Acute subarachnoid haemorrhage: is a negative CT angiogram enough?

AIM: To determine the negative predictive value of 16 channel multisection computed tomography angiography (CTA) for detecting aneurysms in spontaneous subarachnoid haemorrhage (SAH), using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: The prospectively collected cerebral angiogram database of Department of Neuroradiology, Atkinson Morley Regional Neuroscience Centre was used to identify 200 consecutive patients who had undergone DSA for SAH. Of these, 176 had undergone CTA prior to DSA. Clinical details and radiology reports were correlated and images of positive investigations reviewed. RESULTS: DSA showed one or more cerebral aneurysms in 105 (60%) patients. These were correctly reported on CTA in 100. CTA was reported negative for aneurysms in 74 patients. Of these five were false negative and had aneurysms detected on DSA. In the CTA/DSA negative group, 11 (16%) patients had classical perimesencephalic clinical syndrome and blood distribution. There were two false positives at CTA. For ruptured cerebral aneurysms, CTA had 95.2% sensitivity, 97.2% specificity, 98.1% positive predictive value, and 93.2% negative predictive value. CONCLUSION: The sensitivity and negative predictive value of CTA for ruptured aneurysms remains imperfect. Continued use of DSA is recommended in most patients with a negative CTA after acute SAH. Confirmation of a negative CTA result with DSA may not be routinely required in patients with perimesencephalic syndrome.

Serial MRI of a mycotic aneurysm of the cavernous carotid artery.

Cerebral mycotic or infective aneurysms are a rare complication of infectious illness, and such aneurysms of the intracavernous portion of the internal carotid artery are rare. They have been described as a consequence of cavernous sinus infection in an immunocompromised host, but not previously in a renal transplant recipient. We present such a case with serial MRI showing progression from arterial narrowing to aneurysm formation. Transcranial Doppler sonography of the middle cerebral artery showed distal asymptomatic embolisation from the aneurysm.

Can mild head injury cause ischaemic stroke?

Five cases of ischaemic stroke preceded by minor head trauma in children are described. All patients had striatocapsular infarction. Three had no cerebrovascular abnormality; two had turbulent flow in the proximal middle cerebral artery. None of the patients had evidence of arterial dissection or any other risk factors for stroke. All made an excellent neurological recovery. Possible mechanisms include mechanical disruption to the flow in the perforating branches of the middle cerebral artery, intimal trauma and subsequent thrombosis, or arterial spasm induced by trauma. The specific susceptibility in affected children remains unexplained; both genetic and environmental factors (for example, previous chickenpox) may be implicated.

Hyrtl's fissure.

Hyrtl's fissure is a transient anatomic landmark in the developing fetal petrous temporal bone and is usually closed by the normal progression of ossification in the 24th week of gestation. It occasionally persists into extrauterine life and has been reported as an unusual cause of a perilabyrinthine cerebrospinal fluid fistula. We present a case of a child presenting with bacterial meningitis because of a persistent Hyrtl's fissure. We have reviewed aspects of the fissure's developmental anatomy and previously published clinical cases. We have also explored the provenance of the eponym. We were unable to uncover evidence in support of the contention that Joseph Hyrtl was actually responsible for describing the structure commonly known as Hyrtl's fissure.

Intracranial dural empyema.

Intracranial dural empyema is a neurosurgical emergency with potentially devastating complications. The prognosis is adversely affected by delay in diagnosis. Modern imaging techniques, especially contrast enhanced CT and MRI, have improved the speed and accuracy of radiological diagnosis of this condition, with an associated reduction in mortality. Despite this, there may still be a delay in diagnosis, partly owing to the subtlety of early radiological signs, especially on unenhanced CT. We present cases that illustrate some of the radiological manifestations, complications and potential pitfalls in diagnosis.

Stereotactic 14G core biopsy of non-palpable breast cancer: what is the relationship between the number of core samples taken and the sensitivity for detection of malignancy?

AIM: Percutaneous 14-gauge core biopsy (CB) guided by digital stereotactic mammography is now an established technique in the investigation of women with non-palpable suspicious mammographic lesions. Diagnostic sensitivity of CB is affected both by the nature of the mammographic abnormality and by the number of core samples taken. METHODS AND RESULTS: A retrospective review of 500 women who have undergone CB in our institution showed that in 235 cases, invasive or non-invasive carcinoma was found on final surgical histology. Correlation between CB result and surgical histology revealed a significant increase in sensitivity for the diagnosis of malignancy if a larger number of cores were taken (84.3% for two cores and 90.2% for five cores vs. 97.9% for six or more cores). This trend was maintained when patients were subdivided according to mammographic abnormality, either soft tissue mass or microcalcifications. The effect on diagnostic sensitivity of increasing the number of tissue cores obtained was most pronounced in patients with microcalcifications graded as low or moderately suspicious for malignancy (70.1% for two cores and 79.1% for five cores vs 94.0% for six or more cores). The presence of an invasive component in a malignant lesion was correctly diagnosed using CB in 79.2% overall if at least six cores were taken. If the mammographic lesion was a soft tissue mass, this figure rose to 95.7%, but was only 35.7% if the visible lesion was composed of microcalcifications alone. CONCLUSION: Our series confirms the reliability of stereotactic CB in the diagnosis of breast carcinoma. Diagnostic sensitivity is improved by increasing the number of cores taken (to six or more), particularly in women with mammographic microcalcifications of an equivocal nature.

Sonographic detection and characterization of musculoskeletal and subcutaneous tissue abnormalities in sickle cell disease.

Pain due to bone marrow infarction is common in homozygous sickle cell disease (SS disease). Musculoskeletal pathology may be responsible for persistent atypical symptoms. We have assessed the frequency and ultrasound appearances of soft tissue and joint abnormalities in SS disease. SS disease patients with atypical musculoskeletal symptoms were examined with ultrasound over a 2 year period. Ultrasound findings were correlated with those at surgery or percutaneous drainage. 31 episodes in 23 patients were referred for ultrasound. There were 36 abnormalities in 18 patients: abscess (n = 15), effusions (n = 5), soft tissue induration (n = 12), fat necrosis (n = 2), haematoma (n = 1) and reactive lymph node (n = 1). Five examinations were normal. Soft tissue abnormalities in patients over the age of 14 years were associated with intramuscular injections: fat necrosis (n = 1), haematoma (n = 1), indurated soft tissue (n = 1) and abscess (n = 7). Soft tissue abnormalities with no underlying cause were seen in seven patients: abscess (n = 4), indurated soft tissue (n = 2) and fat necrosis (n = 1). Ultrasound is the imaging modality of choice for delineating these abnormalities and allows percutaneous drainage.

Adenocarcinoma of the sweat gland of the vulva: light and electron microscopic study.

A sweat gland carcinoma, a rare tumor of the skin which arose in the posterior fourchette in a 53-year-old white woman, was studied by light and electron microscopy. The tumor formed cords or small acini infiltrating into the stroma with foci of Pagetoid appearance. The cells showed poor intercellular cohesions. PAS and mucin strains were negative. Ultrastructurally the tumor cells in the periphery of the acini were firmly attached to the collagenous matrix with a few pseudopodia. A basal lamina was seen in some areas. The cytoplasm was filled with many ribosomes and moderately developed mitochondria. The bundles of microfilaments in the perinuclear zone were characteristic findings in this tumor. The ultrastructure of this tumor confirmed that this was carcinoma of the sweat gland, which closely resembled intraductal carcinoma of the breast.

The Abolition of the Lag Phase in Greening Cucumber Cotyledons by Exogenous delta-Aminolevulinic Acid.

Etiolated cucumber cotyledons treated with delta-aminolevulinic acid accumulated protochlorophyllide which was phototransformable to chlorophyll (ide). The phototransformation process in the delta-aminolevulinic acid-treated tissue was markedly temperature-dependent, consistent with the view that this protochlorophyllide must combine with the holochrome apoenzyme before phototransformation can occur.The treatment which effects lag phase removal in control tissue did not affect the course of chlorophyll (ide) accumulation in delta-aminolevulinic acid-treated tissue under either continuous or intermittent illumination. It was concluded that the lag phase in etiolated tissues must reflect the gradual development of the ability to synthesize delta-aminolevulinic acid at an appreciable rate.