Israel Medical Association Journal

Background: Medical evaluation of a suspected meniscus injury begins with a history-taking and physical examination. Suspected meniscus injuries not responding to treatment are usually sent for imaging to confirm the diagnosis before arthroscopy. Tc-MDP bone single photon emission computed tomography (SPECT) scan has been suggested as an alternative to magnetic resonance imaging (MRI) in evaluating suspected knee meniscus tears.

Objectives: To examine the accuracy of knee SPECT as a tool to identify meniscus tears versus that of MRI as compared to the gold standard of arthroscopy.

Methods: The Israel Defense Forces database for 2005 through 2009 was searched according to the key words knee MRI, knee SPECT and knee arthroscopy. We identified 330 subjects who had undergone both a single knee SPECT and a single knee MRI prior to knee surgery. The medical files of 193 of the 330 subjects were randomly selected for review. A comparison was made between the preoperative SPECT and MRI studies and the arthroscopic finding. The sensitivity, specificity and accuracy were calculated.

Results: The subjects’ age was 21.3 ± 3.9. The agreement between SPECT and arthroscopy was 0.14 for the medial meniscus and 0.29 for the lateral meniscus. The agreement between MRI and arthroscopy was 0.59 for the medial meniscus and 0.69 for the lateral meniscus. SPECT scan was found to be 61% sensitive, 54% specific and 58% accurate in detecting common knee pathology, whereas MRI was found to be 95% sensitive, 67% specific and 85% accurate.

Conclusions: Knee SPECT has a lower sensitivity, specificity and accuracy than MRI in evaluating meniscal injuries and its use can result in increased unnecessary surgery.

Objectives: To evaluate the predictive value of V/Q scanning in patients with impaired renal function.

Methods: We assessed all patients with impaired renal function who underwent V/Q scanning. The patients studied included those who also had CTPA (group 1) and those who did not (group 2). We recorded the results of V/Q scanning, chest X-rays, CTPA, D-dimer levels, ultrasound of deep veins, and clinical probability for PE (Wells' score) in group 1. CTPA results were considered true results. Anticoagulant treatment was documented in all the patients.

Results: Of the 45 patients in group 1, 12 (22%) had positive CTPA for PE. The positive predictive value (PPV) for patients with high probability results on V/Q scanning for PE was 30%. Restricting results to D-dimer levels ≥ 1000 ng/ml added little to this value. Restricting results to Wells’ score ≥ 7 resulted in 72% PPV. The negative predictive values for low or moderate probability were ~79 % and ~67% respectively. Of the 95 patients in group 2, all those with high probability for PE were treated with anticoagulants.

Conclusions: Patients with impaired renal function and high probability for PE on V/Q scanning had very low PPV for PE. Due to the lack of CTPA studies, patients with high probability for PE on V/Q scanning were treated with anticoagulants.

Objectives: To assess the role of electrocardiography-gated CT-angiography (ECG-CTA) in the routine evaluation of CHD in neonates and infants particularly for the assessment of extracardiac findings.

Methods: The study cohort comprised 40 consecutive patients who underwent trans-thoracic echocardiography (TTE) and ECG-CTA. TTE and ECG-gated CTA findings regarding extracardiac vascular structures, coronary arteries and airways were compared with surgical or cardiac catheterization findings. Scans were evaluated for image quality using a subjective visual scale (from 1 to 4). Effective radiation dose was calculated for each scan.

Results: Median age was 28 ± 88 days and mean weight 3.7 ± 1.5 kg. Diagnostic quality was good or excellent (visual image score 3–4) in 39 of 40 scans (97.5%). ECG-CTA provided important additional information regarding extracardiac vascular structures and airway anatomy, complementing TTE in 75.6% of scans. Overall sensitivity of ECG-gated CTA for detecting extracardiac findings as compared with operative and cardiac catheterization findings was 97.6%. The calculated mean effective radiation dose was 1.4 ± 0.07 mSv (range 1.014–2.3 mSv).

Conclusions: ECG-CTA is an accurate modality for demonstrating extracardiac structures in complex CHD. It provides important complementary information to TTE regarding extracardiac vascular structures and coronary artery anatomy. This modality may obviate the need for invasive cardiac catheterization, thus exposing the patient to a much lower radiation dose. 

Objectives: To evaluate common misinterpretations of head CT scans by radiology residents in a level I trauma center ED.

Methods: We studied 960 head CT scans of patients admitted to our ED from January 2010 to May 2011. They were reviewed separately by two senior neuroradiologists and graded as being unimportant (score of 1), important but not requiring emergent treatment (score of 2), and important requiring urgent treatment (score of 3). We recorded the time of day the examination was performed, the year of residency, the site, subsite and side of the lesion, the pathology, the anatomical mistake, false-positive findings, and the attending neuroradiologists' score.

Results: A total of 955 examinations were interpreted of which 398 had misinterpreted findings that were entered into the database, with the possibility of multiple errors per examination. The overall misinterpretation rate was 41%. The most commonly missed pathologies were chronic infarcts, hypodense lesions, and mucosal thickening in the paranasal sinuses. The most common sites for misdiagnosis were brain lobes, sinuses and deep brain structures. The highest percentage of misinterpretation occurred between 14:30 and 20:00, and the lowest between 00:00 and 08:00 (P < 0.05). The overall percentage of errors involving pathologies with a score of 3 by at least one of the neuroradiologists was 4.7%. Third-year residents had an overall higher error rate and first-year residents had significantly more false-positive misinterpretations compared to the other residents.

Conclusions: The percentage of errors made by our residents in cases that required urgent treatment was comparable to the published data. We believe that the intense workload of radiology residents contributes to their misinterpretation of head CT findings.

Background: An outbreak of respiratory illness caused by a novel swine-origin influenza virus (influenza A/H1N1 2009) that began in Mexico was declared a global pandemic by the World Health Organization in June 2009. The pandemic affected many countries, including Israel.

Objectives: To compare the course of chest radiographic and computed tomography findings in patients who survived and those who died following admission to the intensive care unit (ICU) or intubation due to severe laboratory-confirmed swine-origin influenza A/H1N1 2009.

Methods: We retrospectively reviewed the patient records (267 radiographs, 8 CTs) of 22 patients (10 males, 12 females) aged 3.5–66 years (median 34) with confirmed influenza A/H1N1 2009, admitted to the ICU and/or intubated in five major Israeli medical centers during the period July–November 2009. We recorded demographic, clinical, and imaging findings –including pattern of opacification, extent, laterality, distribution, zone of findings, and presence/absence of nodular opacities– at initial radiography and during the course of disease, and compared the findings of survivors and non-survivors. Statistical significance was calculated using the Wilcoxon (continuous variables) and Fisher's exact tests (categorical variables).

Results: The most common findings on the initial chest radiography were airspace opacities, which were multifocal in 17patients (77%) and bilateral in 16 (73%), in the lower or lower and middle lung zones in 19 patients (86%). Large airspace nodules with indistinct margins were seen in 8 patients (36%). Twelve patients survived, 10 died. Patients who died had multiple background illnesses and were significantly older than survivors (P = 0.006). Radiologic findings for the two groups were not significantly different.

Conclusion: Airspace opacities, often with nodular appearance, were the most common findings among patients with severeinfluenza A/H1N1 2009. The course of radiologic findings was similar in patients with severe influenza A/H1N1 2009 whosurvived and those who died.