MRI and CT findings of metastatic pulmonary calcification

Metastatic Pulmonary Calcification: Single-Center Review of Typical and Atypical Imaging Features

PURPOSE

The purpose of this study is to bring attention to an atypical form of metastatic pulmonary calcification, which is conventionally described as a metabolic process with upper lobe predominance in patients with a specific clinical history, which has not been reported as a distinct entity.

METHODS

Patients with metastatic pulmonary calcification (MPC) were first identified with mPower keyword search, including MPC or metastatic calcifications on computed tomography chest radiological reports. Patients were then filtered on likelihood of MPC based off imaging reports. Images were then reviewed by three senior radiologists for pertinent characteristics such as location of MPC, degree of calcifications and pleural effusions. Based on the predominant location of MPC, cases were labeled as either typical or atypical. Clinical and imaging characteristics relevant to MPC were noted and compared across typical and atypical cases.

RESULTS

In our study, we describe 25 patients with MPC, 13 defined as typical MPC and 12 with atypical MPC. Through consensus of senior radiologists, MPC was deemed to be mild (52%), moderate (44%), or severe (4%). Twenty-three patients (92%) had underlying renal disease including 21 requiring dialysis at the time of diagnosis. Outside of age at diagnosis, there was no significant clinical difference between the two groups. Evaluation of imaging characteristics (average HU attenuation, 267; range, 186-295), pattern and distribution of calcification, and clinical history strongly supported a diagnosis of atypical MPC.

CONCLUSION

This study presents several cases of lower lobe subpleural MPC associated with pleural effusions, which has not been reported as a distinct entity, despite comprising a significant portion of MPC cases at our institution.

Metastatic pulmonary calcification mimicking pulmonary tuberculosis: A case report

Metastatic pulmonary calcification (MPC) is characterized by deposition of calcium in the normal lung parenchyma secondary to elevation of serum calcium. Most patients are asymptomatic and routine chest radiograph is not sensitive to make the diagnosis. Further imaging is needed such as computed tomography (CT) which typically shows small centrilobular nodules in the upper lobes. We report a case of a 30‐year‐old woman with end stage kidney disease who was diagnosed with pulmonary tuberculosis which was then revised to metastatic pulmonary calcification. The CT thorax feature for this patient was atypical for metastatic pulmonary calcification where it demonstrated tree‐in‐bud nodules suggestive of infection. The final diagnosis was made based on bronchoalveolar lavage which was culture‐negative for Mycobacterium and transbronchial lung biopsy demonstrating calcium deposition in the interstitium.

Thoracic calcifications on magnetic resonance imaging: correlations with computed tomography

OBJECTIVE

To identify the characteristics of thoracic calcifications on magnetic resonance (MR) imaging, as well as correlations between MR imaging and CT findings.

METHODS

This was a retrospective study including data on 62 patients undergoing CT scans and MR imaging of the chest at any of seven hospitals in the Brazilian states of Rio Grande do Sul, São Paulo, and Rio de Janeiro between March of 2014 and June of 2016 and presenting with calcifications on CT scans. T1- and T2-weighted MR images (T1- and T2-WIs) were semiquantitatively analyzed, and the lesion-to-muscle signal intensity ratio (LMSIR) was estimated. Differences between neoplastic and non-neoplastic lesions were analyzed.

RESULTS

Eighty-four calcified lesions were analyzed. Mean lesion density on CT was 367 ± 435 HU. Median LMSIRs on T1- and T2-WIs were 0.4 (interquartile range [IQR], 0.1-0.7) and 0.2 (IQR, 0.0-0.7), respectively. Most of the lesions were hypointense on T1- and T2-WIs (n = 52 [61.9%] and n = 39 [46.4%], respectively). In addition, 19 (22.6%) were undetectable on T1-WIs (LMSIR = 0) and 36 (42.9%) were undetectable on T2-WIs (LMSIR = 0). Finally, 15.5% were hyperintense on T1-WIs and 9.5% were hyperintense on T2-WIs. Median LMSIR was significantly higher for neoplastic lesions than for non-neoplastic lesions. There was a very weak and statistically insignificant negative correlation between lesion density on CT and the following variables: signal intensity on T1-WIs, LMSIR on T1-WIs, and signal intensity on T2-WIs (r = -0.13, p = 0.24; r = -0.18, p = 0.10; and r = -0.16, p = 0.16, respectively). Lesion density on CT was weakly but significantly correlated with LMSIR on T2-WIs (r = -0.29, p < 0.05).

CONCLUSIONS

Thoracic calcifications have variable signal intensity on T1- and T2-weighted MR images, sometimes appearing hyperintense. Lesion density on CT appears to correlate negatively with lesion signal intensity on MR images.

Metastatic Pulmonary Calcification with Coexisting Non-specific Interstitial Pneumonia: A Rare Case Report and Literature Review

Patients with underlying chronic kidney disease (CKD) often have elevated serum calcium and parathyroid hormones due to compromised kidney function. We present a case of a 63-year-old female non-smoker with a surgical history of three renal transplants (at age 47, 51, and 58) along with thyroidectomy and parathyroidectomy, who came to the emergency department with complaints of a persistent dry cough and shortness of breath for the last two months. The patient had been on immunosuppressive drugs-tacrolimus, prednisolone, and mycophenolic acid-since her first renal transplant as well as on cinacalcet after parathyroidectomy (at age 54). An initial computed tomography (CT) scan demonstrated ground glass opacities in the bilateral upper lobes while bronchoscopy revealed few inflammatory cells without any fungi or bacteria. A repeat CT scan performed five days later due to rapid progression of her clinical symptoms showed worsening of ground glass opacities in the bilateral upper lobes and new nodules in the right middle and lower lung lobes. A wedge lung biopsy revealed metastatic pulmonary calcification (MPC) in the right upper lobe and non-specific interstitial pneumonia (NSIP) in the right lower lobe, confirming the co-existence of two different pathological processes most likely complicating the patient's clinical symptoms. Despite comprehensive medical therapy, the patient's symptoms progressively worsened and she is currently undergoing evaluation for both renal and lung transplants. Our case report not only presents a rare case of MPC coexisting with NSIP but also sheds light on the associated morbidity due to pulmonary symptoms in CKD patients.

Metastatic pulmonary calcification: Experience from a single center in Singapore

Metastatic pulmonary calcification (MPC) was seen in 79% of patients with end-stage renal disease (ESRD) during autopsy. However, it is not commonly diagnosed in vivo. Its pathogenesis is not fully understood. We report a retrospective series of 5 cases of MPC from a single center in Singapore. MPC were diagnosed using radiological or histological features. Mean onset of MPC from diagnosis of ESRD was 22.6 ± 3.1 years. One patient remains asymptomatic. Four patients died, one was related to MPC. All patients had calcifications at the lung apices on radiological studies. Three patients with MPC were diagnosed based on radiological features while 2 had histological features. Four patients underwent parathyroidectomy without radiological changes before parathyroidectomy. Median intact parathyroid hormone of this series was 5.6 pmol/L (IQR 1.3-139.4), alkaline phosphatase 74 U/L (IQR 62-461), calcium 2.10 mmol/L (IQR 1.85-2.40), and phosphate 1.30 mmol/L (IQR 0.87-1.63). The observed low iPTH suggests that MPC might occur in low iPTH. Our case series showed MPC might occur in low iPTH after parathyroidectomy, in contrast to existing literature that suggests MPC is diagnosed in patients with elevated iPTH. Parathyroidectomy does not prevent MPC.

Metastatic pulmonary calcification: high-resolution computed tomography findings in 23 cases

Objective

The aim of this study was to evaluate the high-resolution computed tomography (HRCT) findings in patients diagnosed with metastatic pulmonary calcification (MPC).

Materials and Methods

We retrospectively reviewed the HRCT findings from 23 cases of MPC [14 men, 9 women; mean age, 54.3 (range, 26-89) years]. The patients were examined between 2000 and 2014 in nine tertiary hospitals in Brazil, Chile, and Canada. Diagnoses were established by histopathologic study in 18 patients and clinical-radiological correlation in 5 patients. Two chest radiologists analyzed the images and reached decisions by consensus.

Results

The predominant HRCT findings were centrilobular ground-glass nodules (n = 14; 60.9%), consolidation with high attenuation (n = 10; 43.5%), small dense nodules (n = 9; 39.1%), peripheral reticular opacities associated with small calcified nodules (n = 5; 21.7%), and ground-glass opacities without centrilobular ground-glass nodular opacity (n = 5; 21.7%). Vascular calcification within the chest wall was found in four cases and pleural effusion was observed in five cases. The abnormalities were bilateral in 21 cases.

Conclusion

MPC manifested with three main patterns on HRCT, most commonly centrilobular ground-glass nodules, often containing calcifications, followed by dense consolidation and small solid nodules, most of which were calcified. We also described another pattern of peripheral reticular opacities associated with small calcified nodules. These findings should suggest the diagnosis of MPC in the setting of hypercalcemia.

Chest magnetic resonance imaging: a protocol suggestion

In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI) has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation.

Metastatic pulmonary calcification misdiagnosed as a fungal infection: A case report

Metastatic pulmonary calcification is a rare lesion, characterized by calcium salt depositing in normal lung tissue. The clinical profile of a case of metastatic pulmonary calcification following renal transplantation was described. A computed tomography scan of the chest revealed ground-glass opacities in bilateral lungs and a node exhibiting a halo in the right upper lobe, which were suspected aspergillus infection. Following examination and therapy, the results of lung biopsy revealed metastatic pulmonary calcification. Although metastatic pulmonary calcification was reported in renal failure patients previously, metastatic pulmonary calcification with cavity lesions has never, to the best of our knowledge, been previously reported. The aim of the present report was to improve the understanding of metastatic pulmonary calcification.

AS, Zanetti G, Marchiori E. Can chest high-resolution computed tomography findings diagnose pulmonary alveolar microlithiasis?

OBJECTIVE

The present study was aimed at retrospectively reviewing high-resolution computed tomography (HRCT) findings in patients with pulmonary alveolar microlithiasis in order to evaluate the frequency of tomographic findings and their distribution in the lung parenchyma.

MATERIALS AND METHODS

Thirteen patients (9 females and 4 males; age, 9 to 59 years; mean age, 34.5 years) were included in the present study. The HRCT images were independently evaluated by two observers whose decisions were made by consensus. The inclusion criterion was the presence of abnormalities typical of pulmonary alveolar microlithiasis at HRCT, which precludes lung biopsy. However, in 6 cases lung biopsy was performed.

RESULTS

Ground-glass opacities and small parenchymal nodules were the predominant tomographic findings, present in 100% of cases, followed by small subpleural nodules (92.3%), subpleural cysts (84.6%), subpleural linear calcifications (69.2%), crazy-paving pattern (69.2%), fissure nodularity (53.8%), calcification along interlobular septa (46.2%) and dense consolidation (46.2%).

CONCLUSION

As regards distribution of the lesions, there was preferential involvement of the lower third of the lungs. No predominance of distribution in axial and anteroposterior directions was observed.

Pulmonary calcifications: a pictorial review and approach to formulating a differential diagnosis

Pulmonary calcifications encompass a wide range of causes, both common and rare, such as calcified pulmonary nodules from chronic fungal infections and pulmonary alveolar microlithiasis. In this pictorial review, we categorize them based on etiology, which includes neoplastic calcifications, nonneoplastic calcified nodules, and iatrogenic- and exposure-related causes of pulmonary calcifications. We also illustrate the most characteristic imaging findings and outline the clinical implications for each of these entities to provide a sensible approach to pulmonary calcifications.

Metastatic pulmonary calcification: state-of-the-art review focused on imaging findings

Metastatic pulmonary calcification (MPC) is a subdiagnosed metabolic lung disease that is commonly associated with end-stage renal disease. This interstitial process is characterized by the deposition of calcium salts predominantly in the alveolar epithelial basement membranes. MPC is seen at autopsy in 60-75% of patients with renal failure. It is often asymptomatic, but can potentially progress to respiratory failure. Chest radiographs are frequently normal or demonstrate confluent or patchy airspace opacities. Three patterns visible on high-resolution computed tomography have been described: multiple diffuse calcified nodules, diffuse or patchy areas of ground-glass opacity or consolidation, and confluent high-attenuation parenchymal consolidation. The relative stability of these pulmonary infiltrates, in contrast to infectious processes, and their resistance to treatment, in the clinical context of hypercalcemia, are of diagnostic value. Scintigraphy with bone-seeking radionuclides may demonstrate increased radioactive isotope uptake. The resolution of pulmonary calcification in chronic renal failure may occur after parathyroidectomy, renal transplantation, or dialysis. Thus, the early diagnosis of MPC is beneficial. The aim of this review is to describe the main clinical, pathological, and imaging aspects of MPC.

Calcificação pulmonar metastática: relato de caso

Neste trabalho é relatado o caso de uma paciente do sexo feminino de 48 anos de idade, portadora de insuficiência renal crônica, em diálise há 13 anos, tendo iniciado o quadro com hemoptise, febre, tosse produtiva e dispneia aos grandes esforços. A radiografia de tórax apresentou opacidades mal definidas predominando nos terços médios e inferiores dos pulmões. A tomografia computadorizada de tórax evidenciou opacidades em vidro fosco associadas com nódulos centrolobulares mal definidos, com atenuação em vidro fosco. A paciente foi submetida a lavagem broncoalveolar, que foi negativa para micobactérias e fungos. Com base nesses achados, foi realizada biópsia pulmonar a céu aberto, que revelou calcificação pulmonar metastática.