Two magneto-encephalographic epileptic foci did not coincide with the electrocorticographic ictal onset zone in a patient with temporal lobe epilepsy

To evaluate the usefulness and limitations of magneto-encephalography (MEG) for epilepsy surgery, we compared 'interictal' epileptic spike fields on MEG with ictal electrocorticography (ECoG) using invasive chronic subdural electrodes in a patient with intractable medial temporal lobe epilepsy (MTLE) associated with vitamin K deficiency intracerebral hemorrhage. A 19-year-old male with an 8-year history of refractory complex partial seizures, secondarily generalized, and right hemispheric atrophy and porencephaly in the right frontal lobe on MRI, was studied with MEG to define the interictal paroxysmal sources based on the single-dipole model. This was followed by invasive ECoG monitoring to delineate the epileptogenic zone. MEG demonstrated two paroxysmal foci, one each on the right lateral temporal and frontal lobes. Ictal ECoG recordings revealed an ictal onset zone on the right medial temporal lobe, which was different from that defined by MEG. Anterior temporal lobectomy with hippocampectomy was performed and the patient has been seizure free for two years. Our results indicate that interictal MEG does not always define the epileptogenic zone in patients with MTLE.

Effects of sevoflurane and isoflurane on electrocorticographic activities in patients with temporal lobe epilepsy

To compare the neuroexcitatory effects of sevoflurane and isoflurane, we recorded electrocorticograms (ECoG) during wakefulness and during sevoflurane and isoflurane anesthesia in six patients with temporal lobe epilepsy (TLE). These patients had subdural grid electrodes chronically implanted in the temporal region. During sevoflurane anesthesia at 1.5 minimum alveolar concentration (MAC) of the combination with 67% nitrous oxide (N2O), a marked increase in interictal paroxysmal activities was observed in four patients. Two patients had a slight increase in paroxysmal activities. Activated areas were widely distributed, not being confined to the ictal onset zone of spontaneous seizures. However, isoflurane anesthesia at 1.5 MAC of the combination with 67% N2O was associated with less increased paroxysmal activity. While the neuroexcitatory properties of sevoflurane proved greater than those of isoflurane, the widespread irritative response to sevoflurane administration was not helpful in localizing the epileptogenic area.

Phantom studies for estimation of defect size on cardiac (18)F SPECT and PET: implications for myocardial viability assessment

SPECT with (18)F-FDG has emerged as an alternative to dedicated PET for the assessment of myocardial viability. However, whether FDG SPECT can reliably quantify the extent of viable and scarred myocardium is uncertain. The aim of this study was to investigate whether SPECT with an (18)F-labeled agent would provide information on defect size similar to that provided by dedicated PET.

METHODS

Imaging was performed using an elliptic cylinder chest phantom with simulated bone, lung, mediastinum, liver, and heart. (18)F was administered into the myocardium, mediastinum, right and left ventricular cavities, and liver. Plastic inserts (n = 11) ranging in size from 2% to 60% of the myocardium were used to simulate transmural myocardial infarctions. The chest phantom was imaged with a dedicated PET camera and with a double-head SPECT camera equipped with ultra-high-energy collimators. Both SPECT and PET data were analyzed using a semiquantitative polar map approach. Defects were quantified using various cutoff thresholds ranging from 30% to 80% of peak activity and were expressed as a percentage of the left ventricular myocardium. Defect size as measured by SPECT or PET was compared with true defect size.

RESULTS

The measured SPECT defect size was highly variable depending on the cutoff used, whereas PET defect size was relatively constant over the range of cutoffs tested. The mean absolute difference between measured and true defect sizes was minimal at a cutoff of 50% of peak activity for both SPECT (3.3% +/- 3.3%) and PET (2.7% +/- 2.5%). For this threshold, both SPECT and PET measurements showed an excellent correlation with true defect size (r = 0.98 for SPECT and 0.99 for PET). The correlation between SPECT and PET measurements was also excellent (r = 0.99; P < 0.01).

CONCLUSION

If an appropriate threshold is used to define a defect, SPECT with an (18)F-labeled agent can accurately measure defect size similarly to the manner of PET.

[An operated case of medial temporal lobe epilepsy associated with schizencephaly]

A 24-year-old male of medial temporal lobe epilepsy associated with schizencephaly was presented. He developed complex partial seizure after head trauma at the age of a year and 7 months, which became intractable at the age of 13 year. MRI demonstrated a schizencephalic cleft in the right peri-Rolandic area, cortical dysplasia in the right medical parietal and occipital lobes, and right hippocampal atrophy. Scalp-recorded EEG failed to localize the ictal onset zone. Interictal FDG-PET and ECD-SPECT indicated hypometabolism and hypoperfusion of the right entire temporal lobe, and ictal ECD-SPECT increased perfusion of this area. Chronic subdural electrode recording clearly demonstrated that ictal onset zone was located not on the schizencephalic cleft or its surrounding cortex but on the right medial temporal lobe. Following right anterior temporal lobectomy with hipppocampectomy, seizure control became easy. For the identification of the epileptogenic zone in patients with schizencephaly, chronic subdural electrode recording is mandatory.

Neuromagnetic assessment of epileptogenicity in cerebral arteriovenous malformation

Magnetoencephalographic (MEG) activities were recorded in five patients with cerebral arteriovenous malformation (AVM) who presented with epilepsy and no clinical history of intracranial hemorrhage, using a 37-channel DC superconducting quantum interference device (SQUID) system. While scalp-recorded electroencephalograms (EEG) failed to reveal paroxysmal discharge, MEGs demonstrated localized high frequency magnetic activity (HFMA). Magnetic source imaging (MSI) depicted the accumulation of equivalent current dipole (ECD) originating from HFMA around the nidus, and the ECD localization agreed well with spike localization on intraoperative electrocorticography (ECoG). These areas corresponded with the areas of hypoperfusion on single photon emission tomography and the intraoperative laser Doppler flow meter. We discussed the application of MEG in estimating interictal paroxysmal activity sources in patients with AVM and addressed the questions of its reliability and validity in source localization.

[Transurethral microwave thermotherapy for benign prostatic hyperplasia]

The clinical efficacy of transurethral microwave thermotherapy using the PROSTCARE apparatus was evaluated in 60 patients with bladder outlet obstruction associated with benign prostatic hyperplasia. All of the 60 patients received a single thermal session for 60 minutes with an average intraprostatic temperature of 45 degrees C. They were evaluated by analyzing the international prostate symptom score (IPSS), quality of life (QOL) index, maximum urinary flow rate and prostate volume at 2 months after the treatment to estimate criteria for efficacy of treatment in BPH. Both IPSS and QOL index improved significantly. The maximum urinary flow rate improved but there was no significant change. There was no significant change in prostate volume. The rates of improvement in IPSS, QOL index and maximum flow rate were 73%, 78% and 47% of the patients respectively. The rate of overall improvement was 78% of the patients. As a complication after the treatment, 2 patients complained of ejaculation disturbance.

Temporal lobe epilepsy: a clinicopathological study with special reference to temporal neocortical changes

The number of patients undergoing surgical treatment for pharmacoresistant temporal lobe epilepsy is rapidly increasing. While there have been many clinicopathological studies concerning the medial structures of the temporal lobe in temporal lobe epilepsy, its lateral structures have received little attention. To examine the nature and frequency of lateral temporal lobe abnormalities that occur in temporal lobe epilepsy, 22 patients who underwent standard anterior temporal lobectomy with hippocampectomy for intractable temporal lobe epilepsy were studied. The mean ages at the onset of seizure and at surgery were 15.9 years and 27.7 years, respectively. The electroclinically determined epileptogenic zones were the medial structures of the temporal lobe in 16 patients and the lateral in six. There was histologic evidence of hippocampal sclerosis in 12 of the 16 patients with medial onset seizures and in three of the six patients with lateral onset seizures. The lateral structures of the temporal lobe showed variable degrees of histological abnormalities in 21 patients. Among these abnormalities, heterotopic white matter neurons were observed in six of the 16 medial patients and in all the lateral patients. Glial changes were also common abnormalities, and often glial fibrillary acidic protein (GFAP)-positive astrocytes were present over the entire temporal lobe. In addition to hippocampal sclerosis, cerebral microdysgenesis and gliosis in the lateral structures of the temporal lobe may have a significant role in epileptogenesis of temporal lobe epilepsy.

[Occipital encephalocele and epilepsy]

We report the incidence of epilepsy in 7 patients with occipital encephalocele (meningocele: 6 cases, meningoencephalocystocele: 1 case). Two cases had epilepsy and a case without the history of epileptic seizure had an epileptic pattern on the EEG. All these 3 cases had cortical dysplasia(CD) such as schizencephaly and subcortical gray matter, and two of them were associated with mental retardation. The location of the prominent CD was correlated with the EEG abnormalities and clinical epileptic pattern in each case. Associated hydrocephalus and placement of VP shunt had no significant influence on the occurrence of the epilepsy. Thus, complicated CD is thought to be epileptogenic in patients with occipital encephalocele.

[Surgical treatment for temporal lobe epilepsy in childhood]

We retrospectively analyzed 5 children (11-15 year) with intractable temporal lobe epilepsy (TLE) who underwent the anterior temporal lobectomy with hippocampectomy. Cases 1-3 had medial TLE (MTLE) with histologically verified hippocampal sclerosis, Case 4 had lateral TLE, and Case 5 had MTLE with old hemorrhagic lesion in the lateral temporal lobe. In Cases 3-5, chronic invasive electrocorticography recording using subdural electrodes was obtained, while in Cases 1 and 2, the epileptogenic region was defined by noninvasive preoperative evaluation. Postoperatively, Cases 1-3 became seizure free. All patients had psychosocial problems after the onset of their epilepsy, which was not improved even after the surgical control of epilepsy. Since most patients had morphological change and perfusional and metabolic disturbance outside the hippocampus at the time of surgery, earlier surgical consideration may be necessary.

Magnetoencephalographic analysis of periodic lateralized epileptiform discharges (PLEDs)

OBJECTIVE

To clarify the spatial and temporal distribution of the electroencephalographic (EEG) pattern termed 'periodic lateralized epileptiform discharges' (PLEDs), we performed magnetoencephalography (MEG) to analyze PLEDs in a patient with a right parietal metastasis associated with meningeal carcinomatosis.

METHODS

A 37-channel biomagnetometer was used to simultaneously record the EEG and MEG. Equivalent current dipole (ECD) source localization was calculated based on a single-dipole model and mapped onto a magnetic resonance image. Single-photon emission computed tomography with technetium-99-hexamethyl-propyleneamine oxime (HMPAO-SPECT study) was also performed during both presence and absence of PLEDs according to an EEG monitor.

RESULTS

By EEG the PLEDs, predominantly right-sided, consisted of a typical negative triphasic spike followed by a slow negative wave. By MEG the PLEDs had a sequence with 3 distinct components. ECDs in the 3 components were localized to the cortex around the lesion, although exact localization and dipole direction varied between components. HMPAO-SPECT demonstrated hypoperfusion of the lesion and adjacent cortex during both quiescence and appearance of PLEDs.

CONCLUSION

Our results indicate that PLEDs originated from the hypoperfused cortex surrounding the lesion.

[Schizencephaly: clinical and MRI features]

We report the clinical and neuroimaging features of 4 cases with schizencephaly. Case 1 had bilateral schizencephaly with open-lip on the right and closed-lip on the left. Case 2 had unilateral schizencephaly with closed-lip on the left and subcortical heterotopia on the right. Case 3 had unilateral schizencephaly with closed-lip on the left. Case 4 had bilateral closed-lip schizencephaly. Although all cases except for Case 3 had bilateral lesions, neurodevelopmental outcome was generally good; Case 1 and 3 had mild hemiparesis. All patient have epilepsy which are well-controlled with antiepileptic drugs. Thus, the clinical presentation of schizencephaly, even if bilateral lesions, are quite variable.

Distribution of brainstem somatosensory evoked potentials following upper and lower limb stimulation

OBJECTIVE

Because somatosensory evoked potentials (SEP) to lower limb stimulation have not been recorded from the brainstem to the extent that upper limb SEPs have been studied, we compared brainstem recordings in response to both median nerve (MN) and posterior tibial nerve (PTN)stimulation.

METHODS

SEPs were recorded directly from the dorsal surface of the brainstem in four patients with fourth ventricle tumors.

RESULTS

Following MN stimulation, medullary SEPs were characterized by a major negativity (N1) preceded by a small positivity (P1) and followed by a large positivity (P2). In the pons, triphasic waves with predominant negativity were obtained. With PTN stimulation, similar medullary SEPs with a P1'-N1'-P2' configuration and pontine SEPs with a triphasic waveform were obtained.

CONCLUSIONS

Since the distribution of PTN SEP was identical to that of MN SEP, PTN SEPs are thought to be generated by mechanisms similar to those for MN SEP. Thus, the P1' and N1' of medullary SEP would be generated by the dorsal column fibers that terminate in the nucleus, with P2' possibly arising postsynaptically in the nucleus. The triphasic PTN SEP from the pons reflects an axonal potential generated in the medial lemniscal pathway.

[Temporal lobe epilepsy associated with old intracerebral hemorrhage due to capillary telangiectasis in the temporal lobe: case report]

A case of 45-year-old female, who presented with temporal lobe epilepsy was reported. The patient was found to have old intracerebral hemorrhage due to capillary telangiectasis in the temporal lobe. On the intraoperative electrocorticography, frequent paroxysmal activities were recorded independently both on the medial and lateral aspects of the temporal lobe. Even after resection of the lateral temporal lobe, frequent paroxysmal discharges were noted on the hippocampus. Histologically, there are astrogliosis and hemosiderin deposits in the white matter around the telangiectasis and the old hematoma. It is postulated that the hippocampus gained secondary epileptogenicity.

Immunohistochemical expression of trk receptor proteins in focal cortical dysplasia with intractable epilepsy

Focal cortical dysplasia (FCD), which is often associated with intractable epilepsy, is a form of abnormal structure of the cerebral cortex caused by a disorder of normal neocortical development. In such cerebral lesions obtained from four patients (two male, two female; average age 32.3 years at operation), the immunohistochemical expression of Trk receptors, which interact with neurotrophins and result in both growth and maturational changes in neuronal cells, was investigated in relation to the possible histogenesis of these lesions. In all cases, a derangement of the cortical laminar structure, dysplastic cytomegalic neurones, and large round balloon cells were the characteristic histological features. Immunohistochemically, the TrkA expression was localized in large dysplastic cytomegalic neurones, and TrkB expression was observed in large dysplastic and relatively small neuronal cells within the affected cortex. Although the exact roles of neurotrophins and their receptors in the pathogenesis of FCD remain uncertain, its development might be governed by such neurotrophic influences, and thus possibly prevent the death of abnormal neuronal cells. In addition, Trk receptors in FCDs may also play a role in establishing in the intrinsic epileptogenicity of FCDs.

Relationship between the biodistributions of radioactive metal nuclides in tumor tissue and the physicochemical properties of these metal ions

This study was undertaken to elucidate the relationship between the biodistribution of radioactive metal nuclides in tumor tissue and its physicochemical properties. Potassium analogs (86Rb, 134Cs, 201Tl) were taken up into viable tumor tissue, although 22Na concentrated in necrotic tumor tissue. 67Ga and 111In were more predominant in inflammatory tissue than in the viable and necrotic tumor tissue. 169Yb and 167Tm accumulated in viable tumor tissue and tissue containing viable and necrotic tumor tissue. 67Ga, 111In, 169Yb and 167Tm were bound to the acid mucopolysaccharide with a mol. wt. of about 10,000 daltons in the tumor tissue. 46Sc, 51Cr, 95Zr, 181Hf, 95Nb, 182Ta, and 103Ru were highly concentrated in inflammatory tissue and were bound to the acid mucopolysaccharides with a mol. wt. exceeding 40,000 daltons. 65Zn and 103Pd concentrated in viable tumor tissue and were bound to the protein in the tissue. The results suggest that the difference in intra-tumor distribution of these elements is caused by a difference in the binding substances (or status) of these elements in the tissues, and the binding substance is determined by physicochemical properties of the elements. We therefore conclude that the biodistribution of radioactive metal ions in tumor tissue is determined by its own physicochemical properties.

Intrinsic epileptogenicity of focal cortical dysplasia as revealed by magnetoencephalography and electrocorticography

Focal cortical dysplasia (FCD) is often associated with severe partial epilepsy. In this study, we performed magnetoencephalography (MEG) and electrocorticogrsphy (ECoG) on four patients with FCD-associated epilepsy to confirm the 'intrinsic' epileptogenicity of FCD. In all patients, we determined the three-dimensional locations of the magnetic sources of the interictal paroxysmal activities by a single dipole model, and then the estimated dipole localization was superimposed on the magnetic resonance image. The dipole clusters were located in the T2-prolonged lesions, namely in the FCD lesions themselves. All patients underwent surgery for their medically intractable epilepsy, and the acute and/or chronic ECoG were thereafter recorded. Either frequent or continuous paroxysmal activities were recorded from the ECoG electrodes which were placed over the surface of the FCD lesion, while few paroxysmal activities were observed on the normal appearing adjacent cortex. Intraoperative depth recordings were performed in a patient with the needle electrode inserted into the FCD lesion and they revealed these paroxysmal foci to be located not on the cortical surface but at a depth of 15 mm from the cortical surface where both abnormal giant neurons and bizarre large eosinophilic cells (so-called balloon cells) were also prominently observed on the postoperative histological sections. Following a lesionectomy combined with the removal of the underlying white matter, three patients demonstrated a favorable seizure outcome. Our findings thus suggest the FCD lesions to be highly and intrinsically epileptogenic lesions.

[Clinical experience of image-guided neurosurgery with a frameless navigation system (StealthStation)]

We have applied the frameless navigation system (StealthStation) to various neurosurgical procedures to examine its usefulness. The system consists of a UNIX based workstation that creates triplanar and 3-dimensional images; an infrared optical digitizer with camera array; a reference-light-emitting diode (LED) array (e.g., reference array); and pointer probe modified by the addition of LEDs. This system was used to assist in placing a minimal skin incision and craniotomy in 4 cases, to determine the tumor/brain interface in 2 cases, to target the subcortical lesion in one case, and to correlate bony structure with a skull base tumor in 3 cases. The combined use with magnetic source imaging of the somatosensory cortex allowed a fast orientation of eloquent areas in 2 cases with peri-Rolandic tumor. This system, thus, was proved to be a useful adjunct to open-tumor biopsy or resection.

[Carbamazepine induced hyponatremia]

Carbamazepine (CBZ) is a drug which can induce the syndrome of inappropriate antidiuretic hormone (SIADH). Until 1980's, there were reports regarding CBZ-induced SIADH, but it is rarely reported these days. We here report two cases of CBZ-induced SIADH. Hyponatremia in these cases was rapidly improved by withdrawal of administration of CBZ. According to the previous reports, the rate of hyponatremia in patients receiving CBZ is not small. It ranges from 48% to 31%. As CBZ is frequently used for patients with epilepsy and neuralgia, not only their blood CBZ concentration but also their serum Na level should be monitored.

[Two cases of mesial temporal lobe epilepsy associated with old intracerebral hemorrhage in the lateral temporal lobe without "dual pathology"]

Two cases of intractable temporal lobe epilepsy associated with old intracerebral hemorrhage in the lateral temporal lobe were reported. Although preoperative magnetic resonance imaging (MRI) failed to reveal hippocampal atrophy with T2 hyperintensity, electrocorticographic (ECoG) recording with chronic invasive subdural electrodes indicated the mesial temporal lobe to be an ictal onset zone. After anterior temporal lobectomy involving the lesion and hippocampectomy, the patients became seizure-free. Hippocampal sclerosis, namely "dual pathology", was not noted on histological examination. Careful ECoG recording with chronic subdural electrodes is mandatory even when the preoperative MRI does not demonstrate the radiological hippocampal sclerosis.

[Efficacy of the fluid attenuated inversion recovery (FLAIR) sequence of MRI as a preoperative diagnosis of hippocampal sclerosis]

A newly advanced MRI pulse sequence, the FLAIR (fluid attenuated inversion recovery) imaging, in which a long TE spin echo sequence is used with suppression of the CSF with an inversion pulse, displays the CSF space as a no-signal intensity area. There have been only a few reports on the FLAIR pulse sequence of temporal lobe epilepsy (TLE) as yet. We examined 9 cases of intractable TLE by FLAIR images and analyzed the advantages and disadvantages of the FLAIR pulse sequence for decision making on temporal lobectomy. All patients underwent anterior temporal lobectomy with hippocampectomy, and the diagnoses were confirmed histologically after surgery. Abnormally high T2 signals (HT2S) were more conspicuous with the FLAIR sequence than with any of the conventional sequences. Tilted axial plane, orientated along to the long axis of the hippocampal body, clearly demonstrated hippocampal atrophy (HA). Selection of a FLAIR sequence into the routine MR examination of patients with TLE is recommended.

[Dual isotope SPECT with 99mTc and 123I using four-energy-window (FEW) method]

We devised "four-energy-window" (FEW) method which permits simultaneous acquisition for dual isotope single photon emission tomography (SPECT) studies using 99mTc and 123I of which photopeak is in close vicinity to each other. This acquisition method requires a total of four energy windows: two main windows for 99mTc (126-143 keV) and 123I (156-175 keV), respectively, and two 5% sub-windows which are set below the 99mTc window and above the 123I window, respectively. Two virtual windows (5%) are additionally set above the 99mTc and below the 123I window, respectively, to apply the triple-energy-window (TEW) method for the scatter correction. A phantom study demonstrated that photocounts from the two radionuclides could be completely separated from each other and that SPECT images obtained had preferable property for quantitative analysis. This method was applied to clinical, dual-radionuclide myocardial studies using 99mTc-MIBI and 123I-BMIPP, and was found to provide excellent images each tracer.

[Effectiveness of the radioactive strontium (89Sr) chloride agent, SMS.2P for pain palliation in patients with metastatic bone tumor in phase III multicenter clinical trial]

The phase III clinical trial of strontium-89 chloride agent (SMS.2P) was performed in 90 patients with painful bone metastases secondary to prostate (53), breast (18) and other types of cancer (19). Some patients experienced a transient increase in pain or nausea and vomiting. However both symptoms subsided and serious side effects were not observed in any of the patients. As reported, we confirmed some abnormal changes in peripheral blood picture. A decrease in the number of white blood cells and platelets was considered to be partly a result of bone marrow suppression due to 89Sr irradiation. Pain was substantially improved after 89Sr therapy in 58% of the patients and there was some alleviation in 12%. The release from pain was accompanied by an improved quality of life for these patients including sleep patterns and morbidity. Some patients were able to resume their former life styles. Most of the improved patients experienced pain relief from days to one week following 89Sr therapy and in half cases, this remained effective for 2 or 3 months. There were even cases in which the pain relief continued over an observation period of time of clinical study.

Hyperperfusion and hypermetabolism in brain radiation necrosis with epileptic activity

We report a case of high uptake of 11C-methionine (MET), 18F-FDG (FDG) and 201Tl-Cl (Tl) in brain radiation necrosis. Twenty-one years previously, the patient had undergone surgery and radiation therapy consisting of 60-Gy for ependymoma in the anterior horn of the right lateral ventricle. The clinical features consisting of frequent seizures of the left face and arm suddenly appeared 2 wk before admission. MRI depicted a Tl and T2-prolonged lesion in the right frontal lobe. Abnormally high uptake in this area demonstrated by MET-PET, FDG-PET, Tl-SPECT or HMPAO-SPECT suggested the presence of a recurrent tumor. A craniotomy was then performed and an intraoperative electrocorticogram showed continuous epileptic spikes in the lesion. The epileptic foci were resected and the histological features of the lesion were consistent with radiation necrosis. After surgery, the seizures disappeared and the postoperative examinations with MET-PET, FDG-PET, Tl-SPECT and HM-PAO-SPECT no longer showed abnormally high uptake. Hypermetabolism and hyperperfusion related to epileptic fits are therefore thought to result in high uptake of MET, FDG and Tl in radiation necrosis.

Regional cerebral blood flow in patients with schizophrenia: relevance to symptom structures

Regional cerebral blood flow (rCBF) was measured with technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography in 38 neuroleptic-treated schizophrenic patients. To improve the validity of the evaluation of symptomatology, we applied findings previously derived in a principal component analysis (PCA) of the Positive and Negative Syndrome Scale. The PCA had disclosed five orthogonal independent symptom structures (i.e., negative, hostile/excited, thought disordered, delusional/hallucinatory, and depressive components), and obtained factor scores for 70 schizophrenic subjects, including the present sample. Stepwise regression analysis elucidated some of the cortical regions in which relative rCBF predicted the severity of symptoms--namely, lateral and orbital prefrontal, lateral temporal, inferior parietal, and medial temporal regions. Findings suggested that symptom structures derived from PCA could prove helpful in elucidating the pathophysiology of neural mechanisms.

Impaired fatty acid uptake in ischemic but viable myocardium identified by thallium-201 reinjection

Iodine 123-labeled 15-iodophenyl-3-methyl-pentadecanoic acid (BMIPP) has been proposed as a potential myocardial fatty acid probe. We studied BMIPP uptake in ischemic myocardium identified by thallium reinjection. Fifty-five patients with coronary artery disease who had persistent defects on standard exercise-redistribution thallium imaging were investigated. Patients underwent exercise-redistribution-reinjection thallium and resting BMIPP imaging. BMIPP uptake less than that seen with thallium on reinjection imaging was observed in 105 (82%) of 128 myocardial segments with new fill-in after thallium reinjection and 87 (37%) of 238 segments with reversible thallium defects. In contrast, only 32 (19%) of 166 segments with no fill-in showed discordantly decreased BMIPP uptake. Quantitative analysis showed reduction in BMIPP activity compared with differential uptake of thallium, an index of resting myocardial perfusion, especially in the area of fill-in (53.5% +/- 15.0% vs 76% +/- 12.1% of peak; p<0.01). These observations are consistent with impaired fatty acid uptake in ischemic myocardium, particularly in the area of fill-in after thallium reinjection.

Comparison of defect size between thallium-201 and technetium-99m tetrofosmin myocardial single-photon emission computed tomography in patients with single-vessel coronary artery disease

Defect size on exercise-rest technetium (Tc)-99m tetrofosmin myocardial perfusion imaging was compared with that on exercise-reinjection thallium-201 imaging with 20 patients with 1-vessel coronary artery disease. In each patient, exercise-reinjection thallium-201 single-photon emission computed tomography (SPECT) and exercise-rest Tc-99m tetrofosmin SPECT imaging were performed. For visual analysis of the obtained SPECT images, the left ventricular myocardium was divided into 20 segments based on 3 short-axis slices from the apical, middle, and basal ventricular levels. For quantitative analysis, a square region of interest was placed on the center of each segment which was used for visual analysis, and relative regional activity to the normal reference region was calculated for each segment. By visual interpretation of the images, exercise Tc-99m tetrofosmin imaging showed a smaller defect size than exercise thallium-201 imaging (6.9 +/- 3.9 vs 8.8 +/- 3.0 segments, p <0.01). In contrast, rest Tc-99m tetrofosmin imaging showed a defect size similar to that on reinjection thallium-201 imaging (5.9 +/- 3.6 vs 5.6 +/- 3.9 segments, p = NS). Similarly, the mean defect sizes during exercise determined by quantitative analysis were smaller on Tc-99m tetrofosmin SPECT than those on thallium-201 SPECT at all tested threshold cutoff points ranging from 50% to 70%, whereas there were no significant differences in defect sizes between rest Tc-99m tetrofosmin and reinjection thallium-201 imaging. These data indicate that exercise Tc-99m tetrofosmin SPECT defect size determined either by visual analysis or by quantitative analysis may be smaller than on exercise thallium-201 SPECT.

Effect of induced hypertension with angiotensin II infusion on biodistribution of 111in-labeled monoclonal antibody

We investigated whether induced hypertension could enhance tumor uptake of monoclonal antibody. 111In-DTPA-A7 (IgG1 against 40kD tumor associated glycoprotein) was injected into colon carcinoma xenografted mice which were subcutaneously implanted with micro-osmotic pump containing angiotensin II (AT-II). Biodistribution was observed in groups of mice infused with AT-II at rate of 0.5 micrograms/kg/min (L) or 1 microgram/kg/min (H) and compared with a group of mice infused with saline (S). Tumor uptake of 111In-A7 in L and H was 1.32 and 1.57 times greater than S at 48 h after intravenous injection of A7. Normal organ uptakes also tended to be increased by AT-II infusion. Further study is needed to get optimum effect of hypertensive treatment on biodistribution of radiolabeled MoAb.

Technetium-99m tetrofosmin uptake in lung cancer: comparison with thallium-201

Technetium-99m tetrofosmin and thallium-201 lung SPECT imaging were performed in a patient with adenocarcinoma of the lung. Significant activities in the lung lesion were clearly depicted on both technetium-99m tetrofosmin and thallium-201 SPECT imaging. The early uptake, delayed uptake ratios and retention indices of the tumor were 2.75, 2.39 and -1.31 for thallium-201 imaging and 3.09, 2.27 and -26.5 for technetium-99m tetrofosmin imaging, respectively. This preliminary report suggests that technetium-99m tetrofosmin may have potential as a tumor imaging agent.

Scintigraphic study of malignant melanoma with 123I-iodoamphetamine

N-isopropyl-p-I-123-iodoamphetamine (123I-IMP) is extracted by the brain in proportion to regional blood flow. It is particularly useful in the clinical assessment of various pathological conditions related to altered cerebral flow. Moreover, it has been reported that 123I-IMP is avidly incorporated into melanin and melanotic melanoma. We evaluated 123I-IMP scintigraphy using either planar or single photon emission tomography (SPET) studies in 10 patients with malignant melanoma. The patients were classified into two groups according to the tumour site: Group A, six patients with primary or metastatic cutaneous malignant melanoma of the extremity with planar scintigraphy; Group B, four patients with primary malignant melanoma of other organs with planar scintigraphy and SPET. In Group A, tumour uptake was demonstrated in four of six patients; in Group B, three of four patients had tumour accumulation on SPET and planar scintigraphy. SPET revealed the exact tumour localization, even in the case of a tumour located in the lung. These results suggest that planar scintigraphy using 123I-IMP is useful in the detection of malignant melanoma. Furthermore, more clear tumour localization is possible with SPET, even in the case of a tumour located in the lung.

Utility of iodine-123-BMIPP in the diagnosis and follow-up of vasospastic angina

Myocardial damage caused by vasospastic angina (VSA) may be detected by [123I]BMIPP, a beta-methyl-branched fatty acid. We investigated whether BMIPP could be used in the diagnosis and follow-up of patients with VSA.

METHODS

Thirty-two patients with VSA were studied with resting BMIPP-SPECT in comparison to stress perfusion imaging with either 201Tl or 99mTc-MIBI. During coronary arteriography, spasm was induced by provocative testing with acetylcholine or ergonovine, and only total or subtotal occlusion was considered positive. Decreased BMIPP uptake was semiquantitatively evaluated segmentally aided by polar map display.

RESULTS

Reduced BMIPP uptake was observed in 25 of 32 patients (78%), with complete or partial agreement between the BMIPP abnormality and coronary territory seen in 23 patients (72%). In contrast, a perfusion abnormality was seen in only 10 patients (31%). In the repeat BMIPP study (n = 23) during the follow-up period (average 206 days), 11 of 14 patients who showed BMIPP improvement also had improved angina attacks. Conversely, two of nine patients with nonimproved BMIPP showed improved symptoms (p < 0.05).

CONCLUSION

BMIPP can detect myocardial injury associated with VSA and may be useful in monitoring response to treatment.

Intense accumulation of Tc-99m MDP and Ga-67 in multiple periapical cemental dysplasia

A case of multiple periapical cemental dysplasia is presented and intensive accumulation of Tc-99m MDP and Ga-67 is described. A 53-year-old woman was admitted with an intermittent pain and swelling of the left buccal region. The radiograph showed multiple sclerotic masses covering entire periapical regions of the teeth, in both the maxilla and mandibula. Biopsy of the maxilla facilitated a definitive diagnosis of multiple periapical cemental dysplasia.

Myocardial viability assessment with technetium-99m-tetrofosmin and thallium-201 reinjection in coronary artery disease

Exercise-rest 99mTc-tetrofosmin myocardial perfusion images with a 2-day protocol was compared to exercise-redistribution-reinjection 201Tl images to assess the ability of 99mTc-tetrofosmin to detect viable myocardium.

METHODS

We studied 25 patients with coronary artery disease and regional or global left ventricular dysfunction. Myocardial SPECT images with 99mTc-tetrofosmin were obtained 10 min after injection during exercise and 1 and 3 hr after rest injection. Within 1 wk of the 99mTc-tetrofosmin study, exercise-redistribution-reinjection 201Tl SPECT imaging was performed.

RESULTS

Visual analysis demonstrated concordance between 201Tl and 99mTc-tetrofosmin imaging for defect reversibility in 126 of 209 segments (60%), with initial defects on both exercise 201Tl and 99mTc-tetrofosmin images. In the remaining discordant 83 segments (40%), 73 (88%) appeared nonreversible on 99mTc-tetrofosmin imaging but were reversible on 201Tl imaging.

CONCLUSION

On the basis of defect reversibility by visual analysis, exercise-rest 99mTc-tetrofosmin imaging underestimates myocardial viability compared to 201Tl reinjection imaging. The identification of viable myocardium with both 99mTc-tetrofosmin and 201Tl can be greatly enhanced to a similar degree if the severity of reduction in activity within nonreversible defects is considered. These two agents may provide comparable information about myocardial viability by quantitative analysis of defect severity.

Improved myocardial fatty acid utilization after percutaneous transluminal coronary angioplasty

Exercise-reinjection 201Tl imaging and resting 20-min and 3-hr BMIPP imaging were performed before and 4 mo after percutaneous transluminal coronary angioplasty (PTCA) in a patient with effort angina. Before PTCA, exercise 201Tl imaging showed decreased 201Tl activity in the septal wall, with significant fill-in on the reinjection 201Tl image. The resting 20-min BMIPP image showed decreased activity in the septal wall, with a slight redistribution on the 3-hr BMIPP image. The 201Tl and BMIPP images 4 mo after PTCA showed significant improvement in the 201Tl pattern and BMIPP uptake in the septal wall with no abnormally decreased activities.

[Effect of scatter correction on quantification of myocardial SPECT and application to dual-energy acquisition using triple-energy window method]

Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201Tl, 29% for 99mTc, 57% for 123I. Composite energy spectra were generated and separated by the TEW method. Combination of 99mTc and 201Tl was separated well, and 201Tl and 123I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123I and 99mTc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar may and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123I, 7-8% higher in 99mTc and 6% higher in 201Tl. Apparent count loss after scatter correction was 30% for 123I, 13% for 99mTc and 38% for 201Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation.

In vivo characterization of radioiodinated 2-(4-phenylpiperidino)cyclohexanol (vesamicol) analogs: potential radioligand for mapping presynaptic cholinergic neurons

Iodovesamicol analogs, radioiodinated at the ortho (1), meta(2) and para(3) positions of the 4-phenylpiperidine moiety, were evaluated as potential presynaptic cholinergic neuron mapping agents. Significant accumulation of m-[125I]iodovesamicol (mIV(2)) (about 3% of the injected dose) was noted in the rat brain with prolonged retention times. The accumulation of mIV(2) in the rat brain was decreased by 67% by 5 min pre-injection of dl-vesamicol(1 mumol/kg). Pre-injection of (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperdine[(+)-3-PPP](0.75 mumol/kg) did not markedly decrease the levels of radiotracers (oIV(1) and mIV(2)) in the rat brain. These results suggest that radioidinated m-iodovesamicol (mIV(2)) is suitable for use in presynaptic cholinergic neuron mapping.

Dual-tracer autoradiography using 125I-iomazenil and 99Tcm-HMPAO in experimental brain ischaemia

To investigate the utility of neuroreceptor imaging in ischaemic cerebrovascular disorders, dual-tracer autoradiography using 99Tcm-hexamethylpropyleneamine oxime (HMPAO) for the evaluation of cerebral blood flow and 125I-iomazenil for the evaluation of central-type benzodiazepine receptor density was performed in experimental brain ischaemia created by occlusion of the unilateral middle cerebral artery of the rat. In the acute phase of ischaemia, 125I-iomazenil accumulation showed less of a decrease than 99Tcm-HMPAO in the cerebral cortex of the lateral convexity and in the lateral segment of the caudate putamen in the lesioned cerebral hemisphere. In the sub-acute phase, both 125I-iomazenil and 99Tcm-HMPAO accumulation increased in the lesion compared with the acute phase. A large accumulation of 99Tcm-HMPAO and 125I-iomazenil in the lesion was considered to be due to luxury perfusion and penetration of 125I-iomazenil hydrophilic metabolites from the blood into the brain tissue through the altered blood-brain barrier. In the chronic phase, 125I-iomazenil accumulation showed a more marked decrease than 99Tcm-HMPAO in the lesion. Moreover, the ipsilateral thalamus, which is remote from the lesion, revealed decreased 125I-iomazenil accumulation despite normal 99Tcm-HMPAO accumulation. Since the central-type benzodiazepine receptors are principally located not on the glial cells but on the neurons, the receptor density may exhibit a change that parallels the neuron density. These results suggest that central-type benzodiazepine receptor imaging is useful for the evaluation of neuronal damage when used in conjunction with brain perfusion imaging in ischaemic cerebrovascular disorders, except in the sub-acute phase.

A quantitative approach to technetium-99m ethyl cysteinate dimer: a comparison with technetium-99m hexamethylpropylene amine oxime

To develop non-invasive regional cerebral blood flow (rCBF) measurements using technetium-99m ethyl cysteinate dimer (99mTc-ECD) and single-photon emission tomography (SPET), the same graphical analysis as was described in our previous reports using technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) was applied to time-activity data for the aortic arch and brain hemispheres after intravenous injection of 99mTc-ECD. Hemispherical brain perfusion indices (BPI) for 99mTc-ECD showed a highly significant correlation (n = 22, r = 0.935, P = 0.0001) with those for 99mTc-HMPAO in 11 patients who underwent both tracer studies. Using both linear regression line equations between 99mTc-ECD BPI and 99mTc-HMPAO BPI and between 99mTc-HMPAO BPI and mean cerebral blood flow (CBF) values obtained from a xenon-133 inhalation SPET method in a previous study, 99mTc-ECD BPI was converted to 133Xe CBF values (y = 2.60 chi + 9.8). Then raw SPET images of 99mTc-ECD were converted to rCBF maps using Lassen's correction algorithm. In this algorithm, the correction factor alpha was fixed to 1.5, 2.6 and infinite. In the comparison of rCBF values for 99mTc-ECD SPET with those for 99mTc-HMPAO SPET in 396 regions of interest in the aforementioned 11 patients, the fixed correction factor alpha of 2.6 gave nearly the same rCBF values for 99mTc-ECD (50.1 +/- 16.9 ml/100 g/min, mean +/- SD) as for 99mTc-HMPAO (49.9 +/- 17.3 ml/100 g/min). In conclusion, the same non-invasive method as has been used in 99mTc-HMPAO studies is applicable to a 99mTc-ECD study for the measurement of rCBF without any blood sampling.

Comparison of 99Tcm-pyrophosphate, 201T1 perfusion, 123I-labelled methyl-branched fatty acid and sympathetic imaging in acute coronary syndrome

Among a group of patients (n = 15) with acute coronary syndrome, the results of using two new myocardial radiopharmaceuticals--123I-labelled 15-(p-iodo-phenyl)-3,R,S-methylpentadecanoic acid (BMIPP) and 123I-meta-iodobenzyl guanidine (MIBG)--were compared with dual 201Tl/99Tcm-pyrophosphate (Tl-PYP) imaging using single photon emission tomography (SPET). Defect scores were evaluated on a segment-by-segment basis for a total of 270 segments. For the 201Tl, BMIPP, and early and delayed MIBG studies, the mean (+/- S.D.) sums of defect scores were 9 +/- 8, 18 +/- 9, 22 +/- 12 and 29 +/- 9, respectively, revealing significantly higher scores for BMIPP and MIBG than 201Tl (P < 0.005). This was the case irrespective of various functional conditions, such as successful recanalization, failure of coronary angioplasty or restenosis. The culprit coronary artery was best identified using BMIPP, while MIBG SPET showed the most extensive defects. Normal perfusion with decreased BMIPP and MIBG uptake was frequently observed and associated with hypokinesis. 123I-BMIPP and MIBG are more sensitive for the detection of damaged myocardium, and the difference between perfusion and metabolism seems to reflect myocardial stunning.

Prominent uptake of Tl-201 by duodenal leiomyosarcoma after exercise myocardial perfusion study

Thallium-201 SPECT performed preoperatively for the evaluation of myocardial ischemia in a 72-year-old man with duodenal leiomyosarcoma demonstrated prominent focal uptake in the abdomen. Comparing a transaxial slice of SPECT through the abdominal uptake to the CT scan, the uptake was confirmed to be corresponding to the tumor. The tumor was delineated clearly, in good contrast to the surrounding normal intestine, which showed far less Tl-201 uptake than the tumor. In the delayed SPECT performed 3 hours after injection, although the intestinal activity became perceptible, the tumor still could be differentiated from the surrounding normal intestine. In this case, the exercise might be attributable to the initial low Tl-201 uptake by the normal intestine, which might otherwise have been an obstacle to Tl-201 scintigraphy for abdominal tumor detection. This case suggests the use of exercise for avoiding unfavorable intestinal activity, and the possibility of Tl-201 SPECT for abdominal tumor imaging.

[Value of 123I-BMIPP scintigraphy in patients with ischemic heart disease: comparison with exercise 201Tl SPECT]

To evaluate 123I labeled beta-methyl-branched fatty acid (BMIPP) myocardial uptake at rest in the segment with and without stress induced ischemia in patients with coronary artery disease, 123I-beta-methyl-branched fatty acid myocardial scintigraphy was performed at rest and was compared with the findings of stress-reinjection 201Tl myocardial scintigraphy in 31 patients with coronary artery disease. In 159 ischemic myocardial segments, equally decreased uptake on both reinjection 201Tl and fatty acid images was observed in 64 segments, more severely decreased uptake of fatty acid in 76 segments, and more severely decreased uptake of reinjection thallium in 19 segments. On the other hand, in 53 non-reversible defects, each patterns was observed in 41, 3, and 9 segments respectively. When comparing the ischemic segments with more reduced uptake of fatty acid than reinjection thallium (Group 1) and the ischemic segments with equally or less reduced fatty acid uptake than reinjection thallium (Group 2), wall motion was more severely impaired in Group 1 than in Group 2 (severe hypo- to dyskinesis was present in 32 of 54 segments in group 1 and in 21 of 75 segments in group 2, p < 0.005). In conclusion, in patients with coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection 201Tl in the segments with stress induced ischemia and wall motion was more impaired in these segments. BMIPP myocardial imaging may provide information on metabolic alterations at rest independent of perfusion abnormalities in patients with coronary artery disease.

[Phase II clinical trial of the radioactive strontium (89Sr) chloride agent, SMS. 2P for pain palliation in patients with prostate cancer with bone metastases]

The phase II clinical trial of a strontium (89Sr) chloride agent (SMS. 2P) was performed in 9 patients with painful bone metastases secondary to prostate cancer. After an intravenous administration, 89Sr circulated in the plasma and was rapidly cleared. Urinary excretion varied widely among the patients. No serious acute side effects were observed. A mild transient increase in pain was reported by 4 patients 2-4 days after administration, two of whom complained of mild nausea or vomiting. All symptoms improved and never became a clinical problem. There were some abnormal hematological parameters. In particular, a decrease in the platelet level seemed to be a marrow suppression due to 89Sr irradiation. It is difficult to discriminate between the effects of 89Sr and the progress of the disease using tumor markers. The pain level improved within 2 weeks after administration and the effect continued for at least 8 weeks, which improved the quality of life for these patients.

[Evaluation of myocardial fatty acid metabolism in the area of fill-in after thallium reinjection in patients with prior myocardial infarction]

Myocardial fatty acid utilization in the area with thallium fill-in after reinjection was assessed using 123I-labeled 15-(p-iodophenyl)3R,S-methylpentadecanoic acid (BMIPP). We studied 22 patients with prior myocardial infarction that revealed persistent defects on standard exercise-redistribution thallium imaging. In each patient, exercise-redistribution-reinjection thallium imaging was performed. Within two weeks of the thallium study, resting BMIPP imaging was performed 20 min after injection of BMIPP (148 MBq). Following qualitative analysis of the obtained thallium and BMIPP images, quantitative analysis was performed on the basis of relative regional uptake. Of 199 myocardial segments that showed persistent defects on exercise-redistribution images, 73 segments showed apparent fill-in on the reinjection images (fill-in positive), and the remaining 126 segments did not (fill-in negative). When BMIPP images were compared with the corresponding thallium reinjection images, reduced BMIPP uptake compared with thallium were frequently observed in the area of fill-in positive segments (65 of 73 segments, 89%). Quantitative analysis also showed decrease in BMIPP activity compared to thallium activity in the area of fill-in (49.7 +/- 16.1 vs. 65.8 +/- 16.0%, p < 0.001). In contrast, only 24 of the 126 fill-in negative segments (19%) showed lower BMIPP uptake than thallium. These results suggest that impaired fatty acid utilization in the area of thallium new fill-in after reinjection already exists at resting condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of radioiodinated analogs of 2-(4-phenylpiperidino)cyclohexanol (vesamicol) as vesamicol-like agent

Three iodovesamicol analogs, iodinated at the ortho, meta, and para positions of the 4-phenylpiperidine moiety, were synthesized and labeled with 125I by isotopic exchange reaction. Their potencies as a vesamicol-like drug were evaluated with competitive inhibition studies using (-)[3H]vesamicol. The radiochemical yields were 40-85%, the radiochemical purities exceeded 95% and their specific activities were 370-740 GBq/mmol. The descending order of binding affinity of the tested compounds against the vesamicol receptor was m-iodovesamicol > o-iodovesamicol > p-iodovesamicol. The receptor binding affinity of m-iodovesamicol (IC50 = 133 nM) was comparable with that of vesamicol (IC50 = 109 nM). Therefore, the meta position of the 4-phenylpiperidinyl fragment of vesamicol was the optimum site for iodination, and radioiodinated m-iodovesamicol may serve as a useful radiopharmaceutical for in vitro and in vivo studies of presynaptic cholinergic neurons in rats.

Variable portal circulation from inferior mesenteric vein assessed by per-rectal radionuclide administration

The intrahepatic distribution of radioactivity after the per-rectal administration of 201T-chloride and/or 99Tcm-pertechnetate was investigated in 177 studies in 149 patients with no liver disease or diffuse liver disease and compared with that of 99Tcm-stannous (99Tcm-Sn) colloid scintigrams. The patients were classified into two groups: distribution of intrahepatic radioactivity of 201Tl and/or 99Tcm-pertechnetate scintigrams similar to (homogeneous) or different from (heterogeneous) that of 99Tcm-Sn-colloid scintigrams. The heterogeneous group was divided into three subgroups: increased radioactivity of the right lobe (right dominant pattern), increased radioactivity of the left lobe (left dominant pattern) and uneven distribution of radioactivity in both lobes (uneven pattern). Of the 80 patients in whom the studies were performed in the supine position at rest, 14 (17.5%) showed a heterogeneous pattern (8 right dominant, 4 left dominant, 2 uneven) and 66 (82.5%) a homogeneous pattern. In the 97 patients allowed free body movement, 6 (6.2%) showed a heterogeneous (1 right dominant, 5 left dominant) and 91 (93.8%) a homogeneous pattern. A significant difference in the incidence of heterogeneous distribution between the resting and free body movement groups was found (P < 0.05). One patient with a left dominant pattern after free body movement with 201Tl showed a right dominant pattern at rest in the 99Tcm-pertechnetate study. It is concluded that a heterogeneous intrahepatic distribution of inferior mesenteric vein blood is sometimes observed and that the distribution of portal vein blood flow seems to be affected by the patient's positioning and free body movement.

Left ventricular functional reserve in nonobstructive hypertrophic cardiomyopathy: evaluation by continuous left ventricular function monitoring

The cardiac functional response to exercise in patients with nonobstructive hypertrophic cardiomyopathy (HCM) was evaluated using a continuous ventricular function monitor with a cadmium telluride detector (CdTe-VEST).

METHODS

Supine ergometric exercise was performed under CdTe-VEST monitoring in 41 patients with nonobstructive HCM (34 men and 7 women, age 18-72 yr, mean 51 yr) and 15 patients without cardiac disease (9 men and 6 women, age 36-56 yr, mean 49 yr).

RESULTS

Although 20 of 41 patients with HCM maintained a LVEF above baseline at peak exercise (Group A), 21 did not show an EF increase at peak exercise (Group B). Exercise duration and work load in Group A were longer and higher, respectively, than in Group B. Resting EF in Group B (72 +/- 7.7%) was significantly higher than that in Group A (65 +/- 8.2%) and the control group (62 +/- 5.9%). The EF increase from baseline to EF overshoot during recovery and the time to EF overshoot were lower and longer, respectively, in Group B than in Group A and the control group. Septal wall thickness and the septum-to-posterior-wall-thickness ratio between Groups A and B were not different. ST-segment depression was observed in all 21 Group B patients and in 8 of the Group A patients.

CONCLUSION

In patients with nonobstructive HCM, left ventricular dysfunction during exercise and during recovery was frequently observed but was not related to the degree of septal wall hypertrophy. The CdTe-VEST is a useful means to evaluate left ventricular functional reserve to exercise in patients with HCM.

Effects of head elevation on intracranial hemodynamics in patients with ventriculoperitoneal shunts

The present study was performed to investigate the effects of head elevation on intracranial hemodynamics in patients with ventriculoperitoneal (VP) shunts. The series included 35 hydrocephalic patients and five individuals without hydrocephalus who were used as controls. The hydrocephalic patients were divided into three groups: 15 patients who received VP shunts with a differential-pressure valve (DP group); 11 who received VP shunts with a variable-resistance valve (VR group), and 13 hydrocephalic patients (Hyd group) who had not received shunts (four underwent VP shunts later). The cerebral blood flow (CBF) of patients in the supine and upright positions was measured by technetium-99m hexamethylpropylenamine oxide (HMPAO) single-photon emission computerized tomography in each patient, using the subtraction technique. Cerebral perfusion pressure (CPP) was taken as the difference between the mean arterial blood pressure and ventricular fluid pressure, both referenced to the level of the foramen of Mono. The patients' heads were elevated stepwise from supine to upright. Percent changes of the mean CBF in the upright position (% delta mCBFupr) were 24.9% +/- 4.3% (mean +/- standard error of the mean) in the DP group, 6.2% +/- 2.7% in the VR group, 3.5% +/- 2.6% in the Hyd group, and 4.5% +/- 2.2% in the control group. Patients in the DP group showed a pathological increase in CPP with head elevation, whereas those in the Hyd and VR groups showed a physiological decrease in CPP. Three patients with differential-pressure valves, whose % delta mCBFupr was markedly high, developed low-intracranial pressure syndrome. In conclusion, shunted patients with a DP valve showed pathological intracranial hemodynamics in the upright position. This pathological hemodynamic stress in patients with long-standing differential-pressure valve implantation may induce pathological changes in the brain such as subependymal gliosis.