Cost drivers in endovascular pulmonary embolism interventions.

AIM: To determine the costs associated with endovascular pulmonary embolism (PE) interventions. MATERIALS AND METHODS: Procedural costs were determined utilising time-driven activity-based costing (TDABC). A multidisciplinary team created process maps describing personnel, space, equipment, materials, and time required for each procedural step. Costs and capacity cost rates were determined using institutional and publicly available financial data. RESULTS: Process maps were developed for catheter-directed thrombolysis (CDT), ultrasound-assisted thrombolysis (USAT), pharmaco-mechanical thrombectomy (PMT), mechanical-aspiration thrombectomy (MAT), and aspiration thrombectomy (AT). Total costs were CDT $3,889, USAT $9,017.10, PMT $9,565.98, AT $12,126.42, and MAT $13,748.01. Tissue plasminogen activator costs represented 46.4% of the total materials cost for CDT, 13.1% for PMT, and 10.8% for USAT. Intensive care unit costs constitute 33.4% in CDT, 13.5% in USAT, and 13.1% in PMT of the total procedure costs. Highest total procedural costs were AT and MAT with materials cost comprising 82.6% and 80.3% of total costs, respectively. CONCLUSION: Costs were greatest with large-bore mechanical aspiration and least with catheter-directed thrombolysis using a multi-side hole infusion catheter. In the absence of a reference standard technique, physician-driven device selection can substantially impact the price of a procedure. Device choice and costs must be weighed against long-term technical and clinical success to maximise the healthcare value equation.

Sodium MR Neuroimaging.

Sodium MR imaging has the potential to complement routine proton MR imaging examinations with the goal of improving diagnosis, disease characterization, and clinical monitoring in neurologic diseases. In the past, the utility and exploration of sodium MR imaging as a valuable clinical tool have been limited due to the extremely low MR signal, but with recent improvements in imaging techniques and hardware, sodium MR imaging is on the verge of becoming clinically realistic for conditions that include brain tumors, ischemic stroke, and epilepsy. In this review, we briefly describe the fundamental physics of sodium MR imaging tailored to the neuroradiologist, focusing on the basics necessary to understand factors that play into making sodium MR imaging feasible for clinical settings and describing current controversies in the field. We will also discuss the current state of the field and the potential future clinical uses of sodium MR imaging in the diagnosis, phenotyping, and therapeutic monitoring in neurologic diseases.

Intracranial involvement of giant-cell arteritis.

Two cases of giant-cell arteritis with cerebral arteritis are presented. The clinical situation and the suggestive but nonspecific angiographic features make the antemortem diagnosis possible. Greater awareness of this entity will facilitate its diagnosis and the institution of effective steroid therapy.

Cerebral infarction and migraine: clinical and radiologic correlations.

Cerebral infarction was documented by arteriography and serial computed cranial tomography (CT) in four young adults (ages 16 to 32 years) with migraine. In one case, posterior cerebral artery occlusion produced a deep parietotemporal infarct. The other three cases all had frontotemporal infarcts (one hemorrhagic) in the territory of the middle cerebral artery, without major arterial occlusion. Two infarcts produced lasting neurologic deficits; one was associated with mild, transitory symptoms, and one was asymtomatic. Laboratory investigations in two cases revealed no hematologic or cardiovascular predisposition to cerebrovascular disease. Cerebral infarction, as revealed by CT, may be more prevalent in "complicated" migraine than is generally appreciated. Such lesions may or may not develop in chronologic and anatomic relationship to the headache, and may involve either large or small arteries. The prognosis for functional recovery, based on this limited sample, seems favorable.

Occult arteriovenous malformation of the brainstem simulating multiple sclerosis.

A patient who proved to have an angiographically occult arteriovenous malformation of the brainstem and cerebellum was thought to have multiple sclerosis for 20 years, because of fluctuating brainstem symptoms and signs. Although the computed tomographic (CT) appearance of the lesion suggested a vascular malformation, because it bridged the subarachnoid space between the brainstem and cerebellum, an arteriogram was normal. This report stresses the importance of CT in making the diagnosos of occult arteriovenous malformations of the brainstem. On CT scan, these lesions generally have a high-density multiform appearance, which may enhance with contrast infusion. This lesion should be suspected clinically when there are fluctuating neurologic symptoms and signs attributable to the same neuroanatomic location within the brainstem. Surgical biopsy may confirm the diagnosis, but attempts to remove these lesions from the brainstem parenchyma are hazardous and probably are not indicated, considering the chronic and relatively benign course.

Positive rolandic sharp waves in the EEG of the premature infant.

Ninety-seven EEGs from 30 premature infants found to have multifocal white matter necrosis on ultrasound (US) or autopsy were reviewed retrospectively. Twenty infants had intraparenchymal echodensities on US that developed into cystic lesions, a finding consistent with periventricular leukomalacia; 8 had intraparenchymal hemorrhages; and 2 had white matter necrosis at autopsy. Four of these infants had no intraventricular hemorrhage. Positive sharp waves in the central (rolandic) regions (PRS) were identified in 22 of these 30 infants (73%) and in 0 of 30 age-matched controls (p less than 0.001). The presence of PRS on the EEG of the premature infant has a high correlation with white matter necrosis rather than with intraventricular hemorrhage. In all cases, this EEG pattern was present prior to the development of cavitations when echodensities were present on US.

Phase 1 clinical trial of chimeric monoclonal anti-CD4 antibody in multiple sclerosis.

We conducted an open trial of cM-T412, a chimeric monoclonal anti-CD4 antibody, in 29 patients with MS. This antibody caused a prompt and long-lasting depletion of circulating CD4 (helper/inducer) lymphocytes. The mean (+/- SE) CD4 count for the group decreased from 870 (+/- 66) cells/mm3 at baseline to 76 (+/- 11) 3 hours after treatment, and then increased to 425 (+/- 38) at 1 month after treatment and 475 (+/- 39) at 6 months after treatment. Numbers of CD8 (cytotoxic/suppressor) lymphocytes, B lymphocytes, granulocytes, and monocytes changed transiently but showed no significant long-term effects. The most common side effects were headache, nausea, myalgia, fever, and tachycardia occurring in the first few hours after treatment. No serious or unexpected infections or other significant adverse effects occurred. Kurtzke EDSS scores remained stable, and MRI scans showed less contrast enhancement 1 week after treatment. We conclude that treatment of MS patients with cM-T412 chimeric anti-CD4 antibody is well tolerated at the doses tested and produces a long-lasting, selective depletion of CD4 lymphocytes.

Arthrography using perfluorocarbon compounds.

The neat liquid and an emulsion of two perfluorocarbon compounds were injected into the knee joints of dogs and a human cadaver to investigate their applicability for arthrography. Excellent delineation of joint structures was observed for as long as 24 hours, but after 24 hours each contrast agent leaked out of the joint capsule into surrounding tissue. Light microscopy of joint tissue revealed a synovial proliferative reaction and a foreign-body granuloma reaction in surrounding tissues. No clinically apparent adverse side effects were evident in the test animals.

Time-density evaluation of the liver after iosulamide meglumine: a tissue-specific CT contrast agent.

Iosulamide meglumine, a new intravenous biliary contrast agent, was evaluated as a potential hepatic contrast agent utilizing computed tomographic scanning. Time-density data in dogs were generated following 56.7 and 75.6 mg iodine/kg body weight. The iodine was administered both as an iosulamide meglumine bolus injection and a 0.77 ml/min infusion. The greatest increase in x-ray attenuation (24 HU) was observed within 45 minutes after the 75.6 mg iodine/kg body weight infusion technique, which resulted in excellent hepatic opacification. The long duration of increased x-ray attenuation of hepatocytes produced by iosulamide meglumine would be useful in the CT detection of hepatic mass lesions which do not contain normally functioning hepatic cells.

Contrast media tonicity. Part II. Isotonic ioxaglate vs. standard renografin for IV-DSA evaluation of the carotid bifurcation, a double-blind prospective clinical trial.

Laboratory research has suggested that isotonic contrast media may be optimal for intravenous digital subtraction angiography (IV-DSA) by generating taller, narrower time-concentration curves. Clinical investigation of low osmolality contrast media has suggested that less patient discomfort is encountered with low-osmolality contrast media than with standard, high-osmolality agents. In order to directly compare isotonic contrast media with a standard hypertonic contrast media, isotonic ioxaglate (Hexabrix-20) was compared with Renografin-76 in a double-blind prospective clinical trial for IV-DSA examination of the carotid artery bifurcation. Isotonic ioxaglate produced superior contrast medium time-opacification curves and produced superior images across four scales of image quality: anatomic "openness" of the carotid bifurcation, contrast level within the carotid vessels, bone misregistration artifact over the bifurcation, and air (soft tissue) misregistration. The bilateral overall score for isotonic ioxaglate was 1.68 vs. 1.37 for Renografin-76, a 23% superiority. The bulk of the superiority occurred in the contralateral carotid artery. Over the four scales, isotonic ioxaglate was 37% better in image quality of the contralateral carotid artery bifurcation. Since the contralateral carotid artery is very often difficult to visualize during IV-DSA, isotonic ioxaglate represents a significant improvement for this imaging modality.

Some useful concepts of matched filtering in intravenous digital subtraction angiography.

Using computer calculations and assumed contrast bolus curves, several aspects of the application of temporal integration methods and matched filtering to intravenous digital subtraction angiography (IV-DSA) were studied. The topics included the improvement in signal-to-noise ratio (SNR) of the final image provided by simple integration, a comparison of the SNR performance of matched filtering and extensive integration, the degradation of SNR caused by the motion of noniodinated objects and the sensitivity of SNR to variations in DSA bolus dynamics from patient to patient. Additionally the dependence of matched filter SNR on exposure position and duration was both estimated and demonstrated with clinical DSA images. The results indicate that a substantial improvement in SNR can be obtained with only moderate integration increasing to a two X improvement for longer durations. Integration methods are able to withstand moderate durations (2 seconds) of motion and still provide image quality superior to more conventional DSA results.

A procedure for using proton magnetic resonance imaging to determine stereotaxic coordinates of the monkey's brain.

Because of great inter-individual variability in the sizes and configurations of monkey brains, consistent intracerebral stereotaxic placements are not possible when a general brain atlas is relied upon to derive placement coordinates. We describe a procedure that allows the determination of brain atlases for individual monkeys using proton magnetic resonance imaging and the translation of image coordinates to stereotaxic coordinates. The latter is accomplished by chronically implanting glass beads filled with copper sulfate into the skull to establish a plane horizontal to the stereotaxic plane and to provide reference points for zeroing stereotaxic carriers during intracerebral implants. The efficacy of this procedure was confirmed experimentally.

MR imaging of infectious spondylitis.

MR images of 14 patients with pyogenic and three patients with tuberculous infectious spondylitis were studied to develop criteria for diagnosis. T1-weighted scans, 800/20 (TR/TE), were obtained in 17 patients and T2-weighted scans, greater than 2000/30,80, were obtained in 14. In seven patients, T2*-weighted scans (gradient-recalled acquisition into steady state, 25/15/5-7 degrees [TR/TE/flip angle]) and short-T1 inversion-recovery scans (STIR), 1400/150/40 (TR/TI/TE), as well as fat and water images (using a suppression technique), were obtained. Unenhanced and gadopentetate-dimeglumine-enhanced scans were obtained in four patients. In all but two patients with pyogenic infectious spondylitis, the T1-weighted sagittal scan showed characteristic findings: narrowed disk space, low signal intensity in the marrow of at least two adjacent vertebrae, subligamentous or epidural soft-tissue masses, and erosion of cortical bone. In one patient the T1-weighted scan was normal and abnormalities could be detected only on the T2-weighted scan. The remaining patient had abnormal marrow signal on the T1-weighted scan but only in one vertebral body. On T2-weighted images the major findings were a narrowed disk space with variable signal changes, abnormal high signal in marrow of at least two adjacent vertebrae, high-signal subligamentous or epidural masses, and cortical bone erosion. The findings in the three patients with tuberculous spondylitis included areas of increased and decreased signal intensity in vertebrae on T1-weighted images. Disk spaces were relatively spared given the extent of disease. Extraosseous soft-tissue components could be large. Bone erosion was best seen on the first echo of a T2-weighted sequence and on a water image; the latter was most reliable since it had no chemical-shift artifact. The use of gadopentetate dimeglumine could obscure or clarify MR findings, depending on the situation. T1- and T2-weighted MR images should be obtained for assessment of infectious spondylitis. STIR scans are particularly helpful. Fat images can be useful in subtle presentations, since they are very sensitive to marrow replacement, and gadopentetate dimeglumine may be helpful for epidural delineation of disease.

Infantile Krabbe disease: complementary CT and MR findings.

This case report of the infantile form of Krabbe disease in a 2 1/2-month-old boy illustrates the complementary findings that may be seen on CT and MR scans. The key finding on the CT scan was increased density in a bilateral symmetrical distribution involving the thalami with extension into the centrum semiovale. The MR scan, on the other hand, more clearly showed demyelination in the brain stem and cerebellum. In cases in which this involvement is minimal or absent, the MR scan may fail to detect an abnormality, and a CT scan will, therefore, still be necessary to detect characteristic abnormalities.

Cerebrospinal fluid flow measured by phase-contrast cine MR.

PURPOSE: This prospective study was designed to establish the temporal and quantitative relationship between blood flow and cerebrospinal fluid (CSF) flow using a phase-contrast cine MR pulse sequence. METHODS: A cine phase-contrast MR pulse sequence using peripheral gating was used to measure CSF flow direction and velocity. Data were acquired continuously and interpolated into 16 images throughout the cardiac cycle. RESULTS: The timing of systolic CSF flow in the cervical subarachnoid space (SAS) correlated very closely to the brain arteriovenous blood flow difference during the cardiac cycle. This arteriovenous difference was a measure of brain expansion. Aqueduct CSF flow during the cardiac cycle differed from SAS flow in that systolic flow was delayed in comparison with systolic cervical SAS flow. The normal aqueductal oscillatory flow volume was 1.7 +/- .4 mL/min or 0.03 +/- 0.01 mL per cardiac cycle. This represented 14.5% +/- 3.1% of the total CSF flow and tissue displacement through the incisura which was 14.5 +/- 2.2 mL/min or 0.22 +/- 0.03 mL per cycle. CSF oscillatory flow volume in the cervical SAS was 39.0 +/- 4.0 mL/min or 0.65 +/- 0.08 mL per cycle. CONCLUSION: CSF flow can be measured. Results in healthy subjects show relatively low oscillatory flow through the aqueduct which is slightly out of phase (delayed) compared with SAS CSF flow.

Optimizing MR imaging for detecting small tumors in the cerebellopontine angle and internal auditory canal.

Relative resolving power was used to determine the optimal MR imaging pulse sequence for detecting small tumors of the internal auditory canal and the cerebellopontine angle. Resolving power takes into consideration these important image characteristics: signal-to-noise ratio, contrast, and spatial resolution. The study was performed on a 1.5-T magnet using a 256 X 256 matrix and a 3-mm slice thickness. The TR ranged from 400-2000 msec; the number of excitations was either two or six; and the pixel size was 0.94, 0.78, or 0.63 mm. Theoretical calculations of relative resolving power were compared with the relative resolving power of 45 control patients and 15 patients with small tumors of the cerebellopontine angle or internal auditory canal. A TR of 800 msec was optimal from theoretical calculations and proved optimal in control and tumor patients. Scans obtained with TR = 2000 msec, TE = 80 msec were inferior to short TR scans; such scans could fail to detect intracanalicular tumors. The relative resolving power in patients exceeded theoretical calculations because of greater than expected image contrast caused by low CSF signal intensity secondary to CSF pulsation.

MR and CT correlation of cholesterol cysts of the petrous bone.

Four patients with expansile cystic lesions of the petrous bone had correlative CT and MR scans. Characteristic findings were noted on MR scans obtained with T1- (TR = 400-800, TE = 25-32) and T2- (TR = 2000-3000, TE = 64-80) weighted images. These findings include an expansile cystic lesion centered in the petrous apex with high signal intensity on both the T1- and T2-weighted images, compatible with subacute or chronic hemorrhage. This signal pattern is distinct from the typical intradural epidermoid tumor, which has signal intensities similar to CSF with low signal on T1-weighted images and high signal on T2-weighted images. Surgical exploration yielded similar findings of a cyst containing free-flowing, brown watery fluid. Histologically, an inflammatory response was present as well as a variable number of cholesterol crystals. There was little identifiable capsular tissue but abundant evidence of subacute or chronic hematoma. The nomenclature of the etiology in these four cases is currently in some controversy, with some authors classifying these lesions as epidermoid or primary cholesteatomas while others call them cholesterol granulomas or giant cholesterol cysts. Whatever they are named, the MR image pattern is consistent and is dominated by findings indicative of hemoglobin breakdown products.

MR and CT in cytoplasmically inherited striatal degeneration.

A rare, cytoplasmically inherited striatal degeneration associated with Leber's optic atrophy exhibited selective symmetric low-density lesions in the putamen on the CT scan in five patients. The CT findings, however, were asymmetric (one patient) and subtle in the early phases of the disease. Occasionally, caudate lesions were demonstrable. On MR imaging, the lesions had high signal intensity on T2-weighted images and low signal intensity on T1-weighted images. This group of patients was distinguished from patients with other causes of striatal degeneration by a lack of hemispheric, brainstem, or cerebellar atrophy.

Mycotic aneurysm in angiitis associated with herpes zoster ophthalmicus.

Varicella zoster (VZ) is an unusual cause of CNS angiitis, usually occurring in older patients and immunocompromised hosts. The infection most commonly presents as herpes zoster ophthalmicus with contralateral hemiplegia. Mycotic aneurysm formation associated with VZ angiitis is rare. We report two cases of VZ angiitis with mycotic aneurysm formation (both aneurysms eventually ruptured) and one case of probable VZ angiitis with distal carotid occlusion and cerebral infarction. The CT and angiographic appearances, clinical course, and histopathology are presented.

MR imaging in an experimental model of brain tumor immunotherapy.

A murine model of implanted CNS neoplasia was used to study a new form of brain tumor immunotherapy with intralesional Corynebacterium parvum (C. parvum). Assessment of treatment protocols has been limited by the inability to assess, noninvasively, tumor burden and/or the inflammatory reaction induced in the murine brain by treatment with C. parvum. This study demonstrates that contrast-enhanced MR imaging can monitor in vivo tumor burden and the immune response to intracerebral C. parvum. KHT murine sarcoma was stereotaxically implanted into the right frontal lobe of C3H/HeN mice at doses of 10,000 and 50,000 tumor cells. The KHT sarcoma is 100% fatal in untreated mice. Therapy consisted of an intraperitoneal injection of 350 micrograms of killed C. parvum 1 day after tumor implantation followed by 70 micrograms of C. parvum stereotaxically injected into the tumor 5 days after implantation. MR imaging was performed on mice injected with saline only, C parvum only, tumor only, and tumor treated with C. parvum. C. parvum alone elicited an intense transitory mononuclear cell inflammatory reaction in the meninges, ependyma, and to a variable degree at the injection site. The inflammatory response reached a peak 2 weeks after intracerebral injection. Contrast-enhanced MR imaging was able to detect the presence and severity of C. parvum-induced inflammation, which decreased 3 weeks after intracerebral injection. The transitory nature of this type of inflammation should allow its differentiation from tumor in subjects undergoing serial scanning following intracerebral injection of C. parvum as a form of brain tumor immunotherapy.