Sanjeev Bhalla

A Pattern-based Approach to Assessment of Delayed Enhancement in Nonischemic Cardiomyopathy at MR Imaging

Although delayed contrast material-enhanced cardiac magnetic resonance (MR) imaging has traditionally been used to evaluate ischemic disease and myocardial viability, it is increasingly being used in the evaluation of nonischemic cardiomyopathies. Unlike myocardial infarction, which demonstrates subendocardial or transmural delayed contrast enhancement in a vascular distribution, nonischemic cardiomyopathies demonstrate enhancement that is not limited to a vascular territory. In combination with other cardiac MR imaging features, the location (subendocardial, transmural, subepicardial, or mesocardial) and pattern (patchy or diffuse) of abnormal delayed myocardial enhancement allow differentiation between ischemic (infarct-related) and nonischemic cardiomyopathies and, in cases of nonischemic cardiomyopathy, narrowing of the differential diagnosis. With use of a structured approach, delayed contrast-enhanced cardiac MR imaging can be helpful in the early detection and appropriate treatment of nonischemic cardiomyopathies.

CT Features of Esophageal Emergencies

Esophageal emergencies-primarily, perforation and conditions with the potential to progress to perforation-result in significant morbidity and mortality if they are not recognized and treated promptly. The spectrum of esophageal emergencies includes esophagitis, foreign body impaction, and traumatic esophageal injury. Because there is considerable variability in the clinical manifestations of emergent esophageal conditions, computed tomography (CT) may play both primary and complementary roles in their diagnosis and evaluation. An awareness of the CT findings associated with the spectrum of acute esophageal disease facilitates the accurate and prompt diagnosis of esophageal emergencies and thereby contributes to a more successful outcome.

MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.

Purpose The purpose of this study was to determine the lobar distribution and associated radiologic/clinical findings of partial anomalous pulmonary venous return (PAPVR) in the adult population using multidetector computed tomography (MDCT). Materials and Methods The radiology information database was queried for patients with PAPVR diagnosed on chest computed tomography. Forty-seven cases of PAPVR were retrospectively identified from 45,538 contrast-enhanced chest computed tomography examinations performed over an 8-year period. Diagnostic findings were confirmed via consensus review by 2 cardiothoracic radiologists. Medical charts were evaluated for ancillary radiographic data, cardiopulmonary signs and symptoms, and subsequent surgical interventions. Results Calculated disease prevalence was 0.1%, with mean patient age of 58 years and a 58% female predominance. PAPVR was observed with 47% frequency in the left upper lobe, 38% right upper lobe (RUL), 13% right lower lobe, and 2% left lower lobe. Among cases of RUL PAPVR, 42% were associated with sinus venosus atrial septal defect (ASD). Other reported anomalies were right-sided volume overload (47%), isolated upper lobe PAPVR (29% left and 5% right), bilateral PAPVR (4%), scimitar syndrome (13%), persistent left superior vena cava (9%), and azygos continuation of the inferior vena cava (4%). Reported cardiopulmonary signs/symptoms and imaging modalities other than MDCT were neither sensitive nor specific for PAPVR. Surgical repair was performed in 21% of cases and included ASD patching, intracardiac baffle, anomalous vein anastomosis, systemic vein translocation, and Warden procedure. Conclusions This represents the largest and only consecutive retrospective study of PAPVR in adults to date. Left upper lobe PAPVR was the most frequent location detected on MDCT, whereas RUL PAPVR was slightly less common and moderately associated with sinus venosus ASD. Utilization of contrast-enhanced studies and MDCT technology has enabled improved detection and characterization of PAPVR for early diagnosis and/or intervention.

Diagnosing pulmonary embolism in pregnancy using computed-tomographic angiography or ventilation-perfusion.

OBJECTIVE: To estimate the rate of nondiagnosis for patients who initially undergo computed-tomographic angiography compared with those who undergo ventilation–perfusion imaging to diagnose pulmonary embolism in pregnancy. METHODS: This was a retrospective cohort study of all women consecutively evaluated from 2001–2006 for clinical suspicion of pulmonary embolism who were pregnant or 6 weeks postpartum and underwent at least computed-tomographic angiography or ventilation–perfusion scan. Charts were abstracted for history, clinical presentation, examination, imaging, and pregnancy and maternal outcomes. Women who underwent computed-tomographic angiography for initial diagnosis were compared with women who underwent ventilation–perfusion. Primary outcome was defined as a nondiagnostic study: nondiagnostic for pulmonary embolism in the computed-tomographic angiography group, or “low or intermediate probability” in the ventilation–perfusion group. Univariable, bivariable, and multivariable analyses were performed. RESULTS: Of 304 women with a clinical suspicion of pulmonary embolism, initial diagnosis was sought by computed-tomographic angiography in 108 (35.1%) and by ventilation–perfusion in 196 (64.9%) women. Women who underwent computed-tomographic angiography tended to have a slightly higher rate of nondiagnostic study (17.0% compared with 13.2%, P=.38). Examining the subgroup of women with a normal chest X-ray, computed-tomographic angiography was much more likely to yield a nondiagnostic result than ventilation–perfusion, even after adjusting for relevant confounding effects (30.0% compared with 5.6%, adjusted odds ratio 5.4, 95% confidence interval 1.4–20.1, P<.01). CONCLUSION: Pregnant or postpartum women with clinical suspicion of a pulmonary embolism and a normal chest X-ray are more likely to have a diagnostic study from a ventilation–perfusion scan compared with a computed-tomographic angiography. Evidence supports computed-tomographic angiography as a better initial test than ventilation–perfusion in patients with an abnormal chest X-ray. LEVEL OF EVIDENCE: II

AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE IS ASSOCIATED WITH AN INCREASED PREVALENCE OF RADIOGRAPHIC BRONCHIECTASIS

BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is a common disease with several known extrarenal manifestations, although no known pulmonary features. The formation of renal cysts in ADPKD has been attributed to dysfunction of primary cilia and the primary cilia-related proteins polycystin-1 (in 85% of cases) and polycystin-2 in renal epithelial cells. The goals of this study were to characterize the normal expression of polycystin-1 in the motile cilia of airway epithelial cells and to evaluate lung structure in ADPKD patients. METHODS Airway epithelium from non-ADPKD patients was immunostained to localize polycystin-1 expression, and lung tissue from ADPKD patients was examined for pathologic changes. CT scans from ADPKD patients (n = 95) and a control group of non-ADPKD chronic kidney disease patients (n = 95) were retrospectively reviewed for the presence of bronchiectasis using defined criteria. RESULTS Immunostaining revealed polycystin-1 expression in the motile cilia of non-ADPKD airway epithelial cells. Lung tissue from one of five available ADPKD patient autopsies revealed histologic changes of bronchiectasis. Review of CT scans revealed a threefold-increased prevalence of bronchiectasis in the ADPKD group compared to the control group (37% vs 13%, p = 0.002). CONCLUSIONS ADPKD patients demonstrate an increased prevalence of radiographic bronchiectasis, a previously unrecognized manifestation of the disease. This association suggests that patients with primary cilia-associated diseases may be at risk for airway disease.

Aortoenteric Fistulas: CT Features and Potential Mimics

Prompt diagnosis of aortoenteric fistulas is imperative for patient survival. The clinical signs of aortoenteric fistula include hematemesis, melena, sepsis, and abdominal pain, but the condition also may be clinically occult. Because clinical signs may not be present or may not be sufficiently specific, imaging is most often necessary to achieve an accurate diagnosis. Although no single imaging modality demonstrates the condition with sufficient sensitivity and specificity, computed tomography (CT), owing to its widespread availability and high efficiency, has become the imaging modality of choice for evaluations in the emergency setting. CT has widely variable sensitivity (40%-90%) and specificity (33%-100%) for the diagnosis of aortoenteric fistulas. To use this modality effectively for the initial diagnostic examination, radiologists must be familiar with the spectrum of CT appearances. Mimics of aortoenteric fistulas include retroperitoneal fibrosis, infected aortic aneurysm, infectious aortitis, and perigraft infection without fistulization. Differentiation is aided by the observation of ectopic gas, loss of the normal fat plane, extravasation of aortic contrast material into the enteric lumen, or leakage of enteric contrast material into the paraprosthetic space; these features are highly suggestive of aortoenteric fistula in a patient with bleeding in the gastrointestinal tract.

CT of acute abdominal aortic disorders

Aortic aneurysm rupture, aortic dissection, PAU, acute aortic occlusion, traumatic aortic injury, and aortic fistula represent acute abdominal aortic conditions. Because of its speed and proximity to the emergency department, helical CT is the imaging test of choice for these conditions. MR imaging also plays an important role in the imaging of aortic dissection and PAU, particularly when the patient is unable to receive intravenous contrast material. In this era of MDCT, conventional angiography is used as a secondary diagnostic tool to clarify equivocal findings on cross-sectional imaging. Ultrasound is helpful when CT is not readily available and the patient is unable or too unstable to undergo MR imaging.

Asbestos-Related Lung Disease: A Pictorial Review

Asbestos exposure can lead to a variety of adverse effects in the thorax. Although currently in the western world, levels of exposure are kept in check by strict regulations, history of previous asbestos exposure continues to have an effect on many, owing to the latent nature of the pathophysiological response of the body to the inhaled fibers. The adverse effects of asbestos generally fall under 3 categories: pleural disease, lung parenchymal disease, and neoplastic disease. Effects on the pleura include pleural effusions, plaques, and diffuse pleural thickening. In the parenchyma, rounded atelectasis, fibrotic bands, and asbestosis are observed. Differentiating asbestosis from other forms of interstitial lung diseases, such as idiopathic pulmonary fibrosis, usual interstitial pneumonia, smoking-related lung disease, and mixed interstitial lung diseases, is important because the prognosis, course of disease, and management of the patient should be tailored based on the specific etiology of the disease. In this review, imaging findings specific to asbestosis are discussed. Finally, exposure to asbestos can lead to neoplastic disease such as pleural mesothelioma, peritoneal mesothelioma, and bronchogenic carcinoma. The purpose of this article is to review the effects of asbestos exposure in the thorax, pathophysiology of these responses, and disease course. Particular emphasis is placed on the radiographic appearance of the disease, discussion of various imaging modalities and their utility, and the role of imaging in the management of patients with previous asbestos exposure and asbestos-related pulmonary disease.

CT of pregnancy-related complications

During pregnancy, the risk of radiation exposure to the fetus is increased so that more than the usual benefit is necessary to justify computed tomography (CT; or other radiation exposure) than in non-pregnant patients. In the setting of a life-threatening illness, CT may be indicated to assess for potentially fatal complications such as hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. After delivery, patients rarely develop serious problems requiring radiologic evaluation. When indicated, however, CT may be invaluable in making the diagnosis or determining the severity of peri- and post-partum complications, including uterine perforation, hemorrhage, endometritis, thrombophlebitis, and abscess formation. At times, CT may be the first to uncover conditions, such as post-partum cardiomyopathy, and heart failure, which are usually diagnosed by other modalities but may explain the symptoms for which the study was ordered. In some centers, CT pulmonary angiography represents the standard of care to diagnose pulmonary thromboembolism. In this article, we illustrate the spectrum of peri-partum and post-partum complications on CT to familiarize the radiologist with the CT features of these potentially life-threatening pregnancy-related complications.

Pediatric Cardiac Tumors: Clinical and Imaging Features

Cardiac tumors in children are rare, are more commonly benign, and differ in types when compared with those in adults. Rhabdomyoma, teratoma, and fibroma are the most common cardiac tumors in fetuses and neonates. In infants and children, the most common cardiac tumors are rhabdomyoma and fibroma, which are benign primary cardiac tumors, whereas in adults, thrombus is the most common cardiac mass and myxoma is the most common primary cardiac tumor. Sarcomas are the most common primary malignant cardiac tumors in both children and adults. Metastatic cardiac tumors are less common in children than in adults and include sarcoma, lymphoma, testicular cancer, and Wilms tumor. Patients with cardiac tumors can be asymptomatic or may present with murmur, arrhythmia, heart failure, or sudden death. Echocardiography is the primary modality for initial evaluation of symptomatic patients. Cardiac magnetic resonance imaging provides further characterization of cardiac masses and tumors for diagnostic purposes and can be used to assess cardiac and extracardiac involvement for treatment planning. Treatment varies from conservative management or surgical resection to transplantation, depending on the diagnosis and the patients symptoms. Rhabdomyoma typically regresses spontaneously during early childhood and does not require surgical intervention if asymptomatic. However, fibroma is generally resected because it does not regress. An understanding of the types of cardiac tumors that occur in infants and children, their clinical implications and associations, and their imaging appearances will facilitate patient management.