The comparative accuracy of ultrasound and mammography in the detection of breast cancer.

AIM: This study was performed to determine the accuracy of ultrasound (USG) as compared to mammography (MMG) in detecting breast cancer. METHODS: This was a review of patients who had breast imaging and biopsy during an 18-month period. Details of patients who underwent breast biopsy were obtained from the department biopsy record books and imaging request forms. Details of breast imaging findings and histology of lesions biopsied were obtained from the hospital Integrated Radiology Information System (IRIS). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of USG and MMG were calculated with histology as the gold standard. RESULTS: A total of 326 breast lesions were biopsied. Histology results revealed the presence of 74 breast cancers and 252 benign lesions. USG had a sensitivity of 82%, specificity of 84%, PPV = 60%, NPV = 94% and an accuracy of 84%. MMG had a sensitivity of 49%, specificity of 89%, PPV = 53%, NPV = 88% and an accuracy of 81%. A total of 161 lesions which were imaged with both modalities were analyzed to determine the significance in the differences in sensitivity and specificity between USG and MMG. Sensitivity of USG (75%) was significantly higher than sensitivity of MMG (44%) (X(2)1=6.905, p=0.014). Specificity of MMG (91%) was significantly higher than specificity of USG (79%) (X(2)1=27.114, p<0.001). Compared with MMG, the sensitivity of USG was 50% (95% CI 10%-90%) higher in women aged less than 50 years (X(2)1=0.000, p=1.000) and 27% (95% CI 19%-36%) higher in women aged 50 years and above (X(2)1=5.866, p=0.015). Compared with MMG, the sensitivity of USG was 40% (95% CI 10%-70%) higher in women with dense breasts (X(2)1=0.234, p=0.628) and 27% (95% CI 9%-46%) higher in women with non-dense breasts (X(2)1=4.585, p=0.032). CONCLUSION: Accuracy of USG was higher compared with MMG. USG was more sensitive than MMG regardless of age group. However, MMG was more specific in those aged 50 years and older. USG was more sensitive and MMG was more specific regardless of breast density. In this study, 20% of breast cancers detected were occult on MMG and seen only on USG.

CLICK--topology-independent comparison of biomolecular 3D structures.

Our server, CLICK: http://mspc.bii.a-star.edu.sg/click, is capable of superimposing the 3D structures of any pair of biomolecules (proteins, DNA, RNA, etc.). The server makes use of the Cartesian coordinates of the molecules with the option of using other structural features such as secondary structure, solvent accessible surface area and residue depth to guide the alignment. CLICK first looks for cliques of points (3-7 residues) that are structurally similar in the pair of structures to be aligned. Using these local similarities, a one-to-one equivalence is charted between the residues of the two structures. A least square fit then superimposes the two structures. Our method is especially powerful in establishing protein relationships by detecting similarities in structural subdomains, domains and topological variants. CLICK has been extensively benchmarked and compared with other popular methods for protein and RNA structural alignments. In most cases, CLICK alignments were statistically significantly better in terms of structure overlap. The method also recognizes conformational changes that may have occurred in structural domains or subdomains in one structure with respect to the other. For this purpose, the server produces complementary alignments to maximize the extent of detectable similarity. Various examples showcase the utility of our web server.

Hypertension in a residential home for the elderly in Penang, Malaysia.

A study of residents at the Silver Jubilee Home for the Aged was conducted to determine the prevalence, awareness and control of hypertension in this elderly community in Penang, Malaysia. Prevalence of hypertension was 36%, with 81% of patients being initially aware of this diagnosis. This relatively low hypertension prevalence rate may be because residents have a fairly sheltered lifestyle with less social stress and a daily routine that incorporates adequate exercise. Similarly, the high hypertension awareness rate compared to reported figures in the community may be because residents are more regularly monitored by the attending medical care-givers. At the beginning of the study, only 34% of hypertensive patients were well controlled with a blood pressure less than 140/90 mm Hg. This proportion rose to 53% at the end of study period. Compliance is better at a residential home because medication is served by their care-givers and cost is absorbed in this charitable organization. Our study suggests that hypertension awareness and control can be reasonable for the elderly in a residential home.

EZH2 promotes neoplastic transformation through VAV interaction-dependent extranuclear mechanisms.

Recently, we reported that the histone methyltransferase, EZH2, controls leukocyte migration through interaction with the cytoskeleton remodeling effector, VAV, and direct methylation of the cytoskeletal regulatory protein, Talin. However, it is unclear whether this extranuclear, epigenetic-independent function of EZH2 has a profound impact on the initiation of cellular transformation and metastasis. Here, we show that EZH2 increases Talin1 methylation and cleavage, thereby enhancing adhesion turnover and promoting accelerated tumorigenesis. This transforming capacity is abolished by targeted disruption of EZH2 interaction with VAV. Furthermore, our studies demonstrate that EZH2 in the cytoplasm is closely associated with cancer stem cell properties, and that overexpression of EZH2, a mutant EZH2 lacking its nuclear localization signal (EZH2ΔNLS), or a methyl-mimicking Talin1 mutant substantially promotes JAK2-dependent STAT3 activation and cellular transformation. Taken together, our results suggest a critical role for the VAV interaction-dependent, extranuclear action of EZH2 in neoplastic transformation.

Dynamic change in natural killer cell type in the human ocular mucosa in situ as means of immune evasion by adenovirus infection.

The most severe form of virus-induced inflammation at the ocular surface is epidemic keratoconjunctivitis (EKC), often caused by group D human adenoviruses (HAdVs). We investigated the dynamics and mechanisms of changes in natural killer (NK) cell types in the human ocular mucosal surface in situ over the course of infection. In the acute phase of infection, the mature CD56(dim)NK cells that comprise a major subpopulation in the normal human conjunctiva are replaced by CD56(bright)NK cells recruited to the ocular surface by chemokines produced by the infected epithelium, and NKG2A-expressing CD56(dim) and CD56(bright) NK cells become the major subpopulations in severe inflammation. These NK cells attracted to the mucosal surface are however incapable of mounting a strong antiviral response because of upregulation of the inhibitory ligand human leukocyte antigen-E (HLA-E) on infected epithelium. Furthermore, group D HAdVs downregulate ligands for activating NK cell receptors, thus rendering even the mature NKG2A(-)NK cells unresponsive, an immune-escape mechanism distinct from other adenoviruses. Our findings imply that the EKC-causing group D HAdVs utilize these multiple pathways to inhibit antiviral NK cell responses in the initial stages of the infection.

A comparison of clinical results in brain scanning using germanium semiconductor detectors and sodium iodide detectors.

A comparison is presented of the image quality obtained with a 70 mm Ge(Li) detector scanner and with routine techniques based on NaI (Tl) detectors. One hundred and sixty-five pairs of brain scans have been examined for which the patients have been scanned with both Ge(Li) and NaI (Tl) detectors. It is concluded that no major difficulties exist in introducing Ge(Li) scanners and that while a comparison of scans from different instruments is difficult there is evidence that improved diagnostic information may be obtained from scanners with Ge(Li) detectors.

X-linked adrenoleukodystrophy: spinocerebellar variant.

The phenotypic variability in X-linked adrenoleukodystrophy (X-ALD) can be wide and varied. Rarely, it can present with clinical signs of spinocerebellar degeneration. There are very few reported cases of selective predominant white matter disease of the cerebellum in these patients. We report a patient with a rare variant of adult onset ALD who was previously diagnosed as spinocerebellar ataxia. He was a 24-year-old male who had delayed developmental milestones, developed signs of spinocerebellar degeneration (SCD) after 10 years of Addison's disease. Serial Magnetic Resonance Imaging (MRI), revealed cerebellar and pontine white matter disease but sparing the cerebral cortex and supratentorial white matter. His diagnosis of X-ALD was subsequently confirmed by the elevated serum very long chain fatty acids. This patient illustrates the unusual clinical presentation and imaging features of X-ALD and the importance of considering X-ALD in the clinical context of spinocerebellar degeneration. Early recognition of this rare variant would allow proper genetic counselling and institution of dietary therapy and/or bone marrow transplantation.

Foetus in foetu--a case report.

A three-month old baby presented to the Paediatric Department with a problem of abdominal distension. Clinically, he had a large right abdominal mass which on investigations suggested a teratomatous lesion. At operation, a foetus-like tumour mass was located in the retroperitoneal space. A diagnosis of foetus in foetu was made. A close differential of a retroperitoneal teratoma is discussed and comparison with confirmed cases made.

Radiologic manifestations of rheumatic joint diseases in the plain radiograph.

In the assessment of radiologic manifestations of joint diseases, rheumatoid arthritis (RA) is the disease to which all others are compared. Knowledge of its characteristics form the basis of the other conditions. To understand the changes seen on the plain radiograph, it is essential to understand its pathophysiology first so that the manifestations of each disease can be appreciated more fully. Due to space constraint, I shall only discuss the main forms of rheumatic joint disease. Other examples of erosive arthropathies, although not rheumatic in origin, will also be included as they form part of the differential diagnosis of an erosive arthropathy, eg gout and psoriasis.

CT and MR findings in central pontine and extrapontine myelinolysis--a study of two patients.

Central pontine and extrapontine myelinolysis is a distinctive clinical syndrome and has characteristic CT and MR features. We describe two patients who presented with nasopharyngeal carcinoma, severe hyponatremia, and had quick correction of hyponatremia. Low T1 and high T2 signal alterations were seen in the basal ganglia and caudate nuclei in both patients whilst one of them had concommitant ventrolateral thalami and central pontine region involvement. Neurologic recovery was good in one case, and initially seen in the other patient before death resulted from septicaemia. Peripheral enhancement of the basal ganglia and caudate nuclei was seen in one patient, which we believe is a new feature.

Radiological features in a patient with Kimura's disease.

Kimura's disease is an immune mediated inflammatory disorder that usually involves the head and neck region, primarily affecting the salivary glands, adjacent muscle and regional lymph nodes. Peripheral blood eosinophilia is the norm. Clinically and radiologically, it is difficult to differentiate Kimura's disease from salivary gland malignancy, lymphoma or haemangioma. The radiological findings of a patient who presented with a left facial mass involving the left parotid gland and the adjacent muscles are discussed. We also propose that the difference in the degree of enhancement between the initial and subsequent computed tomography study done two and a half years later may be due to the development of increased fibrosis and sclerosis as the disease progresses.

Air in the cervical annulus--the lucent cleft sign.

The lucent cleft sign is a sign of soft tissue injury. It was first described as a sign of acute cervical injury but it is neither confined to cases of trauma nor the cervical region. The sign is also seen in degenerative disease and in the lumbar spine. The lucent cleft sign is seen anteriorly, as an area of hyperlucency above the superior end plate of the vertebra. It is the result of a partial tear of the annulus. In complete avulsion, the sign may be absent and the radiograph, completely normal. We report our experience of 15 patients with the lucent cleft sign. Our patients are relatively young (commonest age group 30-35 years) and the majority (10 patients) had a history of acute trauma. Four patients had non-specific (3 cervical and one lumbar) aches while in the last patient, the lucent cleft was an incidental finding. Although we only documented the disappearance of the sign in 4 patients, we believe that with healing, the sign will eventually disappear. Although the sign is transient, it is useful as it may be the only sign present in cases of trauma.

Ultrasonography and computed tomography in a clinical algorithm for the evaluation of suspected acute appendicitis in children.

AIM: To evaluate the roles and effectiveness of US and CT in a clinical algorithm for the evaluation of children with suspected appendicitis. METHODS: Patients with suspected appendicitis were prospectively evaluated with ultrasound (US), and in some cases with CT, after they were graded to have high, intermediate or low clinical likelihood for appendicitis. Imaging findings were made known to clinicians who then decided on a line of management. Patho-histological examination and clinical follow-up established the final diagnoses, which were correlated with the imaging findings. The effect of imaging on the management of patients was examined. RESULTS: Overall, the sensitivity of US was 92.9%, specificity 96.9%, accuracy 96.0%, positive predictive value 89.7% and negative predictive value 97.9%. Imaging did not affect the decision to operate in 13/14 (92.9%) patients in the high likelihood subgroup. Imaging guided the clinicians to the right management pathway in 26/30 (86.7%) patients in the intermediate group. 77/82 (93.9%) of US was truly negative in the low likelihood group. CT was performed in 12 patients because of unsatisfactory US scans or incompatibility between the US and the clinical findings. CT correctly diagnosed the presence or absence of appendicitis in all 12 patients. CONCLUSION: US and CT are accurate modalities in the diagnosis of acute appendicitis in children. US is most useful in patients with equivocal clinical findings. US should be the first modality used to evaluate children with suspected appendicitis. CT should be reserved for cases where US is sub-optimal or where the findings are inconsistent with the clinical findings.

Early local experience of ankle arthrography and its influence on management of patients with ankle injury.

Ankle arthrography was performed on 64 patients with a history of ankle injury from 21 January 1986 to 11 October 1988. There was a male predominance in the ratio of 15 to 1 and the mean age of our patients was 22 years. A total of 65 arthrograms were obtained as one patient had bilateral ankle arthrograms. Of these, 29 arthrograms were normal. A year after completing this study, we attempted to retrieve our patients' case-notes and reviewed their subsequent management. Our results showed that multiple factors influenced the further management of our patients and arthrogram did play a role in this respect.

Occupational respiratory diseases in Singapore.

Occupational respiratory disease statistics in Singapore from 1970 to 1993 were reviewed. Silicosis was the most common occupational respiratory disease in the 1970s and 1980s. About 78% of the cases were from granite quarries. With progressive reduction in dust levels and the closure of some quarries, there has been a decline in cases. From 1990 to 1993, occupational asthma was the most common occupational respiratory disease and more cases are expected with increasing awareness of the condition. The most common causative agent was isocyanates accounting for about 34% of cases. Of the asbestosis and malignant mesothelioma cases, about 70%-80% were from the one and only asbestos cement factory. With the closure of this factory and the increasing restrictions on the use of asbestos, cases of asbestosis are expected to decline in the long term. However, malignant mesothelioma cases may continue to surface because of the long latent period and the potential risk with low and brief exposures to asbestos. It is important to probe for possible occupational exposures (both present and past) in a patient with respiratory symptoms or disease.

Diffusion weighted MR imaging in acute stroke: the SGH experience.

Cerebrovascular accident (CVA) is a leading cause of death and disability in many countries. Diffusion-weighted (DW) magnetic resonance (MR) imaging has been reported to be useful in the detection of acute strokes and as an investigative tool evaluating the therapeutic effects of neuroprotective and thrombolytic agents. The objectives of this study are to share our experience using the commercially available isotropic DW scan in imaging of acute stroke, assess its usefulness over conventional T2-weighted (T2W) scans in a busy clinical radiology unit and highlight it pitfalls. We found the rapid sub-minute DW technique well suited for ill and restless stroke patients and superior to T2W scans in many ways. It was highly sensitive to acute ischaemic lesions, made lesions easily identifiable and readily differentiated the acute lesion from a background of multiple chronic infarcts. However, there are potential pitfalls in the evaluation of small hyperacute posterior fossa strokes and venous infarcts. The major strength of this MR technique lies in its ability to diagnose hyperacute strokes and thence the potential for therapeutic thrombolysis, but unfortunately patients qualifying for the "therapeutic window" were a minority. More efforts need to be focused on public education in order for this powerful imaging modality to find its true value and contribute to viability of an effective thrombolytic programme.

Cerebral venous angioma--a misnomer?

Cerebral venous angioma (CVA) is an embryonic venous malformation. Its incidence was thought to be radiologically rare previously but with greater clinical awareness, the routine use of contrast enhanced computerised tomography (CECT) and the increasing availability of magnetic resonance imaging (MRI), it is no longer perceived to be a rare lesion. In fact, it is the commonest intracranial vascular malformation seen at autopsy. We report our experience of 15 patients with cerebral venous angiomas, 14 of whom had their lesions confirmed by cerebral angiography. Presentation was variable and non-specific. The commonest presenting symptom was headache (n = 7). Other clinical presentations included epilepsy (n = 5), intracerebral bleed (n = 4, two were thought to be due to an associated cerebral cavernous angioma and one was due to a ruptured arteriovenous malformation) and non-specific giddiness (n = 3). Six were diagnosed incidentally. Based on the angiographic findings and the relatively benign clinical course in the majority of our patients, we believe that CVA is a developmental anomaly and should not be excised routinely.

Comparison of accuracy of magnetic resonance angiography with conventional angiography: a report of 45 cases.

To investigate the accuracy of magnetic resonance angiography (MRA), compared to conventional cerebral and carotid angiography (CA), 45 patients underwent MRA within one week after CA. The MRA involves a FISP (fast imaging steady precession) pulse sequence base on three-dimensional time-of-flight phenomena at 1.0 Tesla. Repetition time of 35-40 msec, echo time of 7-11 msec and a flip angle of 15-25 degrees were used to optimise the depiction of blood flow as high intensity. Volume data were then submitted to a maximum intensity projection programme and viewed at multiple arbitrary projection angles rotating through the three orthogonal planes. Venous structures were suppressed with a presaturation slab superior to the area of interest. All significant stenoses and occlusions at the carotid bifurcation and circle of Willis were detected. Other than the carotid siphon (61.4%), the rest of the arteries have above 70% complete agreement between MRA and CA. The carotid bifurcation and basilar artery show complete agreement of 75.4% and 76.2% respectively, making MRA a simple sensitive screening procedure. This report shows that MR angiography has an important role in the evaluation of blood flow in the head and neck regions.

Portable chest radiography: comparison of high-resolution digital displays with laser printed digital film.

Computed radiology is a radiographic imaging technology that generates a conventional radiographic image in digital form. The image can be recorded on a laser sensitive film or archived to a digital storage device and displayed on a video monitor. This study was performed to evaluate the adequacy of reporting digitised images directly from the workstation. The test set consisted of portable chest images of 55 patients from the cardiothoracic intensive care unit. Normal structures and nine abnormalities were pre-selected for analysis. The radiographs and images on the video display were reviewed on two separate occasions, six months apart by two independent readers. No clinical details were supplied and the intraobserver and interobserver agreement were assessed using Kappa statistics. The overall results indicated that direct reporting from the workstation was as reliable as reporting from the laser printed copies.

Reduction in retake rates and radiation dosage through computed radiography.

The availability of computed radiography has opened the possibility of using reduced dosage for radiographs in clinical settings and reducing the retake rate. A prospective controlled study was carried out over a period of four months comparing conventional X-rays and computed radiography. The aim was to assess if computed radiography at 50% normal dosage would result in films of adequate quality and a reduced retake rate compared to conventional radiography. The number and reason for retakes in each group were recorded. Film quality comparison using only chest X-rays (CXR) in one of three positions; erect posterior-anterior (PA), anterior-posterior (AP) sitting and supine was done by a panel of radiologists. A total of 6373 conventional and 4127 digital films were analysed. The overall retake rate was lower in the computed radiography group (4.6 vs 8.2% P < 0.001) as was the retake rate due to exposure factors (0.6% vs 3.2% P < 0.01). There was a higher proportion of optimal films in the computed radiography group for erect PA and sitting AP CXR (71% vs 61% P = 0.0015 and 64% vs 9% P = 0.0009 respectively) but no difference for supine films. Computed radiography resulted in a reduced retake rate due to exposure factors leading to a reduction in the overall retake rate. Despite 50% dosage reduction, films were of better or equal quality when compared to conventional radiography.