Biomedical subjects

K Kinkel

Publications and source records attributed to K Kinkel.

26 records · Page 2Linked to original sources

PubMed1998

Technical aspects of breast magnetic resonance imaging.

The appropriate role for magnetic resonance imaging (MRI) as an adjunct technique to mammography in the detection, diagnosis, staging, and therapy management of breast cancer has been the subject of much current research. The clinical application determines the choice of imaging technique. Time restraints due to the rapid kinetics of contrast enhancement require that trade-offs be made between spatial and temporal resolution, with a resulting effect on sensitivity and specificity. This article discusses some general requirements and recommendations for breast MRI techniques, including dedicated radiofrequency coils, pulse sequence specifications and image quality considerations, fat-suppression techniques, methods of contrast administration, and image postprocessing and interpretation.

Artifacts↗

PubMed1997

Differentiation between recurrent tumor and benign conditions after treatment of gynecologic pelvic carcinoma: value of dynamic contrast-enhanced subtraction MR imaging.

PURPOSE: To compare dynamic contrast material-enhanced subtraction and T2-weighted spin-echo (SE) magnetic resonance (MR) imaging in the differentiation of fibrosis from tumor recurrence during the follow-up of treated gynecologic pelvic malignancy. MATERIALS AND METHODS: Thirty-four patients (aged 24-82 years) with 18 benign and 35 malignant lesions confirmed by means of surgery (n = 18), biopsy (n = 25), or 18-month follow-up examination (n = 10) underwent dynamic contrast-enhanced subtraction and T2-weighted SE MR imaging. Contrast material enhancement of an abnormal pelvic structure within the first 90 seconds on dynamic contrast-enhanced subtraction images or high signal intensity on T2-weighted SE images was considered indicative of malignancy. RESULTS: The sensitivity, specificity, accuracy, and positive and negative predictive values were 91%, 67%, 83%, 86%, and 86%, respectively, for dynamic contrast-enhanced subtraction imaging and 91%, 22%, 68%, 70%, and 57%, respectively, for T2-weighted SE imaging. More lesions were correctly classified with dynamic contrast-enhanced subtraction imaging than with T2-weighted SE imaging (P < .01). CONCLUSION: Dynamic contrast-enhanced subtraction imaging is more accurate than T2-weighted SE imaging for differentiating fibrosis from tumor recurrence during the follow-up of treated gynecologic pelvic malignancy. However, use of both sequences is recommended.

Adult↗

PubMed1996

MR imaging during intracavitary brachytherapy of vaginal and cervical cancer: preliminary results.

Intracavitary brachytherapy is an effective treatment for gynecologic cancers. Twelve magnetic resonance (MR) imaging studies were performed during intracavitary brachytherapy (10 initial studies and two during repeat brachytherapy) in 10 patients with clear cell adenocarcinoma (n = 9) or epithelioma (n = 1). Fifty percent of the vaginal lesions did not demonstrate high signal intensity on T2-weighted images. Individually tailored molded applicators allowed easy detection of abnormal vaginal parietal thickening on T1-weighted images: Results in seven cases were concordant with results of clinical examination, and there were no false-negative results. MR imaging was useful in controlling the relationships between the tumor and the applicator and facilitated treatment planning, since the radiation dose to the tumor volume and adjacent critical organs could be calculated accurately. Limitations of MR imaging were underestimation of superficial vaginal tumors and the inability to differentiate between tumor and inflammation after recent surgery or repeat intracavitary brachytherapy. MR imaging during intracavitary brachytherapy appears to be a useful adjunct to clinical examination.

Adenocarcinoma, Clear Cell↗

PubMed1996

Dynamic contrast-enhanced subtraction versus T2-weighted spin-echo MR imaging in the follow-up of colorectal neoplasm: a prospective study of 41 patients.

PURPOSE: To compare dynamic contrast-enhanced subtraction (DCES) and T2-weighted spin-echo (SE) magnetic resonance (MR) imaging in the differentiation of fibrosis from recurrence during the follow-up of treated colorectal neoplasms. MATERIALS AND METHODS: Forty-one patients with 39 malignant and 16 benign lesions confirmed by means of surgery (n = 23), biopsy (n = 24), or 12-month follow-up examination (n = 8) underwent DCES MR imaging and T2-weighted SE MR imaging. Enhancement of an abnormal pelvic structure within the first 90 seconds on DCES images or high signal intensity on T2-weighted SE images was considered indicative of malignancy. RESULTS: Sensitivity, specificity, and positive and negative predictive values were, respectively, 97%, 81%, 93%, and 100% for DCES MR imaging and 77%, 56%, 81%, and 56% for T2-weighted MR imaging. The number of correctly classified lesions was significantly higher with DCES imaging compared with T2-weighted imaging (P < or = .006). CONCLUSION: DCES imaging is more accurate than T2-weighted SE imaging for differentiating fibrosis from recurrence during the follow-up of treated colorectal neoplasms.

Colon↗

PubMed1996

[Ultrasound-guided biopsies for breast nodules: value of automatic biopsy needle].

Within 18 month, 83 solid breast nodules were biopsied with a long throw biopsy gun with 18 gauge needle (Monopty, Bard Urological, Covington) and a 13 Mhz real time AU 530 (Easote Biomedica, Italy) for the ultrasound guidance. The biopsy procedure was well tolerated with no serious complications, and with no insufficient material. US guided biopsy detected 9 cancers, 47 specific benign lesions (39 fibroadenomas, 1 lipofibroadenoma, 4 sclerosing adenoses, 1 fibromatosis, 1 cyst, 1 lymphadenopathy) and 27 non specific benign fibrocystic dystrophy. In 14 out of the 15 nodules surgically removed, the histological diagnoses were identical. In the one remaining case a fibroadenomas was assessed. In the 36 other cases no evolution occurred. US guided core biopsy with automatic device is probably a very useful approach of uncertain pathological diagnoses in mastology.

Adolescent↗

PubMed1994

Focal areas of increased opacity in ductal carcinoma in situ of the comedo type: mammographic-pathologic correlation.

PURPOSE: To determine a histopathologic explanation for focal areas of increased opacity on mammograms of ductal carcinoma in situ of the comedo type (comedocarcinoma). MATERIALS AND METHODS: From January 1991 to January 1993, mammograms from 36 patients with comedocarcinomas were reviewed. Each mammogram was screened for microcalcifications and/or any focal area of increased opacity. The presence or absence of infiltrating components was confirmed at pathologic examination, with particular emphasis placed on the search for any stromal reaction. RESULTS: The clinical examination revealed a palpable tumor in five patients (14%) and a bloody discharge from the nipple in two (5%). Isolated clusters of microcalcifications were seen at mammography in 24 patients (67%). Nine patients (25%) had clusters associated with focal areas of increased opacity; three patients (8%) had no microcalcifications. Histologic analysis demonstrated an intense, periductal, inflammatory reaction in all 12 patients with focal areas of increased opacity. CONCLUSION: Focal areas of increased opacity are not always indicative of an infiltrating component and may merely represent intense stromal reaction.

Adult↗

PubMedDate not supplied

MR imaging: breast cancer staging and screening.

This review describes the current knowledge and challenges of breast cancer staging and screening with MRI of the breast. Assessment of local disease extent, including tumor size, multicentricity, and chest wall invasion, can be obtained more accurately with MRI than with mammography. Moreover, international experts have established standardized reporting of MRI staging results, taking into account tumor size measurements and the number of breast quadrants involved. Results from MRI assessment of the axilla and skin are promising, but need further refinement. Preliminary results of the use of breast MRI in patients at high risk for breast cancer demonstrated a superiority of breast MRI over the combined use of mammography and high-frequency ultrasound. The role of MRI in this subset of patients may be confirmed by ongoing larger multicenter trials. Strict protocol conditions are mandatory to maintain a high standard of quality. Confirming the nature of "MRI-only" lesions with MRI-guided biopsy systems will allow changes in treatment planning. More accurate tumor diagnosis and tumor volume evaluation may allow minimally invasive treatment strategies.

Breast Neoplasms↗

PubMedDate not supplied

Pitfalls in staging uterine neoplasm with imaging: a review.

This review analyzes current pitfalls in pretreatment staging of endometrial and cervical carcinoma with magnetic resonance imaging (MRI) based on a critical review of the literature. Technical, patient, and tumor-related characteristics were analyzed to improve further staging of uterine neoplasm with MRI. For endometrial carcinoma staging, contrast-enhanced dynamic imaging appears essential to avoid false-positive findings for deep myometrial invasion by better delineating tumor from normal myometrium. However, leiomyomas, adenomyosis, and grade 3 tumors provide difficulties in staging for pathologists and radiologists. Slice orientation perpendicular to the long axis of the cervical channel might improve false-negative findings for deep stromal invasion on T2-weighted images in endometrial and cervical cancer. Contrast-enhanced sequences do not improve diagnosis of parametrial or vaginal invasion in cervical cancer. Assessment of lymph node invasion by any imaging modality has limited sensitivity in detecting lymph node metastasis smaller than 5 mm. Knowledge of diagnostic criteria is critical to avoid false-negative findings for bladder wall invasion. Higher spatial resolution with dedicated multichannel pelvic phase array coils, smaller fields of view and section thickness, and careful comparison of T2-weighted and contrast-enhanced sequences are strategies that might avoid misinterpretation of pelvic MRI in staging uterine neoplasm.

Aged↗