Australasian radiology最新文献

The authors have assessed the role of computerized three-dimensional (3-D) and traditional (TD) radiotherapy planning and inhomogeneity corrections in improving target volume coverage and normal tissue sparing in carcinoma of the tongue. Coverage of target volumes in 3-D versus TD plans revealed the following. Volume receiving 95% of dose, clinical target volume (CTV): 1-68% versus 0-24%; gross tumour volume-lymph nodes (GTV-l): 0-80% versus 0-20%; gross tumour volume-primary tumour (GTV-II): 0-65% versus 0-26%. Dose to 95% of target volume CTV 77-92% versus 76-87%; GTV-I: 81-90% versus 61-88%; GTV-II: 82-93% versus 68-87%. Minimum dose to 5% of target volume, CTV: 77-93% versus 74-81%; GTV-I: 81-90% versus 61-88%; GTV-II: 76-93% versus 68-87%. Minimum dose to a volume of no less than 5% of the target volume, CTV: 93-98% versus 88-96%; GTV-I: 87-100% versus 88-97%; GTV-II: 86-98% versus 88-96%. A new parameter (inhomogeneity difference) was devised to study target volume dose homogeneity and was found to be very useful. Dose to two-thirds of the parotid glands in 3-D versus TD plans showed a mean of 46 versus 65% for right parotid glands and 44 versus 56% for left parotid glands in all patients. Better tumour dose homogeneity, increased mean tumour dose, avoidance of geographic misses and better parotid sparing was achieved in 3-D plans as compared to TD plans. We could not demonstrate any role for inhomogeneity corrections using currently available computerized dose algorithms.

A case of tubular carcinoma within a radial scar pattern is reported. The aim of this study is to support the opinion of the authors who believe that there is a relationship between tubular carcinoma and radial scar. We think that surgical biopsy should be recommended in all cases of stellate lesions detected at mammography.

A retrospective study of large-gauge core biopsy (LGCB) of 206 non-palpable mammographic abnormalities detected at routine screening in a community-based clinic accredited with the Australian National Program for the Early Detection of Breast cancer, was performed to ascertain the role of LGCB as an alternative to diagnostic surgical biopsy within such a programme. Of the 51 malignancies diagnosed by LGCB and proceeding to treatment, no false-positives were found and agreement as to the presence, or otherwise, of invasion between core and open biopsy was 95%. Once malignancy was established by LGCB, one-stage treatment was possible in 74.5% of cases. A total of 114 lesions were considered to be benign and returned to routine screening. One interval cancer subsequently developed in this group. Incongruity between the pathological diagnosis from core biopsy and the mammographic image occurred in 29 cases, representing potential mistargeting in 14.1% of cases. Four cancers were discovered in this group when the patients subsequently proceeded to surgical biopsy, making an overall false-negative rate of 2.4%. No core biopsy sample was considered inadequate for pathological assessment and no lesion proved inaccessible to targeting. There was no long-term morbidity. We believe that LGCB is a safe, reliable and cheaper alternative to diagnostic surgical biopsy, but a close correlation of pathology and mammography is required to avoid the erroneous return of women to routine recall.

A 54-year-old man with a unilocular hydatid cyst within the infero-posterior angle of the orbit and a 6-year-old male child with a unilocular hydatid cyst within the supero-medial angle of the orbit are presented. The retrobulbar cysts were diagnosed with computed tomography and ultrasonography and were treated after serologic confirmation.

Spinal intradural subpial lipomas are rare lesions. This case report emphasizes the role of MRI in diagnosing this lesion and in delineating its location. However, a dermoid cyst with a high lipid content of mixed triglycerides and unsaturated fatty acids without cholesterol may present the same appearance as an intradural lipoma and cannot be differentiated from it even with the use of short T1 inversion-recovery (STIR) images.

Schwannoma of the vestibule or the cochlea is an unusual lesion. In the past, most examples have been found at autopsy or as unsuspected findings at surgery for vertigo. The symptoms of isolated labyrinthine schwannoma may be indistinguishable from advanced Meniere's disease. Magnetic resonance imaging has led to pre-operative diagnosis in some cases. Two cases of schwannoma within the labyrinth from a series of 339 symptomatic acoustic tumours, are presented and the imaging findings are discussed.

Fluid collections are commonly seen following orthotopic liver transplantation. The majority of these collections are not infected and resolve spontaneously. However, infected collections are associated with significant morbidity and mortality and usually require drainage. Clinical signs of infection are frequently masked following transplantation due to immunosuppression. Intrahepatic collections usually represent abscesses or bilomas and invariably require intervention. Altered anatomical relationships result in signs that frequently help to differentiate these from loculated fluid within hepatic fissures. Other imaging features indicating infection include the presence of gas where none was seen previously, the development of a discrete wall and changes in the surrounding liver.

Fat-saturation (FS) pulse sequences can improve the detection of musculoskeletal lesions. We prospectively compared contrast-enhanced T1-weighted FS spin-echo (SE) images, T2-weighted FS fast spin-echo (FSE) images and inversion recovery (IR) FSE images to determine if any of these three pulse sequences is superior for depicting bone marrow and soft tissue lesions. T1-weighted FS-SE images (400-680/10-20 [TR/TE]) after intravenous injection of gadolinium-diethylenetriaminepentaacetic acid (DTPA), T2-weighted FS-FSE (2400-4200/96-112) and IR-FSE (3700-6000/12-14/170 [TR/TE/TI]) images were obtained with a 1.5-T magnet system in 35 patients. The visibility, margination and extent of 37 bone marrow and 67 soft tissue lesions, image uniformity, susceptibility and motion artefacts were qualitatively analysed by four radiologists. The number and size of lesions detected, the mean lesion signal-to-noise ration (S/N) and contrast-to-noise ratio (C/N) were also statistically compared. More bone and soft-tissue lesions were detected on the IR-FSE and T2-weighted FS-FSE than the T1-weighted FS-SE images. The IR-FSE images were significantly better than the T2-weighted FS-FSE and T1-weighted FS-SE images for bone marrow lesions conspicuity (P < 0.01). The soft-tissue lesions were also more conspicuous on the IR-FSE and T2-weighted FS-FSE images than on the T1-weighted FS-SE images (P < 0.005). The lesion extent and image quality were similar on all three sequences while motion artefacts were most severe on the IR-FSE and least severe on the T1-weighted FS-SE images (P < 0.001). Fat saturation was maximal on the IR-FSE images, resulting in a significantly higher mean C/N of bone marrow lesions. The mean C/N of soft-tissue lesions was higher on the T2-weighted FS-FSE images although the differences were not significant. The T2-weighted FS-FSE and IR-FSE sequences are superior to the contrast-enhanced T1-weighted FS-SE sequence for depicting musculoskeletal lesions. Bone marrow lesion conspicuity is greater on the IR-FSE images, with comparable scan time and image quality but more motion artifacts.

Although there are numerous communications between the portal and systemic venous systems, intrahepatic portosystemic venous shunts are not frequently encountered in clinical practice. Here we report a patient who presented with spastic paraparesis, who was found to have chronic liver disease with tubular intrahepatic portacaval shunting.