Israel Medical Association Journal

Background: Medical imaging and the resultant ionizing radiation exposure is a public concern due to the possible risk of cancer induction.

Objectives: To assess the accuracy of ultra-low-dose (ULD) chest computed tomography (CT) with denoising versus normal dose (ND) chest CT using the Lung CT Screening Reporting and Data System (Lung-RADS).

Methods: This prospective single-arm study comprised 52 patients who underwent both ND and ULD scans. Subsequently AI-based denoising methods were applied to produce a denoised ULD scan. Two chest radiologists independently and blindly assessed all scans. Each scan was assigned a Lung-RADS score and grouped as 1 + 2 and 3 + 4.

Results: The study included 30 men (58%) and 22 women (42%); mean age 69.9 ± 9 years (range 54–88). ULD scan radiation exposure was comparable on average to 3.6–4.8% of the radiation depending on patient BMI. Denoising increased signal-to-noise ratio by 27.7%. We found substantial inter-observer agreement in all scans for Lung-RADS grouping. Denoised scans performed better than ULD scans when negative likelihood ratio (LR-) was calculated (0.04–-0.08 vs. 0.08–0.12). Other than radiation changes, diameter measurement differences and part-solid nodules misclassification as a ground-glass nodule caused most Lung-RADS miscategorization.

Conclusions: When assessing asymptomatic patients for pulmonary nodules, finding a negative screen using ULD CT with denoising makes it highly unlikely for a patient to have a pulmonary nodule that requires aggressive investigation. Future studies of this technique should include larger cohorts and be considered for lung cancer screening as radiation exposure is radically reduced.

Objectives: To present a variety of radiologic findings on high resolution computerized tomography in eight sequential patients with COP[1], together with clinical and pathologic correlation.

Methods: Sequential HRCT[2] examinations of eight patients (four males) aged 53–80 years (mean 65.5 years) with pathologically proven COP were retrospectively analyzed by a consensus of two experienced chest radiologists for the existence and distribution of airspace consolidation, ground-glass opacities, nodular thickening along bronchovascular bundles, small (<1 cm) and large (>1 cm) nodules. The distribution of radiologic findings was classified as unilateral or bilateral, located in the upper, lower or middle lobe, and central or peripheral. Also recorded was the presence or absence of mediastinal lymphadenopathy and pleural effusion. Correlation with clinical symptoms was analyzed.

Results: All eight patients had bilateral airspace consolidations: in two cases consolidations were limited to central fields, in four they were peripheral, and in the remaining two cases they were both central and peripheral. Small nodules were noted in six cases and large nodules in three. Ground-glass opacities were found in four cases. All patients had enlarged lymph nodes (1–1.5 cm) in the mediastinum. Radiologic abnormalities resolved or improved after steroid treatment in all patients.

Conclusions: HRCT findings of bilateral multiple heterogenic lung infiltrates and nodules associated with mild mediastinal lymphadenopathy in a patient with non-specific clinical symptoms are suggestive of COP; in such cases, lung biopsy is indicated. Radiologic resolution of abnormalities correlates well with clinical improvement under adequate steroid treatment.

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[1] COP = cryptogenic organizing pneumonia

[2] HRCT = high resolution computerized tomography

Background: Abdominal tuberculosis usually presents with general symptoms and obscure abdominal complaints for which computerized tomography is often the first imaging study.

Objective: To evaluate the CT findings of abdominal tuberculosis.

Methods: The CT scans of 19 patients (10 men and 9 women aged 20-85 years) with proven abdominal tuberculosis were retrospectively reviewed to define the location and extent of the disease. The patients were referred for the study mainly with general systemic symptoms. Additional abdominal com­plaints were present in four, including acute abdomen in one. Two had symptoms deriving from the urinary tract. Nine patients had recently arrived from high prevalence countries five of them and two others were positive for human immunodeficiency virus. Three patients had a family history of tuberculosis one had previously been treated for tubercu­losis and four others had an underlying chronic disease. The diagnosis of tuberculosis was established by standard micro­biological and histological techniques.

Results: We divided the disease manifestations into intraperitoneal (n-13) and genitourinary involvement (n- 6). Peritoneal tuberculosis was fairly common, characterized by ascites, omental and mesenteric infiltration, and smooth thickening of the parietal peritoneum. One oncology patient had a false positive Tc-99m CEA isotope scanning, suggesting tumor recurrence. Genitourinary disease manifested mainly as hydronephrosis and calcifications. Three patients had pulmon­ary tuberculosis as well.

Conclusion: The CT findings of abdominal tuberculosis may mimic various diseases, mainly diffuse peritoneal malig­nancy. We emphasize the need to consider tuberculosis in the differential diagnosis in patients with obscure abdominal symptoms, especially with multi-organ involvement. A high degree of clinical suspicion and familiarity with the abdominal CT manifestations allow early diagnosis of this treatable disease.

Background: Protruding aortic atheromas are a potential source of stroke and systemic emboli. The single modality currently available for their detection has been transesophageal echocardiography. However, TEE does not allow full visualization of the upper part of the ascending aorta and proximal aortic arch.

Objectives: To investigate whether double helical computerized tomography- both with and without contrast injection - may represent a useful technique for noninvasive detection of PAA in stroke patients.

Methods: Forty consecutive patients ≥50 years of age who sustained a recent ischemic stroke and/or systemic emboli (within 15 days after the onset of the event) were enrolled in the study and underwent TEE and DHCT without contrast injection using thin slice acquisition (3.2 mm thickness and 1.5 mm reconstruction increment). In addition, the last eight consecutive patients, after obtaining an unenhanced scan, underwent a contrast-enhanced DHCT following peripheral intravenous injection of a small amount of contrast material (15 ml of diatrizoate).

Results: PAAs were demonstrated by TEE in 18 patients (45%); in 16 of them (89%) the atheromas were recognized by DHCT. Of the 22 patients without PAA on TEE, DHCT confirmed their absence in 18 (82%). DHCT yielded a sensitivity of 89%, a specificity of 82%, and an overall accuracy of 85%. The total number of protruding plaques detected by TEE was 43, of which 41 (95%) were correctly identified by DHCT. The mean thickness of the plaques was 5.6±2.4 mm on TEE, and 5.4±2.3 on DHCT (P=NS), with a good correlation between the modalities (γ=0.84). Contrast-enhanced DHCT scans demonstrated absolute equivalence to TEE in aortic areas defined as "clearly visualized by TEE." DHCT detected PAA between the distal ascending aorta and the proximal arch in seven patients; these atheromas were not included in the comparative analysis. In these "occult" areas, DHCT may be superior to TEE.

Conclusions: DHCT without contrast injection using thin slice acquisition may become a useful modality for rapid noninvasive detection of PAA. Contrast-enhanced DHCT scans significantly improve imaging quality and may be superior to TEE in the upper ascending aorta and the proximal arch (areas not well visualized by TEE).

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TEE= transesophgeal echocardiography

PAA= protruding aortic atheroma

DHCT= dual helical computerized tomography
 

Objective: To evaluate the contribution of computerized tomography to the diagnosis of Takayasu's arteritis.

Methods: A retrospective analysis of the diagnostic process was recently conducted in three consecutive patients diagnosed over the last 3 years.

Results: Three females of Arab origin with Takayasu's arteritis were recently identified by CT. In two of the three patients the imaging procedure was performed for different working hypotheses, and the radiological findings (wall thickening, perivascular edema, and segmental intraluminal obliteration of the aorta and its major branches) were unexpected. In these two patients, repeated physical examination following the imaging procedure disclosed initially missed findings that could have led to an earlier consideration of Takayasu's arteritis (bruits above the epigastrium, subclavian and carotid arteries, and absent brachial pulses). Retrospective analysis of the patients' symptoms following CT revealed the true nature of the patients' misinterpreted complaints (e.g., typical abdominal angina replaced a faulty obtained history compatible with renal colic or dyspepsia). In the third patient CT was performed for the evaluation of an epigastric bruit associated with constitutional complaints. The diagnosis of aortitis, based upon the presence of diffuse aortic wall thickening and edema of the surrounding fat, without intraluminal narrowing, could have been missed by angiography, the traditional "gold standard" diagnostic procedure. All three patients complained of ill-defined epigastric abdominal pain and had epigastric tenderness during examination.

Conclusions: CT has the potential for detecting Takayasu's disease and may be superior to angiography, particularly at the early non-obliterative stage. Since the diagnosis of Takayasu's disease is rarely considered, the expanding use of CT and MRI technologies may reveal missed cases that are evaluated for other plausible diagnoses. The true incidence of Takayasu's arteritis in Israel may be much higher than reported, particularly in the Arab population. Our findings suggest that epigastric tenderness, originating from active inflammatory reaction in the abdominal aortic wall, should be considered as a diagnostic criterion of Takayasu's aortitis.