Comparison of MRI and CT Scan for the Detection of Liver Cancer.

OBJECTIVE: The objective of the paper was to compare the value of CT and MRI in the diagnosis of primary carcinoma of the liver. METHODS: A retrospective analysis was performed on 132 cases of suspected primary liver carcinoma. CT and MRI diagnosis were performed and pathological results were compared to determine the diagnostic value of the two methods. RESULTS: 96 cases were diagnosed as primary liver carcinoma by pathological examination after operation. The total detection rate of 96 lesions through MRI was 93.75%, while 84.38% through CT (P<0.05). For lesions with a <3 cm diameter, the CT detection rates of lesions in the plain, arterial, portal, and equilibrium phases were 52.94%, 73.53%, 58.82%, and 58.82% respectively. For lesions with a diameter ≥ 3 cm, the CT detection rate was 80.65 %, 93.55%, 85.48%, and 83.87%, respectively (P<0.05). For lesions with <3cm diameter, the MRI detection rates of lesions in the T1WI, T2WI, LAVA arterial phase, LAVA portal phase, and LAVA balance phase were 61.76%, 76.47%, 88.24%, 79.41%, and 52.94%, respectively, and for lesions with ≥3cm diameter, the detection rates of MRI were 77.42%, 87.10%, 91.94%, 90.32%, and 90.32%, respectively, and the detection rate of lesions with ≥3cm diameter in the balance phase of LAVA was higher (P<0.05). Taking pathological results as the gold standard, the sensitivity of diagnosing primary liver carcinoma through CT is 81.25%, specificity is 75.00%, accuracy is 79.55%, the positive predictive value is 89.66%, the negative predictive value is 60.00%, and the values of the same parameters for the MRI are 93.75. %, 86.11%, 91.67%, 94.74%, and 83.78% respectively. CONCLUSION: Both CT and MRI have diagnostic value for primary liver carcinoma. The comparison showed that MRI has a higher diagnostic value and higher detection rate for small lesions. However, the actual process of diagnosis cannot rely solely on MRI, and a comprehensive combination of diagnosis methods will be effective.

Changes in the stoichiometry of Castanopsis fargesii along an elevation gradient in a Chinese subtropical forest.

Elevation is important for determining the nutrient biogeochemical cycle in forest ecosystems. Changes in the ecological stoichiometry of nutrients along an elevation gradient can be used to predict how an element cycle responds in the midst of global climate change. We investigated changes in concentrations of and relationships between nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in the leaves and roots of the dominant tree species, Castanopsis fargesii, along an elevation gradient (from 500 to 1,000 m above mean sea level) in a subtropical natural forest in China. We analyzed correlations between C. fargesii's above-ground biomass and stoichiometry with environmental factors. We also analyzed the soil and plant stoichiometry of this C. fargesii population. Our results showed that leaf N decreased while leaf K and Ca increased at higher elevations. Meanwhile, leaf P showed no relationship with elevation. The leaf N:P indicated that C. fargesii was limited by N. Elevation gradients contributed 46.40% of the total variance of ecological stoichiometry when assessing environmental factors. Our research may provide a theoretical basis for the biogeochemical cycle along with better forest management and fertilization for this C. fargesii population.