Computed tomography appearance of a right cervical aortic arch.

The clinical diagnosis of cervical aortic arch rests on the detection of a pulsatile mass in the supraclavicular fossa. Unfortunately, clinical differentiation of a cervical arch from an aneurysm of the great vessels can be difficult. Dynamic computed tomography (CT) can aid in this differentiation and avert the need for angiography.

Enhanced pancreatic CT imaging utilizing a geometric magnification technique.

Computed tomography (CT) using a geometric magnification technique was found to improve spatial resolution in phantom studies when compared with conventional third-generation geometry images. The clinical feasibility of using geometric magnification, small focal spot size, and dynamic contrast enhancement was studied in 143 patients referred to CT for clinically suspected pancreatic disease. This population included 46 patients with a normal pancreas and 36 patients subsequently proven to have primary pancreatic carcinoma. Using this new technique in conjunction with dynamic contrast enhancement resulted in high quality pancreatic images. Despite the limitations in tube current associated with a small focal spot size and low total heat capacity of the system, clinical imaging was not adversely affected. Use of the geometric magnification technique is recommended in departments where it is technically feasible.

Noninvasive imaging of the gastrointestinal tract.

Numerous radiographic and scintigraphic imaging modalities are now available for evaluating the gastrointestinal system. With a well-formulated plan based on patient history, physical examination, and laboratory values, together with knowledge of patient preparation techniques and consultation, an efficient customized approach to gastrointestinal disease can be accomplished.

Imaging of the liver, biliary tract, and pancreas.

The interaction between the various noninvasive and invasive imaging modalities used to evaluate the liver, biliary tract, and pancreas is demonstrated in this article. By understanding this interaction and correlating noninvasive studies, the clinician will avoid diagnostic redundancy and the need for invasive testing may be reduced.

Pancreatic imaging.

In this article, the pancreas is evaluated with regard to the controversies surrounding this organ from a clinical standpoint, and an approach to imaging modalities is examined. The roles of computed tomography, ultrasound, endoscopic retrograde cholangiopancreatography, and magnetic resonance imaging are put into proper perspective.

Imaging approach to the suspected renal mass.

The authors present their algorithmic approach to the detection, characterization, and staging of renal masses. Based on classification of urographic findings, the patient may be triaged to the appropriate cross-sectional or invasive imaging modality that will result in the most cost-effective management.

Hepatic imaging: current status.

The radiologist needs to be aware of the varied appearance of hepatic mass lesions and be prepared to recommend the most cost-effective imaging approach. In this article, the authors discuss their hepatic imaging experience, common pitfalls, and current recommendations.

Controversies in the radiologic diagnosis of pelvic malignancies.

Although vast differences exist among the many pelvic malignancies, several unifying concepts emerge from this discussion. First, there is a different role for diagnostic imaging for each type of pelvic malignancy. The radiologist should be aware that although the radiographic findings may be similar, the clinical impact varies greatly with a particular tumor. Second, although clinical staging is notoriously inaccurate, nevertheless diagnostic imaging techniques only improve upon but do not replace it because of false-positive and false-negative results. Third, because of the high false-negative rates of most of the modalities in use, negative studies do not in fact rule out the presence of disease. A surgical procedure may still be needed. Finally, several new techniques, including MRI and transrectal or transurethral ultrasound, may improve the accuracy rates. These developments will probably further enliven the controversies surrounding the radiologic evaluation of pelvic malignancies.

Deionised water as an adjunct to surgery for the treatment of canine cutaneous mast cell tumours.

Medical records of 55 dogs with a diagnosis of cutaneous mast cell tumour were reviewed. Twenty-seven of the dogs were treated with surgery plus deionized water and the remaining 28 with surgery alone. A survival analysis was performed to determine whether deionized water, as an adjunct to surgery for cutaneous mast cell tumour, affected survival time or time to tumour recurrence. Dogs in which mast cell tumour recurred had a significantly shorter survival time compared with dogs with no recurrence (P = 0.05), regardless of the method of treatment. A significant negative association between tumour recurrence and method of treatment (P = 0.0097) and clinical stage (P = 0.0223) was observed. Dogs treated with surgery and deionized water had a significantly shorter time to recurrence of their mast cell tumour (P = 0.0113). Based on these results, deionized water does not appear to be beneficial in prolonging survival time or time to tumour recurrence for dogs with cutaneous mast cell tumours.

Sonographic features of uterine leiomyomas: analysis of 41 proven cases.

The relative frequencies of the different sonographic features and patterns of uterine leiomyomas have been examined by prospective and retrospective analyses of the sonograms in 41 proven cases. The original sonographic reports correctly predicted the presence of myomas in 27/45 studies (sensitivity = 60 per cent). Retrospective analyses of the sonograms revealed abnormalities in 32/41 patients (sensitivity = 78 per cent). Most myomatous uteri had two or more sonographic abnormalities, most frequently uterine contour irregularity (76 per cent), altered echo texture (68 per cent) and/or enlargement (66 per cent). Minimal contour irregularity at the interface between the uterus and the bladder deserves emphasis as a subtle diagnostic sign of leiomyoma. Careful attention to the uterus in examining a patient referred for an adnexal mass should improve the diagnostic accuracy of myoma detection by sonography.

Endoscopic retrograde computed tomography of the pancreas.

Endoscopic retrograde cholangiopancreatography (ERCP) and computed tomography (CT) are well established diagnostic studies for pancreatic evaluation. We conducted a study to determine whether performing these examinations in tandem increased diagnostic accuracy. Patients undergoing ERCP with successful cannulation of the pancreatic duct and who could be placed in the gantry of our CT scanner within 30 min were included in the study. The combined examination, or endoscopic retrograde computed tomography of the pancreas (ERCTP), provided additional useful information in several types of patients including those who had intrapancreatic air without clinical abscess, those with apparent total obstruction of the pancreatic duct on ERCP, and those who were post partial pancreatectomy and were being considered for additional surgery. No additional useful information was provided in patients with a normal ERCP or in routine cases of pancreatitis.

Hepatobiliary scintigraphy and sonography in early biliary obstruction.

The authors examined 139 patients thought to have early, partial, or intermittent biliary obstruction, using sonography, hepatobiliary scintigraphy, and in selected cases contrast cholangiography. Of 125 patients with a well-established final diagnosis, sonography and scintigraphy disagreed in 29 (23%). Scintigraphy revealed early or low-grade obstruction in 13 patients who had no evidence of dilated ductules, while 7 patients with dilatation from prior stone passage or biliary surgery showed normal clearance. The authors conclude that in a preselected population in whom early or low-grade biliary obstruction may be present, disagreement between sonography and scintigraphy is not rare, and the absence of sonographically detectable dilatation does not exclude obstruction.

Natural history of neonatal periventricular/intraventricular hemorrhage and its complications: sonographic observations.

Cranial sonography is an established procedure for the detection of neonatal intracranial hemorrhage. A 3 year experience in imaging such infants is reviewed. Representative examples are presented to comprehensively illustrate the spectrum of sonographic appearances of intracranial hemorrhage and its complications from the initial hemorrhage to resolution. Diagnostic problems in the initial staging of the grade of hemorrhage and in evaluating subsequent ventricular changes are addressed.

Postcholecystectomy syndrome: evaluation using biliary scintigraphy and endoscopic retrograde cholangiopancreatography.

We prospectively studied 30 patients with postcholecystectomy syndrome to determine the efficacy of biliary scintigraphy in the detection of stenosis of the sphincter of Oddi. All patients underwent endoscopic retrograde cholangiopancreatography (ERCP). Biliary scintigraphy disclosed stenosis of the sphincter by agreement with the ERCP or surgical findings in nine (90%) of ten patients and in eight (100%) of eight patients with biliary obstruction from other causes. Retention of activity at 2 hours in visually prominent ducts was the best predictor of abnormal biliary drainage. Biliary scintigraphy is a useful, noninvasive screening test for the detection of postcholecystectomy biliary obstruction.

Prevesical hematoma: a complication of prostatic biopsy.

Pelvic hematomas following prostatic biopsy are rare. We describe 2 cases of hematomas occurring in the prevesical space (space of Retzius) following transrectal biopsy. Computed tomography (CT) was useful in defining the extent of the hematoma and showing density changes related to the age and suppuration of the hematoma. While cystography has been used to diagnose prevesical hematomas, CT better assesses the size of the hematoma and changes that may occur over time.

Extensive venous thrombosis and hind-limb edema associated with adrenocortical carcinoma in a dog.

A 10-year-old, spayed female, mixed-breed dog was referred for evaluation of bilateral hindlimb edema and weakness. Abdominal ultrasonography showed increased echogenicity of the lumen of the caudal vena cava from the level of the urinary bladder to the level of the cranial pole of the right kidney. Bilateral saphenous venograms displayed numerous filling defects in the caudal vena cava, right external iliac vein, right femoral vein, and the right common iliac vein. Extensive venous thrombosis was diagnosed, and the animal was euthanized. Necropsy confirmed the presence of venous thrombosis and revealed a right adrenocortical carcinoma that had invaded the caudal vena cava.

Wilms tumor: ultrasonic features, pathologic correlation, and diagnostic pitfalls.

The gray-scale ultrasonic features of Wilms tumor are reported with pathologic comparison. The most consistent ultrasonic features are large size, sharp margination, and echogenic heterogeneity. The frequently observed anechoic areas correlated with hemorrhage and necrosis. A rare case of mesoblastic nephroma is included for comparison. Pitfalls in diagnosis are discussed.

Perirenal cobwebs: the expanding CT differential diagnosis.

Although initially described as representing collateral venous structures, perirenal cobwebs may be due to a variety of benign and malignant conditions. Six representative cases illustrating the broad differential diagnosis are presented.

Renal cell carcinoma: dynamic thin-section CT assessment of vascular invasion and tumor vascularity.

Dynamic thin-section computed tomography (CT) was used to evaluate renal cell carcinoma in 80 patients. The lesion was correctly staged with CT in 90% of patients. With use of the dynamic technique, the ipsilateral renal vein was depicted in 99% of patients. Extension of the tumor to the renal vein or the inferior vena cava was correctly detected in 18 of 19 patients. Actual depiction of tumor thrombus was a far more accurate indicator of renal vein invasion than was the identification of isolated renal vein enlargement. Dynamic thin-section CT of the kidney should be considered the routine method for comparison studies with other newer cross-sectional techniques in the evaluation of renal cell carcinoma.

Sonography of adrenal pheochromocytomas.

The sonographic features of eight surgically confirmed pheochromocytomas are described and correlated with pathologic findings. The purely solid masses were homogeneous or heterogeneous sonographically. Pathologic examination of the gross specimen provided explanations for the variety of sonographic findings. Two tumors had large cystic components due to old blood. Other hypoechoic areas corresponded to necrosis pathologically. Hyperechoic areas represented hemorrhage. Generally, pheochromocytomas are quite large, sharply marginated, and usually have a significant solid component with or without central necrosis or hemorrhage. Recognition of these features should facilitate their identification on sonography.