Medical Imaging Analysis Report

I. Radiological Findings

Based on the provided pelvic CT scan images, the following main characteristics are observed:

• In the iliac bone and surrounding hard bony structures, there are irregular or “bubble-like” low-density areas, indicating the presence of gas within the bone and adjacent soft tissues.
• No obvious fracture lines are visible in the bone structure, but some trabecular structures appear blurred, suggesting possible inflammatory destruction.
• Signs of inflammatory changes can be observed in the surrounding soft tissues, such as swelling and the spread of bubble-like low-density areas.
• The lesions are primarily distributed in the pelvic region, involving scattered gas shadows in areas such as both pubic rami and the iliac bones.

These findings raise a strong suspicion of a gas-producing bone and soft tissue infection.

II. Potential Diagnoses

1. Emphysematous Osteomyelitis
   This condition is commonly seen in bones with rich blood supply, especially in patients with diabetes, immunocompromise, or chronic kidney disease. On CT, it is characterized by prominent gas within the bone and surrounding soft tissues, often appearing as multiple foamy or irregular shapes. In this case, the blood culture suggests Escherichia coli, a gram-negative bacterium often associated with this type of infection (and potentially anaerobes as well).
2. Vacuum Phenomenon
   This phenomenon is more frequently observed in degenerative spinal disorders or osteoarthritic changes, occasionally in osteonecrosis, vertebral collapse, or malignant tumors. The gas generally appears in linear or banded shapes with well-defined margins, mostly limited to the intervertebral disc or joint space. In this case, the gas distribution is more “foamy” or “honeycombed” and is accompanied by significant infectious symptoms, making a simple vacuum phenomenon less likely.
3. Bone Necrosis or Malignancy with Secondary Infection
   If bone destruction or a tumor is present and becomes secondarily infected, theoretically gas can form. However, this patient’s presentation with acute fever and a positive blood culture, along with multiple irregular gas shadows on imaging, aligns more closely with a gas-producing or purulent osteomyelitis.

III. Most Likely Final Diagnosis

Considering the patient’s advanced age, diabetes, and chronic kidney disease background, the detection of Escherichia coli in blood cultures, and the highly characteristic CT finding of intraosseous gas, the most likely diagnosis is:

Emphysematous Osteomyelitis (Gas-Producing Osteomyelitis).

This diagnosis carries a high mortality rate and significant risk, requiring prompt and aggressive antimicrobial therapy and surgical intervention.

IV. Treatment Plan and Rehabilitation

1. Treatment Strategy

• Antimicrobial Therapy: Select antibiotics that Escherichia coli is sensitive to, based on blood culture and susceptibility results, such as carbapenems or broad-spectrum cephalosporins, and include coverage for anaerobes if necessary.
• Surgical Intervention: If there is significant bony destruction or abscess formation, surgical debridement may be considered. Depending on the extent of bone damage, partial resection or drainage may be required.
• Supportive Care: Control blood glucose, correct electrolyte imbalances, and improve nutritional status. These measures are crucial for successful treatment outcomes.

2. Rehabilitation / Exercise Prescription Recommendations

Since the patient has diabetes and accompanying bone infection, with relatively fragile bones, avoid high-intensity or weight-bearing exercises in the early stage.

• Phase I (Acute Infection/Postoperative Early Stage):
  Focus on bed rest or seated mild activity, avoiding excessive load on the infected site. The main goal is to promote circulation and prevent muscle atrophy. During this phase, low-intensity isometric exercises for the lower limbs or trunk muscles can be performed 2-3 times a day, 5-10 minutes each session.
• Phase II (Inflammation Control Stage):
  After achieving basic control of the infection with antimicrobial treatment, gradually increase passive-to-active range-of-motion exercises for the pelvic area and lower limbs. Weight-bearing exercises should be introduced slowly, based on bone healing status. Low-intensity aerobic activities like seated leg raises or short walks can be performed 3-5 times a week, 15-20 minutes each session, avoiding strenuous activities.
• Phase III (Recovery Stage):
  Once imaging and inflammatory markers indicate stable bone healing, consider moderate-intensity resistance training (e.g., using resistance bands), and gradually extend walking time up to about 30 minutes, 3-5 times a week. Throughout the entire process, monitor blood glucose and renal function to adjust exercise intensity accordingly.

The entire rehabilitation plan should follow the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, Volume), continually assessing the infection status and blood glucose control. Avoid overload or exercise that might lead to fractures or other complications.