Emergency department CT screening of patients with nontraumatic neurological symptoms referred to the posterior fossa: comparison of thin versus thick slice images.

Evaluation of the posterior fossa (PF) on 5-mm-thick helical CT images (current default) has improved diagnostic accuracy compared to 5-mm sequential CT images; however, 5-mm-thick images may not be ideal for PF pathology due to volume averaging of rapid changes in anatomy in the Z-direction. Therefore, we sought to determine if routine review of 1.25-mm-thin helical CT images has superior accuracy in screening for nontraumatic PF pathology. MRI proof of diagnosis was obtained within 6 h of helical CT acquisition for 90 consecutive ED patients with, and 88 without, posterior fossa lesions. Helical CT images were post-processed at 1.25 and 5-mm-axial slice thickness. Two neuroradiologists blinded to the clinical/MRI findings reviewed both image sets. Interobserver agreement and accuracy were rated using Kappa statistics and ROC analysis, respectively. Of the 90/178 (51 %) who were MR positive, 60/90 (66 %) had stroke and 30/90 (33 %) had other etiologies. There was excellent interobserver agreement (κ > 0.97) for both thick and thin slice assessments. The accuracy, sensitivity, and specificity for 1.25-mm images were 65, 44, and 84 %, respectively, and for 5-mm images were 67, 45, and 85 %, respectively. The diagnostic accuracy was not significantly different (p > 0.5). In this cohort of patients with nontraumatic neurological symptoms referred to the posterior fossa, 1.25-mm-thin slice CT reformatted images do not have superior accuracy compared to 5-mm-thick images. This information has implications on optimizing resource utilizations and efficiency in a busy emergency room. Review of 1.25-mm-thin images may help diagnostic accuracy only when review of 5-mm-thick images as current default is inconclusive.

Location as an important predictor of lymph node involvement for pulmonary adenocarcinoma.

BACKGROUND: Increasing data implicate histologic grade and radiographic appearance along with tumor size as key prognostic indicators for pulmonary adenocarcinoma. The impact of tumor location on prognosis has not been examined. METHODS: The records of 530 consecutive patients with pulmonary adenocarcinoma pathologically staged between June 1979 and July 2002 were reviewed. All patients had a preoperative computed tomographic scan of the chest and underwent surgical staging by mediastinoscopy, lymph node sampling, or lymph node dissection. Patients with bronchioalveolar cell carcinoma were excluded. Peripheral tumors were compared with central tumors with regard to stage and survival. A tumor was considered to be central if visualized within the inner third of the lung field or seen bronchoscopically. Patients with T1 cancers were further analyzed on the basis of tumor size. Survival was determined by the Kaplan-Meier analysis and comparisons were made by the log-rank method. RESULTS: Central tumors were more advanced and demonstrated a significantly (P < .0001) poorer survival than peripheral tumors (median 18 vs 39 months). Sixty percent of patients with central tumors had stage III or stage IV disease compared with 25% of those with peripheral tumors. Central T1 tumors, however, demonstrated a 50% incidence of lymph node involvement. Although the incidence of lymph node metastases increased incrementally with the size of peripheral T1 tumors, it remained 50% for central T1 tumors irrespective of size. CONCLUSION: Tumor location for pulmonary adenocarcinoma should be considered when planning therapy. Central tumors have a high incidence of lymph node metastases (regardless of size) and a poorer prognosis.