Clinical Value and Operational Risks of MRI in ICU patients - A Retrospective Analysis Performed at a University Medical Center

PURPOSE

 Intensive care unit (ICU) patients have a high risk of developing complications when leaving the ICU for diagnostic procedures or therapeutic interventions. Our study examined the frequency of adverse events associated with magnetic resonance imaging (MRI) of intensive care patients and the extent of changes in therapy due to the MRI scan to weigh the risks associated with the scan against the potential benefits of an MR scan, using a change in therapy as an indicator of benefit.

MATERIALS AND METHODS

 4434 ICU patients (January to December 2015) were identified by Hospital Information System (SAP-R/3 IS-H, Walldorf, Germany), ICU patient data management system Metavision (iMDsoft, Israel), and Radiology Information System (Nexus.medRIS, Version 8.42, Nexus, Germany). All intensive care and medical records (HIS) and MRI reports (RIS) were matched and further evaluated in a retrospective case-to-case analysis for biometric data, mechanical ventilation, ICU requirements, planned postoperative vs. emergency diagnostic requirements, complications and impact on further diagnosis or therapy.

RESULTS

 Out of 4434 ICU patients, 322 ICU patients (7.3 %) underwent a total of 385 MRI examinations. 167 patients needed a total of 215 emergency scans, while 155 patients underwent 170 planned postoperative MRI exams. 158 (94.6 %) out of 167 emergency scan patients were ventilated under continuous intravenous medication and monitoring. In the planned postoperative group, only 6 (3.9 %) out of 155 were ventilated, but a total of 38 (24.5 %) were under continuous medication. 111 patients were accompanied by nurses only during MRI. Only one severe adverse event (0.3 %) was noted and was attributed to study preparation (n = 385). In 8 MRI examinations (2.1 %), the examination was interrupted or cancelled due to the patients' condition. While all MRI examinations in the planned group were completed (n = 170, 100 %) (e. g., postoperative controls), only 207 out of 215 (96.3 %) could be performed for emergency diagnostic reasons. MRI influenced the clinical course with a change in diagnosis or therapy in 74 (19.2 %) of all 385 MRI examinations performed, and in the emergency diagnostic group it was 31.2 % (n = 67/215).

CONCLUSION

 Nearly 20 % of MRI examinations of ICU patients resulted in a change of therapy. With only one potentially life-threatening adverse event (0.3 %) during transport and the MRI examination, the risk seems to be outweighed by the diagnostic benefit.

KEY POINTS

· The risk of adverse events associated with MRI scans in ICU patients is low.. · The rate of premature termination of ICU patients' MRI scans is low.. · Almost 20 % of ICU patients' MRI scans lead to a change of therapy..

[Incidental and "leave me alone" findings of abdominal organs-part 1 : Liver, gall ducts and pancreas]

Incidentalomas of the parenchymal organs of the abdomen, i.e. radiological findings in these organs that are not the primary focus of the clinical question, are frequent in this region of the body. In particular, findings presumed to be unimportant, such as cystic masses in the liver, the bile duct system or the pancreas, initially appear to be irrelevant in the diagnosis. For the liver we define the mostly clearly diagnosable simple cysts and hemangiomas as leave me alone lesions. Otherwise, we recommend a classification of incidentalomas into the three major categories (<0.5 cm, 0.5-1.5 cm and >1.5 cm) as well as an assessment with respect to clearly benign and suspect imaging characteristics in the context of a classification of patients into three different risk groups.

[Assessment of teleradiology patients in a major regional hospital]

PURPOSE

To evaluate teleradiology examinations regarding the most frequently requested exams and examined body regions. Additionally, the frequency of pathological changes depending on the examined region and clinical situation as well as the time profile for requesting teleradiology (daytime, day of the week) were analyzed.

MATERIALS AND METHODS

A retrospective analysis of all consecutive teleradiology exams in 2018 that were reported in the radiology department of a major regional hospital and scanned in three referring primary health care institutions regarding clinical history, working diagnosis and requested body region was performed. Additionally, the date and time of the examination were analyzed.

RESULTS

A total of 1207 CT (computer tomography) scans that were reported as part of the teleradiology agreement were included. The most frequently requested examination was a cranial CT (77.9%) with 14.6% pathological findings, followed by abdominal CT (14%) with 63.9% pathological changes, spine/extremities (8.8%) with 50% pathological changes and CT of the chest (7.9%) with 53.7% abnormal scans. Most teleradiology requests were referred on weekends between 8 am and 4 pm, followed by 4 pm to 6 pm on weekdays. The smallest number of scans was requested between 2 am and 4 am.

CONCLUSION

Most teleradiology CT requests focus on brain examinations, followed by abdominal CT, CT of the spine and extremities and CT chest. Most cranial CTs do not show an acute pathology, while abdominal CTs had the highest rate of pathological findings.

[Acceptance of medical apps and e‑books among German radiologists]

PURPOSE

Smartphones, tablet PCs, mobile applications (apps) and electronic book files (e-books) affect our lives in private and job-related settings. The aim of this study was to analyze the behavior of radiologists on smartphones, tablet PCs and e‑books and to investigate its effect on their daily work.

MATERIALS AND METHODS

An online survey containing of 23 questions was conducted using Survey Monkey© ( www.surveymonkey.com ). The invitation to the survey was done using the newsletter of the German Radiological Society (DRG). The acquired data was automatically stored by the software and then analyzed using descriptive statistics.

RESULTS

In total, 104 radiologists (29% female) participated in the online survey. Of these, 93% and 96.5% owned a smartphone or a tablet PC, respectively, and 72% and 67% used medical apps and e‑books, respectively. Through their use, 31% found moderate and 41% found enormous improvement in their daily work. A majority of participating radiologists would be willing to pay an increased user fee for optimized apps or e‑books.

CONCLUSION

With currently only moderate individual benefit of mobile medical apps and e‑books, there is a widespread need for optimally configured apps and e‑books with a correspondingly high market potential.

KEY POINTS

(1) Radiologists use smartphones (93%) or tablet PCs (96.5%); (2) 72% of radiologists use a smartphone or tablet PC for medical material; (3) 53% of radiologists report significant assistance from or a high value of the mobile medical applications used; (4) There is a willingness to pay a license fee for optimized mobile applications or e‑books.

Informed Consent in Contrast-Enhanced CT: Understanding of Risks and Identification of Possible Prognostic Factors

PURPOSE

Aim of our study was to assess understanding of risks associated with intravascular application of contrast media in patients undergoing CT examination. We wanted to evaluate epidemiologic and socio-economic prognostic factors for a higher understanding of risks. Additionally, we evaluated a possible correlation between an extensive, outcome-oriented oral informed consent and better understanding of risks.

MATERIALS AND METHODS

120 patients distributed in 2 study arms participated in this prospective study. In study arm I, the treating physician was not informed that his patients participated in a study whereas the physician in study arm II knew about the survey. After the informed consent we performed a standardized, semi-structured interview to enquire the 3 most frequent risks of intravascular application of contrast agents (anaphylactoid reactions, nephropathy and thyrotoxic crisis) and epidemiologic data. The understanding of the risks was evaluated using a 6 point scale.

RESULTS

Patients scored 3.73 points in study arm I and 4.93 points in arm II on average. The statistical difference between both study arms was highly significant (p <0.001). In a combined logistic regression analysis, only "higher education" (p = 0.001) and participation in study arm II (p =0 .001) showed a significant connection to a better understanding of risks.

CONCLUSION

Patients profit from an outcome-oriented and individualized informed consent. Due to the significant correlation between educational level and understanding of risks, informed consent should be adjusted to the educational status of the individual patient, e. g. by using didactic aids or individualized information sheets.

Evaluation of the contribution of radiological imaging to the final diagnosis in medical case reports

PURPOSE

To evaluate the clinical value and impact of radiological imaging in published medial case reports.

METHODS

We analysed 671 consecutively published case reports of a peer-reviewed medical journal for case reports. The general use of radiological imaging as well as the specific imaging modality used in each case (ultrasound, x-ray, fluoroscopy, CT, MRI) was documented, and most importantly the 'final problem solver', i.e. the diagnostic modality giving the final clue to the patient's diagnosis, was identified.

RESULTS

In 511 of 671 (76.1 %) analysed case reports at least one radiological modality was used in the diagnostic cascade. In 28.6% of all cases the final diagnosis was achieved by radiological imaging. All other cases were solved by the patient's history and physical examination (15.2%), histology (12.4%), and blood analysis (9.6%). When radiology was the 'final problem solver', it was mainly CT (51.6%) and MRI (30.6%). In 52.2% of the case reports the radiological image was included in the article.

CONCLUSION

In case reports published in a prominent general medical journal radiological imaging is an important key player in the diagnostic process. In many cases, it is also the diagnostic tool which ultimately leads to determining the final diagnosis.

KEY POINTS

• Radiology was the most important specialty for finding the final diagnosis. • CT was the most successful problem-solving imaging modality followed by MRI. • MRI and CT had the best solution rates of more than 30%.

Diagnostic significance of rib series in minor thorax trauma compared to plain chest film and computed tomography

Background

Rib series (RS) are a special radiological technique to improve the visualization of the bony parts of the chest.

Objectives

The aim of this study was to evaluate the diagnostic accuracy of rib series in minor thorax trauma.

Methods

Retrospective study of 56 patients who received RS, 39 patients where additionally evaluated by plain chest film (PCF). All patients underwent a computed tomography (CT) of the chest. RS and PCF were re-read independently by three radiologists, the results were compared with the CT as goldstandard. Sensitivity, specificity, negative and positive predictive value were calculated. Significance in the differences of findings was determined by McNemar test, interobserver variability by Cohens kappa test.

Results

56 patients were evaluated (34 men, 22 women, mean age =61 y.). In 22 patients one or more rib fracture could be identified by CT. In 18 of these cases (82%) the correct diagnosis was made by RS, in 16 cases (73%) the correct number of involved ribs was detected. These differences were significant (p = 0.03). Specificity was 100%, negative and positive predictive value were 85% and 100%. Kappa values for the interobserver agreement was 0.92-0.96. Sensitivity of PCF was 46% and was significantly lower (p = 0.008) compared to CT.

Conclusions

Rib series does not seem to be an useful examination in evaluating minor thorax trauma. CT seems to be the method of choice to detect rib fractures, but the clinical value of the radiological proof has to be discussed and investigated in larger follow up studies.

Dynamic magnetic resonance defecography in 10 asymptomatic volunteers

AIM: Evaluation of the wide range of normal findings in asymptomatic women undergoing dynamic magnetic resonance (MR) defecography.

METHODS: MR defecography of 10 healthy female volunteers (median age: 31 years) without previous pregnancies or history of surgery were evaluated. The rectum was filled with 180 mL gadolinium ultrasound gel mixture. MR defecography was performed in the supine position. The pelvic floor was visualized with a dynamic T2-weighted sagittal plane where all relevant pelvic floor organs were acquired during defecation. The volunteers were instructed to relax and then to perform straining maneuvers to empty the rectum. The pubococcygeal line (PCGL) was used as the line of reference. The movement of pelvic floor organs was measured as the vertical distance to this reference line. Data were recorded in the resting position as well as during the defecation process with maximal straining. Examinations were performed and evaluated by two experienced abdominal radiologists without knowledge of patient history.

RESULTS: Average position of the anorectal junction was located at -5.3 mm at rest and -29.9 mm during straining. The anorectal angle widened significantly from 93° at rest to 109° during defecation. A rectocele was diagnosed in eight out of 10 volunteers showing an average diameter of 25.9 mm. The bladder base was located at a position of +23 mm at rest and descended to -8.1 mm during defecation in relation to the PCGL. The bladder base moved below the PCGL in six out of 10 volunteers, which was formally defined as a cystocele. The uterocervical junction was located at an average level of +43.1 mm at rest and at +7.9 mm during straining. The uterocervical junction of three volunteers fell below the PCGL; described formally as uterocervical prolapse.

CONCLUSION: Based on the range of standard values in asymptomatic volunteers, MR defecography values for pathological changes have to be re-evaluated.

Contrast-enhanced ultrasound for differential diagnosis of suspected GvHD in patients after allogeneic transplantation

GvHD is a serious complication in patients after allo-SCT, presenting with unspecific symptoms such as abdominal pain or cramps and diarrhea. Early diagnosis of GvHD, after differentiation from other causes leading to the same symptoms, such as viral or bacterial enteritis, is highly important because the time needed for diagnosing GvHD is directly correlated to a worsening of the outcome. We examined 23 patients presenting with the abdominal symptoms mentioned above, of whom 20 had received an allo-SCT in their history and were thus potential candidates for enteric GvHD. The other three patients were included because they also presented with abdominal symptoms similar to those of GvHD, which could be ruled out due to their history. We wanted to evaluate CEUS in these patients as an additional subgroup to gain more data on the value of CEUS in early detection of enteral GvHD and in the differentiation of GvHD against other causes of abdominal discomfort. All patients underwent CEUS with particular attention to penetration of the intravenously applied microbubbles in the bowel lumen. In the patients having allo-SCT in their history we strove to achieve histological confirmation of GvHD of the GI-tract. The resulting examinations were documented digitally. Out of 17 patients with confirmed GvHD of the GI tract, 14 showed penetration of the intravenously applied microbubbles into the bowel lumen, leading to a sensitivity and specificity of 82% and 100% for transmural bubble penetration for GvHD of the GI-Tract, since the patients without GvHD of the GI tract showed no transmural bubble penetration. In patients with viral or bacterial infections of the GI tract, no transmural penetration of the microbubbles into the bowel lumen was observed. For microbubble penetration as a criterion for GvHD of the GI-Tract, this leads to a negative predictive value (NPV) of 67%, and a positive predicative value (PPV) of 100%.

Comparison of high-resolution ultrasound and MR-enterography in patients with inflammatory bowel disease

AIM: To compare the results of high-resolution ultrasound (HR-US) and magnetic resonance enterography (MRE) examinations in patients with inflammatory bowel disease (IBD).

METHODS: The reports of 250 consecutive cases with known IBD, who had an MRE and HR-US examination, were retrospectively analyzed. Using a patient-based approach we evaluated morphological disease features such as affected bowel wall, stenosis, abscess and fistula. The comparison between the two modalities was based on the hypothesis, that any pathological change described in any imaging modality was a true finding, as no further standard of reference was available for complete assessment.

RESULTS: Two hundred and fifty examinations representing 207 different patients were evaluated. Both modalities assessed similar bowel wall changes in 65% of the examinations, with more US findings in 11% and more MRE findings in 15%. When the reports were analyzed with regard to “bowel wall inflammation”, US reported more findings in 2%, while MRE reported more findings in 53%. Stenoses were assessed to be identical in 8%, while US found more in 3% and MRE in 29% (P < 0.01). For abscess detection, US showed more findings in 2% (n = 4) while MRE detected more in 6% (n = 16). US detected more fistulas in 1% (n = 2), while MRE detected more in 13% (n = 32) (P < 0.001). The most common reason for no detected pathology by US was a difficult to assess anatomical region (lesser pelvis, n = 72).

CONCLUSION: US can miss clinically relevant pathological changes in patients with IBD mostly due to difficulty in assessing certain anatomical regions.