From the grocery store
Seven things from the shop, six contrasts
Acquired on the AltraMRI 0.4T system on 8 and 9 November 2026. A pork hock, a grapefruit, a pomegranate, three duck eggs, three kiwis, an avocado and a bell pepper, each run through the same fore-foot protocol as the phantom: pilot, proton density, T1, T2, T2* and STIR, twelve 5 mm slices, 170 mm field of view, 1 mm in-plane voxels. Nothing was changed between objects except the object.
Meat counter
Pork hock: Skin, fat, muscle, tendon, bone
A transverse slice through a pork hock: the closest thing to a limb that a supermarket sells. Read it as you would a horse: skin and subcutaneous fat at the rim, muscle bellies and tendons around two joint ends, cortical bone black on everything.
Slice 11 of 12. Same slice, six sequences.
Produce
Grapefruit: Membranes one millimetre thick
The MRI textbook fruit. Juice vesicles are almost pure water, the segment membranes and pith are nearly dry, and the peel carries oil glands. The question it answers is resolution: can the septa be followed from core to rind?
Slice 3 of 12. Same slice, six sequences.
Produce
Pomegranate: Water content is not contrast
Every part of a pomegranate is wet, so proton density and T1 show almost nothing. On T2 each aril appears as a bright sac of juice around its dark seed, several hundred of them in one slice. Relaxation, not water content, makes the picture.
Slice 10 of 12. Same slice, six sequences.
From home
Duck eggs: Fat, water and cooked protein
Three duck eggs standing on end: one raw, one hard-boiled, one salt-cured. Two marker tubes identify them. The small tube above the upper-left egg is MCT oil, so that egg is the salted one; the tube to the right of the right-hand egg is water, so that egg is raw; the unmarked egg at lower left is hard-boiled. Albumen is water and protein, yolk is a third lipid, and cooking or curing changes both.
Slice 7 of 12. Same slice, six sequences.
Produce
Kiwis: A ring of seeds a millimetre across
Three kiwis, whole. The flesh is uniform and wet; the interest is the ring of black seeds around the pale core and the fine radial fibres. Where the pomegranate tested contrast, this tests edge resolution on small, dark objects in a bright field.
Slice 9 of 12. Same slice, six sequences.
Produce
Avocado: A fruit that is partly fat
Avocado flesh is about fifteen percent oil held in a watery pulp, so it sits between the water-only fruit and the yolks. The stone is dry and dense. Ask one question of each image: does the flesh behave like water, like fat, or like a mixture?
Slice 11 of 12. Same slice, six sequences.
Produce
Bell pepper: Mostly air
A pepper is a thin wall of wet tissue around air, with a placenta and seeds at the centre. The wall is bright on everything. The test is the air interface: at high field the susceptibility step at air blooms on gradient echo and distorts the wall; at 0.4 T the step is eight times smaller.
Slice 9 of 12. Same slice, six sequences.
Dialling the null
Four inversion times, one slice
The protocol STIR uses TI 95 ms. The same slice of the hock was run again at 70, 120 and 135 ms. Subcutaneous fat is the thing to watch, then the boundaries.
The fat null for animal fat at 0.4 T sits between 95 and 120 ms, and the right side to err on is short: a slightly short TI costs a little fat suppression, a slightly long one costs edges. The protocol value of 95 ms, chosen on MCT oil in the phantom, holds on the real thing.
What it shows
Three things to take from the shopping
Real tissue behaves
Skin, fat, muscle, tendon, cartilage and cortical bone rank on every sequence exactly as the phantom media predicted they would, and the yolks and avocado flesh behave as the fat fractions they carry.
The null is right
Fat in the hock and lipid in the yolks suppress at the protocol inversion time, with the water marker and the fluid-rich tissues left bright.
Air draws no artefact
A pepper is mostly air. At 0.4 T the air-to-wall interface stays sharp even on gradient echo, where a high-field magnet would bloom. That matters in a hoof.
Reconstructions from the AltraMRI console, 8 and 9 November 2026, windowed per image; standard reconstruction, no further processing. Matrices are as acquired: readout oversampling and navigator echoes are not counted. The grapefruit was re-acquired on 9 November with the fast spin echo readout at the standard 168 samples; the fast spin echo and STIR images of the other objects, from 8 November, were run with 336 readout samples over the same field of view (0.5 × 0.9 mm nominal) and will be re-acquired. The scale on each image is in millimetres, from the acquisition field of view. Objects bought that morning in Littleton, Massachusetts; the eggs from our own ducks. No horse has been imaged on the 0.4T system yet.