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Biomedical subjects

B G Steinbach

Publications and source records attributed to B G Steinbach.

12 recordsLinked to original sources
PubMed1997

Optimal technique factors for magnification mammography.

RATIONALE AND OBJECTIVES: Use of small focal spots with low x-ray tube currents may result in very long exposure times and thus result in motion blur in magnification mammography. The authors investigated the reduction in exposure time with increasing x-ray tube kVp and the corresponding decrease in perceived visibility of low-contrast objects in phantom images. METHODS: Exposure times required to radiograph an RMI 156 phantom in a magnification geometry were measured as a function of x-ray tube kVp when operated under automatic exposure control. Magnification images of the RMI 156 phantom were obtained at x-ray tube voltages ranging from 28 to 34 kVp. Five radiology residents ranked the visibility of two borderline fibers and six borderline microcalcification specks using a 5-point scale ranging from excellent to barely visible. RESULTS: Between 28 and 34 kVp, the density of the RMI phantom images was nearly constant with a mean value of 1.32 +/- 0.04. Increasing the x-ray tube voltage from 28 kVp to 34 kVp reduced the exposure time from 1.27 seconds to 0.66 seconds. Image quality at 30 and 32 kVp was not significantly worse than that achieved at 28 kVp. Increasing the x-ray tube voltage to 34 kVp, however, resulted in a statistically significant (P < 0.001) deterioration in the relative visibility of fibers and microcalcification specks. CONCLUSIONS: Magnification mammography performed at 32 kVp will decrease exposure times significantly and result in a microcalcification and fiber visibility that is similar to that achieved at 28 kVp.

Humans↗
PubMed1996

Use of a modified polysaccharide gel in developing a realistic breast phantom for MRI.

A polysaccharide material, TX-151, has been used together with water, NaCl, and Al powder to create a tissue equivalent gel to make a realistic, inexpensive, conveniently moldable, temporally stable tissue equivalent MRI phantom. Various phantom compositions were studied for variations in gelling time and relaxation times. Gd-DTPA added as a T1 (and T2) modifier and aluminum powder added to decrease T2 permitted phantoms to be made with a range of relaxation times comparable to human tissues. We have used this polysaccharide gel to create breast phantoms for testing breast coils and evaluating different MRI imaging sequences available for diagnosis. The breast phantoms consisted of a layer of Crisco, a good model for adipose tissue, surrounding the TX-151 gel. Some of these phantoms were created with a silicone implant encapsulated in the gel to simulate an augmented breast. More sophisticated phantoms can easily be developed by additions of other materials to this polysaccharide gel.

Female↗
PubMed1993

Breast implants, common complications, and concurrent breast disease.

Recent concern regarding breast implants has emphasized the special imaging needs of the approximately 2 million American women who currently have prosthetic breast implants, including silicone gel, silicone gel with a textured silicone coating, saline, biocompatible gel, polyurethane-coated, double-lumen, and tissue expanders. Both palpable and nonpalpable breast lesions can occur in patients with implants, and these lesions must be evaluated in the same manner as in patients without implants, which presents a challenge for the mammographer. Not only is the breast tissue of a patient with implants more difficult to image, but the patient may have complications from the implants. The major complications of their use involve hematoma in the early postoperative period, infection, capsule contracture, rupture, and silicone granulomas. Familiarity with the more common types of implants, the possible complications of their use, and concurrent breast disease may help improve diagnosis in these patients.

Adult↗
PubMed1993

Bilateral breast masses in a man.

Other than gynecomastia, bilateral breast masses in a male patient is an unusual occurrence. We present a case of fat necrosis presenting in a male veteran as bilateral palpable breast masses.

Aged↗
PubMed1992

Metastatic cervical carcinoma to the breast.

Metastatic disease to the breast is often an unexpected diagnosis in a female who presents with a breast mass. The most important factor suggesting the appropriate diagnosis is a history of cancer. Correlation of mammographic and ultrasonographic findings may also raise the possibility of a metastatic mass. A well-defined, noncalcified dense mass on film-screen mammography, which also shows low-level homogeneous echoes without posterior acoustic enhancement, suggests the diagnosis. It is important that the diagnosis be made by fine needle aspiration or excisional biopsy so as to expedite appropriate therapy.

Biopsy↗
PubMed1992

Phantom evaluation of imaging modalities for silicone breast implants.

RATIONALE AND OBJECTIVES: Recent concern regarding possible adverse effects from silicone breast implants has increased the role of radiologists in assessing augmented breasts. The authors compare the commonly available imaging modalities in evaluating the intact silicone implant as well as free silicone in the adjacent tissue. METHODS: A contrast resolution phantom and breast of veal phantom were tested. Fat was used as a reference material. The phantoms were imaged with xeromammography, film-screen mammography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). Proton MRI spectroscopy also was performed on fat, silicone, water, and water/gelatin samples. The consensus of two radiologists determined whether free silicone was present. RESULTS: CT and MRI provided the best images of the implant and the free silicone. Several features of MRI were useful: spin-density scans and the fast low-angle shot (FLASH) and fast imaging with steady-state precision (FISP) techniques provided excellent resolution, a consistent chemical shift artifact appeared around the silicone, and frequency selective pre-saturation techniques resulted in marked suppression of the silicone. CONCLUSION: Additional testing in a more realistic setting, breast coil design, and improvement of various MRI techniques, particularly the frequency selective pre-saturation techniques, all appear promising in evaluating breast implants, the presence of free silicone, and the adjacent tissues.

Breast↗
PubMed1991

Noninvasive assessment of implant capsules.

The assessment of implant capsular contracture has been imprecise and vulnerable to observer bias. Attempts to measure capsules with instruments that measure implant deformability are influenced by surrounding breast tissue, subcutaneous fat, and skin. Xeromammography, B-mode ultrasound, and CT were employed in an effort to provide a noninvasive and accurate method of capsule assessment. Through two study phases, implants were placed bilaterally in a total of 21 rabbits. At 4 months, animals underwent radiologic assessment and were then sacrificed for direct implant capsule measurements. Mammographic measurements, more than ultrasound-derived measurements, strongly correlated with laboratory measures of capsular dimensions and deformability. Cross-table lateral mammographic views were more informative than traditional views, providing measures of diameter and height that both strongly correlated with laboratory measurements. CT is theoretically the most accurate method to assess contracture, but it is impractical because of expense and time requirements. The results indicate that radiologic assessment, in particular by xeromammography, of implant capsules is accurate, practical, and noninvasive. Mammography strongly correlates with laboratory measures of implant capsular contracture and therefore could be used in the clinical setting to assess capsular contracture.

Animals↗
PubMed1988

Retractable-barb needle for breast lesion localization: use in 60 cases.

A needle system with a retractable barb was developed for localization of nonpalpable breast lesions. The system can be repositioned without major adjustments and strongly anchors to breast tissue, eliminating failure due to dislodgment or transection of the localizing wire. Its use may necessitate fewer confirmatory radiographs, resulting in decreased radiation exposure. In addition, the needle can be retracted during surgery, to ease extraction of the specimen.

Biopsy, Needle↗
PubMedDate not supplied

Mammography: breast implants--types, complications, and adjacent breast pathology.

Approximately 1.5 million women in the United States currently have breast implants. The majority were placed for cosmetic augmentation, but 20% were placed for reconstruction after the loss or deformity of a breast. The augmented breast is a challenge to the mammographer. Many of the palpable and mammographically detected abnormalities in these patients are related to the implant itself. Since, however, there is breast tissue present with cosmetic augmentation, the full range of fibrocystic and neoplastic conditions that can affect the breast may be seen. The presence of the implant makes imaging the breast more difficult because the implant obscures the nearby breast tissue. This paper reviews the history and evolution of various breast prostheses. The surgical approaches to placement of implants and complications associated with their use will be discussed. Examples of concomitant pathologies and a review of imaging strategies will be given.

Breast Diseases↗