Contribution of diffusion-weighted imaging to conventional MRI for detection of haemorrhagic infarction in ovary torsion

Clinical Utility of Diffusion-Weighted Imaging in Gynecological Imaging: Revisited

ABSTRACT

Diffusion-weighted imaging (DWI) is an increasingly valuable sequence in daily clinical practice, providing both functional and morphological information. The use of DWI can help quantify diffusion using the apparent diffusion coefficient, which reflects the physiological features of the tissue and tumor microcirculation. This knowledge is crucial for understanding and interpreting gynecological imaging. This article reviews the clinical utility of DWI for gynecological imaging, highlighting its ability to aid in the detection of endometrial and cervical cancers, as well as tumor extension and metastasis. In addition, DWI can easily detect the solid components of ovarian cancer (including dissemination), assist in the diagnosis of adnexal torsion, and potentially show bone marrow status. Apparent diffusion coefficient measurement is useful for differentiating between endometrial lesions, uterine leiomyomas, and sarcomas, and may provide important information for predicting the prognosis of gynecological cancers.

The Society for Pediatric Radiology Magnetic Resonance Imaging and Emergency and Trauma Imaging Committees' consensus protocol recommendation for rapid MRI for evaluating suspected appendicitis in children

The imaging evaluation of acute abdominal pain in children with suspected appendicitis has evolved to include rapid abdominopelvic MRI (rMRI) over recent years. Through a collaborative effort between the Magnetic Resonance Imaging (MRI) and Emergency and Trauma Imaging Committees of the Society for Pediatric Radiology (SPR), we conducted a survey on the utilization of rMRI to assess practice specifics and protocols. Subsequently, we present a proposed consensus rMRI protocol derived from the survey results, literature review, and discussion and consensus between committee members.

All that glitters are not gold: holds true in female adnexal lesions

Background

Adnexal mass lesions are commonly encountered pathologies that creates diagnostic challenges for radiologist. Diffusion weighted imaging is a vital tool in the radiologist armamentarium for improving the diagnostic accuracy of adnexal lesions other than routine spine echo sequences.

Main body

Functional information about the lesion regarding the mobility of the water molecules in its tissue is assessed by diffusion weighted imaging. In addition to the solid malignant neoplasm, normal blood, fat, necrosis and pus also shows restricted diffusion.

Conclusion

All the lesion that shows restriction in the DWI are not malignant, but converse is mostly true. Knowledge regarding the non-malignant lesion in the ovary that shows restricted diffusion will give a clue in diagnosis, management and treatment of the adnexal lesions.

Multimodality imaging review for suspected ovarian torsion cases in children

OBJECTIVES

Ovarian torsion (OT), although rare, can be described as a complete or partial twist of the ovary with impairment of blood flow. Although occurring at any age, it is more common in children and during pregnancy. Presenting symptoms are non-specific but include either persistent or intermittent acute abdominal pain, making early diagnosis difficult. Delayed diagnosis is associated with an increased need for oophorectomy. The aim of this literature review is to establish the safest and most efficacious imaging strategy for OT by comparing and contrasting evidence for current imaging modalities found in the literature.

KEY FINDINGS

Characteristically, OT can be identified through a combination of findings some of which includes an enlarged ovary, multiple follicles at the periphery and a "whirlpool" sign. Currently, ultrasound is the preferred primary imaging modality; although computed tomography (CT) and magnetic resonance imaging (MRI) may also be used when findings are equivocal; with MRI being the safer option.

CONCLUSION

Ultimately, while it is true that ovarian torsion is not a common cause of acute abdominal pain in children, it should always be considered in the differential diagnosis. Prior to selecting an imaging modality; the clinical presentation, age group, possible radiation dose and availability of the modality needs to be considered to ensure the appropriate imaging strategy.

IMPLICATIONS FOR PRACTICE

With new tools such as scoring systems, B-flow imaging (BFI), diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) currently being explored for possible use in the future, early diagnosis of OT may be attainable. Thus, reducing the likelihood of adverse complications and consequently the need for oophorectomy.

Added value of MRI for the diagnosis of adnexal torsion in children and adolescents after inconclusive ultrasound examination

PURPOSE

The purpose of this study was to assess the performance of magnetic resonance imaging (MRI) in children and adolescents with suspected adnexal torsion (AT) after inconclusive initial ultrasound examination.

MATERIALS AND METHODS

Twenty-eight girls with a mean age of 12±4 (SD) years (range: 1 month to 18years) were included. All had clinically suspected AT and inconclusive initial ultrasound findings followed by pelvic MRI as a second-line imaging modality. The final diagnosis was obtained by surgery or follow-up. Two radiologists blinded to the clinical, ultrasound and surgical data, retrospectively and independently reviewed MRI examinations. Clinical and MRI features associated with AT were searched for using univariate analyses.

RESULT

Among the 28 patients, 10/28 patients (36%) had AT and 22/28 (79%) had an ovarian or tubal mass. AT was associated with an age<13years (OR: 10.7; 95% CI: 1.3-148.2) (P=0.022) and a whirlpool sign at MRI (OR: 61.0; median unbiased estimate, 7.2) (P<0.0001). When a mass was present, the best quantitative MRI criteria for AT were mass volume and ovary-corrected volume≥30cm³ (κ=0.72 and 0.61, respectively), mass axis length≥5cm (κ=0.90), and mass surface area≥14 cm² (κ=0.58), with moderate to almost perfect interobserver agreement. The overall sensitivity, specificity and accuracy of MRI for the diagnosis of AT were 100% (10/10; 95% CI: 69-100), 94% (17/18; 95% CI: 73-100) and 96% (27/28; 95% CI: 82-100) respectively, with perfect interobserver agreement (κ=1).

CONCLUSION

In pediatric patients with suspected AT and inconclusive initial ultrasound examination, a strategy including MRI as a second-line imaging modality should be considered if MRI does not delay a potential surgery.

Susceptibility-weighted MR sequence for the evaluation of ovarian masses with torsion

OBJECTIVE

Adnexal torsion is a rare gynecologic emergency caused by twisting of an adnexal mass. Twisted vascular pedicle is the most specific imaging finding for adnexal torsion, however, identification of twisted vascular pedicle can be challenging. The purpose of this study is to evaluate the feasibility of susceptibility-weighted MR sequence (SWS) for the diagnosis of adnexal torsion.

METHODS

MR imaging including SWS (SWAN: susceptibility-weighted angiography) of surgically proven four benign ovarian masses with torsion (one acute and three subacute to chronic torsions) were retrospectively evaluated. Three cystic masses and one solid mass were included in this study.

RESULTS

High signal intensity venous thrombus within the twisted vascular pedicle on T₁-weighted imaging (T₁WI) was detected in three lesions with subacute to chronic torsion (75%) but not in one lesion with acute torsion, whereas susceptibility-induced signal voids within the twisted vascular pedicle on SWAN were detected in all four lesions (100%).

CONCLUSION

The demonstration of venous thrombus in the twisted vascular pedicle by SWS may be diagnostic for adnexal torsion.

ADVANCES IN KNOWLEDGE

SWS can detect blood products sensitively and can reveal venous thrombus in the twisted vascular pedicle, which may be helpful for the diagnosis of adnexal torsion.

MRI of Acute Gynecologic Conditions

Although usually not a first-line imaging modality in the setting of acute pelvic pain, magnetic resonance imaging (MRI) is able to depict and characterize a wide range gynecologic diagnoses with high accuracy. Lack of ionizing radiation renders MRI particularly useful for assessment of pregnant women and children. Furthermore, inherent high soft-tissue resolution of MRI allows accurate diagnosis without intravenous contrast use, which is advantageous for patients with renal insufficiency and pregnant patients. Familiarity with the typical MRI appearance of various acute gynecologic conditions helps establish the correct diagnosis. This article reviews the common MRI findings of acute gynecologic processes, in both pregnant and nonpregnant patients. Level of Evidence: 3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1291-1309.