OBJECTIVE: Spiral volumetric computed tomography(spiral CT) has the advantage of direct imaging of intravascular thrombus or its relevant vascular abnormalities, but controversy exists about the value of spiral CT in the diagnosis of pulmonary embolism in the different levels of pulmonary artery. METHODS: The authors prospectively evaluated the diagnostic efficacy of spiral CT for pulmonary embolism in 20 patients (M:F=13:7, 57+/-10.4yrs) who were suspected to have pulmonary embolism from clinical symptoms and/or scintigraphic findings. Both spiral CT and pulmonary angiography were performed in these patients with the interval being 28+/-14.1 hours. The diagnostic efficacy of spiral CT was evaluated in the patients and also in the pulmonary arteries found to have emboli on pulmonary angiogram. RESULTS: Pulmonary embolism was diagnosed in 8 patients and excluded in 12 patients by pulmonary angiography. Spiral CT showed positive findings of pulmonary embolism in 7 of the 8 patients with pulmonary embolism, and was negative in 11 of the 12 patients without pulmonary embolism. The overall diagnostic efficacy of spiral CT for pulmonary embolism was: sensitivity 87%(7/8), specificity 92%(11/ 12), positive predictive value 87%(7/8), negative predictive value 92%(11/12), and accuracy 90%(18/20). For pulmonary embolism at lobar or greater pulmonary arteries, the diagnostic efficacy of spiral CT was: sensitivity 100%(15/15), specificity 98%(201/205), positive predictive value 79%(15/19), negative predictive value 100%(201/201), and accuracy 90% (216/220). For segmental or smaller arteries, how- ever, the diagnostic efficacy was: sensitivity 71%(15/ 21), specificity 98%(549/559), positive predictive value 60% (15/25), negative predictive value 99%(549/555), and accuracy 97%(554/580). CONCLUSION: Spiral CT can be a useful noninvasive method for the diagnosis of pulmonary embolism, and it may replace pulmonary angiography at the level of central pulmonary artery.
Angiography ; Arteries ; Diagnosis* ; Diuretics ; Heart Failure ; Humans ; Magnesium Deficiency ; Prospective Studies ; Pulmonary Artery ; Pulmonary Embolism* ; Sensitivity and Specificity ; Thrombosis ; Tomography, Spiral Computed*

Vitamin K2 is widely used for the treatment of osteoporosis in Japan. To understand the effects of vitamin K2 on bone mass and bone metabolism, we reviewed its effects on the development of osteopenia in rats, which characterizes models of osteoporosis. Vitamin K2 was found to attenuate the increase in bone resorption and/or maintain bone formation, reduce bone loss, protect against the loss of trabecular bone mass and its connectivity, and prevent the decrease in strength of the long bone in ovariectomized rats. However, combined treatment of bisphosphonates and vitamin K2 had an additive effect in preventing the deterioration of the trabecular bone architecture in ovariectomized rats, while the combined treatment of raloxifene and vitamin K2 improved the bone strength of the femoral neck. The use of vitamin K2 alone suppressed the increase in trabecular bone turnover and endocortical bone resorption, which attenuated the development of cancellous and cortical osteopenia in orchidectomized rats. In addition, vitamin K2 inhibited the decrease in bone formation in prednisolone-treated rats, thereby preventing cancellous and cortical osteopenia. In sciatic neurectomized rats, vitamin K2 suppressed endocortical bone resorption and stimulated bone formation, delaying the reduction of the trabecular thickness and retarding the development of cortical osteopenia. Vitamin K2 also prevented the acceleration of bone resorption and the reduction in bone formation in tail-suspended rats, which counteracted cancellous bone loss. Concomitant use of vitamin K2 with a bisphosphonate ameliorated the suppression of bone formation and more effectively prevented cancellous bone loss in tail-suspended rats. Vitamin K2 stimulated renal calcium reabsorption, retarded the increase in serum parathyroid hormone levels, and attenuated cortical bone loss primarily by suppressing bone resorption in calcium-deficient rats while maintaining the strength of the long bone in rats with magnesium deficiency. These findings suggest that vitamin K2 may not only stimulate bone formation, but may also suppress bone resorption. Thus, vitamin K2 could regulate bone metabolism in rats, which represented the various models of osteoporosis. However, the effects of vitamin K2 on bone mass and bone metabolism seem to be modest.
Vitamin K 2/chemistry/metabolism/*pharmacology ; Tomography, X-Ray Computed ; Tibia/pathology ; Rats ; Osteoporosis/*drug therapy/*prevention & control ; Male ; Magnesium Deficiency/diagnosis ; Magnesium/metabolism ; Homeostasis ; Female ; *Disease Models, Animal ; Diphosphonates ; Calcium/metabolism ; Bone and Bones/*drug effects/metabolism ; Bone Resorption ; Bone Diseases, Metabolic/*metabolism ; Animals