Cine MRI in the Evaluation of Pulmonary Arteriovenous Malformations.

We present findings on cine magnetic resonance imaging (MRI) using steady-state free precession (SSFP) pulse sequences in a patient with pulmonary arteriovenous malformation (PAVM). The technique has the advantage of demonstrating the pulsation of lesions during the cardiac cycle on cine images. It may not replace but may complement other MRI sequences in the characterization of pulmonary lesions in selected cases. To our knowledge, no prior video of cine images of PAVM has been provided in the literature.

Dual-Energy Imaging of the Chest.

Dual-energy computed tomography (DECT) is a contemporary development by which the tissue can be characterized beyond conventional computed tomography. It improves tissue differentiation by exploiting the X-ray absorptive property of the tissues. Although still in its early stages, DECT utilization in pulmonary and cardiovascular pathologies is emerging. It includes applications such as pulmonary embolism, pulmonary hypertension, myocardial perfusion, and coronary artery assessment. This article discusses DECT principles and their current and emerging applications in thoracic imaging.

Giant Right Coronary Ostial Aneurysm in a Patient With Marfan Syndrome.

Aortic root dilation and aortic insufficiency are prominent causes of morbidity in Marfan syndrome. These pathologies necessitate surgical repair, including aortic root and aortic valve replacement procedures, to improve prognosis. Coronary artery aneurysms, particularly giant coronary ostial aneurysms, are rare complications of these surgeries in the Marfan population. Due to the significant life-threatening sequelae of coronary artery aneurysms, it is imperative to bring attention regarding this complication to the radiologist assessing thoracic imaging in this patient population.

Endobronchial Tuberculosis and Bronchostenosis: A Rare Case of Bronchial Occlusion in a Patient With History of Tuberculosis.

Pulmonary tuberculosis is common worldwide, and many of these patients develop endobronchial tuberculosis (EBTB). Bronchostenosis is a known complication of EBTB though most patients with endobronchial stenosis do not develop severe bronchostenosis or occlusion. We present a rare case of a patient with a right upper lobe bronchus occlusion and a history of tuberculosis.

Recurrent Metastatic Breast Cancer in Internal Mammary Lymph Nodes along the Translocated Left Internal Mammary Artery Bypass Graft.

Internal mammary lymph node (IMLN) is the second most common site for nodal metastases in breast cancer. The authors present a case of a 58-year-old woman with a history of coronary artery bypass graft surgery 1 year prior who presented with a neck mass. Imaging showed an enlarged IMLN along the course of the translocated left internal mammary artery (LIMA) bypass graft on the surface of the heart, and the patient was later proven to have recurrent breast cancer. To the authors' knowledge, this is the first case report in the literature of a breast cancer recurrence in an IMLN along the postoperative translocated LIMA bypass graft. Keywords: Adults, CT, PET/CT, Breast, Thorax, Lymphatic, Metastases © RSNA, 2021.

Complete clinical response after neoadjuvant chemoradiation therapy for distal rectal cancer: characterization of clinical and endoscopic findings for standardization.

BACKGROUND: Complete tumor regression may develop after neoadjuvant chemoradiation therapy for distal rectal cancer. Studies have suggested that selected patients with complete clinical response may avoid radical surgery and close surveillance may provide good outcomes with no oncologic compromise. However, definition of complete clinical response is often imprecise and may vary between different studies. The aim of this study is to provide a clear definition for a complete clinical response after neoadjuvant chemoradiation therapy in patients with distal rectal cancer in addition to actual endoscopic videos from patients managed nonoperatively. METHODS: Patients with nonmetastatic distal rectal cancer treated by neoadjuvant chemoradiation therapy, including 50.4 Gy and concomitant 5-fluorouracil and leucovorin, were assessed for tumor response at least 8 weeks after chemoradiation therapy completion. Complete and incomplete clinical responses were defined based on clinical and endoscopic findings. Patients with complete clinical response were not immediately operated on and were closely followed. Early and late endoscopic findings were recorded. RESULTS: Definition of a complete clinical response should be based on very strict clinical and endoscopic criteria. The finding of any residual superficial ulceration, irregularity, or nodule should prompt surgical attention, including transanal full-thickness excision or even a radical resection with total mesorectal excision. Standard or incisional biopsies should be avoided in this setting. Complete clinical responders should harbor no more than whitening of the mucosa, teleangiectasia with mucosal integrity to be considered for a nonoperative approach. In the presence of these findings, regularly scheduled reassessments may provide a safe alternative to these patients with early detection of recurrent disease. CONCLUSION: Strict definition of the clinical and endoscopic findings of patients experiencing complete clinical response after neoadjuvant chemoradiation therapy may provide a useful tool for the understanding of outcomes of patients managed with no immediate surgery allowing standardization of classifications and comparison between the experiences of different institutions.

Complicated Complication: How Interventional Radiologists Should Manage Acute Iatrogenic Cardiac Tamponade.

Computed tomography guided biopsies are common interventional procedures that are necessary for confirmation of imaging findings. Additionally, percutaneous biopsies are necessary for the elucidation of a patient's clinical findings with disease pathology. Though interventionists perform these procedures regularly without consequence, various complications may arise depending on the tissues biopsied. Examples of such complications may include hemorrhage, hematoma formation, or perforation of surrounding vessels. In the case of mediastinal biopsies, less common but higher-risk complications may include pneumothorax, perforation of arterial vessels, and damage to the cardiac tissues resulting in decompensation. Interventionists should understand the risks of performing these procedures and should be prepared to intervene if life-threatening complications arise. As interventional cardiologists are often prepared to manage decompensating cardiac complications, interventional radiologists must likewise anticipate the same to occur when conducting procedures that may affect cardiac tissues. The following case demonstrates a technique for correcting a complicated complication arising from a mediastinal biopsy, which resulted in a pericardial effusion and patient decompensation.

Incidental diagnosis of appendiceal mucocele with vaginal ultrasonography and computed tomography.

BACKGROUND: Appendiceal mucocele is an uncommon entity that may be encountered at the time of abdominal surgery performed for an unrelated indication. The diagnosis may be suggested by imaging with ultrasonography or computed tomography of the abdomen and pelvis. Whereas early resection is curative, failure to recognize the disorder may lead to rupture and the devastating consequences of pseudomyxoma peritonei. CASE: Following an annual gynecologic checkup in a healthy 63-year-old woman, vaginal ultrasonography along with a subsequent computed tomographic study raised the possibility that an incidental appendiceal mucocele was present. At laparoscopy, this diagnosis was confirmed and the lesion was resected using minimally invasive techniques. CONCLUSION: Early diagnosis and treatment of appendiceal mucocele facilitates the successful management of this rare disorder.

Adenosine 5'-triphosphate and its relationship with other mediators that activate pelvic nerve afferent neurons in the rat colorectum.

Evidence of a role for purinergic signalling in visceral afferents involving P2X(2), P2X(3) and P2Y(1) receptors exists, which appears to be important during inflammation. This study aimed to evaluate the degree of interaction between adenosine 5'-triphosphate (ATP) and other mediators that activate sensory nerves in the colorectum. Recordings from pelvic nerve afferents were made during application of agents to the in-vitro colorectal preparation. Analysis allowed calculation of single unit activity. When applied individually, bradykinin (78%) and 5-hydoxytryptamine (77%) activated the greatest number of neurons, followed by substance P, protons, ATP and capsaicin. Prostaglandin E(2) stimulated the least number (54%) and had a longer latency. Seventy-seven percent of all units studied either responded to both ATP and capsaicin or to neither, giving the greatest degree of activity correlation. Five percent of units were activated by all seven agents and no units were activated by a single agent alone. 5-hydroxytryptamine, capsaicin and protons, when co-applied with ATP, increased pelvic nerve activity to a greater degree than the sum of the individual responses. It is concluded that ATP activates pelvic nerve afferents and acts synergistically with protons, capsaicin and 5-hydroxytryptamine. The pattern of neuronal activation suggests that visceral afferents are polymodal but the receptor expression on their terminals is variable.

Increased 5-HT(3)-mediated signalling in pelvic afferent neurons from mice deficient in P2X(2) and/or P2X (3) receptor subunits.

Extracellular ATP and 5-hydroxytryptamine (5-HT) are both involved in visceral sensory pathways by interacting with P2X and 5-HT(3) receptors, respectively. We have investigated the changes in P2X and 5-HT(3)-mediated signalling in pelvic afferent neurons in mice deficient in P2X(2) and/or P2X(3) subunits by whole-cell recording of L(6)-S(2) dorsal root ganglion (DRG) neurons and by multi-unit recording of pelvic afferents of the colorectum. In wildtype DRG neurons, ATP evoked transient, sustained or mixed (biphasic) inward currents. Transient currents were absent in P2X(3) (-/-) neurons, whereas sustained currents were absent in P2X(2) (-/-) DRG neurons. Neither transient nor sustained currents were observed following application of ATP or alpha,beta-methylene ATP (alpha,beta-meATP) in P2X(2)/P2X(3) (Dbl-/-) DRG neurons. 5-HT was found to induce a fast inward current in 63% of DRG neurons from wildtype mice, which was blocked by tropisetron, a 5-HT(3) receptor antagonist. The percentage of DRG neurons responding to 5-HT was significantly increased in P2X (2) (-/-), P2X(3) (-/-) and P2X(2)/P2X(3) (Dbl-/-) mice, and the amplitude of 5-HT response was significantly increased in P2X(2)/P2X(3) (Dbl-/-) mice. The pelvic afferent response to colorectal distension was attenuated in P2X(2)/P2X(3) (Dbl-/-) mice, but the response to serosal application of 5-HT was enhanced. Furthermore, tropisetron resulted in a greater reduction in pelvic afferent responses to colorectal distension in the P2X(2)/P2X(3) (Dbl-/-) preparations. These data suggest that P2X receptors containing the P2X(2) and/or P2X(3) subunits mediate purinergic activation of colorectal afferents and that 5-HT signalling in pelvic afferent neurons is up-regulated in mice lacking P2X(2) or P2X(3) receptor genes. This effect is more pronounced when both subunits are absent.

Purinergic mechanisms contribute to mechanosensory transduction in the rat colorectum.

BACKGROUND & AIMS: Adenosine 5'-triphosphate plays a role in peripheral sensory mechanisms and, in particular, mechanosensory transduction in the urinary system. P2X(3) receptors are selectively expressed on small-diameter sensory neurons in the dorsal root ganglia; sensory neurons from dorsal root ganglia L1 and S1 supply the colorectum. This study investigated whether purinergic signaling contributes to mechanosensory transduction in the rat colorectum. METHODS: A novel in vitro rat colorectal preparation was used to elucidate whether adenosine 5'-triphosphate is released from the mucosa in response to distention and to evaluate whether it contributes to sensory nerve discharge during distention. RESULTS: P2X(3) receptor immunostaining was present on subpopulations of neurons in L1 and S1 dorsal root ganglia, which supply the rat colorectum. Distention of the colorectum led to pressure-dependent increases in adenosine 5'-triphosphate release from colorectal epithelial cells and also evoked pelvic nerve excitation, which was mimicked by application of adenosine 5'-triphosphate and alpha,beta-methylene adenosine 5'-triphosphate. The sensory nerve discharges evoked by distention were potentiated by alpha,beta-methylene adenosine 5'-triphosphate and ARL-67156, an adenosine triphosphatase inhibitor, and were attenuated by the selective P2X(1), P2X(3), and P2X(2/3) antagonist 2',3'-O-trinitrophenyl-adenosine 5'-triphosphate and by the nonselective P2 antagonists pyridoxyl 5-phosphate 6-azophenyl-2',4'-disulfonic acid and suramin. Adenosine, after ectoenzymatic breakdown of adenosine 5'-triphosphate, seems to be involved in the longer-lasting distention-evoked sensory discharge. Single-fiber analysis showed that high-threshold fibers were particularly affected by alpha,beta-methylene adenosine 5'-triphosphate, suggesting a correlation between purinergic activation and nociceptive stimuli. CONCLUSIONS: Adenosine 5'-triphosphate contributes to mechanosensory transduction in the rat colorectum, and this is probably associated with pain.

Purinergic component of mechanosensory transduction is increased in a rat model of colitis.

ATP contributes to mechanosensory transduction in the rat colorectum. P2X3 receptors are present on dorsal root ganglia (DRG) neurons that supply this area of the gut. Previous studies have shown an increased role for ATP in inflamed tissues. We aimed to investigate whether an increased purinergic component exists during mechanosensory transduction in a rat model of colitis. An in vitro rat colorectal preparation was used to investigate whether distension increased ATP release and to evaluate the role of purinergic antagonists in distension-evoked sensory discharges in the pelvic nerve in normal and colitis preparations. DRG neuron purinoceptors were also studied. Distension-evoked responses in the colitis model were attenuated to a significantly greater extent by 2',3'-O-trinitrophenyl-ATP and pyridoxyl 5-phosphate 6-azophenyl-2',4'-disulfonic acid. Inflammation caused augmented distension-evoked sensory nerve excitation after application of ATP and alpha,beta-methylene ATP. Single-fiber analysis confirmed that mean firing per unit was increased. Distension-evoked increases in ATP release from epithelial cells were substantially higher. The number of DRG neurons responding to ATP and the number of those staining for the P2X3 receptor, particularly those containing calcitonin gene-related peptide, were increased. Adenosine, after ectoenzymatic breakdown of ATP, is involved to a lesser degree in the longer-lasting distension-evoked sensory discharge, suggesting reduced ATPase activity. It was therefore concluded that ATP has an enhanced role in mechanosensory transduction in the inflamed rat colorectum. The underlying mechanisms appear to involve increased distension-evoked release of ATP as well as an increase in the number of DRG neurons supplying the colorectum expressing P2X3 receptors, especially those containing calcitonin gene-related peptide.