Subsegmental Perfusion Defects Research Articles

230 ANOMALOUS ORIGIN OF LEFT CIRCUMFLEX ARTERY FROM RIGHT SINUS OF VALSALVA: A RARE CASE BUT WITH GREAT CLINICAL RELEVANCE

Abstract Introduction The anomalous connection of the left circumflex artery (LCx) to the right coronary artery (RCA) or sinus is the most frequent coronary artery (CA) anomaly. Among them, only those with an interarterial course are regarded as hidden conditions at risk of myocardial ischemia (MI) and sudden cardiac death (SCD). We report an uncommon of anomalous origin of LCx from the right sinus of Valsalva and a retroaortic path causing MI. Case presentation A 61-year-old man presented to the emergency department complaining palpitations and chest discomfort for an hour. He only had history of hypertension. Physical examination was unremarkable. The ECG demonstrated atrial flutter with a 2:1 conduction ratio and a ventricular rate of 157 bpm and ST segment depression in leads V4-6. Transthoracic echocardiography did not reveal segmental kinetic anomalies but a five-chamber apical view showed a “RAC sign”, typical of anomalous retroaortic course of the left coronary artery. The patient was treated with intravenous infusion of amiodarone. He restored sinus rhythm and symptoms regressed completely, but the ECG taken after conversion showed flattened T waves in leads V5-6 and negative T waves in I and aVL. Cardiac enzymes had transient increase. After the acute episode ended the patient underwent cardiac computed tomography angiography (CTA) with evidence of anomalous origin of LCx from the right sinus with a retroaortic course. A coronary angiography excluded obstructive atherosclerotic coronary lesions. Nuclear myocardial perfusion imaging revealed reversible small subsegmental perfusion defects in mid inferolateral wall and apical lateral wall. We established a medical treatment with beta-blocker. Discussion Our patient had anomalous connection of the LCx branch to the right sinus of Valsalva with a retroaortic course. Although this anomaly is usually considered benign, cases of association with SCD and MI have been reported. The factor responsible for this pathogenicity could be high orifice, ostial stenosis, slit-like/fish-mouth-shaped orifice and acute-angle take-off. As cardiac CTA did not reveal any of these characteristics, we hypothesized that the increased cardiac output and expansion of the great vessels during tachycardia could cause compression of the retroaortic segment or angling at its origin and generate ischemia. Repolarization abnormalities at ECG are well documented during supraventricular tachycardia as a response to pacing-induced stress. These changes are usually diffused and disappear after conversion to sinus rhythm. In this case they appeared hours later, accompanied by cardiac enzyme buildup. As the epicardial coronary arteries did not show any pathology, we suggest that the patient had transient ischemia due to LCx anomaly. We confirmed it by myocardial perfusion imaging. As for the management of this anomaly in adults, surgery is recommended as class IC in patients with typical angina symptoms who present with evidence of stress-induced myocardial ischemia in a matching territory or high-risk anatomy. Our patient has never had clear manifestations of angina. All these elements together with the age of our patient motivated us to use a conservative approach. Conclusions We report a case of anomalous origin of LCx from right sinus of Valsalva causing transient myocardial ischemia in a patient that has always been asymptomatic. This anomaly has been and continues to be considered benign, nevertheless we suggest to judge the clinical significance of this kind of CA anomaly on a case-by-case integrated approach.

Patterns of thromboembolic pulmonary vascular disease in COVID-19.

SARS-CoV-2 (COVID-19) is associated with increased thrombosis. Here, we demonstrate patterns of pulmonary vascular disease in COVID-19 including classical acute pulmonary embolism and subsegmental perfusion defects in the absence of acute pulmonary embolism suggestive of microvascular thrombosis.

Pulmonary Thromboembolism in Behcet’s Disease: A Case Report

Behcet’s disease is a vasculitis which presents as recurrent oral and genital aphthous ulceration, uveitis and skin lesions. Unlike other types of vasculitis, venous system involvement is a common manifestation of Behcet’s disease. Despite the high incidence of deep vein thrombosis in Behcet’s disease, pulmonary artery thromboembolism (PTE) is a rare complication. In this article, we report on a 44-year old man who experienced recurring painful oral ulcers, bilateral panuveitis, superficial phlebitis and positive pathergy which had led to a diagnosis of Behcet’s disease 12 years earlier. He developed sudden onset dyspnea, pleuritic chest pain and hemoptysis two days before admission. The patient had tachypnea and mild respiratory distress at the time of admission. CT angiography showed filling defects in the inter-lobar arteries of both lungs with sub-segmental consolidation. A lung perfusion scan showed multiple segmental and sub-segmental perfusion defects in both lungs which did not match the ventilation scan. A diagnosis of PTE was made and anticoagulation with enoxaparin and warfarin was begun. The tachypnea, chest pain and hemoptysis disappeared after three days and he was discharged after 10 days with warfarin. His disease was in complete remission at eight months after discharge.

CHRONIC POST-THROMBOEMBOLIC PULMONARY HYPERTENSION DEVELOPMENT IN A PATIENT WITH HEREDITARY THROMBOPHILIA: A CASE REPORT

Objective: to describe a clinical case of chronic post-thromboembolic pulmonary hypertension (CTEPH) development and progression in a patient with recurrent pulmonary thromboembolism (PTE) and hereditary thrombophilia. Materials and methods. Patient K., female, 50 years old, was hospitalized in the 1st therapeutic department of N.I. Pirogov First City Clinical Hospital with complaints of shortness of breath, occurring at rest and exacerbating after minimal physical activity, dry cough, chest heaviness, swelling of the lower extremities (mainly right one). The patient had a history of deep venous thrombosis (DVT) of the lower extremities, PTE, splenectomy, and long glucocorticosteroid drugs intake for thrombocytopenic purpura. The patient underwent different examinations in the hospital, including evaluation of laboratory tests in dynamics, echocardiography, contrast-enhanced multislice computed tomography of the pulmonary artery and its branches, perfusion lung scintigraphy, right heart catheterization. Results. After examination the patient was diagnosed with multiple segmental and subsegmental perfusion defects of both lungs; we also observed signs of pulmonary hypertension (PH) at echocardiography, proved by right heart catheterization. Also the patient was diagnosed with inherited thrombophilia. The patient was included in the register of PH-patients, thromboendarterectomy together with administration of special medications, approved for use in patients with pulmonary arterial hypertension (PAH-specific therapy) were recommended. Conclusion. This article describes the main features of CTEPH, its diagnostics and treatment in patients with CTEPH after PTE.

The Utility of Hybrid SPECT/CT Lung Perfusion Scintigraphy in Pulmonary Embolism Diagnosis

Background: Pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/Q) scintigraphy or pulmonary CT angiography. One of the imaging methods used in nuclear medicine is hybrid SPECT/CT scintigraphy. Objectives: The aim of this study was to evaluate the utility of SPECT/CT(Q) scintigraphy in the diagnosis of PE and to compare SPECT/CT(Q) with planar(Q) and SPECT(Q) methods. Methods: The study group consisted of 109 consecutive patients suspected of having PE referred for performing lung scintigraphy. The inclusion criteria were: performance of perfusion planar, SPECT and SPECT/CT scans; availability of clinical data covering a 6-month follow-up period, and D-dimer level testing. The number of eligible patients was 84. PE was reported in patients with at least 1 segmental or 2 subsegmental perfusion defects without parenchymal abnormalities on CT scans. PE was excluded when there was a normal perfusion pattern or perfusion defects were caused by lung parenchymal abnormalities or were not arranged in accordance with the pulmonary vasculature. Results: Twenty-six patients (31%) had a final diagnosis of PE. The sensitivity and specificity values of each method were as follows: planar(Q) 73 and 43%, SPECT(Q) 88 and 47% and SPECT/CT(Q) 100 and 83%. SPECT/CT(Q) yielded a significantly higher diagnostic accuracy than planar(Q) (p < 0.001) and SPECT(Q) (p < 0.001) scans. Conclusions: We conclude that hybrid SPECT/CT(Q) imaging has a high diagnostic efficacy in the diagnosis of PE. Lung perfusion scintigraphy performed with a hybrid SPECT/CT device has a significantly higher sensitivity and specificity than scanning performed with the planar or SPECT technique.

Multiples défauts segmentaires et sous-segmentaires de perfusion discordants avec une angiographie pulmonaire normale et une forte suspicion de maladie veino-occlusive pulmonaire

We report the case of a 55-year-old woman presenting stage-3-4 dyspnea over the last 5years with no other clinical symptoms. Pulmonary arterial hypertension (PAH) was evidenced by echocardiography. However, there was no argument for chronic thromboembolic disease during pulmonary angiography. The pulmonary scintigraphy showed homogeneous ventilation on both lung fields, with multiple bilateral segmental and subsegmental perfusion defects, however. These perfusion abnormalities with a normal pulmonary angiography led to the diagnosis of pulmonary veno-occlusive disease (PVOD) taking into account the clinical context, imaging findings, and laboratory and functional assessments. PVOD is a clinicopathological entity characterized by the occlusion or narrowing of the pulmonary veins and venules by fibrous tissue, leading to clinical manifestations that are, in many ways similar to PAH. PVOD remains poorly understood and it is difficult to diagnose and treat. However, PVOD needs to be known by clinicians and considered in the differential diagnosis of PAH.

Hypertension artérielle pulmonaire par embolisation de cellules tumorales

We report a 46-year-old woman with a metastatic breast cancer who developed a subacute pulmonary hypertension. The final diagnosis was microscopic pulmonary neoplastic emboli. She presented with the typical clinical picture of a pulmonary hypertension with a normal pulmonary angiographic computer tomography and multiple sub-segmental perfusion defects on radionuclide imaging. This serious condition must be known by physicians, because of an opportunity to obtain the diagnosis by the cytologic analysis of sampled microvascular blood obtained with a pulmonary artery catheterization. The prognosis is poor and there is no efficient therapy.

Lung Perfusion with Dual-energy Multidetector-row CT (MDCT): Feasibility for the Evaluation of Acute Pulmonary Embolism in 117 Consecutive Patients

To investigate the accuracy of dual-energy computed tomography in the depiction of perfusion defects in patients with acute pulmonary embolism (PE). One hundred seventeen consecutive patients with clinical suspicion of acute PE underwent dual-energy multidetector computed tomographic (CT) angiography of the chest with a standard injection protocol. Two radiologists evaluated, by consensus, the presence of endoluminal clots on (1) transverse "diagnostic" scans (contiguous 1-mm-thick averaged images from tubes A and B) and (2) lung perfusion scans. Seventeen patients showed CT features of acute PE, with the depiction of 75 clots within the lobar (n = 15), segmental (n = 43) and subsegmental (n = 17) pulmonary arteries. A total of 17 clots were identified as complete filling defects (ie, obstructive clots), located within segmental (12 of 17) and subsegmental (5 of 17) arteries. Fourteen of the 17 obstructive clots were seen with the concurrent presence of corresponding perfusion defects, whereas cardiac motion and/or contrast-induced artifacts precluded the confident recognition of perfusion abnormalities in the remaining two segments and one subsegment. Four subsegmental perfusion defects were depicted without the visualization of endoluminal thrombi within the corresponding arteries. Perfusion defects were identified beyond five nonobstructive clots. Simultaneous information on the presence of endoluminal thrombus and lung perfusion impairment can be obtained with dual-energy computed tomography.

High Definition Contrast-Enhanced MR Imaging in Paroxysmal Nocturnal Hemoglobinuria (PNH) Suggests a High Frequency of Subclinical Thrombosis.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder characterized by intravascular hemolysis and venous thrombosis. Thrombosis is the most feared complication in PNH and is reported to occur in >40% of patients. Proposed mechanisms of thrombosis include depletion of the coagulation regulator nitric oxide (NO) by intravascular hemolysis and increased sensitivity of PNH platelets to activation. The occurrence of subclinical thrombosis in PNH patients has not been previously studied using modern imaging techniques. In order to evaluate for subclincal thrombosis we evaluated PNH patients with a comprehensive state-of-the-art MRI protocol (which included the use of both blood pool and conventional Gadolinium based contrast agents) for the detection of subclinical thromboses and its sequelae. The detailed protocol consisted of:lung perfusion and pulmonary MRA,cardiac MR - including quantitative studies of both ventricles, right heart flow dynamics and delayed enhancement for the detection of left ventricular damage, andabdominal MR for the assessment of hepatic and portal venous systems and kidneys.10 PNH patients (median age 31.5 yrs) with large PNH clones but without previous clinical evidence of venous or arterial thrombosis underwent imaging. Five (50%) of the patients were on primary anticoagulant prophylaxis with warfarin. There was evidence of significant renal hemosiderosis, which was distributed throughout the cortices, in 8/10 patients. Two patients had small myocardial scars suggestive of previous unsuspected ischemic damage. Six patients had sub-segmental perfusion defects mainly distributed in the peripheries of the lung fields indicative of previous small pulmonary emboli. No such subclinical thromboses would be anticipated in an age-matched control population. 8 patients had mildly reduced right ventricular ejection fractions (mean 42.2±1.8%; normal range 48–63%). The plasma B-type natriuretic peptide (BNP) level was high in all 10 patients (median 29.4pmol/l; range 18.7–373.90; normal subjects 4.89±1.00pmol/l). BNP has been shown to increase in proportion to right ventricular dysfunction in pulmonary hypertenstion. No intraabdominal defects were identified with the current protocol. In summary, we identified abnormalities suggestive of previous subclinical thromboses in 6 of 10 hemolytic PNH patients by high-resolution MR imaging, including in patients on primary prophylaxis with warfarin. Effective prevention of thrombosis is an important aspect of the therapy in PNH.

Pulmonary perfusion in acute pulmonary embolism: agreement of MRI and SPECT for lobar, segmental and subsegmental perfusion defects

To assess prospectively the agreement of magnetic resonance (MR) pulmonary perfusion with single-photon emission computed tomography (SPECT) perfusion for perfusion defects down to the subsegmental level in patients with suspected pulmonary embolism (PE). In 41 patients with suspected PE, contrast-enhanced MR pulmonary perfusion (3D-FLASH, TR/TE 1.6/0.6 ms) was compared to SPECT perfusion on a per-examination basis as well as at the lobar, segmental, and subsegmental level. The MRI protocol was completed in all patients, and mean examination time was 3 min 56 s. MR perfusion showed a very high agreement with SPECT (kappa value per examination 0.98, and 0.98, 0.83, and 0.69 for lobar, segmental, and subsegmental perfusion defects, respectively). Of 15 patients with PE, MR perfusion detected 14 cases. The very high agreement of MR perfusion with SPECT perfusion enables the detection of subtle findings in suspected PE.

Chronic Thromboembolic Pulmonary Hypertension

Since the last World Symposium on Pulmonary Hypertension in 2008, we have witnessed numerous and exciting developments in chronic thromboembolic pulmonary hypertension (CTEPH). Emerging clinical data and advances in technology have led to reinforcing and updated guidance on diagnostic approaches to pulmonary hypertension, guidelines that we hope will lead to better recognition and more timely diagnosis of CTEPH. We have new data on treatment practices across international boundaries as well as long-term outcomes for CTEPH patients treated with or without pulmonary endarterectomy. Furthermore, we have expanded data on alternative treatment options for select CTEPH patients, including data from multiple clinical trials of medical therapy, including 1 recent pivotal trial, and compelling case series of percutaneous pulmonary angioplasty. Lastly, we have garnered more experience, and on a larger international scale, with pulmonary endarterectomy, which is the treatment of choice for operable CTEPH. This report overviews and highlights these important interval developments as deliberated among our task force of CTEPH experts and presented at the 2013 World Symposium on Pulmonary Hypertension in Nice, France.

Diagnosis and management of subsegmental pulmonary embolism.

Although the advent of multi-detector row computed tomography (CT) has enabled better visualization of subsegmental pulmonary (SSP) arteries, SSP embolism is of uncertain clinical significance. We aimed at answering the following questions: Is spiral CT an accurate method to detect SSP embolism? How are subsegmental perfusion defects managed in outcome studies including spiral CT? What are the main characteristics and outcomes of patients in whom CT detects isolated subsegmental defects? We performed a Medline search on July 1, 2004, using the keywords 'pulmonary embolism' and 'computed tomography'. We limited our search to English language prospective studies comparing CT to pulmonary angiography, and to prospective outcome studies including CT in a diagnostic strategy, with at least a 3-month follow-up. Fourteen studies comparing CT to pulmonary angiography, and five prospective management studies using CT were retrieved. The sensitivity of single-detector CT for detecting subsegmental defects compared with pulmonary angiography was low (25%). The proportion of isolated SSP images was significantly higher in management studies using multi-detector CT (17 of 770 scans, 2.2%) compared with those using single-detector CT (22 of 2232, 1.0%; P = 0.01). No straightforward attitude regarding anticoagulation therapy for isolated subsegmental defects emerged from the available literature. Finally, important clinical differences were found between patients having subsegmental and segmental or more proximal defects. These findings underline the uncertainty regarding the clinical significance of SSP embolism, and the management of patients with such findings.

Pulmonary embolism associated with canine total hip replacement.

To determine by pulmonary perfusion scans and ultrasonography if embolemia occurs during total hip replacement (THR) surgery in dogs. Prospective clinical study. Forty client-owned dogs that had THR surgery. Thoracic radiographs were taken immediately after THR and immediately after completion of (99m)Tc-MAA lung scans. Scintigraphy was performed in 28 dogs, 48 hours after THR. Intraoperative ultrasonography (intercostal or transesophageal) was performed in another 12 dogs that had THR. The right atrium and ventricle and pulmonary outflow tract were observed during and for 5 to 8 minutes after femoral component insertion into medullary canals prepared by reaming, and lavage and aspiration of debris before filling with polymethylmethacrylate in dough stage. A modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) classification system was used to evaluate lung scans. No pulmonary radiographic abnormalities were identified. Segmental and subsegmental perfusion defects occurred in 23 (82%) dogs and were classified as severe in 9 (32%) dogs, moderate in 11, and mild in 3. There was no particular lobe predilection. Patchy mulberry-appearing defects, indicative of fat embolism, were most common. Embolemia was observed by ultrasound in 10 dogs. Variable-sized particles occurred in 8 dogs, particles and bubbles in 2 dogs, and no emboli were observed in 2 dogs. Embolemia was observed within 10 seconds after femoral stem insertion and lasted < 1 minute. Pneumoemboli remained in the right atrium for > 8 minutes before dislodgement. Embolemia of either air, particles, or both occurs in most dogs during THR surgery. Most dogs seemingly spontaneously recover from pulmonary embolism that occurs during THR. The risk of clinical complications from this pulmonary embolism should be taken seriously, even though the exact morbidity and mortality rates are unknown.

Diagnosis of pulmonary embolism with spiral CT as a second procedure following scintigraphy.

Our objective was to evaluate, in a routine clinical setting, the role of spiral CT as a second procedure in patients with clinically suspected pulmonary embolism (PE) and abnormal perfusion scan. We prospectively studied the role of spiral CT in 279 patients suspected of PE. All patients started their diagnostic algorithm with chest radiographs and perfusion scintigraphy. Depending on the results of perfusion scintigraphy, patients proceeded to subsequent levels in the algorithm: stop if perfusion scintigraphy was normal; CT and pulmonary angiography if subsegmental perfusion defects were seen; ventilation scintigraphy followed by CT when segmental perfusion defects were seen; and pulmonary angiography in this last group when results of ventilation/perfusion scintigraphy and CT were incongruent. Reference diagnosis was based on normal perfusion scintigraphy, high probability perfusion/ventilation scintigraphy in combination with abnormal CT, or pulmonary angiography. If PE was present, the largest involved branch was noted on pulmonary angiography, or on spiral CT scan in case of a high-probability ventilation/perfusion scan and a positive CT scan. A distinction was made between embolism in a segmental branch or larger, or subsegmental embolism. Two hundred seventy-nine patients had abnormal scintigraphy. In 27 patients spiral CT and/or pulmonary angiography were non-diagnostic and these were excluded for image analysis. Using spiral CT we correctly identified 117 of 135 patients with PE, and 106 of 117 patients without PE. Sensitivity and specificity was therefore 87 and 91%, respectively. Prevalence of PE was 53%. Positive and negative predictive values were, respectively, 91 and 86%. In the high-probability group, sensitivity and specificity increased to 97 and 100%, respectively, with a prevalence of 90%. In the non-high probability-group sensitivity and specificity decreased to 61 and 89%, respectively, with a prevalence of 25%. In a routine clinical setting single-detector spiral CT technology has limited value as a second diagnostic test because of low added value in patients with a high-probability lung scan and low sensitivity in patients with non-high-probability lung scan result.

Ventilation-perfusion lung scan for the detection of pulmonary involvement in Takayasu's arteritis.

The aim of study was to analyse ventilation and perfusion (V/Q) lung scan findings in a series of Italian patients with Takayasu's arteritis. Eighteen consecutive patients underwent V/Q lung planar scintigraphy and single-photon emission tomography (SPET). Before perfusion scan acquisition was started, a first-pass study with (99m)Tc-macroaggregates of albumin was performed to assess the right ventricular ejection fraction (RVEF). All patients had normal chest X-rays and were symptom free at the time of the investigation. They also underwent echocardiography to evaluate pulmonary artery pressure and in 13 patients respiratory function tests were performed. In four patients, perfusion lung scan was repeated after 1 year. In 10/18 patients (55.5%), 43 unmatched lobar, segmental or subsegmental perfusion defects were found on planar images; ventilation scintigraphy was normal in all cases. On SPET images, 55 defects were found; no defects were found with SPET in the remaining patients who had normal planar images. All patients had normal RVEF and 5/13 patients had mild restrictive-obstructive lung disease. The pulmonary artery pressure was increased in two patients with perfusion defects. In the four patients who had repeat scintigraphy, all defects remained unchanged. The prevalence of lung perfusion abnormalities observed in Italian patients with Takayasu's arteritis is within the range of values reported in other countries, and V/Q planar scintigraphy is sufficient for the screening of patients.

A survey of the diagnostic and therapeutic management of patients with suspected pulmonary embolism in the Netherlands.

Pulmonary embolism (PE) remains a complex diagnostic problem. Many diagnostic modalities are available. Several published guidelines have failed to yield a uniform approach. We have assessed the current diagnostic and therapeutic management of patients with clinically suspected PE in the Netherlands. A questionnaire was sent to internists and pulmonologists, who were then asked to detail their diagnostic and therapeutic management in their last patient seen with suspected PE. 1571 questionnaires were sent out (response rate 64%). 95% of the patients with suspected PE underwent a perfusion scan (in 91% within 24 h). 1.6% of the respondents had no available perfusion scan facility. Of those who underwent a perfusion scan, 62% had ventilation scan (66% with segmental defects, 80% with subsegmental defects, 27% with a normal perfusion scan). Tests for deep vein thrombosis were performed in 58% of the patients and pulmonary angiography was carried out in 6.1%. Anticoagulant treatment was instituted in 73.2% of all patients. The perfusion lung scan is appropriately used as the initial step in the diagnostic workup of patients with suspected PE. Ventilation scanning is overused in patients with subsegmental perfusion defects and normal scan results, whereas it is underused in patients with segmental defects. Additional ventilation scan results had a limited influence on treatment decisions. There is still considerable overtreatment of patients with suspected PE.

Correlation of perfusion abnormalities on CTAP and immediate postintravenous gadolinium-enhanced gradient echo MRI.

The purpose of this study was to evaluate patients with wedge-shaped perfusion defects seen on spiral CT arterial portography for the presence of transient increased wedge-shaped enhancement on dynamic gadolinium-enhanced gradient echo MR images. Nineteen patients underwent CTAP and MRI within a 2-week interval. All patients with wedge-shaped perfusion defects on CT arterial portography were evaluated in a separate review session for the presence of transient increased segmental hepatic enhancement on dynamic gadolinium-enhanced spoiled gradient echo (SGE) MR images. Eight patients were identified to have subsegmental, segmental, or lobar wedge-shaped perfusion defects by CT arterial portography. In 8/8 patients, there was transient wedge-shaped increased hepatic enhancement on MR images which corresponded to the perfusion defects identified on CT arterial portography. Transient increased enhancement on MR images was observed on immediate postgadolinium images as high-signal intensity of the involved subsegment, segment, or lobe. This relatively high-signal area faded to near isointensity in all cases on images obtained at 45 s. Wedge-shaped perfusion defects demonstrated by CT arterial portography corresponded to wedge-shaped increased hepatic enhancement following gadolinium administration on SGE MR images.