Roberta Sarnelli

Evaluation of frequency dependence of backscatter coefficient in normal and atherosclerotic aortic walls

For five groups of aortic specimens (normals and with different degrees of atherosclerosis) the ultrasonic backscatter coefficient was measured as a function of frequency in the range 4-15 MHz. The results of the study are related to two classes of structure, connective and fatty tissue (whose relative amount in the arterial wall is related to the different stages of atherosclerosis), as the main determinants of the scattering from aorta. The structure of connective tissue in the aorta produces a power law frequency dependence of the backscatter coefficient typical of small scale structures (Ka much less than 1). Fatty tissue introduces a frequency dependence of the backscatter coefficient typical of structures of intermediate scale (Ka approximately equal to 1). Biochemical composition and structure of normal and atherosclerotic aorta therefore, specifically affect the employed acoustical parameter.

Ganglioglioma of the spinal cord

SummaryA case of ganglioglioma or neuroastrocytoma of the spinal cord in a 78-year-old man is reported. Diagnosis was based on the histological identification of the neoplastic cells and on the study of the architecture of the tumour. The presence of cellular anaplasia, sometimes of marked degree, and of small nests of infiltration suggested an initial malignant behaviour regarding both cellular types. A survey of the five reported cases of spinal ganglioglioma is presented.

Frequency-dependent attenuation in breast tissue characterization

The aim of this study is to establish whether an index derived from the slope of the frequency-dependent ultrasonic attenuation can provide quantitative information on normal and pathological breast tissue. Ultrasonic measurements were performed by using pulsed transmitted ultrasound in the frequency range 2-8 MHz. Thirty-three specimens were selected for their probable pathologic classification, by macroscopic observation, before ultrasonic study, and subsequently histologically classified. Ultrasonic results suggest the possibility that the examined specimens fall into four groups: (1) fat, fibroadenoma, giant fibroadenoma, infiltrating ductal carcinoma, medullary carcinoma; (2) infiltrating lobular carcinoma, tubular carcinoma, scirrhous carcinoma; (3) fibrosis; (4) fibrofatty tissue, fibrocystic disease. Correlative morphological studies indicate that the employed index can classify breast tissues on the basis of their cellular and fibrous composition and the inhomogeneity of their structure.

Evaluation of the attenuation coefficients in normal and pathological breast tissue

The present paper reports on measurements of frequency-dependent attenuation in normal and pathological breast tissue. Measurements were performed by using pulsed transmitted ultrasound. Five groups of breast specimens including fatty tissue, fibrofatty parenchyma and fibrosis, malignant tumours with and without productive fibrosis (infiltrating ductal carcinoma scirrhous type and medullary carcinoma, respectively) have been studied. The results of the attenuation measurements indicate that the attenuation coefficient is lower for tissues with large predominance of cells (fatty tissue, medullary carcinoma) and increases with collagen fibre content (infiltrating ductal carcinoma scrirrhous type, fibrosis, fibrofatty). A comparative nonlinear (best fitting) and linear analysis of the attenuation curves shows that it does not matter whether one uses a linear or nonlinear equation to describe the attenuation curves.

ORIENTATION AND FREQUENCY DEPENDENCE OF BACKSCATTER COEFFICIENT IN NORMAL AND PATHOLOGICAL BREAST TISSUES

The backscatter coefficient was measured on five groups of normal and pathological breast specimens: (1) as a function of frequency (in the range 4-14 MHz) and (2) at a single fixed frequency (10 MHz), as a function of the angle of incidence between the beam and the specimen (approximately 60 degrees). The results of the study are discussed in relation to the content of cells and collagen fibers in breast tissues. The absolute value of backscatter coefficient is larger in tissues with a prevalence of collagenous fibers in comparison to tissues with only cells. In fibrofatty tissue, the inhomogeneity of the specimens is probably responsible for the highest backscatter value. The power law frequency dependence of the backscatter coefficient is of a diffractive nature in tissues characterized by only cells; in tissues with a strong prevalence of collagenous fibers, the power law frequency dependence increases. Periodicities in the angular patterns have been quantified by the autocorrelation functions for each group of specimens. The results of the study suggest a means for assessing tissue structure in normal and pathological breast tissue.

Early Pathologic Changes in Experimental and Human Breast Cancer: Facts and Commentsa

All morphologic structures or pathophysiologic changes in the mammary glandular tree develop as a result of the hormonal stimuli that the gland receives. In this respect the breast represents the most typical example in the body of a dynamic structure. In fact, this end organ of the endocrine system converts the hormonal stimuli into morphologic structures, thus almost continuously changing its size, boundaries, and gross and histologic features. This paper deals with the earliest pathologic changes that may be observed in experimental and in human breast cancer, with particular emphasis on the biologic background and progression of these changes. However, only a few points and problems in the biology and pathology of breast carcinogenesis will be raised and commented upon in order to stimulate fruitful speculation and discussion.

Subgross physiopathology of the breast associated with clinical cancer.

Fifty human breasts removed for cancer by radical mastectomy were submitted to subgross analysis of the glandular tree as a whole, stained thin sections (2 mm) under a dissection microscope, followed by histologic study of the lesions found. The glandular tree was more often atrophic (70%) than hyperplastic (30%). The frequencies of physiopathologic changes were as follows: ductal papilloma (4%), ductal hyperplasia (6%), fibroadenoma (16%), sclerosing adenosis (24%), cysts (28%), apocrine cysts (18%), cystic ducts (40%), blind terminal ducts (60%), atrophic lobules (88%), sclerotic lobules (34%), hyperplastic lobules (28 %), cystic lobules (52%), persistent lobules in otherwise atrophic breasts (30%), lobules with apocrine metaplasia (30%), atypical lobules with proliferative changes (38 %), and independent foci of microscopic cancer (20%). The data indicate: 1) a frequent lack of correlation between ovarian function (menstrual cycles, menopause) and type of mammary glandular tree (hyperplastic, atrophic); 2) a rarity of ductal lesions compared with the frequency of lobular lesions; 3) a ubiquitous distribution of the lesions either near or far from clinical cancer; 4) a significant association of atypical lobules with lobular sclerosis (p < 0.001) and apocrine metaplasia (p < 0.05). The frequency and ubiquity of lobular changes suggest further investigation among them to search for suitable candidates as preneoplastic or predictive lesions.

Attenuation measurements in atherosclerotic tissues: Problems with phase-cancellation artefacts

The study was designed to establish whether changes in arterial wall structure due to atherosclerosis may be reflected in the increase of ultrasonic attenuation. Accordingly, fresh aortic wall specimens were analysed by an attenuation technique and pathologically classified into three groups: normal, fibrofatty and calcific. Analysis was performed by using a single broadband transducer acting as transmitter and receiver of the echo produced by a specular reflector positioned behind the specimen under study. Two indices were derived from the transfer function H(f) of the specimen: the slope of the best-fit straight line to In |H(f)| and the absolute value of In |H(f)| at 9MHz. The index based on the slope of In |H(f)| is able to distinguish normal wall from atherosclerotic lesions. The absolute value of In |H(f)| is able to differentiate normal, fibrofatty and calcific groups. However, such an index is strongly influenced by specular reflections at water/specimen interfaces. Acquisition of ultrasonic echoes was improved with the use of a small-diameter transducer, which is presumed to reduce distortion in the transfer function due to phase-cancellation effects. According to a statistical test based on the evaluation of the goodness of the straight-line fit to In |H(f)|, the results of the two sets of measurements were compared. The importance of a small-diameter transducer for the further reduction of phase-cancellation artefacts was assessed.

Cancerous versus noncancerous breasts: a comparative morphological analysis of the entire glandular tree of the breast

Cancerous and clinically normal autopsy obtained breasts were collected in order to compare the physiopathological profile of both types of glandular tree. Each breast was visualized by whole thin sections and observed under a stereomicroscope with removal of the more interesting changes for histology. The comparison was made between 67 atrophic cancerous breasts and 88 atrophic control breasts. The results were as follows: 25% of the cancerous breasts versus 47% of control breasts showed no changes, atypical lobules, microfoci of “in situ” and/or infiltrating cancer were present in 46% of cancerous breasts and in 16% of control breasts, showing a significant correlation with clinical cancer. All other types of functional and proliferative changes, variously associated each other, were found in 29% of cancerous and in 37% of control breasts. Our morphological data agree completely with the statements in follow-up studies carried out on benign breast biopsies. The significant differences in the physiopathological profile of the glandular tree between “normal” and cancerous breasts, confirms that some changes are causally related to clinical cancer.

Fatal peripheral airway cystic disease in a young woman

Diffuse cystic transformation of both lungs was rapidly fatal in a 33-year-old woman. This disorder, a rare congenital condition in infants, has apparently not been described in adulthood.