Parotid lymphomas - clinical and computed tomographic imaging features : otolaryngology

Objective. To review the clinical presentation and computed tomography (CT) imaging characteristics of all parotid lymphomas diagnosed at the study institution over a 7-year period. Design. Retrospective chart review of parotid lymphomas diagnosed between 1997 and 2004. Subjects. A total of 121 patients with parotid lesions were identified. After retrospective chart review; a total of 10 patients with histologically proven parotid lymphoma were included in the study; 8 of whom had CT scans available for assessment. Results. Ten patients with histologically proven lymphoma of the parotid gland were identified from among 121 patients with parotid neoplasms; an incidence in this series of 8.3. All lymphomas were of nonhodgkin's type. All patients presented with a painless unilateral parotid swelling. Most patients had a short history of less than 4 months' duration; of whom 3 presented with a rapidly evolving swelling of less then 1 month's duration. No patient had a background of SjA gren's disease or any other autoimmune disorders. The commonest finding noted on CT was of a unilateral; single mass of relative soft-tissue homogeneity with poorly defined; indistinct tumour margins. Associated loco-regional lymphadenopathy was identified in 2 cases; 1 clinically and another radiologically; multiple ipsilateral lesions were noted in 2 cases. No cases of contralateral disease were observed. Conclusion. Lymphoma has a clinical presentation similar to other neoplasms arising within the parotid gland. A unilateral; non-tender swelling was a universal finding. A history of less than 4 months may suggest the possibility of lymphoma. CT scanning is a useful adjunctive investigation to determine the site and extent of the disease; loco-regional nodal status and contralateral gland and neck status. Multifocality and associated adenopathy are associated with; but not exclusive to; parotid lymphoma. Although poor tumour boundary definition on CT imaging is a strong predictor of malignancy; no pathognomonic finding specific for lymphoma has been identified. The potential diagnosis of parotid lymphoma should be considered in all patients who present with a parotid mass

Sacral insufficiency fracture.

Insufficiency fractures of the sacrum are not uncommon and usually occur in osteoporotic bone with minimal or unremembered trauma. However, they appear to be relatively under-diagnosed and this pictorial review aims to highlight the condition, discuss the expected imaging features and some of the potential imaging pitfalls. Owing to its relationship with osteoporosis, the majority occur in elderly females and are frequently bilateral, often presenting as low back pain. Plain radiographs are generally normal and both clinician and radiologist need to consider the possibility of sacral insufficiency fracture to allow prompt accurate diagnosis and correct treatment. Lumbar spine MRI is among the first investigations performed and can enable the correct diagnosis to be made. Occasionally the MR appearances can mimic tumour or osteomyelitis. The "H" sign on an isotope bone scan is considered diagnostic in the right clinical setting, but this sign is often not present. CT is useful to confirm the diagnosis and exclude tumour or infection.

Multiphase contrast-enhanced helical CT of liver metastases from renal cell carcinoma.

The aim of this study was to evaluate whether in patients with metastatic renal cell carcinoma (RCC) multiphase liver studies would improve detection of metastatic liver disease. Forty-six consecutive patients with known metastatic RCC underwent standardized non-contrast and triphasic contrast enhanced hepatic CT examinations as part of their routine imaging studies. Once a liver abnormality was detected, it was characterized as metastatic by a panel of three radiologists who followed pre-set criteria. These criteria included change in size, biopsy results and lack of benign features. Presence and conspicuity of liver metastases were graded using a five-point scale by consensus of a panel of three radiologists. The highest number of lesions evaluated per patient was limited to ten. Seventy-two liver metastases were detected in 16 patients. Of these, 54 were seen on unenhanced scans; 47 in the hepatic arterial (HA) phase, at 25 s; 65 in the portal-venous (PV) phase, at 60 s; and 49 in delayed images, at 90 s. Scanning only during the PV phase would have missed seven lesions (10%), six of which were seen on unenhanced images and six were seen in HA phase. All patients with metastatic liver disease would have been identified by combination of unenhanced and PV phase or by HA and PV phase scanning. Forty-two lesions were graded more conspicuous on the PV phase, whereas 18 (25%) were more conspicuous on the HA phase. The combination of unenhanced, HA and PV scanning should be considered in the initial evaluation of patients with metastatic RCC for improved lesion detection and characterization. Subsequently, the combination of unenhanced and PV phase imaging is preferred.

Assessment of the airway in obstructive sleep apnea syndrome with 3-dimensional airway computed tomography.

OBJECTIVE: The goal was to evaluate 3-dimensional airway CT for upper airway assessment in obstructive sleep apnea syndrome (OSAS). DESIGN: Airway CT was obtained and 3-dimensional airway models were constructed prospectively for 40 patients with OSAS and 10 controls. Airway dimensions were correlated with polysomnography, and comparison was made between patients with and without OSAS. RESULTS: OSAS patients had a mean respiratory distress index of 51.9 events per hour. The mean minimum cross-sectional area (XSA) in the neutral position was 67.1 mm(2). Minimum XSA decreased in both the inspiratory and expiratory phases to 16.3 mm(2) and 15.0 mm(2), respectively (P<0.001). Complete airway obstruction occurred in 1 or more phases of respiration in 28 patients. Neither airway XSA nor length of obstruction correlated with sleep apnea parameters. No statistically significant differences in airway dimensions were found between OSAS and control patients. CONCLUSIONS: Airway CT demonstrates dynamic airway obstruction in OSAS but does not correlate well with clinically important disease parameters.

Liver metastases from melanoma: detection with multiphasic contrast-enhanced CT.

PURPOSE: To assess the clinical utility of multiphasic computed tomography (CT) of the liver in patients with metastatic melanoma. MATERIALS AND METHODS: Nonenhanced and biphasic hepatic CT examinations were performed in 28 patients with metastatic melanoma, and liver lesion conspicuity was graded. CT studies in 20 patients met the eligibility criteria, and 13 patients had liver lesions. RESULTS: A total of 57 liver lesions were seen on CT studies: 48 on hepatic arterial phase images, 49 on portal venous phase phase images, and 30 on delayed phase images. Of eight lesions overlooked on portal venous phase images, six were seen on nonenhanced images, and six were seen on arterial phase images. Twenty-eight lesions were graded as more conspicuous on portal venous phase images; 10 were graded as more conspicuous on arterial phase images. CONCLUSION: CT images obtained only during the portal venous phase would have resulted in eight (14%) overlooked lesions, which implies that more than one phase is needed for hepatic CT in patients with malignant melanoma. The combination of nonenhanced and portal venous phase CT was as effective as the combination of arterial and portal venous phase CT in these patients. Delayed phase CT did not improve lesion detection either alone or in combination with CT at other phases.

Intraoperative ultrasound of the biliary system: techniques and clinical applications.

Intraoperative ultrasonography (IOUS) of the intra- and extrabepatic biliary system is being used with increased frequency in many medical centers. The value of IOUS in facilitating surgery in patients with complicated diseases of the gallbladder or with stones in the bile ducts is well recognized. However, a variety of less common diseases affect the intrahepatic ducts, many of which require sophisticated surgical techniques when resection is being undertaken. In many situations, these operations can be facilitated by the use of IOUS, both for depicting segmental and ductal anatomy, and in guiding resections and anastomoses. This report summarizes the techniques currently used for performing IOUS of the biliary system, and illustrates the spectrum of clinical applications that may require IOUS guidance.

Nonopaque crystal deposition causing ureteric obstruction in patients with HIV undergoing indinavir therapy.

OBJECTIVE: We describe the unique CT features of ureteric calculi in six HIV-infected patients receiving indinavir, the most commonly used HIV protease inhibitor, which is associated with an increased incidence of urolithiasis. CONCLUSION: Ureteric obstruction caused by precipitated indinavir crystals may be difficult to diagnose with unenhanced CT. The calculi are not opaque, and secondary signs of obstruction may be absent or minimal and should be sought carefully. Images may need to be obtained using i.v. contrast material to enable diagnosis of ureteric stones or obstruction in patients with HIV infection who receive indinavir therapy.