The role of contrast arteriography in suspected arterial injuries of the extremities

The records of 215 patients presenting with 218 penetrating or blunt injuries to the extremities from 1977 through 1983 have been reviewed. All patients presenting with pulsatile hemorrhage, expanding hematoma, or absent distal pulses were explored immediately. Patients with injuries in close proximity to a major artery but without classical signs of arterial injury were explored routinely from 1977 through 1980. Thereafter, similar patients were evaluated initially with contrast arteriography and explored only if arteriographic abnormalities suggested arterial injury. Routine exploration of proximity injuries has been compared with selective exploration based on contrast arteriography. Sixty-one patients (group 1) underwent routine exploration for proximity injuries. Vascular injuries were detected in ten (16%) patients, while 51 (84%) of the explorations were negative. Eighty-four patients (group 2) with proximity injuries were studied arteriographically. Ten patients (11.9%) were explored on the basis of abnormal arteriograms, and eight arterial injuries were confirmed. Two (2.4%) of the 84 patients in this group had negative explorations. The use of contrast arteriography enabled the authors to reduce their negative exploration rate from 84 to 2.4 per cent in the management of proximity injuries.

MR imaging of brainstem tumors

Eighteen patients aged 4-72 years old with brainstem tumors were studied using a 0.5 T magnetic resonance (MR) imager and a third- or fourth-generation computed tomographic (CT) scanner. MR imaging showed the brainstem to be enlarged on sagittal views in all cases; exophytic growth was seen in eight. Alterations of signal intensities were shown in most cases on spin-echo sequences using 30 and 90 msec echo times and inversion recovery techniques. It was not possible to distinguish primary from metastatic tumors. The configurations and margins of the areas with abnormal signal did not appear to correlate with the clinical behavior of the tumors. CT was able to recognize brainstem tumor in only 13 of 16 cases. In the two cases of metastases, plain CT scans were normal, but enhancement was seen after administration of contrast material in one. It appears that MR imaging is sensitive in detecting tumor enlargement and abnormal signals and is superior to CT in evaluating brainstem tumors.

Magnetic resonance imaging of meningiomas

Twenty-eight patients with 32 meningiomas were studied on a 0.5-T superconductive magnetic resonance (MR) imager. This common, benign treatable tumor was more clearly seen on computed tomography (CT) than MRI in 53% of cases. This is a result of poor contrast between the tumor and the adjacent brain on all spin-echo and inversion-recovery pulse sequences. Those sequences that provide the greatest anatomic detail were best for identifying this low-contrast lesion. Inversion-recovery scans in particular demonstrated the tumor as a discrete hypointense mass (relative to nearby white matter) with excellent visualization of the dural base and white matter buckling indicative of extracerebral mass effect. Other characteristic features include: a hypointense rim because of the venous capsule (66%); mottling due to hypervascularity; a well defined edema collar that demarcates the tumor from adjacent brain; and hyperostosis with thickening of the calvaria and obliteration of its normal landmarks. MRI did not demonstrate tumor calcification but did demonstrate vascular encasement, displacement, and occlusion better than CT and as well as digital venous angiography.

MR imaging of the craniocervical junction

Craniocervical junctions in 35 abnormal and 10 normal subjects were studied with a 0.5 T superconducting magnetic resonance imaging system. Sagittal spin echo with 30 msec echo times and 500 msec repetition times constituted the most informative imaging plane and sequence. The anterior aspect of the foramen magnum was well delineated; the posterior margin was less constant in appearance. Compression and distortion of the medulla and upper cervical cord by bony and extramedullary lesions were seen easily. Intramedullary cysts were differentiated from solid tumors, but ventricular communication was evaluated less successfully because of partial-volume effect of the sections. Cerebellar ectopias were detected in some asymptomatic patients.

Results of revascularization and amputation in severe lower extremity ischemia: a five-year clinical experience

Aggressive revascularization of the ischemic lower extremity in atherosclerotic occlusive disease by femoropopliteal (FP) and femorotibial (FT) bypass or profundaplasty (P), as indicated, has been advocated by some authors for all patients. Others have recommended primary amputation, particularly for tibial occlusive disease. To clarify this clinical dilemma, we reviewed the results of 547 procedures performed during the last 5 years: revascularization in 375 (69%) instances and below-knee amputation (BKA) in 172 (31%) cases. Bypass procedures were used in 246 cases: FP in 155 (64%) and FT in 91 (37%). Reversed autogenous saphenous vein (ASV) was used preferentially in 125 (51%) cases, whereas polytetrafluoroethylene (PTFE) was used in 121 (49%) cases. P was performed in 129 instances accompanied by inflow procedures in 92 (71%) of these cases. Cumulative limb salvage (LS) exceeded bypass patency in all categories and resulted in 2- and 5-year LS rates of 83% and 81% for FP with the use of ASV and 52% and 35% for PTFE. The LS rate for FT was 53% and 47%, respectively, for ASV and 20% and 15% for PTFE. Rest pain was successfully relieved by P in 99 cases (77%), whereas healing occurred in only 51% of cases with tissue loss. The perioperative mortality rate for revascularization was 3%; 42% of the group died during follow-up, death usually resulting from complications of atherosclerosis. Of the 172 BKAs, primary healing occurred in 80%, but the perioperative mortality rate was 13%. FP and FT bypasses are preferred procedures if ASV is available, whereas use of PTFE should be limited to FP bypasses only. Rest pain is relieved by P but tissue loss should prompt consideration for bypass. BKA should be considered in cases of severe tibial disease only in the absence of a suitable ASV, as the perioperative mortality rate is high and ultimate rehabilitation (64%) is limited.

MR imaging of cerebral vascular malformations

Fifteen vascular malformations, including six supratentorial arteriovenous malformations (AVMs), three venous malformations, and six brainstem vascular malformations, were examined on 0.5 T magnetic resonance (MR) and GE 9800 and 8800 computed tomographic (CT) scanners. All the malformations were shown by MR, and the arterial and venous drainage of AVMs was precisely delineated. Hematoma was always differentiated from calcification by MR signal characteristics. Increased signal in the brain parenchyma was often seen adjacent to AVMs. The signal of blood within venous malformations altered with spin-echo techniques using various repetition times and was distinguished from rapidly flowing blood in AVMs that lacked signal in all imaging sequences. Brainstem malformations were seldom demonstrated by angiography. Hemorrhage was common and was invariably associated with multiple areas of absent signal that may have represented abnormal vessels. These appearances are distinct from those of intrinsic tumors and are probably pathognomonic of brainstem vascular malformations.

MR recognition of supratentorial tumors

Eighty patients with intrinsic tumors of the cerebral hemispheres and thalami were studied with a 0.5 T superconducting system and third- or fourth-generation computed tomographic (CT) scanners. Twenty-eight patients had histologically verified gliomas, 34 were presumed to have primary brain tumors on clinical grounds, 13 had metastases, and five were postoperative. Lesions shown on CT were equally well demonstrated on magnetic resonance (MR) imaging; more metastases were seen on MR than on CT images. MR revealed abnormal signals in 10 cases in which CT findings were equivocal. It was not possible to differentiate edema from tumor in many cases using the MR imaging sequences currently available. The histologic types of the tumors could not be determined from the MR appearances.

The assessment of skin blood flow in peripheral vascular disease by laser Doppler velocimetry

The helium-neon laser Doppler (LD) is designed to measure skin blood flow velocity (SBFV). Flow velocity and pulse wave amplitude are expressed in millivolts (mv) relative to a zero-flow reference. The authors have reviewed their initial experience in ten persons (20 limbs) without peripheral vascular disease (PVD, group I) and nine patients (12 limbs) with severe PVD (group II). The finger, palm, great toe, and forehead had a significantly (P less than 0.05) greater flow velocity than the plantar and dorsal foot, distal and proximal leg, thigh, chest, arm, and forearm. Baseline and hyperemic SBFV, measured at the great toe, were compared in groups I and II. In group I, the baseline SBFV (mv, mean +/- standard error of the mean (SEM] in the great toe was 197 +/- 38 compared with 67 +/- 12 in group-II patients (P less than 0.05). The pulse wave amplitude (mv, mean +/- SEM) was 77 +/- 14 in group I and 5.4 +/- 1.1 in group II (P less than 0.05). The time to maximal hyperemic response (seconds, mean +/- SEM) in group I was 18 +/- 1.5 compared with 150 +/- 14 in group II (P less than 0.05). LD is a sensitive indicator of changes in SBFV, allowing differentiation between normal persons and patients with PVD. The LD tracing in patients with PVD is characterized by a baseline SBFV that is significantly less than normal and also by the attenuation or absence of pulse waves. The diagnostic accuracy is enhanced by the use of reactive hyperemia.

Posterior fossa lesions: magnetic resonance imaging

Studies of 40 patients with abnormalities of the posterior fossa shown on magnetic resonance (MR) imaging were reviewed and compared with CT scans. Thirteen lesions were demonstrated on MR only. Twenty-four lesions were shown on CT but MR provided more data. Three lesions were better shown on CT than on MR. MR is superior to CT because of the lack of streak artifacts and better contrast discrimination. At least two imaging sequences are required for evaluation of the lesions.

Use of intermittent pneumatic compression of the calf in femoral venous reconstruction

Application of intermittent compression of the calf is described as an adjunct to maintain patency of femoral venous reconstruction following trauma. Its use in instances of femoral and popliteal venous reconstructions is recommended.

Effect of a potent gonadotropin releasing hormone antagonist on pulsatile testosterone and gonadotropin secretion in the male nonhuman primate

A potent gonadotropin releasing hormone (GnRH) antagonist [Ac-delta 3Pro1, pFDPhe2, DTrp3,6]-GnRH was given to adult male monkeys to determine the acute effect on pulsatile testosterone and gonadotropin secretion. Blood was drawn at 30 min intervals over 54 h without anesthesia using a mobile vest and tether assembly to support an indwelling catheter. After a 6 h control period, 0.1, 1.0, 2.0, 4.0 mg GnRH antagonist/kg bw in 1 ml corn oil sc, was given to intact adult male monkeys. The highest dose of GnRH antagonist decreased circulating testosterone within 6 h and for approximately 24-36 h duration. These data demonstrate that this GnRH antagonist can reduce serum testosterone both acutely and for intervals greater than 24 h and that the effective dose in intact animals is several-fold (up to 20 times) greater than in castrate animals.

Occlusive vascular disease in asphyxiated newborn infants

Six full-term severely asphyxiated newborn infants underwent evaluation with digital intravenous angiography. All infants were comatose and flaccid and had seizures, depressed brainstem function, and signs of intracranial hypertension. An initial brain CT scan revealed diffuse hypodensities and compressed ventricles. Follow-up noncontrast CT scans showed areas of increased attenuation. Digital intravenous angiography demonstrated venous sinus thrombosis in five infants, two of whom also had arterial thrombosis, and hypervascularity in the sixth infant. Our data document that occlusive vascular disease is a prominent feature of severe perinatal asphyxia.

Popliteal and infrapopliteal arterial injuries. Differential management and amputation rates

A 3-year clinical experience is analyzed to define preferred surgical management and amputation rates for popliteal as well as infrapopliteal arterial injuries. Ten patients with popliteal arterial trauma were successfully managed without amputation, however, five of 11 (45%) patients with infrapopliteal arterial trauma required amputation. While essentially all popliteal arterial injuries mandate repair, recommendations for repair or ligation of isolated tibial arterial injuries are based on presence of distal ischemia, the patient's associated injuries, as well as estimated operating time for reconstruction. With injury to two or three infrapopliteal arteries, distal ischemia is usually present and arterial repair indicated, unless there has been severe crush injury, prolonged delay, or extended surgery would jeopardize the patient's life. A management protocol for patients with distal ischemia related to popliteal or infrapopliteal arterial trauma should include prompt surgical intervention, liberal use of fasciotomy, intraoperative arteriography, as well as the selective use of intraluminal shunts.

Revascularization of the profunda femoris artery for limb salvage

The clinical outcome of 88 profundaplasties in 70 patients operated upon during the period 1978 to 1982 was related to indications for operation, status of arterial run-off, influence of a concomitant inflow procedure, and changes in Doppler ankle-brachial index (ABI). Operative procedures were performed for rest pain (49 limbs), ulceration (24 limbs), and gangrene (13 extremities). Primary profundaplasty (PP) was performed in 26 (29%) cases. Sixty-two procedures (71%) were inflow profundaplasties (IP) performed in conjunction with other proximal reconstructions. Overall clinical success was achieved in 67 extremities (76%). When the operation was performed for rest pain, and the arterial run-off was good, success rate was 78 per cent and 79 per cent, respectively, as compared to 51 per cent and 57 per cent for ulceration/gangrene and poor arterial run-off. For PP, satisfactory outcome was noted in 69 per cent as compared to 79 per cent in IP. In the clinically successful profundaplasties, mean preoperative ABI was 0.29 and increased significantly to 0.53 postoperatively (P = 0.04). In the clinical failures, mean preoperative ABI was 0.32, and postoperative ABI was 0.38, which was not statistically significant (P greater than 0.05). Profundaplasty is a reliable operation particularly when the indication is rest pain, and the arterial run-off is good. Poor results can be anticipated when the procedure is performed for tissue loss, or if the arterial run-off is poor. Clinical outcome for the PP and IP groups were comparable.

CT of acquired immunodeficiency syndrome

Thirty patients with acquired immunodeficiency syndrome were examined by computed tomography. In addition to systemic disease, these patients had a variety of neurologic symptoms and signs. Cerebral toxoplasmosis (six cases) was generally manifested by ring-enhancing lesions with surrounding decreased attenuation. Lymphoma (one case) exhibited a solid enhancing nodule, and progressive multifocal leukoencephalopathy (two cases) showed periventricular decreased attenuation. Atrophy (15 cases) was very common and invariably indicated a poor prognosis; the autopsy examinations of the latter cases showed degeneration of gray and white matter with features similar to cytomegalic inclusion encephalitis and subacute sclerosing encephalopathy of measles.

Digital intravenous cerebral angiography in neonates

Digital intravenous cerebral angiography was performed in 13 neonates. Injections were made either centrally into the right atrium or peripherally into a distal vein. Seven infants suffered from anoxia, one infant had clinical brain death, another had focal infarcts, and two had intracranial hemorrhage. One infant had an intracranial tumor and another had a neck tumor. Venous sinus thrombosis was seen in five of the seven anoxic infants. A total absence of intracranial arterial circulation was demonstrated in the clinically brain-dead infant. Vascularity and venous involvement by neoplasm were excellently delineated by this technique.

Femoral venous trauma: techniques for surgical management and early results

During a 4 year period (1979 through 1983), 181 major arterial (69 percent) and 81 venous (31 percent) injuries were treated surgically. Of the venous injuries, 24 (30 percent) involved the femoral veins (9 common femoral, 15 superficial femoral). Management of these femoral venous injuries included lateral venorrhaphy in 10 cases (42 percent), venous patch angioplasty in 5 cases (21 percent), end-to-end anastomosis in 4 cases (17 percent), interposition autogenous saphenous vein grafts in 3 patients (12 percent), and ligation in 2 cases (8 percent). One case that included common femoral venous ligation and one that included a failed interposition saphenous vein graft in the superficial femoral vein subsequently were managed with in situ saphenous vein bypass. For one interposition saphenous vein graft repair of the common femoral vein we utilized the spiral vein graft technique. Excluding one early death from associated injuries and one superficial femoral venous injury managed by ligation without postoperative complications, 17 of 23 (74 percent) femoral venous repairs were judged patent postoperatively (13 confirmed by venography and 4 by noninvasive testing). The adjuvant use of intermittent pneumatic calf compression and low molecular weight dextran appears to have been beneficial in maintaining patency of the femoral venous repairs. Early clinical follow-up demonstrated the presence of edema in 6 of 8 cases (75 percent) initially treated by ligation or complicated by postoperative occlusion. Early postoperative edema, present in 4 of 17 (24 percent) patients with patent venous repairs, had resolved by the time of discharge. We recommend routine repair of femoral venous injuries. When significant edema or ischemia develop following obligatory venous ligation or postoperative occlusion of a venous repair, revision or venous bypass should be considered.

Male sexual development in the nonhuman primate. III. Sertoli cell culture and age-related differences

Homogenous preparations of primary Sertoli cell cultures were obtained from the testes of the macaque of different ages. The characteristics of Sertoli cells were confirmed by electron microscopy. Sertoli cell cultures were segregated into three developmental age groups: prepubertal, pubertal, and adult. The highest response to follicle-stimulating hormone [FSH (NIH-FSH-S13) as measured by cAMP and testosterone to estradiol conversion occurred in Sertoli cells from pubertal animals, whereas the responses were diminished in cells from both younger and older animals. Specific binding of 125I-human FSH was also increased in Sertoli cells prepared from pubertal animals when compared to cells from the other two age groups. These data demonstrate: 1) the utility of primate Sertoli cells as an in vitro model, and 2) the age-related differences in monkey Sertoli cell response to FSH and to specific FSH receptor binding.

Male sexual development in the monkey. I. Cross-sectional analysis of pulsatile hypothalamic-pituitary-testicular function

Pulsatile secretion of serum gonadotropins and testosterone was studied in 46 monkeys of varying ages from 9 days of age through adult life. Although some of the hormonal analysis was longitudinal in nature, most comparisons were cross-sectional. On the basis of pulsatile secretory patterns, hCG and GnRH stimulation, skeletal age, testicular volume, and histology, we have arbitrarily defined four developmental age groups: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In accomplishing the pulsatile studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. GnRH and hCG challenge tests were done on one or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH, LH, testosterone, dihydrotestosterone and delta 4-androstenedione by established RIAs and an in vitro bioassay for LH. During the frequent sampling period of 24-h duration for all except postnatal animals, testosterone pulses of large amplitude (up to 8-fold) occurred in postnatal, pubertal, and adult animals. Pulsatile gonadotropin secretion was seen at all ages; however, the highest pulses (up to 15-fold) occurred in prepubertal animals even though this was an infrequent occurrence. Time series analysis techniques were applied for objective statistical characterization of cyclic patterns. Basic rhythms corresponding to 50- to 90-min frequency cycles in gonadotropin secretion were identified. Substantive differences between LH concentrations by bioassay and RIA were seen infrequently. Our findings illustrate that: 1) circulating gonadotropin and testosterone pulses change in amplitude but not necessarily frequency during pubertal development, and 2) primate models are a useful paradym for the longitudinal study of human male sexual development. We conclude that where direct human investigation may be limited, much can be learned by study of these primate surrogates.

Male sexual development in the monkey. II. Cross-sectional analysis of pulsatile hypothalamic-pituitary secretion in castrated males

Pulsatile secretion of serum gonadotropins was studied in 16 castrated monkeys from 4 weeks of age through adult life. Animals were castrated at various ages from birth through adult life. Although some studies of the gonadotropin-secretory patterns were longitudinal in nature, most comparisons were cross-sectional. On the basis of our observations, we have arbitrarily grouped the animals into 4 developmental ages: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In carrying out these studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling catheter. GnRH challenge tests were done on 1 or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH and LH by established RIAs and an in vitro bioassay for LH. During the frequent sampling period (24 h for all except postnatal animals), the amplitude of gonadotropin pulses was greatest in adult animals followed by postnatal and pubertal monkeys. During pubertal development, there was a marked increase in the magnitude of gonadotropin pulses, and remarkedly, there was a substantial increase in the LH bioassay: RIA (greater than 5:1) by adult life. GnRH challenge tests of gonadotropins correlated with these observations. Time series analysis was applied to the data for objective statistical characterization of cyclic patterns. Our findings can be summarized: 1) during pubertal maturation there is a change in amplitude but not frequency of gonadotropin pulses, 2) pubertal development of the hypothalamic-pituitary axis advances in the absence of gonadal feedback, and 3) there is a significant increase in the LH bioassay: RIA during pubertal development. We conclude that the castrate monkey is a valuable adjunct to direct clinical investigations of the mechanisms controlling human sexual development.

Effect of GnRH antagonist, [Ac-delta 3Pro1, pFDPhe2, DTrp3,6] GnRH, on pulsatile gonadotrop in secretion in the castrate male primate

Three different doses of a potent antagonist to GnRH, [Ac-delta 3Pro1, pFDPhe2, DTrp3,6], GnRH were compared in adult male monkeys to determine the acute effect on pulsatile gonadotropin secretion. In accomplishing these studies, blood was drawn at 15 min intervals over 24-30 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. After a 3 to 6 h control period, 2.0, 0.2 or 0.02 mg GnRH antagonist/kg bw in 1 ml corn oil sc, was given to castrate adult monkeys. The highest dose decreased circulating LH (by radioimmunoassay and bioassay) and FSH whereas the intermediate dose decreased LH only. The higher dose produced both a more prolonged and greater reduction in circulating gonadotropins. These data demonstrate that this GnRH antagonist can reduce serum gonadotropins both acutely and for intervals greater than 24 h.

Quantification of gray/white matter in neonates and adults

Quantitation of gray/white matter is important in evaluation of cerebral blood flow, atrophy, and development of the brain. First-order statistical analysis of neonatal computed tomographic (CT) images revealed that there was only a 6 Hounsfield unit (H) difference between gray and white matter compared with the observed 3 H for the standard deviation over the field of a skull water phantom. Scene segmentation methods based on first-order statistics proved unsuccessful in separating gray and white matter. A new regional clustering algorithm based on local textural properties was developed for separation of these structures.

Thoracic duct lymph flow after pancreatitis: role in circulatory collapse

We examined the effects of acute hemorrhagic pancreatitis on thoracic duct lymph flow and its protein concentration. Thoracic duct lymph flow increased and the protein concentration decreased. These changes in the lymph were associated with steady decreases in arterial pressure and cardiac output and increase in systemic vascular resistance. The results suggest that the increased lymph flow and decreased protein concentration were due to either an ultrafiltration causing a dilution of the lymph protein concentration or to the heterogeneous origin of thoracic duct lymph such that redistribution of blood flow to the essential beds (eg, kidneys) after arterial hypotension altered the lymph flow and its protein concentration. The increase in filtration and the absence of a compensatory "autotransfusion" during arterial hypotension may be a mechanism contributing to circulatory shock in acute pancreatitis.

Differential patency and limb salvage for polytetrafluoroethylene and autogenous saphenous vein in severe lower extremity ischemia

Polytetrafluoroethylene (PTFE) was compared to autogenous saphenous vein (ASV) in 133 femoropopliteal and femorotibial or peroneal bypass procedures performed in limb salvage during a 4-year period. PTFE was used as an alternative prosthesis in the absence of a suitable ASV. Sixty-nine femoropopliteal bypasses (FPBPs) were studied--36 with ASV and 33 with PTFE. Sixty-four femorotibial or peroneal bypasses were categorized as femoral distal bypasses (FDBPs)--34 with ASV and 30 with PTFE. With a 3-year clinical follow-up, cumulative function rate (CFR)--patency including thrombectomy--for FPBP with ASV was 65% as compared to 53% for PTFE (P greater than 0.05), whereas the limb salvage rate (LSR) was 75% with ASV and 56% for PTFE (P greater than 0.05). However for FDBP, the GFR was 55% for ASV and 7% for PTFE, whereas the LSR was 55% with ASV and 26% for PTFE. The cumulative patency rate (CPR)--initial thrombosis of a prosthesis as an endpoint--was not significantly (P greater than 0.05) different from CFR, suggesting that thrombectomy with or without distal anastamotic revision does not contribute to patency of the PTFE prosthesis in these limb salvage cases. PTFE was a suitable alternative to ASV for FPBP; however, PTFE is recommended for FDBP in selected cases only.

Plain and metrizamide CT of lumbar disk disease: comparison with myelography

Computed tomography with and without administration of intrathecal contrast material was evaluated in 100 patients with suspected lumbar disk disease. Metrizamide computed tomography was performed in 75 patients and plain computed tomography was performed in 25. Metrizamide computed tomography was more accurate than plain computed tomography. It also disclosed many lesions not shown by metrizamide myelography at the lumbosacral level. Very few lesions were revealed by myelography that were not seen by metrizamide computed tomography. The small amount of intrathecal metrizamide needed for scanning has practically no side effects. Experience in 12 patients indicates that the procedure may be performed safely on an outpatient basis. This study suggests that computed tomography should be given serious consideration as the primary definitive radiographic examination of suspected lumbar disk disease.

Effect of acute pancreatitis on pulmonary transvascular fluid and protein exchange

We used the anesthetized sheep lung lymph preparation to examine the effects of acute hemorrhagic pancreatitis on pulmonary transvascular fluid and protein exchange. Induction of acute pancreatitis by injection of trypsin and sodium taurocholate into the pancreatic duct caused significant increases (p less than 0.05) in lung lymph flow, ratio of lymph to plasma protein concentration (L/P ratio), and transvascular protein clearance. Pulmonary arterial and pulmonary arterial wedge pressures did not change significantly, but pulmonary blood flow decreased (p less than 0.05) and pulmonary vascular resistance increased (p less than 0.05). In contrast to the effects of acute pancreatitis, left atrial hypertension caused increases in lung lymph flow that were associated with decreases in the L/P ratio. Extravascular lung water content was increased after acute pancreatitis by 25% from the value obtained in sham-operated animals in which saline was injected into the pancreatic duct. These findings indicate that acute hemorrhagic pancreatitis causes an increase in pulmonary vascular permeability to proteins. Because pulmonary vascular pressures did not change, the increased permeability may be due to the cellular and humoral factors rather than hemodynamic mechanisms.

Subacute reactions to intrathecal amipaque (metrizamide), conray and dimer X: a structural and ultrastructural study

Adult New Zealand rabbits were injected intrathecally with 200 or 300 mgI/ml of metrizamide, meglumine iocarmate or meglumine iothalamate. They were placed in the Trendelenburg position for 20 min and allowed to survive for 1, 2 or 3 weeks. Sacrifice was by intraarterial perfusion of aldehydes under anesthesia followed by preparation of brain and major venous sinuses for light and electron microscopy. Major findings were subpial edema and inflammatory reaction of superficial brain, leptomeninges, subarachnoid space and arachnoid granulations. They were most severe after iothalamate and milder after metrizamide. The severity decreased with time. It is of significance that severe reactions occurred after 300 mgI/ml concentration of metrizamide.

Pulmonary transvascular fluid dynamics in sheep during hemorrhage

The effects of hemorrhage on pulmonary hemodynamics and lung transvascular fluid dynamics were studied in sheep. We found that 2 hr of hemorrhage caused a fall in lung lymph flow (p less than 0.05) and no significant change in lymph protein concentration. The fall in lymph flow was not due to decreased vascular surface area since the regional distribution of pulmonary perfusion was not altered during hemorrhage; however, the decrease in lymph flow was associated with decrease (p less than 0.05) in the calculated pulmonary microvascular pressure. The extravascular lung water lung content per g bloodless dry lung was increased (p less than 0.05) in the hemorrhaged sheep from the control values. Pulmonary edema was not due to increased lung vascular endothelial permeability since the net transvascular protein flux was not increased. The finding that pulmonary edema occurred despite the consistent decreases in lymph flow suggests that edema may be due to hemorrhage-induced lymphatic "failure" or that edema fluid is sequestered in spaces (e.g., endothelial cells) where if cannot be drained by the lymphatics.

Site of pulmonary edema after unilateral microembolization

The effect of unilateral pulmonary microembolization on regional lung extravascular fluid accumulation was determined in dogs. Embolization was produced by injecting 100-micrometer-diam glass beads (0.25 g/kg) into the right pulmonary artery. After embolization of one lung, pulmonary arterial pressure (Ppa) and pulmonary vascular resistance increased (P less than 0.05) from base-line values of 11.7 +/- 1.3 to 17.9 +/- 1.3 Torr and of 3.4 +/- 0.5 to 5.5 +/- 0.5 Torr/(1/min). Blood flow to embolized lung measured with labeled microspheres decreased from 104.2 +/- 24.9 to 35.2 +/- 9.2 ml/min.g bloodless lung after embolization, whereas flow to the normal lung increased from 43.1 +/- 5.6 to 71.2 +/- 19.2 ml/min.g bloodless lung. Extravascular lung water-to-bloodless dry lung weight ratio (W/D) of 4.97 +/- 0.32 was greater (P less than 0.001) in the embolized lung than the value of 3.34 +/- 0.15 in nonembolized lung. In six dogs pretreated with 500 U/kg of heparin, a similar degree of duration of embolization and similar hemodynamic changes did not result in significant differences in W/D (3.88 +/- 0.18 in right lung vs. 3.02 +/- 0.53 in the left lung), and the right lung ratio was less (P less than 0.05) than the value in the heparinized dogs, suggesting that humoral mechanisms contribute to the genesis of pulmonary edema after regional embolization. Therefore, unilateral embolization leads to a greater increase in extravascular content in the embolized lung than in the nonembolized lung. Because Ppa was in the normal range after embolization, regional pulmonary edema may be due partly to the local release of factors that increase lung vascular permeability.

Neonatal intraventricular hemorrhage: a serial computed tomography study

Thirty infants weighing less than 1,500 g at birth and requiring assisted ventilation were studied by computed tomography (CT) as soon as possible after birth and at intervals thereafter. Hemorrhage were frequently detected within the first 48 hr of birth. Two infants had normal scans initially but developed intraventricular hemorrhage later. One infant had subependymal hemorrhage that later ruptured into the ventricles. Six deaths were due directly to intracranial hemorrhages. Hydrocephalus developed in seven and atrophy in two survivors. There was poor correlation between CT scan and clinical evidence of intracranial hemorrhage.

Passage of Amipaque (metrizamide) through the arachnoid granulations

125I labelled Amipaque (metrizamide) was introduced by cisternal puncture into six rabbits and perfused at various pressures. The torcular was exposed, frozen rapidly, and excised intact. Sections of arachnoid proliferations were made from the frozen specimen and either freeze dried or sandwiched directly for autoradiography. Some specimens were freeze dried en bloc prior to sectioning and sandwiching. All sections were exposed for 2-3 weeks at -80 degrees C prior to development of the autoradiographs. On microscopic examinations of the autoradiographs most of the activity was in the tubules or between cells suggesting intercellular passage. Some label was also present within the brain. The significance of this is discussed.

Intracranial cysts

While CT scanning is useful for diagnosis of hydrocephalus and fluid-containing intracranial cysts, air studies are often necessary to determine whether the cysts communicate with the ventricular or subarachnoid space. When obstructive hydrocephalus results, decompression of the cyst is normally adequate. Hydrocephalus not caused by a cyst still requires decompression, but in addition the cyst has to be treated. Until the exact pathways of absorption of water-soluble contrast media such as metrizamide are fully understood, it may be advisable not to administer them into the ventricles in patients with obstructive hydrocephalus. A combination of CT and air studies may offer information not obtainable with either modality alone.

Ventricular opacification after intravascular injections of contrast material

The cerebral ventricles of two neonates were demonstrated on CT scans and plain radiographs after the intra-arterial injection of contrast material. Leakage of contrast material into the ventricles after intravenous injection probably indicates damage of the blood-brain barrier. Breakdown of this barrier results only from severe and prolonged anoxia because cerebral vessels are much more resistant to anoxia than neuronal tissues. The authors have not observed ventricular opacification in adults.

Computed tomography of the spine and spinal cord

Configurations of 50 normal lumbar canals at each vertebral level were assessed and the dimensions of the canal at these levels measured. The appearances of the contents of the canal and their absorption values were carefully analyzed in the lumbar, cervical, and thoracic regions. Of 75 scans of patients with specific spinal symptoms, 38 showed abnormalities representing 19 pathological entities. The appearances of these lesions on scans are compared with normal scans, and the usefulness of CT scans in assessing lesions of the bone and within the canal is discussed.

Tuberous sclerosis. Comparison of computed tomography and conventional neuroradiology

Sixty-two patients with tuberous sclerosis were studied by skull radiography. In addition, 16 had CT scanning, 26 had air studies, and 5 had cerebral angiography. Both subependymal and parenchymal tubers were shown on CT; all had a higher density than the brain and none were enhanced by contrast material. CT showed tubers in 13 of 16 patients, including 4 of 6 patients with glioma and hydrocephalus. Air studies showed subependymal tubers in 12 of 26 patients. Four other patients had intraventricular gliomas but no tubers. Skull radiographs showed spotty calcification, compatible with tuberous sclerosis, in 30 cases. Four patients had calcification compatible with tumor. Angiograms were nonspecific, showing intraventricular masses but no tubers.

Flexible fiberoptic bronchoscopy and endobronchial tamponade in the management of massive hemoptysis

Flexible fiberoptic bronchoscopic examination with systematic bronchial lavage was performed in ten patients with massive hemoptysis. Localization of the bleeding to the distal segments of the bronchial tree and endobronchial balloon tamponade were achieved in all cases. The technique is rapid, simple, and effective in controlling life-threatening hemoptysis in patients who are unsuitable for resection due to inadequate pulmonary reserve or other causes.

Computerized tomography and angiography in subarachnoid haemorrhage

Our study of 100 multiple aneurysm cases show that 66 survivied the initial danger period either with surgery, or by conservative treatment. Of these only one may have died subsequently from bleeding from an incidental aneurysm, during a continuing follow-up period now averaging more than seven years. In a separate series of 75 patients presenting clinically with subarachnoid haemorrhage it was possible to lateralize or approximately localize the site of bleeding by CAT in 56; 31 were from aneurysms and 13 from arteriovenous malformations. In the remaining 19 cases CAT was unhelpful in indicating the site of haemorrhage; 12 had aneurysms; no cause was found in the remainder. CAT was more valuable in localization in the seven days following the haemorrhage (86 per cent) than later (34 per cent). The low risk of bleeding from incidental aneurysms makes us feel that treatment confined to the lesion which is responsible for the subarachnoid haemorrhage is not an unreasonable policy in the large majority of these patients. Detailed angiographic study of the site of haemorrhage is performed, but once this has been achieved, more extensive angiography is not routine, but is determined by the requirements of the surgery directed at the site of haemorrhage.

Intercostal pulmonary hernia

In five cases of intercostal pulmonary hernia, the hernia occurred following blunt chest trauma in two cases, after tube thoracostomy drainage in two, and following rib resection in one. Surgical repair was accomplished in three cases with good results, while in the remaining two the hernia underwent spontaneous regression.