CT diagnosis of acute flank pain from urolithiasis.

The use of noncontrast helical CT (NHCT) to assess patients with acute flank pain and hematuria for potential urinary tract stone disease was first reported in 1995. After several years of experience with the technique, sensitivity and specificity of NHCT has proven to be better than intravenous urography for evaluating ureteral stones. NHCT imaging findings for urinary calculi and the differential diagnosis are discussed in this article. Various extraurinary diseases found while using NHCT in searching for stone disease are addressed and illustrated. As experience with the use of NHCT has increased, clinicians have broadened the indications for this technique, which has a lower charge than standard CT, beyond the specific evaluation of urinary colic. This indication creep has increased the number of NHCT examinations ordered. It has also reduced the rate of stone positivity and increased the diagnostic yield for extraurinary disease.

Acute pancreatitis: the role of diagnostic imaging.

In the U.S., acute pancreatitis is usually caused by excessive consumption of ethanol or by biliary stone disease. Major pathologic finding and complications include fluid collections within the organ or the adjacent peripancreatic tissues, pseudocysts, pancreatic necrosis, pseudoaneurysm, and abscess formation. Radiologic imaging, including endoscopic retrograde cholangiopancreatography (ERCP), sonography, and computed tomography (CT), are important in the evaluation of acute pancreatitis and its complications. CT in particular also aids in grading the severity of acute pancreatitis and in predicting complications and mortality; however, CT correlation with Ranson's clinical prognostic factors or with other classification systems is less clear. The imaging and therapeutic aspects of acute pancreatitis are discussed and illustrated and prognostic factors are correlated.

Overview of imaging in colorectal cancer.

Accurate staging of colorectal carcinoma (CRC) at initial diagnosis is critical for proper management of this disease. Computed tomography (CT) is often used for preoperative staging and is complementary to the clinical assessment of the patient and to the use of other imaging techniques, such as endoluminal ultrasound (US). CT can identify those patients who may benefit from local radiation therapy, hepatic resection or cryoablation, or intra-arterial chemotherapy. Endoluminal US may detect patients with early disease and alter their course of therapy, especially in those with rectal carcinoma in which limited surgery might be performed. CT is generally the modality of choice for imaging the postoperative patient. CT clearly depicts the operative area, particularly after abdominoperitoneal resection, and can be used to guide percutaneous biopsy of masses. The role of magnetic resonance imaging in CRC remains to be defined. In this review, we discuss the current roles of these various imaging modalities in the management of this disease.

Interpretation of abdominal CT: analysis of errors and their causes.

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.

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

BACKGROUND: 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. METHOD: From March 1993 to April 1994, 10 consecutive patients with biopsy-proven rectal carcinomas were imaged with both endorectal MR imaging and endoscopic rectal sonography. These two studies were performed an average of 2.7 days apart in each patient. All 10 patients had surgical resection of the rectal carcinoma within days of imaging studies. TNM staging of each malignant lesion was correlated with the imaging reports. RESULT: Staging accuracy was 80% for endorectal MR imaging and 70% for endoscopic rectal sonography. With MR imaging, one T2 lesion was overstaged and one T3 lesion was understaged. With sonography, two T2 lesions were overstaged and one T3 lesion was understaged. One MR error resulted from misinterpretation. All other staging errors occurred in patients with tumor spread into, but not through, the muscularis propria or with microscopic spread through this layer. CONCLUSIONS: Endorectal MR imaging and endoscopic rectal sonography have similar accuracy for assessing depth of invasion of rectal carcinoma.

Postmortem coronary subtraction angiography.

Thorough examination of the coronary arteries is essential when performing medicolegal autopsies. In some cases, evaluation is optimized by using postmortem angiography before dissection. Unfortunately, most techniques are far too time-consuming to be readily employed by forensic pathologists. We describe a simple technique of "subtraction angiography" that provides valuable information in a timely manner in cases that can benefit from postmortem angiographic analyses. We find the technique particularly helpful in cases that have had invasive coronary artery procedures contemporaneous with death.

CT of the pediatric gastrointestinal tract.

Despite the fact that children are not small adults, some children will invariably be evaluated with adult imaging protocols. As CT gains popularity in the evaluation of the adult gastrointestinal (GI) tract, there will undoubtedly be some spillover into the pediatric age group. This pictorial essay reviews the CT appearance of some common pediatric GI disorders as common diseases may present uncommonly, both clinically and radiographically.

Computed tomography evaluation of colorectal carcinoma.

Knowledge of the extent of primary colorectal carcinoma at initial diagnosis is critical for proper management of disease. Currently, CT does not have a role in screening for colorectal carcinoma, though promising work on virtual colonoscopy is on the horizon. In patients with proven colorectal carcinoma, accurate prospective noninvasive assessment can identify those who may benefit from preoperative local radiotherapy, hepatic resection or cryoablation, or intra-arterial chemotherapy. CT should be considered complementary to the clinical assessment of colorectal carcinoma and to other modalities, such as barium enema, endorectal ultrasonography, MRI, and immunoscintigraphy. Although limited in evaluation of the primary tumor and local spread, CT has proven useful in assessing patients thought to harbor extensive local or metastatic disease. CT is generally the modality of choice for imaging the postoperative patient. The cross-sectional display of CT clearly depicts the operative bed, particularly after abdominoperineal resection. Baseline examinations should be obtained 2 to 4 months after surgery, with follow-up examinations every 6 to 9 months for 2 years, and yearly studies thereafter. CT-guided biopsies should be performed when findings suggest recurrent carcinoma.

The CT nephrogram: implications for evaluation of urinary tract disease.

The urographic nephrogram is an important indicator of underlying functional and structural renal disease. With expansions in use of cross-sectional imaging, the computed tomographic (CT) nephrogram (ie, contrast material enhancement within the renal parenchyma) has assumed a greater role in the evaluation of urinary tract disorders. Both quantitative and qualitative nephrographic abnormalities are well demonstrated by CT, including global or segmental absence or persistence of the nephrogram, slowed temporal progression, striated pattern, and rim pattern. Global absence is nearly always unilateral and is most often seen with blunt abdominal trauma with renal pedicle injury. Segmental absence is attributable to focal renal infarction, most likely due to arterial emboli. Global persistence, which is much more common than segmental persistence, may be unilateral (caused by renal artery stenosis, renal vein thrombosis, or urinary tract obstruction) or bilateral (due to systemic hypotension, intratubular obstruction, or abnormalities in tubular function). Striated nephrograms may be unilateral or bilateral and are caused by ureteric obstruction, acute pyelonephritis, contusion, renal vein thrombosis, tubular obstruction, hypotension, and autosomal recessive polycystic kidney disease. The rim pattern is most often associated with renal infarction and occasionally with acute tubular necrosis and renal vein thrombosis. Careful evaluation of the CT nephrogram is an integral part of the abdominal CT examination.

Extra-adrenal myelolipoma: report of two cases.

Myelolipomas are benign tumors composed of an admixture of mature adipose tissue and normal hematopoietic cells. The vast majority occur within the adrenal glands, but several extra-adrenal myelolipomas (EAMLs) have been reported. The typical EAML is a solitary, well-defined mass within the abdomen, most commonly in the retroperitoneal presacral area. EAMLs may produce symptoms related to their mass effect, but they are occasionally incidental findings. Most commonly, the patient is older than 40 years and has no hematologic abnormalities. It is important to distinguish EAMLs from other soft tissue tumors, in particular liposarcomas, myxoid malignant fibrous histiocytomas, and extramedullary hematopoietic tumors. We discuss two cases of EAML. The first was in the retroperitoneum of a 76-year-old woman. It is the largest EAML ever reported, measuring 26 cm x 15 cm x 11 cm. The second, a presacral mass in a 68-year-old man, was diagnosed preoperatively by percutaneous computed tomography-guided fine needle aspiration biopsy. Preoperative diagnosis facilitated surgical management in this case. We discuss the clinical, radiologic, and pathologic characteristics and the differential diagnosis of this rare entity.

Ultrasonography: usefulness in localization of the Norplant contraceptive implant system.

Norplant is a levonorgestrel-containing contraceptive system that consists of six small capsules (2.4 x 34 mm), which are placed subdermally. Owing to the relative newness of this contraceptive modality, problems with removal of the Norplant implants are just beginning to be reported; these consist primarily of inability to locate and remove all six implant capsules upon discontinuation. Ultrasonographic images of 14 women with the Norplant system in place were obtained in the axial and longitudinal planes. On axial view the capsules consisted of discrete circular individual areas of high echogenicity with prominent posterior shadowing. Capsules scanned in a longitudinal plane demonstrated echogenicity of the superior and inferior capsular walls, giving a tubular appearance. It was possible to demonstrate the depth of capsule placement, spatial relation to surrounding capsules, and orientation in relation to the skin surface. Ultrasonography therefore may provide a useful, noninvasive method for localization of nonpalpable Norplant implants, thus facilitating removal.

Esophageal squamous carcinoma.

Squamous cell carcinoma of the esophagus is a tumor with poor prognosis; it is usually in an advanced state when first diagnosed. Because a multimodal treatment approach is currently used, proper tumor staging is essential to determine whether therapy should be directed toward cure or palliation. Important prognostic features of squamous cell carcinoma include the depth of tumor infiltration into or through the esophageal wall and the presence of distant metastases. Imaging strategies should not be limited to visualization of the tumor but also should be directed toward accurate pretreatment staging. In this article, the authors review the use of barium swallow, CT scans, and endoscopic ultrasonography both alone and in combination to visualize and stage esophageal carcinoma. The strengths and limitations of each modality are also discussed.

Blunt upper abdominal trauma: evaluation by CT.

CT is the technique of choice for initial examination of hemodynamically stable patients after blunt abdominal trauma. It is highly sensitive, specific, and accurate for use in detecting the presence or absence of injury and defining its extent. Nonoperative management of many posttraumatic injuries, particularly in the liver, spleen, and kidney, is possible in part because of the diagnostic usefulness of CT. CT can be used effectively to visualize the progression of liver and spleen injuries in those patients chosen for conservative management. CT helps in treatment decisions in patients with renal injury by defining the character and extent and distinguishing minor from severe renal trauma. Posttraumatic injuries to the pancrease, bowel, and mesentery can be detected with CT. In these areas, however, signs may be subtle, and a significant injury may be missed on an initial examination.

Spontaneous perinephric hemorrhage: imaging and management.

We report on 10 patients with spontaneous perinephric hemorrhage associated with underlying disease, including renal cell carcinoma (5), angiomyolipoma (2), malignant melanoma (1), periarteritis nodosa (1) and severe portal hypertension (1). The etiology could not be identified with computerized tomography (CT) in 5 cases (50%), including 2 renal cell carcinomas, 1 angiomyolipoma, 1 periarteritis nodosa and 1 portal hypertension. Arteriography demonstrated underlying lesions in 4 of these 5 cases (80%) including the case of vasculitis. CT combined with magnetic resonance imaging is accurate for the diagnosis of spontaneous perinephric hemorrhage but the underlying pathological condition is often undetectable in the acute phase due to the perinephric blood. CT should be the first study performed if this diagnosis is suspected. Arteriography is recommended if a renal mass is not detected. If a mass is not identified with these 2 imaging studies and the patient is clinically stable, followup thin slice CT should be performed.

Positive predictive value and posttest probability of diagnosis of colonic polyp on single- and double-contrast barium enema.

The positive predictive value for a radiographic diagnosis of colonic polyp, the prevalence of polypoid disease, and posttest probability relative to patient age were studied. The positive predictive value for colonic polyp on single- and double-contrast barium enema was determined for 191 polyps found radiographically in 136 patients who also underwent colonoscopy for confirmation. Of 72 polyps seen in 54 patients on single-contrast examination, 59 were confirmed endoscopically; 110 of 119 polyps seen in 82 patients on double-contrast examination were confirmed similarly, giving positive predictive values of 82% and 92%, respectively. Positive predictive values per patient, disregarding the number of polyps present, were 87% (47/54) and 90% (74/82) for the single- and double-contrast examinations, respectively. False-positive errors were due to stool, air bubbles, haustration, and misinterpretation of an appendiceal stump. By using specificities derived from our prevalence of polypoid disease and previously reported sensitivities, we drew posttest probability curves showing that predictive values depend both on the chance of disease before the test is done and on the efficacy of the test used.

Barium enema examination: sensitivity in detecting colonic polyps and carcinomas.

We analyzed the sensitivity of the barium enema examination in 128 patients with 191 endoscopically proven colonic polyps and 12 carcinomas, relative to patient age, indications, and the type of examination used. Seventy-seven patients (60%) had rectal bleeding, and 51 (40%) patients with 87 lesions, including six carcinomas, did not. Overall roentgenographic sensitivity was 88%, with a 93% detection rate in patients less than 70 years old as compared to 76% for older patients. Sensitivity of single- and double-contrast barium enema examination was 82% and 91%, respectively. There were similar detection rates for lesions 1 cm or more in size (91% vs 95% for single- and double-contrast examinations, respectively), but double-contrast examination was slightly better at detecting smaller polyps (88%, vs 70% for single-contrast examination). Compared to colonoscopy, which has an average reported false-negative rate of 12% in detecting neoplasms, the barium enema is similarly reliable, less costly, and safer.