Relationship between the trochlear groove angle and patellar cartilage morphology defined by 3D spoiled gradient-echo imaging.

OBJECTIVE: To examine whether the femoral trochlear groove angle (TGA) is a determinant of the patellar cartilage volume and patellar cartilage damage. MATERIALS AND METHODS: Patellar cartilage was evaluated by MR imaging in 66 patients (22 males and 44 females) with knee pain. Fat-suppressed 3D spoiled gradient-echo images were used to calculate the cartilage volume and to grade the cartilage damage. The proximal and distal TGAs were measured from axial PD-weighted FSE MR images with fat suppression. RESULTS: For every increase in the TGA at the distal femur, the patellar cartilage volume was significantly increased by 6.07 × 10(-3) cm(3) (95% CI: 1.27 × 10(-3), 10.9 × 10(-3)) after adjustment for age, gender, and patellar bone volume (P < 0.05). The MR grade of medial patellar cartilage damage progressed as the distal TGA became narrower, although there was no significant correlation between the distal TGA and the MR grading of patellar cartilage damage. CONCLUSION: A more flattened distal TGA was associated with increased patellar cartilage volume. However, there was no association between TGA and patellar cartilage defects.

Relationship between cartilage volume using MRI and Kellgren-Lawrence radiographic score in knee osteoarthritis with and without meniscal tears.

OBJECTIVE: The purpose of our study was to evaluate the correlation between the Kellgren-Lawrence (KL) radiographic score and the femoral and tibial cartilage volumes determined by MRI in patients with knee osteoarthritis. The effect of meniscal tears and extrusion on the cartilage volume was also examined. SUBJECTS AND METHODS: Knee cartilage was evaluated by MRI in 74 patients (20 men and 54 women) who were categorized according to the KL score. Sagittal fat-suppressed 3D spoiled gradient-echo images were obtained to calculate the cartilage volume. The cartilage volume was determined for the lateral femoral cartilage, medial femoral cartilage, lateral tibial cartilage, and medial tibial cartilage. The femoral condylar bone volume was measured to adjust for bone size in each cartilage volume measurement. RESULTS: After adjusting for age, sex, and femoral condylar bone volume, the cartilage volumes were significantly different between the grades in all compartments. Additionally, significant correlations were observed between the KL score and the adjusted cartilage volumes of lateral femoral cartilage and lateral tibial cartilage without a meniscal tear and between the KL score and the adjusted cartilage volume of medial femoral cartilage with and without a meniscal tear. CONCLUSION: These findings showed a significant negative association between cartilage volume and the KL score. The cartilage volume of medial femoral cartilage may be more affected by the severity of osteoarthritis grade than the presence of a meniscal tear. In contrast, the cartilage volume in the lateral tibiofemoral compartment may be easily affected by the presence of a meniscal tear.

MRI of soft-tissue tumors: fast STIR sequence as substitute for T1-weighted fat-suppressed contrast-enhanced spin-echo sequence.

OBJECTIVE: The purpose of this study was to assess the value of the fast STIR sequence in comparison with the T1-weighted fat-suppressed contrast-enhanced sequence in the evaluation of soft-tissue tumors. MATERIALS AND METHODS: Sixty-seven soft-tissue tumors imaged with both STIR and T1-weighted fat-suppressed contrast-enhanced sequences were evaluated. The signal-to-noise and contrast-to-noise ratios of the tumors in comparison with normal muscle, bone marrow, and fat were measured. Subjective image contrast between soft-tissue tumors and the nearest normal tissue was evaluated by two observers. The observers classified the soft-tissue tumors as benign or malignant using a 5-point scale, and sensitivity, specificity, and accuracy were calculated. The results of the two readings were assessed with receiver operating characteristic analysis. RESULTS: The contrast-to-noise ratios of all tumors in comparison with muscle (p < 0.01), bone marrow (p < 0.05), and fat (p < 0.05) were significantly higher on the fast STIR images than on the T1-weighted fat-suppressed contrast-enhanced images. Both observers' mean ratings of benign, malignant, and all tumors in comparison with muscle on fast STIR images were significantly higher than those on T1-weighted fat-suppressed contrast-enhanced images. For both observers, the mean sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve in evaluation of the fast STIR images did not differ significantly from those in evaluation of the T1-weighted fat-suppressed contrast-enhanced images. CONCLUSION: The fast STIR sequence is excellent for evaluation of soft-tissue tumors, and contrast-enhancement is not always needed.

Findings of hepatopulmonary syndrome on breath-hold perfusion SPECT-CT fusion images.

Pulmonary perfusion SPECT-CT fusion images were used to characterize CT manifestations of intrapulmonary arteriovenous communications (AVC) causing right-to-left shunt and hepatopulmonary syndrome (HPS). After scanning the whole body and obtaining multiple view images of the lung, deep-inspiratory breath-hold (DIBrH) SPECT was obtained in 2 patients with HPS, which was automatically and three-dimensionally co-registered with DIBrH CT. In both patients, the whole body scan depicted systemic organs and confirmed the existence of right-to-left shunt. DIBrH SPECT-CT fusion images showed that perfusion defects were predominantly located at subpleural reticulo-nodular opacities and/or dilated vessels in the lung base. Subpleural reticulo-nodular opacities and/or dilated vessels in the lung base appear to be characteristic CT manifestation of intrapulmonary AVC in HPS.

Relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism: assessment with breath-hold SPECT-CT pulmonary angiography fusion images.

PURPOSE: The relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism (PTE) was comprehensively assessed on deep-inspiratory breath-hold (DIBrH) perfusion SPECT-computed tomographic pulmonary angiography (CTPA) fusion images. MATERIALS AND METHODS: Subjects were 34 acute PTE patients, who had successfully performed DIBrH perfusion SPECT using a dual-headed SPECT and a respiratory tracking system. Automated DIBrH SPECT-CTPA fusion images were used to assess the relation between lung perfusion defects and intravascular clots detected by CTPA. RESULTS: DIBrH SPECT visualized 175 lobar/segmental or subsegmental defects in 34 patients, and CTPA visualized 61 intravascular clots at variable locations in 30 (88%) patients, but no clots in four (12%) patients. In 30 patients with clots, the fusion images confirmed that 69 (41%) perfusion defects (20 segmental, 45 subsegmental and 4 lobar defects) of total 166 defects were located in lung territories without clots, although the remaining 97 (58%) defects were located in lung territories with clots. Perfusion defect was absent in lung territories with clots (one lobar branch and three segmental branches) in four (12%) of these patients. In four patients without clots, nine perfusion defects including four segmental ones were present. CONCLUSION: Because of unexpected dissociation between intravascular clots and lung perfusion defects, the present fusion images will be a useful adjunct to CTPA in the diagnosis of acute PTE.

A stripe sign on 99mTc-Technegas SPECT in pulmonary emphysema.

OBJECTIVE: By focusing on a stripe sign (interposed preserved radioactivity between central defects and pleural surface of the lung), the cross-sectional ventilation difference between the central and peripheral lung in pulmonary emphysema was evaluated on Tc-Technegas SPECT, and compared with other forms of chronic obstructive pulmonary disease (COPD). METHODS: Technegas and perfusion SPECT were performed in 47 patients with relatively advanced emphysema, 15 patients with other forms of COPD without alveolar destruction and six controls. The presence or absence of a stripe sign was evaluated at upper, middle and lower lung zones on both SPECT. At stripe sign-positive lung zones on Technegas SPECT in pulmonary emphysema, the pattern of low attenuation areas (LAAs) distribution on X-ray CT was also evaluated. RESULTS: Of the total of 282 lung zones in patients with emphysema, a stripe sign was positive on Technegas SPECT at 153 (54.2%) zones in 27 (57.4%) patients, although less frequently positive on perfusion SPECT at 166 (58.8%) zones in 30 (63.8%) patients. This sign was negative on Technegas SPECT throughout the stripe sign-negative zones on perfusion SPECT. Throughout the lung zones in controls and patients with other forms of COPD, this sign was negative both on Technegas and perfusion SPECT. On X-ray CT, 124 (81%) of 153 stripe-positive lung zones on Technegas SPECT in pulmonary emphysema showed central lung-dominant LAA. CONCLUSION: In contrast to other forms of COPD, a stripe sign was frequently positive on Technegas SPECT in relatively advanced emphysema, with central-lung dominant LAA on X-ray CT. Relative preservation of peripheral lung ventilation seems to be a characteristic feature of this disease, indicating a lower susceptibility of the peripheral lung for alveolar destruction.

Automated breath-hold perfusion SPECT/CT fusion images of the lungs.

OBJECTIVE: The purpose of this study was to evaluate the clinical applicability and feasibility of deep-inspiratory breath-hold (DIBrH) perfusion SPECT for improving adverse respiratory motion effects and for accuracy of SPECT/CT image fusion. MATERIALS AND METHODS: Eighty-seven consecutive patients with chronic obstructive pulmonary disease (COPD) (n = 43), acute pulmonary thromboembolism (PTE) (n = 26), and interstitial lung disease (ILD), (n = 18), underwent respiratory-monitored DIBrH SPECT with a dual-headed SPECT system. Two COPD and four acute PTE patients were excluded because of inappropriate scanning due to DIBrH difficulty. DIBrH SPECT was automatically fused with DIBrH CT. Perfusion defect clarity and heterogeneity and SPECT/CT matching were compared between DIBrH SPECT and non-breath-hold SPECT. RESULTS: Compared with non-breath-hold SPECT, DIBrH SPECT significantly enhanced defect clarity in acute PTE (p < 0.0001) and perfusion heterogeneity (coefficient of variations [CV] of pixel counts) in COPD and ILD (p < 0.0001). CV in COPD was also better correlated with lung diffusing capacity for carbon monoxide (p < 0.05). DIBrH SPECT also significantly improved SPECT/CT matching (p < 0.0001), with excellent matching of CT lung internal landmarks and pathology with corresponding defects. Fusion images confirmed wedge-shaped defects extending along specific pulmonary arterial branches in acute PTE and heterogeneous defects associated with airway or lung parenchymal abnormalities in COPD and ILD, with perfusion distribution consistent with lung CT attenuation changes. CONCLUSION: DIBrH SPECT is acceptable for routine application to improve respiratory motion effects and accuracy of SPECT/CT image fusion. Confirmative perfusion-morphologic correlation with reliable fusion images appears useful for clarifying the cause of perfusion defects and abnormal lung CT attenuation.

Kinematic MRI of the normal ankle ligaments using a specially designed passive positioning device.

BACKGROUND: Knowledge of the normal MRI appearances of the ankle ligaments and tendons is particularly important in the diagnosis of ankle sprains. In most clinical practices, the ankle is imaged in a neutral position with standard imaging planes and sequences. The purpose of our study was to investigate whether passive positioning influences the MRI appearances of the ligaments of the ankle. METHODS: The axial and coronal T1-weighted MR images obtained from 10 subjects were reviewed by two musculoskeletal radiologists. The following imaging planes were used: dorsiflexion with inversion, dorsiflexion with neutral, dorsiflexion with eversion, neutral with inversion, neutral, neutral with eversion, plantarflexion with inversion, plantarflexion with neutral, and plantarflexion with eversion. A subjective rating system was used to determine the optimal imaging plane and position for individual ligaments in each volunteer. Each ligament was rated on a scale (of 1 to 6). RESULTS: There were significant differences in the appearances of the anterior talofibular (p = 0.0002), calcaneofibular (p < 0.0001), and posterior talofibular (p < 0.0001) ligaments between the optimal and least optimal ankle positions in the axial plane, and in those of the (plantar calcaneonavicular) spring (p < 0.0001), tibiocalcaneal (p < 0.0001), posterior tibiotalar (p = 0.0087) and posterior talofibular (p = 0.0213) ligaments in the coronal plane. CONCLUSIONS: Kinematic MRI of the ankle is feasible and appears to improve visualization of ankle ligaments compared to MRI.

A practical synthesis of (S)-2-cyclohexyl-2-phenylglycolic acid via organocatalytic asymmetric construction of a tetrasubstituted carbon center.

[reaction: see text] A concise and enantioselective synthesis of (S)-2-cyclohexyl-2-phenylglycolic acid as a key intermediate for (S)-oxybutynin is reported. The crucial asymmetric tetrasubstituted carbon center was constructed with excellent stereoselectivity through the proline-catalyzed direct asymmetric aldol reaction between cyclohexanone and ethyl phenylglyoxylate under mild conditions.

Investigation of computer-aided diagnosis system for bone scans: a retrospective analysis in 406 patients.

OBJECTIVE: The aim of this study was to investigate the diagnostic ability of a completely automated computer-assisted diagnosis (CAD) system to detect metastases in bone scans by two patterns: one was per region, and the other was per patient. MATERIALS AND METHODS: This study included 406 patients with suspected metastatic bone tumors who underwent whole-body bone scans that were analyzed by the automated CAD system. The patients were divided into four groups: a group with prostatic cancer (N = 71), breast cancer (N = 109), males with other cancers (N = 153), and females with other cancers (N = 73). We investigated the bone scan index and artificial neural network (ANN), which are parameters that can be used to classify bone scans to determine whether there are metastases. The sensitivities, specificities, positive predictive value (PPV), negative predictive value (NPV), and accuracies for the four groups were compared. Receiver operating characteristic (ROC) analyses of region-based ANN were performed to compare the diagnostic performance of the automated CAD system. RESULTS: There were no significant differences in the sensitivity, specificity, or NPV between the four groups. The PPVs of the group with prostatic cancer (51.0 %) were significantly higher than those of the other groups (P < 0.01). The accuracy of the group with prostatic cancer (81.5 %) was significantly higher than that of the group with breast cancer (68.6 %) and the females with other cancers (65.9 %) (P < 0.01). For the evaluation of the ROC analysis of region-based ANN, the highest Az values for the groups with prostatic cancer, breast cancer, males with other cancers, and females with other cancers were 0.82 (ANN = 0.4, 0.5, 0.6, 0.7, and 0.8), 0.83 (ANN = 0.7), 0.81 (ANN = 0.5), and 0.81 (ANN = 0.6), respectively. CONCLUSION: The special CAD system "BONENAVI" trained with a Japanese database appears to have significant potential in assisting physicians in their clinical routine. However, an improved CAD system depending on the primary lesion of the cancer is required to decrease the proportion of false-positive findings.

Unusual anti-selective asymmetric conjugate addition of aldehydes to nitroalkenes catalyzed by a biphenyl-based chiral secondary amine.

Unusual anti-selectivity was observed in the conjugate addition of aldehydes to nitroalkenes, when a biphenyl-based chiral secondary amine was used as catalyst.

Intrabullous ventilation in pulmonary emphysema: assessment with dynamic xenon-133 gas SPECT.

PURPOSE: Intrabullous ventilation in patients with pulmonary emphysema (PE) was cross-sectionally evaluated using dynamic xenon-133 gas single photon emission computed tomography (SPECT). METHODS: Fifty-two patients with PE with a total of 109 bullae of more than 4 cm in maximum diameter underwent xenon-133 gas SPECT. The real xenon-133 gas half-clearance time (T1/2) at each bulla was compared with that at the surrounding lung in the same lobe. The emphysema subtype of the surrounding lung was classified into centrilobular, panlobular, and paraseptal on computed tomography (CT). RESULTS: All bullae except for one in all patients showed xenon-133 gas wash-in. Of the 108 bullae with wash-in, 95 (87.9%) bullae in 46 (88%) patients showed marked xenon-133 gas retention with a T1/2 beyond 110 s (mean: 184 s ± 91). The surrounding lungs of these bullae also showed marked retention with a T1/2 of greater than 100 s (mean: 174 s ± 82), and the majority (N=92, 96.8%) were centrilobular or panlobular on CT. The remaining 13 (12.0%) bullae in six (11%) patients showed minimal retention with a T1/2 of less than 80 s (mean: 62 s ± 11), regardless of no significant difference in size compared with the bullae with marked retention. All the surrounding lungs of these bullae except for one also showed minimal retention with a T1/2 of less than 70 s (mean: 60 s ± 18), which was significantly less compared with that of the bullae with marked retention (P<0.0001), and the majority (N=11, 84.6%) were paraseptal with or without an interstitially fibrotic change and predominantly located at the lower lung lobe on CT. The T1/2 of the 108 bullae with xenon-133 gas wash-in was significantly correlated with that of the surrounding lungs (r=0.884, P<0.0001). CONCLUSION: Intrabullous ventilation in patients with PE appears to depend on the ventilation status of the surrounding lung, and bullae with the surrounding lungs of paraseptal-type emphysema tend to show minimal air trapping. Xenon-133 gas SPECT is useful for assessment of the interaction between intrabullous and surrounding lung's ventilation, which is difficult on CT.

MR imaging of meniscal tears: comparison of intermediate-weighted FRFSE imaging with intermediate-weighted FSE imaging.

PURPOSE: We compared intermediate-weighted fast spin-echo (IW-FSE) images with intermediate-weighted fast-recovery FSE (IW-FRFSE) images in the diagnosis of meniscal tears. MATERIALS AND METHODS: First, 64 patients were recruited, and the arthroscopic findings (n = 40) and image analysis (n = 19) identified 59 torn menisci with 36 patients. Both the diagnostic performance and image quality in assessing meniscal tears was evaluated for IW-FSE and IW-FRFSE images using a four-point scale. Signal-to-noise ratio (SNR) calculation was performed for both sets of images. RESULTS: IW-FRFSE image specificity (100 %) for diagnosing the posterior horn of the medial meniscus (MM) tear with reader 1 was significantly higher than that of IW-FSE images (90 %). Mean ratings of the contrast between the lesion and normal signal intensity within the meniscus were significantly higher for the IW-FRFSE image ratings than the IW-FSE images in most meniscal tears. Mean SNRs were significantly higher for IW-FSE images than for IW-FRFSE images (P < 0.05). CONCLUSIONS: IW-FRFSE imaging can be used as an alternative to the IW-FSE imaging to evaluate meniscal tears.

Malignant versus benign vertebral compression fractures: can we use bone SPECT as a substitute for MR imaging?

OBJECTIVE: To determine whether it is possible to use bone single-photon emission tomography (SPECT) as a substitute for magnetic resonance (MR) imaging for differentiating malignant from benign vertebral compression fractures (VCFs). METHODS: Ninety-seven fractures in patients who underwent both bone SPECT and MR imaging were included in our study. These 97 fractures were divided into two groups: malignant and benign VCFs. Two radiologists separately classified VCFs into malignant and benign according to the criteria for classifying VCFs on the planar, SPECT, and MR imaging as malignant or benign, as reported by many investigators earlier. In addition, 97 fractures were divided into two groups based on the MR images: VCFs with complete and partial replacement of the normal fatty marrow. The sensitivity, specificity, and accuracy of both the observers were calculated. RESULTS: The accuracy of the MR images was significantly greater than that of the SPECT images for both the observers (observer 1, P<0.001; observer 2, P<0.05). However, there were no significant differences in sensitivity, specificity, and accuracy for differentiating malignant from benign VCFs with complete replacement of the normal fatty marrow for both the observers [(observer 1: sensitivity, P=0.85; specificity, P=0.58; accuracy, P=0.63), and (observer 2: sensitivity, P=0.85; specificity, P=0.58; accuracy, P=0.87)]. CONCLUSION: Bone SPECT may be comparable with MR imaging for differentiating malignant from benign VCFs, especially, in the case of VCFs with a complete replacement of the normal fatty marrow.

Impaired lung 123I-MIBG uptake on SPECT in pulmonary emphysema.

UNLABELLED: The aim of this study was to evaluate impaired lung uptake of (123)I-metaiodobenzylguanidine ((123)I-MIBG) on SPECT, compared with perfusion SPECT and morphologic CT, in patients with pulmonary emphysema (PE). METHODS: (123)I-MIBG SPECT was performed at 15 min and 4 h after intravenous injection of (123)I-MIBG in 36 PE patients with a history of smoking and variable-extent low-attenuation areas on CT, indicative of emphysematous changes, and in 16 controls with no history of smoking and no noticeable low-attenuation areas. The distribution of (123)I-MIBG was compared with that of low-attenuation areas on CT and perfusion on SPECT at the base of the 180 lung lobes of the PE patients. Total-lung (123)I-MIBG kinetics were calculated, including early and delayed lung-to-mediastinum uptake ratios and washout rate. RESULTS: The controls showed a fairly uniform lung (123)I-MIBG distribution nearly consistent with perfusion. PE patients had heterogeneous (123)I-MIBG defects showing frequent discordance with low-attenuation areas or perfusion distribution; (123)I-MIBG defects were more extensive than low-attenuation areas in 76 lobes (42.2%) of 31 patients (86%) and more extensive than perfusion defects in 44 lobes (24.4%) of 22 patients (61%). (123)I-MIBG defects were seen regardless of the absence of noticeable low-attenuation areas and perfusion defects in 19 lobes (10.5%) of 16 patients (44%). All total-lung (123)I-MIBG kinetic parameters in PE patients were significantly lower than the control values (P < 0.0001), with significant correlation with alveolar-arterial oxygen tension gradient but without correlation with the extent of perfusion defects or low-attenuation areas. CONCLUSION: (123)I-MIBG SPECT allows evaluation of lung pathophysiology in PE independently of perfusion SPECT or morphologic CT, and impairment of lung (123)I-MIBG uptake may be more extensive than perfusion or morphologic abnormalities in PE.

Steal phenomenon-induced lung perfusion defects in pulmonary arteriovenous fistulas: assessment with automated perfusion SPECT-CT fusion images.

PURPOSE: Lung perfusion impairment in patients with pulmonary arteriovenous fistula (AVF) was evaluated by automated deep inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. METHODS: Participants were 14 patients with a single (N=6) or multiple nodular AVFs (N=8) diagnosed by contrast-enhanced CT scan and/or pulmonary angiography. After the injection of 185MBq Tc-99m-macroaggregated albumin, a whole-body scan was obtained to quantify an intrapulmonary right-to-left shunt. Subsequently, DIBrH SPECT was obtained using the continuous rotating acquisition mode of a dual-headed SPECT system, which was automatically coregistered with DIBrH CT. The anatomic relationship between AVF and perfusion defects was assessed on the fusion images. RESULTS: The whole-body scan depicted systemic organs indicating the presence of an intrapulmonary right-to-left shunt in all the patients. DIBrH SPECT showed 34 perfusion defects in these patients, which were located at the AVF and in the surrounding lungs of the AVF on the fusion images, regardless of the absence of morphologic abnormality on CT in all the patients. These defects were considered to be caused by the 'steal phenomenon' associated with the high and fast pulmonary arterial flow to each AVF, which were more extensive and severe in the multiple AVFs compared with a single AVF (P=0.0012), occasionally extending to the entire lobe with AVF or even to the adjacent lobe. In five patients, the fusion images detected a total of six tiny AVFs with unexpectedly extensive 'steal phenomenon'-induced defects, which had been missed by other radiological imaging techniques. The summed value of the shunt index estimated by the whole-body scan and the lung perfusion defect extent estimated by DIBrH SPECT was significantly correlated with PaO2 in all the patients (P < 0.0001), with a better correlation compared with the shunt index alone. CONCLUSION: In addition to the right-to-left shunt, 'steal phenomenon'-induced perfusion defects are common in the surrounding lung of pulmonary nodular AVF and cause hypoxemia. DIBrH SPECT-CT fusion images contribute to the objective evaluation of 'steal phenomenon'-induced lung perfusion impairment in AVF and the detection of tiny, subtle AVFs that may be missed by other radiological imaging techniques.

Assessment of cross-sectional lung ventilation-perfusion imbalance in primary and passive pulmonary hypertension with automated V/Q SPECT.

PURPOSE: Cross-sectional lung ventilation (V)-perfusion (Q) imbalance in primary pulmonary arterial hypertension (PAH) and passive pulmonary hypertension (PH) was characterized by automated V/Q single-photon emission computed tomography (SPECT). MATERIALS AND METHODS: Technegas/macro-aggregated albumin SPECT-derived V/Q SPECT and V/Q profile were automatically built to characterize cross-sectional lung V-Q imbalance in 12 patients with primary (idiopathic or familial) PAH and 15 patients with passive PH associated with left ventricular dysfunction or failure. The abnormality of V/Q distribution in these patients was correlated with PaO2 and pulmonary arterial pressure and with lung morphologic changes on computed tomography (CT). RESULTS: Markedly low V/Q ratios (reverse V-Q mismatch) in the background lungs with heterogeneous V/Q distribution was seen in 12 of the 12 (100%) patients with primary PAH and in 10 of the 15 (66%) patients with passive PH, which were predominantly seen in the upper lung zone. Including these regions with reverse V-Q mismatch, the V/Q profile frequently showed flattened peaks with asymmetric and broadened V/Q distribution in all patients, with significant correlation between the standard deviation of V/Q ratios in the entire lungs and PaO2 and mean pulmonary arterial pressure (both; P<0.01). At the regions of the lungs with reverse V-Q mismatch, bronchial lumens compressed by dilated pulmonary arteries and heterogeneous lung attenuations were frequently seen on CT. CONCLUSION: Patients with primary PAH and passive PH seem to characteristically have a high prevalence of reverse V-Q mismatch indicative of an inadequate hypoxic vasoconstriction reflex on V/Q SPECT, frequently accompanied with heterogeneous lung attenuations and compressed airways on CT.

Lung ventilation-perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT.

PURPOSE: Tc-99m-Technegas-MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V-Q imbalance in patients with pulmonary emphysema. METHODS: V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V-Q imbalance. RESULTS: In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P < 0.0001 and P < 0.001, respectively), and a significant correlation was found between SD and A-aDO2 (P < 0.0001). CONCLUSIONS: V/Q quotient SPECT appears to be more sensitive to detect emphysematous lungs compared with morphologic CT in patients with emphysema. SD and kurtosis of V/Q profile can be adequate parameters to assess the severity of lung V-Q imbalance causing gas-exchange impairment in patients with emphysema.

Magnetic resonance imaging characteristics of tuberculous spondylitis vs. pyogenic spondylitis.

OBJECTIVE: To assess the magnetic resonance (MR) imaging features differentiating tuberculous spondylitis from pyogenic spondylitis. METHODS: MR imaging findings in 10 patients with tuberculous spondylitis were retrospectively compared with those of 13 patients with pyogenic spondylitis. RESULTS: There were significant differences in imaging criteria (paraspinal abnormal signal, paraspinal or intraspinal abscess, thoracic spine involvement, and abnormal signal around the facet joint). CONCLUSIONS: MR imaging is a very useful technique for differentiation of tuberculous spondylitis from pyogenic spondylitis.