The effect of imaging modality on patient management in the evaluation of pulmonary thromboembolism.

A retrospective medical record review was performed to study the differences in clinical risk profiles and the relationships between test results versus management for suspected pulmonary thromboembolism (TE) in patients undergoing either radionuclide ventilation perfusion (V/Q) scans or pulmonary computed tomographic angiography (CTA), as the initial test. Data of 138 consecutive V/Q patients were compared with that of 149 consecutive CTA patients during equivalent 6-month intervals before and after the introduction of CTA. Information on risk factors, signs and symptoms, all diagnostic test results, and the relationships between the test results and ultimate physician management were collected and analyzed. V/Q results predicted physician management in all patients with high probability scans and 91% with normal to low probability scans. There were 35 patients with indeterminate V/Q scans--43% of these patients were managed without any other diagnostic test. CTA results predicted management in all patients with positive studies and 99% of patients with negative studies. In contrast to the V/Q cohort, only seven CTA studies were inconclusive--additional diagnostic tests determined management in all but one case. Compared with V/Q, CTA has fewer indeterminate results, is more directly reflective of management, and reduces the number of patients managed with inconclusive data.

Imaging of surgical paraphernalia: what belongs in the patient and what does not.

Many radiologists are not familiar with the names of various instruments, surgical sponges, and needles that may be seen on intraoperative and postoperative radiographs. These devices may be intentionally placed for localization or therapeutic intervention, discovered on radiographs obtained to evaluate incorrect sponge or needle counts, or incidentally encountered on postoperative radiographs. These paraphernalia are usually described in vague nonspecific terms in radiology reports. In this article, photographs and radiographs of several instruments commonly used for intraoperative localization or therapy are presented, as well as examples of sponges, needles, and other devices that should not be found on postoperative radiographs. Familiarity with their appearances will allow a more precise and knowledgeable description in radiology reports.

Major histocompatibility complex class I and class II antigen expression in diffuse large cell and large cell immunoblastic lymphomas. Absence of a correlation between antigen expression and clinical outcome.

The major histocompatibility complex (MHC) class I (HLA-A, B, C) and class II (HLA-DR) antigens are involved in cell-to-cell recognition and in regulating the immune response. Others have shown previously that MHC class I and class II antigens may be absent in a subset of malignant lymphomas, prompting the hypothesis that the absence of MHC antigen expression may be one of the mechanisms involved in the growth and dissemination of malignant lymphomas (by allowing a neoplasm to escape immune surveillance). To address this hypothesis, we analyzed MHC class I and class II (HLA-DR) antigen expression by diffuse large cell and large cell immunoblastic lymphomas in 88 and 117 patients, respectively, using frozen sections and the monoclonal antibodies W6/32 (HLA-A, B, C), anti-beta 2-microglobulin, and L203 (HLA-DR). Although there were no statistically significant clinical differences by MHC class II antigen expression, a small group of patients with MHC class I antigen-negative lymphomas were significantly younger (P = 0.03), less often had small neoplasms (P = 0.03), and were treated with doxorubicin-based chemotherapy more frequently (P = 0.04) than those with antigen-positive lymphomas. However, neither MHC class I nor class II antigen expression by the lymphomas consistently correlated with patient survival or freedom from relapse. This lack of correlation was true for all patients assessed, as well as for the subsets of patients with B-cell lymphomas, T-cell neoplasms, or those treated with doxorubicin-based chemotherapy. In accordance with previously published studies, stage, presence of B symptoms, and treatment with doxorubicin-based chemotherapy were of prognostic importance in univariate or multivariate analyses for survival or freedom from relapse. The findings may be considered evidence against the hypothesis that the absence of MHC class I or II antigen expression by malignant lymphomas plays a role in their tumorigenicity. However, we cannot completely exclude the possibility that the therapies used for this group of patients may have obscured any effect that MHC antigen expression exerts on prognosis.

Different cytotoxic and mutagenic responses induced by X-rays in two human lymphoblastoid cell lines derived from a single donor.

Two human lymphoblastoid cell lineages derived from the same parental line exhibit markedly different survival and mutational responses to X-irradiation, but not to chemical point mutagens. WI-L2-NS (ATCC CRL 8155) and TK6 (ATCC CRL 8015) both are derived from the original WI-L2 isolate described by Levy et al. (1968). Both lines are near diploid with stable and indistinguishable karyotypes (47, X, Y 13 +). However, differences in the extent of heterozygosity of chromosome 17 RFLP markers have been detected in these lines. Relative to TK6, WI-L2-NS and several cell lines subsequently derived from it exhibit enhanced survival after X-ray treatment. This is due partly to a more pronounced shoulder in the dose response curve for WI-L2-NS and partly to a higher D0 than is observed in TK6. X-ray-induced mutant frequencies also are markedly different. At the hprt locus, the overall magnitude of the response is similar in the two cell lines. However, in TK6, a linear equation appears to be the best fit to the data, as compared to a linear quadratic curve for WI-L2-NS. Induced mutant frequencies at the tk locus in heterozygotes derived from WI-L2-NS are 20-50-fold higher than those seen in TK6 and tk heterozygous derivatives of TK6. Analysis of the mutability of the two tk alleles in various tk heterozygotes of WI-L2-NS reveals a similar pattern to that described previously in heterozygotes derived from TK6; 3 times as many mutants were recovered from one tk allele than the other. A possible explanation for the higher survival and induced mutant frequencies seen in WI-L2-NS and its derivatives is the presence in these lines of an error prone repair system not functioning in TK6.