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Radiology Handbook

Computerized Tomography – Body


Computerized Tomography – Body Quick Links CT of the Chest High Resolution CT of the Chest CT of the Abdomen And Pelvis CT-Extremities

NON-IONIC INTRAVENOUS CONTRAST MATERIAL IS USED FOR ALL CT PATIENTS

CT OF THE CHEST

 

Description:

Patient lies in a supine position and is scanned generally with intravenous contrast material. Axial sections are acquired using 1-10mm slice thickness depending on the region of anatomy to be surveyed and the study indications. Routine studies are performed from the level of the apices through the adrenals.

Indications:

  1. Diagnosis and staging of suspected mediastinal mass lesions.

  2. Evaluation of mediastinal adenopathy when staging neoplasms (e.g. primary lung carcinoma, lymphoma) or evaluating infectious diseases (e.g. TB).

  3. Staging of esophageal carcinoma.

  4. Differentiation of pleural and parenchymal lung processes.

  5. Diagnosis and staging of chest wall masses.

  6. To search for occult pulmonary metastases.

  7. To identify chest wall involvement in peripheral lung masses.

  8. To help differentiate hilar adenopathy from prominent pulmonary vasculature.


  9. Diagnosis and staging of endobronchial lesions.

  10. Evaluation of suspected AVM's, bronchogenic cysts, pulmonary sequestration.

  11. Localization of loculated areas of pleural effusion or pneumothorax.

  12. Trauma survey (aortic or other mediastinal vascular injury, rib fractures, pneumothorax, bronchial fracture, etc.).

  13. Localization of thoracic lesions for biopsy (see “Percutaneous Biopsy of the Lung or Mediastinum) or drainage procedures..

  14. Evaluation of suspected aortic dissection.

  15. Evaluation of suspected chronic central pulmonary thromboemboli.

  16. Evaluation of suspected acute pulmonary emboli in selected patients (subsegmental emboli are not generally detected).

Preparation:

Patient should remain NPO 3 hrs. prior to examination.

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HIGH RESOLUTION CT OF THE CHEST

 

Description:

Patient lies either supine or prone and 1mm thick high-resolution sections are obtained through the regions of interest. Routinely performed in inspiration; in selected cases, supplemented by scans in expiration.

Indications:

  1. Evaluation of interstitial lung disease

  2. Evaluation of hemoptysis

  3. Search for bronchiectasis

  4. Evaluation of pulmonary nodule for presence of calcification or fat., to help differentiate a benign calcified granuloma or hamartoma from a potentially malignant lesion.

  5. Evaluation of emphysema.

  6. Evaluation of air-trapping (e.g. bronchiolitis obliterans).

Preparation:

None. IV contrast not routinely utilized.

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CT OF THE ABDOMEN AND PELVIS

 

Description:

Each study is tailored and is prospectively protocoled based on the patient's symptoms and clinical history. Slice section thickness may vary between 1.5mm and 5mm depending on the region of interest targeted.

Indications:

  1. Diagnosis and staging of abdominal, pelvic, or extraabdominal malignancy.

  2. Palpable mass.

  3. Suspected abdominal aortic aneurysm, postoperative evaluation of stent or graft patency.

  4. Suspected intra-abdominal, pelvic, or retroperitoneal abscess.

  5. Evaluation of jaundice, weight loss, abdominal or pelvic pain, fever of suspected abdominal source, abnormal liver function tests, anemia.

  6. Evaluation of lympadenopathy (lymphoproliferative disease).

  7. Suspected inflammatory processes, such as:
    1. Appendicitis
    2. Diverticulitis
    3. Ileitis
    4. Colitis
    5. Pyelonephritis
    6. Cholecystitis
    7. Pancreatitis
    8. Peritonitis
    9. Hepatitis


  8. Suspected bowel obstruction or bowel ischemia.

  9. Trauma survey:
    1. Visceral lacerations (liver, spleen, kidney, pancreas, gallbladder, bowel)
    2. Hemoperitoneum
    3. Disruption of urinary collecting system, bladder rupture


  10. Evaluation of suspected organ perforation

  11. Characterization of hepatic mass lesions noted on other imaging modalities

  12. Characterization of renal lesions noted on other imaging modalities

  13. Evaluation of post-operative and post-organ transplantation patients

Preparation:

Bowel prep:
Patients are generally asked to drink approximately 800-1000ml of dilute barium as part of the oral contrast prep. This is administered in the CT department starting approximately 45 minutes to one hour before the examination. Water-soluble contrast (gastrografin) is utilized in intensive care unit, and preoperative patients as well as those with suspected bowel perforation (ICU patients usually receive gastrografin bowel preps in the ICU before being transported to the CT department). Patients being evaluated for rectosigmoid carcinoma or pelvic gynecologic mass lesions may receive gentle air insufflation of the colon or contrast material per rectum. Whenever possible, patients should always undergo a CT examination prior to an upper GI, barium enema, or small bowel study. It is not possible to perform a diagnostic Body CT study if residual barium is present within the GI tract. Additionally, it is preferable to evaluate the pancreas and biliary system prior to the patient undergoing either ERCP or biliary stenting procedures whenever possible.

Intravenous contrast:
All patients routinely receive iodinated intravenous contrast material Patient's should be kept NPO for at least 3 hours prior to their examination. Any patient with a history of reaction to intravenous contrast should be premedicated. This is ABSOLUTELY ESSENTIAL for any patient with a history of anaphylaxis to contrast!

Currently recommended:

  1. PREDNISONE:,50mg po given 12 and 2 hours,prior to study, OR, METHYLPREDNIZOLONE, 32 mg po given 12 and 2 hours prior to study.


  2. BENADRYL: 25 or 50mg po given 1 hour prior to study.

Complications:

A contrast reaction to the intravenous contrast material is a possibility, even after steroid premedication.

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CT-EXTREMITIES

 

Description:

Axial images at 1cm, 3mm, or 5mm levels are made through the area of interest. Scans may be made after injection of intravenous contrast material or without contrast.

Indications:

  1. Soft tissue mass.

  2. To evaluate the extent of a known soft tissue tumor.

  3. To evaluate the extent of a bone tumor.

  4. To localize a foreign body.

  5. To evaluate the meniscus in the knee.

  6. To evaluate a complex fracture.

Complications:

Contrast reaction.

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Last Updated:12/19/06 ALK