Improved histopathological evaluation of gliomas using tissue fragments obtained by ultrasonic aspiration.

Ultrasonic aspirators are commonly used to resect brain tumors because they allow safe, rapid and accurate removal of dissected tissue. However, the tissue fragments removed by ultrasonic aspirators are used surprisingly little in daily diagnostics and in clinical research. A comparison between diagnoses made on the tissue fragments removed by the Sonocut ultrasonic aspirator and the tissue in conventional tumor biopsies was made. The correspondence between the amount of Sonocut tissue analyzed and the probability of making the most malignant diagnosis was analyzed statistically in order to limit the amount of tissue fragments, which need to be analyzed, and in order to save tissue for other purposes like molecular genetics and in vitro drug sensitivity assays. Thirty cases were included in the present study and consisted of astrocytomas, glioblastomas, oligodendrogliomas and ependymomas. The results showed that in 8 out of 30 cases only the Sonocut tissue fragments contained the tumor components that provided the most malignant diagnosis. In further 20 cases, the Sonocut tissue fragments and conventional tumor biopsies gave the same diagnoses. In the remaining 2 cases, the most malignant foci were included in the biopsy removed for peroperative frozen section investigation. When the slides with Sonocut tissue fragments were analyzed, the probability of making the most malignant diagnosis increased from 81.3% - 99.1%, when slides from 1 - 5 paraffin blocks were analyzed, respectively. When subgroups of small, medium and big tumors were analyzed, it was found that only 2 paraffin blocks from small tumors need to be prepared to reach 98.3% probability of making the most malignant diagnosis, whereas 5 paraffin blocks from big tumors need to be prepared to reach a 96.8% probability. In conclusion, the study shows that a limited amount of Sonocut ultrasonic tissue fragments improve the diagnostic evaluation of gliomas. These tissue fragments therefore must not be discarded. Only few paraffin blocks need to be prepared to reach close to 100% probability of making the most malignant diagnosis, reducing the amount of slides, which have to be analyzed and saving Sonocut tissue fragments for future use in molecular genetics and drug sensitivity assays.

Comparison of clinical judgment and diagnostic ultrasonography in the diagnosis of acute appendicitis: experience with a score-aided diagnosis.

OBJECTIVE: To evaluate the diagnostic accuracy of clinical judgment and diagnostic ultrasonography (US) used routinely and to create a scoring system to aid diagnosis. DESIGN: Prospective, double-blind study. SETTING: University hospital, Denmark. SUBJECTS: 222 Consecutive patients suspected of having acute appendicitis admitted between 0800 and midnight from June 1990 to June 1992. INTERVENTIONS: 148 Patients (67%) underwent appendicectomy and the remaining 74 patients were observed. 193 Patients (87%) had a diagnostic US examination. 21 Predictive variables were collected prospectively to create a scoring system. MAIN OUTCOME MEASURES: Results of surgical pathological findings, clinical outcome (observed group), diagnostic US, and values of diagnostic score. RESULTS: The decision to operate was made by a junior surgeon solely on the clinical examination, which yielded a diagnostic accuracy of 76%, specificity of 58%, and negative appendicectomy rate of 36%. 193 Patients underwent diagnostic US conducted by the radiologist on call of whom 123 were operated on, 78 for histologically proven appendicitis. US had a diagnostic accuracy of 72%, sensitivity of 49%, and specificity of 88%. Of the 21 predictive factors for acute appendicitis 11 were significant (p < 0.05): total white cell count (WCC) (>10 x 10[9]/1), migration of pain to the right lower quadrant, gradual onset of pain, increasing intensity of pain, pain aggravated by movement, pain aggravated by coughing, anorexia, vomiting, indirect tenderness (Rovsing's sign), muscle spasm, and sex. These 11 predictors were assigned an appropriate weight, based on the likelihood ratio, and used to create a scoring system. The score performed poorly if it was used to separate patients for observation and those for appendicectomy. However, if the score was used with two cut-off points resulting in three test zones (low, intermediate, and high risk of having acute appendicitis), some diagnostic benefit was seen for those patients within the zones of high and low probability. CONCLUSION: The clinical judgment of a junior surgeon was disappointing, and diagnostic aids are desirable to reduce the negative appendicectomy rate. Diagnostic US performed poorly as a routine procedure. Application of an up to date scoring system might be of some help to patients with a high or low probability of acute appendicitis, but any conclusion about its clinical application cannot be drawn from this study.