five had mesenrhombencephalitis of undetermined cause. The three patients with clinical and MR evidence of herpes simplex mesenrhombencephalitis (one confirmed by brain biopsy) were comatose at presentation, with cranial nerve abnormalities in two and seizures in one. One patient with L. monocytogenes (established by blood culture) had cranial nerve palsies, fever, and pain in the ear. Five additional patients had headache (three), fever (three), nausea and vomiting (four), cranial nerve palsies (three), coma (two), and hyporeflexia (one) or hyperreflexia (four). Brain biopsy performed in two patients revealed chronic inflammation of unspecified cause; in one, it was compatible with viral encephalitis. RESULTS: MR images in three patients with herpes simplex mesenrhombencephalitis showed T2 signal hyperintensity in the midbrain (two), pons (one), medulla (one), and temporal lobes (three). Parenchymal foci of hemorrhage (methemoglobin, one patient) and leptomeningeal enhancement (one patient) were identified in the temporal lobes. T2-weighted MR images in one patient with L. monocytogenes showed signal hyperintensity in the brainstem, vermis, midbrain, and internal capsules. On T1-weighted images, low signal was present in these areas, which enhanced with paramagnetic contrast agents. In the remaining five patients, T2-weighted MR images showed patchy signal hyperintensity in the pons, medulla, and thalamus in three each and in the midbrain and temporal lobes in one each. T1-weighted MR images showed normal findings (two) or signal hypointensity in the thalamus and pons in one patient each. Areas of leptomeningeal and parenchymal enhancement were identified in one patient each. Brainstem swelling was seen in three patients, one of whom had petechial hemorrhage in the pons and hydrocephalus. CONCLUSION: Mesenrhombencephalitis is a serious illness that is diagnosed by a combination of imaging, clinical, laboratory, and pathologic studies. MR imaging may be crucial to the early diagnosis of this illness, and radiologists must be familiar with this uncommon entity and its MR findings in order to make timely diagnoses and facilitate treatment.

Papillary carcinoma of the breast: imaging findings.

Papillary carcinoma is a rare malignant tumor of the breast for which the survival rate is better than for most breast carcinomas. Histologically, invasive and in situ forms occur; the in situ form can extend throughout a ductal system (intraductal) or can be confined within a cystic structure (intracystic). Invasive papillary carcinoma can spread from either of the in situ forms but spreads more commonly from the intracystic type. Many reports in the literature have failed to differentiate invasive from in situ papillary carcinomas; similarly, the different mammographic patterns of the two in situ forms of these lesions have not been delineated clearly. Our review of 16 new cases of papillary carcinoma showed a frequent correlation between the histologic types and the mammographic appearance. The intraductal in situ form usually was characterized by clustered microcalcifications. The intracystic in situ type was associated with well-circumscribed masses on mammograms; these masses often were complex on sonograms. The purpose of this essay is to illustrate the mammographic and sonographic features of the histologic varieties of papillary carcinoma. Color Doppler sonograms and MR images of intracystic and invasive tumors also are included.

Silicone gel breast implant rupture, extracapsular silicone, and health status in a population of women.

OBJECTIVE: To assess whether breast implant rupture or extracapsular silicone are associated with selected symptoms of self-reported physician-diagnosed connective tissue disease (CTD). METHODS: Women with silicone gel breast implants responded to a questionnaire that included questions on health status, satisfaction with implants, symptoms of CTD, and physician-diagnosed disease. These women then had magnetic resonance imaging (MRI) of their breasts to determine the status of the implants with respect to rupture and extracapsular silicone. RESULTS: Women with breast implant rupture diagnosed by MRI were no more likely to report a diagnosis of selected CTD than those with intact implants or those with implants of indeterminate status. Women with extracapsular silicone (silicone gel outside of the fibrous scar that forms around breast implants) were more likely to report having fibromyalgia (FM, p = 0.004) or other CTD, which included dermatomyositis, polymyositis, Hashimoto's thyroiditis, mixed CTD, pulmonary fibrosis, eosinophilic fasciitis, and polymyalgia (p = 0.008) than other women in the study. The association with FM remained statistically significant when adjusted for multiple comparisons (7 diagnoses) and implant age, implant location, or implant manufacturer (p < 0.05 in all cases), but became of borderline statistical significance when adjusted for multiple comparisons and self-perceived health status (p = 0.094) or self-perceived rupture status (p = 0.051). The association with other CTD remained statistically significant when adjusted for multiple comparisons and implant location or implant manufacturer, but became borderline or insignificant when adjusted for multiple comparisons and for implant age (p = 0.051), self-perceived health status (p = 0.434), or self-perceived rupture status (p = 0.145). Logistic regression was used to compute odds ratios of self-reported diagnoses comparing women with and without extracapsular silicone. The odds ratios were 2.8 (95% CI 1.2 to 6.3) for FM, and 2.6 (95% CI 0.8 to 8.5) for other CTD after adjustment for implant age, implant location, implant manufacturer, implant type, self-perceived health, self-perceived rupture status, and site of surgery practice. CONCLUSION: These data suggest an association between extracapsular silicone from ruptured silicone breast implants and FM. If this association persists in other studies, women with silicone gel breast implants should be informed of the potential risk of developing fibromyalgia if their breast implants rupture and the silicone gel escapes the fibrous scar capsule.

The detection of breast microcalcifications with medical ultrasound.

Microcalcifications are small crystals of calcium apatites which form in human tissue through a number of mechanisms. The size, morphology, and distribution of microcalcifications are important indicators in the mammographic screening for and diagnosis of various carcinomas in the breast. Although x-ray mammography is currently the only accepted method for detecting microcalcifications, its efficacy in this regard can be reduced in the presence of dense parenchyma. Current ultrasound scanners do not reliably detect microcalcifications in the size range of clinical interest. The results of theoretical, simulation, and experimental studies focused on the improvement of the ultrasonic visualization of microcalcifications are presented. Methods for estimating the changes in microcalcification detection performance which result from changes in aperture geometry or the presence of an aberrator are presented. An analysis of the relative efficacy of spatial compounding and synthetic receive aperture geometries in the detection of microcalcifications is described. The impact of log compression of the detected image on visualization is discussed. Registered high resolution ultrasound and digital spot mammography images of microcalcifications in excised breast carcinoma tissue and results from the imaging of suspected microcalcifications in vivo are presented.