Cricoid ridge ossification mimicking ingested fish bone on plain radiography: prevalence in Singapore

<p><b>INTRODUCTION</b>Ossification of the cricoid ridge mimicking impacted upper aerodigestive tract fish bone has been described in several case reports. We performed this study to determine the prevalence of such ossification in an adult population from Singapore and to identify specific imaging features that may aid in differentiating patients with cricoid ridge ossification from those with an upper aerodigestive tract impacted fish bone.</p><p><b>METHODS</b>We retrospectively evaluated 442 lateral neck radiographs of patients aged 16 years and above that were taken at the adult emergency department at National University Hospital, Singapore, during the four-month period between 1 September 2014 and 31 December 2014.</p><p><b>RESULTS</b>Ossification of the cricoid ridge mimicking fish bone appeared in 3.2% of our adult patients and was more common among patients aged above 40 years (n = 11/227; 4.8%). The ossified cricoid ridge was usually located at the C6 level (n = 9) and had a mean length of 5.5 (range 2-9) mm.</p><p><b>CONCLUSION</b>Ossified cricoid ridges may be misinterpreted on lateral neck radiography as ingested fish bones. While ossification of the cricoid ridge mimicking fish bones is rare, awareness of such ossification would reduce unnecessary further investigations of the upper aerodigestive tract in patients suspected of having an impacted foreign body.</p>

Clinics in diagnostic imaging (187). Popliteal artery entrapment syndrome (PAES) Type II

A 26-year-old male patient was referred for exercise-induced claudication that had interfered with his military duties for the past two years. He was an occasional smoker with no other significant cardiovascular risk factors. Initial Doppler ultrasonography showed narrowing of the popliteal artery. Further evaluation with magnetic resonance angiography demonstrated a short segment occlusion of the popliteal artery secondary to an anomalous origin of the medial head of the gastrocnemius muscle from the lateral femoral condyle. Based on the clinical presentation and imaging findings, he was diagnosed with popliteal artery entrapment syndrome. In this article, we discussed the typical presenting signs and symptoms of popliteal artery entrapment syndrome, the different imaging modalities available to aid diagnosis, classification of the condition and the available treatment options.

Peritoneal lymphomatosis mimicking peritoneal carcinomatosis: important imaging clues for correct diagnosis

Peritoneal lymphomatosis, a rare presentation of lymphoma, can mimic peritoneal carcinomatosis. Computed tomography findings in both conditions include omental caking, as well as peritoneal enhancement, thickening and nodularity. We report three cases of peritoneal lymphomatosis and give an analysis of the salient imaging features that aided in the accurate diagnosis of the condition in each case. Two of the three cases demonstrated elevated serum cancer antigen 125 levels, a marker commonly associated with ovarian carcinoma. It is thus critical to distinguish peritoneal lymphomatosis from carcinomatosis, as the prognosis and management are dramatically different.

Atypical enhancement pattern of hepatocellular carcinoma with portal vein thrombosis on multiphasic CT

<p><b>INTRODUCTION</b>The 2005 American Association for Study of Liver Diseases (AASLD) diagnostic criteria allow non-invasive diagnosis of hepatocellular carcinoma (HCC) based on their enhancement pattern but we have observed a high incidence of atypical enhancement characteristics in HCC associated with portal vein thrombosis. This study seeks to examine the radiological features of this particular subgroup.</p><p><b>MATERIALS AND METHODS</b>Patients with HCC and portal vein thrombosis who underwent pre-treatment multiphasic CT imaging were drawn from a surgical database. The arterial, portal venous and delayed phase images were assessed qualitatively and quantitatively (with region of interest [ROI] analysis) for lesion hypervascularity and washout. The background enhancement of the left and right lobes of the liver was also quantifi ed by ROI analysis.</p><p><b>RESULTS</b>Twenty-fi ve lesions in 25 patients were selected for analysis. Qualitative analysis showed that 10/25 (40%) lesions demonstrated arterial hypervascularity while 16/25 (64%) lesions showed washout. Ten out of 25 (40%) lesions demonstrated both arterial hypervascularity and washout. Quantitative analysis showed that the average absolute lesion enhancement from precontrast to arterial phases was 49.1 (± 17.1) HU for hypervascular lesions compared to 23.8 (± 16.6) HU for non-hypervascular lesions (P <0.01). The mean absolute enhancement of the background liver parenchyma in the arterial phase was 13.79 (± 7.9) HU for hypervascular lesions compared to 36.6 (± 30.6) HU for non-hypervascular lesions (P = 0.03).</p><p><b>CONCLUSION</b>A large proportion of HCC with portal vein thrombosis lack characteristic arterial hypervascularity, which may be secondary to compensatory increased arterial supply to the background liver. This is a potential pitfall when applying imaging criteria for diagnosis of HCC.</p>