Update README.md

README.md

@@ -61,8 +61,14 @@ histopathology slides. Its LLM component is trained on a diverse set of medical
 data, including radiology images, histopathology patches, ophthalmology images,
 and dermatology images.
 
+MedGemma 4B is available in both pre-trained (suffix: `-pt`) and
+instruction-tuned (suffix `-it`) versions. The instruction-tuned version is a
+better starting point for most applications. The pre-trained version notably
+achieves better performance on MIMIC-style chest X-ray reporting.
+
 MedGemma 27B has been trained exclusively on medical text and optimized for
-inference-time computation.
+inference-time computation. MedGemma 27B is only available as an
+instruction-tuned model.
 
 MedGemma variants have been evaluated on a range of clinically relevant
 benchmarks to illustrate their baseline performance. These include both open