A system configured for determining regions of hyperdense lung parenchyma in an image of a lung, the system comprising: a memory comprising instruction data representing a set of instructions; a processor configured to communicate with the memory and to execute the set of instructions, wherein the set of instructions, when executed by the processor, cause the processor to: locate a plurality of vessels in the image; determine a density of lung parenchyma in a region of the image that neighbours a located vessel; and determine whether the region of the image comprises hyperdense lung parenchyma based on the determined density, hyperdense lung parenchyma having a density greater than -800 HU, characterized in that the set of instructions, when executed by the processor, further cause the processor to: determine a location of a hyperdense region in the image where the density of the hyperdense region is greater than -800 HU; compare the location of the determined hyperdense region to the location of the located vessels in the image; and determine that the hyperdense region comprises pleural effusion if the hyperdense region does not comprise any vessels. a memory comprising instruction data representing a set of instructions; a processor configured to communicate with the memory and to execute the set of instructions, wherein the set of instructions, when executed by the processor, cause the processor to: locate a plurality of vessels in the image; determine a density of lung parenchyma in a region of the image that neighbours a located vessel; and determine whether the region of the image comprises hyperdense lung parenchyma based on the determined density, hyperdense lung parenchyma having a density greater than -800 HU, characterized in that the set of instructions, when executed by the processor, further cause the processor to: determine a location of a hyperdense region in the image where the density of the hyperdense region is greater than -800 HU; compare the location of the determined hyperdense region to the location of the located vessels in the image; and determine that the hyperdense region comprises pleural effusion if the hyperdense region does not comprise any vessels. locate a plurality of vessels in the image; determine a density of lung parenchyma in a region of the image that neighbours a located vessel; and determine whether the region of the image comprises hyperdense lung parenchyma based on the determined density, hyperdense lung parenchyma having a density greater than -800 HU, characterized in that the set of instructions, when executed by the processor, further cause the processor to: determine a location of a hyperdense region in the image where the density of the hyperdense region is greater than -800 HU; compare the location of the determined hyperdense region to the location of the located vessels in the image; and determine that the hyperdense region comprises pleural effusion if the hyperdense region does not comprise any vessels. determine a location of a hyperdense region in the image where the density of the hyperdense region is greater than -800 HU; compare the location of the determined hyperdense region to the location of the located vessels in the image; and determine that the hyperdense region comprises pleural effusion if the hyperdense region does not comprise any vessels.