Replaced posterior cerebral artery.

PURPOSE: Replaced posterior cerebral artery (PCA), defined as a hyperplastic anterior choroidal artery (AChA) supplying all branches of the PCA, is an extremely rare anatomical variation. To the best of our knowledge, there are only a few reports of replaced PCA. METHODS: Herein, we report a case of replaced PCA diagnosed by digital subtraction angiography. RESULTS: A 76-year-old woman visited a neurosurgical clinic because of headache and vertigo. Magnetic resonance imaging and magnetic resonance angiography incidentally revealed a left internal carotid artery aneurysm. She was referred to our hospital for further examination and treatment of the unruptured intracranial aneurysm. Left internal carotid angiography revealed a paraclinoid aneurysm. We also incidentally found an anomalous hyperplastic AChA distal to the aneurysm. This hyperplastic AChA supplied not only the AChA territory but also the entire PCA territory. No vessels that could be a normal AChA or posterior communicating artery were identified along the left internal carotid artery. Vertebral angiography demonstrated that the left PCA was not visualized. With these findings, we diagnosed anomalous hyperplastic AChoA in this case as replaced PCA. CONCLUSION: Careful imaging assessment is important to identify replaced PCA. Both direct findings of a hyperplastic AChA course and perfusion territory and indirect findings of the absence of the original PCA are useful in the diagnosis of replaced PCA.

Simultaneous intracranial and extracranial vertebral artery dissections: a case report.

Vertebral artery dissection can occur in intracranial or extracranial vertebral arteries. However, the simultaneous dissection of both intracranial and extracranial vertebral arteries is extremely rare. We describe a 45-year-old man with simultaneous intracranial and extracranial vertebral artery dissections in separate sites. The patient visited a neurosurgical clinic because of headache; he was diagnosed with right vertebral artery dissection and referred to our hospital. Magnetic resonance imaging showed an intramural hematoma and mild dilation of the external lumen in the right vertebral artery distal to the posterior inferior cerebellar artery. Magnetic resonance angiography revealed poor delineation of the entire right vertebral artery, including the proximal portion from the posterior inferior cerebellar artery. Computed tomography angiography revealed right extracranial vertebral artery dissection. Careful imaging assessment is thus important for identifying simultaneous intracranial and extracranial vertebral artery dissections.

Extremely long posterior cerebral artery P1 segment.

PURPOSE: Excluding aplasia and hypoplasia of the P1 segment of the posterior cerebral artery (PCA), anatomical variations in the PCA are rare. To our best knowledge, there are few reports of an extremely long P1 segment of the PCA. METHODS: Herein, we report a rare case of an extremely long P1 segment of the PCA, which was diagnosed by 1.5-T magnetic resonance angiography (MRA). RESULTS: A 96-year-old woman was transferred by ambulance to our hospital with impaired consciousness. Her symptom improved, and magnetic resonance imaging showed no significant findings. MRA revealed an extremely long P1 segment of the left PCA. The length of the P1 segment of the left PCA was 27.3 mm. The left posterior communicating artery (PCoA) was 20.9 mm, which is not considered long. The left anterior choroidal artery branched from the internal carotid artery distal to the PCoA branching position. Basilar artery fenestration was also incidentally identified. CONCLUSION: Careful imaging assessment was important for identifying the extremely long P1 segment of the PCA in the present case. This rare anatomical variation can also be confirmed by 1.5-T MRA.

Complete duplication of the posterior cerebral artery.

PURPOSE: Variations of the posterior cerebral artery (PCA) are rare, excluding aplasia or hypoplasia of the P1 segment. To the best of our knowledge, there are few reports of complete duplication of the PCA. METHODS: Herein, we report a case of complete duplication of the PCA diagnosed by 1.5 T magnetic resonance angiography. RESULTS: A 55-year-old woman visited our hospital for cerebrovascular disease screening. Magnetic resonance angiography revealed two right PCAs with similar diameters. One PCA originated as the P1 segment of the PCA branching from the basilar artery, and the other was the fetal-type posterior communicating artery (PCoA) branching from the internal carotid artery (ICA). Neither PCA supplied the right anterior choroidal artery (AChA) territory. Bilateral PCoAs branched from the same position as each ICA, respectively. The right AChA branched from the ICA distal to the PCoA branching position. CONCLUSION: Careful imaging assessment is important for identifying complete duplication of the PCA. In addition to the direct findings of AChA identification, the indirect findings of the PCoA branching position and that the PCAs did not supply the AChA territory were also useful for diagnosis in this case.

Conservative treatment for stable osteochondritis dissecans of the elbow before epiphyseal closure: effectiveness of elbow immobilization for healing.

BACKGROUND AND HYPOTHESIS: Stable lesions of osteochondritis dissecans (OCD) of the capitellum have been treated with activity restriction (AR), and the complete healing requires 1 or 2 years. Little is known about the effectiveness of elbow immobilization. We hypothesized that elbow immobilization would have positive effects on healing of stable OCD. METHODS: The study subjects were 43 patients (mean age: 12.2 years) with 43 stable OCD lesions of the prematured elbow (mean skeletal age score: 17.1 points of 0-27 points system). The subjects were divided into 3 groups: group A, AR without elbow immobilization, 22 cases; group B, splint (mean: 8.8 weeks) followed by AR, 9 cases; and group C, cast (mean: 3.7 weeks) followed by splint (mean: 7.3 weeks) and AR, 12 cases. The mean nonoperative observation period was 17.5 months (minimum three months). On anteroposterior radiographs of the elbow at 45 degrees of flexion, 5 observers independently assessed the healing of the capitellum, and the interobserver and intraobserver reliabilities were examined. The differences in outcomes among 3 groups were also examined. RESULTS: The interobserver and intraobserver reliabilities of the radiographic assessment were almost perfect (Cohen kappa value: 0.82 and 0.91, respectively). There were no significant differences in age, sports played, or stage of the lesion before the treatment. The proportion of patients returning to sports and the mean period required were 77% and 8.2 months in group A, 78% and 5.7 months in group B, and 83% and 4.4 months in group C, respectively. The proportion of patients showing ossification in the central aspect of the capitellum and the mean period required were 67% and 8.2 months in group A, 63% and 4.9 months in group B, and 91% and 1.9 months in group C, respectively. The proportion of patients showing complete healing and the mean period required were 41% and 16.4 months in group A, 67% and 7.0 months in group B, and 92% and 5.5 months in group C, respectively. Compared to group A, group C showed a significantly earlier return to sports (P = .034), a significantly shorter period required for ossification (P < .001), and significantly higher proportion of patients with complete healing (P = .012) within a significantly shorter period (P = .009). CONCLUSION: Elbow immobilization had positive effects on healing and enabled both an early return to sports and complete healing. Cast immobilization is recommended as a first choice of nonoperative treatment for stable OCD lesions of the elbow before epiphyseal closure.

Japanese multicenter database of healthy controls for [123I]FP-CIT SPECT.

PURPOSE: The aim of this multicenter trial was to generate a [123I]FP-CIT SPECT database of healthy controls from the common SPECT systems available in Japan. METHODS: This study included 510 sets of SPECT data from 256 healthy controls (116 men and 140 women; age range, 30-83 years) acquired from eight different centers. Images were reconstructed without attenuation or scatter correction (NOACNOSC), with only attenuation correction using the Chang method (ChangACNOSC) or X-ray CT (CTACNOSC), and with both scatter and attenuation correction using the Chang method (ChangACSC) or X-ray CT (CTACSC). These SPECT images were analyzed using the Southampton method. The outcome measure was the specific binding ratio (SBR) in the striatum. These striatal SBRs were calibrated from prior experiments using a striatal phantom. RESULTS: The original SBRs gradually decreased in the order of ChangACSC, CTACSC, ChangACNOSC, CTACNOSC, and NOACNOSC. The SBRs for NOACNOSC were 46% lower than those for ChangACSC. In contrast, the calibrated SBRs were almost equal under no scatter correction (NOSC) conditions. A significant effect of age was found, with an SBR decline rate of 6.3% per decade. In the 30-39 age group, SBRs were 12.2% higher in women than in men, but this increase declined with age and was absent in the 70-79 age group. CONCLUSIONS: This study provided a large-scale quantitative database of [123I]FP-CIT SPECT scans from different scanners in healthy controls across a wide age range and with balanced sex representation. The phantom calibration effectively harmonizes SPECT data from different SPECT systems under NOSC conditions. The data collected in this study may serve as a reference database.

Initial 'TTP Map-Defect' of Computed Tomography Perfusion as a Predictor of Hemorrhagic Transformation of Acute Ischemic Stroke.

BACKGROUND: Hemorrhagic transformation (HT) following acute ischemic stroke is a major problem, especially for the indication of reperfusion therapy including intravenous administration of recombinant tissue plasminogen activator (IV rt-PA). The specific predictive factors of HT have not yet been established. The present study evaluated the findings of computed tomography perfusion (CTP) images as predictors of subsequent HT to identify patients with low HT risk for reperfusion therapy such as IV rt-PA. METHODS: We retrospectively reviewed 68 consecutive stroke patients (41 males; mean age 72.9 years) with steno-occlusive lesions in the major trunk, including 10 patients who underwent IV rt-PA. Each HT was detected on a follow-up T2*-weighted magnetic resonance image until 2 weeks after stroke onset and categorized into four groups [hemorrhagic infarction (HI) type 1 and 2, and parenchymal hematoma (PH) type 1 and 2] according to the European Cooperative Acute Stroke Study (ECASS) classification. We assessed clinical features and radiological findings between the HT and non-HT groups or the PH2 and non-PH2 groups. The efficacy of initial time to peak (TTP) mapping of CTP for predicting HT or PH2 was evaluated. RESULTS: Thirty-four patients (50%) developed subsequent HT: 18 (52.9%) had HI and 16 (47.1%) had PH, including 9 PH2 patients (13.2%). IV rt-PA was not significantly associated with HT or PH2 occurrence. Forty of the 68 patients (59%) revealed defect areas on the initial TTP mapping (TTP map-defect), and 34 of these 40 patients (85%) developed secondary HT and 9 patients (22.5%) developed PH2. Initial 'TTP map-defect' was significantly associated with the occurrence of HT (p < 0.0001) and PH2 (p = 0.0070). Thirty of the 34 patients (88.2%) in the HT group experienced delayed recanalization of the occluded vessels, in contrast to only 8 of the 34 patients (23.6%) in the non-HT group. All patients of the PH2 group showed recanalization (p = 0.0042). In 40 'TTP map-defect'-positive patients, delayed recanalization was associated with the occurrence of HT (p < 0.0001) and PH2 (p = 0.0491). All 28 patients without 'TTP map-defect' did not develop HT, including 8 patients (28.6%) with delayed recanalization. CONCLUSIONS: Initial 'TTP map-defect' of CTP could accurately predict HT risk including PH2 risk and identify low-risk patients even in the delayed period.

[Carotid MRI of initial and recurrent plaques in patients with restenosis after endarterectomy: three case reports].

Restenosis after carotid endarterectomy (CEA) is one of most significant complications. There is no previous report about MRI findings of restenotic lesions and preoperative plaques. The purpose of this study was to evaluate the initial and recurrent plaques in patients with restenosis after CEA by using black-blood MRI (BB-MRI). Three patients who underwent carotid artery stenting for restenosis after CEA were included in this study. The relative signal intensities (rSI) of the initial and recurrent plaques were calculated with reference to the sternocleidomastoid muscle on T1-weighted images (T1WI) and the submandibular gland on T2-weighted images (T2WI). This study investigated the rSI characteristics and morphology of the initial and recurrent plaques. All patients had restenosis within 1 year after CEA. The rSI values of the preoperative lesion were not high on T1WI and were high on T2WI in all cases (T1WI/T2WI: 0.63/2.43 in Case 1, 1.00/1.29 in Case 2, and 1.13/1.70 in Case 3). The morphology of the initial plaques was eccentric in 2 cases and concentric in 1 case. The rSI values of restenosis were high on T2WI in all cases (T1WI/T2WI: 1.09/1.20 in Case 1, 1.31/1.50 in Case 2, and 1.23/1.70 in Case 3). The morphology of restenotic lesions was concentric in all cases. The high rSI on T2WI and concentricity of the restenosis after CEA suggest early restenosis (intimal hyperplasia). The low-iso rSI on T1WI and high rSI on T2WI of the preoperative plaques are associated with restenosis after CEA. BB-MRI may be useful to evaluate and predict restenosis after CEA. (Received: May 7, 2012, Accepted: September 10, 2012).

Relationship between stx genotype and Stx2 expression level in Shiga toxin-producing Escherichia coli O157 strains.

To determine the expression level of Shiga toxin (Stx) 2-related toxins (Stx2 and Stx2c) produced by each of 33 Stx-producing Escherichia coli (STEC) O157 strains, stx2 and stx2c mRNAs (stx2-related mRNA) were measured using real-time PCR with primers that recognize sequences common to stx2 and stx2c. The amount of Stx2 and Stx2c protein was measured using a reversed passive latex agglutination (RPLA) kit. Expression of stx2-related mRNA was significantly higher in STEC O157 strains carrying the stx2 gene (i.e., stx2, stx1/stx2, or stx2/stx2c) than in most strains that carried the stx2c gene but not the stx2 gene (i.e., stx2c or stx1/stx2c). RPLA might not measure the precise amount of each toxin variant; nevertheless, stx2-inclusive strains had 40-fold higher mean toxin titers than did strains that carried the stx2c gene but not the stx2 gene, with the exception of 1 stx2c strain. Interestingly, 1 stx2c strain that was isolated from a patient with severe hemorrhagic diarrhea had the highest stx2-related mRNA expression and the highest toxin titer of all 33 STEC O157 strains. Taken together, these findings indicated that measurement of stx2-related mRNA expression could reflect differences in production levels of toxins among STEC strains.