The phrenic nerve with accompanying vessels: a silent cause of cardiovascular border obliteration on chest radiography.
OBJECTIVE
Our aim was to clarify the frequency of cardiovascular border obliteration on frontal chest radiography and to prove that the phrenic nerve with accompanying vessels can be considered as a cause of obliteration of cardiovascular border on an otherwise normal chest radiography.


METHODS
Two radiologists reviewed chest radiographs and computed tomography (CT) images of 100 individuals. CT confirmed the absence of intrapulmonary or extrapulmonary abnormalities in all of them. We examined the frequency of cardiovascular border obliteration on frontal chest radiography and summarized the causes of obliteration as pericardial fat pad, phrenic nerve, intrafissure fat, pulmonary vessels, and others, comparing them with CT in each case.


RESULTS
Cardiovascular border was obliterated on frontal chest radiography in 46 cases on the right and in 61 on the left. The phrenic nerve with accompanying vessels was found to be a cause of obliteration in 34 of 46 cases (74%) on the right and 29 of 61 (48%) cases on the left. The phrenic nerve was the most frequent cause of cardiovascular border obliteration on both sides.


CONCLUSIONS
The phrenic nerve with accompanying vessels, forming a prominent fold of parietal pleura, can be attributed as a cause of cardiovascular border obliteration on frontal chest radiography.
Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
Shiri
S
Farhana
Department of Clinical Oncology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan. ashi@nagasaki-u.ac.jp.
Kazuto
K
Ashizawa
Department of Clinical Oncology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
Hideyuki
H
Hayashi
Department of Radiology, Nagasaki Prefecture Shimabara Hospital, 7895 Kawajiri, Shimabara, Nagasaki, 855-0861, Japan.
Yukihiro
Y
Ogihara
Department of Radiology, Nagasaki Memorial Hospital, 1-11-54 Fukahori, Nagasaki, 851-0301, Japan.
Nobuya
N
Aso
Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
Kuniaki
K
Hayashi
Department of Radiology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
Masataka
M
Uetani
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002319:Cardiovascular System / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010791:Phrenic Nerve / Q000000981:diagnostic imaging*; D013902:Radiography, Thoracic; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
Cardiovascular border; Computed tomography; Phrenic nerve; Radiograph; Thorax