title: Evaluation of breath-hold 201Tl SPECT in the differential diagnosis of solitary pulmonary nodules.
abstract: The aim of this study was to evaluate the usefulness of deep inspiration breath-hold SPECT (BrST, a method for 201Tl SPECT) in the diagnosis of solitary pulmonary nodules (SPN).
  
  
  METHODS
  Ten patients with malignant lesions and five with benign lesions were enrolled in this study. Early SPECT acquisition was performed 15 min after injection of 201Tl, while delayed SPECT images were acquired 3 h after injection. The first 15-sec acquisition was done using the BrST technique, and the second with the conventional free breathing (FB) method. We performed this technique alternately, and therefore, the odd data were from BrST and the even data were from FB. We referred to the T/N ratio of the early images as the ER and to the T/N ratio of the delayed images as the DR. To semi-quantitatively evaluate the degree of retention in the lesion, the retention index (RI) was calculated.
  
  
  RESULTS
  The RI of BrST indicated greater accuracy than that of FB in the differential diagnosis of SPN. For the benign and malignant lesions, the RI of BrST was -3.07 +/- 31.51 and 29.86 +/- 25.01, respectively (p < 0.05). The sensitivity, specificity, and accuracy of BrST (80%, 80%, and 80%, respectively) were significantly higher than those of FB (p < 0.05).
  
  
  CONCLUSIONS
  The BrST method is more accurate than that of the conventional FB method in the differential diagnosis of SPN.
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan. rad031@poh.osaka-med.ac.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Komori
authors.forename: Isamu
authors.initials: I
authors.lastname: Narabayashi
authors.forename: Masuo
authors.initials: M
authors.lastname: Hayashi
authors.forename: Shoji
authors.initials: S
authors.lastname: Horiuchi
authors.forename: Itaru
authors.initials: I
authors.lastname: Adachi
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Ogura
authors.forename: Hitoya
authors.initials: H
authors.lastname: Ohta
authors.forename: Keita
authors.initials: K
authors.lastname: Utsunomiya
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009068:Movement; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012119:Respiration; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium