Michael Y. M. Chen

Pericardial and visceral adipose tissues measured volumetrically with computed tomography are highly associated in type 2 diabetic families.

Rationale and Objectives:Pericardial and visceral adipose tissue volumes can provide new insight into the complex relation between obesity, adult-onset diabetes, and cardiovascular disease. We describe a new method for quantifying pericardial adipose tissue volumes with computed tomography (CT), and present its precision and relation to established measures of adiposity. Methods:Eighty subjects randomly selected from a family study of sibling pairs concordant for type 2 diabetes and unaffected siblings, 69 with diabetes, had 2 cardiac CT scans with electrocardiographic gating and 1 abdominal scan as part of an examination designed to measure calcified atherosclerotic plaque. Pericardial adipose tissue and visceral adipose tissue were measured using a 3-dimensional analysis technique. Body mass index, waist circumference, waist-to-hip ratio, and percent fat by dual x-ray absorptiometry were measured during the same visit. Results:Pericardial adipose tissue volumes measured independently and in a random order from the 2 sequential cardiac CT scans obtained during the same examination were highly correlated (Spearman R = 0.99; P <0.0001). The mean ± standard deviation (median) pericardial adipose tissue volume was 320.5 ± 147.3 (281.7) mL. Pericardial adipose tissue was highly correlated with total abdominal visceral adipose tissue (R = 0.81; P <0.0001). Conclusion:The significant association between pericardial and visceral adipose tissue volumes in this preliminary study suggests that pericardial, like visceral adipose tissue, may be an important predictor or risk factor for cardiovascular disease and other related illnesses and warrants further evaluation.

CAN NONCONTRAST HELICAL COMPUTED TOMOGRAPHY REPLACE INTRAVENOUS UROGRAPHY FOR EVALUATION OF PATIENTS WITH ACUTE URINARY TRACT COLIC

The objective of this study was to determine whether helical computed tomography (CT) performed without oral or intravenous contrast agents is accurate in the evaluation of patients with suspected acute renal colic. One hundred consecutive patients with suspected renal colic or ureteral colic were referred by our institutions emergency department for unenhanced helical CT scans. We reviewed the original radiographic report for each patient and recorded the size and location of ureteral calculi and other concurrent urinary tract calculi, if any. We also recorded the presence or absence of hydronephrosis, hydroureter, perinephric edema, and periureteral edema. A total of 49 patients had ureteral calculi, 17 patients had only renal calculi, and 34 patients had no stones. Forty-nine patients had ureteral calculi, and 40 (82%) of these 49 patients had associated CT signs including hydroureter and periureteral edema. Calculi were present in the proximal ureter in 11 patients, the midureter in seven patients, and the distal ureter including ureterovesical junction in 31 patients. Calculi were seen elsewhere in the urinary tract and renal pelvis in 44 patients. Other diagnostic tests and stone passage were used to confirm the CT diagnosis of ureteral stones. The sensitivity and specificity of helical CT in evaluating ureteral calculi were 100% and 94%, respectively. Sixteen extraurinary lesions were detected in 34 patients who had no urinary calculi. Most extraurinary lesions (81%) were deemed the cause of acute flank pain. The room time for CT averaged 26 min, compared to 69 min for intravenous urography (IVU). The charge for CT was

Assessment of rectal tumor infiltration utilizing endorectal MR imaging and comparison with endoscopic rectal sonography

600 compared to

Modified barium swallow: clinical and radiographic correlation and relation to feeding recommendations

400 for IVU in our institution. Unenhanced helical CT was fast and accurate in determining the cause of colic and proved to be highly accurate for emergency situations.

RADIO FREQUENCY ABLATION OF LUNG METASTASES FROM RENAL CELL CARCINOMA

The preoperative assessment of depth of invasion of rectal carcinoma is increasingly important as new treatment methodologies are developed. Accuracy of preoperative endorectal MR imaging was therefore compared with that of the endoscopic rectal sonography in determining depth of invasion of rectal carcinomas.

Interpretation of abdominal CT: Analysis of errors and their causes

Clinical and videofluoroscopic evaluation of swallowing were correlated to determine their agreement and relationship to feeding recommendations. We reviewed a total of 148 patients with swallowing difficulties, of which 93 (45 women, 48 men; mean age 62 years) were evaluated by both clinical and radiographic examinations. A variety of materials were used for clinical bedside evaluation of oral and pharyngeal function. Radiographic examination was done with variable viscosity materials and videotape recording of the oral cavity and pharynx. The severity of oral and pharyngeal abnormalities was graded and findings of the examinations were compared. The combined results of both evaluations generated an index of swallowing difficulty which was correlated to the type of diet used if oral feeding was recommended or to a nonoral route of nutrition. In the assessment of oral and pharyngeal dysfunction, clinical evaluation and radiographic examination correlated closely in 94% of patients; however, the status of pharyngeal function was not determined in 61 (66%) of the 93 patients by clinical examination alone. The combined swallowing index was calculated in 89 patients and its severity correlated significantly with the type of feeding recommended; 64 patients were placed on one of three types of diets and 25 had enteral feedings. In conclusion, combined clinical and radiographic examinations correlated well, but clinical evaluation alone was limited by failure to evaluate the pharynx in many patients. The swallowing severity correlated well with final feeding recommendations.

Noninvasive assessment of portomesenteric venous thrombosis: current concepts and imaging strategies.

Radio frequency ablation is an imaging guided percutaneous procedure using thermal energy to treat focal malignancies. It has been used to treat neoplasms in the liver, bone, head and neck, and lung.1, 2 Surgical resection is considered the only possibly curative treatment for pulmonary metastases from renal cell carcinoma. We report a case of lung metastases from renal cell carcinoma treated successfully with radio frequency ablation. CASE REPORT A 52-year-old man presented with 2 lung nodules considered to be pulmonary metastases from renal cell carcinoma. He had renal cell carcinoma of the left kidney diagnosed 2 years earlier, and was treated for relief of flank pain and hematuria with left radical nephrectomy. Two pulmonary metastases were present at radical nephrectomy. Chemotherapy with interferon, interleukin-2, vinblastine and 5-fluorouracil was prescribed within 4 months after nephrectomy because of pulmonary metastases. The pulmonary nodules initially grew while the patient was being treated with immunotherapy but decreased in size with fluorouracil. Chemotherapy was completely discontinued 14 months before the ablative therapy for the lung metastases. Physical examination was unremarkable. Plain radiograph and chest computerized tomography (CT) showed 2 parenchymal, peripheral pulmonary nodules, 2.4 1.9 cm. and 1.8 2 cm., in the right lower lobe (part A of figure). Pulmonary nodules were confirmed as metastatic renal cell carcinoma on a CT guided percutaneous biopsy of 1 lesion. Due to the high risk of recurrence and patient refusal to undergo further chemotherapy and surgery, percutaneous ablation was offered as a treatment option. CT guided percutaneous radio frequency ablation of the pulmonary nodules was performed with the patient under general anesthesia. A 17 gauge radio frequency electrode was inserted into the larger nodule and 2, 12-minute cycles of radio frequency treatment were applied. The radio frequency needle was then repositioned in the smaller nodule and a single 12-minute cycle of treatment was applied. After the procedure CT revealed a tiny pneumothorax and some perilesional ground-glass attenuation indicating thermal damage. The patient tolerated the procedure well and was sent home the same day. An asymptomatic pleural cutaneous fistula developed evidenced by subcutaneous gas seen on a followup chest radiograph, which resolved spontaneously without further treatment. Followup chest CT 12 months later showed no recurrence or new metastatic lesions either at the ablation treated sites or elsewhere in the lung (part B of figure). The patient was asymptomatic 16 months later with no evidence of recurrence or new metastases, and no additional treatment since tumor ablation.

FDG pet evaluation of head and neck cancer: Value of imaging the thorax

PURPOSE Our goal was to analyze those factors contributing to the error rate in the interpretation of abdominal CT scans at an academic medical center. METHOD From a total of 694 consecutive patients (329 male, 365 female), we evaluated the error rates of interpreting abdominal CT studies. The average patient age was 54 years. All abdominal CT studies were reviewed by three to five CT faculty radiologists on the morning after the studies were performed. The error rate was correlated with reader variability, the number of cases read per day, the presence of a resident, inpatient versus outpatient, organ systems, etc. The chi 2-test was used for statistical analysis. RESULTS A total of 56 errors were found in the reports of 53 patients (overall error rate = 7.6%). Of these errors, 19 were judged to be clinically significant and 7 affected patient management. A statistically significant difference in error rates was noted among the five faculty radiologists (3.6-16.1%, p = 0.00062). No significant correlates between error rates and any of the other variables could be established. CONCLUSION The primary determinant of error rates in body CT is the skill of the interpreting radiologist.

Role of angiography in the detection of aortic branch vessel injury after blunt thoracic trauma.

Rapid, noninvasive imaging strategies, especially multidetector spiral CT and CT angiography (CTA) as well as gadolinium-enhanced MR angiography (MRA), have facilitated early diagnosis of splanchnic venous thrombosis, a potentially lethal cause of intestinal ischemia. Single breath-hold volumetric acquisitions permit superior temporal and contrast resolution while eliminating motion artifact and suppressing respiratory misregistration. Increased spatial resolution is aided by thinner slice collimation. These cross-sectional imaging techniques are becoming a preferred noninvasive alternative to conventional selective mesenteric angiography with delayed imaging for venous evaluation and should be considered the primary diagnostic modalities for evaluating patients with high clinical suspicion of nonsurgical mesenteric ischemia.

Radiation exposure during ERCP: effect of a protective shield

Patients with primary tumors of the head and neck have been reported to have a high rate of synchronous primary tumors of the upper aerodigestive tract. This study was performed to determine whether inclusion of the thorax in the scan volume would be diagnostically useful for positron emission tomography (PET) with [F‐18] fluorodeoxy‐D‐glucose (FDG) in patients with primary tumors of the head and neck.