Search PubMed⌕ Search

Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Brain MR imaging findings in two patients with Alpers' syndrome.

We describe the magnetic resonance (MR) imaging findings in two patients with the clinical diagnosis of progressive neuronal degeneration of childhood with liver disease (Alpers' syndrome). One patient showed atrophy of both occipital lobes, and one patient showed high signal intensity in deep gray matter nuclei and diffuse atrophy. Although the imaging findings were nonspecific, they correlated well with the patients' clinical findings.

Brain↗
PubMedDate not supplied

Echocardiographic demonstration of coronary sinus diverticula in patients with Wolff-Parkinson-White syndrome.

Coronary sinus (CS) diverticula have been reported to be the anatomic basis of some posteroseptal accessory atrioventricular pathways. During 1 year, 53 patients with Wolff-Parkinson-White syndrome referred to our center for catheter ablation were found to have posteroseptal or left posterior accessory pathways. The accessory pathway was associated with an anomaly of the CS in seven patients (13%), including six diverticula of the CS or its branches and one aneurysmal CS. Four of the CS diverticula were visualized by transesophageal echocardiography. Diverticular appear as echolucent, contractile pouches on the epicardial surface of the posteroseptal or posterior left ventricle that connect to the CS by an isthmus. Previous reports have suggested that accessory pathways associated with CS aneurysms have rapid conduction times and may be associated with an increased risk of rapid ventricular response during atrial fibrillation and sudden death; five of our seven patients had a short preexcited R-R interval in the range of 172 to 225 msec during atrial fibrillation. In summary, many, if not the majority, of CS diverticula associated with preexcitation can be visualized by transesophageal echocardiography.

Adolescent↗
PubMedDate not supplied

Imaging in pituitary tuberculosis.

Tuberculosis of the pituitary gland is extremely uncommon and may masquerade as a nonfunctional pituitary neoplasm. We describe imaging findings in three patients with pituitary tuberculosis and review the pattern of involvement and importance of imaging in its management. An accurate diagnosis was found to be important in these cases as antituberculous chemotherapy was curative.

Adult↗
PubMedDate not supplied

Method for analysis of polymer-supported organic compounds using mass spectrometry direct insertion.

A new approach on the use of mass spectrometry direct-insertion and a quadrupole detector for analysis of organic compounds supported in solid phase has been developed. This is a simple and efficient method based on cleavage due to the thermal-instability of the benzylic group of most commercial resins. The cleavage of supported compounds takes place in the spectrometer as a consequence of the high temperature in the instrument's chamber. These compounds are detected using a similar fragmentation pattern and a molecular ion corresponding to the same compound obtained by traditional synthesis. Polymer degradation fragments do not interfere with the spectrum interpretation, because only a few peaks and low intensities are detected. We report here the identification of different types of compounds supported in Merrifield resin, such as bis-o-aminobenzamides and simple aromatic and aliphatic compounds, using this new approach.

Journal Article↗
PubMedDate not supplied

12-epi-teuscordonin and other neoclerodanes from Teucrium bicolor.

A new neoclerodane, (12R)-epi-teuscordonin [1] has been isolated from Teucrium bicolor. The boat conformation of ring B and the configuration at C-12 in 1 were established by nOe experiments. The known diterpenoids montanin C, teucvin, 12-epi-teucvin, teupolin I, 12-epi-teupolin I, and (12S)-teucrin H-2 were also isolated from the extract. Montanin C [2] was found to be moderately toxic in the brine shrimp bioassay.

Animals↗
PubMedDate not supplied

Confirmation of location of epidural catheters by epidural pressure waveform and computed tomography cathetergram.

OBJECTIVE: Epidural pressure has remained a relatively unused test of physiological monitoring for the past 3 decades. It is our hypothesis that epidural pressure waveforms (EPWFs) obtained by transducing an epidural catheter (EC) can be used as a surrogate for the accurate location of the EC. The goal of this study was to validate this new method by comparing it with a more objective radiographic technique such as computed tomography cathetergram (CTC). METHODS: The EPWF and CTC were studied in 13 patients receiving continuous epidural analgesia (12 patients who had postoperative pain and 1 patient who had chronic pain). Of these 13 patients, 8 patients had reported inadequate analgesia, and 5 had reported satisfactory analgesia. First, the end of the EC was connected to a disposable pressure transducer, this was followed by a 5-mL normal saline bolus injection to ensure the patency of the EC, and the EPWF was recorded. Next, the patient was taken to an imaging suite and, after injecting contrast through the EC, the course of the catheter was imaged with computed tomography (CT). The CT images were studied by the neuroradiologist and correlated with the EPWF. RESULTS: The EPWF of 5 patients with clinically adequate analgesia revealed a pulsatile waveform on transducing the EC and a crescentic spread of contrast in the epidural space on CTC. In 8 patients with inadequate epidural analgesia, the EPWF measurement failed to show oscillations, and contrast collections were observed in the paraspinous muscles. The results of EPWF and CTC were compared using Fisher's exact test. CONCLUSIONS: The strong relationship between EPWF and CTC suggests that EPWF can be used reliably to confirm the correct placement of the EC in a selected group of patients.

Aged↗
PubMedDate not supplied

Computed tomography of calcified synovial sarcoma of the hypopharynx.

A rare case of synovial sarcoma arising in the wall of the hypopharynx is presented. Computed tomography was useful in delineating tumor extent, evaluating airway compromise, and confirming the presence of calcification within the tumor, which can be a favorable prognostic indicator.

Adult↗
PubMedDate not supplied

Lockjaw secondary to skull base osteochondroma: CT findings.

Osteochondromas arising from the long bones, pelvis, or scapulae are common. However, osteochondromas originating from the base of the skull are extremely unusual. Although these tumors are histologically benign, intracranial extension and their close proximity to the cranial nerves may require complex surgery. We present a case in which CT clearly delineated an osteochondroma arising from the base of the skull. The tumor had created a fusion with the ipsilateral coronoid process of the mandible, thus causing lockjaw.

Adult↗
PubMedDate not supplied

Meningioma of the chiasm and optic nerves: CT and MR findings.

A case of meningioma involving the optic nerves, optic chiasm, and optic tracts at presentation is reviewed. Computed tomography showed the chiasm to be engulfed by tumor, and this finding was helpful in differentiating this lesion from an optic chiasm glioma. Magnetic resonance further characterized the lesion by demonstrating the presence of a cystic component along the lateral aspect of the mass.

Cranial Nerve Neoplasms↗
PubMedDate not supplied

Comparison of dynamic and spiral CT for imaging the glottic larynx.

OBJECTIVE: Our goal was to prospectively compare dynamic CT (DCT) and spiral CT (SCT) for evaluating patients with suspected abnormalities of the glottic region and correlate the observed differences between the two techniques with phantom measurements. MATERIALS AND METHODS: Thirty-one patients suspected of having laryngeal abnormalities underwent DCT and SCT. The studies were evaluated by two head and neck radiologists for lesion detection, visualization of the paraglottic fat planes (PGFPs), motion artifact, respiratory misregistration, and overall image quality. Slice sensitivity profile (SSP) and image noise were measured for DCT and SCT for the imaging parameters used in this study. RESULTS: Artifacts due to motion and respiratory misregistration were reduced with SCT compared with DCT. Laryngeal abnormalities and the adjacent PGFPs were better visualized with DCT than SCT. With use of similar imaging parameters, SSP and image noise were both increased with SCT compared with DCT. CONCLUSION: SCT produces high quality images of the larynx with less motion and respiratory misregistration artifacts than DCT. DCT allows better visualization of lesions and subtle anatomic features of the glottic region. SCT may substitute for DCT in laryngeal imaging.

Adult↗
PubMedDate not supplied

Unusual pattern of enhancement in cryptococcal meningitis: in vivo findings with postmortem correlation.

Leptomeningeal enhancement on CT and MR imaging studies secondary to cryptococcal meningitis is an uncommon finding. In immunocompromised patients, this meningitis incites only a mild inflammatory reaction and abnormalities are often absent on imaging studies. We recently encountered two patients with cryptococcal meningitis in whom postcontrast MR imaging showed thick enhancing subarachnoid spaces. Both had cryptococcal meningitis at autopsy. In a different patient with cryptococcal meningitis, postmortem MR imaging and pathologic examinations showed that these areas of enhancement correspond to abundant mucoid material secreted by the yeasts.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Tumor volume: an independent predictor of outcome for laryngeal cancer.

PURPOSE: Other studies have shown a relationship between the volume of laryngeal tumors and local control when treated with radiation therapy. Our purpose was to determine the relationship between tumor volume, clinical staging, and several histologic abnormalities to local control in patients treated with initial surgery. METHOD: Tumor volume was calculated from pretreatment CT scans in 52 patients with squamous cell carcinoma treated surgically. The presence of perineural and lymphatic spread as well as cartilage and vessel invasion were obtained from histology. All cases had at least a 2 year clinical follow-up after initial surgery. Statistical analysis consisted of Mantel-Haneszel chi2-tests and Fisher exact test. RESULTS: Local control rate was 92%. Tumor volume and cartilage invasion were associated with local control (p < 0.05). Local control rate for tumors with volumes of < 16 cm3 was 98% compared with 40% for tumors with volumes of > 16 cm3 (p < 0.05). Evidence of cartilage invasion was associated with increased likelihood of local recurrence. There was no significant association between local control and perineural, vascular, or lymphatic tumor spread. We found a marginally significant association between clinical T-stage and local control (p = 0.05). CONCLUSION: Pretreatment CT volumes are useful in predicting local control in laryngeal carcinoma treated with surgery. Of the histologic features studied, only cartilage invasion was significant in predicting tumor control.

Adult↗
PubMedDate not supplied

Normal canals at the fundus of the internal auditory canal: CT evaluation.

PURPOSE: Knowledge of the normal anatomy of the four bony canals located at the fundus of the internal auditory canal (IAC) is necessary during evaluation of temporal bone trauma, congenital anomalies affecting the individual nerves, and some neuro-otologic surgeries. The purpose of this work was therefore to characterize the normal appearance of the four bony canals and to measure their dimensions. METHOD: A retrospective study was performed using CT studies of the temporal bones in 50 patients to identify and characterize the bony canals for the labyrinthine segment of the facial nerve (BCFN), superior vestibular nerve (BCSVN), cochlear nerve (BCNC), and the inferior vestibular nerve (singular canal; SC) located at the fundus of the IAC. All the patients underwent high resolution temporal bone CT for evaluation of uncomplicated inflammatory (n = 49) and neoplastic (n = 1) diseases involving the temporal bone. CT studies were done using 1-mm-thick contiguous sections in axial and coronal planes. Measurements of the canals were performed by one radiologist. No patient had a prior history of trauma, vertigo, and sensorineural hearing loss or facial nerve paralysis. RESULTS: The BCFN, BCSVN, and BCNC were identified in all studies, whereas the SC was seen in 93% of studies. The BCFN, BCSVN, and BCNC arise from the fundus of the IAC, whereas the SC arises medial to the fundus. Mean +/- SD measurements (in mm) of the length and width were as follows: BCFN = 2.92+/-0.48 and 0.91+/-0.28; BCSVN = 2.36+/-0.53 and 0.89+/-0.28; BCNC = 0.93+/-0.21 and 2.13+/-0.44; and SC = 3.22+/-0.73 and 0.50+/-0.14. CONCLUSION: These small canals are routinely visualized on thin section (1 mm) CT of the temporal bone and should not be confused with fractures. This study provides baseline measurements that may be used to evaluate congenital anomalies of these canals. These data may also be helpful in the presurgical evaluation of patients undergoing singular neurectomies for benign positional vertigo.

Adolescent↗
PubMedDate not supplied

Early abnormalities related to postinfarction Wallerian degeneration: evaluation with MR diffusion-weighted imaging.

PURPOSE: Wallerian degeneration (WD) is most commonly seen after cerebral infarctions and results in persistent neurological deficits. MRI may detect changes related to WD as early as 4 weeks after the insult. We sought to determine if MR diffusion-weighted imaging (DWI) detects changes of WD during the acute period that follows a cerebral infarction. METHOD: Eleven patients with cerebral infarctions underwent DWI within 72 h of the onset of symptoms. DWI was performed using a high diffusion gradient strength (B = 1,000) in a single axis and trace imaging. We reviewed all images with special attention to the signal intensity in the location of the corticospinal tracts. RESULTS: Ten patients harbored 11 middle cerebral artery (MCA) infarcts, and one patient had an anterior cerebral artery (ACA) infarction. Only one patient with an MCA infarct showed a subtle abnormality in the ipsilateral corticospinal tract. The patient with the ACA infarct showed an abnormality in the region of the corticopontine tract. CONCLUSION: As used in this study, DWI depicted presumed early WD in only 20% of instances.

Acute Disease↗