S. H. Ng

Nasopharyngeal carcinoma: MRI and CT assessment

Abstract Precise assessment of the extent of nasopharyngeal carcinoma (NPC) represents the basic step towards optimal treatment. We compared the capacity of CT and MRI in assessing the extent of NPC in 67 patients. MRI was superior to CT in demonstrating lesions in the retropharyngeal node, skull base, intracranial area, carotid space, longus colli muscle and levator palatini muscle. Of 25 cases in which retropharyngeal adenopathy was recognised only on MRI, seven had been reported as showing oropharyngeal involvement and 18 as primary extension to the carotid space on CT. MRI showed skull-base involvement in 40 patients compared with 27 on CT and intracranial involvement in 38 patients versus 24 on CT. There was not a single case in which skull base invasion was seen on CT but not on MRI. MRI enabled improved recognition of tumour infiltration of longus colli muscles (34 cases compared with 15 on CT). It allowed us to clarify 12 questionable sinonasal opacities on CT. Overall, T-staging was changed in 18 of 67 patients (26.9 %), including upstaging in 15 cases and downstaging in 3 cases, after comparing CT with MRI. The nodel status was changed from negative on CT to positive on MRI in 4 of 67 patients (6 %). We believe that MRI allows more accurate evaluation of the extent of NPC than CT and should be the primary mode of investigation.

CT findings at lupus mesenteric vasculitis

Purpose: To describe the spectrum of early CT findings of lupus mesenteric vasculitis (LMV) and to assess the utility of CT in the management of this uncommon entity. Methods: Abdominal CT was performed within 1–4 days (average 2.2 days) of the onset of severe abdominal pain and tenderness in 15 women with systemic lupus erythematosus. Prompt high-dose i.v. corticosteroid was administered in 11 patients after the CT diagnosis of LMV was made. CT was performed after abdominal symptoms subsided. Results: Eleven cases revealed CT features suggestive of LMV including conspicuous prominence of mesenteric vessels with palisade pattern or comb-like appearance (CT comb sign) supplying focal or diffuse dilated bowel loops (n=11), ascites with slightly increased peritoneal enhancement (n=11), small bowel wall thickening (n=10) with double halo or target sign (n=8). Follow-up CT before high-dose steroid therapy revealed complete or marked resolution of the abnormal CT findings. Conclusion: CT is helpful for confirming the diagnosis of LMV, especially the comb sign which may be an early sign. Bowel ischemia due to LMV is less ominous than previously expected, and the abnormal CT findings were reversible when early diagnosis and prompt i.v. steroid therapy could be achieved.

Small bowel obstruction due to phytobezoar: CT diagnosis

Abstract. We report two cases of small bowel obstruction (SBO) due to phytobezoar impaction. In both cases, computed tomography (CT) demonstrated a well-defined, ovoid intraluminal mass with mottled gas pattern within the dilated small bowel at the site of obstruction and an abruptly collapsed lumen beyond the lesion. Recognition of these CT findings allows specific preoperative diagnosis of SBO owing to this uncommon lesion.

MRI in recurrent nasopharyngeal carcinoma

Abstract In this study, we retrospectively reviewed the MRI features of recurrent nasopharyngeal carcinoma (NPC) in 72 patients who underwent MRI before and after gadolinium injection. Recurrent NPC exhibited a high degree of regional spread and a variety of signal intensities and contours. MRI showed a nasopharyngeal mass in 50 patients (69.4 %); other sites of involvement included the parapharyngeal space (44.4 %), nasal cavity (12.5 %), paranasal sinuses (27.8 %), oropharynx (4.2 %), orbit (8.3 %), infratemporal fossa (18.1 %), skull base (59.8 %), intracranial area (51.4 %) and regional lymph nodes (15.3 %). On T2-weighted images, the nasopharyngeal mass gave high signal in 9 of 50 cases (18 %), intermediate in 27 (54 %), mixed in 8 (16 %) and low signal in 6 (12 %). Contrast enhancement was strong in 12 cases (24 %), moderate in 29 (58 %) and heterogeneous in 9 (18 %). The lesion was convex in 31 cases (62 %) and concave or straight in 19 (38 %). Recognition of the distribution and the appearance of recurrent NPC on MRI is essential for timely diagnosis and appropriate treatment.

Unusual liver MR findings of Wilson's disease in an asymptomatic 2-year-old girl.

We describe the unusual magnetic resonance (MR) findings of a case of Wilsons disease (WD) in an asymptomatic 2-year-old girl. Preenhanced computed tomography revealed multiple hyperdense areas in the liver. These lesions were hyperintense on T1-weighted and hypointense on T2-weighted MR images, results that might be ascribed to the paramagnetism of copper deposited in liver at a relatively early stage of the disease before severe liver cirrhosis had evolved.

Tuberculoma en plaque: CT

A 35-year-old woman presented with a 6-month history of intermittent headaches, vomiting and dizziness. CT showed a plaquelike mass with tiny calcifications along the surface of the left frontal lobe. The mass exhibited heterogeneous enhancement with a few lowdensity foci. Underlying sulcal obliteration and enhancement and white matter oedema were also noted. Histopathological examination of excised material was consistent with tuberculoma. Recognition of this unusual presentation of intracranial tuberculoma may facilitate appropriate diagnosis and management.

Retractile mesenteritis with colon and retroperitoneum involvement: CT findings

We report a case of retractile mesenteritis which involved the rectosigmoid colon and extended into the retroperitoneum with ureteral obstruction. These complications are rare. The radiological features [including computed tomography (CT)] are described.

Tuberous sclerosis with aortic aneurysm and rib changes: CT demonstration.

A 24-year-old man with tuberous sclerosis was found to have an aneurysm arising from the abdominal aorta and rib changes including sclerotic thickening, wavy periosteal new bone formation, and a cortical defect filled with soft tissue density.

Congenital extracranial meningioma

The authors report a case of congenital meningioma in a newborn. This tumour is extremely rare and only six cases have been reported in the literature. Those reported cases were mainly intracranial. This is the first case of a neonatal extracranial meningioma that was evaluated preoperatively by computed tomography and magnetic resonance imaging.

Infradiaphragmatic pulmonary sequestration combined with cystic adenomatoid malformation: unusual postnatal computed tomographic features

We present a surgically proven case of infradiaphragmatic pulmonary sequestration combined with cystic adenomatoid malformation. Prenatal magnetic resonance imaging revealed a well-defined hyperintense mass with a hypointense septum in the left infradiaphragmatic region. Postdelivery computed tomography (CT) and 3-month follow-up CT showed replacement of intralesional cystic areas by solid content. Such unusual postnatal CT changes, to our knowledge, have not been previously documented.