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.

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.

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.

Pulmonary Embolism in Pregnant Patients:A Survey of Practices and Policies for CT Pulmonary Angiography

OBJECTIVE

We surveyed the practices and policies of the radiology departments of the Society of Thoracic Radiology members regarding the use of CT pulmonary angiography in pregnant patients suspected of having pulmonary embolism.

MATERIALS AND METHODS

Surveys were mailed electronically to the 403 members of the Society of Thoracic Radiology (403 addresses). Respondents were asked to send one response from each institution or department. Information gathered included use of CT angiography in relation to ventilation-perfusion imaging in pregnant patients, written policies, informed consent procedures, and modifications of standard protocols for dose reduction.

RESULTS

Fifty-seven members responded; 43 (75%) reported that they perform CT angiography in pregnant patients suspected of having pulmonary embolism. Of the 43 respondents who perform CT angiography in pregnant patients, 23 (53%) generally perform CT angiography as the initial study rather than ventilation-perfusion scanning, 26 (60%) require informed consent from the patient, seven (16%) have a written policy concerning CT angiography in pregnant patients, and 17 (40%) modify standard imaging protocols for pregnant patients. The most common modification for dose reduction is decreasing the scanning area along the z-axis.

CONCLUSION

Most respondents perform CT angiography in pregnant patients suspected of having pulmonary embolism, but their policies and practices vary considerably.

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.

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.

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.

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.

Pulmonary tuberculosis in AIDS patients: transient chest radiographic worsening after initiation of antiretroviral therapy

OBJECTIVE

Immune function and inflammatory responses often increase in AIDS patients who receive antiretroviral therapy. We evaluated the occurrence and nature of transient worsening on chest radiographs in AIDS patients with tuberculosis after initiation of antiretroviral therapy and compared these findings with chest radiographs of patients undergoing antituberculous therapy alone.

MATERIALS AND METHODS

A retrospective review of sequential chest radiographs was performed of 87 patients undergoing therapy for pulmonary tuberculosis: AIDS patients receiving antiretroviral therapy (n = 31), HIV-positive patients not receiving antiretroviral therapy (n = 26), and HIV-negative patients (n = 30). Pulmonary consolidations, thoracic lymphadenopathy, and pleural effusions were evaluated for worsening, stability, or improvement. Patients with concurrent pulmonary infections were excluded.

RESULTS

Transient worsening on radiography was observed in 14 (45%) of 31 AIDS patients receiving antiretroviral therapy, including seven patients (23%) who showed severe worsening. Of 56 patients in the other two groups, 11 (20%) showed worsening (p = 0.023), two of whom showed severe worsening (p = 0.009). Worsening was first noted between 1 and 5 weeks after initiation of antiretroviral therapy, with improvement occurring between 2 weeks and 3 months later. Four patients with severe worsening converted their tuberculin purified protein derivative responses from anergic to positive after antiretroviral treatment.

CONCLUSION

Transient worsening is frequently seen on chest radiography in AIDS patients with tuberculosis who subsequently undergo antiretroviral therapy. This phenomenon may be related to improved immune function.

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.

Direct versus indirect signs of traumatic aortic injury revealed by helical CT: performance characteristics and interobserver agreement

OBJECTIVE

The purpose of this study was to evaluate the relative value of and interobserver agreement on direct versus indirect (hematoma) signs of traumatic aortic injury using helical CT.

MATERIALS AND METHODS

From April 1994 through January 1997, 40 patients who were suspected to have traumatic aortic injury and who underwent contrast-enhanced helical CT had subsequent proof or exclusion of aortic injury. All available CT scans of these patients were combined with CT scans of 13 randomly chosen patients that had been initially interpreted as negative, and clinical follow-up showed no evidence of aortic injury. Two emergency radiologists and a nonemergency radiologist who were unaware of clinical outcome performed independent review of these cases to evaluate for mediastinal hematoma, periaortic hematoma, and direct signs of aortic injury.

RESULTS

Direct signs of injury were seen on helical CT by both emergency radiologists in all 17 cases of aortic injury with no false-positive interpretations. The nonemergency radiologist failed to observe subtle direct signs in two cases of aortic injury, but patient management would not have been adversely affected. All observers had more false-negative interpretations for both mediastinal hematoma and periaortic hematoma than for direct signs. Interobserver agreement was higher for direct signs (kappa = .93) than for either mediastinal hematoma (kappa = .65) or periaortic hematoma (kappa = .71).

CONCLUSION

In this study, helical CT revealed direct signs of traumatic aortic injury that were more accurate and more often observed than were indirect signs. Emphasis on direct signs should improve confidence in using helical CT to evaluate traumatic aortic injury.

Detection of suspected malignant patterns in three-dimensional magnetic resonance breast images

In this article, a Boolean Neural Network (BNN) is used for the detection of suspected malignant regions in 3D breast magnetic resonance (MR) images. The BNN is characterized by fast learning and classification, guaranteed convergence, and simple, integer weight calculations. The BNN learning algorithm is incremental, which allows the addition and deletion of training patterns without unlearning those already learned. The incremental learning algorithm automatically reduces the training set and trains the network only with those examples estimated to be useful. The architecture is suitable for parallel hardware implementation using available Very Large Scale Integration (VLSI) technology. The BNN was trained by using a set of malignant, benign, and false-positive patterns, extracted by experts, from selected MR studies, by using an incremental learning algorithm. After training, the network was tested by means of a consistency checking test, cross validation techniques, and patterns from actual MR breast images. During the consistency test, the BNN was tested by using the same patterns used for training. The BNN classification accuracy in this case was 99.75%, proving the ability of the BNN to select useful patterns from the training set. Then, a leave one out cross-validation (LOOCV) test was done by using patterns from the training set and the classification accuracy was 90%. Next, an extended training set was created by shifting the original patterns in different directions. A cross-validation test was then performed by dividing the set of patterns into a training and a test set. Classification accuracy was compared to the nearest neighbor classifier. Results showed that the BNN achieved an average of 77% classification accuracy while requiring only 34% of the original training set. On the other hand, the nearest neighbor classifier achieved an accuracy of 57.9% while retaining the whole training set. Another test using actual MR slices different from the training set was done and results compared favorably to a radiologist's findings. Test results show the BNN's capability to detect suspected malignant regions in 3D MR images of the breast. The proposed BNN architecture can save the radiologist a great deal of time browsing MR slices searching for suspected malignancies.

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.

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.

Mycobacterium kansasii pulmonary infection in patients with AIDS: spectrum of chest radiographic findings

PURPOSE

To determine the chest radiographic findings and clinical manifestations of Mycobacterium kansasii pulmonary infection in patients with acquired immunodeficiency syndrome (AIDS).

MATERIALS AND METHODS

Criteria for diagnosis included two or more positive cultures from respiratory sources, pulmonary symptoms or fever, and no other identifiable cause of pulmonary disease. Chest radiographs at initial examination and follow-up were evaluated for parenchymal opacities, cavitation, adenopathy, and pleural effusions. Medical records were reviewed for clinical signs and symptoms, CD4 cell count, presence of additional pathogens, and response to antimycobacterial therapy.

RESULTS

Of 96 patients, 16 (17%) satisfied all criteria for M kansasii pulmonary infection. The mean CD4 cell count was 24/mm3. Twelve patients (75%) demonstrated alveolar opacities, only three (19%) of which were cavitary. Interstitial opacities (6%) and pleural effusions (12%) were uncommon. Four (25%) patients had thoracic lymphadenopathy, which was the only positive radiographic finding in two patients. Fourteen patients were treated for M kansasii, and 10 (71%) showed clinical and radiographic improvement.

CONCLUSION

Patients with AIDS and pulmonary M kansasii frequently demonstrate focal alveolar opacities. Symptomatic patients with pulmonary nontuberculous mycobacteria should be presumptively treated for pulmonary M kansasii until final culture results are available.

Cytomegalovirus pneumonia manifesting as a focal mass in acquired immunodeficiency syndrome

Although cytomegalovirus (CMV) is commonly found in the lungs of patients with acquired immunodeficiency syndrome (AIDS), CMV is an infrequent cause of pneumonia in AIDS. We describe an unusual case of proven CMV pneumonia in an AIDS patient that manifested as a large mass on chest radiography and computed tomography. The mass regressed on antiviral therapy. CMV pneumonia should be included in the differential diagnosis of a lung mass in patients with AIDS.

Bronchogenic carcinoma in HIV-positive patients: findings on chest radiographs and CT scans

OBJECTIVE

The radiographic manifestations of bronchogenic carcinoma in HIV-positive individuals may resemble or accompany changes of inflammatory disease. To provide information that is useful in the differential diagnosis, we studied the findings on plain radiographs and chest CT scans in 30 HIV-positive patients with proven bronchogenic carcinoma and correlated the radiographic features with the presence or absence of thoracic opportunistic infection.

SUBJECTS AND METHODS

Thirty HIV-positive individuals had bronchogenic carcinoma diagnosed at our institution between 1986 and 1993. Fourteen (47%) of the 30 had AIDS at the time of cancer diagnosis. All but one of the patients were men, and the median age at diagnosis was 48 years (range, 32-66 years). Most (90%) had a history of smoking. Eighteen (60%) of the 30 had a history of pulmonary tuberculosis, Pneumocystis carinii pneumonia, or both. We retrospectively reviewed all available chest radiographs (n = 27) and chest CT scans (n = 25) for tumor size and location, adenopathy, pleural disease, and pulmonary infiltrates.

RESULTS

Eighteen tumors (60%) were peripheral, 11 (37%) were central (hilar or mediastinal), and one manifested as a metastatic pleural mass. Of the peripheral tumors, 17 (94%) were in the upper lobes. All the central tumors showed obstructive consolidation of lung in the distribution of the affected airway. Adenopathy was present in 63% of the patients, and pleural effusions or masses were seen in 33%. A history of tuberculosis or Pneumocystis carinii pneumonia was present in 83% of the patients with peripheral tumors but only 27% of the patients with central lesions (p = .005). Superimposed infiltrates were present in six patients (20%). Three (17%) of 18 peripheral tumors were obscured by or mistaken for inflammatory disease, delaying the diagnosis of cancer.

CONCLUSION

Bronchogenic carcinoma usually manifests as a peripheral upper lobe mass in HIV-positive patients with a history of tuberculosis or Pneumocystis carinii pneumonia, whereas central masses are more common in patients without a history of thoracic opportunistic infection. Carcinoma should be suspected in patients with peripheral lesions that persist despite appropriate antibiotic therapy.

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.

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.

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.

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 19F NMR imaging of the cardiovascular system

A technique is described that permits the 19F nuclear magnetic resonance (NMR) imaging of the vascular system in animals that have been infused with certain perfluorocarbon blood substitutes. The essence of the technique is the selection for imaging of a narrow group of spectral lines from the fluorocarbon using a combination of selective excitation and selective spin echo. For perfluorotributylamine (FTBA), this uses 56% of the available fluorine signal. Both slice and whole body projection images were obtained. The method was studied on an experimental NMR imaging system based on a 1.4 T, 31 cm diameter magnet. Phantom tests showed that misregistration artifacts, due to the imaging of unwanted spectral lines, were negligible. The spatial resolution obtained in a scan time of 8.5 min was approximately 1 mm. The technique was tested with living rats in which 50% of the blood volume was replaced with an emulsion of FTBA. Short echo times, less than 15 ms, were essential to avoid losing signal from flow effects in the larger vessels. Structures identified included the heart, liver, spleen, lungs, kidneys, and major veins. A diffuse fluorine signal seen in most tissues is indicative of tissue perfusion. The problems and possibilities of potential clinical applications are discussed.

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.

Experimental intracranial septic infarction: magnetic resonance enhancement

Intracranial brain abscess was produced in three monkeys by embolization of a small pledget of polyvinyl alcohol (PVA) soaked in a broth of Staphylococcus aureus. Imaging of the chronic stable abscess was performed on the General Electric 8800 CT unit (Milwaukee, Wis.) and a 1.4 T superconducting small bore imaging system. Magnetic resonance imaging included saturation recovery, inversion recovery, and spin echo techniques. MR imaging was also performed after paramagnetic enhancement using gadolinium-DPTA (Gd-DTPA). Our results show that paramagnetic enhancement with T1-weighted imaging adds specificity and enables rapid assessment of abnormalities of the blood-brain barrier. T2-weighted imaging without paramagnetic enhancement was very sensitive in defining areas of abnormality in the brain but in our experiment lacked specificity. T2-weighted imaging with Gd-DTPA demonstrated no obvious change in the appearance of the lesion. The combination of T1-weighted Gd-DTPA and T2-weighted imaging appeared complementary in our experiment, and these images correlated well with the pathologic findings.

Congenital sensorineural deafness associated with EEG abnormalities, epilepsy and high familial incidence

A clinical study was carried out on 31 deaf children attending a school for the deaf in Beer Sheva, Israel. 71 per cent of the pupils were found to have familial deafness. EEG studies showed a high rate of abnormal tracings associated with congenital sensorineural deafness. A significant number of EEGs were paroxysmal. The majority of cases occurred among children with hereditary deafness. Behaviour disturbances were common among the children with abnormal EEGs. One-third of the pupils had additional congenital defects, including three cases of retinitis pigmentosa. Four children (12 X 9 per cent) had epilepsy; two cases of petit mal were of special interest. Hereditary aspects of congenital nerve deafness and the implications of the EEG findings are discussed.

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.