Characterization of intracranial mass lesions with in vivo proton MR spectroscopy

PURPOSE

To assess the use of in vivo proton MR spectroscopy for characterization of intracranial mass lesions and to ascertain its reliability in grading of gliomas.

METHODS

One hundred twenty patients with intracranial masses were subjected to volume selective spectroscopy using stimulated echo acquisition mode (echo time, 20 and 270 milliseconds) and spin echo (echo time, 135 milliseconds) sequences. The intracranial lesions were grouped into intraaxial and extraaxial, as judged with MR imaging. Assignment of resonances was confirmed in two samples each of brain abscess, epidermoid cyst, and tuberculoma using ex vivo high-resolution MR spectroscopy.

RESULTS

The in vivo spectra appeared distinct compared with normal brain in all the cases. All high-grade gliomas (n = 37) showed high choline and low or absent N-acetyl-L-aspartate and creatine along with lipid and/or lactate, whereas low-grade gliomas (n = 23) were characterized by low N-acetyl-aspartate and creatine and high choline and presence of only lactate. N-acetyl-aspartate/choline ratio was significantly lower and choline/creatine ratio was significantly higher in high-grade gliomas than in low-grade gliomas. Presence of lipids suggested a higher grade of malignancy. All metastases (n = 7) showed lipid and lactate, whereas choline was visible in only four cases. Epidermoids showed resonances from lactate and an unassigned resonance at 1.8 ppm. Meningiomas could be differentiated from schwannomas by the presence of alanine in the former. Among the infective masses, pyogenic abscesses (n = 6) showed resonances only from cytosolic amino acids, lactate, alanine, and acetate; and tuberculomas (n = 11) showed only lipid resonances.

CONCLUSIONS

In vivo proton MR spectroscopy, helps in tissue characterization of intracranial mass lesions. Spectroscopy is a reliable technique for grading of gliomas when N-acetyl-aspartate/choline and choline/creatine ratios and presence of lipids are used in combination.

Unusual MR features in a case of completely thrombosed giant aneurysm of the posterior cerebral artery

An unusual case of completely thrombosed giant aneurysm of the left posterior cerebral artery, showing much more loss of signal on T2-weighted images compared with T2*-weighted images in the periphery of the thrombus is presented. Possible mechanism of this preferential signal loss on T2-weighted images is discussed.

A comparative study of noise levels in some residential, industrial and commercial areas of Delhi

The measurements of noise levels in residential, industrial and commercial areas in the capital city of India, Delhi, were carried out in the month of March and April, 1992. Six sites in residential areas, four in industrial areas and nine in commercial areas were chosen, which were situated in different parts of Delhi. The results of statistical analysis of sound pressure levels show that commercial areas have the highest noise levels followed by industrial and residential areas. Spectral distribution of noise at octave band frequencies have also been presented for the above mentioned areas.

Markov random field for tumor detection in digital mammography

A technique is proposed for the detection of tumors in digital mammography. Detection is performed in two steps: segmentation and classification. In segmentation, regions of interest are first extracted from the images by adaptive thresholding. A further reliable segmentation is achieved by a modified Markov random field (MRF) model-based method. In classification, the MRF segmented regions are classified into suspicious and normal by a fuzzy binary decision tree based on a series of radiographic, density-related features. A set of normal (50) and abnormal (45) screen/film mammograms were tested. The latter contained 48 biopsy proven, malignant masses of various types and subtlety. The detection accuracy of the algorithm was evaluated by means of a free response receiver operating characteristic curve which shows the relationship between the detection of true positive masses and the number of false positive alarms per image. The results indicated that a 90% sensitivity can be achieved in the detection of different types of masses at the expense of two falsely detected signals per image. The algorithm was notably successful in the detection of minimal cancers manifested by masses </=10 mm in size. For the 16 such cases in the authors' dataset, a 94% sensitivity was observed with 1.5 false alarms per image. An extensive study of the effects of the algorithm's parameters on its sensitivity and specificity was also performed in order to optimize the method for a clinical, observer performance study.

Cystic intracranial mass lesions: possible role of in vivo MR spectroscopy in its differential diagnosis

Thirty-four patients showing cystic intracranial mass lesions on MR imaging were evaluated by in vivo proton MR spectroscopy (MRS) with the aim of detecting lesion-specific spectral patterns that may assist imaging in better tissue characterization. In vivo spectroscopy was performed using stimulated echo acquisition mode with echo times 20 and 270 m in all, and spin echo with echo time 135 m in 11 patients. All primary neoplasms (intra-as well as extra-axial) showed choline (3.22 ppm) resonance along with lipid and/or lactate (1.3 ppm). It was not possible to grade cystic gliomas based on N-acetyl asparate-to-choline ratio. High-grade gliomas (n = 8) showed lipid/lactate and low-grade gliomas (n = 6) showed only lactate. Seven patients with brain abscess showed resonances only from acetate (1.92 ppm), lactate (1.3 ppm) and alanine (1.5 ppm). Two cases of metastatic adenocarcinoma showed only lipid/lactate. In 7 patients with epidermoid cyst, lactate along with an unassigned resonance at 1.8 ppm was observed and could be easily differentiated from arachnoid cysts (n = 2), which showed only minimal lactate. A case of cystic meningioma could be differentiated from cystic schwannoma by the presence of alanine in the former. It is concluded that MR imaging, when combined with in vivo MRS, may help to better characterize intracranial cystic mass lesions.

Primary brain lymphoma. A brief review of clinical aspects and management

Primary C.N.S. lymphoma is a rare tumor. Five such cases were treated in our clinic between January, 1991, and October, 1993. Four patients had tumor decompression and one had total resection. All of them received radiotherapy (radiation dose 40 Gy) and chemotherapy. One patient expired during the immediate postoperative period. Four patients showed a disappearance of the tumor on CT scan after the complete course of therapy of 9 months. Three patients showed recurrence intracranially at 15, 12, and 10 months. All patients died during follow up except one, who has been alive without recurrence for 10 months. Median survival was 13 months.

Serum magnesium: a prognostic tool of acute myocardial infarction

In an attempt to find the prognostic value of serum magnesium in various complications, serum magnesium was estimated spectrophotometrically, in patients of acute myocardial infarction. There was a statistically insignificant difference in serum magnesium levels of complicated group of patients (1.627 +/- 0.192 mg/100 mL) and those who had uneventful recovery (1.412 +/- 0.132 mg/100 mL). However, this difference was highly significant when compared between control group (2.514 +/- 0.16 mg/100 mL) and complicated and uncomplicated cases separately. It was also observed that serum magnesium levels were lowest in patients who died due to major arrhythmias and cardiogenic shock followed by patients who had arrhythmias (especially ventricular tachycardia) and pump failure. The routine use of iv magnesium is recommended within first few hours of acute myocardial infarction to reduce mortality, arrhythmias and pump failure.

Efficacy of combined chelation in lead intoxication

The combination of a bone lead mobilizer, viz., CaNa2EDTA, and a soft tissue depleter such as meso-2,3-dimercaptosuccinic acid (DMSA) or the sodium salt of 2,3-dimercapto-1-propane-sulfonic acid (DMPS) was investigated for its efficacy to enhance the excretion of lead, to reduce its body burden, and to reverse certain lead-induced biochemical alterations by either of them alone in rats. The administration of CaNa2EDTA or DMSA was more effective than that of DMPS, and the combination of CaNa2EDTA and DMSA was more efficient than that of CaNa2EDTA and DMPS or the individual chelators in enhancing urinary/fecal excretion of lead, in reducing hepatic, renal, and femur concentration of lead, and in restoring lead-induced inhibition of blood delta-aminolevulinic acid dehydratase and increase in blood zinc protoporphyrin and urinary delta-aminolevulinic acid levels. The brain lead was depleted by DMSA only, but the combined chelation failed to improve upon the ability of DMSA. However, chelation therapy increased diuresis and tissue depletion of zinc.

Hemifacial spasm and cerebellopontine angle epidermoid: case report and review

A case with hemifacial spasm with tinnitus due to right cerebellopontine angle epidermoid is reported. The tumour was supposed to have caused the displacement of the part of anterior inferior cerebellar artery in the vicinity of the root exit zone of the ipsilateral facial nerve. Near total removal of the tumour along with microvascular decompression was done and the patient was completely relieved of his symptoms. The incidence of hemifacial spasm due to cerebellopontine angle epidermoid is extremely low. The cause of such an association is discussed and relevant literature is reviewed.

Influence of dietary iron deficiency on nickel, lead and cadmium intoxication

The influence of dietary iron deficiency on acute nickel, lead or cadmium toxicity as reflected by the induction of hepatic, renal, and intestinal metallothionein (MT), disposition of the metals and alterations in hematological parameters, was investigated in young rats to ascertain whether the toxic effects of these metals modify under anemic conditions. The administration of Cd induced hepatic, renal and intestinal MT while that of Ni or Pb induced hepatic MT only. While dietary Fe deficiency did not affect MT induction by Cd, it enhanced the synthesis of renal and intestinal MT by Ni and Pb. The accumulation of Pb in liver and kidney and that of Cd in liver only, were enhanced by Fe deficiency; the tissue deposition of Ni remained unaffected by Fe deficiency. The induction of hepatic MT by Ni, Pb or Cd appears to be related to the concomitant rise in the hepatic Zn, Ca and Fe levels in normal rats. However, dietary Fe deficiency increased the hepatic Zn in response to Ni or Cd and the hepatic Ca in response to Pb administration.

Tuberculous radiculomyelitis (arachnoiditis): myelographic (and CT myelographic) appearances

Tuberculous radiculomyelitis (arachnoiditis) remains one of the important causes of paraplegia in India. The diagnosis usually rests on clinical history and examination, and on laboratory findings in the cerebro-spinal fluid (CSF). Few descriptive reports are available of the myelographic appearance, with water-soluble contrast media, in tuberculous radioculomyelitis (arachnoiditis). A retrospective review of 21 myelograms and 10 computed tomographic (CT) myelograms, in 14 patients with tuberculous radiculomyelitis, was carried out, with a view to describing, in detail, the radiographic features. An attempt was made to assess the use of the radiologic procedures in diagnosis and follow up in these patients. Conventional myelographic findings included block (8/14), irregular subarachnoid space (9/14), filling defects (8/14), sluggish contrast flow (2/14), root thickening (3/14) and atrophic cord (2/14). Computed tomographic myelography showed reduced contrast density in portions of the opacified CSF ring around the cord in affected region (6/7) and, in addition, demonstrated septa and adhesions. Intravenous contrast CT was not found to be useful (2/2). Follow-up studies showed partial resolution (3/6), deterioration (1/6) and status quo of radiological findings (2/6). Although these changes can be seen in chronic radiculomyelitis (arachnoiditis) from other causes, such as leukaemic infiltration/lymphoma, other chronic central nervous system infections and iatrogenic causes, including repeated intrathecal injections, conventional myelography appeared to be useful for diagnosis and follow up in tuberculous radiculomyelitis (arachnoiditis).

Occipital-axis posterior wiring and fusion for atlantoaxial dislocation associated with occipitalization of the atlas. Technical note

The authors present their technique of occipital-axis posterior wiring and fusion for atlantoaxial dislocation associated with an occipitalized atlas. The technique consists of drilling a 3 x 1-cm horizontal groove in the occipital bone 1 cm posterior to the foramen magnum and building up a bony bridge along the posterior margin of the foramen magnum. This bony bridge is referred to as an "artificial atlas." Conventional wiring and fusion is performed between the artificial atlas and the C-2 lamina, interposing a strut bone graft. Since the compression force on tightening the wire is vertical, a very high degree of stability for the occipital-C-2 complex is achieved, facilitating early mobilization without postoperative redislocation.

Variable IgH chain enhancer activity in Burkitt's lymphomas suggests an additional, direct mechanism of c-myc deregulation

The deregulation of the c-myc gene in small non-cleaved cell lymphomas (SNCL) with 8;14 translocations is thought to be due to the juxtaposition of this gene with the IgH chain locus, but exactly how the Ig locus contributes to the deregulation is unclear. One widely considered hypothesis is that Ig gene enhancers, when moved near c-myc, might stimulate inappropriate transcription of this gene. To evaluate this hypothesis, we have tested the ability of the two known H chain enhancers, the JH-C mu intronic enhancer and the 3' alpha enhancer, to support transcription from c-myc promoters, by using transient transfection assays in a panel of 32 SNCL cell lines with 8;14 translocations. The activity of the JH-C mu intronic enhancer varied widely among the cell lines tested and correlated with the presence of nuclear factors binding to the E4/octamer regions of the enhancer. The 3' alpha enhancer was much less active than the intronic enhancer in all of our cell lines and seems unlikely to account for the c-myc deregulation (although the enhancer we tested was from the rat, because the human homologue is unidentified at present). A marked difference was also seen in the ability of individual cell lines to support transcription from the unenhanced c-myc constructs. Cell lines supporting the lowest enhancer activity tended to support the highest level of transcription from unenhanced c-myc promoters. The differences in transcription from c-myc promoters were confirmed by stably transfecting constructs containing c-myc promoters in SNCL cell lines. Our data strongly suggest that the importance of Ig enhancers for c-myc deregulation varies markedly in different cell lines and that, for many, trans-acting regulators of the c-myc promoters are as important or more important, than Ig enhancers in the deregulation of the c-myc gene.

Variable IgH chain enhancer activity in Burkitt's lymphomas suggests an additional, direct mechanism of c-myc deregulation

The deregulation of the c-myc gene in small non-cleaved cell lymphomas (SNCL) with 8;14 translocations is thought to be due to the juxtaposition of this gene with the IgH chain locus, but exactly how the Ig locus contributes to the deregulation is unclear. One widely considered hypothesis is that Ig gene enhancers, when moved near c-myc, might stimulate inappropriate transcription of this gene. To evaluate this hypothesis, we have tested the ability of the two known H chain enhancers, the JH-C mu intronic enhancer and the 3' alpha enhancer, to support transcription from c-myc promoters, by using transient transfection assays in a panel of 32 SNCL cell lines with 8;14 translocations. The activity of the JH-C mu intronic enhancer varied widely among the cell lines tested and correlated with the presence of nuclear factors binding to the E4/octamer regions of the enhancer. The 3' alpha enhancer was much less active than the intronic enhancer in all of our cell lines and seems unlikely to account for the c-myc deregulation (although the enhancer we tested was from the rat, because the human homologue is unidentified at present). A marked difference was also seen in the ability of individual cell lines to support transcription from the unenhanced c-myc constructs. Cell lines supporting the lowest enhancer activity tended to support the highest level of transcription from unenhanced c-myc promoters. The differences in transcription from c-myc promoters were confirmed by stably transfecting constructs containing c-myc promoters in SNCL cell lines. Our data strongly suggest that the importance of Ig enhancers for c-myc deregulation varies markedly in different cell lines and that, for many, trans-acting regulators of the c-myc promoters are as important or more important, than Ig enhancers in the deregulation of the c-myc gene.

Congenital malformations, reproductive wastage and consanguineous mating

A study was undertaken in Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, South India, to understand the relation between congenital developmental disorders and consanguinity and also reproductive wastage and consanguinity. Four hundred children with existing congenital developmental disorders were studied with regard to their consanguineous parentage and compared with 1,000 randomly selected patients attending the paediatric outpatient department. There was a significantly higher prevalence of consanguinity in the study group (p < 0.001) and greater frequency in rural areas. The common types of consanguineous marriages were between first cousins (50.6%) and uncle and niece (42.4%). Frequency of consanguinity was not significantly related to religion and caste. The mean coefficient of inbreeding was 0.056. Consanguinity had no significant effect on average pregnancy rate and reproductive wastage. The frequency of consanguinity was significantly higher especially with autosomal recessive disorders (p < 0.001), congenital heart diseases (p < 0.001), multiple malformations (p < 0.001), neurological malformations (p < 0.005), chromosomal disorders (p < 0.01), genitourinary disorders (p < 0.02) and mental retardation-developmental disorders (p < 0.02). These observations stress the need for communicating the deleterious effects of inbreeding to the public through regular health education.

C1-C2 block vertebra with fusion of anterior arch of atlas and the odontoid

A rare case of atlanto-axial block vertebra and fusion of anterior arch with the dens, with instability at the atlanto-occipital joint, is reported. The literature is briefly reviewed.

Detection of antibodies to phenolic glycolipid by ELISA in leprosy patients

Antibody (IgM) response to PGL-1, a surface glycolipid unique to Mycobacterium leprae has been studied in 25 cases each of lepromatous and tuberculoid leprosy and in 25 healthy controls. The absorbance value at 488 nm was expressed as antibody titre. Serum antibody titre was found to be significantly higher in patients than controls. Results confirm that antibody response in leprosy patients depend upon bacterial load.

Influence of dietary iron deficiency on acute metal intoxication

The influence of dietary iron deficiency on acute nickel, lead or cadmium toxicity as reflected by the induction of hepatic, renal and intestinal metallothionein (MT), disposition of the metals, and alterations in hematological parameters was investigated in rats. The administration of cadmium induced the hepatic, renal and intestinal MT while that of nickel or lead induced hepatic MT only. However, dietary iron deficiency did not influence the cadmium induced tissue MT but enhanced the ability of nickel or lead to restore the normal synthesis of renal and intestinal MT lowered under the influence of reduced body iron status. The accumulation of lead in liver and kidney and that of cadmium enhanced in liver only, while tissue deposition of nickel remained unaffected by iron deficiency. The induction of hepatic MT by three metals appears related to the concomitant rise in the hepatic zinc, calcium and iron levels in normal rats. However, dietary iron deficiency increased the hepatic zinc in response to nickel or cadmium and that of heptic calcium in response to lead.