Joseph K. T. Lee

Computed body tomography with MRI correlation

Chapter 1. CT Principles and Techniques, Including CTA Chapter 2. MRI: Basic Principles and Techniques Chapter 3. Interventional CT Technique, Including RF Ablation and CT Fluoroscopy Chapter 4. Neck Chapter 5. Thorax: Techniques and Normal Anatomy Chapter 6. Mediastinum Chapter 7. Lung Chapter 8. Pleura, Chest Wall and Diaphragm Chapter 9. Heart and Pericardium Chapter 10. Normal Abdominal and Pelvic Anatomy Chapter 11. Gastrointestinal Tract Chapter 12. Liver Chapter 13. Biliary Tract Chapter 14. Spleen Chapter 15. Pancreas Chapter 16. Abdominal Wall and Peritoneal Cavity Chapter 17. Retroperitoneum Chapter 18. Kidney Chapter 19. Adrenals Chapter 20. Pelvis Chapter 21. Trauma Chapter 22. Non-traumatic Acute Abdomen Chapter 23. Musculoskeletal Chapter 24. Spine Chapter 25. Pediatrics

Hepatocellular carcinoma of diffuse type: MR imaging findings and clinical manifestations

To assess MR imaging findings and clinical manifestations of diffuse‐type hepatocellular carcinoma (HCC).

CT and MR imaging of radiation hepatitis

The authors describe two cases of radiation hepatitis evaluated by magnetic resonance imaging and CT with CT angiography (CTA) additionally performed in one patient. On CT the radiation hepatitis appeared as sharply demarcated region of lower attenuation than the adjacent normal liver. The region of radiation hepatitis demonstrated decreased perfusion in the portal venous phase of CTA. and 4 min delayed images following CTA showed increased density or relative increased accumulation of contrast. Magnetic resonance in both cases showed that the area of low density on CT had high signal on the T2-weighted image and had increased water content as determined by proton spectroscopic imaging method.

Computed tomography in the staging of testicular neoplasms.

Twenty-six patients with primary testicular tumor were evaluated by computed tomography. It was highly accurate in differentiating lymph node metastases from testicular tumors. CT scanning may reveal tumor in lymph nodes not normally opacified during bipedal lymphangiography. It can also be used in treatment planning, follow-up, and in localizing sites of recurrence when serum tumor markers become positive. Some pitfalls of CT are also discussed.

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety).

The short‐term1 safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast‐enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 μmol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection‐associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short‐term risks from exposure to MnDPDP. J. Magn. Reson. Imaging 2000;12:186–197.

Assessment of Real-Time 3D Visualization for Cardiothoracic Diagnostic Evaluation and Surgery Planning

Rationale and ObjectivesRationale and Objectives: Three-dimensional (3D) real-time volume rendering has demonstrated improvements in clinical care for several areas of radiological imaging. We test whether advanced real-time rendering techniques combined with an effective user interface will allow radiologists and surgeons to improve their performance for cardiothoracic surgery planning and diagnostic evaluation.Material and MethodsMaterials and Methods: An interactive combination 3D and 2D visualization system developed at the University of North Carolina at Chapel Hill was compared against standard tiled 2D slice presentation on a viewbox. The system was evaluated for 23 complex cardiothoracic computed tomographic (CT) cases including heart–lung and lung transplantation, tumor resection, airway stent placement, repair of congenital heart defects, aortic aneurysm repair, and resection of pulmonary arteriovenous malformation. Radiologists and surgeons recorded their impressions with and without the use of the interactive visualization system.ResultsResults: The cardiothoracic surgeons reported positive benefits to using the 3D visualizations. The addition of the 3D visualization changed the surgical plan (65% of cases), increased the surgeon’s confidence (on average 40% per case), and correlated well with the anatomy found at surgery (95% of cases). The radiologists reported fewer and less major changes than the surgeons in their understanding of the case due to the 3D visualization. They found new findings or additional information about existing findings in 66% of the cases; however, they changed their radiology report in only 14% of the cases.ConclusionConclusion: With the appropriate choice of 3D real-time volume rendering and a well-designed user interface, both surgeons and radiologists benefit from viewing an interactive 3D visualization in addition to 2D images for surgery planning and diagnostic evaluation of complex cardiothoracic cases. This study finds that 3D visualization is especially helpful to the surgeon in understanding the case, and in communicating and planning the surgery. These results suggest that including real-time 3D visualization would be of clinical benefit for complex cardiothoracic CT cases.

Cavernous hemangioma of the liver: assessment of MR tissue specificity with a simplified T2 index.

This is a comparison of the ability of two quantitative magnetic resonance (MR) indices: (a) the second echo signal drop (SESD) (a simplified index of T2 relaxation times that we have developed); and (b) the previously described lesion/liver signal intensity ratio (LLR) to provide histologic diagnosis in hepatic lesions greater than 2 cm in diameter. In 55 patients 108 hepatic masses [31 cavernous hemangiomas (CH), 68 metastases, and 9 hepatocellular carcinomas] were scanned at 0.5 T. Statistically significant differences between CH and malignant lesions were obtained in mean SESD (p = 0.0006) and LLR (p = 0.0008) using repetition time (TR) 2,100/echo time (TE) 35, 60 ms. Application of cutoff values derived from receiver-operator characteristic analysis led to a correct diagnosis in 100 and 94% of lesions, respectively. Using TR 2,100/TE 35, 90 ms in a different patient population, CH and malignancies again displayed significantly different mean values, using the SESD (p = 0.0090) and LLR (p = 0.0024) methods. These measurements provided a correct diagnosis in 74 and 81%, respectively. Accuracy was increased in those cases in which the diagnosis by SESD and LLR were concordant. When compared with visual analysis, these quantitative methods appear to achieve near 100% accuracy in the differentiation of hepatic CH from malignancies.

Chemotherapy-treated liver metastases mimicking hemangiomas on MR images.

AbstractBackground: To report the observation that chemotherapy-treated liver metastases may mimic the appearance of hemangiomas on T2-weighted and serial postgadolinium gradient-echo magnetic resonance (MR) images. Methods: T2-weighted and serial postgadolinium spoiled gradient-echo images were prospectively and retrospectively analyzed in six patients. All patients had been treated with chemotherapy for a duration of 2–12 months. Histopathologic evaluation of liver lesions was performed in three patients. Results: Twelve lesions that resembled hemangiomas were identified. Lesions were 0.8–5.5 cm in diameter. All were well defined, oval or lobulated, and demonstrated decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. On immediate postgadolinium images, all lesions demonstrated peripheral nodular enhancement, which coalesced on delayed imaging. Final histopathologic diagnoses were as follows: hepatic metastases from colon cancer (two patients), ovarian cancer (two patients), pancreatic islet cell tumor (one patient), and breast cancer (one patient). Conclusions: Metastases treated by chemotherapy may mimic the appearance of hemangiomas on a variety of commonly employed MR techniques. In patients undergoing MR imaging for the evaluation of liver metastases, a history of prior chemotherapy administration and duration should be sought to prevent inaccurate staging and inappropriate therapeutic decision making.

Computed tomography in malignant endometrial neoplasms

Malignant uterine neoplasms are the most common invasive gynecological malignancies. The prognosis depends on the history, the grade, and the stage. Recent reports have stressed that a small percentage of patients with clinically low stage disease have unsuspected metastases. We retrospectively reviewed 61 patients with known malignant uterine neoplasms. In 18 patients with preoperative computed tomographic examinations, these scans detected unsuspected omental metastases in two and pelvic adenopathy in three. There was one false positive and one false negative examination. Computed tomography was superior to the clinical examination in defining the extent of the tumor in five patients. Computed tomography was also helpful in evaluating patients with suspected recurrent disease.

Percutaneous drainage of prostatic abscesses.

Percutaneous catheter drainage of intra-abdominal abscesses currently is a well established technique. We report on 2 anuric patients on maintenance hemodialysis who presented with a prostatic abscess. We elected to use a transperineal, percutaneous drainage technique. Adequate drainage was documented by pelvic computerized tomography scans and followup confirmed satisfactory long-term results.