Congenital and acquired abnormalities may alter the anatomy, size, or position of the azygos system. Computed tomography is often able to depict these abnormalities and in many cases indicate the cause. In this article, the normal anatomy of the azygos system is discussed and examples of congenital and acquired abnormalities are presented.
Fig. i -Anatomy.The roots enter the supraclavicular fossa by passing between the anterior and middle scalene muscles with the subclavian artery. These form three trunks near the lateral margin of the scalene muscles. The trunks travel superior and posterIor to the subclavian artery through the supraclavlcular fossa, separating into three antenor and three posterior divisions at the level of the clavicle. As the plexus crosses the first rib, the divisions form lateral, posterior, and medial cords. The terminal branches form at the lateral border of the pectoralIs minor muscle.
Eleven women with a history of infertility and uterine leiomyomas underwent magnetic resonance (MR) imaging of the pelvis prior to myomectomy. Nine also underwent preoperative pelvic ultrasonography (US), and ten underwent hysterosalpingography. All studies were interpreted prospectively by independent observers. With each imaging modality, the location (one of 11 anatomic segments), size, and appearance of detected uterine leiomyomas were determined and compared with surgical and histologic findings. Among the nine patients who underwent both MR and US, the sensitivity (85%) and accuracy (94%) of MR imaging for abnormal segments was significantly better than that of US (sensitivity = 69%, P = .015; accuracy = 87%, P = .043). For the ten patients who underwent both MR and hysterosalpingography, the sensitivity (91%) and accuracy (96%) of MR imaging was better than that of hysterosalpingography (sensitivity = 18%, P = .0005; accuracy = 72%, P = .0005). The specificities of the three modalities did not significantly differ (100%, 97%, and 98% for MR, US, and hysterosalpingography, respectively). These data suggest that MR imaging is superior to US or hysterosalpingography for preoperatively locating uterine leiomyomas.
Ultrasound-guided fine needle aspiration (USG-FNA) is a safe, effective, and dependable test used to assess thyroid nodules. However, the size of the lesion can adversely affect the outcome of the procedure. The aim of this study was to assess specimen adequacy and diagnostic specificity in USG-FNA of thyroid nodules measuring < or = 1.5 cm. A total of 219 thyroid FNAs were performed in a one year; 26 were obtained by pathologists, 139 by clinicians, and 54 by radiologists under ultrasound guidance. Of the 54 ultrasound-guided aspirates, 19 cases (35%) were performed on nodules < or = 1.5 cm (range 0.8-1.5 cm, mean 1.3 cm). Cytologic material from these 19 cases was reviewed along with corresponding available follow-up surgical material. Standard criteria for specimen adequacy and established morphologic criteria for diagnostic specificity were assessed in each case. All 19 cases met criteria for specimen adequacy, and in 17 cases (89%) specific cytologic diagnoses were made (cellular/adenomatous nodule--2 cases, colloid nodule--10 cases, Hashimoto's thyroiditis--4 cases, and papillary cystic carcinoma--1 case). The diagnoses were confirmed by surgical follow-up in six cases including the case of papillary carcinoma. One case diagnosed as suspicious for a papillary carcinoma subsequently was found to be a follicular adenoma by histology. In one case, a diagnosis of lymphocytic thyroiditis versus intrathyroidal lymphoid tissue was made (See Table I). In majority of cases of USG-FNA of nonpalpable thyroid nodules, adequate material may be obtained for a specific cytopathologic diagnosis.
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