PE MIMICS: a structured approach for the emergency radiologist in the evaluation of chest pain.

Chest pain is a common reason for presentation to the emergency department. In many cases, a CTPA or CT thoracic aorta is performed during work up to assess for pulmonary embolism and aortic pathology, critical diagnoses that can be difficult to out rule clinically. However, the causes of chest pain are myriad. It is therefore crucial for the interpreting radiologist to be cognizant of other potential etiologies when interpreting these studies. The purpose of this pictorial essay is to highlight the causes of non-PE or aortic-related chest pain and provide radiologists with a structured approach to interpreting these studies, ensuring a comprehensive search strategy so that important pathologies are not missed.

Understanding chest radiographic anatomy with MDCT reformations.

Chest radiograph interpretation requires an understanding of the mediastinal reflections and anatomical structures. Computed tomography (CT) improves the learning of three-dimensional (3D) anatomy, and more recently multidetector CT (MDCT) technology has enabled the creation of high-quality reformations in varying projections. Multiplanar reformations (MPRs) of varying thickness in the coronal and sagittal projections can be created for direct correlation with findings on frontal and lateral chest radiographs, respectively. MPRs enable simultaneous visualization of the craniocaudal extent of thoracic structures while providing the anatomic detail that has been previously illustrated using cadaveric specimens. Emphasis will be placed on improving knowledge of mediastinal anatomy and reflections including edges, lines, and stripes that are visible on chest radiographs.

Cancer gene therapy using a novel secretable trimeric TRAIL.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF family, is a type II transmembrane cytokine molecule. Soluble TRAIL has been shown to induce apoptosis in a wide variety of cancer cells in vitro and to suppress tumor growth specifically without damaging normal cells and tissues in vivo. In our previous report, we have demonstrated that an artificial gene encoding the polypeptide composed of the three functional elements (a secretion signal, a trimerization domain and an apoptosis-inducing moiety of TRAIL gene sequence) expresses and secretes highly apoptotic trimeric TRAIL into the culture supernatant. Here, as an approach to TRAIL-based cancer gene therapy, we developed an adenoviral vector delivering the gene that encodes our secretable trimeric TRAIL (stTRAIL). This adenovirus (Ad-stTRAIL) potently induced apoptosis in vitro in cancer cell lines such as HeLa, MDA-MB-231, A549, HCT116 and U-87MG. In an animal xenograft tumor model bearing a human glioma cell line U-87MG, intratumoral delivery of Ad-stTRAIL dramatically suppressed tumor growth without showing detectable adverse side effects. Histological analysis revealed that Ad-stTRAIL suppresses tumor growth by inducing apoptotic cell death. Contrary to the known rapid clearance of systemically delivered TRAIL protein from the blood circulation, stTRAIL expressed by Ad-stTRAIL in tumor tissues persisted for more than 4 days. In a comparison of tumor suppressor activity between Ad-stTRAIL and Ad-flTRAIL (delivering the full-length TRAIL gene) after mixing infected cells with uninfected cells and implanting these mixed cells in nude mice, Ad-stTRAIL showed higher tumor suppressor activity than that of Ad-flTRAIL. Our data reveal that a gene therapy using Ad-stTRAIL has a promising potential to treat human cancers including gliomas.

Factors influencing pneumothorax rate at lung biopsy: are dwell time and angle of pleural puncture contributing factors?

PURPOSE: To study factors that may influence pneumothorax and chest tube placement rate, especially needle dwell time and pleural puncture angle. MATERIALS AND METHODS: In 159 patients, 160 coaxial computed tomography (CT)-guided lung biopsies were performed. Dwell time, the time between pleural puncture and needle removal, was calculated. The smallest angle of the needle with the pleura ("needle-pleural angle") was measured. These and other variables were correlated with pneumothorax and chest tube rates. RESULTS: One hundred fifty biopsies were included. There were 58 (39%) pneumothoraces (14 noted only at CT), with eight (5%) biopsies resulting in chest tube placement. Longer dwell times (mean, 29 minutes; range, 12-66 minutes) did not correlate with pneumothoraces (P =.81). Smaller needle-pleural angles (< 80 degrees) [corrected], decreased forced expiratory volume in 1 second to vital capacity ratio (<50%), lateral pleural puncture, and lesions along fissures were associated with higher [corrected] pneumothorax rates (P <.05). Emphysema along the needle path, pulmonary function tests showing ventilatory obstruction, and lesions along fissures predisposed patients to chest tube placement (P <.05). Pleural thickening and prior surgery were associated with lower pneumothorax rates (P <.05). CONCLUSION: Longer dwell times do not correlate with pneumothorax and should not influence the decision to obtain more biopsy samples. A shallow pleural puncture angle may increase the pneumothorax rate.

Chest CT: automated nodule detection and assessment of change over time--preliminary experience.

The authors developed a computer system that automatically identifies nodules at chest computed tomography, quantifies their diameter, and assesses for change in size at follow-up. The automated nodule detection system identified 318 (86%) of 370 nodules in 16 studies (eight initial and eight follow-up studies) obtained in eight oncology patients with known nodules. Assessment of change in nodule size by the computer matched that by the thoracic radiologist (Spearman rank correlation coefficient, 0.932).

Tuberculosis from head to toe.

Tuberculosis can affect virtually any organ system in the body and can be devastating if left untreated. The increasing prevalence of tuberculosis in both immunocompetent and immunocompromised individuals in recent years makes this disease a topic of universal concern. Because tuberculosis demonstrates a variety of clinical and radiologic findings and has a known propensity for dissemination from its primary site, it can mimic numerous other disease entities. Primary pulmonary tuberculosis typically manifests radiologically as parenchymal disease, lymphadenopathy, pleural effusion, miliary disease, or lobar or segmental atelectasis. In postprimary tuberculosis, the earliest radiologic finding is the development of patchy, ill-defined segmental consolidation. Both computed tomography (CT) and magnetic resonance (MR) imaging are helpful in diagnosing tuberculous spondylitis and tuberculous arthritis. CT is especially useful in depicting gastrointestinal and genitourinary tuberculosis. In tuberculosis involving the central nervous system, CT and MR imaging findings vary depending on the stage of disease and the character of the lesion. A high degree of clinical suspicion and familiarity with the various radiologic manifestations of tuberculosis allow early diagnosis and timely initiation of appropriate therapy, thereby reducing patient morbidity.

CT manifestations of respiratory syncytial virus infection in lung transplant recipients.

PURPOSE: The purpose of our study was to evaluate CT findings during respiratory syncytial virus (RSV) infection in lung transplant recipients and to identify sequelae. METHOD: Thirty-nine CT scans prior to, during, and following acute infection in 10 lung transplant recipients were reviewed. Abnormalities that were new from baseline observations and occurred within 4 weeks of diagnosis were defined as acute. Chronic findings were defined as those present >4 weeks after diagnosis. RESULTS: Findings in nine patients were ground-glass (seven), air-space (five), and tree-in-bud (four) opacities and acute bronchial dilatation (four) and wall thickening (four). Patients lacked pleural effusions or lymph node enlargement. Five of seven patients with follow-up exams had new air trapping (three), persistent bronchial dilatation (three), and thickening (two). Three and 2 of the 10 patients developed bronchiolitis obliterans syndrome and obliterative bronchiolitis, respectively. CONCLUSION: During acute infection, patients commonly had ground-glass opacities but lacked pleural effusions and lymph node enlargement. There can be chronic sequelae after infection.

Magnetic resonance imaging of pericardial constriction: comparison of cine MR angiography and spin-echo techniques.

AIM: Spin-echo (SE) MRI detects pericardial thickening in pericardial constriction but the validity of extrapolating SE criteria to cine MRA imaging has not been tested. Pericardial thickness measured by SE and cine MRA was compared in patients with and without pericardial thickening to determine if the range of pericardial thickness measured by the two techniques is the same. PATIENT AND METHODS: Fourteen patients, investigated for possible pericardial constriction (PC), were compared with 24 subjects without evidence of pericardial disease (controls). Images were acquired using SE and cine MRA. Pericardial thickness was compared with final diagnosis. RESULTS: Pericardial thickening ( > 3.5 mm) by SE detected pericardial constriction: sensitivity = 100% specificity = 96%, kappa = 0.91. Cine MRA had a sensitivity = 86%, specificity = 63%, kappa = 0.33. Maximum differences between SE and cine MRA pericardial thickness ranged from +2.5 mm to -2/7 mm. CONCLUSIONS: Spin-echo identifies pericardial thickening with little overlap between measurements in patients with and without pericardial constriction. Pericardial thickness on cine MRA usually exceeds SE thickness, but with considerable overlap of thickness measurements in patients with and without pericardial constriction. Cine MRA cannot be used alone to diagnose pericardial thickening.

Electroconvulsive shock reduces inositol 1,4,5-trisphosphate 3-kinase mRNA expression in rat dentate gyrus.

We investigated the expression of inositol 1,4,5-trisphosphate (InsP3) 3-kinase mRNA after a single electroconvulsive shock (ECS) with in situ hybridization histochemistry in rat brain. At 6 h after ECS, the expression was markedly decreased in the dentate gyrus, and the decrease was maintained until 9 h with a slight recovery. The InsP3 3-kinase mRNA content returned to basal levels after 12 h. We could not detect any apparent changes in the expression of InsP3 3-kinase mRNA in the CA1-CA3 areas of hippocampus, the striatum, and the cerebral cortex at any time point examined. In the temporal pattern, the reduction of the expression in the dentate gyrus was preceded by the induction of c-fos after ECS. These observations suggest that the InsP3 3-kinase might be one of the genes whose expression can be altered by ECS.

Atypical contrast enhancement of computerized tomography of demyelinating disease.

Atypical contrast enhancement of a myelinoclastic lesion, as demonstrated by computerized tomography, is reported in a clinically and pathologically regressing lesion.

Familial intracranial aneurysms. Six cases among 13 siblings.

The authors present a family of 13 siblings: six are proven to have had intracranial aneurysms, five have had elective cerebral angiography with normal findings, and two have refused angiography. Of the six aneurysm cases, two had disabling and one had fatal subarachnoid hemorrhages; three underwent successful clipping of their aneurysms which were discovered by elective angiography. It is concluded that the two remaining patients who have refused angiography have a 50% statistical chance of harboring a potentially lethal aneurysm, for in this family the occurrences of six proven cases among 11 siblings studied is consistent with a dominant Mendelian inheritance.

Cerebral vasospasm: a clinical observation.

Three cases of subarachnoid hemorrhage from intracranial aneurysms are presented. Two of the patients survived long enough to develop delayed cerebral vasospasm. The computerized tomograms and angiograms were correlated with the clinical course. It is suggested that delayed cerebral vasospasm may be preceded by relative vasodilation, or at least inhibition of vasocontraction, and concomitant increased vascular permeability of the parent vessels diagnosed by contrast enhanced computerized tomography. This phenomenon, if confirmed in larger series of patients, may allow prediction of that patient destined for vasospasm and may suggest some of the pathophysiology of this devastating problem.