Giant adrenal pseudocyst: A rare diagnosis

We present a rare case of giant adrenal pseudocyst as a cause of right upper quadrant (RUQ) pain and highlight the typical multimodality imaging features. The case demonstrates the imaging features associated with giant adrenal pseudocysts to aid accurate and timely diagnosis. Despite the rarity of these lesions they are important to consider as benign lesions can closely mimic malignant ones. Unenhanced and contrast‐enhanced CT is the imaging of choice for adrenal cysts. However, MRI can provide more exquisite assessment of cystic, solid and enhancing components. Pseudocysts can be purely cystic, mixed or solid. Classically, adrenal pseudocysts are described as cystic lesions (of homogenous water density) with a fibrous wall and thin internal septations. Mural/septal calcification is commonly demonstrated due to haemorrhage, this is discernible from central/amorphous calcification seen in malignant disease. As in this case, pseudocysts can contain solid components or layering secondary to haemorrhage. The key to differentiating organised haematoma from tumour is the lack of enhancement. If serial imaging is undertaken in these patients rapid changes in the solid components may be seen reflecting resolving haematoma. Adrenal pseudocysts are rare and have a wide differential. Cystic adrenal lesions warrant multimodality assessment as their imaging features aid diagnosis and differentiation from malignant disease. We suggest that MRI plays a complimentary role to CT. CT is superior at demonstrating mural/septal calcification but MRI aids in determining cystic components and differentiating haemorrhage from tumour.     

Diagnostic accuracy of 16‐slice CT coronary angiography in the evaluation of coronary artery disease

Multislice CT coronary angiography (CT‐CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16‐slice CT in the diagnosis of significant coronary stenosis (≥50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16‐slice CT‐CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT‐CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT‐CA findings assessed FCA by visual estimation. Of 1161 coronary segments assessable on FCA, 1103 segments (95%) were assessable on CT‐CA. The CT‐CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT‐CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient‐based analysis, CT‐CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT‐CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16‐slice CT‐CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT‐CA would appear to be a useful ‘rule‐out’ test for patients with low‐risk profile for ischaemic heart disease.     

Coronary artery anomalies in adults: Imaging at dual source CT coronary angiography

Congenital abnormalities of the coronary arteries have an incidence of 1%, and most of these are benign. However, a small number are associated with myocardial ischaemia and sudden death. Various imaging modalities are available for coronary artery assessment. Recently, multi‐detector CT has emerged as an accurate diagnostic tool for defining coronary artery anomalies. The purpose of this pictorial essay is to review the dual source CT appearance of congenital anomalies of the coronary arteries in adults.     

Haemobilia – a rare presentation of intrabiliary hydatid disease

Intrabiliary hydatid cysts have been known to cause complications. We report a rare case of calcified crumpled intrabiliary hydatid cyst causing massive haemobilia due to a hepatic artery pseudoaneurysm, an unusual complication of intrabiliary hydatid cyst. The patient was successfully treated by stenting of the pseudoaneurysm with overlapping stents.     

Prevalence of significant extracoronary findings on multislice CT coronary angiography examinations and coronary artery calcium scoring examinations

The purpose of the study was to review the prevalence of significant extracoronary findings in patients who underwent multislice CT coronary angiography examinations and coronary artery calcium scoring examinations. We reviewed the reports of 295 consecutive patients who underwent multislice CT coronary angiography examinations and 140 consecutive patients who had separate coronary calcium scoring examinations from September 2004 to March 2006 in our department's radiology information system. Additional investigations carried out as a result of these findings were also recorded. Fifty-six (19%) out of 295 patients had significant extracoronary findings on coronary CT angiography requiring clinical or radiological follow up. There were 60 significant extracoronary findings. These included 24 patients who had pulmonary abnormalities, 4 who had mediastinal abnormalities, 20 who had upper abdominal abnormalities and 5 who had non-coronary cardiac abnormalities. Three patients had both pulmonary and upper abdominal abnormalities. Eleven (8%) out of 140 patients had significant pulmonary, breast, mediastinal, upper abdominal and cardiac abnormalities on coronary artery calcium scoring examinations, yielding a total of 12 significant findings. In our experience, 19% of the patients who underwent multislice CT coronary angiography and 8% of the patients who underwent coronary artery calcium scoring examinations had significant extracoronary findings requiring follow up. It is therefore imperative for the reporting physician to review the entire examination after the coronary arteries have been assessed. The prevalence of extracoronary findings on these examinations may be of significance, resulting in additional 'hidden costs' if widespread 'screening' is adopted.     

A systematic review of radiation dose associated with different generations of multidetector CT coronary angiography

The purpose of this paper is to perform a systematic review on radiation dose reduction in coronary computed tomography (CT) angiography that is done using different generations of multidetector CT (MDCT) scanners ranging from four-slice to 320-slice CTs, and have different dose-saving techniques. The method followed was to search for references on coronary CT angiography (CTA) that had been published in English between 1998 and February 2011. The effective radiation dose reported in each study based on different generations of MDCT scanners was analysed and compared between the types of scanners, gender, exposure factors and scanning protocols. Sixty-six studies were eligible for inclusion in this analysis. The mean effective dose (ED) for MDCT angiography with retrospective electrocardiogram (ECG) gating without use of any dose-saving protocol was 6.0 ± 2.8, 10.4 ± 4.90 and 11.8 ± 5.9 mSv for four-slice, 16-slice and 64-slice CTs, respectively. More dose-saving strategies were applied in recent CT generations including prospective ECG-gating protocols, application of lower tube voltage and tube current modulation to achieve a noteworthy dose reduction. Prospective ECG-gating protocol was increasingly used in 64, 125, 256 and 320 slices with corresponding ED of 4.1 ± 1.7, 3.6 ± 0.4, 3.0 ± 1.9 and 7.6 ± 1.6 mSv, respectively. Lower tube voltage and tube current modulation were widely applied in 64-slice CT and resulted in significant dose reduction (P < 0.05). This analysis has shown that dose-saving strategies can substantially reduce the radiation dose in CT coronary angiography. The fact that more and more clinicians are opting for dose-saving strategies in CT coronary angiography indicates an increased awareness of risks associated with high radiation doses among them.     

Systemic‐pulmonary artery shunt: A rare cause of false‐positive filling defect in the pulmonary arteries

Computed tomographic (CT) pulmonary angiography is widely used for evaluation of pulmonary embolism. Intraluminal filling defects in the contrast enhanced pulmonary arteries are considered diagnostic of pulmonary emboli. We report a false‐positive case where filling defects in the pulmonary artery were due to mixing of blood from a complex shunt or vascular malformation between the systemic arteries and pulmonary artery.     

Radiation dose and diagnostic image quality associated with iterative reconstruction in coronary CT angiography: A systematic review

The aim of this systematic review is to evaluate the radiation dose reduction achieved using iterative reconstruction (IR) compared to filtered back projection (FBP) in coronary CT angiography (CCTA) and assess the impact on diagnostic image quality. A systematic search of seven electronic databases was performed to identify all studies using a developed keywords strategy. A total of 14 studies met the criteria and were included in a review analysis. The results showed that there was a significant reduction in radiation dose when using IR compared to FBP (P < 0.05). The mean and standard deviation (SD) difference of CTDI_vol and dose‐length‐product (DLP) were 14.70 ± 6.87 mGy and 186 ± 120 mGy.cm respectively. The mean ± SD difference of effective dose (E_D) was 2.9 ± 1.7 mSv with the range from 1.0 to 5.0 mSv. The assessment of diagnostic image quality showed no significant difference (P > 0.05). The mean ± SD difference of image noise, signal‐noise ratio (SNR) and contrast‐noise ratio (CNR) were 1.05 ± 1.29 HU, 0.88 ± 0.56 and 0.63 ± 1.83 respectively. The mean ± SD percentages of overall image quality scores were 71.79 ± 12.29% (FBP) and 67.31 ± 22.96% (IR). The mean ± SD percentages of coronary segment analysis were 95.43 ± 2.57% (FBP) and 97.19 ± 2.62% (IR). In conclusion, this review analysis shows that CCTA with the use of IR leads to a significant reduction in radiation dose as compared to the use of FBP. Diagnostic image quality of IR at reduced dose (30–41%) is comparable to FBP at standard dose in the diagnosis of CAD.     

Unilateral renal phaeohyphomycosis due to Bipolaris spicifera in an immunocompetent child – rare case presentation and review of literature

Phaeohyphomycosis refers to infections caused by phaeoid fungi that can have an aggressive course in normal hosts. We report a case of left‐sided renal phaeohyphomycosis due to Bipolaris spicifera in a 7‐year‐old immunocompetent male child. He presented with fever, dysuria, nausea, vomiting and flank pain. Examination revealed tenderness at the left costovertebral angle. Histological examination and culture of biopsy from left kidney and blood yielded the fungal pathogen Bipolaris spicifera. His past history revealed that he was diagnosed perinatally with bilateral hydronephrosis due to bilateral pelvic ureteric junction obstruction. He underwent an open dismembered pyeloplasty on the left side followed by the right side pyeloplasty at the age of 6 months and 1.5 years respectively. He was on a regular follow‐up for 5 years and had been doing well. Now he was diagnosed as a case of unilateral renal phaeohyphomycosis. The patient was managed successfully with antifungal drugs amphotericin B and itraconazole. A review of previously reported bipolaris cases with their clinical manifestations, treatment and outcome is presented. Renal phaeohyphomycosis remains an unusual disease. Aggressive diagnostic approaches and careful management helped in survival of the patient.     

Inter-observer variation in delineation of the heart and left anterior descending coronary artery in radiotherapy for breast cancer: A multi-centre study from Denmark and the UK

Background and purpose

To determine the extent of inter-observer variation in delineation of the heart and left anterior descending coronary artery (LADCA) and its impact on estimated doses.

Methods and materials

Nine observers from five centres delineated the heart and LADCA on fifteen patients receiving left breast radiotherapy. The delineations were carried out twice, first without guidelines and then with a set of common guidelines.

Results

For the heart, most spatial variation in delineation was near the base of the heart whereas for the LADCA most variation was in its length at the apex of the heart. Common guidelines reduced the spatial variation for the heart and the length of the LAD, but increased the variation in the anterior–posterior/right–left plane. The coefficients of variation (CV) in the estimated doses to the heart were: mean dose 7.5% without and 3.6% with guidelines, maximum dose 8.7% without and 4.0% with guidelines. The CVs in the estimated doses to the LADCA were: mean dose 27% without and 29% with guidelines, maximum dose 39% without and 31% with guidelines.

Conclusions

For the heart, there was little inter-observer variation in the estimated dose, especially when guidelines were used. In contrast, for the LADCA there was substantial variation in the estimated dose, which was not reduced with guidelines.