Diagnostic imaging of pneumonia and its complications in the critically ill patient

Chest radiography and other radiographic imaging techniques often are extremely useful in the differential diagnosis of chest diseases in ICU patients. It should be remembered, however, that the findings on these imaging studies often are nonspecific. Also, different pathologic processes may be present in a patient's lungs at the same time. Clinical parameters, medical diagnostic studies, and laboratory studies are important in the differentiation of disease processes in these patients. The radiologist should work closely with the clinician to provide optimal care for patients in the ICU setting.

Magnetization transfer magnetic resonance imaging of parenchymal lung disease

RATIONALE AND OBJECTIVES

Magnetic resonance imaging with magnetization transfer (MT) contrast recently has been described as a method that may provide additional information about the macromolecular composition of tissue. Magnetization transfer contrast images were compared to conventional gradient-recalled echo images in a variety of pulmonary parenchymal diseases and normal lung.

METHODS

Single-slice gradient echo images were obtained with and without an off-resonance radio frequency pulse on a 0.1T MR scanner. The change in signal intensity between identical regions of interest on non-MT and MT images was determined in 13 patients with known lung disease, five healthy volunteers, and three postmortem atelectatic dog lungs.

RESULTS

No significant change in signal intensity (MT effect) was observed in fat, flowing blood, normal lung, atelectatic lung, or in acute pulmonary edema. Chronic parenchymal lung disease showed the greatest MT effect, 37.7% +/- 7.5. Acute infectious lung disease showed an intermediate degree of MT effect, 19.5% +/- 3.0.

CONCLUSIONS

Magnetization transfer contrast magnetic resonance imaging of pulmonary disease is feasible at low field strength and may be useful in the characterization and differentiation of pulmonary parenchymal abnormalities. Magnetization transfer contrast appears to be proportional to the amount of interstitial fibrosis in lung parenchyma, while acute inflammatory cell infiltration exhibits less MT effect and acute pulmonary edema exhibits very little.

Diagnostic and therapeutic evaluation of bronchoscopy

The diagnostic and therapeutic efficacy of bronchoscopy was determined in 85 children. The major indications were foreign body removal in younger patients and evaluation of tracheobronchial pathology in older children. Foreign body was commonly isolated in the toddlers and even in the elder age group (19%) as well as in those with suspected ingestion (44%). Groundnut was the predominant foreign body and right bronchus was the most frequent site. Tracheobronchitis (27%), bronchiectasis (13%) endobronchial tuberculosis (9.4%) and mucus plug (3%) were the other frequent findings. Bronchography was performed in 16 patients and it confirmed the diagnosis in 75% of the cases. Minor complications were encountered in 8% of patients. In the present study bronchoscopy yielded definite results in 83% and in many, including those with normal findings it guided further management.

[Bromocriptine-induced pleuropneumopathy]

A 64-year-old man was diagnosed to have Parkinson's disease when aged 42 years and since then has been treated with levodopa and benserazide (up to 875 mg daily). Bromocriptine (up to 35 mg daily) was added to the medication 9 years ago. 3 1/2 years ago he developed exertional dyspnoea (NYHA class II-III) and lost 5 kg in weight. Chest radiography demonstrated pleural effusion and interstitial pulmonary changes in both lung bases. Erythrocyte sedimentation rate was 37 mm in the first hour and the white cell count 10,400/microliters. Extensive tests failed to find malignant tumour or any infectious-inflammatory condition. As it was suspected that the pleuropulmonary changes were associated with the bromocriptine intake, it was discontinued and biperiden and selegiline substituted for it. The pleural effusion regressed almost completely within 8 weeks, and the laboratory tests pointing to inflammation disappeared completely. Clinical, biochemical and radiological tests have remained normal for the last 3 years. The clinical course makes a causal relationship between bromocriptine intake and the pleuropulmonary changes highly probable.

[Rounded nodular atelectasis: computerized tomography and magnetic resonance appearances]

Rounded atelectasis is a rare form of lung collapse whose X-ray appearance can be confused with that of tumors, especially nodular forms. We studied 14 such lesions with computerized tomography, finding that all were rounded and subpleural, specifically in the thickened pleura visceralis. The radiological sign that was most useful for diagnosis was the arc of the proximal vessels in the direction of the lesion. Such an arc was present in all the cases we reviewed. Other radiological signs such as brightness of the surrounding parenchyma, loss of volume in the affected lobe and the presence of air bronchogram were found in 10, 7 and 7 patients, respectively. When the X-ray appearance clearly indicates a diagnosis of rounded nodular atelectasis, we recommend that no additional diagnostic procedure be made. Three lesions in our sample were studied by magnetic resonance, which revealed the characteristic hypointense curves in all sequences done on 2 patients. The usefulness of computerized tomography in the diagnosis of this entity relegates magnetic resonance to a second plane.

Ovarian hyperstimulation syndrome with minimal ascites and massive pleural effusion: report of a case

A 30-year-old woman was admitted to the hospital due to bilateral massive pleural effusion and right lung collapse with severe respiratory distress. She had been undergoing gamete intrafallopian transfer (GIFT) following three years of primary infertility. Ovarian stimulation was done with pure follicle stimulating hormone (FSH) and human menopausal gonadotropin (hMG) under pituitary suppression with leuprolide acetate. Bilateral chest pain and progressive dyspnea occurred six days after preovulatory oocytes with washed motile sperms were transferred laparoscopically to the fallopian tubes. Chest radiography, sonography and computed tomography revealed a massive right pleural effusion with right lung collapse, and a mild left pleural effusion. Abdominal sonography revealed minimal ascites. Supportive therapy including fluid supply and albumin infusion failed to improve the respiratory distress. A tube thoracostomy was performed, resulting in rapid reexpansion of the lung. The respiratory distress improved markedly after drainage of 6,800 mL of pleural effusion over 7 days. Massive serosanguineous pleural effusion with minimal ascites is unusual in ovarian hyperstimulation syndrome (OHSS). Tube thoracostomy is a safe and effective treatment for massive pleural effusion and lung collapse in the case of OHSS.

[Serial changes of atelectasis in acute bronchial obstruction: MR imaging pathologic correlation in experimental animal model study]

OBJECTIVE

To evaluate MR imaging (MRI) of atelectatic lungs caused by acute bronchial obstruction.

SUBJECTS AND METHODS

In 12 Japanese white rabbits, sudden obstruction of one main bronchus was induced with compressed polyvinyl-alcohol sponge plugs, and three rabbits each were sacrificed at 3, 7, 14, and 21 days. Unilateral complete airway obstruction persisted in 8 of the 12 rabbits. After T1: [500/20/2 (TR/TE/excitations), 5 mm thickness, 12cm FOV] and T2: [2500/80/4,5mm thickness, 12cm FOV] weighted imaging, both lungs and heart were inflated, fixed (Heitzman's method) and embedded en bloc in collodion. MR images of the atelectatic portion were evaluated, and MRI findings of the atelectatic portion were correlated with pathologic findings.

RESULTS

MRI, especially T2 weighted images showed some characteristic signal patterns in each period. Correlations of these MRI features were performed with the pathologic findings: 1) The peripheral pulmonary parenchyma, on T2 weighted images showed signal increase with time which was attributed to edematous fluid retention in pulmonary alveoli. 2) The difference between inhomogeneous and homogeneous signal intensities on T2 weighted images on the 7th day was attributed to the patchy and even distribution of inflammatory process in pulmonary parenchyma. 3) On the 21st day, hypointensity bands were observed on T1 and T2 weighted images. These hypointensity bands were attributed to fibrotic changes in bronchial walls and nearby alveolar walls.

CONCLUSION

MR images well demonstrated pathological changes in atelectatic lungs caused by acute bronchial obstruction with time, suggesting the clinical usefulness of this approach.

The bacteriology of obstructive pneumonitis. A prospective study using ultrasound-guided transthoracic needle aspiration

Obstructive pneumonitis, the opacity that develops distal to an obstructing endobronchial lesion or external compression, is actually a combination of atelectasis, bronchiectasis with mucus plugging, and true parenchymal inflammation. In the majority of cases, it is usually not possible to determine whether infection is present or not from the radiographic findings alone. The aim of this study was to evaluate the bacteriology of obstructive pneumonitis and the influence of this result on the treatment of patients. From March 1992 to February 1993, 26 consecutive patients (20 men and six women) with obstructive pneumonitis were investigated. The obstructive pneumonitis had been caused by malignant tumors in 24 and benign lesions in two. Chest ultrasound (US) and US-guided percutaneous transthoracic aspirations were undergone to obtain specimens for microbiologic examination. Microorganisms were isolated from seven of nine febrile patients and two of 17 nonfebrile patients. A total of 16 bacterial strains are detected in obstructive pneumonitis (Pseudomonas aeruginosa, Klebsiella pneumoniae, viridant streptococci, Bacteroides fragilis, two Peptostreptococcus species, Mycobacterium tuberculosis, Pseudomonas maltophilia, Streptococcus sanguis, Staphylococcus aureus, Bacteroides thetaiotamomicrons, Bacteroides intermedius, Bacteroides species, Veillonella species, aerobic gram-positive bacilli, and Escherichia coli). In five cases the isolates were monobacteriae, and in the remaining four cases, cultures yielded more than one bacteria. The results of aspirate cultures led to changes in the initial antibiotic trial in seven of nine patients, and fever subsided thereafter. Pneumothorax occurred in one cases as the sole complication. The pathogen causing obstructive pneumonitis is very heterogeneous, and polymicrobial infection is common.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case report of rounded atelectasis on MRI]

A 73-year-old man was admitted to Toyama Red Cross Hospital, because of productive cough and right flank pain. His chest X-ray film and computed tomography (CT) showed pleural effusion and a mass shadow in the right lung area. On CT vessels and bronchi were seen curving toward the mass (comet tail sign), suggesting rounded atelectasis. Transthoracic lung biopsy under CT and echo guidance revealed suppurative pleuritis. MRI also showed the comet tail sign. Moreover, in the lesion, curling hypointense lines were observed on various slices. We describe how MRI facilitates the diagnosis of rounded atelectasis.

Fiberoptic bronchoscopy in the evaluation of carcinoma metastatic to the lung

To determine the clinical presentation of patients with malignancies metastatic to the lung, the diagnostic utility of fiberoptic bronchoscopy (FB), and the primary site of malignancies metastasizing endobronchially, we retrospectively reviewed 1,853 FB records (1987 to 1991) and selected 111 cases for review. Cases were divided on the basis of FB findings into abnormal (44 patients) and normal (67 patients). Pulmonary symptoms (cough, hemoptysis, and chest pain) prompted referral significantly more often in the abnormal FB group (34/44) than in the normal FB group (24/67). The finding of atelectasis on chest radiograph occurred more frequently in patients with endobronchial abnormalities. The spectrum of extrapulmonary malignancies that metastasize endobronchially has changed during the AIDS epidemic. Our study shows the most frequent causes of endobronchial mass lesions were Kaposi's sarcoma and the lymphoma group (Hodgkin's disease, nonHodgkin's lymphoma, chronic lymphocytic leukemia) and the most common malignancies causing submucosal metastases were breast and the lymphoma group. In summary, the highest yield from FB can be expected in patients experiencing symptoms of cough or hemoptysis and/or having radiographic evidence of atelectasis. We propose a new mnemonic "KLAS" (Kaposi's sarcoma, Lymphoma, Adenocarcinoma, Sarcoma) to describe the malignancies most likely to metastasize endobronchially in the 1990s.

[Osteochondroplastic tracheobronchopathy, osteochondromas and recurrent sinusitis. Apropos a case]

We describe the case of a patient with pneumonia presenting an atelectatic component at the front segment of the left upper Lobe (LUL) due to osteochondroplastic tracheobronchopathy (OT). The patient had been operated of an osteochondroma in the left perque and presented a proliferative bone lesion in the right femur suggesting the sam problem at this level. We discuss if that could be a casual association. We also analyze the potential relationship of OT and recurrent sinusitis, which was also present in this patient.

[Rounded atelectasis with emphasis on its wide spectrum]

While rounded atelectasis (RA) is considered to be rather common in the United States and Europe, the total number of RA cases reported from Japan still remains approximately 30. We have long been aware that there are many variations in the radiographic appearance of so-called RA and that RA has never been clearly defined. We retrospectively reviewed 22 cases collected as RA and its variants from several institutions. We defined RA as "peripheral atelectasis mimicking tumor secondary to shrinkage or bending of the pleura of various degrees, and accompanied by lung distortion." The diagnostic criteria of typical RA include (1) peripheral tumoral shadow in contact with pleural effusion or thickened pleura, (2) acute angle between the pleura and the shadow, (3) convergence of the pulmonary vessels and bronchi and (4) volume loss of the affected lobe. However, there are cases which lack some of these criteria but are considered to be included in the broad category of RA. We propose that RA should be considered to be an entity having a wide spectrum. Typical lesions showing "cranial tilting" of Hanke are on one side of the spectrum and small linear or strand shadows extending from the thickened pleura are on the other.

Three different mask physiotherapy regimens for prevention of post-operative pulmonary complications after heart and pulmonary surgery

OBJECTIVE

An investigation into the incidence of post-operative complications after thoracic surgery with 3 different physiotherapy masks.

DESIGN

A prospective, consecutive, randomized comparison.

SETTING

Department of Thoracic and Heart Surgery at a University Hospital. The treatments were performed by experienced and specially trained physiotherapists.

PATIENTS

160 patients were evaluated. 60 patients undergoing heart surgery, 59 patients having pulmonary resection, and 41 patients with exploratory thoracotomy.

INTERVENTIONS

In each operative category the patients were treated with one of three face mask systems used in addition to routine chest physiotherapy. These were either continuous positive airway pressure (CPAP), positive expiratory pressure (PEP), or inspiratory resistance - positive expiratory pressure (IR-PEP).

MEASUREMENTS AND RESULTS

Post-operative pulmonary complications were assessed by forced vital capacity (FVC), arterial oxygen tension (PaO2), and chest X-ray examination, all measured pre-operatively and on the fourth and ninth post-operative day. The patients filled in a questionnaire expressing their opinion about their mask treatment. There was an equal decrease in FVC, FVC%, and PaO2, and equal frequency of atelectasis in the 3 mask treatments. More patients with the PEP mask favoured their system than did those with the other 2 systems.

CONCLUSION

There was no statistically significant difference between the treatments: continuous positive airway pressure (CPAP), positive expiratory pressure (PEP), and inspiratory resistance - positive expiratory pressure (IR-PEP) on post-operative complications. Any of the three treatments may be used as supplement to standard chest physiotherapy.

CT and MR features of primary pulmonary hemangiopericytomas

We investigated the radiological findings of four patients with malignant pulmonary hemangiopericytomas, comparing plain chest radiography, CT, and MR. The radiographic presentation ranged from a small single lesion to a tumor almost completely occupying a hemithorax. Pathognomonic radiological features of malignant pulmonary hemangiopericytomas could not be established, but characteristic features include a large lobulated well-circumscribed mass with an encapsulated appearance, contrast enhancement of the margin, and no signs of surrounding compression atelectasis. The tumors were associated with late onset or a paucity of chest symptoms. Additional information regarding heterogeneity and effects on adjacent structures was provided by MR and was helpful in suggesting the diagnosis of malignant pulmonary hemangiopericytoma.

CT appearances of rounded atelectasis

Five patients examined with CT had lesions fulfilling criteria for a diagnosis of rounded atelectasis (RA) and these were managed without biopsy. In three patients unsuspected contralateral lesions were identified as RA variants, and one of these was biopsied at thoracotomy and proved to be benign. All patients remain well at 6-22 months follow-up. We concur with recent reports that there is a spectrum of CT appearances of RA and that even atypical lesions seldom need further investigation. We also suggest that the appearances of some atypical lesions add support for the fibrosing theory of pathogenesis of RA.

[A case of round atelectasis associated with spontaneous pneumothorax]

A 59-year-old female was admitted for spontaneous pneumothorax. After evacuation, the chest X-ray film showed a round mass lesion at the left hilum. Following curettage and bronchoalveolar lavage of the left B3c, the mass became smaller, suggesting the diagnosis of round atelectasis. This is the first report of round atelectasis complicated by spontaneous pneumothorax. The mechanism of this case is suggested to resemble that of round atelectasis associated with pleural effusion.

Positioning effects on arterial oxygen and relative pulmonary shunt in patients receiving mechanical ventilation after CABG

OBJECTIVE

To examine the effects of three different positions on arterial oxygen and relative pulmonary shunt in patients after coronary artery bypass graft (CABG) who are receiving mechanical ventilation with an effective tidal volume of 15 ml/kg and a minimum of 5 cm H2O positive end-expiratory pressure.

DESIGN

Repeated measures, counterbalanced.

SETTING

Adult cardiovascular intensive care unit in a major tertiary referral hospital.

SUBJECTS

Convenience sample of 30 patients who had undergone CABG, 90% of whom had postoperative atelectasis.

OUTCOME MEASURES

Partial pressure arterial oxygen (PaO2) and relative pulmonary shunt (areas of low ventilation-perfusion ratio).

INTERVENTION

Supine, right lateral, and left lateral positions with head of bed elevated 30 degrees.

RESULTS

No statistically significant differences in arterial oxygen and relative pulmonary shunt were found among the three positions.

CONCLUSIONS

For a selected cohort, positioning may not be an important consideration in arterial oxygenation in patients who have undergone CABG and are receiving mechanical ventilation with a high tidal volume and positive end-expiratory pressure.

[Fibro-bronchoscopy without general anesthesia in pediatric patients]

Flexible bronchofiberoscopy is at present an indispensable technique in pediatric pulmonology departments. The fact that it can be used outside of the operating theater without general anesthesia or additional oxygen has greatly increased its field of pediatric applications. Thirty-three fibrobronchioscopies were performed during a period of one year on a group of children under 14 years of age. The most common indications for the procedure were atelectasis (27.3%), recurrent pneumonia (15.1%) and a possible foreign body (15.1%). The most usual sedation (82%) was the combination of Diazepan with Ketamine. Sixteen patients did not require oxygen and only one suffered a serious complication. The benefit of this technique was shown since the treatment of 22 children (67%) was changed following this procedure.

Rounded atelectasis with pleuritis: diagnosis and surgical treatment

A 73-year-old male was admitted with a large rounded atelectasis with pleural effusion. The involved lung was refilled with air as soon as surgical decortication of the thickened visceral pleura covering it was performed. Surgical treatment is believed to be necessary when a large rounded atelectasis with pleural effusion persists for a long time, or when malignancy is not completely excluded.

Diagnosis and management of endobronchial tuberculosis

We examined the records of sixty-one patients (17 males and 44 females) with endobronchial tuberculosis (EBTB). Smear tests of acid-fast bacilli were positive in 42 cases and cultures of tubercle bacilli (TB) were positive in 57. The main findings of chest roentgenogram on admission were as follows: no abnormal findings in 8, atelectasis in 30, infiltration in 25, and cavitary lesions in 6. The localization and cross-sectional extension of lesions confirmed bronchoscopically were as follows: trachea in 15, with 3 circular lesions (CLs). Right (R-) main bronchus in 19 with 11 CLs, left (L-) main bronchus in 18 with 11 of CLs, R-truncus intermedius in 14 with 6 of CLs, R-upper lobar bronchus (UB) in 17 with 12 CLs, R-middle lobar bronchus in 14 with 11 of CLs, R-lower lobar bronchus (LB) in 6 with 2 CLs, L-UB in 10 with 7 CLs and L-LB in 3 with 2 CLs. All cases were treated by combination chemotherapy with isoniazid, rifampicin, streptomycin and/or ethambutol and the rate of negative conversion of TB was good, but most of circular lesions resulted in severe bronchial stenosis or complete obstruction during and after chemotherapy, and no improvement was seen in any of the atelectasis cases at the cessation of chemotherapy. We discuss the points of early diagnosis and management of EBTB.

CT fluid bronchogram: observation in postobstructive pulmonary consolidation

Twelve patients with bronchial obstruction secondary to either cancer or broncholith were evaluated with chest radiography and computed tomography (CT). Chest radiography showed nonspecific lobar consolidation (12 cases), bulging fissure (6 cases), and air bronchogram (1 case). CT revealed air bronchogram, CT angiogram sign, bulging fissure, and fluid bronchogram in all six cases with partial bronchial obstruction (except for absence of air bronchogram in one case). CT fluid bronchograms were also present in the remaining six cases with total bronchial obstruction. Because of the lobar atelectasis, bulging fissure was absent in all six of these patients. CT angiogram signs and air bronchograms were observed in only half of the patients. CT is, therefore, very useful in detailed evaluation of postobstructive pulmonary consolidation. We particularly stress that the term "CT fluid bronchogram" should be applied when the bronchi are filled with fluid instead of air.

[The magnetic resonance characteristics of rounded atelectasis]

Rounded atelectasis is a peculiar form of lung collapse which is well known by radiologists. Its appearance on conventional radiographs and CT is by now well recognized and widely reported. Even though these two techniques usually allow a diagnosis to be made, the MR appearance of rounded atelectasis is worth mentioning as well. This diagnostic imaging technique is widely employed, and our experience suggests that, in some cases, MR Imaging can give an important contribution to the study of this condition. We report our experience with 6 cases of rounded atelectasis in 5 patients (one patient had bilateral lesions). Five signs characteristic of rounded atelectasis were observed: some of them are seen on both conventional radiographs and CT scans, others are typical of the latter technique. All cases showed peripheral location of the lesions and the "comet tail" sign--i.e., vascular structures gently curving into the mass. These two signs are also observed on conventional radiographs and CT scans. Typical of MR imaging are the extant 3 signs: low signal in T1 and high signal in T2-weighted images in the whole of our cases; no signal from pleural thickening next to the mass in T2-weighted images, and, finally, the "kidney-like" pattern--i.e., hypointense lines converging toward the center of the mass. All these signs, which were always observed in our series, support the current etiopathogenetic hypothesis of pleural effusion as an early sign, which is reported to be followed by fibrous pleural involution which wraps atelectatic parenchyma up. On the basis of these typical MR features a correct diagnosis can usually be made even in those cases in which conventional radiography and CT do not allow a definite diagnosis.

Folded lung: a masquerader of malignancy

Four cases of folded lung were observed over an 8-year period up to 1990. Because of suspected malignancy, three patients underwent exploratory thoracotomy, without subsequent morbidity or mortality, but the fourth patient declined surgery. Although folded lung may have characteristic computed tomographic features, these may be mimicked by carcinoma. If the patient is fit enough, exploratory thoracotomy is advisable in order to establish the diagnosis and permit resection of the lesion, if indicated, while avoiding the risks entailed by false negative CT scan and needle biopsy.

Allergic bronchopulmonary aspergillosis caused by Aspergillus terreus presenting lobar collapse

A case of allergic bronchopulmonary aspergillosis (ABPA) is described which presents left upper lobe collapse caused by Aspergillus terreus, an organism rarely found in ABPA. It is unusual for initial radiographic findings of ABPA to include extensive collapse.