Ultrasonography for preoperative localization of enlarged parathyroid glands in secondary hyperparathyroidism.
OBJECTIVE
Parathyroidectomy (PTx) is sometimes performed to treat secondary hyperparathyroidism (2HPT) related to long-term dialysis. In this procedure, all four parathyroid glands should be resected. However, in patients with 2HPT, the four glands are not uniformly enlarged; therefore, preoperative diagnosis is difficult in comparison with primary hyperparathyroidism. We compared glands detected on preoperative ultrasonography (US) with those resected during PTx to examine the usefulness and limitations of US.


METHODS
The subjects were 44 patients with 2HPT who underwent PTx between December 2003 and November 2007. Surgery was indicated for patients meeting the following three conditions: a serum intact PTH (iPTH) level of 500 pg/ml or more; a maximum glandular volume of 500 mm3 or more; and increased bone metabolism. Before surgery, we detected the parathyroid glands using US, and three-dimensionally measured their sizes. PTx was performed based on US diagnosis, and resected glands were weighed.


RESULTS
Assuming that four parathyroid glands are present in each patient, the total number of glands in the 44 patients was 176. Of the 176 glands, 139 were detected on preoperative US. However, 27 could not be resected. Therefore, the detection rate on US was 63.6% (112/176). Of 37 glands that could not be detected on preoperative US, 30 were detected during surgery, and resected. There was a positive correlation between the glandular volume measured on US and isolated gland weight. However, there was no correlation between the preoperative serum iPTH level and the sum of the four isolated gland weights.


CONCLUSIONS
On preoperative US, approximately 80% of the glands were detected. However, the misdiagnosis rate was approximately 20%. The rate of accurate diagnosis was 63.6%. Even when glands were misdiagnosed or could not be confirmed on preoperative US, approximately 80% of them could be detected and resected during surgery. It may be impossible to estimate the glandular volume based on the preoperative serum iPTH level.
Kawata
Ryo
R
Department of Otolaryngology, Osaka Medical College, 2-7 Daigaku-Cho Takatsuki, Osaka 569-8686, Japan. oto034@poh.osaka-med.ac.jp
Kotetsu
Lee
L
Takamaki
Atsuko
A
Yoshimura
Katsuhiro
K
Takenaka
Hiroshi
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010280:Parathyroid Glands / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood; D016105:Parathyroidectomy; D011300:Preoperative Care; D014463:Ultrasonography
D010281:Parathyroid Hormone