Clinical Radiology

2010-08-01

Radiology congresses in the UK

A.A. Nicholson — 2010-06-04

The Royal College of Radiologists and the British Institute of Radiology have strong historical links and are natural partners. Many members of the BIR are radiologists. Therefore, when the UK Radiological Congress started facing difficulties we hoped it could be replaced by a new, more vigorous congress, under the auspices of the BIR and the RCR, beginning in 2012. Two essential elements of the plan were that the RCR would have control of the scientific program and that the BIR would be responsible for logistics and organization. Unfortunately, in early 2010, it became obvious that the financial calculations presented to us were very uncertain indeed, and that the officers of the College could not recommend them to our council. Therefore, with the greatest regret, we decided that the partnership with the BIR had to be dissolved.

Imaging in gastrointestinal stromal tumours: current status and future directions

R. Kochhar, P. Manoharan, M. Leahy, M.B. Taylor — 2010-04-28

Gastrointestinal stromal tumours (GISTs) have distinct biological and treatment-related features posing challenges for imaging. In this review the importance of imaging in different stages of patient management is discussed, emphasizing the unique characteristics of GISTs. Potential pitfalls of using the standard response criteria on conventional imaging have been highlighted. These include size measurements, which may not adequately reflect response rates, pseudo-progression, and spurious new lesions. Furthermore, the role of positron emission tomography/computed tomography (PET/CT) in early response evaluation and in the detection of both primary and acquired resistance is explored. The current role and future directions of use of both conventional and metabolic imaging in the management of GISTs are discussed.

Classical and unusual imaging appearances of melorheostosis

S. Suresh, T. Muthukumar, A. Saifuddin — 2010-04-20

This comprehensive review will discuss the classical and unusual radiological features of melorheostosis, which is an uncommon, non-hereditary, benign, sclerosing mesodermal disease with an incidence of 0.9 cases per million. The presentation of melorheostosis in the appendicular skeleton (more commonly involved) and in the axial skeleton (very few documented case reports) will be discussed. The aim of the review is to illustrate the associations and rare, but recognized, complications of the disorder. The role of cross-sectional imaging in the form of magnetic resonance imaging (MRI) and computed tomography (CT) in revealing the spectrum of disease manifestation and differentiation from other disease entities and malignancy will be explored.

Coronary heart disease risk assessment and characterization of coronary artery disease using coronary CT angiography: comparison of asymptomatic and symptomatic groups

Y. Hwang, Y. Kim, I.-M. Chung, J. Ryu, H. Park — 2010-06-11

Aim: To evaluate the prevalence of coronary artery disease (CAD) in relation to risk of coronary heart disease (CHD) and assess plaque characteristics from coronary computed tomography (CT) angiography in asymptomatic and symptomatic patients.Materials and methods: Three hundred and ninety consecutive patients [asymptomatic group, n=138; symptomatic group (atypical or non-anginal chest pain), n=252] were retrospectively enrolled. They were subsequently classified into three CHD risk categories, based on the National Cholesterol Education Program guidelines, and 10 year risks of coronary events were calculated using Framingham risk score. CT was evaluated for stenosis, plaque composition, and coronary calcium scores.Results: CAD was observed in 42% of the asymptomatic group and 62% of the symptomatic group. In the former, the prevalence of CAD in low-, moderate- and high-risk subgroups was 21.4, 47.4 and 65%, respectively, and was 33.3, 74.4, and 72.4% in the symptomatic group. Framingham 10-year risks of coronary events were significantly higher in patients with CAD than in normal participants, and receiver operating characteristics curves showed that discriminatory power was poor in the asymptomatic group and symptomatic men, and good in symptomatic women. Of the participants in the asymptomatic group, 12% exhibited only non-calcified plaques and of the symptomatic group, 7% exhibited only non-calcified plaques. The coronary calcium score was significantly higher for significant stenosis than for non-significant stenosis in both groups.Conclusions: The prevalence of CAD was not negligible even in subgroups with low-to-moderate CHD risk. Additionally, the Framingham risk score was effective for predicting CAD only in symptomatic women. Coronary calcium scores correlated with significant stenosis; however, a sizeable percentage of both groups had only non-calcified plaques.

Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography

2010-05-03

Aim: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs.Materials and methods: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring ≤20mm and from 15 normal participants. Each dataset included standard and corresponding DES images. There were six non-solid, 10 part-solid, and 10 solid nodules. The mean size of the 26 nodules was 15±4.8mm. Receiver operating characteristic (ROC) analysis was performed to compare the performance of the eight board-certified radiologists.Results: For the eight radiologists, the mean value of the area under the ROC curve (AUC) without and with DES images was 0.62±0.05 and 0.68±0.05, respectively; the difference was statistically significant (p=0.02). For part-solid nodules, the difference of the mean AUC value was statistically significant (AUC=0.61±0.07 versus 0.69±0.05; p<0.01); for non-solid nodules it was not (AUC=0.62±0.1 versus 0.61±0.09; p=0.73), and for solid nodules it was not (AUC=0.75±0.1 versus 0.78±0.08; p=0.23). For nodules with overlapping bone shadows, the difference of the mean AUC value was statistically significant (p=0.03), for nodules without overlapping, it was not (p=0.26).Conclusion: Use of a double-exposure DES technique at FPD chest radiography significantly improved the diagnostic performance of radiologists to detect small pulmonary nodules.

Provisional reporting of polytrauma CT by on-call radiology registrars. Is it Safe?

R.H. Briggs, E. Rowbotham, A.L. Johnstone, A.G. Chalmers — 2010-06-10

Aim: To assess the accuracy of provisional reporting and the impact on patient management.Materials and methods: Over a 6 month period, 137 polytrauma computed tomography (CT) examinations were performed by on-call registrar radiologists at our institution. After exclusions, 130 cases were analysed. Discrepancies between registrar and consultant reports were reviewed and classified as either major or minor dependent on potential impact on patient safety. The relationship between seniority of reporting registrar and likelihood of a missed finding was analysed using the Chi-square test.Results: Of the 130 patients, 46 (35%) had a serious injury, 36 (28%) a minor injury, and 48 (38%) no identifiable injury on CT. There were 32 (25%) patients with discrepancies of which 24 (18%) had missed or significantly under-reported findings and eight (6%) overcalled findings. There were six misses classified as major; the remaining 18 were classified as minor. No association was found between the seniority of reporting registrar and the likelihood of a miss (p=0.96).Conclusion: The incidence of major discrepancies between the provisional and final report was low and did not lead to any significant clinical deterioration. Our study provides a reference of the commonly missed injuries. We conclude that registrar provisional reporting of polytrauma is safe; however, note that a large proportion of examinations are normal and that further work is required to produce robust criteria given the radiation risk to a young population group scanned in trauma.

Classification of non-aneurysmal subarachnoid haemorrhage: CT correlation to the clinical outcome

S. Nayak, A.B. Kunz, K. Kieslinger, G. Ladurner, M. Killer — 2010-06-21

Aim: To propose a new computed tomography (CT)-based classification system for non-aneurysmal subarachnoid haemorrhage (SAH), which predicts patients' discharge clinical outcome and helps to prioritize appropriate patient management.Methods and materials: A 5-year, retrospective, two-centre study was carried out involving 1486 patients presenting with SAH. One hundred and ninety patients with non-aneurysmal SAH were included in the study. Initial cranial CT findings at admission were correlated with the patients’ discharge outcomes measured using the Modified Rankin Scale (MRS). A CT-based classification system (type 1–4) was devised based on the topography of the initial haemorrhage pattern.Results: Seventy-five percent of the patients had type 1 haemorrhage and all these patients had a good clinical outcome with a discharge MRS of ≤1. Eight percent of the patients presented with type 2 haemorrhage, 62% of which were discharged with MRS of ≤1 and 12% of patients had MRS 3 or 4. Type 3 haemorrhage was found in 10%, of which 16% had good clinical outcome, but 53% had moderate to severe disability (MRS 3 and 4) and 5% were discharged with severe disability (MRS 5). Six percent of patients presented with type 4 haemorrhage of which 42% of the patients had moderate to severe disability (MRS 3 and 4), 42% had severe disability and one-sixth of the patients died. Highly significant differences were found between type 1(1a and 1b) and type 2 (p=0.003); type 2 and type 3 (p=0.002); type 3 and type 4 (p=0.001).Conclusion: Haemorrhages of the type 1 category are usually benign and do not warrant an extensive battery of clinical and radiological investigations. Type 2 haemorrhages have a varying prognosis and need to be investigated and managed along similar lines as that of an aneurysmal haemorrhage with emphasis towards radiological investigation. Type 3 and type 4 haemorrhages need to be extensively investigated to find an underlying cause.

Outcome of a retrieval stent filter and 30mm balloon dilator for patients with Budd–Chiari syndrome and chronic inferior vena cava thrombosis: a prospective pilot study

P.-X. Ding, X.-W. Han, G. Wu, Y.-D. Li, S.-F. Shui, Y.-L. Wang — 2010-06-14

Aim: To evaluate the mid-term safety and efficacy of a retrieval stent filter and 30mm balloon dilator in the treatment of Budd–Chiari syndrome (BCS) patients with chronic inferior vena cava (IVC) thrombosis.Materials and methods: Twenty-three consecutive patients with BCS and chronic IVC thrombosis were treated with a retrieval stent filter and a 30mm balloon dilator, and subsequently underwent color Doppler ultrasound follow-up at our hospital. Data relating to the technical success, angiographic and ultrasound results, mortality, morbidity, and final clinical outcome were collected retrospectively and follow-ups were performed 1, 3, 6, and 12 months after placement of the stent, and annually thereafter.Results: Stent filter placement and balloon dilation were technically successful in all patients, with no procedure-related complications. Removal of the stent filter was technically successful in 22 of 23 attempts, yielding a technical successful rate of 95.7% (95% confidence intervals (CI): 87%, 105%). Inferior vena cavagrams performed immediately before stent removal demonstrated that the IVC thrombus had completely resolved in all patients without pulmonary embolism. The mean primary patency rate 3, 6, 12, and 24 months after venoplasty was 0.91 (95% CI: 0.79–1.04), 0.87 (95% CI: 0.72–1.02), 0.87 (95% CI: 0.72–1.02), and 0.87 (95% CI: 0.72–1.02), respectively. The secondary patency rates were 1.00 throughout the follow-up period. All patients are alive with resolution of the symptoms at the time of this report.Conclusions: The preliminary results indicate that the retrieval stent filter and 30mm balloon dilator are a safe and effective treatment for BCS patients with chronic IVC thrombosis.

Nephrogenic systemic fibrosis: UK survey of the use of gadolinium-based contrast media

O. Rees, S.K. Agarwal — 2010-06-14

Aim: To identify the current practice of administration of gadolinium-based contrast media (Gd-CM) within the UK with respect to the European Society of Urogenital Radiology (ESUR) guidelines on nephrogenic systemic fibrosis (NSF).Materials and methods: One hundred and fifty-two institutions were contacted to request details regarding the use of Gd-CM at their institution, their awareness of NSF, and of the ESUR guidelines, and their departmental policy on the administration of Gd-CM agents associated with NSF (high-risk agents) in patients with diminished renal function.Results: Of the 100 institutions that replied, 72% used a cyclic agent as a first-line Gd-CM. The majority of institutions used more than one Gd-CM, and 57% used a high-risk Gd-CM. Seventy percent were aware of the ESUR guidelines, and of the 57% that used a high-risk Gd-CM, 9% did not check renal function at all prior to administration. The course of action of the remaining 48% was varied in patients with diminished renal function with some changing to a low-risk Gd-CM and others electing not to use Gd-CM at all. Five percent continued to use a high-risk Gd-CM with an estimated glomerular filtration rate <30ml/min.Conclusion: The present survey shows that the majority of institutions use a low-risk Gd-CM as a first-line agent; however, a number of institutions do use a high-risk Gd-CM and their course of action for patients with diminished renal function is varied. Given current evidence, it is advisable to use a low-risk Gd-CM, such as a cyclic agent, in patients with diminished renal function.

Pulmonary sarcoidosis: the ‘Great Pretender’

K.E. Hawtin, M.E. Roddie, F.A. Mauri, S.J. Copley — 2010-05-13

Sarcoidosis has a wide spectrum of appearances within the thorax. This review will discuss and illustrate the range of pulmonary manifestations on high-resolution computed tomography and chest radiography, concentrating on atypical features and examples of sarcoidosis mimicking other lung diseases. All included cases have been histologically confirmed. Such variable imaging appearances should alert the radiologist to consider sarcoidosis as a differential diagnosis in the context of interstitial lung disease.

Pitfalls and artefacts in performance and interpretation of contrast-enhanced MR angiography of the lower limbs

P.N. Malcolm, P. Craven, D. Klass — 2010-05-13

Peripheral contrast-enhanced MR angiography is widely used for anatomical imaging of the arterial system of the lower limb. There are several pitfalls in the planning, acquisition, and interpretation of these studies that can result in the loss of important diagnostic information, as well as artefacts that can be misinterpreted as disease entities. This review illustrates the range of these potential sources of error and how to avoid them.

FDG PET/CT imaging in granulomatous changes secondary to breast silicone injection

L. Ho, H. Wassef, J. Seto — 2010-04-30

Silicone-related granulomatous changes at positron-emission tomography (PET) are not very well documented in the literature. In this report, we discuss a case of biopsy-proven granuloma secondary to breast silicone injection and its characteristics on PET and computed tomography (CT) and several aspects of its other imaging characteristics, management, and prognosis.

Idiopathic bilateral ureteric entrapment within the sacroiliac joints causing bilateral hydroureteronephrosis

J.T.H. Yeung, J.K.F. Ma, A.W.T. Yung, R.L.F. Cheng — 2010-05-12

Bilateral ureteric entrapment is known in conditions such as retroperitoneal fibrosis, post-aortic aneurysm repair, retroperitoneal lymphadenopathy, and tumour. Unilateral ureteric entrapment has been reported in cases of hernia and in cases of young patients with pelvic trauma. However, ureteric entrapment within the sacroiliac joints is a very rare condition. We present a case of bilateral ureteric entrapment within the sacroiliac joints in an elderly lady with no known history of trauma. To the authors’ knowledge, this has not been previously reported in the scientific literature.

The war on terror and radiological error?

A.P. Toms — 2010-04-28

The concept of radiological error is unfortunately a familiar one, but it can be difficult to define exactly what it is that constitutes an error. There are errors of detection that occur because we miss things, and there are errors of interpretation that occur because we see things but ignore them or get the diagnosis wrong. This classification has the merit of simplicity but it is not quite true. It appears that our eyes and parts of our brain can see things that never quite make it into conscious thought. Eye-tracking studies have demonstrated that radiologists will fix on nodules on a chest radiograph for longer than 200ms, a clear sign that a lesion has been registered by the brain, without any conscious recognition of the abnormality. Spots and misses seem to blur into one.

Re: The radiological diagnosis and treatment of renal angiomyolipoma—Current status

Satheesh Ramamurthy, Christopher Chick — 2010-05-04

We would like to congratulate Dr Halpenny et al. for the excellent review of the radiological diagnosis and treatment of renal angiomyolipoma. In their article they mentioned the technical difficulties of selective embolization of the angiomyolipoma with alcohol. We have found that using a 1:1 mixture of alcohol with a viscous oily contrast medium, such as lipiodol, and embolization under careful screening greatly reduces this risk. We also embolize using very small amounts (0.5ml aliquots) of the mixture followed by a saline flush via a three-way tap using 1ml syringes. Obtaining a stable superselective position with a microcatheter prior to embolization is vital to minimize non-target embolization. We have not found the need to use occlusion balloons. Chick et al. detailed the findings in 34 patients treated using this method. We have found that in majority of the cases, the volume of alcohol required is very small and the process is quick and safe.

Re: CT “invisible” lesion of the major salivary glands — a diagnostic pitfall of contrast enhanced CT. A reply

P.L. Kei, T.Y. Tan — 2010-04-28

Sir—We thank Drs Burke and Howlett for their valuable comments. We acknowledge the distinct advantages of ultrasound over other imaging methods, namely the fact that it uses no ionizing radiation, is inexpensive, and may help in guiding biopsy. The drawbacks are that it is operator-dependent and assessment of deep structures is suboptimal. A fact that we omitted in our original correspondence is that ultrasound imaging studies typically do not provide the global perspective of the lesion that computed tomography (CT) provides with respect to normal head and neck structures, such as the mandible and nose bridge, which our referring physicians request.

Re: CT ‘‘invisible'’ lesion of the major salivary glands — diagnostic pitfall of contrast-enhanced CT

N.K.K. Venkatanarasimha, P.M. Hughes — 2010-04-28

Sir—We read with great interest the recent correspondence and reply regarding the computed tomography (CT) “invisible” lesion of the major salivary glands. We strongly agree with comments of Thomas et al. with regards to the drawbacks of CT in the evaluation of major salivary glands. We would like to further highlight certain key-points related to the CT drawbacks and advantages of high-resolution ultrasonography, which make it the workhorse of major salivary gland imaging.

Re: Posterior parahepatic cyst as an incidental finding—review of 40 cases

M.P. Williams, D. Shetty, B.M. Fox — 2010-04-28

Sir—As noted by Harvin and Adduci isolated nodular structures are not infrequently observed adjacent to the posterior segment of the right lobe of the liver. In their paper they characterized 40 out of a total of 150 examples they had identified as parahepatic cysts.

Re: Posterior parahepatic cyst as an incidental finding—review of 40 cases. A reply

H.J. Harvin, A.J. Adduci — 2010-05-24

Sir—We would like to thank Drs Williams, Shetty, and Fox for their contribution to the discussion on posterior parahepatic nodules and incidental retroperitoneal cysts. They provide the entity of accessory liver as an additional consideration to be included in the differential diagnosis for posterior parahepatic nodules. Accessory liver was also our first hypothesis for the parahepatic lesions that we had observed. However, in our early experience, our suspicion for accessory hepatic tissue was not confirmed by magnetic resonance imaging (MRI) with Feridex (ferumoxide injectable solution, Bayer HealthCare) in one patient and technetium 99m sulphur colloid with single photon-emission computed tomography (SPECT) in another patient, with both examinations failing to show functioning hepatic tissue. We subsequently moved further away from accessory liver as an explanation for these lesions based on multiple MRI examinations in additional patients showing non-enhancing cysts. We have repeatedly observed that it is not appropriate to infer accessory hepatic tissue on the basis of proximity to the liver or similarity of attenuation measurements, and we no longer routinely mention the possibility of accessory or ectopic liver in reports for cases with incidental posterior parahepatic lesions similar to those described in our report.

Corrigendum to: The diagnostic value of the sagittal multiplanar reconstruction CT images for nasal bone fractures [65(4): 308–314]

B.H. Kim, H.S. Seo, A.-Y. Kim, Y.S. Lee, Y.H. Lee, S.-I. Suh, D.H. Lee — 2010-05-17

a in the above article was incorrect. The correct figure is therefore shown below.

Notices