Fatal cerebral air embolism as a complication of transbronchoscopic lung biopsy: a case report.

A rare complication of transbronchoscopic lung biopsy, namely a cerebral air embolism, is presented. The course of events following the embolic episode in the form of a fall in blood pressure, bradycardia and convulsions is documented, as is the presence of an air emboli on the CT scan of the brain with subsequent resorption of the emboli on the follow-up scan. The salient features of the case are the rarity of the complication and the excellent temporal depiction of imaging findings on CT scan demonstrated as resorption of air emboli and subsequent watershed territory infarcts.

Intercostal lung herniation--depiction on spiral CT.

Computed tomography (CT) is the imaging modality of choice for the demonstration of intercostal lung herniation. The use of forced expiration and Valsalva's manouevre during CT scanning has been recommended in selected cases. We report a case of intercostal lung herniation, demonstrated only on coughing on spiral CT.

Hyperimmunoglobulinaemia E syndrome: pulmonary imaging features.

Hyperimmunoglobulinaemia E (hyper-IgE) syndrome (Job's syndrome) is a rare disease that presents with recurrent cutaneous and sinopulmonary infections, and which begins in infancy and is associated with extreme hyper-IgE. The pulmonary imaging features typically consist of recurrent alveolar lung infections, pneumatocoeles and, occasionally, pneumothorax. Various other causes of pneumatocoeles in children can be excluded on the basis of clinical history and other data. Computed tomography may add valuable information for the management of these patients.

A retrospective analysis of spontaneous sphenoid sinus fistula: MR and CT findings.

BACKGROUND AND PURPOSE: The sphenoid sinus is rarely implicated as a site of spontaneous CSF fistula. We undertook this study to evaluate the potential etiopathogenesis of spontaneous CSF fistula involving the sphenoid sinus and to review the imaging findings. METHODS: We retrospectively reviewed the imaging findings of 145 cases of CSF fistula from our departmental archives (August 1995 through August 1998). Fifteen (10%) patients had CSF fistulas involving the sphenoid sinus. Eleven (7%) patients had spontaneous CSF fistulas, whereas in four patients, the CSF fistulas in the sphenoid sinus were related to trauma. Of the 11 patients, nine underwent only plain high-resolution CT and MR cisternography. One patient additionally underwent contrast-enhanced CT cisternography, and one other patient underwent MR cisternography only. For each patient, the CSF fistula site was surgically confirmed. The MR imaging technique included T1-weighted and fast spin-echo T2-weighted 3-mm-thick coronal sequences obtained with the patient in the supine position. The plain high-resolution CT study included 3-mm-thick, and sometimes 1- to 1.5-mm-thick, coronal sections obtained with the patient in the prone position. Similar sections were obtained after injecting nonionic contrast material intrathecally via lumbar puncture for the CT cisternographic study. We evaluated each of the 11 patients for the exact site of CSF leak in the sphenoid sinus. We also determined the presence of pneumatization of lateral recess of the sphenoid sinus, orientation of the lateral wall of the sphenoid sinus, presence of arachnoid pits, presence of brain tissue herniation, and presence of empty sella in each of these patients. RESULTS: The exact sites of the CSF fistulas were documented for all 11 patients by using plain high-resolution CT, MR cisternography, or CT cisternography. In nine (82%) patients, the sites of the CSF fistulas were at the junction of the anterior portion of the lateral wall of the sphenoid sinus and the floor of the middle cranial fossa. In the remaining two (18%) patients, the sites of the CSF fistulas were along the midportion of the lateral wall of the sphenoid sinus. Of these 11 patients, one had bilateral sites of the CSF fistula at the junction of the anterior portion of the lateral wall of the sphenoid sinus with the floor of the middle cranial fossa. In nine (82%) patients, the presence of brain tissue herniation was revealed, and this finding was best shown by MR cisternography. Ten (91%) patients had extensive pneumatization of the lateral recess of the sphenoid sinus, with an equal number having outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus. In seven (63%) patients, the presence of arachnoid pits, predominantly along the anteromedial aspect of the middle cranial fossa, was shown. In seven (63%) patients, empty sella was shown. For comparison, we reviewed the CT studies of the paranasal sinuses in 100 age-matched control subjects from a normal population. Twenty-three had extensive lateral pneumatization of the sphenoid sinus along with outward concavity of the inferior portion of the lateral wall. None of these 23 patients had arachnoid pits. CONCLUSION: The sphenoid sinus, when implicated as a site of spontaneous CSF leak, yields a multitude of imaging findings. These are extensive pneumatization of the lateral recess of the sphenoid sinus, outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus, arachnoid pits, and empty sella. Considering the normative data, we speculate that this constellation of findings could play a role in the etiopathogenesis of spontaneous sphenoid sinus fistulas. Our findings also show the efficacy of noninvasive imaging techniques, such as plain high-resolution CT and MR cisternography, in the evaluation of sphenoid sinus CSF leak. Our data also suggest that spontaneous sphenoid sinus CSF leak is not an uncommon occurrenc

Gamma-knife radiosurgery for trigeminal neuralgia.

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70-80 Gy was delivered to the trigeminal root entry zone, 2-4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5-16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.

Pneumocephalus secondary to colonic perforation by ventriculoperitoneal shunt catheter.

We present a case of colonic perforation as a complication arising from ventriculoperitoneal shunt catheter. A 58-year-old woman with a ventriculoperitoneal shunt catheter inserted for obstructive hydrocephalus was admitted to hospital with signs and symptoms of meningitis. CT showed an air-fluid level within both lateral ventricles, raising the possibility of colonic perforation since no other aetiology for the pneumocephalus could be found. The CT demonstration of the colonic perforation played a crucial role in patient management.

Evaluation of high-resolution CT and MR cisternography in the diagnosis of cerebrospinal fluid fistula.

PURPOSE: We undertook this study to determine the accuracy of MR cisternography and plain high-resolution CT as a noninvasive alternative to CT cisternography in the diagnosis of CSF fistula in patients with clinically suspected CSF rhinorrhea. METHODS: Forty-five consecutive patients with clinically suspected CSF rhinorrhea were examined prospectively for CSF fistula with MR cisternography and plain high-resolution CT. Twenty-one patients also underwent CT cisternography. The MR imaging technique included 3-mm thin-section T1-weighted coronal sequences and fast spin-echo T2-weighted coronal, axial, and sagittal sequences in the supine position. The plain high-resolution CT study included 3-mm and sometimes 1- to 1.5-mm thin coronal sections in the prone position. Similar sequences were used after injecting nonionic contrast material intrathecally via lumbar puncture for the CT cisternographic study. The plain high-resolution CT and MR cisternographic studies were compared with results of CT cisternography; surgical findings were used as the standard of reference. RESULTS: Plain high-resolution CT successfully depicted the presence or absence of CSF fistula in 42 of 45 patients, whereas MR cisternography was correct in 40 patients. MR cisternography or plain high-resolution CT correctly showed the site(s) of CSF fistula leakage in 36 of the 38 cases proved surgically. The combined techniques also correctly indicated the absence of CSF leakage in seven cases, six of which were confirmed at CT cisternography. Both MR cisternography and high-resolution CT failed to definitively locate the CSF fistula in two patients. High-resolution CT was accurate in 93% of patients, whereas MR cisternography was accurate in 89% of patients. The combination of high-resolution CT and MR cisternography was accurate in 96% of patients. CONCLUSION: In the presence of clinically diagnosed CSF leakage, the combination of MR cisternography and plain high-resolution CT is highly accurate in locating the site and extent of CSF fistula and should be considered a viable noninvasive alternative to CT cisternography.

Cerebrospinal fluid otorhinorrhea in patients with defects through the lamina cribrosa of the internal auditory canal.

We describe three patients with bilateral cerebrospinal fluid (CSF) otorhinorrhea with unilateral progressive hearing loss in whom CT showed the defect to be located in the lamina cribrosa of the internal auditory canal. CT cisternography showed the CSF fistula in two of the three patients who had Mondini malformation, whereas the CSF fistula was obvious on the plain high-resolution temporal bone CT study in the third patient, who had a posttraumatic (nonsurgical) fracture of the lamina cribrosa. Fast spin-echo T2-weighted coronal MR cisternography also showed the site of leakage in the third patient. In the presence of an intact tympanic membrane, the CSF egressed to the nose via the eustachian tube in all three patients.

Magnetic resonance angiography.

The field of MRA has progressed to a stage at which several clinical applications are of obvious value, including the diagnosis of cerebral aneurysms, venous disorders and disease of the carotid bifurcation. Additionally spin echo images are useful in studying the parenchyma and this together with MRA works to be an excellent diagnostic package in the presurgical workup of patients with cerebral vascular abnormalities. With further technical improvements, it seems likely that important applications of MRA will also be found in the diagnosis of peripheral artery disease, stenosis of the renal artery and ischemic heart disease. With the advent of fast imaging techniques like echoplanar imaging, the ability image the coronary and renal arteries accurately seems possible in the near future. At present, however the lack of optimal spatial resolution and the presence of flow artifacts precludes the use of this technique for imaging the vasculature with an accuracy comparable with conventional angiography. The advent for contrast 3-D CT angiography has resulted in a technique of studying the intracranial vessels immediately after assessing for the presence of subarachnoid hemorrhage. It is superior to MRA in demonstrating the actively filling and thrombused portions of giant, partially thrombused aneurysms and in planning the surgical approach in relation to bony landmarks. Though there are daunting obstacles, with continuous ongoing clinical research and the added inputs from a dramatically changing computer technology, MRA is all set to be an imaging study of great promise that may eventually replace diagnostic catheter angiography in most clinical situations.

Tubercular splenic abscesses in a patient with AIDS.

Opportunistic infections are common in patients with AIDS. There is an increasing incidence of tuberculosis, especially extrapulmonary tuberculosis. Splenic abscesses is one such, though rare, extrapulmonary manifestation. We report such a case discuss the diagnosis and treatment in these cases.