**Core Concept**
Bone infections, such as osteomyelitis, can be challenging to diagnose in their early stages due to non-specific symptoms. The most sensitive investigation for early bone infections involves detecting the presence of infection biomarkers or direct visualization of infected tissue.

**Why the Correct Answer is Right**
The correct answer, Technetium-99m-MDP bone scan, is highly sensitive for detecting early bone infections. This imaging technique utilizes a radiopharmaceutical that is taken up by active bone-forming cells, allowing for the identification of areas of increased bone turnover and inflammation. The technetium-99m-MDP bone scan can detect infections as early as 24-48 hours after the onset of symptoms, making it an essential tool in the diagnosis of osteomyelitis.

**Why Each Wrong Option is Incorrect**
**Option A:** MRI is highly sensitive for detecting soft tissue involvement and bone marrow edema but is not the most sensitive investigation for early bone infections.
**Option B:** CT scans are useful for detecting cortical bone involvement but are not as sensitive as bone scans for early bone infections.
**Option C:** X-rays are often normal in early bone infections and are not sensitive enough to detect the early signs of osteomyelitis.

**Clinical Pearl / High-Yield Fact**
In cases of suspected bone infection, a Technetium-99m-MDP bone scan should be performed as soon as possible, ideally within 24-48 hours of symptom onset, to facilitate early diagnosis and treatment.

**Correct Answer: C. CT scans are useful for detecting cortical bone involvement but are not as sensitive as bone scans for early bone infections.