Stanley S. Siegelman

Prevalence of unsuspected pancreatic cysts on MDCT.

OBJECTIVE Current generation MDCT technology facilitates identification of small, nonenhancing lesions in the pancreas. The objective of this study was to determine the prevalence of findings of unsuspected pancreatic cysts on 16-MDCT in a population of adult outpatients imaged for disease unrelated to the pancreas. MATERIALS AND METHODS Contrast-enhanced MDCT scans of the abdomen were reviewed from 2,832 consecutive examinations to identify pancreatic cysts. Patients with a history of pancreatic lesions or predisposing factors for pancreatic disease or who were referred for pancreatic CT were excluded. RESULTS A total of 73 patients had pancreatic cysts, representing a prevalence of 2.6 per 100 patients (95% CI, 2.0-3.2). Cysts ranged in size from 2 to 38 mm (mean, 8.9 mm) and were solitary in 85% of cases. Analysis of demographic information showed a strong correlation between pancreatic cysts and age, with no cysts identified among patients under 40 years and a prevalence of 8.7 per 100 (95% CI, 4.6-12.9) in individuals from 80 to 89 years. After controlling for age, cysts were more common in individuals of the Asian race than all other race categories, with an odds ratio of 3.57 (95% CI, 1.05-12.13). There was no difference by sex in the prevalence of cysts (p = 0.527); however, cysts were on average 3.6 mm larger (p = 0.014) in men than women. CONCLUSION In this outpatient population, the prevalence of unsuspected pancreatic cysts identified on 16-MDCT was 2.6%. Cyst presence strongly correlated with increasing age and the Asian race.

Computed tomography of bronchiectasis

Computed tomography (CT) was performed on six patients with bronchiectasis. In two cases of advanced cystic bronchiectasis, the diagnosis was apparent on plain chest roentgenograms. In four cases, bronciectasis was initially diagnosed by CT and later confirmed by bronchography. The CT signs of bronchiectasis include air-fluid levels in distended bronchi, a linear array or cluster of cysts, dilated bronchi in the periphery of the lung, and bronchial wall thickening due to peribronchial fibrosis. Distended bronchi must be distinguished from emphysematous blebs, which generally have no definable wall thickness and no accompanying vessels. It is concluded that CT should have a role in establishing the presence and anatomic extent of bronchiectasis.

Angiographic diagnosis of mesenteric arterial vasoconstriction

Experimental mesenteric arterial vasoconstriction (MAV) is characterized by narrowings at the origins of multiple branches of the superior mesenteric artery, irregularities in intestinal branches, spasm of arcades, and impaired filling of intramural vessels. None of these findings occurred in a control group of patients without MAV. MAV may be diffuse or localized and reversible or irreversible. Reversible MAV decreases after test infusion of papaverine, and responds to therapeutic infusion of 30–60 mg of papaverine per hour for 16–24 hours. Several case studies are presented. Early diagnosis of reversible MAV is important to prevent irreversible bowel changes.

Computed tomography of the pulmonary parenchyma. Part 2: Interstitial disease

A series of patients with documented predominantly interstitial pulmonary disease was examined by routine and high-resolution computed tomography (CT) and compared to a series of twenty-one normals. Inspiratory-expiratory lung density measurements were also obtained at predetermined levels. Several basic CT signs of interstitial disease were identified: (1) finely irregular and thickened pleural surfaces; (2) irregular vascular shadows; (3) thickened and irregular bronchial walls making bronchi visible over a longer portion of their course in the lungs; (4) reticular network of lines with three patterns easily distinguishable by the size of their reticular element; (5) hazy patches of increased density of various sizes distinguishable from alveolar filling processes by the fact that vessels can still be visualized through them; and (6) nodules of various sizes. Micronodules are often associated with a small or medium-size reticular network and in most cases seem to represent points of confluence rather than isolated nodules. The hematogenous origin of some nodules can be specifically suggested when feeding vessels arc demonstrated on thin-section scans. Nodules associated with a large network of thickened septa are suggestive of lymphangitic carcinomatosis. Inspiratory-expiratory density gradients can be more useful in confirming the diagnosis of interstitial disease than absolute measurements.

CT findings in bronchiolitis obliterans organizing pneumonia (BOOP) with radiographic, clinical, and histologic correlation.

The CT features of 12 patients with bronchiolitis obliterans organizing pneumonia (BOOP) were reviewed and correlated with clinical history, histologic specimens, and chest radiography. From our series, a spectrum of CT findings of parenchymal lung involvement in BOOP emerged. Focal nodular or mass-like opacities were found in 42% (5 of 12). Areas of consolidation resembling pneumonia were seen in 33% (4 of 12). Peripheral subpleural reticular opacities were identified in 25% (3 of 12). Patchy ground glass infiltrates were seen in 8% (1 of 12). One patient demonstrated a mixed pattern consisting of nodular opacities and areas of pneumonic consolidation. In 4 of the 5 cases demonstrating the nodular form of BOOP either a feeding vessel or bronchus sign could be identified. This feature consisted of a pulmonary vessel leading to a nodular opacity or an air bronchogram entering into a nodular opacity. Correlation of the CT findings of BOOP with histologic specimens showed nodular opacities and areas of consolidation to be associated with classic pathologic features of BOOP including bronchiolar plugs of granulation tissue and surrounding organizing pneumonia. Cases demonstrating peripheral subpleural reticular opacities showed, in addition to pathologic evidence of BOOP, other features such as interstitial disease and fibrosis. From the Russell H. Morgan Department of Radiology and Radiological Sciences (L. M. Bouchardy, J. E. Kuhlman, and S. S. Siegelman), the Division of Pulmonary and Critical Care Medicine (W. C. Ball, Jr.), and the Department of Pathology (R. H. Hruban and F. B. Askin), Johns Hopkins Medical Institutions, Baltimore, MD. Address correspondence and reprint requests to Dr. J. E. Kuhlman at Department of Radiology, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287, U.S.A.

Submucosal accumulation of fat in inflammatory bowel disease: CT/pathologic correlation.

A prominent submucosal layer of decreased attenuation was demonstrated on CT in three patients with inflammatory bowel disease. On pathologic examination this zone proved to be due to extensive submucosal fat accumulation and not active inflammation. The potential significance of this finding is discussed.

Factors Influencing Quantitative CT Measurements of Solitary Pulmonary Nodules

Quantitative computed tomographic (CT) measurement of pulmonary nodules has not been widely applied despite favorable reports. Its usefulness has been questioned by some investigators. A series of experiments on six different scanners was undertaken to study the factors that affect the applicability of this technique. The type of reconstruction algorithm, the design of the CT system, the true slice thickness, and the beam kilovoltage were the most important factors identified. These factors can produce large variations in the CT numbers of pulmonary nodules, preventing direct comparison of results from scanner to scanner. Before undertaking studies of pulmonary nodules, the effect of these variables in each individual scanner should be evaluated. Despite the current lack of standardization, reliable CT number measurements using a specific kilovoltage and slice thickness should be possible on every modern scanner provided it is positionally uniform and gives a linear response to varying densities. We propose that the CT number above which a pulmonary nodule can be considered benign should be the representative CT number of a 1 cm diameter syringe filled with a hydrous calcium chloride solution of 40 mg/ml of water and scanned in air. A better understanding of the physics of lung nodule densitometry is necessary for the proper application of this technique in the management of patients with solitary pulmonary nodules.

Phase I–II study of radiolabeled antibody integrated in the treatment of primary hepatic malignancies

Abstract Primary intrahepatic malignancies have been demonstrated to contain tumor associated antigens which bind radiolabelled anti-CEA and anti-ferritin antibodies. The present study reports the toxicity and possible therapeutic efficacy of radiolabelled antibodies that were administered at 50 and 100 millicurie doses following combination radiation and chemotherapy. Three of 10 patients who entered into the study completed therapy on schedule and have had remissions of 7, 9, and 18 months; 2 of the 3 patients were alive at 1 and 2 years after treatment. Of 5 patients who were administered radioimmunoglobulin, the singular toxicity was 3 weeks of marrow hypoplasia in one patient who susequently recovered. The remaining 5 patients were at various stages of protocol treatment prior to immunoglobulin treatment. Eight of the 10 patients have had computer analysis of sequential computerized axial tomography (CAT) scans obtained during the course of therapy and at follow up examination. No major organ toxicity was noted. Clinical remissions were documented by computer analysis of the CAT scans to determine the percent of residual tumor.

Medical and Surgical Evaluation and Treatment of Adrenal Incidentalomas

INTRODUCTION Adrenal incidentalomas are detected in approximately 4% of patients undergoing high-resolution abdominal imaging studies. The majority of adrenal incidentalomas are benign, but careful evaluation of all patients is warranted to be certain that primary adrenocortical carcinoma and functional adenomas are not missed. METHODS The diagnostic approach in patients with adrenal incidentalomas should focus on two main questions: whether the lesion is malignant, and whether it is hormonally active. Radiological evaluation including noncontrast and contrast computed tomography attenuation values expressed in Hounsfield units is the best tool to differentiate between benign and malignant adrenal masses. All adrenal tumors with suspicious radiological findings, most functional tumors, and all tumors more than 4 cm in size that lack characteristic benign imaging features should be surgically excised. All patients should undergo hormonal evaluation for subclinical Cushings syndrome and pheochromocytoma, and those with hypertension should also be evaluated for hyperaldosteronism. Combined 1-mg dexamethasone suppression test, plasma metanephrines, and aldosterone/plasma renin activity measurements (if hypertensive) are reasonable initial hormonal evaluations. RESULTS Annual biochemical follow-up of most patients with adrenal incidentalomas, especially if the tumor is more than 3 cm in size, for up to 5 yr may be reasonable. Patients with adrenal masses less than 4 cm in size and a noncontrast attenuation value of more than 10 Hounsfield units should have a repeat computed tomography study in 3-6 months and then yearly for 2 yr. Adrenal tumors with indeterminate radiological features that grow to at least 0.8 cm over 3-12 months may be considered for surgical resection.

Complications of acute diverticulitis of the colon: Improved early diagnosis with computerized tomography

We have evaluated the diagnostic role of computerized tomography in 42 patients suspected clinically of having a complication of acute diverticulitis (abscess, colovesical fistula, or both). Diverticular abscesses were confirmed at operation in 10 patients. All 10 patients were diagnosed preoperatively on computerized tomography by the triad of diverticula, a segmentally thickened colon, and extravisceral fluid collection with (6 patients) or without (4 patients) associated gas. Contrast enema study suggested the presence of a diverticular abscess in only two of eight patients studied. Colovesical fistulas were confirmed in 12 patients. Eleven of 12 were diagnosed preoperatively on computerized tomography by the triad of air in the bladder, thickened colon adjacent to an area of thickened bladder, and the presence of colonic diverticula. Contrast enema examinations demonstrated the fistula in only three of eight patients studied. The remaining 20 patients proved to have uncomplicated acute diverticulitis. Findings on computerized tomography included the presence of a segmentally thickened colon with diverticula but without the findings of an abscess or a colovesical fistula. Computerized tomography correctly visualized acute diverticular complications in 21 of 22 patients and it excluded an abscess or fistula in all 20 patients with uncomplicated acute diverticulitis who were suspected of having a diverticular complication. Computerized tomography is the most sensitive and specific test for diagnosing complications of acute diverticulitis. It should be an early consideration in patients with suspected diverticular abscesses or fistulas so that appropriate therapy is not delayed.