Clinical and radiological features of respiratory syncytial virus in solid organ transplant recipients: a single-center experience.

BACKGROUND: Respiratory syncytial virus (RSV) infections range from upper respiratory illness to severe lower respiratory disease. There is no universally accepted treatment for RSV in solid organ transplant (SOT) recipients. METHODS: Retrospective review of adult SOT patients with RSV infections, between January 2007 and December 2009, in a single transplant center was performed. RESULTS: During the 3-year period, a total of 24 adults developed RSV infection, including 12 (50%) SOT recipients (5 kidneys, 4 livers, and 3 lungs). Most cases were seen in 2009 during the influenza H1N1 pandemic, likely as a result of increased testing. In 83% of the cases, the diagnosis was based on RSV antigen detection, which was also used to follow subsequent shedding (mean duration: 20.6 days). Most of the cases presented with lower respiratory disease and required hospitalization. All the patients were on at least two classes of immunosuppressive drugs. We observed a lower lymphocyte count in patients with lower respiratory tract infection. Computed tomography was superior to chest x-ray in demonstrating pulmonary disease, with the most common findings being pulmonary nodules and ground-glass opacities. Novel radiographic findings were small cavities and pleural effusions. No co-infections were documented, and no mortality could be attributed to RSV. Inhaled or oral ribavirin was administered in 67% of the cases, with variations in the treatment regimens. CONCLUSION: SOT recipients accounted for half of all adult cases of RSV at our institution. Type and length of treatment varied widely, and we cannot conclude that outcomes differed between treatments with oral or inhaled ribavirin. Current therapeutic management of RSV in SOT is empiric, and can be rather expensive and difficult, without clear evidence of effectiveness.

Intravenous stem cell dose and changes in quantitative lung fibrosis and DLCO in the AETHER trial: a pilot study.

OBJECTIVE: Our purpose was to compare quantitative CT-derived changes in lung fibrosis with pulmonary function, including DLCO, in human subjects with idiopathic pulmonary fibrosis who received an injection of one of two different intravenous doses of human bone-marrow-derived mesenchymal stem cells. PATIENTS AND METHODS: Two three-subject cohorts from the AETHER trial (Allogeneic Human Cells in subjects with Idiopathic Pulmonary Fibrosis via Intravenous Delivery) underwent high-resolution CT and clinical testing at baseline, 24 weeks, and 48 weeks after injection. Cohort 1 received 2x107 stem cells, and cohort 2 received 1x108 stem cells. CT scans were quantitatively analyzed for lung fibrosis using 510K cleared validated software. The percent predicted DLCO and other pulmonary function studies were obtained. RESULTS: The cohorts were well matched in lung fibrosis at baseline as assessed by CT scan and lung function. The mean QLF in cohort 1 increased from 13.1% at baseline to 17.1% at 48 weeks, while mean QLF in cohort 2 increased from 15.4% at baseline to 16.5% at 48 weeks. The subjects in cohort 2 progressed more slowly in whole lung fibrosis by a mean of 2.87% compared with cohort 1 (p=0.001 with adjustment of baseline covariates) during the baseline to the 48-week interval. The baseline DLCO was lower in cohort 2 than in cohort 1 (p<0.0001). Over 48 weeks of the study, cohort 2 subjects demonstrated a mean DLCO decline of only 2% compared with a decline of 17% in cohort 1 subjects (p=0.02). CONCLUSIONS: In this pilot study, the subjects receiving 1x108 stem cells demonstrated slower progression in quantitative lung fibrosis and a smaller decrease in DLCO than subjects receiving 2x107 stem cells.

Water content and NMR relaxation time gradients in the rabbit kidney.

Magnetic resonance images were made of rabbits at 1.4 tesla for the purpose of measuring the T1 relaxation times of the kidney in vivo with the animal in different states of hydration. In the normally hydrated animal, the outer cortex has a T1 of about 600 msec and there was a steep T1 gradient with an increase to about 1200 msec at the tip of the inner medulla. The relaxation time gradient was not affected by overhydration with intravenous fluid, but dehydration by withholding water for 24 hours decreased the values in the inner medulla. The T1 and T2 relaxation times and total water content were measured in vitro on tissue samples. The values for both T1 and T2 correlated with the regional renal water content.

In vivo measurements of vascular oxygen tension in tumors using MRI of a fluorinated blood substitute.

The authors measured the level of blood oxygenation in vivo in a series of rats with implanted mammary adenocarcinoma. The technique used was 19F magnetic resonance imaging of a perfluorochemical blood substitute. The method is based on the effect of oxygen on the T1 relaxation time of the fluorochemical and allows the determination of mean vascular PO2 independent of the blood volume in the tissue. The PO2 levels in the liver, lung, and spleen also were determined and were consistent with previously reported results. When the rats breathed air, the tumor PO2 levels were somewhat lower than in the other organs and were in a range typical of venous blood. When the rat was given 100% oxygen to breathe, the tumor PO2 levels increased far less than the PO2 levels of the other organs. This may indicate a greatly diminished blood flow to this particular tumor.

Design and evaluation of a radio frequency coil for nuclear magnetic resonance imaging of fluorine and protons.

A frequency-switchable, homogeneous-field rf saddle coil has been designed for imaging both protons (1H, 59.1 MHz) and fluorine (19F, 55.6 MHz) on a 1.4-T superconducting small-bore nuclear magnetic resonance imager. Frequency and impedance switching is accomplished by external capacitance and cable length changes; these operations permit imaging of both nuclei without perturbing the sample. The coil is optimized for 19F operation, yet performs better at the proton frequency than does the unswitched 19F coil. The angular distribution of the coil's wires and the use of distributed capacitors are designed to optimize field homogeneity and Q. A quantitative image of field homogeneity is presented. The coil is suitable for imaging small animals (7-cm-diam bore) and couples far better to small samples than does our standard receiver coil (15.2 cm in diameter). Images of phantoms and rats injected with a perfluorinated blood substitute are presented.

Oxygen-sensitive 19F NMR imaging of the vascular system in vivo.

The fluorine nuclear magnetic resonance spin-lattice relaxation rate (1/T1) of the perfluorochemical blood substitute perfluorotripropylamine (FTPA) is very sensitive to oxygen tension. This presents the possibility of measuring blood oxygen tension by 19F MR imaging. We obtained oxygen-sensitive 19F NMR images of the circulatory system of rats infused with emulsified FTPA. Blood oxygenation was assessed under conditions of both air- and 100% O2-breathing. T1 relaxation times were derived from MR images using a partial saturation pulse sequence. The T1 times were compared with a phantom calibration curve to calculate average blood pO2 values in the lung, liver, and spleen. The results showed marked, organ-specific increases in blood oxygen tension when the rat breathed 100% O2 instead of air.

Familial dextrocardia, divergent strabismus and situs inversus of optic disc.

A family is described in which three of four siblings have major congenital cardiac defects in association with ocular abnormalities. The eldest sibling has isolated dextrocardia and the second has total situs inversus. The fourth child has both atrial and ventricular septal defects, with pulmonary hypertension and right ventricular hypertrophy. The mother and third sibling have normal hearts but exhibit a number of ocular defects. The principal ocular anomalies demonstrated in this family are divergent strabismus, bilateral situs inversus of the optic disc, and myopia. The hereditary aspect of these multiple findings is discussed.

Thoracic lymphadenopathy in HIV patients: spectrum of disease and differential diagnosis.

To evaluate the etiology and differential features of intrathoracic lymphadenopathy (LAD) in HIV patients, chest computed tomography (CT) records from an 18-month period were reviewed to identify all HIV-positive patients with intrathoracic LAD (nodal size > or = 1 cm). Medical records were reviewed for the documentation of specific diseases causing LAD and the CD4 count at the time of imaging. Of 45 HIV-positive patients with LAD, 40 had specific diagnoses including 22 (55%) infections and 17 (43%) tumors; one patient had both (3%). Mycobacterial disease accounted for 78% of infections; five cases were secondary to bacterial pneumonia and sepsis. Of tumors, lymphoma (7 cases, 39%) was most common, followed by lung cancer, germ cell tumors, and Kaposi's sarcoma. Mean CD4 cell count in patients with tumors was much higher than in patients with infections (314 vs. 62, p < .01). Patients with tumors were somewhat more likely than patients with infections to demonstrate axillary adenopathy (29 vs. 5%, p = .068). Cavitary disease was only observed in patients with infections (27%, p < .03). CT and clinical findings may help direct the differential diagnosis of LAD in AIDS, and promote expedient definitive diagnosis and therapy.

Metachronous primary carcinomas of the lung in an HIV-infected patient.

Studies have suggested that human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients have an increased risk of developing primary lung cancer, with a poor prognosis. We report a 59-year-old HIV-seropositive man who developed two metachronous primary bronchogenic carcinomas with different histologic features. The initial tumor was cured after early diagnosis and resection, with subsequent development of a contralateral tumor 6 years later. The case emphasizes that early diagnosis and treatment of lung cancer in HIV/AIDS patients should be sought as they may improve their short-term prognosis. However, because of their immunocompromised state, extended survival is still limited by a higher likelihood of developing subsequent malignancies.

Cavitary lung disease in AIDS: etiologies and correlation with immune status.

To investigate the etiology and differential features of cavitary lung disease in patients with acquired immune deficiency syndrome (AIDS), chest computed tomography (CT) records from a 2-year period were reviewed to identify all human immunodeficiency virus (HIV)-positive patients with cavitary lung disease. Medical records were reviewed for the documentation of specific causes of lung cavitation and the CD4 count at the time of imaging. Of 25 HIV-positive patients with cavitary lung disease, 20 had specific diagnoses. Infection was the etiology in all the cases. Polymicrobial infection was found in 17 patients (85%) and unimicrobial in 3 (15%). Seventeen patients (85%) had bacterial organisms, 10 of whom had other pathogens as well. Mycobacteria were isolated in 8 patients (40%), fungi in 3 (15%), cytomegalovirus (CMV) in 3 (15%), and Pneumocystis carinii pneumonia (PCP) in 1 (5%). Mediastinal or hilar lymphadenopathy and additional noncavitary ill-defined nodular opacities were found more frequently in patients with mycobacterial pathogens. Mean CD4 count in patients with cavitary disease because of bacterial pathogens alone was significantly higher than in patients with nonbacterial pathogens (alone or combined with bacterial pathogens) (203 vs. 42, p < 0.05). Four patients expired during the diagnostic hospital admission; 2 of them had pulmonary cavitary disease associated with Nocardia asteroides. Cavitary lung disease in patients with AIDS undergoing chest CT should be assumed infectious and is generally polymicrobial.

Imaging of blunt aortic and great vessel trauma.

The thoracic aorta and great vessels are at risk of injury by both blunt and penetrating trauma. High-speed deceleration injury, predominately caused by motor vehicle accidents, is the primary cause of blunt traumatic aortic injury (TAI). Though largely fatal if untreated, these injuries are amenable to surgical repair if appropriately diagnosed. Algorithms for both diagnosis and treatment of TAI have undergone changes in recent years. Radiologic imaging plays a key role in the evaluation of TAI, and this review focuses on the relative roles of chest radiography, computed tomography (CT) (particularly helical CT), and aortography in the diagnostic algorithm for TAI. Other aortic imaging methods have been used in the setting of TAI, such as transesophageal echocardiography, magnetic resonance imaging, and intravascular ultrasound; although these techniques may play a complementary role in TAI evaluation, they are unlikely to have as significant an impact on routine radiologic practice as will CT.

Radiographic findings and patterns in multidrug-resistant tuberculosis.

Multidrug-resistant tuberculosis (MDR TB) is prevalent in urban areas with large HIV-positive populations. We retrospectively evaluated the chest radiographs of MDR TB patients at presentation and compared them to patients with drug-sensitive tuberculosis (DS TB). Although the overall radiographic findings and patterns of MDR TB and DS TB were similar, there were significant differences among the MDR TB patients depending on how MDR TB was acquired. Patients who developed MDR TB during an outbreak showed noncavitary consolidations, pleural effusions, and a primary radiographic pattern (70%). On the other hand, patients who acquired MDR TB due to noncompliance with antituberculous therapy often had cavitary consolidations (50%) and generally demonstrated a postprimary radiographic pattern. Cavitation occurred equally in patients with MDR TB who are HIV positive regardless of CD4 cell count. Chest radiographic findings and patterns in MDR TB are most accurately interpreted in conjunction with clinical history, specifically prior TB treatment. Nevertheless, approximately one-third of patients did not show the "expected" radiographic pattern.

Pictorial essay: thoracic cardiovascular complications of acquired immunodeficiency syndrome.

Patients with acquired immunodeficiency syndrome frequently develop complications of cardiac, pericardial, and thoracic vascular origin. The purpose of this pictorial essay is to review the most common etiologic and diagnostic imaging findings of these diseases. Patients with acquired immunodeficiency syndrome often demonstrate enlargement of the cardiac silhouette on the chest radiograph. While the cause of this finding may be clinically evident, the authors share cases in which chest computed tomography, echocardiography, and nuclear medicine studies better reveal the nature of underlying cardiac and pericardial abnormalities. Thoracic vascular complications, including pulmonary hypertension, pulmonary thromboembolism, and the sequelae of indwelling venous catheters, are also addressed.

Atrial thrombosis as a late complication of cardiac surgery computed tomography appearance.

We present two cases of large atrial thrombi diagnosed many years after cardiac surgery. In both cases, CT showed homogeneous non-enhancing masses. In one case the mass was immediately adjacent to an area of surgical repair; neither thrombus was in the atrial appendage, a more common location for thrombosis. The combination of appropriate clinical history and CT appearance should permit recognition of delayed postoperative intracardiac thrombosis.

Pulmonary arteriovenous fistula within a pulmonary cyst - evaluation with CT pulmonary angiography.

Pulmonary arteriovenous malformations (PAVMs) are abnormal direct communications between pulmonary arteries and pulmonary veins. These abnormal communications result in an anatomical right-to-left shunt that reduces the arterial oxygen saturation and may cause hypoxaemia and dyspnoea. Although PAVMs frequently remain undiagnosed, they are associated with severe morbidity in the form of ischaemic strokes and brain abscesses. We report a case of incidental CT angiography depiction of a PAVM within a pulmonary cyst. To the best of our knowledge, no such case has been described previously. On the basis of its appearance and lack of typical clinical features of hereditary haemorrhagic telangiectasia (HHT), we suggest that this PAVM actually represents an acquired fistula from a previously unrecognised focal pulmonary insult, such as trauma or infection, that simultaneously evolved into a pulmonary arteriovenous fistula (PAVF) within a traumatic pulmonary cyst or pneumatocele.

Renal vein thrombosis in utero: duplex sonography in diagnosis and follow-up.

Neonatal renal vein thrombosis (RVT) is a well-described entity which is traditionally associated with a variety of perinatal stresses. Prenatal RVT is much less commonly detected. We describe a case in which a screening obstetrical ultrasonogram detected a fetal renal abnormality which was incorrectly interpreted as a suspected neoplasm of the fetal kidney. Ultrasonographic examinations during the first week of life confirmed the diagnosis of RVT, and both gray-scale and Doppler techniques were used to follow the resolution of the thrombosis and the fate of the kidney.