Computed tomography of mediastinal lymph nodes in nonsmall cell lung cancer. A new approach based on the lymphatic pathway of tumor spread

Computed tomography was used to evaluate mediastinal lymph nodes in 97 patients with nonsmall cell lung cancer. All patients had thorough surgical-pathological determination of mediastinal node status. Twenty-three patients were found to have metastatic lymph nodes. The usual lymphatic pathways of tumor spread into the mediastinum were defined using the node mapping scheme suggested by the American Thoracic Society. We considered mediastinal nodes abnormal when the short axis of the largest mediastinal node in the lymphatic drainage territory of the cancer was greater than or equal to 10 mm and the difference between this node and the largest node in the other territories is greater than 5 mm. The sensitivity was 78%, the specificity 99%, the positive predictive value 95%, the negative predictive value 94%, and the accuracy 94%. Comparing our method to those that used the size criterion alone, the number of false positives was reduced.     

Spinal imaging: will MRI replace myelography?

A retrospective study on the value of magnetic resonance imaging (MRI) in replacing contrast studies of the lumbar spine has been undertaken. Studying pre- and postoperative conditions, the authors attempted to answer the question, Will MRI replace myelography? In this retrospective study, comparison is made in 20 patients between MRI and myelography and with 12 intra-operative findings. The overall impression was that MRI is equally sensitive as the invasive myelogram in diagnosing both protruded lumbar discs and postoperative fibrosis. The practical conclusion was an almost complete abandonment of myelography.     

Smoking--a major cause of polycythaemia.

The importance of smoking in the aetiology of polycythaemia has been assessed in a group of patients referred to a general haematology clinic. All patients with true and relative polycythaemia (excluding those with polycythaemia rubra vera) were studied. Of the 21 such patients evaluated, 14 were smokers and had raised carboxyhaemoglobin levels and had no other demonstrable cause for their polycythaemia. The commonest physiological abnormality in these patients was a raised red cell mass combined with a low plasma volume. Six of the 14 patients were able to reduce their smoking with subsequent improvement in their haematocrits. These results suggest that smoking is a major cause of polycythaemia in an unselected series of referrals to a general haematology clinic. The early identification of these patients may be useful in planning therapy.