W. Dennis Foley

Computed tomography, ultrasonography, and endoscopic retrograde cholangiopancreatography in the diagnosis of pancreatic disease: A comparative study

A prospective study was performed comparing the sensitivity of computed tomography, ultrasonography, and endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of pancreatic disease. Forty patients with suspected pancreatic carcinoma, acute recurrent or chronic pancreatitis, and/ or jaundice were studied. CT was the most sensitive study in evaluation of pancreatitis. ERCP was most accurate in evaluation of pancreatic malignancy. Ultrasonography was the least sensitive method in detecting pancreatic disease and dilatation of the extrahepatic biliary ducts.

Periportal halo: a CT sign of liver disease.

Periportal halos are defined as circumferential zones of decreased attenuation identified around the peripheral or subsegmental portal venous branches on contrast-enhanced computed tomography (CT). These halos probably represent fluid or dilated lymphatics in the loose areolar zone around the portal triad structures. While this CT finding is nonspecific, it is abnormal and should prompt close scrutiny of the liver in search of an underlying etiology. Periportal halos which may be due to blood are commonly seen in patients with liver trauma. Periportal edema may cause this sign in patients with congestive heart failure and secondary liver congesion, hepatitis, or enlarged lymph nodes and tumors in the porta hepatis which obstruct lymphatic drainage. This CT sign has also been observed in liver transplants (probably secondary to disruption and engorgement of lymphatic channels) and in recipients of bone marrow transplants who might develop liver edema from microvenous occlusive disease. While the precise pathophysiologic basis of periportal tracking has not been proven, it represents a potentially important CT sign of occult liver disease.

Noninvasive Assessment of Liver Fibrosis in Adult Patients Following the Fontan Procedure

OBJECTIVE   Recent data indicate that patients after the Fontan procedure are at risk for significant liver dysfunction; however, the prevalence and extent of liver disease in the Fontan population remains unknown. Furthermore, limited data exist in regard to screening for liver disease in adult Fontan patients. We sought to determine the prevalence of liver disease in adult patients following the Fontan procedure using computed tomography (CT) and serum biomarkers of liver fibrosis. DESIGN   Adult Fontan patients underwent screening for liver disease as part of their annual evaluation. Screening consisted of laboratory evaluation and dual-phase liver CT scan. Laboratory evaluation included analysis of liver function, viral hepatitis serologies, and FibroSURE panel (LabCorp), a test that analyzes the results of serum biomarkers to provide a quantitative surrogate marker for liver fibrosis. RESULTS   Sixteen patients, mean age 30.3 (range 20-41) years, were enrolled in the study. Mean length of follow-up from time of Fontan palliation was 20.5 (range 11-33) years. No patients had serologic evidence of viral hepatitis or synthetic liver dysfunction. Twelve patients (75%) had abnormal FibroSURE scores, seven (44%) had elevated FibroSURE scores predictive of Metavir fibrosis stage F2 or greater on liver biopsy, and one (6%) had a FibroSURE score predictive of cirrhosis on biopsy. All 16 patients had abnormal radiologic liver findings identified on CT, including heterogeneous enhancement in 11 (69%), varices in six (38%), and liver nodules in five patients (31%). Length of time since Fontan surgery correlated significantly with an elevated FibroSURE score (P = .05) and having more CT scan abnormalities (P = .04). CONCLUSIONS   Liver fibrosis detected by serum biomarkers and dual phase CT scan is common in adult patients following the Fontan procedure. Further studies are needed to determine the long-term clinical significance of these findings.

Multidetector computed tomography and blunt thoracoabdominal trauma.

Computed tomography has had an increasing role in the evaluation of patients after blunt trauma. Important findings in thoracic trauma include acute traumatic aortic injury, pneumothorax, hemothorax, pulmonary contusions and lacerations, mediastinal hematoma, and diaphragmatic rupture. The solid abdominal viscera may lacerate; infarct; or suffer vascular, ductal, or pyelocalyceal disruption. The bladder and intestines may rupture. In abdominal pelvic trauma, the direction of applied force often results in an identifiable constellation of injuries. This article reviews how multidetector computed tomography (MDCT) is used in the trauma patient. Technical advances of increased cephalocaudad coverage speed and improved z-axis resolution intrinsic to MDCT, together with effective contrast utilization, make MDCT invaluable in the setting of trauma.

Prospective and retrospective ECG gating for thoracic CT angiography: a comparative study.

OBJECTIVE The objective of our study was to compare radiation dose, contrast load, thoracic aortic attenuation value, and image quality parameters of MDCT thoracic aortography performed with prospective and retrospective cardiac gating. MATERIALS AND METHODS Studies were performed on 80 patients (prospective ECG gating, n = 40; retrospective ECG gating, n = 40) either being evaluated for thoracic aortic aneurysm (n = 23) or aortic dissection (n = 36) or undergoing postsurgical or postintervention follow-up (n = 21). Image acquisition parameters and radiation dose (CT dose index volume [CTDI(vol)] and dose-length product [DLP]) were obtained from image archival data. Contrast load and aortic attenuation values were obtained from a data registry. The comparative degrees of motion artifact and banding artifact were assessed on parasagittal maximum-intensity-projection (MIP) images and reformatted images in the plane of the aortic valve. RESULTS CTDI(vol) and DLP in the prospective ECG-gating group was 28.8 +/- 2.12 mGy (mean +/- SD) and 833.7 +/- 115.77 mGy/cm, respectively, which are significantly lower (p < 0.001) than those values in the retrospective ECG-gating group (74.7 +/- 13.42 mGy and 2,547.3 +/- 553.27 mGy/cm). The average contrast load in the prospective gating group was 109.1 +/- 14.74 mL and in the retrospective gating group, 101.3 +/- 10.45 mL (p < 0.05). The average aortic attenuation values (in Hounsfield units) for the prospective and retrospective ECG-gated groups were 447.6 and 350.2 HU, respectively, for the mid ascending aorta, 413.6 and 325.7 HU for the mid aortic arch, 418.2 and 327.6 HU for the mid descending aorta, and 355.0 and 306.2 HU for the supraceliac aorta. Subjective scores of motion artifact and banding artifact were equivalent between the two groups. CONCLUSION Compared with retrospective ECG-gated thoracic CT angiography, prospective ECG-gated thoracic CT angiography was associated with a lower radiation dose, slightly increased contrast load, increased aortic attenuation values, and equivalent image quality.

Computed tomography angiography: principles and clinical applications.

&NA; Clinical applications of computed tomography (CT) angiography have increased with the improved technology of multidetector CT systems. Adequate contrast enhancement and the timing of image acquisition are key elements in producing technically adequate CT angiograms. This review article provides guidelines and protocols for four‐, eight‐ and 16‐channel multidetector systems in studies of the thoracoabdominal aorta, aortoiliac, and abdominal visceral vasculature, abdominal and extremity run‐off studies, and carotid/cerebral CT anglography.

Contrast-induced nephropathy after a second contrast exposure

Background: The risk of contrast-induced nephropathy (CIN) after repeated contrast exposure has not been evaluated. Methods: We prospectively evaluated the effects of two contrast exposures during an investigational study of a new computerized tomography (CT) scanner. Adult subjects who underwent a variety of contrast-enhanced imaging procedures with conventional apparatus, as part of routine care, were invited to undergo a second contrast-enhanced research scan. Subjects were required to have an estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m2 and a serum creatinine (sCr) value measured immediately prior to the second contrast exposure that was <125% of that measured prior to the first imaging study. Results: Twenty-eight subjects underwent a second contrast exposure after a mean interval of 20 ± 13 days (75% males, 89% Caucasians, 21% diabetics, mean age 60.6 ± 6 years, mean contrast volume 130 ± 42 mL). There was a significant increase in mean sCr and decline in eGFR after the second contrast exposure (sCr 0.93 ± 0.14 vs. 0.86 ± 0.15 mg/dL prior, p = 0.027; eGFR 83.9 ± 13.5 vs. 89.8 ± 13 mL/min/1.73 m2 prior, p = 0.028). Four subjects (14.3% of the population) developed CIN. Conclusion: Even in subjects with relatively preserved renal function there is a notable risk of CIN after repeated contrast exposure. This conclusion was unaltered by several sensitivity analyses.

The role of sonography in imaging of the biliary tract.

Sonography is the recommended initial imaging test in the evaluation of patients presenting with right upper quadrant pain or jaundice. Dependent upon clinical circumstances, the differential diagnosis includes choledocholithiasis, biliary stricture, or tumor. Sonography is very sensitive in detection of mechanical biliary obstruction and stone disease, although less sensitive for detection of obstructing tumors, including pancreatic carcinoma and cholangiocarcinoma. In patients with sonographically documented cholelithiasis and choledocholithiasis, laparoscopic cholecystectomy with operative clearance of the biliary stone disease is usually performed. In patients with clinically suspected biliary stone disease, without initial sonographic documentation of choledocholithiasis, endoscopic ultrasound or magnetic resonance cholangiopancreatography is the next logical imaging step. Endoscopic ultrasound documentation of choledocholithiasis in a postcholecystectomy patient should lead to retrograde cholangiography, sphincterotomy, and clearance of the ductal calculi by endoscopic catheter techniques. In patients with clinical and sonographic findings suggestive of malignant biliary obstruction, a multipass contrast-enhanced computed tomography (CT) examination to detect and stage possible pancreatic carcinoma, cholangiocarcinoma, or periductal neoplasm is usually recommended. Assessment of tumor resectability and staging can be performed by CT or a combination of CT and endoscopic ultrasound, the latter often combined with fine needle aspiration biopsy of suspected periductal tumor. In patients whose CT scan suggests hepatic hilar or central intrahepatic biliary tumor, percutaneous cholangiography and transhepatic biliary stent placement is usually followed by brushing or fluoroscopically directed fine needle aspiration biopsy for tissue diagnosis. Sonography is the imaging procedure of choice for biliary tract intervention, including cholecystostomy, guidance for percutaneous transhepatic cholangiography, and drainage of peribiliary abscesses.

Gadolinium-enhanced multidetector CT angiography of the thoracoabdominal aorta.

A 93-year-old patient with a cardiac pacemaker and biochemical renal failure presented with back pain suspicious for dissection. We performed gadolinium-enhanced thoracoabdominal multidetector CT angiography using eight-channel multidetector CT. Uniform aortic enhancement of 140 HU was sufficient to exclude aortic dissection and defined an unruptured infrarenal abdominal aortic aneurysm.

Ultrasonographic characteristics of testicular adenomatoid tumors

PURPOSE We determined the characteristics of testicular adenomatoid tumors which could distinguish these lesions from testicular malignancies. MATERIALS AND METHODS Clinical presentation and ultrasonographic findings in 3 men with testicular adenomatoid tumors were compared with those in 10 men treated for testicular malignancies. RESULTS Clinical presentation was similar for all patients. Of the 3 adenomatoid tumors 2 appeared isoechoic on ultrasound and 1 appeared normal. None of the 10 cancers appeared isoechoic or normal on ultrasound. CONCLUSIONS Small tumors that appear isoechoic on ultrasound should be biopsied through an inguinal incision with frozen section assessment rather than immediate radical orchiectomy.