Felix O. Kolb

Assessment of metabolic bone diseases by quantitative computed tomography

Advances in the radiologic sciences have permitted the development of numerous noninvasive techniques for measuring the mineral content of bone, with varying degrees of precision, accuracy, and sensitivity. The techniques of standard radiography, radiogrammetry, photodensitometry, Compton scattering, neutron activation analysis, single and dual photon absorptiometry, and quantitative computed tomography (QCT) are described and reviewed in depth. Results from previous cross-sectional and longitudinal QCT investigations are given. They then describe a current investigation in which they studied 269 subjects, including 173 normal women, 34 patients with hyperparathyroidism, 24 patients with steroid-induced osteoporosis, and 38 men with idiopathic osteoporosis. Spinal quantitative computed tomography, radiogrammetry, and single photon absorptiometry were performed, and a spinal fracture index was calculated on all patients. The authors found a disproportionate loss of spinal trabecular mineral compared to appendicular mineral in the men with idiopathic osteoporosis and the patients with steroid-induced osteoporosis. They observed roughly equivalent mineral loss in both the appendicular and axial regions in the hyperparathyroid patients. The appendicular cortical measurements correlated moderately well with each other but less well with spinal trabecular QCT. The spinal fracture index correlated well with QCT and less well with the appendicular measurements. Knowledge of appendicular cortical mineral status is important in its own right but is not a valid predictor of axial trabecular mineral status, which may be disproportionately decreased in certain diseases. Quantitative CT provides a reliable means of assessing the latter region of the skeleton, correlates well with the spinal fracture index (a semiquantitative measurement of end-organ failure), and offers the clinician a sensitive means of following the effects of therapy.

Quantitative computed tomography for spinal mineral assessment: current status.

Quantitative CT (QCT) is an established method for the noninvasive assessment of bone mineral content in the vertebral spongiosum and other anatomic locations. The potential strengths of QCT relative to dual photon absorptiometry (DPA) are its capability for precise three-dimensional anatomic localization providing a direct density measurement and its capability for spatial separation of highly responsive cancellous bone from less responsive cortical bone. The extraction of this quantitative information from the CT image, however, requires sophisticated calibration and positioning techniques and careful technical monitoring.

Inorganic phosphate treatment of nephrolithiasis

Abstract We report the results of long-term inorganic phosphate therapy in 47 patients suffering from recurrent calcium-containing urinary calculi. Forty-five patients had hypercalciuria before treatment. Phosphate therapy had no effect on urinary calcium excretion or stone passage but did appear to reduce the need for lithotomy. The stone passage-removal rate in the 5 years before therapy was 1.3 per patient per year and fell to 0.8 in the years of treatment (mean 5.5 years). The lithotomy rate fell from 0.12 per patient per year to 0.04 with treatment (p

Hepatolenticular degeneration: Clinical, biochemical and pathologic study of a patient with fulminant course aggravated by treatment with BAL and versenate

Abstract A case of hepatolenticular degeneration with several unusual features is reported. Clinically, the course was marked by insidious onset with mental symptoms, later by major seizures with focal electroencephalographic abnormality, and terminally by fever and an allergic skin rash. Biochemical studies revealed the usual abnormalities found in this disorder with a marked diminution of ceruloplasmin, hypercupriuria, increased copper in tissue and aminoaciduria. Pathologic study revealed disseminated brain lesions which correlated well with the clinical picture of multiple system involvement. Of special interest was the finding of acute and subacute hepatic necrotic lesions. These lesions were chronologically related to the period of treatment with dimercaprol (BAL) and calcium disodium ethylenediaminetetraacetic acid (versenate). The use of these drugs also coincided with the acute febrile terminal course. Both the adverse clinical response and the toxic hepatic lesions appeared to have been aggravated or precipitated by the drug therapy.

Chlordiazepoxide and cystinuric calculus.

To the Editor.— In a previous PRELIMINARY COMMUNICATION ( 205 : 846,1968) from this laboratory, Fariss and Kolb reported that chlordiazepoxide hydrochloride (Librium) appeared to have a crystalretarding effect in six patients with cystinuria. These outpatient studies were carried out on spot urine specimens using a qualitative evaluation of crystalluria. In a subsequent double-blind study of 12 cystinuric patients, using quantitative measurements of cystine excretion and also a method to quantitate cystine crystal formation at various concentrations and temperatures, chlordiazepoxide did not affect (1) the appearance and degree of spontaneous crystalluria, (2) the daily excretion of cystine, (3) the solubility of cystine in urine, or (4) the rate of crystallization of cystine from supersaturated urine specimens. These data have been submitted for publication. There appears to be a factor retarding crystal formation in cystinuric patients which is more pronounced in concentrated than in dilute urine. This may account for the intermittent occurrence