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Biomedical subjects

H M Park

Publications and source records attributed to H M Park.

16 recordsLinked to original sources

Single photon imaging computed tomography (SPECT) for localization of epileptogenic focus in patients with intractable complex partial seizures.

Interictal and ictal HIPDM-SPECT brain scans were obtained in 38 patients who eventually underwent temporal lobectomy for treatment of medically intractable complex partial seizures (CPS). Interictal studies revealed decreased regional cerebral perfusion (rCP) in the temporal lobe corresponding to the eventual site of surgery in 76% of the patients. Similarly, ictal studies demonstrated increased rCP in 91% of the patients. Of the 33 patients who had both interictal and ictal SPECT studies, 23 (70%) showed increased rCP in the ictal state and decreased rCP in the interictal state in the same temporal lobe which was subsequently removed. The SPECT scans were particularly helpful in providing confirmatory evidence for localization and in deciding to undertake temporal lobectomy in 16 patients whose EEG studies had provided less secure localization. Our experience suggests that interictal and ictal SPECT brain imaging can be easily obtained and provides reliable localizing information in the epileptic patients being considered for temporal lobectomy.

Adolescent

HIPDM-SPECT brain imaging in the presurgical evaluation of patients with intractable seizures.

We report the results of interictal and ictal HIPDM-SPECT brain imaging in 34 patients who eventually underwent temporal lobectomy for treatment of medically intractable complex partial seizures. Interictal studies revealed decreased regional cerebral perfusion (rCP) in the temporal lobe corresponding to the eventual site of surgery in 73% of the patients. Similarly, ictal study demonstrated increased rCP in 93% of the patients. In 69% of the patients, the SPECT studies were able to demonstrate both increased rCP on the ictal scan and decreased rCP on the interictal scan in the same location, corresponding to the eventual site of surgery. These results suggest that interictal and ictal SPECT brain imaging can be easily obtained and provide reliable localizing information in the presurgical evaluation of patients with medically intractable epilepsy.

Adolescent

A photoplethysmographic technique for detecting vascular compromise: a preliminary report.

We have developed a photoplethysmographic technique for monitoring early signs of vascular compromise in extremities affected by direct vessel trauma, crushing trauma, or circumferential burns. The technique consists of positioning a small infrared emitter-detector array shielded from room light over a nailbed of the affected extremity and connecting the array to standard electronic monitoring equipment, thus producing a pulse tracing very similar in contour to an arterial pressure wave. In normal volunteers, simultaneous observations of the tracing and studies of muscle blood flow using Xe133 clearance showed correspondence of disappearance of the plethysmographic signal with limb-threatening levels of ischemia produced by inflation of a blood-pressure cuff. Studies comparing this technique to compartment pressures and arterial flow determined by ultrasound Doppler measurement are continuing. Clinically, we have used this monitoring technique on 29 trauma patients thus far, including 18 with circumferential full-thickness burns of at least one extremity. We believe that these preliminary studies suggest that photoplethysmography is a valuable continuous monitor of vascular status following trauma and a reliable indicator of nutritional blood flow.

Blood Vessels

Renal hyperconcentration of 99mTc-HEDP in experimental acute tubular necrosis.

The effect of transient renal ischemia on renal concentration and distribution of 99mTc-HEDP, 99mTc-DMSA, and 99mTc-DTPA was compared in rabbits with acute tubular necrosis. Scintigrams were obtained after injection in normal rabbits or ones with unilateral or bilateral ischemia. 99mTc-HEDP concentration in ischemic tissue was 8 to 18 times normal 1--4 hours after injection, and the resulting images delineated the morphological changes in the ischemic kidneys more accurately than those obtained with DMSA or DTPA. Calcium concentration in the ischemic kidneys increased sixfold. 99mTc-HEDP may be useful in evaluation of renal failure secondary to tubular injury.

Acute Kidney Injury

Hepatic emboli following inferior vena caval ligation. Brief report.

Radionuclide venography performed by foot vein injection of 99mTc MAA and 99mTc DTPA in a 34-year-old man approximately one year after inferior vena caval ligation demonstrated an unusual collateral pathway between the veins of the lower extremities and the portal vein, and also evidence for multiple hepatic emboli. This is a newly recognized sequela of inferior vena caval ligation.

Adult

A quantitative evaluation of rheumatoid arthritic activity with Tc-99m HEDP.

In an attempt to develop a quantitative method of evaluating rheumatoid arthritic activity, Tc-99m HEDP joint uptake values and joint-to-bone ratios were studied in ten adult rheumatoid arthritic patients and 17 nonarthritic patients. A joint-to-bone activity ratio of 1.8 at the fourth hour after injection (RA Index) discriminated clinically active rheumatoid arthritic joints from control joints with 95% accuracy. Serial studies on five patients during drug trial demonstrated a positive correlation between RA Index and the clinical manifestations of rheumatoid arthritic activity. The RA Index may be a useful quantitative parameter for evaluation of rheumatoid arthritic activity following therapy.

Adult

Skeletal and reticuloendothelial imaging in osteopetrosis: case report.

Skeletal and reticuloendothelial images, using Tc-99m HEDP and Tc-99m sulfur colloid respectively, were obtained from two adult patients with osteopetrosis. Skeletal images demonstrated increased activity in multiple fracture sites, in mandibular osteomyelitis, in ends of splayed long bones adjacent to joints, and in the epiphyseal ends of short tubular bones. The remainder of the skeleton involved with osteopetrosis showed no generalized increased uptake of Tc-99m HEDP. These findings indicate that metabolic activity in this disease is abnormally increased in the usual areas of bone growth but appears normal elsewhere. Reticuloendothelial imaging showed an almost total lack of activity in the axial and peripheral skeletal marrow space. Anemia, however, was only moderate in these patients. Skeletal scintigraphy may be useful to evaluate the presence and extent of the frequent complications of osteopetrosis, namely fractures and osteomyelitis.

Adult

Localized cryptococcal osteomyelitis.

Cryptococcal infection of the skeletal system alone is rare. The authors report a case of osteomyelitis caused by Cryptococcus neoformans involving the distal humerus and skull, with roentgenographic and scintigraphic findings and pathological confirmation.

Cryptococcosis

The value of SPECT-thallium scanning in screening for myocardial contusion.

In this prospective study of 40 patients sustaining blunt chest trauma, the value of single-photon-emission computed tomography (SPECT)-thallium scanning in the prediction of morbidity due to cardiac contusion was examined. Twelve patients developed cardiac complications--arrhythmias, ventricular conduction defects, and pericarditis. The sensitivity of SPECT-thallium scans was 55.6%, and the specificity was 32.1%, with an accuracy of 37.8%. Accuracy of the initial electrocardiogram (ECG) was 85%, with a sensitivity of 91.7% and a specificity of 82.1%. Patients with a normal ECG on admission rarely developed cardiac complications. It is concluded that SPECT-thallium is not a useful screening tool in this patient population.

Adolescent