Lymphoproliferative disorders after liver transplantation: imaging features.

BACKGROUND: To define the imaging features of lymphoproliferative disorders that occur after liver transplantation. METHODS: A retrospective review of 605 liver transplantations between 1985 and 1998 showed 20 patients with posttransplantation lymphoproliferative disorders (PTLDs). All relevant clinical, imaging, and pathologic findings were reviewed. RESULTS: PTLDs occurred in 13 men and seven women (mean age = 43.3 years, age range = 18-68 years). The time to diagnosis of disease ranged from 1.5 to 51 months (mean = 14 months) posttransplantation. Cervical, thoracic, or abdominal lymphadenopathy was seen in 11 patients (55%). A complex portal mass in five patients (25%) was the second most common manifestation of PTLD, ranging in size from 5 to 12 cm. Other findings included gastrointestinal tract involvement in three patients (15%) seen as a duodenal mass and diffuse wall thickening in one patient and large bowel thickening in two patients with preexisting inflammatory bowel disease. CONCLUSION: There is a wide spectrum of findings in lymphoproliferative disorder after liver transplantation. The presence of lymphadenopathy, a portal mass, or bowel thickening indicates a need for further investigation to reach a pathologic diagnosis.

Bronchiolitis obliterans after lung transplantation: appearance on expiratory minimum intensity projection images.

OBJECTIVE: Bronchiolitis obliterans can manifest as a mosaic pattern of lung attenuation on computed tomographic (CT) scans. This study was conducted to investigate image enhancement using expiratory minimum intensity projection images and to compare these with thin-section scans. METHODS: Eleven patients (21 transplanted lungs) with biopsy-proven bronchiolitis obliterans were studied. Ten 1-mm thin-section scans were acquired helically at the level of the carina after full expiration. Expiratory minimum intensity projection images 10 mm thick were generated from a multiplanar reconstruction of data. Two thoracic radiologists analyzed the images. RESULTS: In comparison with thin-section scans, expiratory minimum intensity projection images demonstrated a greater (in 17 lungs) or equal (in 4 lungs) percentage area of air trapping, with greater conspicuity (in all 21 lungs). Air trapping involved an average of 52% of the cross-sectional area of 1 lung. CONCLUSIONS: Air trapping due to bronchiolitis obliterans is accentuated by forced expiration; minimum intensity projection images improve the detection of differences in lung attenuation. Therefore, expiratory minimum intensity projection images are very useful in demonstrating the mosaic pattern of lung attenuation caused by bronchiolitis obliterans.

Correlation of chest radiographic findings with biopsy-proven acute lung rejection.

The purpose of this study was to determine the chest radiographic findings of acute rejection and the accuracy of chest radiography in making this diagnosis in patients undergoing lung transplantation. For each of 100 transbronchial biopsies performed on 25 lung transplant recipients (single lung in three, double lung in 22), chest radiographs obtained within 24 hours before the biopsy were reviewed retrospectively without knowledge of clinical or biopsy information. Transbronchial biopsy revealed 42 instances of acute rejection in 17 patients and 58 instances of no acute rejection (normal, n = 43; other processes, n = 15). All pulmonary parenchymal radiographic abnormalities were assessed. Acute rejection was associated with the presence of middle or lower lung reticular interstitial or airspace disease in 21 lungs (sensitivity = 0.50 [21/42]). This pattern was seen in 18 lungs without acute rejection (specificity = 0.69 [40/58]). There was no difference in the appearance of the lungs between grades 1 and 2 acute rejection. Normal lungs were noted in 20 instances of acute rejection (48%). The authors conclude that chest radiograph findings are abnormal in about 50% of instances of biopsy-proven acute rejection. Because the appearance of acute rejection is similar to that of other conditions, the diagnosis cannot be made accurately by chest radiography.

The value of late computed tomographic scanning in identification of vascular abnormalities after abdominal aortic aneurysm repair.

PURPOSE: The purpose of this study was to determine the prevalence of late arterial abnormalities after aortic aneurysm repair and thus to suggest a routine for postoperative radiologic follow-up examination and to establish reference criteria for endovascular repair. METHODS: Computed tomographic (CT) scan follow-up examination was obtained at 8 to 9 years after abdominal aortic aneurysm (AAA) repair on a cohort of patients enrolled in the Canadian Aneurysm Study. The original registry consisted of 680 patients who underwent repair of nonruptured AAA. When the request for CT scan follow-up examination was sent in 1994, 251 patients were alive and potentially available for CT scan follow-up examination and 94 patients agreed to undergo abdominal and thoracic CT scanning procedures. Each scan was interpreted independently by two vascular radiologists. RESULTS: For analysis, the aorta was divided into five defined segments and an aneurysm was defined as a more than 50% enlargement from the expected normal value as defined in the reporting standards for aneurysms. With this strict definition, 64.9% of patients had aneurysmal dilatation and the abnormality was considered as a possible indication for surgical repair in 13.8%. Of the 39 patients who underwent initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and six of these aneurysms (15.4%) were of possible surgical significance. Graft dilatation was observed from the time of operation (median graft size of 18 mm) to a median size of 22 mm as measured by means of CT scanning at follow-up examination. Fluid or thrombus was seen around the graft in 28% of the cases, and bowel was believed to be intimately associated with the graft in 7%. CONCLUSION: Late follow-up CT scans after AAA repair often show vascular abnormalities. Most of these abnormalities are not clinically significant, but, in 13.8% of patients, the thoracic or abdominal aortic segment was aneurysmal and, in 15.4% of patients who underwent tube graft placement, one of the iliac arteries was significantly abnormal to warrant consideration for surgical repair. On the basis of these findings, a routine CT follow-up examination after 5 years is recommended. This study provides a population-based study for comparison with the results of endovascular repair.

Helical CT applications in the thorax and abdomen.

The past few years have witnessed a massive explosion in clinical applications for computed tomography (CT) as a result of exponential advances in technology. Most clinical practitioners have a limited understanding of the complexities and dynamics of modern CT, and even many radiologists are unable to keep up with the rapid evolution in refinements. In this article, Dr Rappaport summarizes some of the most recent advances in use of helical, or spiral, CT to diagnose diseases of the thorax and abdomen.

Lymphoproliferative disorders after lung transplantation: imaging features.

PURPOSE: To define the imaging features of lymphoproliferative disorders that occur after lung transplantation. MATERIALS AND METHODS: In a retrospective review of the cases of 246 patients who had undergone lung transplantation (62 single- and 184 double-lung transplants) between 1987 and 1997, the authors found nine patients (seven men and two women, aged 16-59 years [mean, 42.2 years]) with posttransplantation lymphoproliferative disorders. All imaging, clinical, and pathologic findings pertaining to these disorders were reviewed. RESULTS: Eight of the nine patients had isolated intrathoracic disease. The most common abnormality (six patients) was the presence of multiple, well-defined pulmonary nodules. These nodules, when multiple, had basilar and peripheral predominance. Other abnormal features included hilar or mediastinal adenopathy (two patients), a consolidated upper lobe (one patient), a pleural mass (one patient), and bulky abdominal lymphadenopathy (one patient with pathologically proved Hodgkin lymphoma). Three patients had nodules with a surrounding area of ground-glass opacity (halo sign), and one patient had multiple ill-defined areas of centrilobular opacity. Air bronchograms were not often seen, and pleural effusions were absent. CONCLUSION: The presence of well-defined pulmonary nodules in a patient who has undergone lung transplantation should raise concern about the possibility of posttransplantation lymphoproliferative disorder. In such cases, performance of pathologic studies should be expedited.

Extrathoracic angiomyolipomas in lymphangioleiomyomatosis.

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disorder that affects women and can lead to serious respiratory impairment. Since Bourneville's tuberous sclerosis (TS) was first reported, the striking similarities between the two entities have led many to believe that LAM is a forme fruste of TS. This is suggested by reports that angiomyolipomas, rare tumours in themselves, are reported in 40-80% of TS patients and occur in 15-30% of LAM patients. A retrospective chart review was conducted of 14 patients that presented to our institution with a diagnosis of LAM. We sought to document the clinical manifestations, particularly the incidence and location of extrathoracic tumours, in order to further support the hypothesis that LAM is a forme fruste of TS. Twelve patients had premenopausal onset of symptoms and two postmenopausal. The diagnosis was confirmed histologically (n = 12) and/or by computed tomography (CT) scan of the thorax (n = 12). Imaging investigations revealed extrathoracic tumours in 12 of 14 patients (86%). Eight of the 14 patients (57%) had renal tumours consistent with angiomyolipomas (bilateral in five patients). Only one patient had renal symptoms (flank pain and haematuria). All had normal serum creatinine, one had a reduced creatinine clearance. Extrathoracic nonrenal tumours were discovered in the pancreas, adrenals and uterus, findings previously unreported in LAM. In summary, the incidence of extrathoracic tumours in lymphangioleiomyomatosis patients is much higher than previously reported in the literature. This increased association supports the theory that lymphangioleiomyomatosis and tuberous sclerosis represent part of a spectrum of a similar disease process.

The solitary pulmonary nodule. Is it malignant or benign?

Solitary pulmonary nodules are usually identified on routine chest radiographs in asymptomatic patients. Most nodules have a benign cause, but bronchogenic carcinoma, metastases, and other malignant processes are important causes as well and must be excluded in differential diagnosis. Plain chest radiography, computed tomography, and fine-needle aspiration biopsy are useful diagnostic tools. When a malignant cause cannot be ruled out, the patient's age, smoking history, and nodule size must be considered. Observation by serial radiographs may be the appropriate course for patients who are at low risk for malignancy. For moderate- and high-risk patients, an immediate and more invasive workup is indicated.

Are patients receiving amiodarone at increased risk for cardiac operations?

Amiodarone therapy has been implicated as a risk factor for cardiothoracic surgical procedures. In patients undergoing map-guided surgical procedures for the treatment of ventricular tachycardia, we compared the perioperative course of those receiving long-term amiodarone therapy (n = 36) versus that in those not receiving the drug (n = 31). The two groups were similar with respect to age, sex, presenting symptoms, functional class, extent of coronary artery disease, presence of a ventricular aneurysm, technique of ventricular tachycardia ablation, cross-clamp or pump time, the number of vessels grafted, the operative fluid balance, and a need for intraaortic balloon pump or inotropic agent support. In 5 patients receiving amiodarone, epinephrine was required to maintain a normal systemic vascular resistance and adequate arterial pressure. Postoperatively, 6 patients (17%) on amiodarone therapy suffered acute respiratory failure. In spite of aggressive therapy, 3 of these patients died. Only 1 patient not receiving amiodarone died of a stroke. We conclude that amiodarone therapy in patients undergoing open heart operations is associated with an increased risk of severe pulmonary complications (p = 0.03 by Fisher's exact test). Amiodarone therapy should be withheld in patients with ventricular tachycardia until they have been assessed as candidates for possible surgical intervention.

Congenital bronchopulmonary diseases in adults: CT findings.

Congenital lung disease is divided into two types: lesions that arise from the primitive foregut (i.e., bronchopulmonary malformations) and lesions that originate in the pulmonary vasculature. The latter often are detected early in life because of signs and symptoms or other serious associated anomalies. Conversely, many of the bronchopulmonary anomalies are asymptomatic and therefore are not discerned until adulthood. This essay illustrates the spectrum of CT findings of many congenital bronchopulmonary malformations that are seen in adults, including pulmonary agenesis, anomalous bronchial branching, bronchial atresia, foregut cysts, bronchopulmonary sequestration, and pulmonary arteriovenous malformations.

Evaluation of oral contrast agents for abdominal magnetic resonance imaging.

We evaluated the efficacy of six available oral contrast agents in improving visualization of bowel and surrounding structures on magnetic resonance imaging of the abdomen and pelvis. Five volunteers were examined without oral contrast (baseline) and, on separate occasions, after ingestion of 600-900 cc of two positive contrasts [12.5% weight-to-volume (w/v) corn oil emulsion (COE), Redi Cat (EZ-Em Corp., Westbury, NY) mixed with 1% ferric ammonium citrate (FAC)] and four negative contrasts [220%, 105%, 85%, 60% w/v barium sulfate (Liquid HD, Liquid Polybar Plus, HD 85, reconstituted EZ Pake; EZ-Em Corp., Westbury, NY)]. Spin-echo axial and coronal T1-weighted and axial T2-weighted images were obtained in the abdomen and pelvis. Three radiologists blindly graded the images for improved visualization of bowel and surrounding structures. Data were analyzed for statistical significance using the General Linear Models algorithm. In the upper abdomen (stomach, duodenum, liver, and pancreas), COE yielded the highest mean scores (p < .0001), followed by 220% w/v barium. For the lower abdomen (ileum, colon), 220% w/v barium yielded the highest scores (p < .0001) and COE was much worse. The higher density barium preparations (220% and 105% w/v) yielded higher scores than their lower density counterparts (85% and 60%). All contrasts improved visualization of the retroperitoneum and spleen, but no one agent was best. All agents tested are superior to no agent at all. For visualization of the upper abdomen, 12.5% COE performed best. For visualization of the lower abdomen, 220% w/v barium performed best. For concurrent evaluation of both areas with one agent, 220% w/v barium performed best.

Idiopathic dilatation of the thoracic venous system.

Isolated venous aneurysm is a rarely reported cause of a mediastinal mass. The authors describe a patient who demonstrated aneurysmal dilatation of the superior vena cava, the left innominate vein, the azygos and the hemiazygos veins and the left inferior pulmonary vein after blunt chest trauma. This case emphasizes the value of computed tomography in the diagnosis of this complex, presumably congenital entity.

The value of barium as a gastrointestinal contrast agent in MR imaging: a comparison study in normal volunteers.

Preliminary data suggest that barium sulfate suspension is a potentially useful negative gastrointestinal contrast agent for MR imaging. To evaluate this hypothesis in a controlled fashion, abdominal and pelvic MR studies of 10 normal volunteers were performed before and after both oral (600-900 ml) and rectal (400 ml) administration of barium. Standard spin-echo coronal T1-, axial T1-, proton density-, and T2-weighted images were obtained at 1.5 T. Images obtained were randomized and interpreted by three observers, who evaluated bowel visualization and delineation of normal anatomy. Bowel segments evaluated were stomach, duodenum, proximal small bowel, proximal colon, distal colon, and rectum. Anatomic structures examined were pancreatic head, pancreatic body, pancreatic tail, retroperitoneum, spleen, liver, pelvic side walls, uterus, vagina, bladder, prostate, and seminal vesicles. Data concerning barium tolerance and safety were recorded. Descriptive, percent change, and kappa statistics were analyzed. Pairwise agreement techniques and repeated measures analysis of variance were performed. This statistical assessment showed a significant improvement in both bowel visualization (59-123% improvement, depending on the segment) and delineation of normal anatomy (23-68% improvement, depending on the structure) after barium administration, particularly on T1-weighted images. In addition, barium was a well-tolerated and safe contrast agent that did not produce artifacts. Our results show that barium sulfate is a useful negative gastrointestinal contrast agent for MR because it improves bowel visualization and delineation of abdominal anatomy, particularly on T1-weighted sequences.

Pulmonary lymphangioleiomyomatosis: high-resolution CT findings in four cases.

Lymphangioleiomyomatosis is a rare disease of unknown cause that affects women of reproductive age. It is characterized by progressive proliferation of smooth muscle in the lung. The patients present with progressive shortness of breath, pneumothorax, chylous effusion, and hemoptysis. Four patients with biopsy-proved lymphangioleiomyomatosis of the lung were evaluated using high-resolution CT. In all patients, the scan showed well-defined cystic air spaces, surrounded by uniformly thin walls, distributed diffusely throughout both lungs. The cystic air spaces ranged in size from a few millimeters to 5 cm. Pathologically, these cysts were predominantly bounded by normal-looking parenchymal components, with occasional patchy involvement by a smooth-muscle proliferative process. The CT appearance of lymphangioleiomyomatosis differs quite distinctly from that of other diseases that can cause cystic air spaces, such as fibrosing alveolitis, neurofibromatosis, and bronchiectasis, and less distinctly from pulmonary emphysema and eosinophilic granuloma. Our experience in these few cases suggests that the high-resolution CT findings in lymphangioleiomyomatosis are characteristic of the disease.

Cyclosporine-induced lymphoma following a unilateral lung transplant. The Toronto Lung Transplant Group.

Lymphomas are a well-known complication of therapy following organ transplantation. To date we have seen one lymphoma develop in a group of 24 patients who have undergone single or double lung transplantation. We report a 16-year-old man who developed multiple, rapidly appearing pulmonary nodules four months following transplantation. The Epstein-Barr virus and immunosuppressant drugs such as cyclosporine A have been implicated in the pathogenesis of this patient's rapidly progressive and fatal course.

Single-lung transplantation: imaging features.

The imaging studies obtained after single-lung transplantation in 14 patients were reviewed. The reimplantation response occurred in 13 patients and was an early, transient process, which varied in its manifestations from a subtle perihilar haze to dense consolidation with air bronchograms. Nine episodes of acute rejection, an imprecise clinical diagnosis, occurred in eight of the patients. The associated chest radiographic changes were variable and included basal or diffuse reticular interstitial disease in three cases and basal and/or perihilar consolidation in three cases; no change was detected in three cases. On four occasions, the radiographic changes resolved within 24 hours of intravenous corticosteroid administration. The radiographic findings associated with the reimplantation response and rejection were nonspecific and could have been mistaken for those of fluid overload, atelectasis, mucous plugging, and pneumonia. Bronchial dehiscence was well demonstrated by the finding at computed tomography of extraluminal air adjacent to the bronchial anastomosis. One patient developed multiple pulmonary nodules due to cyclosporine-induced lymphoma.