Domain: Healthcare — Imaging Medicine
Target concept: CT Unenhanced Imaging Manifestations of Cirrhosis

Video generation prompt: Perform a CT plain scan of the abdomen in a patient with liver cirrhosis, and observe the liver's morphology and density, as well as the width of the portal vein.

Evaluation guide:
(i) Target concept: Visual identification of diagnostic CT signs of uncomplicated liver cirrhosis on non-contrast axial imaging.
Minimum mechanism: The video must depict a static or smoothly drifting axial CT slice where grayscale intensity and spatial arrangement encode anatomical truth: liver surface geometry, portal vein caliber dominance, and liver-spleen density hierarchy must emerge solely from pixel luminance and structural layout, without annotation or narration.
(ii)Storyline: Frame 1–3: Stable axial view of upper abdomen enters field; liver occupies right upper quadrant with irregular margin and prominent caudate segment. Frame 4–7: Portal vein emerges clearly at hilum as a central, round, high-density tube, visibly thicker than branching vessels radiating into liver. Frame 8–10: Liver parenchyma displays uniform mid-gray tone distinctly lighter than adjacent spleen (same slice, same contrast window); no contrast enhancement, no motion artifact, no extraneous elements; entire sequence observed from fixed anterior-posterior viewpoint with consistent lighting and scaling.

Manual:
Experimental Procedure
1. Position patient supine for abdominal CT plain scan.
2. Acquire axial non-contrast CT images at hepatic hilum level.
3. Display single representative slice showing liver and portal vein.
Observation of Experimental Phenomena
- Liver exhibits irregular surface contour (nodular/undulating edge) and disproportionate caudate lobe size.
- Portal vein appears as a round-to-oval, homogeneous high-density tubular structure at the hilum, wider than adjacent intrahepatic branches.
- Liver parenchyma density is uniformly lower than spleen.
Summary of Experimental Principles
CT unenhanced imaging manifestations of cirrhosis include: (1) morphologic changes—surface nodularity, right lobe atrophy, caudate lobe hypertrophy; (2) density reduction due to fibrofatty infiltration; (3) portal vein widening reflecting portal hypertension.

Prompt Grounding rubric:
level_1: No abdominal CT image is shown; or no liver is visible; or no portal vein is visible; or the image is not a grayscale axial CT slice (e.g., it is a color image, an external photo, or a diagram).
level_2: A CT-like grayscale abdominal image appears, but the liver cannot be identified as a distinct organ, or no portal vein structure is shown within the liver, or the slice is not a clear upper-abdominal axial cross-section.
level_3: An axial non-contrast CT slice of the upper abdomen is shown; the liver is identifiable in the right upper quadrant by its shape and position; a tubular portal vein structure is visible at the liver hilum; but the liver's surface contour or the vein's appearance is not clearly rendered.
level_4: Everything required for score 3 is shown, and in addition: the liver's surface contour is rendered with visible irregularity (an uneven, nodular edge rather than a perfectly smooth one); the portal vein appears as a distinct, round-to-oval tubular structure at the hilum; the image shows no sign of injected contrast (e.g., no bright-white vessels); the liver, portal vein, and adjacent spleen are all visible in one unobstructed, fixed-viewpoint frame.
level_5: Everything required for score 4 is shown, and in addition: the liver's irregular surface, the portal vein, and the spleen are all simultaneously in full view with nothing cropped, overlapping, or covered by labels, arrows, or UI elements; the axial slice stays stable at the hepatic-hilum level without drifting away; image brightness and scale stay constant throughout the clip.

Scientific and Causal Correctness rubric:
level_1: The image shows signs that contradict cirrhosis: a smooth, regular liver edge; a portal vein no wider than its branches; liver tissue that is the same shade as or darker than the spleen; or any sign of injected contrast.
level_2: The liver's edge looks essentially normal (smooth, regular) and its density looks about the same as the spleen's, and/or the portal vein looks no wider than a typical intrahepatic branch, and/or the portal vein appears artificially bright as if contrast had been given.
level_3: The liver shows at least one visible sign consistent with cirrhosis (an irregular, nodular edge, or an enlarged caudate lobe relative to the rest of the liver); the portal vein is visible and shows no sign of contrast enhancement; but the video does not clearly show the portal vein as wider than its branches, and liver density is not visibly compared against the spleen.
level_4: Everything required for score 3 holds, and in addition: the portal vein's main trunk is visibly wider than the first branch vessels it divides into, seen in the same slice; the liver parenchyma looks visibly darker/grayer than the spleen shown in the same image; nothing appears that is inconsistent with plain cirrhosis (no bright spots suggesting gas in the portal vein, no calcified nodules, no focal mass).
level_5: Everything required for score 4 holds, and in addition: the liver shows both an irregular edge AND a visibly enlarged caudate lobe together; the portal vein's widened caliber is visible continuously from its main trunk through to where it branches at the hilum; the liver-vs-spleen density difference looks even and consistent across the whole visible liver, without patches or streaks that would suggest an imaging artifact rather than the real anatomy.

Spatiotemporal Consistency rubric:
level_1: The liver appears to jump to a different spot between frames; the portal vein blinks in and out of the image with no scrolling motion to explain it; or the slice position jumps vertically mid-video (e.g., the diaphragm appears then is gone, with no scroll shown in between).
level_2: The liver's outline changes shape abruptly between frames rather than through a smooth scroll or zoom; the portal vein flickers in and out of view; or the image brightness or apparent light source shifts partway through with no on-screen reason.
level_3: There is a small amount of jitter in the image's position, a brief dip or rise in brightness, or a moment where the portal vein is briefly covered by a label, but aside from that, the liver's shape and the portal vein's location stay stable and anatomically consistent across the whole video.
level_4: Everything required for score 3 holds, and in addition: the liver stays centered in the upper abdomen and the portal vein stays anchored at the hepatic hilum in every frame; no structure stretches or warps; the image's brightness and gray-level range stay constant; there are no frozen frames, dropped frames, or sudden zooms.
level_5: Everything required for score 4 holds, and in addition: any scroll or zoom happens at a smooth, steady pace with no sudden speed changes; the liver and portal vein never drift out of alignment between frames; the slice only ever moves in one direction (it never appears to scroll forward and then backward).