Prediction of overall survival in patients with hepatocellular carcinoma treated with Y-90 radioembolization by imaging response criteria.

PURPOSE: To evaluate the potential of imaging criteria in predicting overall survival of patients with hepatocellular carcinoma (HCC) after a first transcatheter arterial yttrium-90 radioembolization (TARE) MATERIALS AND METHODS: From October 2013 to July 2017, 37 patients with HCC were retrospectively included. There were 34 men and 3 women with a mean age of 60.5±10.2 (SD) years (range: 32.7-78.9 years). Twenty-five patients (68%) were Barcelona Clinic Liver Cancer (BCLC) C and 12 (32%) were BCLC B. Twenty-four primary index tumors (65%) were>5cm. Three radiologists evaluated tumor response on pre- and 4-7 months post-TARE magnetic resonance imaging or computed tomography examinations, using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, modified RECIST (mRECIST), European Association for Study of the Liver (EASL), volumetric RECIST (vRECIST), quantitative EASL (qEASL) and the Liver Imaging Reporting and Data System treatment response algorithm. Kaplan-Meier survival curves were used to compare responders and non-responders for each criterion. Univariate and multivariate Cox proportional hazard ratio (HR) analysis were used to identify covariates associated with overall survival. Fleiss kappa test was used to assess interobserver agreement. RESULTS: At multivariate analysis, RECIST 1.1 (HR: 0.26; 95% confidence interval [95% CI]: 0.09-0.75; P=0.01), mRECIST (HR: 0.22; 95% CI: 0.08-0.59; P=0.003), EASL (HR: 0.22; 95% CI: 0.07-0.63; P=0.005), and qEASL (HR: 0.30; 95% CI: 0.12-0.80; P=0.02) showed a significant difference in overall survival between responders and nonresponders. RECIST 1.1 had the highest interobserver reproducibility. CONCLUSION: RECIST and mRECIST seem to be the best compromise between reproducibility and ability to predict overall survival in patients with HCC treated with TARE.

Colorectal cancer (CRC) monitoring by 6-monthly 18FDG-PET/CT: an open-label multicentre randomised trial.

Background: [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18FDG-PET/CT) has high sensitivity for detecting recurrences of colorectal cancer (CRC). Our objective was to determine whether adding routine 6-monthly 18FDG-PET/CT to our usual monitoring strategy improved patient outcomes and to assess the effect on costs. Patients and methods: In this open-label multicentre trial, patients in remission of CRC (stage II perforated, stage III, or stage IV) after curative surgery were randomly assigned (1 : 1) to usual monitoring alone (3-monthly physical and tumour marker assays, 6-monthly liver ultrasound and chest radiograph, and 6-monthly whole-body computed tomography) or with 6-monthly 18FDG-PET/CT, for 3 years. A multidisciplinary committee reviewed each patient's data every 3 months and classified the recurrence status as yes/no/doubtful. Recurrences were treated with curative surgery alone if feasible and with chemotherapy otherwise. The primary end point was treatment failure defined as unresectable recurrence or death. Relative risks were estimated, and survival was analysed using the Kaplan-Meier method, log-rank test, and Cox models. Direct costs were compared. Results: Of the 239 enrolled patients, 120 were in the intervention arm and 119 in the control arm. The failure rate was 29.2% (31 unresectable recurrences and 4 deaths) in the intervention group and 23.7% (27 unresectable recurrences and 1 death) in the control group (relative risk = 1.23; 95% confidence interval, 0.80-1.88; P = 0.34). The multivariate analysis also showed no significant difference (hazards ratio, 1.33; 95% confidence interval, 0.8-2.19; P = 0.27). Median time to diagnosis of unresectable recurrence (months) was significantly shorter in the intervention group [7 (3-20) versus 14.3 (7.3-27), P = 0.016]. Mean cost/patient was higher in the intervention group (18 192 ± 27 679 € versus 11 131 ± 13 €, P < 0.033). Conclusion: 18FDG-PET/CT, when added every 6 months, increased costs without decreasing treatment failure rates in patients in remission of CRC. The control group had very close follow-up, and any additional improvement (if present) would be small and hard to detect. ClinicalTrials.gov identifier: NCT00624260.

High-dose transdermal nicotine in Parkinson's disease patients: a randomized, open-label, blinded-endpoint evaluation phase 2 study.

BACKGROUND AND PURPOSE: Studies of the effects of nicotine on motor symptoms in Parkinson's disease (PD) brought out discordant results. The aim of the present study was to evaluate the efficacy and safety of high doses of transdermal nicotine on motor symptoms in PD. METHODS: Forty PD patients were randomly assigned to a treated and untreated arm in an open-label study. Treated patients received increasing doses of nicotine to reach 90 mg/day by 11 weeks. This dosage was maintained for 28 weeks (W39) and then reduced over 6 weeks. Final evaluation was performed 6 weeks after washout. The main outcome measure was the OFF-DOPA Unified Parkinson's Disease Rating Scale (UPDRS) motor score measured on video recordings by raters blinded to the medication status of the patients. RESULTS: There was no significant difference in OFF-DOPA UPDRS motor scores between the nicotine-treated and non-treated groups, neither at W39 (19.4 ± 9.3 vs. 21.5 ± 14.2) nor considering W39 differences from baseline (-1.5 ± 12.1 vs. +0.9 ± 12.1). The 39-item Parkinson's disease questionnaire scores decreased in nicotine-treated patients and increased in non-treated patients, but the difference was not significant. Overall tolerability was acceptable, and 12/20 treated patients reached the maximal dosage. CONCLUSIONS: High doses of transdermal nicotine were tolerated, but our study failed to demonstrate significant improvement in UPDRS motor scores. Improvement in unblinded secondary outcomes (UPDRS-II, UPDRS-IV, doses of l-DOPA equivalents) suggest a possible benefit for patients treated with nicotine, which should be confirmed in larger double blind, placebo-controlled studies.

Usefulness of T2 ratio in the diagnosis and prognosis of cardiac amyloidosis using cardiac MR imaging.

PURPOSE: To detect if a difference of T2 ratio, defined as the signal intensity (SI) of the myocardium divided by the SI of the skeletal muscle on T2-weigthed cardiac magnetic resonance (CMR) imaging, exists between patients with systemic amyloidosis, by comparison to control subjects. To determine if a relationship exists between T2 ratio and the overall mortality. MATERIALS AND METHODS: CMR imaging examinations of 73 consecutive patients (48 men, 25 women; mean age, 63 years±15[SD]) with amyloidosis and suspicion of CA and 27 control subjects were retrospectively analyzed after institutional review board approval. Final diagnosis of CA was retained in case of histological confirmation of CA, typical pattern of CA on imaging and/or positivity of 99Technetium-hydroxymethylene diphosphonate scintigraphy. Patients were divided in 2 groups according to the presence or the absence of CA. T2 ratios were calculated in patients with and those without CA and in control subjects with using analysis of variance. Prognostic value of T2 ratio was studied with a Kaplan-Meier curve. RESULTS: Thirty-five patients (51%) had CA and 33 (49%) were free from CA. T2 ratio was lower in patients with CA (1.18±0.29) than in patients without cardiac involvement (1.37±0.35) (P=0.03) and control subjects (1.45±0.24) (P=0.004). A T2 ratio of 1.36 was the best threshold value for predicting CA with a sensitivity of 63% and a specificity of 73%. Kaplan-Meier analysis showed a significant relationship between a shortened overall survival and a T2 ratio<1.36. CONCLUSION: Patients with CA exhibit lower T2 ratio on CMR imaging by comparison with patients free of CA and control subjects.

Prognostic value of baseline total metabolic tumor volume (TMTV0) measured on FDG-PET/CT in patients with peripheral T-cell lymphoma (PTCL).

BACKGROUND: Most peripheral T-cell lymphoma (PTCL) patients have a poor outcome and the identification of prognostic factors at diagnosis is needed. PATIENTS AND METHODS: The prognostic impact of total metabolic tumor volume (TMTV0), measured on baseline [(18)F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography, was evaluated in a retrospective study including 108 PTCL patients (27 PTCL not otherwise specified, 43 angioimmunoblastic T-cell lymphomas and 38 anaplastic large-cell lymphomas). All received anthracycline-based chemotherapy. TMTV0 was computed with the 41% maximum standardized uptake value threshold method and an optimal cut-off point for binary outcomes was determined and compared with others prognostic factors. RESULTS: With a median follow-up of 23 months, 2-year progression-free survival (PFS) was 49% and 2-year overall survival (OS) was 67%. High TMTV0 was significantly associated with a worse prognosis. At 2 years, PFS was 26% in patients with a high TMTV0 (>230 cm(3), n = 53) versus 71% for those with a low TMTV0, [P < 0.0001, hazard ratio (HR) = 4], whereas OS was 50% versus 80%, respectively, (P = 0.0005, HR = 3.1). In multivariate analysis, TMTV0 was the only significant independent parameter for both PFS and OS. TMTV0, combined with PIT, discriminated even better than TMTV0 alone, patients with an adverse outcome (TMTV0 >230 cm(3) and PIT >1, n = 33,) from those with good prognosis (TMTV0 ≤230 cm(3) and PIT ≤1, n = 40): 19% versus 73% 2-year PFS (P < 0.0001) and 43% versus 81% 2-year OS, respectively (P = 0.0002). Thirty-one patients (other TMTV0-PIT combinations) had an intermediate outcome, 50% 2-year PFS and 68% 2-year OS. CONCLUSION: TMTV0 appears as an independent predictor of PTCL outcome. Combined with PIT, it could identify different risk categories at diagnosis and warrants further validation as a prognostic marker.

Whole-body diffusion-weighted imaging in lymphoma.

The current evidence regarding the usefulness of whole-body diffusion-weighted magnetic resonance imaging (DWI) in lymphoma is reviewed. DWI is capable of combining anatomical and functional information and is becoming a valuable tool in oncology, in particular for staging purposes. DWI may prove to be a useful biomarker in clinical decision making for patients with lymphoma. Large-scaled prospective studies are needed to confirm these preliminary results.

Response assessment after an inductive CHOP or CHOP-like regimen with or without rituximab in 103 patients with diffuse large B-cell lymphoma: integrating 18fluorodeoxyglucose positron emission tomography to the International Workshop Criteria.

BACKGROUND: Revised response criteria for aggressive lymphomas have been proposed (Cheson, J Clin Oncol, 2007) stressing the role of (18)fluorodeoxyglucose-positron emission tomography (PET) in posttreatment evaluation. The value of PET after four cycles compared with the International Workshop Criteria (IWC) remains to be established. PATIENTS AND METHODS: In all, 103 patients with untreated diffuse large B-cell lymphoma were prospectively enrolled to evaluate the prognostic impact of PET after two and four cycles. RESULTS: Median age was 53 years (19-79), 68% male. The International Prognostic Index was low=22%, low-intermediate=19%, intermediate-high=33% and high risk=26%. Treatment consisted of cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) (30%) or dose-intensified CHOP (70%), with rituximab (49%) or without (51%). Ninety-nine patients were evaluated by PET and IWC at four cycles: 77 (78%) had a negative PET, while 22 (22%) remained positive. The 5-year event-free survival (EFS) was 36% for patients with a positive PET versus 80% with a negative examination, whatever the response [complete response (CR) versus partial response (PR)] according to IWC (P<0.0001). Positive PET patients had a 5-year EFS of 58% if in CR/CR unconfirmed by IWC and 0% if not (P<0.0001). The same observations could be made in patients treated with and without rituximab. CONCLUSION: The integration of PET in treatment evaluation offers a powerful tool to predict outcome.

Early detection of recurrence by 18FDG-PET in the follow-up of patients with colorectal cancer.

We assessed the potential benefits of including systematic 18fluorodeoxyglucose positron emission tomography (FDG-PET) for detecting tumour recurrence in a prospective randomised trial. Patients (N=130) who had undergone curative therapy were randomised to undergo either conventional (Con) or FDG-PET procedures during follow-up. The two groups were matched at baseline. Recurrence was confirmed histologically. 'Intention-to-treat' analysis revealed a recurrence in 46 patients (25 in the FDG-PET group, and 21 in the Con group; P=0.50), whereas per protocol analysis revealed a recurrence in 44 out of 125 patients (23 and 21, respectively; P=0.60). In another three cases, PET revealed unexpected tumours (one gastric GIST, two primary pulmonary cancers). Three false-positive cases of FDG-PET led to no beneficial procedures (two laparoscopies and one liver MRI that were normal). We failed to identify peritoneal carcinomatosis in two of the patients undergoing FDG-PET. The overall time in detecting a recurrence from the baseline was not significantly different in the two groups. However, recurrences were detected after a shorter time (12.1 vs 15.4 months; P=0.01) in the PET group, in which recurrences were also more frequently (10 vs two patients) cured by surgery (R0). Regular FDG-PET monitoring in the follow up of colorectal cancer patients may permit the earlier detection of recurrence, and influence therapy strategies.

[Interpretation of sentinel node identification in vulvar cancer]. / Interprétation de l'identification du ganglion sentinelle dans les cancers vulvaires.

OBJECTIVE: Sentinel node (SN) identification in vulvar carcinoma would avoid groin dissection and its complications in early stages, but we first have to validate the method, as an unrecognised node metastasis is detrimental to survival. PATIENTS AND METHODS: Since June 2002, 38 patients with T1 or T2 lesions underwent SN identification by radioactive tracer injection and scintigraphy with, on the following day, per operative use of a handheld probe +/- patent blue dye. In case of a midline lesion, a bilateral inguinal dissection was performed whatever the result of SN identification. SN free from disease were ultrastaged with immunohistochemistry. RESULTS: 1 or more SN were identified in 36 out of 38 patients. 64 groins were analysed, 15 with node metastases. In 9 out of these 15 cases the SN was metastatic, in 5 it had not been identified, and in 1 it was a false negative. In these last 6 cases, there were massively metastatic nodes in the groin. In 19 out of the 26 midline lesions the surgeon identified only unilateral SN. The side without SN contained metastatic nodes in 5 cases. DISCUSSION AND CONCLUSION: Failure in SN identification is sometimes related to a massively invaded node. This should be taken into account especially in the management of midline tumors where a seemingly unilateral drainage at scintigraphy warrants nevertheless a surgical assessment of the mute groin.

The structural brain correlates of cognitive deficits in adults with Klinefelter's syndrome.

CONTEXT: Adults with Klinefelter's syndrome (KS) are known to present disturbances of language skills and delayed learning abilities. OBJECTIVES: The aim of this study was to assess brain morphometry in KS and to correlate eventual volumetric changes with performance on neuropsychological tests. PATIENTS: Patients included 18 KS adults and 20 age-matched controls. METHODS: All participants underwent prospectively double-spin-echo brain magnetic resonance imaging and neuropsychological testing of verbal and nonverbal domains. On the axial stack of magnetic resonance imaging slices, regional brain volumes were measured either by automated segmentation (full brain, total cerebrospinal fluid, and ventricular volume) or manual drawing with help of a neuroanatomy atlas (frontal, temporal, and parietal lobes, gray matter component of the lobes, cerebellar hemispheres, and hippocampal complexes). RESULTS: KS patients performed significantly lower than controls on language-related tasks exploring verbal processing speed and verbal executive function. They were diagnosed with significant enlargement of ventricular volume and bilateral reduction of cerebellar hemispheres. Furthermore, after separation of participants according to handedness and after correction of regional brain volumes for atrophy, a significant reduction of left temporal lobe volume was found in KS compared with controls. Ventricular volume was inversely correlated with cognitive function, whereas left temporal lobe volume was positively correlated with language-related tasks. CONCLUSION: This study hypothesizes that supernumerary X-chromosome and/or congenital hypogonadism provoke structural alterations in the subcortical pathways involved in language processing, thus providing a neurobiological substrate for cognitive deficits in KS.

Functional breast imaging using the single photon technique.

Early diagnosis of carcinoma of the breast is currently attempted by mammography and physical examination which together have a sensitivity of 85%. Mammography has a positive predictive value of only 15 to 40 percent. The usefulness of scintimammography for the detection of carcinoma of the breast has been studied which demonstrated improved specificity compared to conventional mammography. In future, with the development or dedicated breast imager and new targeted radiopharmaceuticals, we can achieve detection of smaller than 1 cm carcinoma. This type of imaging enables us to detect cancer at its 'pre-anatomic' stage.

Myocardial tracking, a new method to calculate ejection fraction with gated SPECT: validation with (201)Tl versus planar angiography.

UNLABELLED: Left ventricular ejection fraction (LVEF) and viability are essential variables for the prognosis of myocardial infarction and can be measured simultaneously by (201)Tl gated SPECT; however, most algorithms tend to underestimate LVEF. This study aimed to evaluate a new myocardial tracking algorithm, MyoTrack (MTK), for automatic LVEF calculation. METHODS: A rest/redistribution (20 min/4 h) (201)Tl gated SPECT protocol followed immediately by a (99m)Tc equilibrium radionuclide angiography (ERNA) was performed in 75 patients with history of myocardial infarction. Quality of myocardial uptake was evaluated from count statistics and automatic quantification of defect sizes and severities (CardioMatch). LVEFs were calculated both with Germano's quantitative gated SPECT (QGS) algorithm and with MTK. Briefly, the originality of this algorithm resides in the unique end-diastole segmentation, matching to a template and motion field tracking throughout the cardiac cycle. RESULTS: ERNA LVEF averaged 33% +/- 14%. QGS significantly underestimated this value at 20 min (30% +/- 13%, P < 0.001) and at 4 h (30% +/- 13%, P < 0.0001). By contrast, MTK did not miscalculate LVEF at 20 min (34% +/- 14%, probability value was not significant) though a similar underestimation occurred at 4 h (31% +/- 13%, P < 0.02). Individual differences between early and late gated SPECT values and differences between gated SPECT and ERNA values did not correlate with the extension of perfusion defects, count statistics, or heart rate. CONCLUSION: MTK algorithm accurately calculates LVEF on early/high-count images compared with ERNA [corrected], even in patients with severe perfusion defects, but tends to underestimate LVEF on delayed/low-contrast images, as other algorithms do.

Thallium gated SPECT: relation between immediate post-stress evolution of ejection fraction and severity of perfusion pattern.

BACKGROUND AND AIMS: A significant decrease of left ventricular ejection fraction (LVEF) at stress has been reported with 99Tc(m) gated single-photon emission computed tomography (gSPECT) in severe myocardial stunning up to 1 h after exercise. This study was designed to show whether 201Tl gSPECT can measure LVEF evolution from rest to stress in routine examination and give additional information to perfusion interpretation since acquisition starts immediately after stress test. METHODS: Post-exercise and rest 201Tl gSPECT were performed in 187 patients with suspected coronary artery disease. Myocardial perfusion was quantified by 20-segment analysis. Patients were divided into four groups according to their summed perfusion score, reversibility rate and electrocardiographic findings, i.e. in order of severity: I = normal perfusion, II = fixed defect owing to a myocardial infarction, III = full reversible ischaemia, and IV = partial reversible ischaemia. LVEF was calculated by Germano's automatic algorithm. RESULTS: Normal subjects (n = 29) and infarcted patients (n = 34) showed a significant LVEF increase between rest and stress, +7 +/- 9% and +5 +/- 7% respectively. In full reversible ischaemic patients (n = 46), stress LVEF showed no increase (+1 +/- 8%) and this group was statistically different from both group I and group II. Furthermore, when ischaemia was partially reversible (n = 31), LVEF decreased significantly (-3 +/- 8%), particularly when exercise tests were abnormal (-4 +/- 8%). Group IV was statistically different from groups I and II. CONCLUSIONS: Good agreement exists between the severity of ischaemic perfusion pattern and LVEF degradation at stress, which is consistent with previously published data using 99Tc(m) gSPECT. Additionally, the use of 201Tl for immediate post-exercise imaging allows the observation of a physiological LVEF increase in normal and infarcted patients.

Precision of magnetic resonance velocity and acceleration measurements: theoretical issues and phantom experiments.

Magnetic resonance (MR) sequences have been developed for acquiring multiple components of velocity and/or acceleration in a reasonable time and with a single acquisition. They have many parameters that influence the precision of measurements: NS, the number of flow-encoding steps; NEX, the number of signal accumulations; and ND, the number of dimensions. Our aims were to establish a general relationship revealing the precision of these measurements as a function of NS, ND, and NEX and to validate it by experiments using phantoms. Previous work on precision has been restricted to two-step (NS = 2) or 1D (ND = 1) MR velocity measurements. We describe a comprehensive approach that encompasses both multistep and multidimensional strategies. Our theoretical formula gives the precision of velocity and acceleration measurements. It was validated experimentally with measurements on a rotating disk phantom. This phantom was much easier to handle than fluid-based phantoms. It could be used to assess both velocity and acceleration sequences and provided accurate and precise assessments over a wide, adjustable range of values within a single experiment. Increasing each of the three parameters, NS, ND, and NEX, improves the precision but makes the acquisition time longer. However, if only one parameter is to be assessed, maximizing the number of steps (NS) is the most efficient way of improving the precision of measurements; if several parameters are of interest, they should be measured simultaneously. By contrast, increasing the number of signals accumulated (NEX) is the least efficient strategy.

Assessment of ejection fraction with Tl-201 gated SPECT in myocardial infarction: Precision in a rest-redistribution study and accuracy versus planar angiography.

BACKGROUND: Viability and left ventricular ejection fraction (LVEF) are essential measures for the assessment of myocardial infarction (MI). These 2 variables may be evaluated simultaneously by means of thallium-201 gated single photon emission computed tomography (SPECT); however, the precision and accuracy of LVEF measurements with this isotope remain controversial, particularly in cases of extended perfusion defects and poor count densities. METHODS AND RESULTS: Fifty patients with a history of MI underwent a 20-minute rest and a 4-hour redistribution Tl-201 gated SPECT viability protocol, immediately followed by a technetium-99m planar equilibrium radionuclide angiography (ERNA). On gated SPECT images, various count statistics were calculated, and perfusion was automatically quantified by means of CardioMatch, which provided both the size and severity of MI defects. Rest and redistribution LVEFs were determined from gated SPECT with Germano's algorithm, whereas LVEFs were calculated from ERNA using the manufacturer's software. Mean LVEF values calculated with rest gated SPECT, redistribution gated SPECT, and planar ERNA were 30% +/- 13%, 30% +/- 13% and 33% +/- 13%, respectively. Significant differences between repeated gated SPECT LVEFs were not shown by means of the paired t test. Correlation coefficients were high between 20-minute and 4-hour scans (r = 0.89) and between gated SPECT and ERNA (r = 0.88 and r = 0.92 at 20 minutes and 4 hours, respectively). Additionally, close agreement between gated SPECT and ERNA was shown by means of the Bland-Altman plot, despite an underestimation of 3 units. Finally, neither the technical conditions (count density, heart rate, lung uptake, etc) nor the perfusion alteration (size, severity, redistribution) appeared to interfere with the precision and accuracy of gated SPECT LVEF measurement. CONCLUSION: Tl-201 gated SPECT is a precise method for assessing LVEF within the same patient at 4-hour intervals, even with a substantial count decay, and it gives accurate results compared with planar ERNA, even in the case of large perfusion defects.

Changes in cerebral metabolism are detected prior to perfusion changes in early HIV-CMC: A coregistered (1)H MRS and SPECT study.

Human immunodeficiency virus-cognitive motor complex (HIV-CMC), a common complication of the acquired immunodeficiency syndrome (AIDS), is characterized by progressive cognitive impairment and motor dysfunction. Functional imaging methods, such as single-photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy ((1)H-MRS), have been applied to assess the severity of brain injury. However, it is unclear which of these two methods is more sensitive in detecting brain abnormalities in patients with early HIV-CMC. Twenty-four HIV-CMC patients were compared with 34 healthy subjects; each had quantitative SPECT ((133)Xenon-calibrated (99m)Tc-HMPAO) and quantitative (1)H-MRS. Both modalities were co-registered in order to assess regional cerebral blood flow (rCBF) and metabolite concentrations within the same voxel of interest in four brain regions (midfrontal and midparietal gray matter, temporoparietal white matter, and basal ganglia). On SPECT, only the temporoparietal white matter showed a trend for decreased rCBF in HIV-CMC patients (-13%, P = 0.06). On MRS, HIV-CMC patients showed significantly reduced creatine concentration in the basal ganglia (-8%, P = 0.008), as well as increased myoinositol concentrations in the basal ganglia (+25%, P = 0.01) and the temporoparietal white matter (+18%, P = 0.08). There was no significant correlation between SPECT and MRS variables in the patients in any region. (1)H MRS showed abnormal neurochemistry in the basal ganglia, whereas rCBF on SPECT was normal in the same region. This finding suggests that metabolite concentrations on (1)H MRS are better surrogate markers than rCBF measurements with SPECT for the evaluation of brain injury in early HIV-CMC. J. Magn. Reson. Imaging 2000;12:859-865.

Optimization of aerosol deposition by pressure support in children with cystic fibrosis: an experimental and clinical study.

Nebulized aerosols are commonly used to deliver drugs into the lungs of patients with cystic fibrosis (CF). The aim of this study was to assess the effectiveness of pressure-support (PS) ventilation in increasing aerosol deposition within the lungs of children with CF. An in vitro study demonstrated the feasibility of coupling a breath-actuated nebulizer to a PS device. An in vivo study was done with 18 children (ages 6 to 21 yr) with clinically stable CF, each of whom underwent both a standard and a PS-driven ventilation scan (control session and PS session, respectively). In addition, a perfusion scan was used to determine lung outlines and to construct a geometric model for quantifying aerosol deposition by radioactivity counting in MBq. Homogeneity of nebulization was evaluated from the four first-order moments of aerosol distribution in the peripheral and central lung regions. The time-activity nebulization curve was linear in all patients, with higher slopes during the PS than during the control session (0.43 +/- 0.07 [mean +/- SD] MBq/min and 0.32 +/- 0.23 MBq/min, respectively; p < 0.018). Quantitatively, aerosol deposition was about 30% greater after the PS session (4.4 +/- 2.7 MBq) than after the control session (3.4 +/- 2.1 MBq; p < 0.05). Similarly, deposition efficacy (as a percentage of nebulizer output) was significantly better during the PS session than during the control session (15.3 +/- 8.3% versus 11.5 +/- 5.7%, p < 0.05). No differences in the regional deposition pattern or in homogeneity of uptake were observed. In conclusion, our data show that driving the delivery of a nebulized aerosol by noninvasive PS ventilation enhances total lung aerosol deposition without increasing particle impaction in the proximal airways.

Multidimensional MR mapping of multiple components of velocity and acceleration by fourier phase encoding with a small number of encoding steps.

Previous studies have shown that the multi-step approach of velocity or acceleration encoding is highly efficient in terms of the signal-to-noise ratio per unit time. This work describes a multidimensional extension of this method for simultaneously measuring multiple components of velocity and acceleration with a few encoding steps. N flow dimensions were encoded with an ND-matrix, obtained by combining the various flow-encoding gradients. The small matrix obtained with as few as two encoding steps can be extended by zero-filling in all N dimensions and using ND-Fourier transformation to obtain the maximum of the resulting peak in the ND-matrix, which gives simultaneously all the components of velocity and/or acceleration. The processing time was shortened by using a method of phase computation that gives the same precision as Fourier transformation, but is much faster. A rotating disk was used to show that the velocity-to-noise ratio increases with the number of dimensions acquired, demonstrating the efficiency of multidimensional flow measurements. The feasibility of the method is illustrated by 3D maps of the myocardium velocity, and 2D measurement of velocity and acceleration in the ascending aorta-both obtained by multidimensional phase encoding in volunteers.