iRadiology最新文献

Targeted alpha (α) therapy (TAT) is an emerging therapeutic strategy for cancer treatment. To evaluate the safety and efficacy of targeted α-therapy, the biodistribution and internal radiation dose of α-emitting radionuclides should be determined. In vivo imaging of these radionuclides often involves the detection of gamma rays, X-rays, and positrons generated during their complex decay processes. This review aims to classify the α-emitting radionuclides (astatine-211, actinium-225, radium-223, bismuth-212, bismuth-213, thorium-227, and terbium-149) according to their imageable signals. Additionally, this study summarizes various imaging modalities, including gamma camera imaging, single-photon emission computed tomography, positron emission tomography, Compton imaging, bremsstrahlung imaging, and Cerenkov luminescence imaging, which hold potential for imaging α-emitting radionuclides, to explore their biomedical applications in qualitative nuclide tracing and diagnosis, quantifying pharmacokinetics, and assessing prognosis and response to therapy.

Cardiac-cerebral vascular diseases (CCVDs) are acknowledged as a major threat to public health, leading to more than one-third of all deaths worldwide. The complex anatomical structure and immune features of blood vessels significantly affect the development of CCVDs, and magnetic resonance angiography (MRA) is one of the main diagnostic approaches for the accurate diagnosis and prognosis of CCVDs. However, MRA suffers from intrinsic problems derived from its blood flow-dependency, and the clinical Gd-chelating contrast agents are limited by their rapid vascular extravasation. Over the past decade, spurred on by nanoscience and nanotechnology, numerous contrast agents based on magnetic nanomaterials have been developed to enhance the contrast of MRA, with these including iron oxide nanoparticles, rare earth-doped nanoparticles, and metal-organic coordination polymers. The molecular MR imaging of vasculopathy using specific nanoprobes has been explored to obtain a better understanding of the molecular aspects of CCVDs. In this review, the state of the art in MRA nanoprobes is introduced, and recent achievements in the diagnosis of CCVDs using MR imaging are summarized. Additionally, the future prospects and limitations of MRA based on nanoprobes are discussed. The current review provides methodological designs and ideas for subsequent MRA nanoprobes.

Quantitative susceptibility mapping (QSM) is an advanced post-processing technique in magnetic resonance imaging that offers precise measurements of tissue magnetic susceptibility with impressive spatial resolution and sensitivity. This review examines the potential of QSM as a biomarker for early detection and monitoring of amyotrophic lateral sclerosis (ALS). Since 2015, studies have consistently reported increased QSM values in the motor regions of individuals with ALS, indicating significant iron deposition. Iron accumulation is associated with dysfunction of the upper motor neurons and faster disease progression. Notably, increased QSM values were also observed in the critical subcortical areas responsible for motor function and cognitive control. However, standardizing optimized protocols, including background field removal algorithms, phase unwrapping approaches, and methods for final susceptibility map reconstruction, has the potential to enhance the consistency and reliability of QSM as an ALS biomarker. Overall, the current body of evidence strongly supports QSM in detecting iron dysregulation associated with neurodegeneration in both motor and extra-motor regions in ALS. Furthermore, QSM's remarkable sensitivity to early pathological iron changes and its high specificity in distinguishing ALS positions make it a promising diagnostic and progression-tracking biomarker.

Extracellular vesicles (EVs) are tiny vesicles released by various cells that contain a variety of proteins, lipids, and nucleic acids, which can have a wide range of effects on other cells. The dynamic composition and contents of EVs can serve as sensitive biomarkers for diagnosing and monitoring various cardiovascular diseases (CVDs). In addition to their diagnostic potential, EVs are therapeutic agents capable of precise modulation and amelioration of CVDs, because of their innate ability to encapsulate and deliver bioactive molecules. This growing field reveals the intricate interplay between EVs and cardiovascular pathophysiology, showing that EVs can act as messengers of intercellular communication for CVD regenerative therapy. Extracellular vesicles serve as dual agents in the field of theranostics, both as diagnostic biomarkers able to decode nuanced molecular signatures of CVDs and as potent vehicles for targeted therapeutic interventions. This review delves into the evolving landscape of EVs, uncovering their diagnostic and therapeutic prospects and emphasizing their growing importance in shaping the future of cardiovascular theranostics.

A 69-year-old male with a known history (Hx) of chronic kidney disease (CKD) was presented with a 2-day Hx of inability to flex the proximal and distal interphalangeal (DIP) joints of the first, second, and third digits of his left hand. Notably, he retained the ability to flex the proximal and DIP joints of the fourth and fifth fingers. This presentation followed balloon fistuloplasty (BF) performed to address stenosis of an arteriovenous fistula between the radial artery and cephalic vein.

Physical examination revealed swelling and erythema on the ventral aspect of left upper arm. He was referred for ultrasonography (USG) for the same.

Ultrasound imaging of the left upper arm was conducted. The examination revealed a well-defined cystic lesion measuring 27 × 7 × 10 mm, originating from the wall of the brachial artery. Doppler study demonstrated a “ying yang” sign on color Doppler, indicative of a pseudoaneurysm (PNA). Notably, the PNA was observed to pulsate against the median nerve (MN), leading to neuropraxia (Figure 1).

Under ultrasound guidance, compression therapy for 15 min was performed and complete obliteration of lumen was achieved and was confirmed on Doppler study showing no flow in the lumen of PNA (Figure 2).

The MN descends down the arm, initially lateral to the brachial artery. Halfway down the arm, the nerve crosses over the brachial artery and becomes situated medially [1]. The MN is formed from all anterior rami of C5-T1 [2]. It predominantly provides motor innervation to the flexor muscles of the forearm and hand and also provides sensory innervation to the dorsal aspect (nail bed) of the distal first two digits of the hand, the palmar aspect of the thumb, index, middle, and half of the ring finger, the palm, as well as the medial aspect of the forearm [3].

MN neuropraxia associated with post iatrogenic vascular injury to the brachial artery is very low and is a degraded complication. Brachial PNA could result in compression of the MN in the arm leading to an ischemic injury [4]. In this case, the patient was presented with pain and erythema of the left upper arm. From the given Hx, the patient was a known case of CKD and was undergoing hemodialysis for the same. A fistula between the radial artery and cephalic vein was created. Later, after 5 months of arterio-venous fistula, he developed features of arterio-venous fistula stenosis, and BF was advised for the same.

In this patient, a complication of arterio-venous stenosis was diagnosed. USG and color Doppler of the upper arm at the incision site showed a PNA, which was seen pulsating and compressing the MN. Thus, a diagnosis of neuropraxia was made. Compression therapy for 15 min was performed, and complete occlusion of the PNA was obtained.

Our case underscores the significance of prompt recognition and management of PNAs following vascular interventions. Utilization of high-re

Positron emission tomography (PET) is a noninvasive molecular imaging technique that utilizes biologically active radiolabeled compounds to image biochemical processes. As such, PET can provide important pathophysiological information associated with pain of different etiologies. Consequently, the information obtained using PET often combined with magnetic resonance imaging or computed tomography can provide useful information for diagnosing and monitoring changes associated with pain. This review covers the most important PET tracers that have been used to image pain including tracers for fundamental biological processes such as glucose metabolism and cerebral blood flow, to receptor-specific tracers such as ion channels and neurotransmitters. For each tracer, we describe the structure and radiochemical synthesis of the tracer followed by a brief summary of the available preclinical and clinical studies. By providing a summary of the PET tracers that have been employed for PET imaging of pain, this review aims to serve as a reference for preclinical, translational, and clinical investigators interested in molecular imaging of pain. Finally, the review ends with an outlook of the needs and opportunities in this area.