Advanced Imaging Techniques

Objectives Identify advanced CT imaging techniques Differentiate between and describe the applications of advanced imaging techniques Identify pathologies diagnosed using advanced CT imaging techniques After completing this topic, you should be able to: Identify advanced CT imaging techniques Differentiate between and describe the applications of advanced imaging techniques Identify pathologies that are diagnosed using advanced CT imaging techniques

TRAUMA CT is a trauma imaging modality and CT exams play an essential role in treating trauma patients. Due to the speed of image acquisition, CT exams are included in routine trauma protocols. Patients frequently need a CT prior to surgery to determine the extent of injury, locate internal bleeding, and determine the necessary course of treatment. In these images, the patient has endured obvious head trauma. Multiple skull fractures accompanying brain hemorrhage are demonstrated.

TRAUMA Evaluating fractures with CT has been an acceptable practice for some time. Recently, the resolution of these images has improved tremendously with multidetector CT systems. 3D imaging is made possible with the use of sophisticated CT software programs. Patients are scanned one time and images are manipulated via post-processing to create a 3D view of anatomical structures. These images are used for surgical guidance in the operating room.

CTA Computed Tomography Angiography studies have revolutionized how vessel abnormalities and clots are diagnosed. Historically, long and invasive catheterization procedures were used to evaluate for aneurysm and clots. Now, CT is becoming the gold standard for evaluating pulmonary emboli and abdominal aortic aneurysms via CTA studies. In image A, an abdominal aortic aneurysm is detected. Image B shows the aneurysm following the placement of an endograft stent.

CTV In addition to CTA studies, CTV exams are also being performed using CT. CTV or Computed Tomography Venography procedures evaluate the veins. Arteries are typically visualized immediately following a rapid injection of contrast. Adjusting scan times is necessary to evaluate the veins instead of the arteries.

BIOPSIES CT provides precise guidance for biopsies. The patient is positioned on the table based upon the easiest entry to retrieve a tissue sample for evaluation. These images show CT guided lung biopsies. Following the biopsy, the lungs are scanned again and a lung window algorithm is applied, to identify a potential pneumothorax caused from the procedure.

DRAINAGES Abscesses are fluid-filled collections of infection that can occur in solid organs or body cavities. CT is often utilized to provide guidance to aspirate fluid and insert a tube to drain the infection out of the body. These images demonstrate an abscess and then a drainage tube placed under CT guidance.

CT UROGRAPHY IVP used to be the routine exam for evaluating pathologies in the urinary system. In recent years, the IVP has become obsolete as physicians are turning to CT to diagnose renal stones. Stone protocols are typically performed without IV or oral contrast. The scans are fast and reliable for identifying stones within the urinary tract. The use of CT diagnosing stones is standard in most facilities. However, what if the patient has hematuria and tumors are a concern? CT urography studies are now used to evaluate for these pathologies.

TRANSPLANTS Live donors Kidney and liver transplants Pre-surgical evaluation Live donor transplants are exceeding cadaver transplants. As a result, CT scans are being used to evaluate the overall health of the potential donor, the viability of the organ to be transplanted, and assists in the pre-surgical evaluation of the organ transplant procedure.

SURGICAL PLANNING The value of CT as a diagnostic tool is appreciated throughout the medical community. The use of CT in surgical planning is no exception. In these images an abdominal aortic aneurysm is identified. Multiplanar imaging can demonstrate the aneurysm from different perspectives which aids in the surgical planning of complex cases.

CT PERFUSION CT perfusion studies incorporate a special software to evaluate blood flow to a particular organ. These images demonstrate a CT perfusion study of the brain. Most often, CT perfusion is used to evaluate acute CVA.

CT VIRTUAL COLONOSCOPY Virtual CT scans have become an alternative imaging tool for parts of the body typically evaluated with an endoscope. One such exam is a virtual colonoscopy. Virtual colonoscopy provides detailed imaging of polyps and tumors within the colon. Besides its diagnostic use for evaluating potential malignancies in the colon, virtual endoscopy studies are being performed to evaluate other areas of the body such as the lungs, stomach, and small intestines. Virtual studies are less invasive and do not require sedation as with routine endoscopy and colonoscopy procedures. Another fascinating use of this technology are virtual CT autopsies. The benefit for performing virtual CT autopsies are the images acquired become a permanent record of the patient’s injuries that resulted in death.

CARDIAC CT Cardiac CT is an emerging advanced imaging technique. The speed of the scanners accompanied with precise CT slices provide detailed images of heart anatomy. Rapid image acquisition permits the visualization of anatomy without motion artifacts. Besides identifying heart anatomy, the physiology or function of the heart, can be evaluated as well during these CT scans. Benefits of cardiac CT studies include a lower radiation dose and a less invasive test compared with routine heart catheterization procedures. CT has not replaced the necessity of heart catheterizations. However, it is providing essential diagnostic information for predicting the likelihood a cardiac event may occur.

RADIATION TREATMENT PLANNING CT is used as a planning tool for radiation treatment. Tumors are isolated and a course of treatment is determined to direct the high energy radiation to the malignancy while preserving surrounding healthy tissues. Radiation treatment planning often begins with a CT. The patient is positioned on the immobilization device that will be used for the radiation treatment. Low dose scans are completed for tumor localization. Scans should include the soft tissue and skin in its entirety as all tissue must be identified when treatment plans are developed. Radiation oncologists, dosimetrists, and physicists use the CT scans to assist with dose calculations.

PORTABLE CT DID YOU KNOW THAT CT HAS PORTABLE CAPABILITIES???? WHAT WILL THE FUTURE HOLD FOR CT IMAGING? Did you know that CT has portable capabilities? CT portable machines are being used in the ICU and Operating Room within hospitals. These units typically have smaller gantry apertures with a smaller Scan Field of View ideal for imaging the head. Besides its application in the ICU and OR, portable CT is being installed inside of ambulances to diagnose acute CVA while in transport to the hospital. With the use of CT technology, strokes are evaluated faster and intervention to save brain tissue can begin before arriving at the hospital. With the development of CT, trauma imaging has been transformed! Pathologies are diagnosed with such precision and accuracy providing a more positive prognosis for patients. CT is utilized as a surgical tool in the operating room giving surgeons the ability to see injuries in multiple dimensions. Advanced CT imaging techniques provide less invasive alternatives for imaging vasculature, the GI track, and the heart. What will the future hold for CT imaging? We are only limited by our imaginations!