Halo Of Ground-glass Attenuation Research Articles

THE TALE OF A HALO SIGN

SESSION TITLE: Fellows Imaging Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Halo sign on chest imaging is characterized by a circular area of ground-glass attenuation around a central pulmonary nodule or mass. It is most commonly associated with invasive fungal infections; however, can also be seen in a wide range of neoplastic and inflammatory conditions. Here we present a case of angio-invasive neoplasm presenting with characteristic halo sign in an immunocompromised patient. CASE PRESENTATION: A 62-year-old male with alcoholic cirrhosis post orthotopic liver transplant on chronic immunosuppression with recurrent cirrhosis of his graft liver was initially admitted for management of acute hepatic encephalopathy. A CT scan of his chest showed numerous part solid centrilobular nodules bilaterally with central solid component and surrounding ground glass halo. Invasive fungal infection was suspected, and micafungin was initiated. Serum aspergillus antigen and beta D-glucan were negative. He underwent bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). BAL was negative for bacterial, fungal and acid-fast bacilli cultures. Pathology from the TBB showed atypical epithelioid cells that could be reactive or due to a metastatic disease. A repeat CT scan performed after 10 days of antifungal therapy showed a significant increase in size of the previously noted centrilobular nodules with surrounding ground glass halo. Surgical open lung biopsy was considered but he was deemed to be a poor surgical candidate due to his frailty and comorbidities. Transbronchial cryobiopsy was then performed which showed poorly differentiated epithelioid neoplasm predominantly within the vascular spaces. Based on immunohistochemical staining positive for both cytokeratin and vascular markers, a differential diagnosis of epithelioid angiosarcoma vs. epithelioid sarcoma was made. After detailed discussion with him and his family in regards to his overall prognosis, he wished for no further testing or interventions and chose to go home with hospice. DISCUSSION: Halo sign indicates presence of hemorrhagic nodules. It was first described in immunocompromised patients with invasive pulmonary aspergillosis where the nodule itself is a focus of pulmonary infarction with surrounding alveolar hemorrhage. However, it has now been associated with a variety of pulmonary diseases including both infectious and non-infectious hemorrhagic nodules, tumor cell infiltration and few non-hemorrhagic etiologies. Metastatic lung disease from hyper vascular tumors such as angiosarcoma, chondrosarcoma and melanoma can form a halo of ground glass attenuation as a result of peritumoral hemorrhage or infiltration. Malignancy is a leading cause of death in post liver transplant patients and should always be considered in the evaluation of these patients. CONCLUSIONS: While evaluating halo sign a wide differential should be considered including malignancy in a post liver transplant patient. Reference #1: Georgiadou SP, Sipsas NV, Marom EM, Kontoyiannis DP. The diagnostic value of halo and reversed halo signs for invasive mold infections in compromised hosts. Clin Infect Dis. 2011;52(9):1144-1155. doi:10.1093/cid/cir122 Reference #2: Parrón M, Torres I, Pardo M, Morales C, Navarro M, Martínez-Schmizcraft M. Signo del halo en la tomografía computarizada de tórax: diagnóstico diferencial con correlación anatomopatológica [The halo sign in computed tomography images: differential diagnosis and correlation with pathology findings]. Arch Bronconeumol. 2008;44(7):386-392. DISCLOSURES: No relevant relationships by Sadia Benzaquen, source=Web Response No relevant relationships by Ena Gupta, source=Web Response No relevant relationships by ATUL MATTA, source=Web Response No relevant relationships by Corrado Minimo, source=Web Response No relevant relationships by Carlos Oberto, source=Web Response

The halo sign of Q fever pneumonia

A previously healthy 29-year-old male in intimate contact with dogs presented with a five-day history of high fever, chills, headache, myalgia and nonproductive cough. He also complained of sharp right-sided chest pain worse on deep inspiration. On physical examination, the patient was febrile, tachypneic and tachycardic. Inspiratory rales were heard over the right lower lung zone. Laboratory data showed a white blood cell (WBC) count of 6.6 × 109/L with a left shift. Inflammatory markers were mildly elevated with erythrocyte sedimentation rate (ESR) 37 mm/h and C-reactive protein (CRP) 32 mg/L. A computed tomography (CT) scan of the chest revealed a 3 cm × 3 cm, well-defined and round mass surrounded by a halo of ground-glass attenuation, namely the halo sign, in the posterior basal segment of the right inferior lobe (Fig. 1). Serologic test was positive for Coxiella burnetii (C. burnetii) by indirect immunofluorescence assay (IFA). Empirical treatment was initiated with azithromycin (0.5 g daily), which was changed to doxycycline (100 mg twice a day) for 14 days. A follow-up CT scan performed four weeks later showed total resolution of the lesions. At six-month follow-up, the patient was asymptomatic with no radiological evidence of a relapse. Pneumonia is one of the cardinal manifestations of Q fever, which caused by C. burnetii infection.1 Q fever is probably the most common cause of round pneumonia in adults.2 The halo sign refers to a zone of ground-glass attenuation surrounding the circumference of a pulmonary nodule or mass on

Transient Pulmonary Eosinophilia Incidentally Found on Low-Dose Computed Tomography

To describe computed tomography (CT) findings of transient pulmonary eosinophilia (TPE) incidentally found on low-dose CT (LDCT) and to identify suggestive CT features helpful in initial diagnosis. We retrospectively reviewed LDCT scans in 40 individuals who met criteria for having TPE. There were 35 men and 5 women (age range, 32-62 years; mean, 48.5 +/- 9 years). Initial LDCT scans were assessed as either (a) nodules, further characterized as either solid, solid associated with a halo of ground-glass attenuation, or pure ground-glass lesions as well as by number, size, and location or (b) ill-defined foci of parenchymal consolidation. A range of focal parenchymal abnormalities (n = 78) were identified-both single (48%) and multiple (52%). Most of these proved to be either solid nodules with discrete ground-glass halos (72%), or poorly defined solid nodules exhibiting a variety of differing morphologies (24%). Ill-defined foci of consolidation were noted in 3 cases (4%). The lesions were predominantly located in the lower lung zone (73%) with peripheral distribution (92%). Transient pulmonary eosinophilia most often manifests as solid nodules with associated ground-glass halos. Awareness of TPE should serve to limit the number of mistaken diagnoses of early lung cancer.

Pulmonary Computed Tomography Findings of Visceral Larva Migrans Caused by Ascaris suum

To retrospectively evaluate the computed tomography (CT) findings of pulmonary involvement in patients with visceral larva migrans caused by Ascaris suum. Institutional review board approval was obtained, and informed consent was waived. Chest CT scans obtained between January 1994 and November 2005 in 32 patients infected with A. suum were retrospectively evaluated by 3 chest radiologists. In 4 patients who underwent surgical or transbronchial biopsy, comparisons of the CT images with the actual specimens were performed. On CT scans, abnormal findings were seen in 28 patients. The most common abnormality consisted of nodules (n = 19) in which the majority had a halo of ground-glass attenuation (n = 17), followed by ground-glass attenuation (n = 18), and interlobular septal thickening (n = 14). These abnormalities were predominantly seen in the peripheral lung (n = 25). Of the 7 patients who underwent follow-up CT scans, nodules (n = 6) and ground-glass attenuation (n = 5) had migrated in 4 patients. Pathologically, these findings corresponded to marked eosinophilic infiltration into the interstitium. These CT findings are considered to be suggestive of thoracic involvement in patients with visceral larva migrans caused by A. suum.

Primary angiosarcoma of the lung

Primary angiosarcoma of the lung is a rare disorder with few cases reported in the literature [Patel AM, Ryu JH. Angiosarcoma in the lung. Chest 1993;103:1531-35]. We present a case of primary angiosarcoma of the lung in a 79-year-old woman. Preoperative computed tomographic scan revealed soft tissue nodules surrounded by a halo of ground-glass attenuation, an appearance consistent with hemorrhagic pulmonary nodules [Primack S, Hartman T, Lee KS. Pulmonary nodules and the CT halo sign. Radiology 1994;190:513-15]. Lung biopsy revealed a multifocal malignant neoplasm with areas of hemorrhage. The histologic, cytologic, and immunophenotypic features were characteristic of epithelioid angiosarcoma. This case report contributes to the sparse literature on this disease and provides computed tomographic and pathologic correlation in a patient with hemorrhagic pulmonary nodules.

CT halo sign: the spectrum of pulmonary diseases

The CT halo sign indicates ground glass attenuation surrounding a pulmonary nodule on CT. Although it was initially proposed as an early, specific finding of invasive pulmonary aspergillosis, it can be caused by many other pathological conditions such as infection, neoplastic and inflammatory diseases. The halo of ground glass attenuation pathologically represents pulmonary haemorrhage, tumour infiltration, or non-haemorrhagic inflammatory processes. Although non-specific, this sign is important because the clinical setting and associated radiological features may give a clue to the differential diagnosis. In this review, we demonstrate the spectrum of pulmonary diseases showing the "CT halo sign" on thin-section CT and discuss their radiological and clinical features.

Spectrum of pulmonary aspergillosis: histologic, clinical, and radiologic findings.

Aspergillosis is a serious pathologic condition caused by Aspergillus organisms and is frequently seen in immunocompromised patients. At computed tomography (CT), saprophytic aspergillosis (aspergilloma) is characterized by a mass with soft-tissue attenuation within a lung cavity. The mass is typically separated from the cavity wall by an airspace ("air crescent" sign) and is often associated with thickening of the wall and adjacent pleura. CT findings in allergic bronchopulmonary aspergillosis consist primarily of mucoid impaction and bronchiectasis involving predominantly the segmental and subsegmental bronchi of the upper lobes. Aspergillus necrotizing bronchitis may manifest as an endobronchial mass, obstructive pneumonitis or collapse, or a hilar mass. Bronchiolitis is characterized by centrilobular nodules and branching linear or nodular areas of increased attenuation ("tree-in-bud" pattern). Obstructing bronchopulmonary aspergillosis mimics allergic bronchopulmonary aspergillosis at CT and manifests as bilateral bronchial and bronchiolar dilatation, large mucoid impactions, and diffuse lower lobe consolidation caused by postobstructive atelectasis. Characteristic CT findings in angioinvasive aspergillosis consist of nodules surrounded by a halo of ground-glass attenuation ("halo sign") or pleura-based, wedge-shaped areas of consolidation. Although imaging findings in pulmonary aspergillosis may be nonspecific, in the appropriate clinical setting, familiarity with the CT findings may suggest or even help establish the diagnosis.

Pulmonary complications after bone marrow transplantation: high-resolution CT and pathologic findings.

A wide variety of pulmonary complications occur in bone marrow transplant (BMT) recipients and are a major cause of morbidity and death. High-resolution computed tomography (CT) is excellent in the detection of pulmonary abnormalities, but these findings are generally nonspecific. However, the different complications, which reflect the immunologic status of the patients, occur in three phases. This pattern can be used to interpret CT scans. The neutropenic phase (up to 3 weeks after BMT) is characterized by fungal infections, notably angioinvasive aspergillosis, alveolar hemorrhage, pulmonary edema, and drug reactions. At CT, angioinvasive aspergillosis appears as a nodule surrounded by a halo of ground-glass attenuation; alveolar hemorrhage and drug reactions, as bilateral areas of ground-glass attenuation or consolidation; and pulmonary edema, as prominent pulmonary vessels, interlobar septal thickening, ground-glass attenuation, and pleural effusions. The second phase (3 weeks to 100 days after BMT) is dominated by cytomegalovirus pneumonia, which appears as multiple small nodules with associated areas of consolidation or ground-glass attenuation, and Pneumocystis carinii pneumonia, which appears predominantly as ground-glass attenuation. The late phase (more than 100 days after BMT) is characterized by bronchiolitis obliterans, bronchiolitis obliterans with organizing pneumonia (BOOP), and chronic graft-versus-host disease. In bronchiolitis obliterans, CT reveals bronchial dilatation and a mosaic pattern of attenuation; in BOOP, CT findings usually consist of patchy consolidation or ground-glass attenuation. If CT findings are considered in relation to the time elapsed after BMT, diagnostic options can be narrowed sufficiently to enable accurate diagnosis.

Pulmonary involvement of idiopathic hypereosinophilic syndrome: CT findings in five patients.

The aim of this study was to assess the CT findings of pulmonary involvement in patients with idiopathic hypereosinophilic syndrome (HES). The study included five patients with idiopathic HES who had pulmonary involvement proven by bronchoalveolar lavage (n = 3) or based on clinical and radiologic findings (n = 2). Four patients had high resolution CT and one had conventional CT. The CT scans were retrospectively reviewed by two chest radiologists for pattern and distribution of disease. All five patients had several small nodules in both lungs at CT scan. Four patients had nodules with a halo of ground-glass attenuation. Three patients had focal areas of ground-glass attenuation in both lungs. These lesions were present in all lung zones and involved mainly the peripheral lung. There was neither lobar predilection nor peribronchovascular distribution. Other organs involved included bone marrow (n = 3), liver (n = 3), stomach (n = 1), and peritoneum (n = 1). The CT findings of pulmonary involvement in patients with idiopathic HES included small nodules with or without a halo of ground-glass attenuation and focal areas of ground-glass attenuation mainly in the lung periphery.

Intrathoracic lymphoproliferative disorders in the immunocompromised patient: CT findings.

To assess the computed tomographic (CT) findings of intrathoracic lymphoproliferative disorders in the immunocompromised patient. The authors retrospectively reviewed CT scans of the chest in 18 consecutive patients with pathologically proved intrathoracic lymphoproliferative disorders. Twelve patients had the acquired immunodeficiency syndrome (AIDS), and six were receiving immunosuppressive therapy. Final diagnosis included AIDS-related diffuse lymphoid hyperplasia (n = 1), lymphocytic interstitial pneumonia (LIP) (n = 3), posttransplantation lymphoproliferative disorders (PTLDs) (n = 4), and lymphoma (n = 10). Diffuse areas of ground-glass attenuation were found in the patient with lymphoid hyperplasia and the three patients with LIP. The four patients with PTLDs had multiple, well-circumscribed pulmonary nodules, and nodules in three of the four patients had a halo of ground-glass attenuation. Nine of the 10 patients with lymphoma had well-circumscribed nodules or nodules with consolidation. Mediastinal lymph node enlargement was present in two patients with PTLDs and three patients with lymphoma. The intrathoracic CT findings of lymphoproliferative disorders appear to be similar in immunocompromised patients with and without AIDS and are usually extranodal.