Introduction:Although pulmonary hydatid cysts can be diagnosed on computed tomography (CT), sometimes findings can be atypical. Other hypodense infective or neoplastic lesions may mimic hydatid cysts. We proposed that magnetic resonance imaging (MRI) may act as a problem-solving tool, aiding the definite diagnosis of hydatid cysts and differentiating it from its mimics. The aim of this study is to assess the findings of pulmonary hydatid cysts on CT and MRI and the additional contribution of MRI in doubtful cases.Materials and Methods:This is a retrospective study of 90 patients with suspected hydatid cysts. CT and MRI findings were noted and role of MRI in diagnosing hydatid cysts and its mimics was studied. Descriptive statistics for CT findings and sensitivity and specificity of MRI were calculated using surgery or histopathology as gold standard.Results:Of the 90 patients with suspected pulmonary hydatid cysts, there were 52 true-positive and 7 false-positive cases on CT. Commonest CT finding was unilocular thick-walled cyst. In the 26 patients who had additional MRI, based on T2-weighted hypointense rim or folded membranes, accurate preoperative differentiation of 14 patients with hydatid cysts from 10 patients with alternate diagnosis was possible. There was one false-positive and one false-negative case on MRI.Conclusion:Although hydatid cyst can be diagnosed on CT on most occasions, sometimes there are challenges with certain mimics and atypical appearances. T2-weighted MRI can act as a problem solving tool to conclusively diagnose hydatid cyst or suggest an alternate diagnosis.

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Among pyogenic liver abscesses, melioid etiology is considered in endemic regions in the presence of known health or occupational risk factors. "Honeycomb sign," used to describe an abscess with multiple internal septations dividing the abscess cavity into multiple loculations of comparable sizes on imaging, is a sensitive sign for melioid liver abscess. This is a retrospective case-control study investigating incidence, sensitivity, and specificity of "honeycomb sign" in melioid liver abscess, in a cohort of patients with culture-proven melioidosis infection. Abscesses ≥ 2 cm were analyzed for the honeycomb sign. value< 0.05 was taken as statistically significant. Interobserver agreement was calculated between two radiologists for the presence of the sign, sensitivity, and specificity. A total of 40 abscesses were analyzed. Thirty-four abscesses (85%) manifested the honeycomb sign with interobserver agreement (kappa = 0.70 and 0.92). Sensitivity of the sign is 85% (95% confidence interval [CI]: 70-94%), specificity is 75% (95% CI: 59-87%), positive predictive value is 77% (95% CI: 62-88%), and negative predictive value is 83% (95% CI: 67-94%). If abscess size is ≥ 3 cm, the sensitivity is 91% (95% CI: 77-98%), specificity is 75% (95% CI: 59-87%), positive predictive value is 76% (95% CI: 61-88%), and negative predictive value is 91% (95% CI: 76-98%). Honeycomb sign is a novel imaging marker for melioid liver abscess. Increased awareness and recognition of this imaging feature has the potential to affect patient management.

Background:Tetralogy of Fallot (TOF) is a complex congenital heart disease with anatomic variations. Although the pulmonary valve in TOF is abnormal, it has not been studied well, especially on newer imaging modalities such as multidetector computed tomography (CT), which gives excellent anatomic detail.Aims:The aim of this study was to assess the morphology of pulmonary valve in TOF on CT and evaluate its association with the degree of hypoplasia of infundibulum and pulmonary trunk.Materials and Methods:The cardiac CT scans of 30 patients with TOF were reviewed to evaluate the morphology of the pulmonary valve, infundibulum, and pulmonary arteries. Fisher's exact test was performed to examine the association between pulmonary valve morphology and degree of hypoplasia of the infundibulum and pulmonary trunk.Results:16.7% of patients with TOF had pulmonary atresia. The prevalence of tricuspid, bicuspid, and absent valves were 10%, 53.3% and 6.7%, respectively. In another 13.3% of patients, although valve tissue was present, exact morphology could not be determined on CT. The commissures of 62.5% of the bicuspid valves were at 12 o’clock and 6 o’clock or slightly off the midline. There was statistically significant association between valve morphology and degree of infundibular hypoplasia (P < 0.001) and calibre of pulmonary trunk (P < 0.001).Conclusion:Morphological abnormality of the pulmonary valve is common in TOF. The most common type of pulmonary valve in TOF patients is bicuspid valve with commissures at 12 o’clock and 6 o’clock or slightly off the midline. Fewer cusps of the pulmonary valve are associated with a more severe degree of pulmonary artery hypoplasia.

Objective Melioidosis being an important cause of community-acquired sepsis, caused by Burkholderia pseudomallei in the tropical and subtropical countries, is often underreported or misinterpreted on imaging investigations. We aim to describe the spectrum of imaging manifestations of melioidosis and to evaluate its role in prognosticating clinical outcome, and look for association of specific organ involvement with risk factors. Methods From January 2011 to October 2017, retrospective analysis of imaging investigations of 189 consecutive patients with culture-proven melioidosis was performed. Clinical and demographic records were collected from the hospital medical records. Results Out of 67% with a localised disease musculoskeletal involvement was most common, whereas the common organs involved in disseminated infections were the lungs, spleen, liver and genitourinary tract in descending order. Twenty percent suffered unfavourable outcome with a mortality rate of 8.5%. The lung involvement was associated with unfavourable outcome (OR 3.2 [95%CI 1.54–6.63] p = 0.002). The lymph node involvement (OR 0.22 [95% CI 0.05–0.95] p = 0.04) predicted a favourable outcome. Those with diabetes were at a higher risk of splenic (OR 3.05 [95% CI 1.62–5.77]; p = 0.001) and musculoskeletal involvement (OR 2.14 [95% CI 1.09–4.17] p = 0.03) of melioidosis. Conclusions In this study, we have described the spectrum of imaging manifestation of melioidosis and evaluated its association with clinical outcome. Respiratory system involvement in melioidosis showed significant association with unfavourable outcome. Diabetes mellitus, a common risk factor for melioidosis, is more prone for infection of the spleen and musculoskeletal system. Thus awareness of imaging manifestations of melioidosis can complement microbiological diagnostic tests for accurate early diagnosis and management.