The uterine cavity appears on sonograms as a linear echo, which is usually visible during early pregnancy and remains straight until the eighth to ninth week of gestation. The early gestational sac is not enveloped by two layers of decidua, as suggested by descriptions of the double decidual sac sign; the sac (or echogenic area of early implantation) is actually located within a markedly thickened decidua on one side of the uterine cavity. The combination of these two sonographic characteristics is called the "intradecidual sign." An early implantation of 25 days gestational age can be detected by the presence of the intradecidual sign, which is sooner than a gestational sac can be seen. The implantation site can also be located by means of the intradecidual sign. In a study of 36 patients with early intrauterine pregnancy and five with ectopic pregnancy, the intradecidual sign was more sensitive (91.7% vs. 63.9%) and specific (100% vs. 60%) than the double decidual sac sign in the detection of early intrauterine pregnancy.

This study evaluates the mammographic findings in 352 patients, aged 30-85 years, who underwent spot localization and biopsy for evaluation of nonpalpable breast abnormalities. Malignancy was found at biopsy in 114 cases. The mammographic appearance (specifically, whether grouped microcalcifications, mass, or both were present) was correlated with patient age and histologic findings (specifically, whether the pathologic changes were infiltrating or noninfiltrating in nature). The prevalence of malignant conditions increased directly with age. The presence of grouped microcalcifications as the sole indicator of malignancy was seen in 100% (seven of seven) of the patients in the 30-39-year age group, 64% (18 of 28) in the 40-49-year age group, 37% (11 of 30) in the 50-59-year age group, 30% (seven of 23) in the 60-69-year age group, and 23% (six of 26) in the 70-85-year age group. Of the 49 tumors that were manifested solely as microcalcifications, 34 (69%) were noninfiltrating. The finding of grouped microcalcifications should be aggressively investigated, since it may indicate noninfiltrating carcinoma in an early stage, when the potential for cure is greatest.

Plain radiography and magnetic resonance (MR) imaging were used to assess the extent of transphyseal involvement in 15 consecutive patients with long bone osteosarcoma and nonfused epiphyses. The findings were correlated with those from surgical and microscopic pathologic examinations. There were no cases of false-positive findings with either MR imaging or plain radiography. Conventional radiography accurately helped predict transphyseal spread in only nine of 15 cases (60%). Spread to the epiphysis was present in 12 of the 15 cases (80%) and was accurately predicted with MR imaging in all 12 cases. This finding contradicts the common misconception that the physis acts as a "barrier" to tumor spread.

A comparative study using computed tomography and conventional posteroanterior radiography was performed on 27 patients with mesothelioma and 13 patients with advanced asbestosis. The major pathologic features of both asbestosis and mesothelioma were well demonstrated by both modalities; computed tomography demonstrated the findings more frequently and in greater detail. No distinguishing features could be established based on configuration and size of the lesion. Many pleural plaques associated with advanced asbestosis were large and irregular and resembled those associated with mesothelioma. However, nodular involvement of the pleural fissures, pleural effusion, and ipsilateral volume loss with a fixed mediastinum were features predominating in mesothelioma. Growth determination of the plaques associated with asbestosis may be of minimal value since such plaques also undergo growth due to active inflammatory changes.

Mammograms of 220 patients who underwent spot localization for removal of nonpalpable breast lesions were reviewed for accuracy of interpretation. Results of subsequent biopsy indicated malignancy in 77 cases. The interpretations of mammograms obtained before biopsy were incorrect in 71 cases (27 false-negative and 44 false-positive studies). Among the false-negative cases, 70% of the abnormalities were determined histologically to be noninfiltrative cancers. An aggressive screening program with preoperative localization and biopsy is needed in questionable cases, since mammographic signs of early or nonpalpable malignancy are often subtle and nonspecific.