Residual Opacity Research Articles

Nonopacification of Frontal and Parietal Branches After Middle Meningeal Artery Embolization: A Radiographic Benchmark

BackgroundMiddle meningeal artery embolization (MMAE) has revolutionized the armamentarium for chronic subdural hematoma (CSDH) treatment. Technical and angiographic benchmarks to guide procedural and clinical success are less well-established. MethodsA single-center database was reviewed to compare outcomes after standalone MMAE with and without resultant residual angiographic opacification of frontal and parietal (F/P) branches. Primary outcome was surgical rescue for CSDH progression. Secondary outcomes included the efficiency and accumulated efficacy of hematoma-resolution. Effect sizes were adjusted via multivariable regression. ResultsOf 147 standalone MMAE for CSDH, the overall rate of surgical rescue was 6.8%. Non-opacification of F/P branches via proximal MMA or meningo-ophthalmic anastomosis, was achieved after 83% of procedures and was associated with a 7-fold decreased rate of surgical rescue (3.3% vs. 24%, P=0.001). At 90-day follow-up, a higher rate of hematoma-resolution ≥ 50% was achieved if no residual opacification was identified (82% vs. 56%, P=0.03). The median time-to-50%-hematoma-resolution was 44 days for the no-residual group versus 71 days for the residual group (P<0.001). The unfavorable effects of residual opacification of F/P branches were verified in a multivariate analysis: a higher risk of surgical-rescue (adjusted OR 24.6; P=0.001) and poor hematoma resolution were both confirmed (adjusted HR 0.3; P=0.001). ConclusionMMAE with non-opacification of F/P branches was associated with augmented efficacy. Nuanced MMAE adequately tackling culprit dural feeders should be considered for more effective procedures.

Microsporidial keratoconjunctivitis - first outbreak in Japan.

Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial keratoconjunctivitis in Japan among healthy, immunocompetent soccer players from the same team during a 1-month period. This study is an observational case series. The medical records were analyzed for five cases with microsporidial keratoconjunctivitis who presented within September 2022. All five cases were males between 28 and 36 years old. These previously healthy individuals belonged to the same football team. Their eyes were considered susceptible to contaminated water or dirt from the turf at game and practice sites. All cases involved unilateral conjunctivitis, with scattered round white lesions that showed positive fluorescein staining in the corneal epithelium. All cases experienced diminution of vision in the affected eye. In three cases, direct smears showed spores of approximately 2-3μm in diameter. Polymerase chain reaction (PCR) analysis of corneal scrapes revealed partial amplification of microsporidial 18S ribosomal RNA gene in four cases. Sequences of PCR products from all four cases showed 100% identity with strains of Vittaforma corneae previously reported from an outbreak in Singapore. All cases were treated with topical therapy, including voriconazole, fluorometholone, and levofloxacin. Four eyes underwent corneal scraping. After treatment, all eyes healed without residual opacities. Only a few sporadic case reports of this disease have previously been reported in Japan. We detected V. corneae in our case series, representing what appears to be the first outbreak of microsporidial keratoconjunctivitis in Japan. Exposure to contaminated water or soil, in addition to inadequate sanitary facilities, represents a potential source of infection. Further investigations to clarify the characteristics of microsporidia seem warranted.

Chest CT in covid-19 pneumonia's follow-up: A 30 patients case series.

Lung abnormalities do not fully resolve in all Covid-19 survivors and may progress to fibrosis. Understanding post-COVID lung changes helps identify patients susceptible of post-COVID-19 sequelae. We analyzed scannographic residual lung abnormalities and the full resolution percentage on intermediate- and long-term follow-up (3 months or more). Data from 30 RT-PCR positive COVID-19 patients undergoing at least one follow-up chest CT at Ibn Sina Hospital, with a minimal time interval of 3 months between the RT-PCR and the CT performance were gathered retrospectively. The following elements were analyzed: (1) lung opacities, (2) distribution, (3) dominant lung opacity, (4) Sub-pleural bands, (5) Interlobular septal thickening, (6) Vascular dilatation, (7) Bronchiectasis, (8) Honey combing, (9) Architectural distortion, (10) mosaic attenuation, and (11) Additional findings: Enlarged lymph nodes, Pleural and Pericardial fluid. To evaluate the degree of lung opacification, a score founded on visual evaluation of the lung involvement's percentage was employed. Patients were then subdivided into two categories: (1) no residual opacities and (2) remaining pulmonary opacities. 30 patients were enrolled. The age ranged between 40 and 87 years. CT was indicated for symptoms or functional impairment. The time range between the positive RT-PCR and Follow-up CT varied between 3 and 12 months. CT severity score ranged between o and 23. Residual lung opacities were present in 24 cases (80%). The dominant lung opacities were Ground glass (46.7%), and linear/curvilinear opacities (23.3%). Signs of fibrosis were present in 9 patients (30%). CT abnormalities following Covid-19 pneumonia's prevalence varies based on the extent of the original lung affection and the time gap since the acute phase. Residual anomalies' effects on respiratory physiology, symptoms, and quality of living are unknown. Maintained monitoring of COVID-19 survivors with clinical examination, iterative pulmonary function tests, and HRCT is advised.

Il testo della Metafisica nell’«Aristotele di Vienna»

This article proposes a follow up of Fazzo’s contributions on the stemma codicum of Aristotle’s Metaphysics – including her Chora 2015 paper, its completion in the 2017 Revue d’Histoire des Textes and, most recently, a contribution on the text of Zeta 17 in Aristotelica 1 2022. All of these are summarized and framed here in the context of today’s lively debate. We then introduce the data of Marco Ghione’s collation and comparison of the readings of the two oldest manuscripts J and E : J, the Vind. phil. gr. 100, early 9th century – the so‑called “Aristotle of Vienna” – is thus extensively compared with E, Paris. gr. 1853, early 10th century, with selected reference to the earliest hands at work (J, J2, E1). Based on Paul Maas’ theory of errors, we are now in condition to face the crucial issue : does the latter depend on the former ? This helps resolving the one residual opacity or incertitude concerning the upper part of the Metaphysics’ stemma.

Results of the Preformed Physical Factors Application in the Rehabilitation Treatment of Corneal Ulcerative Defects

Currently, an infectious corneal ulcer, a defect in the corneal epithelium, remains one of the main causes of monocular blindness,which necessitates the development of new effective methods of treatment. Aim. To develop and evaluate the effectiveness of the technique for the complex application of preformed physical factors of local andsegmental action in patients with corneal ulcers. Material and methods. The study involved 85 patients with corneal ulcers aged 18 to 60 years divided into three groups. Patients ofthe control group (29 people) received the standard drug therapy, the comparison group (29 people) underwent a course of magnetophoresiswith solcoseryl on closed eyelids against the background of standard drug therapy, patients of the main group (27 people)received standard drug therapy, magnetophoresis and low-frequency electrostatic fields on the collar area. All patients were evaluatedfor visual acuity, the size of the ulcer and the area of stromal infiltration. The subjective severity of pain syndrome (VAS scale),psychoemotional state (SAN test) were assessed. Statistical analysis of the data was performed using SPSS Statistics v.25. Results. Immediately after treatment, the use of preformed physical factors made it possible to shorten the period of the ulcer epithelializationand suppression of the inflammatory reaction in the cornea, which significantly improved the clinical and functionalparameters of the eye, as well as considerably reduced the severity of pain syndrome in comparison with standard drug treatment. Conclusion. In the long-term period, the use of preformed physical factors contributed to a significant decrease in the size of thecorneal infiltration area (residual opacities) and an improvement in the quality of life of patients according to the General MentalWellbeing scale, which exceeded the effectiveness of standard drug therapy, while the combined use of a low-frequency electrostaticfield and magnetophoresis allowed to noticeably improve the indicators of visual acuity in comparison with standard drug therapyand isolated use of magnetophoresis.

Abstract 17230: Transcatheter Leak Occlusion With Endovascular Coils Following Left Atrial Appendage Closure

Introduction: The Transcatheter Leak Closure With Detachable Coils Following Incomplete Left Atrial Appendage Closure Procedures (TREASURE) is a prospective, nonrandomized, single-center study. This study was undertaken to investigate the efficacy of transcatheter leak closure with endovascular coils in patient with incomplete percutaneous/epicardial left atrial appendage (LAA) closure procedures and high thromboembolic (TE)- and bleeding-risk. Hypothesis: We report the efficacy of transcatheter leak closure with endovascular coils in patients with incomplete LAA closure. Methods: Sixty-five consecutive patients with a clinically relevant residual leak (mean age: 72±8 years; 73.8% males; CHA 2 DS 2 -VASc: 4.7±1.1; HAS-BLED: 3.7±0.7) underwent percutaneous closure of the LAA patency via embolization coils. Trans-esophageal echocardiography (TEE) was performed at 60±15 days post-procedure. Results: LAA closure had been previously attempted with a Watchman device in 62 patients, and a LARIAT in 3. Baseline TEE documented a moderate or severe leak in 14 (21.5%) and 51 (78.5%) patients, respectively. Procedure and fluoroscopy times were 69±37min and 22±15min, respectively; the mean volume of iodinated contrast medium used was 82±43mL. Coil deployment was successful in all cases [median n. of coils attempted: 3 (IQR:2-5); median n. of coils deployed: 3 (IQR: 2-4)]. The overall complication rate was 3.1% (1 pericardial tamponade, 1 pericardial effusion). Peri-procedural angiographic and TEE outcomes demonstrated complete obliteration or a negligible residual opacification with a trivial residual jet in 62 cases (95.4%), and a partial occlusion with moderate residual jet in 3 (6.4%). Follow-up TEE after 67±12 days revealed complete LAA sealing or a negligible residual leak in 63 cases (96.9%). Coil deployment led to an average reduction of 90.1% in leak size (p&lt;0.001). After an overall follow-up of 17±4 months, no TE events were documented; 3 patients died from non-cardiovascular and one from cardiovascular causes (heart failure). Conclusions: Transcatheter LAA leak occlusion via endovascular coils appears to be a safe, effective, and promising approach in high TE-risk patients with incomplete LAA closure.

The 13CO2 absorption spectrum by CRDS near 1.74 µm

The 1.74 µm spectral region corresponds to a very weak absorption interval of carbon dioxide (or “transparency window”) of particular importance to sound the deep atmosphere and the surface of Venus. In the present work, we extend the characterization of this spectral interval by the study of the 13CO2 isotopologues by high sensitivity cavity ring down spectroscopy (CRDS) with a highly enriched 13C sample. Indeed, in spite of their low natural abundances, the 13C minor isotopologues (in particular 16O13C18O with natural abundance less than 4.5 × 10−5) contribute importantly to the small residual opacity. In the studied 5694–5851 cm−1 spectral interval about 980 lines with intensity values as low as a few 10−30 cm/molecule at 296 K were detected. On the basis of the predictions of effective Hamiltonian models, the measured CO2 transitions were assigned to six isotopologues: 12C16O2, 13C16O2, 16O12C18O, 16O13C18O, 16O13C17O and 13C18O2. A total of 20 bands were assigned to the 13C isotopologues. Six of them are newly reported while the set of observed rotational transitions is enlarged for the others. The spectroscopic parameters of nineteen 13CO2 bands are determined from standard band-by-band analysis (typical rms deviations of the line positions are 8 × 10−4 cm−1).The new data show an overall good agreement with the Carbon Dioxide Spectroscopic Databank (CDSD-296), HITRAN2016 database and ab initio CO2 line lists. The previously identified issue related to the mixing of line intensities with CDSD or ab initio origins in the HITRAN database is illustrated by the 41104-00001 band of 13C16O2. A general discussion of the bands affected by this issue in the HITRAN2016 list is included.

A Faith Built on Awe

Abstract Reframing atheism as a set of positive beliefs, I describe a way of living in the world in which atheism requires faith, defined as a commitment to beliefs that are both logically and empirically not subject to proof. Faithful atheists have faith in and take spiritual nourishment from being in the presence of a world which is awesome and wonderful both in that it is immediately available and that it is and will always remain at least partly opaque to understanding. They do so without positing a God or inflating the reach of reason. Their way of living is characterized by “sensational presence” (full attention to and staying with a present moment) and the courage to accept that their access and understanding whether in relation to other people, other animals, and nature more generally, is always limited. This inherent residual opacity grounds their respect and sense of mystery in each of these realms.

Imaging findings of diabetes on post-mortem CT

Abstract Diabetes mellitus is a chronic, metabolic disease primarily defined by elevated levels of blood glucose. Long term effects of micro- and macrovascular damage may affect the cardio-vascular system, genitourinary tract, abdominal organs, nervous system, and musculoskeletal system. Diabetes can be challenging to detect at autopsy and if investigators are unaware of the medical history at the time of the autopsy the diagnosis may be missed. Postmortem computed tomography (PMCT) is able to detect a number of radiologic findings associated with diabetes, including obese stature, atherosclerosis, left ventricular hypertrophy, renal atrophy, residual opacification of the urinary tract from clinical CT, bladder over-distension, and calcification of the vas deferens. Signs of diabetes on pre-autopsy PMCT may direct additional investigations to confirm the diagnosis and account for the potential impact of diabetes on the cause of death.

Preliminary results on the composition of Jupiter's troposphere in hot spot regions from the JIRAM/Juno instrument

AbstractThe Jupiter InfraRed Auroral Mapper (JIRAM) instrument on board the Juno spacecraft performed observations of two bright Jupiter hot spots around the time of the first Juno pericenter passage on 27 August 2016. The spectra acquired in the 4–5 µm spectral range were analyzed to infer the residual opacities of the uppermost cloud deck as well as the mean mixing ratios of water, ammonia, and phosphine at the approximate level of few bars. Our results support the current view of hot spots as regions of prevailing descending vertical motions in the atmosphere but extend this view suggesting that upwelling may occur at the southern boundaries of these structures. Comparison with the global ammonia abundance measured by Juno Microwave Radiometer suggests also that hot spots may represent sites of local enrichment of this gas. JIRAM also identifies similar spatial patterns in water and phosphine contents in the two hot spots.

Primary posterior capsulotomy in adults with posterior capsule opacification

To evaluate the efficacy and safety of primary posterior continuous curvilinear capsulorhexis (PCCC) in adult patients with cataract. Zagazig University Hospital, Ash-Sharkya, Egypt. Prospective nonrandomized case series. This study comprised patients with senile cataract who had phacoemulsification. All patients had a dense posterior capsule opacification (PCO) discovered intraoperatively. Primary PCCC was performed to remove the residual opacification after posterior capsule polishing. All patients were followed for 3months postoperatively. The outcome measures were corrected distance visual acuity (CDVA), macular edema detected by optical coherence tomography, and the occurrence of intraoperative or postoperative complications. Twenty-five eyes of 25 cataract patients had phacoemulsification. The mean age was 61.9years±7.5 (SD). The mean CDVA preoperatively was 0.14±0.08 and postoperatively it was 0.86±0.15 at 1week, 0.93±0.08 at 1month, and 0.94±0.08 at 3months (P=.001). The mean central macular thickness was 313.16±8.39μm preoperatively and 315.04±10.6μm, 319.88±26.06μm, and 316.4±13.7μm at 1week, 1month, and 3months postoperatively, respectively (P=.35). Posterior capsule opening contracture occurred in 1 eye (4%), although it did not affect the patient's vision. Intraoperative posterior capsule extension occurred in 1 eye (4%). No serious complications, such as retinal detachment or endophthalmitis, were detected in any patient. Cataract surgery with primary PCCC was a safe procedure to treat residual PCO in adults and had a low rate of complications. Neither author has a financial or proprietary interest in any material or method mentioned.

Intrapleural Fibrinolytic Therapy for Residual Coagulated Hemothorax After Lung Surgery.

Many studies have described the use of intrapleural fibrinolytics for the treatment of complex pleural processes and traumatic hemothorax, but data are scarce regarding their use for hemothorax after lung surgery. To evaluate the utility of intrapleural fibrinolytic therapy with urokinase for residual coagulated hemothorax (blood clot accumulation in the pleural cavity) after lung surgery. From July 2009 to November 2013, 46 patients (33 males; mean age, 56.9 ± 10.7 years) were treated with intrapleural urokinase (250,000 IU per dose) for residual hemothorax after lung surgery. Complete response was defined as clinical improvement with complete drainage of the retained collection shown by chest X-ray, and partial response as substantial resolution with minimal residual opacity (<25 % of the thorax). Follow-up was at least 30 days. The procedure was successful in 42 patients (91.3 %), with complete response observed in 35/46 patients (76.1 %) and partial response in 7/46 (15.2 %). These 42 patients did not require re-intervention for fluid accumulation in the pleural cavity. Treatment failed in 4 patients (8.7 %): one developed bronchopleural fistula that later resolved spontaneously and three (6.5 %) required thoracoscopic drainage for pleural cavity fluid accumulation and lung collapse. No patient required thoracotomy for total decortication. Intrapleural urokinase administration was not associated with serious adverse events, including bleeding complications or allergic reactions. Intrapleural fibrinolytic agents should be considered a useful therapeutic option for the treatment of postoperative residual hemothorax. This method appears to be safe and effective in >90 % of patients with postoperative hemothorax.

Financial Opacity and Firm Performance: The Readability of REIT Annual Reports

We examine the capital market pricing implications of firm disclosure opacity as measured by the linguistic readability of REIT annual reports. The SEC has expressed concern that firms selectively manage the transparency of disclosures in order to hide adverse information. After controlling for other non-experimental factors that influence the readability of REIT financial statements, we find (1) financial opacity is negatively related to reported firm performance, and (2) the residual opacity that remains after controlling for other determinants of annual report readability has incremental explanatory power for returns beyond the Fama and French (1992, 1993) risk factors. The opacity risk-return premium persists after controlling for a (heretofore undocumented) stark monotonic decrease in annual report readability following the Sarbanes-Oxley Act of 2002.

Nebular emission-line profiles of Type Ib/c supernovae - probing the ejecta asphericity

In order to assess qualitatively the ejecta geometry of stripped-envelope core-collapse supernovae, we investigate 98 late-time spectra of 39 objects, many of them previously unpublished. We perform a Gauss-fitting of the [O I] 6300, 6364 feature in all spectra, with the position, full width at half maximum (FWHM) and intensity of the 6300 Gaussian as free parameters, and the 6364 Gaussian added appropriately to account for the doublet nature of the [O I] feature. On the basis of the best-fit parameters, the objects are organised into morphological classes, and we conclude that at least half of all Type Ib/c supernovae must be aspherical. Bipolar jet-models do not seem to be universally applicable, as we find too few symmetric double-peaked [O I] profiles. In some objects the [O I] line exhibits a variety of shifted secondary peaks or shoulders, interpreted as blobs of matter ejected at high velocity and possibly accompanied by neutron-star kicks to assure momentum conservation. At phases earlier than ~200d, a systematic blueshift of the [O I] 6300, 6364 line centroids can be discerned. Residual opacity provides the most convincing explanation of this phenomenon, photons emitted on the rear side of the SN being scattered or absorbed on their way through the ejecta. Once modified to account for the doublet nature of the oxygen feature, the profile of Mg I] 4571 at sufficiently late phases generally resembles that of [O I] 6300, 6364, suggesting negligible contamination from other lines and confirming that O and Mg are similarly distributed within the ejecta.

Whole bowel irrigation (WBI) in acute iron poisoning — case report

Abstract Objective: In theory, WBI (whole bowel irrigation) is indicated in iron poisoning, but the existing data are still insufficient to support or exclude its efficacy. Case report: A 46 year-old female admitted to the Toxicology Department due to suicidal ingestion of 5000 miligrams of elemental iron (57 mg/kg) in sustained-release preparation. WBI was instituted at 2 hours after ingestion, because abdominal X-ray showed mass of tablet material inside stomach and past pylorus. After 3-hour WBI subsequent X-ray revealed residual opacities in small intestine. Levels of serum iron were increasing 289 μg/dL on admission, (1,5 h post ingestion) 408 μg/dL (6 h after ingestion), 424 μg/dL (after 12 h). WBI was continued within 7 hours, until there was no radiographic evidence of toxin remaining in the gastrointestinal tract and clear rectal effluent was apparent. Subsequent serial serum iron concentrations were as follows: 389 μg/dL (after 14 h), 239 μg/dL (after 21 h), 119 μg/dL (after 36 h). Since the patient was asymptomatic did not undergo deferoxamine therapy. Patient recovered without sequelae. Conclusion: WBI seems to be beneficial in early stage of iron intoxication ensuring rapid and effective cleansing of gut, and decreasing toxin absorption. Authors believe that the use of early WBI allows to provide supportive care and avoid deferoxamine treatment.

Incidence of and risk factors for residual posterior capsule opacification after cataract surgery

Purpose: To evaluate the incidence of and determine the risk factors for residual posterior capsule opacification (PCO). Setting: University of New Mexico Health Sciences Center and the Veterans Administration Medical Center, Albuquerque, New Mexico, USA. Methods: This study evaluated 194 uneventful cataract surgeries. Immature cataracts were graded for nuclear sclerosis (NS), posterior subcapsular cataract (PSC), and anterior cortical spokes on a 1 to 4 scale. Preoperative Snellen best corrected visual acuity was converted to the logMAR scale. The posterior capsule was examined after polishing and was classified as clear or as having residual opacity. Those with residual capsule opacity were evaluated 6 weeks postoperatively for the presence of visually significant PCO. Results: The incidence of residual capsule opacity was 23% (44 eyes). Seven (54%) of 13 eyes with white mature cataract had residual capsule opacity. In contrast, 37 (20%) of 181 eyes with immature cataract had residual capsule opacity ( P = .01). In eyes with immature cataract, the mean preoperative logMAR acuity was +1.14 ± 0.60 (SD) in the residual capsule opacity group and +0.73 ± 0.46 in the clear group ( P<.001). In eyes with immature cataract, the adjusted odds ratio for each increasing grade of NS was 2.3 and of PSC, 1.8 ( P = .002 and P<.001, respectively). Eleven percent (5 eyes) of residual capsule opacities resulted in visually significant PCO 6 weeks postoperatively. All 5 opacities were centrally located at surgery. Conclusions: Results indicate that aggressive polishing of peripheral or adherent residual capsule opacities is not advisable as only 5 eyes with central residual capsule opacities developed visually significant PCO.

Severe acute respiratory syndrome: temporal lung changes at thin-section CT in 30 patients.

To evaluate lung abnormalities on serial thin-section computed tomographic (CT) scans in patients with severe acute respiratory syndrome (SARS) during acute and convalescent periods. Serial thin-section CT scans in 30 patients (17 men, aged 42.5 years +/- 12.2 [SD]) with SARS were reviewed by two radiologists together for predominant patterns of lung abnormalities: ground-glass opacities, ground-glass opacities with superimposed linear opacities, consolidation, reticular pattern, and mixed pattern (consolidation, ground-glass opacities, and reticular pattern). Scans were classified according to duration in weeks after symptom onset. Longitudinal changes of specific abnormalities were documented in 17 patients with serial scans obtained during 3 weeks. Each lung was divided into three zones; each zone was evaluated for percentage of lung involvement. Summation of scores from all six lung zones provided overall CT score (maximal CT score, 24). Median CT scores increased from 1 in the 1st week to 12.5 in the 2nd week. Ground-glass opacities with or without smooth interlobular septal thickening and consolidation were predominant patterns found during the 1st week. Ground-glass opacities with superimposed irregular reticular opacities, mixed pattern, and reticular opacities were noted from the 2nd week and peaked at or after the 4th week. After the 4th week, 12 (55%) of 22 patients had irregular linear opacities with or without associated ground-glass opacities and CT scores greater than 5; five of these patients had bronchial dilatation. When specific opacities were analyzed in 17 patients, consolidation generally resolved completely (n = 4) or to minimal residual opacities; six (55%) of 11 patients with ground-glass opacities had substantial residual disease (CT scores > 5) on final scans. There is a temporal pattern of lung abnormalities at thin-section CT in SARS. Predominant findings at presentation are ground-glass opacities and consolidation. Reticulation is evident after the 2nd week and persists in half of all patients evaluated after 4 weeks. Long-term follow-up is required to determine whether the reticulation represents irreversible fibrosis.

SARS: radiological features.

Air‐space disease is typical in severe acute respiratory syndrome (SARS) and may be indistinguishable from pneumonia of other causes. In the majority of patients, ground glass opacities on chest radiographs progress rapidly to focal, multifocal or diffuse consolidation. Unilateral involvement is common in the early acute phase, becoming bilateral at maximal lung involvement. Generally, radiographic opacities peak between 8 and 10 days after onset of illness, with radiographic scores reflecting temporal changes in clinical and laboratory parameters such as oxygen saturation (SaO2) and liver transaminases. Pleural effusions, cavitating consolidation and mediastinal lymphadenopathy are not typical radiographic features. Pneumomediastinum and pneumothoraces are complications that are associated with extensive disease, with or without assisted ventilation.The utility of high resolution computed tomography (HRCT) and CT scans lies in the confirmation of airspace opacities in cases with normal initial chest radiographs that have strong contact history and signs and symptoms highly suspicious of SARS during the outbreak, allowing early treatment and prompt isolation. The characteristic HRCT feature in the acute phase is ground‐glass opacities with smooth interlobular septal thickening, sometimes with consolidation in a subpleural location, which progress rapidly to involve other areas of the lungs. Temporal lung changes documented on HRCT suggest that some residual opacities found may not be reversible.

Tuberculous pleural effusion: new pulmonary lesions during treatment.

To evaluate patients who have a paradoxical response (development of new opacities) to treatment for tuberculous pleural effusion not related to acquired immunodeficiency syndrome. In 16 patients, follow-up chest radiographs (n = 16) and initial (n = 2) and follow-up (n = 9) computed tomographic (CT) scans of the chest were retrospectively reviewed by two radiologists. Patient records (n = 16) and results of percutaneous needle aspiration and/or biopsy (n = 6) were reviewed by one radiologist. Eighteen episodes of new lesion development were identified on radiographs in 16 patients. Each episode showed single (nine of 18 episodes, 50%) or multiple (nine of 18 episodes, 50%) nodules, most of which were in the peripheral lung (16 of 18 episodes, 89%) ipsilateral to the side of previous effusion (17 of 18 episodes, 94%). On CT scans, all lesions were peripheral pulmonary nodules, not round atelectasis. Needle aspiration and/or biopsy of the lesions showed findings consistent with tuberculosis in all six patients. Lesions usually evolved within 3 months after the start of medication (13 of 18 episodes) and finally disappeared (15 episodes) or left residual opacities (three episodes) 3-18 months later, with continuation of medication. New lung lesions that develop during medication for tuberculous pleural effusion should be considered a transient worsening that ultimately improves with continuation of medication.

Measurement of renal perfusion and blood flow with fast computed tomography.

Fast computed tomography (CT) is one of the few methods available to measure cortical and medullary renal blood flow (RBF) directly. Because these measurements are complicated by passage of the contrast medium into extravascular compartments, we used the residual opacity following the vascular blush as an index to account for extravascular iohexol. Kidneys of anesthetized dogs were examined in situ by fast CT following intra-aortic injections of iohexol. Perfusion was analyzed during a control period and three subsequent periods in which RBF was reduced by 10%, 30%, and 50%. Cortical microvascular distribution volume changed from 19.7 +/- 2.8% to 19.8 +/- 1.7%, 15.3 +/- 1.2%, and 9.9 +/- 1.7%, respectively, without significant alterations in cortical mean transit time. Microvascular distribution volume was divided by mean transit time to determine tissue perfusion. Cortical perfusion changed from 3.8 +/- 0.7 to 3.9 +/- 0.6, 3.1 +/- 0.5, and 2.2 +/- 0.5 mL.min-1.mL tissue-1. Total cortical blood flow (cortical perfusion multiplied by cortical volume) decreased from 164 +/- 32 to 159 +/- 31, 117 +/- 20, and 86 +/- 22 mL/min, respectively. Medullary microvascular distribution volume, mean transit time, perfusion, and total blood flow remained unchanged. Fast CT-determined total RBFs (cortex plus medulla) were similar to simultaneous electromagnetic flow measurements. These results indicate that renal regional perfusion is more dependent on the microvascular distribution volume than mean transit time and that variations in renal tissue perfusion with reduction of RBF are more apparent in the cortex than in the medulla.