Robert G.L. Lee

Assessment of regional cerebral blood flow (rCBF) in stroke using SPECT and N-isopropyl-(I-123)-p-iodoamphetamine (IMP).

In this study we assessed regional cerebral blood flow in patients with signs and symptoms of acute stroke using single-photon emission computed tomography (SPECT) and N-isopropyl 1-123 p-iodoam- phetamine (IMP). Twenty-five patients with acute cerebral infarction had both IMP brain perfusion studies and CT scans performed within one week of each other; 22 had positive and three had negative perfusion studies. Of the 22 patients who had positive perfusion studies, six had negative CT studies initially. In the 16 patients who had abnormal CT studies, eight of the studies depicted areas of edema that were smaller than the perfusion deficits noted on the IMP studies and eight had areas of edema that were approximately equal in size to the perfusion defect. Of the three patients with normal IMP studies, two had normal CT studies and one had a positive CT study showing a 3-ram lacunar infarction. Using eight control patients, mean count rates per tissue volume normalized for the injected dose was calculated. Similarly, the quantitative data from regions of interest in the stroke patients were calculated and compared to the control patients or to a normal region in the uninvolved hemisphere in the same patients. SPECT with IMP was used to assess regional brain perfusion in acute cerebral infarction. Perfusion abnormalities were seen in our patients when the CT scan was normal, and quantitative data could be used to approximate regional cerebral blood flow in these patients when compared to the normal patient population. Stroke Vol 15, No I, 1984

Hepatic Artery Embolization for Metastatic Endocrine-Secretin Tumors of the Pancreas:Report of Two Cases

Two patients with hormone-secreting metastatic tumors of the liver (carcinoid, islet cell) were treated with transcatheter arterial embolization. In both cases, occlusion of blood supply to the tumors was accomplished, resulting in cessation of the systemic symptoms. Arterial embolization provides another useful palliative therapy for hormone-secreting tumors of the liver.

MR imaging in myelofibrosis.

Two patients with myelofibrosis demonstrated decreased signal intensity from the bone marrow due to replacement of marrow fat with fibrosis and cellular elements.

Solitary nodular sarcoidosis

Three patients, each with a solitary lung nodule consisting of sarcoid tissue, are described. With the exception of one case where a submandibular lymph node was palpable, clinical and pathological involvement was limited to the thorax and the prognosis was highly favourable. In spite of atypical features, the absence of other causes of granulomatous inflammation suggests that these patients had sarcoidosis. What factors account for limited granulomatous reaction in this form of sarcoidosis are unknown. Previous use of corticosteroids and an age of over 40 years are two possible causes suggested by these cases.

Liver adenine nucleotide metabolism during ischemia and reperfusion of mice livers studied by phosphorous-31 nuclear magnetic resonance.

Perfusion experiments were performed at 20 degrees C and 37 degrees C to study liver adenine nucleotide metabolism during ischemia and reperfusion of mouse livers using 31P NMR. Perfusing at 8 mL/min (Krebs-Henseleit buffer), ATP was shown to be stable for 6 hours. There was a progressive decrease in the phosphodiesters (glycerophosphorycholine and glycerophosphorylethanolamine) during the 6-hour period. Liver subjected to cold ischemia at 20 degrees C showed a slow decrease in the beta ATP peak during a 42 +/- 6-minute period with a rise in the inorganic phosphate accompanied by a shift of inorganic phosphate to the high field indicating intracellular acidosis. With reperfusion, the beta ATP returned to previous levels and the inorganic phosphate shifted to its original position. During warm ischemia (37 degrees C) the ATP peak disappeared within 5 +/- 1 minute and only returned to 34% of its original value after 30 minutes of ischemia, indicating damage to a certain percentage of liver cells. When the liver was subjected to multiple short periods of cold ischemia, there was complete recovery of the ATP after six cycles. Reperfusion after each period of cold ischemia resulted in an ATP recovery consistently greater than the initial amount, which gradually decreased to preischemic levels after a short period. This suggests that there is an as yet undelineated mechanism of ATP production during ischemia that attempts to protect the cell against ischemia.

Stunted growth and hepatomegaly in diabetes mellitus.

A 17-year-old girl was admitted for evaluation of short stature, delayed puberty, diabetes mellitus, and hepatomegaly. The patient was well until age 14 months when she presented with diabetic ketoacidosis. At five years of age, she was hospitalized twice for ketoacidosis with upper respiratory infections. She was noted to have hepatomegaly, but had normal liver function studies. The short stature had been recognized, but her parents were informed that subnormal growth was typical of children with diabetes. Because the family moved frequently, at least 12 different pediatricians were consulted. For the five years prior to our evaluation, the patient had been ireated With 12 units each of NPH and regular insulin daily. She and her parents claimed that mild ketonuria and increased glucosuria had been noted only over the past two months. physical examination showed (Fig. 1) a very small, younger appearing girl with a protuberant abdomen, weighing 31.5 kg with a height of 132 cm. Blood pressure measured 120/78 mm Hg; pulse rate was 84/minute. The fundi showed mild Venous dilatation but no other changes consistent with diabetic retinopathy. The thyroid, heart, and lungs were normal. The abdomen was distended by an enlarged smooth, nontender liver, 14 cm in vertical span. Pubertal development was at Tanner Stage II. Hair growth was increased on the extensor surfaces of all extremities, and the fourth and fifth fingers bilaterally had flexion contractures. Lipodystrophy was evident at the insulin injection sites. No neurologic deficit was apparent. The hemogram was normal. Glucose and ketones were present in the urine. The patient had normal serum electrolyte, creatinine, and blood urea nitrogen concentrations; blood glucose

Nuclear Magnetic Resonance Assessment of Adenosine Triphosphate (atp) Dynamics in Ischemic Mouse Livers Perfused with Adenine and Ribose

Hepatic energy stores are essential to liver viability. We used a mouse liver perfusion model and MR spectroscopy to study the effect of adding two precursors of ATP (adenine and ribose) on ATP dynamics during ischemia and reperfusion. Using Krebs-Henseleit buffer with or without added adenine and ribose made little difference in the ATP decay rate during ischemia, but the recovery of ATP during reperfusion was more complete when adenine and ribose were added to the buffer. These findings suggest that the addition of the precursors of ATP, adenine and ribose, to perfusate after ischemia can accelerate and enhance ATP recovery.

Peripancreatic lymph node enlargement in Hodgkin's disease, non-Hodgkin's lymphoma, and pancreatic carcinoma

The distribution of enlarged lymph nodes in the upper abdomen and retroperitoneum were classified according to their relationship to the pancreas in 47 patients with non-Hodgkins lymphoma; in nine patients with Hodgkins disease; and in 40 patients with pancreatic carcinoma. Four patterns of lymph node enlargement were evident: (1) preaortic retropancreatic lymphadenopathy; (2) pancreaticosplenic lymphadenopathy; (3) isolated celiac and/or portal lymphadenopathy; and (4) diffuse extensive lymphadenopathy. Features differentiating lymphoma from primary pancreatic neoplasm are discussed.

Magnetic resonance imaging of gynecologic masses

The pelvis of 21 women with various gynecological masses were imaged with magnetic resonance (MR) imagers at 2.0 and 0.5 T. Fifteen normal individuals were used for studying the normal appearance of the female genitalia using spin echo pulse sequences with various pulse repetition (TR) and spin echo (TE) time values. Images were compared with those of the ultrasonic images, intraoperative findings, and the histopathologic examinations. The masses included simple ovarian cyst, cystadenoma, serous cystadenocarcinoma, ovarian teratoma, dysgerminoma, and uterine myoma. MR imaging was useful in demonstrating the anatomy and pathology of the cases examined in this study. It detected the internal structure of some tumors which were sonographically homogeneous. The potential of MR in staging of malignancies was demonstrated.

Magnification radiography in osteomyelitis.

Osteomyelitis often eludes early diagnosis because plain film radiography is too insensitive and radionuclide bone scanning is nonspecific. In this study, 90 diabetic patients were studied with plain film and magnification radiographs of their feet. Among the 24 patients with osteomyelitis, plain radiographs suggested the diagnosis in 14 patients and magnification radiography was diagnostic in 18 of these patients. Thus, magnification radiography offers some diagnostic advantage in patients suspected of having osteomyelitis.